UNIVERSE OLDER THAN EXPECTED
Dr. Jai Maharaj
European Space Agency News Release
Wednesday, July 10, 2002
An analysis of 13.5 thousand million-year-old X-rays,
captured by ESA's XMM-Newton satellite, has shown that
either the Universe may be older than astronomers had
thought or that mysterious, undiscovered 'iron factories'
litter the early Universe.
View image here:
http://www.spaceflightnow.com/news/n0207/10age/artists.jpg
[Caption] Artist's impression of the new 'unified model'
for the different kinds of quasar activity. Photo: PA/MPE
ESA's Norbert Schartel and colleagues from the Max-
Planck-Institut für extraterrestrische Physik,Germany,
found more iron than anyone thought possible in the
extremely distant celestial object, APM 8279+5255. The
object is a quasar, that is, a young galaxy containing an
incredibly bright central region, caused by gas falling
into a giant black hole.
APM 8279+5255 is 13.5 thousand million light years away.
Scientists know this because they have estimated a
property of its light known as the red shift, which is
caused by the expansion of the Universe stretching the
wavelengths of light emitted by the celestial object.
XMM-Newton's data showed that iron was three times more
abundant in the quasar than in our Solar System.
Since iron is released by exploding stars, according to
precise physical phenomena, and scientists think it
builds up across the Universe gradually with time. The
Solar System formed just 5 thousand million years ago, so
it should contain more iron than the quasar, which formed
over 13.5 thousand million years ago. The fact that the
quasar contains three times more iron than the Sun is
therefore a major puzzle.
One possible explanation is that something is wrong with
the way astronomers measure the age of objects in the
Universe. The almost-holy red shift-distance-age
conversion would therefore be wrong. Fred Jansen, ESA's
project scientist for XMM-Newton, explains that this
would mean rewriting the textbooks. "If you study the
evolution of the Universe, one of the basic rules is that
we can tie redshift to age. One distinct possibility to
explain these observations is that, at the redshift we
are looking at, the Universe is older than we think."
View image here:
http://www.spaceflightnow.com/news/n0207/10age/xmm.jpg
[Caption] Spectrum of the quasar APM 08279+5255, showing
iron-cloud traces. The left picture shows a photo of the
quasar, taken by XMM-Newton. The dip in the spectrum of
the quasar APM 08279+5255 is caused by the element iron.
In a same way that our bones appear dark in X-ray
photographs because they are opaque to X-rays, the
outflowing iron clouds of APM 08279+5255 are opaque for
X-rays that are created at the quasar's centre. At the
'absorption energy' characteristic for iron (marked by
the red arrow), some part of the X-ray light is missing.
Photo: ESA, Graphics: MPE
If the older-Universe interpretation is wrong, there is
only one other, stranger possibility, according to
Jansen. Somewhere in the early Universe there must be
undiscovered 'iron factories', producing the metal by
unknown physical means. Understandably, Jansen is
cautious about this, saying, "This is the less likely
solution in my opinion."
If such mysterious objects exist, perhaps XEUS (a next-
generation X-ray satellite currently under study by ESA
for launch sometime in the next decade) will discover
them, because it will have the ability to see the very
first galaxies.
In the shorter term, ESA is launching INTEGRAL, a gamma-
ray-detecting satellite, in October 2002. It will observe
exploding stars to study the formation of chemical
elements and may explain the anomalous iron observations.
The paper containing these results is published on 10
July 2002, in Astrophysical Journal Letters, Vol. 573,
L77. The authors were G. Hasinger and S. Komossa at the
Max-Planck-Institut für Extraterrestrische Physik and N.
Schartel at the European Space Agency.
Read the complete news and features at:
http://www.spaceflightnow.com/news/n0207/10age/
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aryanviking
Dr. Jai Maharaj wrote:
> Is the Universe older than expected?
---> blah blah blah -- same old story -- these astronuts keep coming up
with some theory or the other every few days -- maybe they gotto show
soemthing for all that funding -- seems like they function like some MNC
mafia who keep coming up with 'latest updated' versions/models once in
a while so that you are compelled to throw that older one and dish out
money for the 'latest' ---
X
Dr. Jai Maharaj wrote:
> Is the Universe older than expected?
>
> European Space Agency News Release
> Wednesday, July 10, 2002
>
> An analysis of 13.5 thousand million-year-old X-rays,
> captured by ESA's XMM-Newton satellite, has shown that
> either the Universe may be older than astronomers had
> thought or that mysterious, undiscovered 'iron factories'
> litter the early Universe.
Possibly what we can see as our universe and attempt to gauge the age of
is just a swinging arm of it, hurling outward in an arc, just a part of
the possible bang like a swirling eddy in a viewable explosion, so this
is might be what we've been aging. The X-rays might be a product of the
whole universe that we can't see and evidence of the bigger picture.
Next are where the "thought police" come in to attack my statement.
-X
Sam Wormley
Ref: http://xxx.lanl.gov/abs/astro-ph/0109232
The Age of the Universe and the Cosmological Constant Determined from Cosmic
Microwave Background Anisotropy Measurements
Authors: L. Knox (1), N. Christensen (2), C. Skordis (1) ((1) UC Davis (2)
Carleton College)
Comments: 5 pages, including 2 figures and one table final published version
Journal-ref: Astrophys. J. 563, L95 (2001)
If Omega_tot = 1 and structure formed from adiabatic initial conditions
then the age of the Universe, as constrained by measurements of the cosmic
microwave background (CMB), is t_0=14.0 +/- 0.5 Gyr. The uncertainty is
surprisingly small given that CMB data alone constrain neither h nor
Omega_Lambda significantly. It is due to the tight (and accidental)
correlation, in these models, of the age with the angle subtended by the
sound horizon on the last--scattering surface and thus with the
well-determined acoustic peak locations. If we assume either the HST Key
Project result h = 0.72 \pm .08 or simply that h > 0.55, we find
Omega_Lambda > 0.4 at 95% confidence--another argument for dark energy,
independent of supernovae observations. Our analysis is greatly simplified
by the Monte Carlo Markov chain approach to Bayesian inference combined
with a fast method for calculating angular power spectra.
Ref: http://xxx.lanl.gov/abs/astro-ph/0109232
Science News, Vol. 160, No. 17, Oct. 27, 2001, p. 261
http://www.sciencenews.org/20011027/fob3.asp
Age of the universe: A new determination
by Ron Cowen
"Analyzing the faint glow left over from the Big Bang, scientists report
measuring the age of the cosmos with unprecedented accuracy. They claim
the age they calculate, 14 billion years, is accurate to within half a
billion years". See: http://www.sciencenews.org/20011027/fob3.asp which
includes references.
Also: http://background.uchicago.edu/~whu/beginners/introduction.html.
http://www.astro.ucla.edu/~wright/age.html
http://www.hep.upenn.edu/~max/cmb/experiments.html
-Sam Wormley
http://edu-observatory.org/eo/cosmology.html
Bennett Standeven
> Is the Universe older than expected?
>
> European Space Agency News Release
> Wednesday, July 10, 2002
>
> An analysis of 13.5 thousand million-year-old X-rays,
> captured by ESA's XMM-Newton satellite, has shown that
> either the Universe may be older than astronomers had
> thought or that mysterious, undiscovered 'iron factories'
> litter the early Universe.
>
>
> Since iron is released by exploding stars, according to
> precise physical phenomena, and scientists think it
> builds up across the Universe gradually with time. The
> Solar System formed just 5 thousand million years ago, so
> it should contain more iron than the quasar, which formed
> over 13.5 thousand million years ago. The fact that the
> quasar contains three times more iron than the Sun is
> therefore a major puzzle.
>
> One possible explanation is that something is wrong with
> the way astronomers measure the age of objects in the
> Universe. The almost-holy red shift-distance-age
> conversion would therefore be wrong. Fred Jansen, ESA's
> project scientist for XMM-Newton, explains that this
> would mean rewriting the textbooks. "If you study the
> evolution of the Universe, one of the basic rules is that
> we can tie redshift to age. One distinct possibility to
> explain these observations is that, at the redshift we
> are looking at, the Universe is older than we think."
>
How would that help? To explain the results, the Universe would have
to have been older 13.5 billion years ago than it is now. That doesn't
seem very likely...
Martin Gradwell
Bennett Standeven <be...@pop.networkusa.net> wrote in message
news:24c3076b.02072...@posting.google.com...
> use...@mantra.com (Dr. Jai Maharaj) wrote in message
news:<Jyotish-17...@news.mantra.com>...
> > Is the Universe older than expected?
> > One possible explanation is that something is wrong with
> > the way astronomers measure the age of objects in the
> > Universe. The almost-holy red shift-distance-age
> > conversion would therefore be wrong. Fred Jansen, ESA's
> > project scientist for XMM-Newton, explains that this
> > would mean rewriting the textbooks. "If you study the
> > evolution of the Universe, one of the basic rules is that
> > we can tie redshift to age. One distinct possibility to
> > explain these observations is that, at the redshift we
> > are looking at, the Universe is older than we think."
> >
>
> How would that help? To explain the results, the Universe would have
> to have been older 13.5 billion years ago than it is now. That doesn't
> seem very likely...
How about if it was exactly the same age, 13.5 billion years
ago, as it is today?
If you read carefully, the claim is that the quasar, 13.5 billion
years ago, might have been older than *our solar system* is
today (because it contains a higher proportion of iron than
our sun does). Older than our solar system, *not* older than
our universe.
Suppose, for example, that the quasar was formed 28.5 billion
years ago. It would then have been 15 billion years old at the
time when it emitted the light that we see today. That's three
times the current age of our solar system. We might then expect
it to have three times the iron content of our sun, if iron content
was linearly related to age.
Of course the relationship is not linear - that's just a simplifying
assumption. There are few straightforward linear relationships
in the real universe. It is the notion that our simplifying assumptions
have some sort of universal validity, and in particular that distance
is linearly related to Hubble redshift, which has led to the nonsense
that is only now starting to be dispelled.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
George Dishman
news:ai0bnf$jgv$1...@newsg1.svr.pol.co.uk...
>
> Of course the relationship is not linear - that's just a simplifying
> assumption. There are few straightforward linear relationships
> in the real universe. It is the notion that our simplifying assumptions
> have some sort of universal validity, and in particular that distance
> is linearly related to Hubble redshift, which has led to the nonsense
> that is only now starting to be dispelled.
The linear relationship refers to a specific definition of distance
http://www.astro.ucla.edu/~wright/cosmo_02.htm#md
Lookback time probably gives a better idea of the curve in more usual
units. This is from a MathCad tutorial and may not represent the latest
observational values but the graph on page 2 illustrates the non-linear
aspect quite well.
http://www.briar.demon.co.uk/Aladar/HubbleConstant/LookBackTime.pdf
--
George Dishman
The arrow of time points in many directions.
Martin Gradwell
George Dishman <geo...@briar.demon.co.uk> wrote in message
news:1027855226.6083.0...@news.demon.co.uk...
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:ai0bnf$jgv$1...@newsg1.svr.pol.co.uk...
> >
> > Of course the relationship is not linear - that's just a simplifying
> > assumption. There are few straightforward linear relationships
> > in the real universe. It is the notion that our simplifying assumptions
> > have some sort of universal validity, and in particular that distance
> > is linearly related to Hubble redshift, which has led to the nonsense
> > that is only now starting to be dispelled.
>
> The linear relationship refers to a specific definition of distance
>
> http://www.astro.ucla.edu/~wright/cosmo_02.htm#md
Thanks for the link. This page shows that the supposed linear
relationship doesn't even correspond to anything observable:
"the homogeneity of the Universe must be defined on a surface
of constant proper time since the Big Bang" - but we are not in
a position to station observers on such a surface, or even to
know with certainty that such a surface can exist. Instead we
extrapolate from what we can actually see, and in doing so we
assume the validity of what we ought to be trying to prove.
The result of all this extrapolation and assumption is supposed
to show that the expansion is indeed linear (given an appropriate
definition of distance), and that the universe is homogeneous
and isotropic and began with a big bang, but I do not see how
it shows any of these things.
>
> Lookback time probably gives a better idea of the curve in more usual
> units.
I agree that lookback time is more appropriate. This is because
we can be sure that light from apparently distant galaxies originated
a long time ago, but we cannot be so sure about spatial separations.
If light is not constrained to follow straight line paths, some of the
most apparently distant images might be of the local region of space.
> This is from a MathCad tutorial and may not represent the latest
> observational values but the graph on page 2 illustrates the non-linear
> aspect quite well.
>
> http://www.briar.demon.co.uk/Aladar/HubbleConstant/LookBackTime.pdf
This page at least states the assumptions it is making.
Friedmann model, pressure and cosmological constant
both zero, deceleration parameter = 0, 1/2 or 1 for the
curves depicted, Hubble "constant" a variable parameter
equal to 72 for the curves depicted. It tells us what the
relationship between redshift and lookback time will be
if these assumptions are true. It does not give us any
reason to suppose that any of these assumptions are true.
>
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
George Dishman
It doesn't, it is the other way round. If the relationship wasn't
linear, we would expect some regions to expand more rapidly than
others and hence have lower density. That is of course true at
the scale of galaxies and groups but on very large scales there
seems to be no such structure. We observe that the distribution
is homogenous and isotropic so conclude that the relationship,
when expressed in those particular coordinates, should be linear.
The choice of that distance definition avoids making additional
assumptions. The lookback time then comes from applying the
various models to figure out what the universe was like in the
past based on what we see now.
> > Lookback time probably gives a better idea of the curve in more usual
> > units.
>
> I agree that lookback time is more appropriate. This is because
> we can be sure that light from apparently distant galaxies originated
> a long time ago, but we cannot be so sure about spatial separations.
Right, we have no way to measure distance directly over these
scales.
> If light is not constrained to follow straight line paths, some of the
> most apparently distant images might be of the local region of space.
That depends on what you mean by 'local'. Gravitational lensing
is well understood and many examples have been observed.
> > This is from a MathCad tutorial and may not represent the latest
> > observational values but the graph on page 2 illustrates the non-linear
> > aspect quite well.
> >
> > http://www.briar.demon.co.uk/Aladar/HubbleConstant/LookBackTime.pdf
>
> This page at least states the assumptions it is making.
> Friedmann model, pressure and cosmological constant
> both zero, deceleration parameter = 0, 1/2 or 1 for the
> curves depicted, Hubble "constant" a variable parameter
> equal to 72 for the curves depicted.
I edited that value some time ago based on the Hubble Key Project
that found 72 +/- 8 km/s per MPc. I haven't attempted to correct
the other parameters though they are better constrained now.
I just wanted to illustrate that the relationship in more
familiar terms is far from linear.
>It tells us what the
> relationship between redshift and lookback time will be
> if these assumptions are true. It does not give us any
> reason to suppose that any of these assumptions are true.
No, of course not. That comes from the observations that we
plug into the models to try to estimate the other parameters,
and even more fundamentally to decide which is the best model
to use in the first place.
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:ai2mle$313$1...@newsg2.svr.pol.co.uk...
> >
> > George Dishman <geo...@briar.demon.co.uk> wrote in message
> > news:1027855226.6083.0...@news.demon.co.uk...
> > > The linear relationship refers to a specific definition of distance
> > >
> > > http://www.astro.ucla.edu/~wright/cosmo_02.htm#md
> >
> > Thanks for the link. This page shows that the supposed linear
> > relationship doesn't even correspond to anything observable:
> > "the homogeneity of the Universe must be defined on a surface
> > of constant proper time since the Big Bang" - but we are not in
> > a position to station observers on such a surface, or even to
> > know with certainty that such a surface can exist. Instead we
> > extrapolate from what we can actually see, and in doing so we
> > assume the validity of what we ought to be trying to prove.
> >
> > The result of all this extrapolation and assumption is supposed
> > to show that the expansion is indeed linear (given an appropriate
> > definition of distance), and that the universe is homogeneous
> > and isotropic and began with a big bang, but I do not see how
> > it shows any of these things.
>
> It doesn't, it is the other way round. If the relationship wasn't
> linear, we would expect some regions to expand more rapidly than
> others and hence have lower density.
And you do not think this is what is observed?
"Looking further into space, at a distance of perhaps 350
million light years, Margaret Geller and John Huchra of the
Harvard-Smithsonian center for Astrophysics have discovered
a giant sheet of galaxies - the _Great Wall_ - which stretches
more than 500 million light years across the sky".
- from "The inflationary universe" by Alan H. Guth, p214.
There are even larger looking sheets at greater apparent
distances, and they seem to separate huge bubble-like voids
each hundreds of millions of light years across and devoid
of any matter. Then there is the "Lyman alpha forest" in the
spectra of distant hydrogen emissions, which shows that
intergalactic gas is collected into vast sheets separated by
vast spaces.
How big does a structure have to be before you will
consider it big? 500 million light years across is even
bigger than Texas. That is *big*!
> That is of course true at
> the scale of galaxies and groups but on very large scales there
> seems to be no such structure.
For "no such", read "such a". Except in regions more
than a billion light years across. That is, I contend, at
scales larger than the scale of the physical universe.
> We observe that the distribution
> is homogenous and isotropic so conclude that the relationship,
> when expressed in those particular coordinates, should be linear.
This is like a person in a hall of mirrors, surrounded entirely by
distorting mirrors, concluding that the universe is a homogeneous
and isotropic collection of people all resembling distorted images
of himself. Note I don't say that there are any actual mirrors, but
if light can be made to follow closed orbits by gravity, that has an
effect similar to the effect of a hall of mirrors. We see distant
distorted images of local objects. We see homogeneity and
isotropy, but this does not mean there is any real homogeneity
or isotropy.
Note that if the universe really was homogeneous, it would
not appear so. This is because "the homogeneity of the
Universe must be defined on a surface of constant proper
time since the Big Bang", and we do not see events on such
a surface. We see events on our "past light cone".
So, we ought to see younger galaxies at greater distances.
Instead we see, as in the title of this thread,
"UNIVERSE OLDER THAN EXPECTED".
Quasars are surrounded by an iron-rich environment.
This is because they are surrounded by galaxies that are
very old indeed, and were very old at the time when
they emitted the light that we see today. Their age is
certainly not constrained by any figure we might obtain
by calculating the rate of universal "expansion" and
extrapolating backwards. The "evidence" for young
quasars is like Percival Lowell's evidence for canals
on Mars. It is wishful thinking on the part of observers
who really want the big bang theory to be true.
> The choice of that distance definition avoids making additional
> assumptions.
There are enough assumptions being made in arriving at
that distance defintion. More would certainly be superfluous.
> The lookback time then comes from applying the
> various models to figure out what the universe was like in the
> past based on what we see now.
What do you think we see now?
>
> > > Lookback time probably gives a better idea of the curve in more usual
> > > units.
> >
> > I agree that lookback time is more appropriate. This is because
> > we can be sure that light from apparently distant galaxies originated
> > a long time ago, but we cannot be so sure about spatial separations.
>
> Right, we have no way to measure distance directly over these
> scales.
>
> > If light is not constrained to follow straight line paths, some of the
> > most apparently distant images might be of the local region of space.
>
> That depends on what you mean by 'local'. Gravitational lensing
> is well understood and many examples have been observed.
And yet, people are remarkably unwilling to suppose that
there can be cosmic-scale lensing, affecting everything we
see over large patches of the sky. This is because they are
convinced of the supposed homogeneity, and cannot see
that cosmic lensing can create the illusion of homogeneity
where in reality there is none.
"Local" is not easy to define in a universe where the
galaxies are in motion with respect to one another, but
I think it is reasonable to use the great attractor as a
reference point. In falling towards the attractor, our
galaxy follows a trail that was blazed long ago by other
similar galaxies. If such a galaxy is now closer to the
attractor than we are, we can say that it once occupied
the space that our galaxy now occupies. When we see
distant images of that galaxy in its youth, when it was as
old as our galaxy is now, we are seeing an image of the
local region of space.
>
> > > This is from a MathCad tutorial and may not represent the latest
> > > observational values but the graph on page 2 illustrates the
non-linear
> > > aspect quite well.
> > >
> > > http://www.briar.demon.co.uk/Aladar/HubbleConstant/LookBackTime.pdf
> >
> > This page at least states the assumptions it is making.
> > Friedmann model, pressure and cosmological constant
> > both zero, deceleration parameter = 0, 1/2 or 1 for the
> > curves depicted, Hubble "constant" a variable parameter
> > equal to 72 for the curves depicted.
>
> I edited that value some time ago based on the Hubble Key Project
> that found 72 +/- 8 km/s per MPc. I haven't attempted to correct
> the other parameters though they are better constrained now.
> I just wanted to illustrate that the relationship in more
> familiar terms is far from linear.
>
> >It tells us what the
> > relationship between redshift and lookback time will be
> > if these assumptions are true. It does not give us any
> > reason to suppose that any of these assumptions are true.
>
> No, of course not. That comes from the observations that we
> plug into the models to try to estimate the other parameters,
> and even more fundamentally to decide which is the best model
> to use in the first place.
I'm glad that you can see that.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
George Dishman
IIRC, homogeneity is on a scale greater than about 1 billion
light years. There is a reference in Peebles "Principles of
Physical Cosmology" to some papers but I don't have it handy.
> > That is of course true at
> > the scale of galaxies and groups but on very large scales there
> > seems to be no such structure.
>
> For "no such", read "such a". Except in regions more
> than a billion light years across. That is, I contend, at
> scales larger than the scale of the physical universe.
We seem to be in rough agreement on the scale, but the information
I have seen suggests the size is much greater, probably infinite
but the most distant objects we have seen would 'now' be at least
80 billion light years away. I have seen nothing to suggest the
universe is finite.
> > We observe that the distribution
> > is homogenous and isotropic so conclude that the relationship,
> > when expressed in those particular coordinates, should be linear.
>
> This is like a person in a hall of mirrors, surrounded entirely by
> distorting mirrors, concluding that the universe is a homogeneous
> and isotropic collection of people all resembling distorted images
> of himself. Note I don't say that there are any actual mirrors, but
> if light can be made to follow closed orbits by gravity,
It cannot, expect possibly as an unstable orbit at a critical
distance around a black hole.
> effect similar to the effect of a hall of mirrors. We see distant
> distorted images of local objects. We see homogeneity and
> isotropy, but this does not mean there is any real homogeneity
> or isotropy.
All the examples we see of gravitatonal lensing have deflections
which are very small. If large deflections were commonplace we
should expect a kaliedoscope effect with the appearance of
galaxies being more disrupted the further away they are. I have
not seen any evidence for anything like that. On the scale you
suggest, anything beyond 1 billion light years should be
severly distorted. That is certainly not the case.
> Note that if the universe really was homogeneous, it would
> not appear so. This is because "the homogeneity of the
> Universe must be defined on a surface of constant proper
> time since the Big Bang", and we do not see events on such
> a surface. We see events on our "past light cone".
> So, we ought to see younger galaxies at greater distances.
I believe we do see a difference in the ratio of globular
to elliptical galaxies though I don't know the details.
> Instead we see, as in the title of this thread,
> "UNIVERSE OLDER THAN EXPECTED".
Good, something new to learn.
<snip>
> > The lookback time then comes from applying the
> > various models to figure out what the universe was like in the
> > past based on what we see now.
>
> What do you think we see now?
A picture that is mostly consistent with the big bang, but
with too many unknowns to think we have anything like the
whole story.
> > > If light is not constrained to follow straight line paths, some of the
> > > most apparently distant images might be of the local region of space.
> >
> > That depends on what you mean by 'local'. Gravitational lensing
> > is well understood and many examples have been observed.
>
> And yet, people are remarkably unwilling to suppose that
> there can be cosmic-scale lensing, affecting everything we
> see over large patches of the sky. This is because they are
> convinced of the supposed homogeneity, and cannot see
> that cosmic lensing can create the illusion of homogeneity
> where in reality there is none.
I can see that 'cosmic lensing' might uniformly magnify
distant objects, and I believe that is part of some
current theories but I cannot see how it could create
the effect you describe.
> "Local" is not easy to define in a universe where the
> galaxies are in motion with respect to one another, but
> I think it is reasonable to use the great attractor as a
> reference point. In falling towards the attractor, our
> galaxy follows a trail that was blazed long ago by other
> similar galaxies. If such a galaxy is now closer to the
> attractor than we are, we can say that it once occupied
> the space that our galaxy now occupies. When we see
> distant images of that galaxy in its youth, when it was as
> old as our galaxy is now, we are seeing an image of the
> local region of space.
No, we are seeing an image of that galaxy when it was between
us and the Attractor. The Attractor was discovered by mapping
the flow of galaxies being drawn to it. Any significant lensing
as you describe would so disrupt the appearance of the flow, I
doubt we would even se a pattern.
> > >It tells us what the
> > > relationship between redshift and lookback time will be
> > > if these assumptions are true. It does not give us any
> > > reason to suppose that any of these assumptions are true.
> >
> > No, of course not. That comes from the observations that we
> > plug into the models to try to estimate the other parameters,
> > and even more fundamentally to decide which is the best model
> > to use in the first place.
>
> I'm glad that you can see that.
I think you feel science is more certain of the models than it
really is. There is still a lot to learn.
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:ai4c39$b12$1...@newsg3.svr.pol.co.uk...
> >
> > George Dishman <geo...@briar.demon.co.uk> wrote in message
> > news:1027967692.26323....@news.demon.co.uk...
> > > If the relationship wasn't linear, we would expect some
> > > regions to expand more rapidly than others and hence
> > > have lower density.
> >
> > And you do not think this is what is observed?
> > How big does a structure have to be before you will
> > consider it big? 500 million light years across is even
> > bigger than Texas. That is *big*!
>
> IIRC, homogeneity is on a scale greater than about 1 billion
> light years. There is a reference in Peebles "Principles of
> Physical Cosmology" to some papers but I don't have it handy.
> We seem to be in rough agreement on the scale, but the information
> I have seen suggests the size is much greater, probably infinite
> but the most distant objects we have seen would 'now' be at least
> 80 billion light years away. I have seen nothing to suggest the
> universe is finite.
The information you have seen probably implies, without
justification, that the radius of the universe is at least equal
to the greatest distance that we can see. This would not be
the case in a closed universe in which light could follow
a closed orbit multiple times before being detected.
If we can equate path length with apparent distance
then light which has followed a closed orbit of length
2 billion light years, and has done so three times, will
seem to come from a distance of six billion light years.
You will see very little in the literature which suggests
that the universe is as small as I think it is, but you will
find plenty that suggests it is finite. This notion may be
drifting out of fashion, but fashion is not an indicator
of correctness.
There are scientists who understand that the physical
universe can be smaller than what we observe, and
in that case we will see multiple distorted images of the
physical universe at varying distances. See e.g.
"Topological lens effects in universes with non-Euclidean
compact spatial sections", by Lehoucq, R.; Luminet, J.-P.;
and Uzan, J.-Ph:
"Universe models with compact spatial sections smaller
than the observable universe produce a topological lens
effect. ... Numerical calculations in the Weeks manifold
allow us to check the absence of crystallographic signature
of topology, due to the fact that the number of copies
of the fundamental domain in the observable covering
space is low and that the points are not moved the same
distance by the holonomies of space."
See http://xxx.lpthe.jussieu.fr/abs/astro-ph/9811107
>
> > > We observe that the distribution
> > > is homogenous and isotropic so conclude that the relationship,
> > > when expressed in those particular coordinates, should be linear.
> >
> > This is like a person in a hall of mirrors, surrounded entirely by
> > distorting mirrors, concluding that the universe is a homogeneous
> > and isotropic collection of people all resembling distorted images
> > of himself. Note I don't say that there are any actual mirrors, but
> > if light can be made to follow closed orbits by gravity,
>
> It cannot, expect possibly as an unstable orbit at a critical
> distance around a black hole.
.. or around a universe which is in many ways like the interior
of a black hole, i.e. which is sufficiently massive and compact
to be closed.
"Critical distance"? That only makes sense for circular orbits.
Why does nobody consider the possibility that light needn't
follow circular orbits? Do comets follow circular orbits?
>
> > effect similar to the effect of a hall of mirrors. We see distant
> > distorted images of local objects. We see homogeneity and
> > isotropy, but this does not mean there is any real homogeneity
> > or isotropy.
>
> All the examples we see of gravitational lensing have deflections
> which are very small.
All the examples that have been *identified as such* have
deflections that appear to be small.
Suppose that two quasars on opposite sides of the sky
were in fact different images of the same object. How would
we determine that this was the case? It's no use comparing
spectra or luminosity .. quasars fluctuate from day to day,
even sometimes from minute to minute. It's only when the
path length difference between the two images is very small,
maybe just a couple of years different, that we can see the
two images fluctuate in step, give or take a year or two.
In practice this only happens when the images are very close
together. This might mean that the deflection of both images
is small, or it might mean that one is deflected by 23 degrees,
say, and the other is deflected by 23.001 degrees.
> If large deflections were commonplace we
> should expect a kaliedoscope effect with the appearance of
> galaxies being more disrupted the further away they are. I have
> not seen any evidence for anything like that. On the scale you
> suggest, anything beyond 1 billion light years should be
> severly distorted. That is certainly not the case.
The whole field of view can be severely distorted by
cosmic-scale lensing, and the individual specks of galaxies
will still look like galaxies, albeit stretched out. This stretching
is not all that noticeable - it just makes some galaxies look more
elliptical than they ought to, and others less elliptical than
they ought to. It is the very *small* scale distortion, caused
by individual galaxies, which results in gross and easily seen
distortions of the images of individual lensed galaxies.
But, radio galaxies usually have jets that emerge from the
poles, at right angles to the plane of the galaxy. Shear the
images and the radio image will align more or less with the
optical image instead of being at right angles to it. This is
what is observed at great apparent distances. This, and
a proportion of unusually elongated and misshapen galaxies,
consistent with the images of those galaxies being sheared.
It certainly is the case that there are spectacular examples
of gravitational lensing resulting in multiple images of single
galaxies, and these examples are nore noticeable at greater
apparent distances.
>
> > Note that if the universe really was homogeneous, it would
> > not appear so. This is because "the homogeneity of the
> > Universe must be defined on a surface of constant proper
> > time since the Big Bang", and we do not see events on such
> > a surface. We see events on our "past light cone".
> > So, we ought to see younger galaxies at greater distances.
>
> I believe we do see a difference in the ratio of globular
> to elliptical galaxies though I don't know the details.
Shearing and stretching distortion will tend to make globular
galaxies look elliptical. However, this effect is insignificant
compared to the fact that globular galaxies are generally smaller
than elliptical ones, and can't be expected to be visible over
distances of billions of light years.
>
> > Instead we see, as in the title of this thread,
> > "UNIVERSE OLDER THAN EXPECTED".
>
> Good, something new to learn.
I'm impressed by your attitude.
>
> <snip>
> > > The lookback time then comes from applying the
> > > various models to figure out what the universe was like in the
> > > past based on what we see now.
> >
> > What do you think we see now?
>
> A picture that is mostly consistent with the big bang, but
> with too many unknowns to think we have anything like the
> whole story.
Compare that with what we ought to see now, if the
big bang theory really was an accurate description of
the universe.
..
> I can see that 'cosmic lensing' might uniformly magnify
> distant objects,
"uniformly". You are hooked on the idea of homogeneity.
> and I believe that is part of some
> current theories but I cannot see how it could create
> the effect you describe.
By inhomogeneity. By a preponderance of mass in
one spatial direction causing a consistent lage scale
shift of visible images across the whole of the sky.
By this shift causing images to appear in directions and
at apparent distances where there is no corresponding
actual object
>
> > "Local" is not easy to define in a universe where the
> > galaxies are in motion with respect to one another, but
> > I think it is reasonable to use the great attractor as a
> > reference point. In falling towards the attractor, our
> > galaxy follows a trail that was blazed long ago by other
> > similar galaxies. If such a galaxy is now closer to the
> > attractor than we are, we can say that it once occupied
> > the space that our galaxy now occupies. When we see
> > distant images of that galaxy in its youth, when it was as
> > old as our galaxy is now, we are seeing an image of the
> > local region of space.
>
> No, we are seeing an image of that galaxy when it was between
> us and the Attractor.
That is one of the images that we see .. the nearest one.
But the galaxy can emit light in other directions too, not
just directly towards us. If this light is bent around, following
a closed orbit, it can eventually reach us from a direction
*opposite* to the direction of the galaxy from which it was
emitted. We then perceive that galaxy as a distant galaxy in
the direction of Perseus, say.
> The Attractor was discovered by mapping
> the flow of galaxies being drawn to it. Any significant lensing
> as you describe would so disrupt the appearance of the flow, I
> doubt we would even se a pattern.
The effect of the lensing is to make the "Hubble Flow" seem
to prevail over the whole of the sky, even though galaxies are
being drawn together over a region many hundreds of millions
of light years across. Because of the lensing, even galaxies
which are on the other side of the attractor, being rapidly
drawn towards it and by implication towards us, still appear
redshifted.
As you say, "Any significant lensing as you describe
would so disrupt the appearance of the flow, I doubt
we would even se a pattern". This is what the lensing
actually does. It makes the pattern very difficult to spot,
but not impossible. That is why the great attractor was
not discovered until fairly recently. The flows caused
by the attractor seem to be superimposed on a larger
Hubble flow. In fact the attractor is responsible both
for the Hubble flow and for the small fluctuations that
are superimposed on it.
Another effect of the lensing is to cause some quasars
to seem to move across our field of view with superluminal
proper motions. This led Dr. Halton Arp to consider that
the quasars are really local phenomena. I would say that
the apparent superluminal motion is caused by variation
over time of the curvature of the path taken by the light
from the quasar on its way to us.
..
> I think you feel science is more certain of the models than it
> really is. There is still a lot to learn.
Has anyone told the scientists that?
Once again, I am impressed, but do you really think
that science is as uncertain of its models as you are
suggesting? Most of the "scientists" here would say
that the picture is practically complete, and it's just a
matter of crossing a few I's and dotting a few T's (sic).
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
G=EMC^2 Glazier
That means we can only guess its age.We can be sure that over 50% of the
universe's stars now exist as dark,or very dim matter. When I say dim I
could have said red glowing matter,like lumps of charcoal. To dim to be
seen by a telescope with a power a million times that of HST. 50% of
this dark matter gives off radio waves that are thousands of miles long.
This is all true because EM energies dim as to the inverse square of the
distance,and the explosion rate of space expansion,makes all this as
true as your nose on your face. Finding the limits of the universe,its
shape,and where it is taking us,will be a task for mankind thousands of
years from now. At our spacetime we should not expect to much. Best
regards Bert
George Dishman
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1027982041.5404.0...@news.demon.co.uk...
> >
> > I have seen suggests the size is much greater, probably infinite
> > but the most distant objects we have seen would 'now' be at least
> > 80 billion light years away. I have seen nothing to suggest the
> > universe is finite.
>
> The information you have seen probably implies, without
> justification, that the radius of the universe is at least equal
> to the greatest distance that we can see. This would not be
> the case in a closed universe in which light could follow
> a closed orbit multiple times before being detected.
The information I have seen is that, in a closed universe, the
light would be able to travel half the length of a closed path
in the time between bang and crunch. The information is that
the observed mean density is well below critical.
Thanks for the references - I'll check them later.
> > > of himself. Note I don't say that there are any actual mirrors, but
> > > if light can be made to follow closed orbits by gravity,
> >
> > It cannot, expect possibly as an unstable orbit at a critical
> > distance around a black hole.
>
> .. or around a universe which is in many ways like the interior
> of a black hole, i.e. which is sufficiently massive and compact
> to be closed.
>
> "Critical distance"? That only makes sense for circular orbits.
> Why does nobody consider the possibility that light needn't
> follow circular orbits? Do comets follow circular orbits?
Elliptical orbits are stable, the closed orbit round a black hole
is unstable. If it is a perfect circle at some radius R, then one
micron outside R and the photon flies off to infinity, while one
micron inside and it falls into the event horizon.
> > All the examples we see of gravitational lensing have deflections
> > which are very small.
>
> All the examples that have been *identified as such* have
> deflections that appear to be small.
>
> Suppose that two quasars on opposite sides of the sky
> were in fact different images of the same object. How would
> we determine that this was the case?
If that were the case, why do we not se some at 90 degrees,
more at 30 degrees, still more at 3 degrees and so on. There
should be a distribution of deviations of all angles. That
is not what is observed. Plot the number of occurences against
angle and it will fall very rapidly.
>It's no use comparing
> spectra or luminosity .. quasars fluctuate from day to day,
> even sometimes from minute to minute. It's only when the
> path length difference between the two images is very small,
> maybe just a couple of years different, that we can see the
> two images fluctuate in step, give or take a year or two.
> In practice this only happens when the images are very close
> together. This might mean that the deflection of both images
> is small, or it might mean that one is deflected by 23 degrees,
> say, and the other is deflected by 23.001 degrees.
In that case, I would expect to see not point sources but two
concentric extended arcs very close together. We do see
examples of that as expected.
> > If large deflections were commonplace we
> > should expect a kaliedoscope effect with the appearance of
> > galaxies being more disrupted the further away they are. I have
> > not seen any evidence for anything like that. On the scale you
> > suggest, anything beyond 1 billion light years should be
> > severly distorted. That is certainly not the case.
>
> The whole field of view can be severely distorted by
> cosmic-scale lensing, and the individual specks of galaxies
> will still look like galaxies, albeit stretched out. This stretching
> is not all that noticeable - it just makes some galaxies look more
> elliptical than they ought to, and others less elliptical than
> they ought to. It is the very *small* scale distortion, caused
> by individual galaxies, which results in gross and easily seen
> distortions of the images of individual lensed galaxies.
And I conclude larger deviations would cause greater
distortion.
> But, radio galaxies usually have jets that emerge from the
> poles, at right angles to the plane of the galaxy. Shear the
> images and the radio image will align more or less with the
> optical image instead of being at right angles to it. This is
> what is observed at great apparent distances. This, and
> a proportion of unusually elongated and misshapen galaxies,
> consistent with the images of those galaxies being sheared.
What mass distribution would cause a shear effect?
> It certainly is the case that there are spectacular examples
> of gravitational lensing resulting in multiple images of single
> galaxies, and these examples are nore noticeable at greater
> apparent distances.
Naturally, since there is a longer baseline to act over.
> > > So, we ought to see younger galaxies at greater distances.
> >
> > I believe we do see a difference in the ratio of globular
> > to elliptical galaxies though I don't know the details.
>
> Shearing and stretching distortion will tend to make globular
> galaxies look elliptical.
Yes, but it won't make it look like an "elliptical galaxy" AIUI.
>However, this effect is insignificant
> compared to the fact that globular galaxies are generally smaller
> than elliptical ones, and can't be expected to be visible over
> distances of billions of light years.
I could be wrong but I thought we saw more globulars.
> > > Instead we see, as in the title of this thread,
> > > "UNIVERSE OLDER THAN EXPECTED".
> >
> > Good, something new to learn.
>
> I'm impressed by your attitude.
>
> >
> > <snip>
> > > > The lookback time then comes from applying the
> > > > various models to figure out what the universe was like in the
> > > > past based on what we see now.
> > >
> > > What do you think we see now?
> >
> > A picture that is mostly consistent with the big bang, but
> > with too many unknowns to think we have anything like the
> > whole story.
>
> Compare that with what we ought to see now, if the
> big bang theory really was an accurate description of
> the universe.
As I say, what we see is consistent. It would be nice to
see proto-galaxies or seed structures at z>10 but we just
don't have the capability to see anything much between z=6
and the CMBR at z>1000.
> ..
> > I can see that 'cosmic lensing' might uniformly magnify
> > distant objects,
>
> "uniformly". You are hooked on the idea of homogeneity.
No, I am talking about the effect of a continuous function
such as a gravitational lens on any source which is small
in comparison to the scale of the lens.
> > and I believe that is part of some
> > current theories but I cannot see how it could create
> > the effect you describe.
>
> By inhomogeneity. By a preponderance of mass in
> one spatial direction causing a consistent lage scale
> shift of visible images across the whole of the sky.
> By this shift causing images to appear in directions and
> at apparent distances where there is no corresponding
> actual object
The idea of the effect of an inhomogenous distribution
exactly cancelling the actual inhomogeneity to give the
impression of homogeneity is not credible IMHO.
Additionally, you seem to be saying there needs to be a
large mass to create the distortion in the direction in
which there is actually a region of below average density
in order to make that region look more dense. Unless I
misunderstand you, that doesn't make sense at all.
> > > "Local" is not easy to define in a universe where the
> > > galaxies are in motion with respect to one another, but
> > > I think it is reasonable to use the great attractor as a
> > > reference point. In falling towards the attractor, our
> > > galaxy follows a trail that was blazed long ago by other
> > > similar galaxies. If such a galaxy is now closer to the
> > > attractor than we are, we can say that it once occupied
> > > the space that our galaxy now occupies. When we see
> > > distant images of that galaxy in its youth, when it was as
> > > old as our galaxy is now, we are seeing an image of the
> > > local region of space.
> >
> > No, we are seeing an image of that galaxy when it was between
> > us and the Attractor.
>
> That is one of the images that we see .. the nearest one.
> But the galaxy can emit light in other directions too, not
> just directly towards us. If this light is bent around, following
> a closed orbit, it can eventually reach us from a direction
> *opposite* to the direction of the galaxy from which it was
> emitted. We then perceive that galaxy as a distant galaxy in
> the direction of Perseus, say.
Now try to work out the mass distribution needed to do that.
It is simply not credible.
> > The Attractor was discovered by mapping
> > the flow of galaxies being drawn to it. Any significant lensing
> > as you describe would so disrupt the appearance of the flow, I
> > doubt we would even se a pattern.
>
> The effect of the lensing is to make the "Hubble Flow" seem
> to prevail over the whole of the sky, even though galaxies are
> being drawn together over a region many hundreds of millions
> of light years across. Because of the lensing, even galaxies
> which are on the other side of the attractor, being rapidly
> drawn towards it and by implication towards us, still appear
> redshifted.
They don't, they appear blue-shifted. The difference
between what is observed and the Hubble flow is generally
radially towards the location assumed to be the Attractor.
> As you say, "Any significant lensing as you describe
> would so disrupt the appearance of the flow, I doubt
> we would even se a pattern". This is what the lensing
> actually does. It makes the pattern very difficult to spot,
> but not impossible. That is why the great attractor was
> not discovered until fairly recently. The flows caused
> by the attractor seem to be superimposed on a larger
> Hubble flow. In fact the attractor is responsible both
> for the Hubble flow and for the small fluctuations that
> are superimposed on it.
Please demonstrate how that can happen:
E x A y
E is the Earth, A is the Great Attractor, galaxies at
x have higher red-shift than the Hubble flow while those
at y have less than expected. In all other directions in
the sky, galaxies at the same distance have shifts that
match the flow. What distribution of mass could cause
this effect by lensing and also explain a uniform red
shift in all directions?
> Another effect of the lensing is to cause some quasars
> to seem to move across our field of view with superluminal
> proper motions. This led Dr. Halton Arp to consider that
> the quasars are really local phenomena. I would say that
> the apparent superluminal motion is caused by variation
> over time of the curvature of the path taken by the light
> from the quasar on its way to us.
This is a well known effect and is even in the FAQs.
> > I think you feel science is more certain of the models than it
> > really is. There is still a lot to learn.
>
> Has anyone told the scientists that?
>
> Once again, I am impressed, but do you really think
> that science is as uncertain of its models as you are
> suggesting? Most of the "scientists" here would say
> that the picture is practically complete, and it's just a
> matter of crossing a few I's and dotting a few T's (sic).
Try reading up on the variety of theories being tested by
the MAP project for example. There are dozens of competing
ideas and we are a long way from knowing which is correct.
Jeff Root
>>>> but if light can be made to follow closed orbits by gravity,
>>>
>>> distance around a black hole.
>>
>> .. or around a universe which is in many ways like the interior
>> of a black hole, i.e. which is sufficiently massive and compact
>> to be closed.
>>
>> "Critical distance"? That only makes sense for circular orbits.
>> Why does nobody consider the possibility that light needn't
>> follow circular orbits? Do comets follow circular orbits?
>
> Elliptical orbits are stable, the closed orbit round a black hole
> is unstable. If it is a perfect circle at some radius R, then one
> micron outside R and the photon flies off to infinity, while one
> micron inside and it falls into the event horizon.
case of massive objects, but not in the case of photons.
Photons usually follow hyperbolic trajectories in the presence
of gravitational fields. They can't follow elliptical paths
because they don't lose speed as they rise in a gravitational
well.
>>> All the examples we see of gravitational lensing have
>>> deflections which are very small.
>>
>> All the examples that have been *identified as such* have
>> deflections that appear to be small.
>>
>> Suppose that two quasars on opposite sides of the sky
>> were in fact different images of the same object. How would
>> we determine that this was the case?
>
> If that were the case, why do we not see some at 90 degrees,
> more at 30 degrees, still more at 3 degrees and so on. There
> should be a distribution of deviations of all angles. That
> is not what is observed. Plot the number of occurences against
> angle and it will fall very rapidly.
I agree with your earlier statement that,
> in a closed universe, the light would be able to travel half the
> length of a closed path in the time between bang and crunch."
But in a steady-state universe which is closed but prevented
from collapsing by a cosmic repulsive force, light could have
plenty of time to be bent around in a big loop by the gravity
of the entire universe, not just some small part of it. In
that case, I think a secondary image of a galaxy in front of
you would most likely be visible behind you, possibly with
minimal distortion. I don't buy this scenario, but it seems
plausible at a casual look.
>> As you say, "Any significant lensing as you describe
>> would so disrupt the appearance of the flow, I doubt
>> we would even se a pattern". This is what the lensing
>> actually does. It makes the pattern very difficult to spot,
>> but not impossible. That is why the great attractor was
>> not discovered until fairly recently. The flows caused
>> by the attractor seem to be superimposed on a larger
>> Hubble flow. In fact the attractor is responsible both
>> for the Hubble flow and for the small fluctuations that
>> are superimposed on it.
>
> Please demonstrate how that can happen:
>
> E x A y
>
> E is the Earth, A is the Great Attractor, galaxies at
> x have higher red-shift than the Hubble flow while those
> at y have less than expected. In all other directions in
> the sky, galaxies at the same distance have shifts that
> match the flow. What distribution of mass could cause
> this effect by lensing and also explain a uniform red
> shift in all directions?
Light from galaxies at y might come to us by a path which
starts off to the right, then wraps around and approaches
Earth from the left. You would see these galaxies in the
opposite direction from the attrctor. A problem with this
is that it would also be true of galaxies at x, which would
appear to be even more distant, but blue-shifted.
>>> I think you feel science is more certain of the models than it
>>> really is. There is still a lot to learn.
>>
>> Has anyone told the scientists that?
>>
>> Once again, I am impressed, but do you really think
>> that science is as uncertain of its models as you are
>> suggesting? Most of the "scientists" here would say
>> that the picture is practically complete, and it's just a
>> matter of crossing a few I's and dotting a few T's (sic).
Martin apparently believes that scientists are as certain of
their speculations as Martin is of his.
-- Jeff, in Minneapolis
.
Martin Gradwell
Jeff Root <je...@freemars.org> wrote in message
news:f0b30c00.02073...@posting.google.com...
> George Dishman replied to Martin Gradwell:
> > Elliptical orbits are stable, the closed orbit round a black hole
> > is unstable. If it is a perfect circle at some radius R, then one
> > micron outside R and the photon flies off to infinity, while one
> > micron inside and it falls into the event horizon.
>
> You could have said that elliptical orbits are stable in the
> case of massive objects, but not in the case of photons.
> Photons usually follow hyperbolic trajectories in the presence
> of gravitational fields. They can't follow elliptical paths
> because they don't lose speed as they rise in a gravitational
> well.
Photons are accelerated just as much by a gravitational
well as any freely falling matter is. Einstein's elevator gedanken
illustrates this. Einstein's geometrical interpretation of this
situation asserts that neither light nor freely falling matter
are accelerated at all in such a field - both follow geodesics,
which are "maximally straight". This does not stop thrown
balls following "maximally straight" approximately parabolic
courses, and comets following elliptical orbits.
The depth of the earth's surface in the universal
gravitational well is the only depth at which careful
measurement of the speed of light has taken place.
Logic / Occam's razor might suggest that light will
accelerate as it falls deeper into a gravitational well,
because that is what happens to everything else.
But we don't need no steenking logic. ;-)
The speed of light is fixed everywhere, not because
it has been measured and found to be so, but because
it has been defined that way. If it seems to vary, we
"know" that this is because our measuring rods are varying
in length, or our clocks are keeping different times, in a
spacetime that is non-Euclidean. In this spacetime reference
bodies can be almost infinitely flexible, making them more
like reference molluscs, as Einstein said.
We could make the speed of anything else fixed,
by the choice of an appropriate coordinate system.
For instance, a ball thrown upwards could have a
fixed speed if we measured that speed using rulers
which are shorter at greater heights. The ball moves
upwards at a fixed speed, until it seems to bounce
off an invisible ceiling, and then it moves downwards,
again at a fixed speed, according to our measurements.
Why not?
Photons follow hyperbolic trajectories because
they are *fast*. But Newton showed that in the
vicinity of a sufficiently massive gravitating body
that hyperbola would be replaced by an ellipse.
That is what happens for anything else. Newton
assumed that light would be affected in exactly the
same way as matter, and Einstein himself showed
that this was a reasonable assumption.
Don't you think it's remarkable that photons "don't
lose speed as they rise in a gravitational well", but
they are just as incapable of escaping from a black
hole as things that do lose speed?
..
> I agree with your [i.e. George's] earlier statement that,
>
> > in a closed universe, the light would be able to travel half the
> > length of a closed path in the time between bang and crunch."
>
> But in a steady-state universe which is closed but prevented
> from collapsing by a cosmic repulsive force, light could have
> plenty of time to be bent around in a big loop by the gravity
> of the entire universe, not just some small part of it. In
> that case, I think a secondary image of a galaxy in front of
> you would most likely be visible behind you, possibly with
> minimal distortion. I don't buy this scenario, but it seems
> plausible at a casual look.
You've *almost* got it, but you don't need the cosmic
repulsive force. Instead, you get something a lot more
like the actual observed universe if you just let it collapse.
The collapsing matter eventaully bunches together, until
there is eventually a central concentration of mass (great
attractor, or singularity) which is more massive than
anything else in the universe. Galaxies accelerate as they
fall towards it, so that those closest to the singularity
accelerate away from those further away. This gives the
appearance of an accelerating expansion, at least in certain
directions and at certain distances.
Lensing effects cause this universe to appear larger than
it actually is, and also to be uniformly expanding, at large
apparent distances. All you then need to round it off is a
recycling mechanism. The central attractor periodically
flares up, producing vast outpourings of energy and high
speed subatomic particles. These eventually condense into
gas clouds at the edge of the universe, which further
condense into galaxies, and the cycle repeats. So, even
though each individual galaxy has a finite lifetime, the
whole assemblage can continue to exist indefinitely.
>
> >> As you say, "Any significant lensing as you describe
> >> would so disrupt the appearance of the flow, I doubt
> >> we would even se a pattern". This is what the lensing
> >> actually does. It makes the pattern very difficult to spot,
> >> but not impossible. That is why the great attractor was
> >> not discovered until fairly recently. The flows caused
> >> by the attractor seem to be superimposed on a larger
> >> Hubble flow. In fact the attractor is responsible both
> >> for the Hubble flow and for the small fluctuations that
> >> are superimposed on it.
> >
> > Please demonstrate how that can happen:
> >
> > E x A y
> >
> > E is the Earth, A is the Great Attractor, galaxies at
> > x have higher red-shift than the Hubble flow while those
> > at y have less than expected. In all other directions in
> > the sky, galaxies at the same distance have shifts that
> > match the flow. What distribution of mass could cause
> > this effect by lensing and also explain a uniform red
> > shift in all directions?
>
> Light from galaxies at y might come to us by a path which
> starts off to the right, then wraps around and approaches
> Earth from the left. You would see these galaxies in the
> opposite direction from the attrctor.
Ligh which starts off to the right from y will follow (according
to my reckoning) a very narrow elliptical path, which will
eventually take it very close to the attractor A. There it will
be slingshotted around through a very tight angle, so that it
is unlikely to end up near E. We are more likely to see light
that goes upwards from y and curves around, eventually moving
downwards towards E, so that y appears from earth to be at
right angles to the direction of the attractor, or thereabouts.
The exact course taken by light in travelling from y to E
depends on the mass of the attractor and the exact distances
of y and E from it. It will also depend to some extent on the
distribution of lesser masses in the vicinity of the light's path.
If light does take the "up then down" path, this does not
preclude it also taking other paths. There will in general be
multiple distant images of any galaxy that existed long ago,
formed by light which has followed many different paths.
> A problem with this
> is that it would also be true of galaxies at x, which would
> appear to be even more distant, but blue-shifted.
Light from x which initially moves to the right will pass very
close to A, where there is a very dense collection of large
galaxies, making that region of space almost opaque. It will
then be slingshotted around the singularity located at the
attractor, and head towards us, again running the gauntlet
of that dense collection of galaxies. If it reaches us without
being intercepted, its direction will have been slightly randomised,
so that it will not form a clear image of a blueshifted galaxy.
As it happens, the attractor is hidden by the plane of our
galaxy, but even if it wasn't we would not see any clear
images of blueshifted galaxies in its vicinity. Even if we could
see them, we would think that they were on the other side
of the attractor (or on the other side of some more distant
attractor, which is really an image of the local attractor) and
so we wouldn't be all that surprised by the blueshift.
This is all very tricky to explain using words. I think
the diagrams on my website will make it clearer.
..
> >> Once again, I am impressed, but do you really think
> >> that science is as uncertain of its models as you are
> >> suggesting? Most of the "scientists" here would say
> >> that the picture is practically complete, and it's just a
> >> matter of crossing a few I's and dotting a few T's (sic).
>
> Martin apparently believes that scientists are as certain of
> their speculations as Martin is of his.
Yes. I think my ideas can explain so many disparate
phenomena, most of which are *not* explained by more
conventional models, that I can justifiably have some
confidence in them. The fact that I have never seen a
convincing refutation of them despite repeated wide-ranging
requests for one helps too, as does the fact that many of the
ideas that were once unique to me (as far as I can tell) are
now becoming widely accepted, though not as a complete
integrated package.
When I began, I was told that if there was some
supermassive object drawing in galaxies over a vast
area, then surely somebody would have noticed it.
Instead, all the books made it clear that the universe
was homogeneous, with only minor local fluctuations.
Also, an apparent expansion that was really caused
by collapse would seem to accelerate, and everyone
knew that the expansion was really slowing down.
The only question still faced by science was whether
this slowing down was enough to ensure an eventual
recollapse or not, and even this question was being
answered with some regularity, though not always
with the same answer. There was no doubt whatsoever
about the actuality of deceleration, and this was the
strongest argument that I encountered against my ideas.
Also, if I didn't believe in my "speculations", I can be
fairly certain that nobody else would either. And I think
it would be a great pity if nobody at all believed in them,
because I find them fascinating.
>
> -- Jeff, in Minneapolis
George Dishman
"Jeff Root" <je...@freemars.org> wrote in message
news:f0b30c00.02073...@posting.google.com...
> George Dishman replied to Martin Gradwell:
>
> > Elliptical orbits are stable, the closed orbit round a black hole
> > is unstable. If it is a perfect circle at some radius R, then one
> > micron outside R and the photon flies off to infinity, while one
> > micron inside and it falls into the event horizon.
>
> You could have said that elliptical orbits are stable in the
> case of massive objects, but not in the case of photons.
True, but that would be just an assertion that I wouldn't accept
from others. I try to explain my statements so that, if I am
wrong, someone more knowledgeable can correct it.
> Photons usually follow hyperbolic trajectories in the presence
> of gravitational fields. They can't follow elliptical paths
> because they don't lose speed as they rise in a gravitational
> well.
Again that is true. Photons do not accelerate subject to a
1/r^2 force which is what is required for an elliptical orbit.
there are many ways to consider this but the basic fact is that
a nmassive body if displaced away from the larger object will
move back whereas a photon will move further away. The key
fact is that it is an unstable configuration.
> I agree with your earlier statement that,
>
> > in a closed universe, the light would be able to travel half the
> > length of a closed path in the time between bang and crunch."
>
> But in a steady-state universe which is closed but prevented
> from collapsing by a cosmic repulsive force, light could have
That was an early view, and I think part of Einstein's thinking
in including the Cosmological Constant, but has since been shown
to be unstable (more distant objects would accelerate away while
nearer ones would clump together).
> plenty of time to be bent around in a big loop by the gravity
> of the entire universe, not just some small part of it. In
> that case, I think a secondary image of a galaxy in front of
> you would most likely be visible behind you, possibly with
> minimal distortion. I don't buy this scenario, but it seems
> plausible at a casual look.
The devil is in the details as they say.
> >> As you say, "Any significant lensing as you describe
> >> would so disrupt the appearance of the flow, I doubt
> >> we would even se a pattern". This is what the lensing
> >> actually does. It makes the pattern very difficult to spot,
> >> but not impossible. That is why the great attractor was
> >> not discovered until fairly recently. The flows caused
> >> by the attractor seem to be superimposed on a larger
> >> Hubble flow. In fact the attractor is responsible both
> >> for the Hubble flow and for the small fluctuations that
> >> are superimposed on it.
> >
> > Please demonstrate how that can happen:
> >
> > E x A y
> >
> > E is the Earth, A is the Great Attractor, galaxies at
> > x have higher red-shift than the Hubble flow while those
> > at y have less than expected. In all other directions in
> > the sky, galaxies at the same distance have shifts that
> > match the flow. What distribution of mass could cause
> > this effect by lensing and also explain a uniform red
> > shift in all directions?
>
> Light from galaxies at y might come to us by a path which
> starts off to the right, then wraps around and approaches
> Earth from the left.
In which case we would see it to the left. What the diagram
is meant to show is that two galaxies which are seen almost
in line with the Great Attractor but at different distances
have red shifts that are a combination of the Hubble flow
and a term pointing radially towards the location of the
attractor.
>You would see these galaxies in the
> opposite direction from the attrctor. A problem with this
> is that it would also be true of galaxies at x, which would
> appear to be even more distant, but blue-shifted.
What you say also further illustrates my point (though it
has since been snipped), the simple pattern we see would
be scattered over the sky by such extreme effects over
these short ranges. That just isn't the case.
> Martin apparently believes that scientists are as certain of
> their speculations as Martin is of his.
It makes it easier to ignore them.
George Dishman
distance in the linear Hubble equation so I'm going to leave
the rest of what you said to Jeff as we are starting to drift
into other areas. I will just note this though:
"Martin Gradwell" <mtgra...@btinternet.com> wrote in message
news:ai9947$7t4$1...@news7.svr.pol.co.uk...
>
> > George Dishman replied to Martin Gradwell:
> ..
> > >> ... The flows caused
> > >> by the attractor seem to be superimposed on a larger
> > >> Hubble flow. In fact the attractor is responsible both
> > >> for the Hubble flow and for the small fluctuations that
> > >> are superimposed on it.
> > >
> > > Please demonstrate how that can happen:
> > >
> > > E x A y
> > >
> > > E is the Earth, A is the Great Attractor, galaxies at
> > > x have higher red-shift than the Hubble flow while those
> > > at y have less than expected. In all other directions in
> > > the sky, galaxies at the same distance have shifts that
> > > match the flow. What distribution of mass could cause
> > > this effect by lensing and also explain a uniform red
> > > shift in all directions?
>
> Light from x which initially moves to the right will pass very
> close to A, where there is a very dense collection of large
> galaxies, making that region of space almost opaque. It will
> then be slingshotted around the singularity located at the
> attractor, and head towards us, again running the gauntlet
> of that dense collection of galaxies. If it reaches us without
> being intercepted, its direction will have been slightly randomised,
> so that it will not form a clear image of a blueshifted galaxy.
That's right, and in looking at alternatives to the big bang,
one of the tests applied is for blurring of distant objects.
For example one suggestion was Compton scattering as an
explanation for the red-shift. Very tight limits have been
put on any blurring and it is nothing like what would
result from the scenario you describe.
George Dishman
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1027982041.5404.0...@news.demon.co.uk...
> >
> > distant objects,
>
> "uniformly". You are hooked on the idea of homogeneity.
This is the sort of thing I meant:
"habshi" <hab...@anony.com> wrote in message
news:3d47b6d9...@news.clara.net...
>
> The cluster acts as a powerful gravitational lens, magnifying distant
> objects and allowing the scientists to probe how distant galaxies
> assembled at very early times. Gravitational lensing, a dramatic
> feature of Einstein's theory of general relativity, means that a
> massive object in the foreground bends the light rays radiating from
> one in the background because mass curves space. As a result, an
> object behind a massive foreground galaxy cluster like Abell 2218 can
> look much brighter because the foreground object has bent additional
> photons toward Earth, in much the same way that glass lenses in
> binoculars will bend more photons toward the eyes. In the case of the
> system detected by Ellis and co-workers, the effect makes the image at
> least 30 times brighter than would be the case if the Abell 2218
> cluster were not in the foreground.
The effect is like looking at a pin-point source through a
goldfish bowl while in your concept it would be like seeing
a floodlight through frosted glass.
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:ai5vg6$cjm$1...@newsg4.svr.pol.co.uk...
> > The information you have seen probably implies, without
> > justification, that the radius of the universe is at least equal
> > to the greatest distance that we can see. This would not be
> > the case in a closed universe in which light could follow
> > a closed orbit multiple times before being detected.
>
> The information I have seen is that, in a closed universe, the
> light would be able to travel half the length of a closed path
> in the time between bang and crunch.
I've discussed this in with you in the past - see
http://groups.google.com/groups?selm=a6ggms%2478n%241%40newsg1.svr.pol.co.uk
Here's a small excerpt from that:
"The reasons why light cannot come around for a
second or third pass are tied in with the assumed
homogeneity of the universe. IMO the universe is
not homogeneous, and contains concentrations of
mass sufficiently large to draw light into closed orbits.
In an absolutely homogeneous universe light can
only approach an observer from the direction of the
source of the light. Given inhomogeneity, this ceases
to be true."
I've also said more about this in a reply to Jeff Root,
in this thread.
> The information is that
> the observed mean density is well below critical.
To me, the notion of "critical density" can only
have meaning in a universe which is expanding
at a decelerating rate. When the apparent expansion
is accelerating, what can critical density mean?
..
> Elliptical orbits are stable, the closed orbit round a black hole
> is unstable. If it is a perfect circle at some radius R, then one
> micron outside R and the photon flies off to infinity, while one
> micron inside and it falls into the event horizon.
Again I've dealt with this in the reply to Jeff Root.
..
> > Suppose that two quasars on opposite sides of the sky
> > were in fact different images of the same object. How would
> > we determine that this was the case?
>
> If that were the case, why do we not se some at 90 degrees,
> more at 30 degrees, still more at 3 degrees and so on. There
> should be a distribution of deviations of all angles. That
> is not what is observed.
Isn't it?
> Plot the number of occurences against
> angle and it will fall very rapidly.
We can only be sure that two images are of the same
quasar if they are close together. But, again, how do
we know that quasars on opposite sides of the sky
aren't actually the same quasar?
..
> > The whole field of view can be severely distorted by
> > cosmic-scale lensing, and the individual specks of galaxies
> > will still look like galaxies, albeit stretched out. This stretching
> > is not all that noticeable - it just makes some galaxies look more
> > elliptical than they ought to, and others less elliptical than
> > they ought to. It is the very *small* scale distortion, caused
> > by individual galaxies, which results in gross and easily seen
> > distortions of the images of individual lensed galaxies.
>
> And I conclude larger deviations would cause greater
> distortion.
Consider a large glass magifying glass, compared with
a tiny cheap plasticky one, of the sort which might fall
out of a cracker. Which causes the greater distortion
of tiny parts of the field of view?
Even when the large glass is used to produce excessive
magnification, so that much of the field of view is grossly
distorted, tiny parts of the field are still recognisable.
Looking at a newspaper photograph you still see dots,
and most of the dots still look round(ish). They just don't
align themselves in the straight lines that you would expect
if there was no distortion.
>
> > But, radio galaxies usually have jets that emerge from the
> > poles, at right angles to the plane of the galaxy. Shear the
> > images and the radio image will align more or less with the
> > optical image instead of being at right angles to it. This is
> > what is observed at great apparent distances. This, and
> > a proportion of unusually elongated and misshapen galaxies,
> > consistent with the images of those galaxies being sheared.
>
> What mass distribution would cause a shear effect?
If an image has already been stretched out by one lens,
and then just one end of this stretched image is stretched
in another direction by a second lens, there will be a
shearing effect. But even a simple stretch effect from
a single lensing will cause lines that are really at right angles
to appear more or less aligned. Imagine that the x below
represents a distant galaxy image. One oblique stroke
represents the optical image. The other represents the
radio image of the same galaxy.
x
Now imagine it stretched out horizontally
==x==
or vertically
| |
| |
x
| |
| |
I have to use not-very-good ascii representations
because I can't actually type a very wide or very tall x,
but I hope you get the idea.
>
> > It certainly is the case that there are spectacular examples
> > of gravitational lensing resulting in multiple images of single
> > galaxies, and these examples are nore noticeable at greater
> > apparent distances.
>
> Naturally, since there is a longer baseline to act over.
>
> > > > So, we ought to see younger galaxies at greater distances.
> > >
> > > I believe we do see a difference in the ratio of globular
> > > to elliptical galaxies though I don't know the details.
> >
> > Shearing and stretching distortion will tend to make globular
> > galaxies look elliptical.
>
> Yes, but it won't make it look like an "elliptical galaxy" AIUI.
There's a fairly extreme example at
http://casa.colorado.edu/~raosten/project/cosmo.html
- here, it is obvious that the long, thin. slightly curved
streaks are lensed. but what about the other galaxies
is the picture. Are the round ones *really* round?
Are the elliptical ones *really* elliptical? How much
have their images been stretched or squashed?
..
> As I say, what we see is consistent. It would be nice to
> see proto-galaxies or seed structures at z>10 but we just
> don't have the capability to see anything much between z=6
> and the CMBR at z>1000.
Is the CMBR really at z>1000? If so, how does it manage
to pass through so many clouds of hyrogen on its way to us,
and arrive unscathed? (We know there's lots of clouds of
hydrogen in every direction, especially at high redshift,
because of the Lyman alpha forest).
>
> > ..
> > > I can see that 'cosmic lensing' might uniformly magnify
> > > distant objects,
> >
> > "uniformly". You are hooked on the idea of homogeneity.
>
> No, I am talking about the effect of a continuous function
> such as a gravitational lens on any source which is small
> in comparison to the scale of the lens.
Take a look at http://www.btinternet.com/~mtgradwell/grid3.jpg
to see what (according to my calculations) a continuous
function such as a cosmic-scale gravitational lens can do to
a rectangular grid.
http://www.btinternet.com/~mtgradwell/grid3src.jpg
is the rectangular grid.
..
> The idea of the effect of an inhomogenous distribution
> exactly cancelling the actual inhomogeneity to give the
> impression of homogeneity is not credible IMHO.
Not *exactly* cancelling. I would expect some quantisation
of redshift. I would expect more quantisation - a more
pronounced alternation of "sheets of galaxies" and "bubble
like voids" in some directions than in others. Only at
very high z would the homogeneity and isotropy become
almost total. I'd expect something like the diagrams
on my website to be observed in practice. In other words,
I'd expect the "Great Wall", the "Geller-Huchra wedge", the
"Southern Wall, the great curving sweep of the Perseus-Pisces
supercluster, and much, much more.
>
> Additionally, you seem to be saying there needs to be a
> large mass to create the distortion in the direction in
> which there is actually a region of below average density
> in order to make that region look more dense. Unless I
> misunderstand you, that doesn't make sense at all.
In every direction, beyond a certain distance, I'm saying
that there are no galaxies at all. So, for us to see galaxies
in every directions at those great distances there has to be
distortion, and this distortion is created by a large mass.
..
> > That is one of the images that we see .. the nearest one.
> > But the galaxy can emit light in other directions too, not
> > just directly towards us. If this light is bent around, following
> > a closed orbit, it can eventually reach us from a direction
> > *opposite* to the direction of the galaxy from which it was
> > emitted. We then perceive that galaxy as a distant galaxy in
> > the direction of Perseus, say.
>
> Now try to work out the mass distribution needed to do that.
> It is simply not credible.
Why not? Because it is highly inhomogeneous, with a
pronounced concentration of mass at the great attractor?
But we know this is the case. Even people who think
the universe is homogeneous at larger scales acknowledge
that there is a great concentration of mass at the great
attractor. It isn't called that for nothing.
>
> > > The Attractor was discovered by mapping
> > > the flow of galaxies being drawn to it. Any significant lensing
> > > as you describe would so disrupt the appearance of the flow, I
> > > doubt we would even se a pattern.
> >
> > The effect of the lensing is to make the "Hubble Flow" seem
> > to prevail over the whole of the sky, even though galaxies are
> > being drawn together over a region many hundreds of millions
> > of light years across. Because of the lensing, even galaxies
> > which are on the other side of the attractor, being rapidly
> > drawn towards it and by implication towards us, still appear
> > redshifted.
>
> They don't, they appear blue-shifted. The difference
> between what is observed and the Hubble flow is generally
> radially towards the location assumed to be the Attractor.
And it is smaller than the Hubble flow on which it is
superimposed. Galaxies on the far side of the attractor
are redshifted, but apparently less so than would be the
case if there was no atttractor there. See e.g.
http://zebu.uoregon.edu/~imamura/123/images/great.gif
and the bottom part of
http://zebu.uoregon.edu/~imamura/123/lecture-6/dynamic2.html
You will find many sites that inform you that there
are only a handful of blueshifted galaxies, and they
are all members of the local group, such as Andromeda
and the lesser Magellanic cloud.
I do have a vague recollection of once seeing a
report of a distant blueshifted galaxy, but if there
was such a report, and it's not just a figment of my
imagination, I can't find it now.
..
> Please demonstrate how that can happen:
>
> E x A y
>
> E is the Earth, A is the Great Attractor, galaxies at
> x have higher red-shift than the Hubble flow while those
> at y have less than expected. ...
This again is something I've dealt with in the
reply to Jeff Root.
..
> Try reading up on the variety of theories being tested by
> the MAP project for example. There are dozens of competing
> ideas and we are a long way from knowing which is correct.
Thanks. I'll look it up.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
Martin Gradwell
> [Newsgroups trimmed]
>
> "Jeff Root" <je...@freemars.org> wrote in message
> news:f0b30c00.02073...@posting.google.com...
> > Martin apparently believes that scientists are as certain of
> > their speculations as Martin is of his.
>
> It makes it easier to ignore them.
Is that justified? These conversations don't peter out
because I ignore anything that others are saying. On the
contrary, I try to deal with any valid points that anybody
might raise, and that are directed at me. It is others who
eventually discontinue the thread (and I don't mind that,
I'm not saying that they should continue even if they
don't want to, or if they can't afford the time).
Actually I can't afford the time either - after all,
it's not as if my ideas are likely to become widely
adopted as a result of my efforts - but still I try to
deal with every point, because I don't want anyone
to say there are obvious flaws in my theories that
have been pointed out to me and that I have failed
to address. I want people to see that I can cope with
any objection that they might raise.
Perhaps you mean that I ignore ideas which are
different from my own, such as mainstream ideas,
but my ideas are a specific response to flaws that
I perceive in more mainstream theories. I don't see
how I can be said to be ignoring them.
There are lots of ideas that I don't know about,
but it isn't for want of trying. There are only 24
hours in a day.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
Martin Gradwell
> Martin, I only intended to appraise you of the nature of the
> distance in the linear Hubble equation so I'm going to leave
> the rest of what you said to Jeff as we are starting to drift
> into other areas.
That's OK. You've been a great help. Thanks.
> I will just note this though:
...
> > > > E x A y
> > > >
> > > > E is the Earth, A is the Great Attractor, galaxies at
> > > > x have higher red-shift than the Hubble flow while those
> > > > at y have less than expected
...
> > Light from x which initially moves to the right will pass very
> > close to A, where there is a very dense collection of large
> > galaxies, making that region of space almost opaque. It will
> > then be slingshotted around the singularity located at the
> > attractor, and head towards us, again running the gauntlet
> > of that dense collection of galaxies. If it reaches us without
> > being intercepted, its direction will have been slightly randomised,
> > so that it will not form a clear image of a blueshifted galaxy.
>
> That's right, and in looking at alternatives to the big bang,
> one of the tests applied is for blurring of distant objects.
> For example one suggestion was Compton scattering as an
> explanation for the red-shift. Very tight limits have been
> put on any blurring and it is nothing like what would
> result from the scenario you describe.
That was for one particular direction - for light passing
very close to the great attractor, and very close to the
dense collection of galaxies that congregate in its vicinity.
I'm not saying that there's a similar degree of blurring in
every spatial direction.
If you look at one of the diagrams on my website, e.g.
http://www.btinternet.com/~mtgradwell/universe3-75.jpg
the chaotic wedge-shaped regions to the left and
the right represent regions which are effectively hidden
from view behind clusters of galaxies that are dense
enough to be opaque; but in other directions the view
is clear enough.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
Martin Gradwell
I'm not saying that cosmic-scale lensing is the same as a
lot of tiny lenses all operating individually, like frosted glass.
There are some tiny lenses, and in some directions they
congregate thickly enough to obscure the view beyond
them, but most of the cosmic lensing is caused by the great
preponderance of matter at the great attractor acting as a
single giant lens. This causes all of the light in the universe
to follow smoothly curving orbits, except in the vicinity of
dense clusters of galaxies.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinernet.com
http://www.btinternet.com/~mtgradwell/
Steve Carlip
> "Looking further into space, at a distance of perhaps 350
> million light years, Margaret Geller and John Huchra of the
> Harvard-Smithsonian center for Astrophysics have discovered
> a giant sheet of galaxies - the _Great Wall_ - which stretches
> more than 500 million light years across the sky".
> - from "The inflationary universe" by Alan H. Guth, p214.
> How big does a structure have to be before you will
> consider it big? 500 million light years across is even
> bigger than Texas. That is *big*!
About 60 Mpc. See Kurukawa et al, Astron. And Astrophys. 370
(2001) 358 for a nice recent study of galaxy-galaxy correlation
functions. If you look at Table 1, you'll find a summary of a
bunch of other results, which you can follow up.
>> That is of course true at the scale of
>> galaxies and groups but on very large scales there
>> seems to be no such structure.
> For "no such", read "such a". Except in regions more
> than a billion light years across.
More like a few hundred million light years.
Steve Carlip
Martin Gradwell
Steve Carlip <car...@dirac.ucdavis.edu> wrote in message
news:ai9sic$cfm$1...@woodrow.ucdavis.edu...
Thanks.
G=EMC^2 Glazier
thinking of the universe as a continuos entity. His GR did not predict
a BB,it did however predict through its math. a BH. QM
theory is best for the BB,and that gets the universe started in the
right direction.,and after that GR takes over,so that gravity can evolve
everything one second after the BB. We can bring everything
right up to now,and make the universe continuos by the use of BH to
create billions of mini-bangs within the universe. Einstein could live
with mini-bangs for GR predicts them. Bert
Steve Carlip
> Is the CMBR really at z>1000? If so, how does it manage
> to pass through so many clouds of hyrogen on its way to us,
> and arrive unscathed?
That depends on your definition of ``unscathed.'' The CMBR
*is* affected as it passes through clouds of ionized hydrogen:
it's subject to Compton scattering. This typically changes a
photon's energy by about .05%.
Of course, this is only relevant after a significant amount of
hydrogen has been ionized.
> (We know there's lots of clouds of
> hydrogen in every direction, especially at high redshift,
> because of the Lyman alpha forest).
Right. The Lyman alpha transition is 1.6 eV. A typical CMBR
photon has an energy on the order of 10^-3 to 10^-4 eV. How,
exactly, do you expect it to be affected by neutral hydrogen?
If you want to look for effects of neutral matter on the CMBR,
you'll have to look for very low-energy transitions: see, e.g.,
astro-ph/0012222 for an observation of this very, very small
effect, from fine structure transitions in neutral hydrogen.
(The observation, incidentally, gave a very nice confirmation
that the CMBR temperature varies with red shift exactly as
predicted by the big bang model.)
Steve Carlip
Jeff Root
>> George Dishman replied to Martin Gradwell: ..
>>> Elliptical orbits are stable, the closed orbit round a black hole
>>> is unstable. If it is a perfect circle at some radius R, then one
>>> micron outside R and the photon flies off to infinity, while one
>>> micron inside and it falls into the event horizon.
>>
>> You could have said that elliptical orbits are stable in the
>> case of massive objects, but not in the case of photons.
>> Photons usually follow hyperbolic trajectories in the presence
>> of gravitational fields. They can't follow elliptical paths
>> because they don't lose speed as they rise in a gravitational
>> well.
> Don't you think it's remarkable that photons "don't
> lose speed as they rise in a gravitational well", but
> they are just as incapable of escaping from a black
> hole as things that do lose speed?
> Also, if I didn't believe in my "speculations", I can be
> fairly certain that nobody else would either. And I think
> it would be a great pity if nobody at all believed in them,
> because I find them fascinating.
truth of the speculations. Sometimes I'm surprised to learn
that my speculations were correct. But believing in the truth
of a speculation which contradicts observations is a bad sign.
I recently heard (on BBC radio) a wonderful expression which
describes this: "The triumph of hope over experience."
Martin Gradwell
..
> Martin Gradwell replied (in small part) to Jeff Root:
>
> > Don't you think it's remarkable that photons "don't
> > lose speed as they rise in a gravitational well", but
> > they are just as incapable of escaping from a black
> > hole as things that do lose speed?
>
> Yes. That's part of what makes black holes so fascinating.
But, nobody on the outside of a black hole could ever
observe the photons which fail to emerge from it. Nobody
could see these photons failing to lose speed and yet also
failing to escape. Their speed is fixed, not because there
is any observation evidence that this is the case, but
because that is how we have defined it to be.
Even if someone were somehow to cross the event
horizon of a black hole (and they'd have to find it first,
and devise some way of knowing that they had crossed
the horizon when there is no actual detectable event that
takes place at the so-called "event horizon"), There is no
way they could pass on what they learn to anyone who
remains outside. So, the interior of a black hole is
the ultimate in untestable physics, except to observers
who all happen to be inside one.
> > Also, if I didn't believe in my "speculations", I can be
> > fairly certain that nobody else would either. And I think
> > it would be a great pity if nobody at all believed in them,
> > because I find them fascinating.
>
> I speculate about a lot of things without believing in the
> truth of the speculations. Sometimes I'm surprised to learn
> that my speculations were correct. But believing in the truth
> of a speculation which contradicts observations is a bad sign.
Yes. I would never do that. That is why I had to come
up with my own set of speculations, instead of accepting
the commonly accepted set.
> I recently heard (on BBC radio) a wonderful expression which
> describes this: "The triumph of hope over experience."
Did the programme have a wonderful expression
describing those who believe in speculations which
can never be contradicted by observations because
they are, by definition, untestable?
Martin Gradwell
subject matter is drifting. MG)
Steve Carlip <car...@dirac.ucdavis.edu> wrote in message
news:ai9v0f$cfm$2...@woodrow.ucdavis.edu...
> In sci.astro Martin Gradwell <mtgra...@btinternet.com> wrote:
>
> > Is the CMBR really at z>1000? If so, how does it manage
> > to pass through so many clouds of hyrogen on its way to us,
> > and arrive unscathed?
>
> That depends on your definition of ``unscathed.'' The CMBR
> *is* affected as it passes through clouds of ionized hydrogen:
> it's subject to Compton scattering. This typically changes a
> photon's energy by about .05%.
And if the CMBR were to pass through a *lot* of such
clouds, what distribution of energies would you expect
to see as a result?
>
> Of course, this is only relevant after a significant amount of
> hydrogen has been ionized.
>
> > (We know there's lots of clouds of
> > hydrogen in every direction, especially at high redshift,
> > because of the Lyman alpha forest).
>
> Right. The Lyman alpha transition is 1.6 eV. A typical CMBR
> photon has an energy on the order of 10^-3 to 10^-4 eV. How,
> exactly, do you expect it to be affected by neutral hydrogen?
Very little, except where it encounters an atom or molecule
that is _almost_ ionized, so that the allowed energy bands are
very close together. Such atoms/molecules might be rare in
a cloud of un-ionized hydrogen.
But the fact that we see Lyman alpha transitions in Lyman
alpha clouds shows that they are irradiated by high energy
photons, which implies to me that they consist of a mixture
of ionized and un-ionized hydrogen. And when these transitions
are so strong that we can detect them in light that has been
travelling for billions of years, this suggests that there is a *lot*
of ionization in the clouds. As much as can be produced by
all the outpourings of all the quasars that we can see, in fact.
> If you want to look for effects of neutral matter on the CMBR,
> you'll have to look for very low-energy transitions: see, e.g.,
> astro-ph/0012222 for an observation of this very, very small
> effect, from fine structure transitions in neutral hydrogen.
> (The observation, incidentally, gave a very nice confirmation
> that the CMBR temperature varies with red shift exactly as
> predicted by the big bang model.)
>
> Steve Carlip
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
Martin Gradwell
..
> Try reading up on the variety of theories being tested by
> the MAP project for example. There are dozens of competing
> ideas and we are a long way from knowing which is correct.
Looking at the MAP site, http://map.gsfc.nasa.gov/
The big bang is a given, which is not even slightly questioned
except once, on the Uni_101age page (see below).
There is no mention of any known viable alternative.
At the top of the first page, "This map of the remnant heat
*from the big bang* will provide answers to fundamental
questions about the origin and fate of our universe."
(My emphasis). There are similar sentiments expressed
throughout the site. You can have your big bang with inflation,
bb with quintessence, bb with a cosmological constant, bb
with dark matter, or with dark energy, or you can have bb
and chips, or bb with egg and chips, or bb and bb, or ...
All of these "competing ideas" are different attempts to
shore up one single flawed idea.
on the http://map.gsfc.nasa.gov/m_uni/uni_101age.html
page, it says
"If the expansion age measured by MAP is smaller
than the oldest globular clusters, then there is something
fundamentally wrong about either the Big Bang theory
or the theory of stellar evolution. Either way, astronomers
will have to rethink many of their cherished ideas."
Yes, but those astronomers won't even have any
idea of where to start, until one of them comes up
out of the blue with the startling idea that the universe
might actually be collapsing, not expanding.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
George Dishman
No, I am. Look at the Abell 2218 picture you posted and you will
see many small arcs within the group caused by individual galaxies.
Take that to an extreme and you will get a frosted glass effect
with large numbers of arcs filling the picture. Now you also wrote:
"Martin Gradwell" <mtgra...@btinternet.com> wrote in message
news:ai9rpq$bpu$1...@newsg2.svr.pol.co.uk...
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1028143822.20954....@news.demon.co.uk...
> ...
> > > > > E x A y
> > > > >
> > > > > E is the Earth, A is the Great Attractor, galaxies at
> > > > > x have higher red-shift than the Hubble flow while those
> > > > > at y have less than expected
> ...
> > > Light from x which initially moves to the right will pass very
> > > close to A, where there is a very dense collection of large
> > > galaxies, making that region of space almost opaque. It will
> > > then be slingshotted around the singularity located at the
> > > attractor, and head towards us, again running the gauntlet
> > > of that dense collection of galaxies. If it reaches us without
> > > being intercepted, its direction will have been slightly randomised,
> > > so that it will not form a clear image of a blueshifted galaxy.
If the light from x to A reaches E, it has been turned through
180 degrees by the singularity so the distrion is extreme, and
then it runs "the gauntlet of that dense collection of galaxies".
That gives me the feeling that we would see the returning light
through the frosted effect of the group.
What I suggested elswhere about looking at evidence applies here
too. I don't have a reference handy but if you want to test your
ideas, why don't you seek out the observations that led to the
discovery of the Great Attractor and then run a simulation to
see if, you can produce that pattern by your model.
> There are some tiny lenses, and in some directions they
> congregate thickly enough to obscure the view beyond
> them, but most of the cosmic lensing is caused by the great
> preponderance of matter at the great attractor acting as a
> single giant lens. This causes all of the light in the universe
> to follow smoothly curving orbits, except in the vicinity of
> dense clusters of galaxies.
That is back to the goldfish bowl idea. We are used to thinking
of glass lenses that bend light more as it passes further from
the centre to produce a focus. The smoothly curving paths
created by a gravitational lens, that pass outside the group far
enough not to expose the detailed structure, bend less for paths
further from the centre. If the great attractor was responsible
for significant bending at 90 degrees to its position in the sky,
the majority of galaxies should appear in that hemisphere and we
should see large arcs at many degrees away from the GA centred
on it.
Going back to your approach, I would expect you to predict this
yourself, then look for evidence for it and if you don't find
it publish this as evidence against your theory. You seem to
avoid attempting to disprove your own theory, which is what a
professional would be doing.
George Dishman
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1028142912.20425....@news.demon.co.uk...
> > [Newsgroups trimmed]
> >
> > "Jeff Root" <je...@freemars.org> wrote in message
> > news:f0b30c00.02073...@posting.google.com...
> ..
> > > Martin apparently believes that scientists are as certain of
> > > their speculations as Martin is of his.
> >
> > It makes it easier to ignore them.
>
> Is that justified?
Possibly not.
>These conversations don't peter out
> because I ignore anything that others are saying. On the
> contrary, I try to deal with any valid points that anybody
> might raise, and that are directed at me. It is others who
> eventually discontinue the thread (and I don't mind that,
> I'm not saying that they should continue even if they
> don't want to, or if they can't afford the time).
I probably will too, mainly because you seem to be aware
of most of the information I could provide. You comments
on the linearity of the Hubble relation were an exception.
> Perhaps you mean that I ignore ideas which are
> different from my own, such as mainstream ideas,
> but my ideas are a specific response to flaws that
> I perceive in more mainstream theories. I don't see
> how I can be said to be ignoring them.
Perhaps 'ignoring' was not the best word but this is probably
a reasonable example of what I meant:
"Martin Gradwell" <mtgra...@btinternet.com> wrote in message
news:aidq2p$7rm$1...@newsg1.svr.pol.co.uk...
...
> At the top of the first page, "This map of the remnant heat
> *from the big bang* will provide answers to fundamental
> questions about the origin and fate of our universe."
> (My emphasis). There are similar sentiments expressed
> throughout the site. You can have your big bang with inflation,
> bb with quintessence, bb with a cosmological constant, bb
> with dark matter, or with dark energy, or you can have bb
> and chips, or bb with egg and chips, or bb and bb, or ...
>
> All of these "competing ideas" are different attempts to
> shore up one single flawed idea.
You don't seem to be looking at the evidence and treating
these as serious alternatives that could explain whatever
you see as 'flaws' but dismiss them out of hand. The
impression I get is not of a search for a better model but
a desire to defend your particular view. You should be as
critical of your own model as you are of others. The measure
of any theory is the thoroughness of the search for evidence
to falsify it.
George Dishman
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1028069376.9072.0...@news.demon.co.uk...
> ..
> > Try reading up on the variety of theories being tested by
> > the MAP project for example. There are dozens of competing
> > ideas and we are a long way from knowing which is correct.
>
> Looking at the MAP site, http://map.gsfc.nasa.gov/
> The big bang is a given, which is not even slightly questioned
> except once, on the Uni_101age page (see below).
> There is no mention of any known viable alternative.
>
> At the top of the first page, "This map of the remnant heat
> *from the big bang* will provide answers to fundamental
> questions about the origin and fate of our universe."
> (My emphasis). There are similar sentiments expressed
> throughout the site. You can have your big bang with inflation,
> bb with quintessence, bb with a cosmological constant, bb
> with dark matter, or with dark energy, or you can have bb
> and chips, or bb with egg and chips, or bb and bb, or ...
>
> All of these "competing ideas" are different attempts to
> shore up one single flawed idea.
What do you think the flaw is?
> on the http://map.gsfc.nasa.gov/m_uni/uni_101age.html
> page, it says
>
> "If the expansion age measured by MAP is smaller
> than the oldest globular clusters, then there is something
> fundamentally wrong about either the Big Bang theory
> or the theory of stellar evolution. Either way, astronomers
> will have to rethink many of their cherished ideas."
>
> Yes, but those astronomers won't even have any
> idea of where to start, until one of them comes up
> out of the blue with the startling idea that the universe
> might actually be collapsing, not expanding.
The scientific method suggests we should develop theories
empirically to predict nature. When a deviation occurs
from current thinking then that should drive the
development of the new ideas. If it requires a collapsing
model, so be it.
Note however that the current view says that the universe
is expanding in general, our own group of galaxies is
collapsing into the GA and IIRC we are already being sucked
in at ~450km/s. That is only a minor local disturbance in
the overall flow though.
George Dishman
I thought you were saying that the appearance of homogeneity
is due to light from the inhomogenous actual distribution
being scattered all over the sky by galactic lensing, in which
case the degree of blurring should also be homogenous.
> If you look at one of the diagrams on my website, e.g.
> http://www.btinternet.com/~mtgradwell/universe3-75.jpg
> the chaotic wedge-shaped regions to the left and
> the right represent regions which are effectively hidden
> from view behind clusters of galaxies that are dense
> enough to be opaque; but in other directions the view
> is clear enough.
In which case the vast majority of observation we make in
practice should be unaffected other than an overall
displacement of the objects away from the GA hence
conventional interpretations should be valid.
What I am saying is that for homogeneity to be an artefact
of extreme lensing, other measures such as blurring should
give similar indication of the secondary effects of the
lensing. I believe they do not do so.
Jeff Root
> Jeff Root <je...@freemars.org> wrote in message
> news:f0b30c00.02080...@posting.google.com...
> ..
>> Martin Gradwell replied (in small part) to Jeff Root:
>>
>>> Don't you think it's remarkable that photons "don't
>>> lose speed as they rise in a gravitational well", but
>>> they are just as incapable of escaping from a black
>>> hole as things that do lose speed?
>>
>> Yes. That's part of what makes black holes so fascinating.
>
> But, nobody on the outside of a black hole could ever
> observe the photons which fail to emerge from it. Nobody
> could see these photons failing to lose speed and yet also
> failing to escape.
be a useful clue in learning about the black hole. If the
black hole were *not* there, such photons *would* be seen.
It is a very limited source of information, but it does
provide *some* information.
> Their speed is fixed, not because there is any observation
> evidence that this is the case, but because that is how we
> have defined it to be.
are made constantly, under all kinds of conditions. When the
light is travelling through vacuum, it is always found to be
moving at the same speed relative to the observer. Special
relativity is merely an explanation of these counter-intuitive
observations. If you think the speed is different in some
conditions, I'd like to see observational evidence supporting
that view.
> Even if someone were somehow to cross the event horizon of a
> black hole (and they'd have to find it first, and devise some
> way of knowing that they had crossed the horizon when there is
> no actual detectable event that takes place at the so-called
> "event horizon"), There is no way they could pass on what they
> learn to anyone who remains outside. So, the interior of a
> black hole is the ultimate in untestable physics, except to
> observers who all happen to be inside one.
>
>>> Also, if I didn't believe in my "speculations", I can be
>>> fairly certain that nobody else would either. And I think
>>> it would be a great pity if nobody at all believed in them,
>>> because I find them fascinating.
>>
>> I speculate about a lot of things without believing in the
>> truth of the speculations. Sometimes I'm surprised to learn
>> that my speculations were correct. But believing in the truth
>> of a speculation which contradicts observations is a bad sign.
>
> Yes. I would never do that.
statements indicated that that is exactly what you are doing.
The triumph of hope over experience.
> instead of accepting the commonly accepted set.
having mostly been thought up by cosmologists 40 or 50 years
ago, and since then largely discarded (though not by all
cosmologists) as being inconsistent with further observations.
>> I recently heard (on BBC radio) a wonderful expression which
>> describes this: "The triumph of hope over experience."
>
> Did the programme have a wonderful expression
> describing those who believe in speculations which
> can never be contradicted by observations because
> they are, by definition, untestable?
imagination, rather than reality. Real theories have real
flaws, but here you have invented an imaginary flaw.
Robert Gilster
>
> "Robert Gilster" <grob...@qwest.net> wrote in message
> news:1X%29.124$Wj.8...@news.uswest.net...> > news:1028403712.22353....@news.demon.co.uk...
> > >
> > > "Robert Gilster" <grob...@qwest.net> wrote in message
> > > news:bNS29.24$Wj.2...@news.uswest.net...
> > > >
> > > > They have to actually exist at some point and they have to exist all
> the
> > > > time
> > >
> > > Of course, but particles don't have to behave exactly like billiard
> > > balls, and they don't have to behave exactly like waves.
> > >
> > > >- unless you believe the LSD theory that we are all one consciousness
> > > > experiencing ourselves subjectively. So at one point all those
waves
> > have
> > > > to be solids
> > >
> > > "Solid" is a description of the characteristics of a grouping of
> > > particles. Nothing requires that an individual item have the same
> > > properties that a group exhibits on average.
> >
> > That is very true but....
> >
> > How do you explain the "photographs" that various institutions around
the
> > world have taken of individual atoms? Are those fuzzy, but fairly
> distinct
> > images waves or particles?
>
> No, they are something between those two macroscopic near-equivalents.
>
> >Granted the images only show the interaction of
> > the "camera" with the electron cloud, but something did interact.
>
> Oh yes.
>
> > How would you explain how a neutron would be capable of knocking out a
> > particle from an atom and starting a chain reaction. That neutron you
> claim
> > is a wave AND a particle (or perhaps neither but something close to
them).
> > At what point does that neutron decide to exist as a particle to cause
the
> > collision -
>
> It never does 'exist as a particle' and it never exists as a wave.
> It always exists as something that is not quite either a wave or a
> particle, but it can still interact with other similar objects to
> transfer momentum under the right conditions, and it can still show
> interference and diffraction under other conditions.
>
> >remember that light waves don't interact like sound waves, fiber
> > optics have shown that to be true. Hmmm, again I show myself to be a
> > skeptic of Quantum Mechanics and the duality arguments.
>
> So was Einstein so I wouldn't worry about that. The essence of
> duality though is not that the object is sometimes a wave and
> sometimes a particle, instead it is always something that shares
> some common traits with both. Describing them as particles or
> waves is just a trick to help us think about the problem - it
> is about the shortcomings of our ability to visualise, not the
> nature of the objects.
> --
> George Dishman
> The arrow of time points in many directions.
>
a scientific law that describes what a particle of matter is. Its not a
solid, its not a wave, so what is it? The answer that I'm hearing is - "Its
neither, but it has properties of both."
That solution to the problem statement doesn't have sufficient evidence to
back it up outside of *indirect* observational evidence and evidence of that
nature is very difficult to *prove* beyond a reasonable doubt. I'm not
saying that your claims are or are not true, only that direct physical
evidence must be presented to the community at large before those claims
could be legitimized. Truly the solution that you have presented is more
philosophical than anything, and (having a degree in philosophy) have never
encountered a philosophical argument that was proven. Again I'm not saying
you're wrong, you're making this up, you're off the deep end, I'm just
stating how the arguments appear to me personally.
>
>
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:ai9qo6$r7b$1...@newsg4.svr.pol.co.uk...
> > Perhaps you mean that I ignore ideas which are
> > different from my own, such as mainstream ideas,
> > but my ideas are a specific response to flaws that
> > I perceive in more mainstream theories. I don't see
> > how I can be said to be ignoring them.
>
> Perhaps 'ignoring' was not the best word but this is probably
> a reasonable example of what I meant:
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:aidq2p$7rm$1...@newsg1.svr.pol.co.uk...
> ...
> > At the top of the first page, "This map of the remnant heat
> > *from the big bang* will provide answers to fundamental
> > questions about the origin and fate of our universe."
> > (My emphasis). There are similar sentiments expressed
> > throughout the site. You can have your big bang with inflation,
> > bb with quintessence, bb with a cosmological constant, bb
> > with dark matter, or with dark energy, or you can have bb
> > and chips, or bb with egg and chips, or bb and bb, or ...
> >
> > All of these "competing ideas" are different attempts to
> > shore up one single flawed idea.
>
> You don't seem to be looking at the evidence and treating
> these as serious alternatives that could explain whatever
> you see as 'flaws' but dismiss them out of hand.
Despite my facetiousness, I do see these "competing
ideas" as serious. I just don't see them as alternatives.
"Our equation doesn't work, so let's add a new factor
to it, and call it the cosmological constant". "No, let's
call it Dark Energy. That has a mysterious ring to it.
Cosmological constant sounds old-fashioned."
"Excuse me, chaps, but what do any of these terms
actually mean?" "They mean that our first equations
didn't work, so we had to add new factors to them.
If we didn't do that, we'd have to abandon our theory".
The alternatives aren't plain BB or BB with added
factors. They are BB with added (unexplained) factors,
or the abandonment of the BB theory because it doesn't
work. There is no guarantee that it will work with the
various embellishments either, but these are the best
that science has been able to come up with, even if they
don't actually explain anything.
> The
> impression I get is not of a search for a better model but
> a desire to defend your particular view.
Have you considered the possibility that my particular
view *is* a better model?
> You should be as
> critical of your own model as you are of others.
If my model is ever shown to be incompatible
with observations, I will certainly abandon it.
Now, if I didn't treat the other models in the
same way, if in the face of overwhelming evidence
of their incorrectness I hunted desperately for some
unexplained factor which would make everything
right again, then I would certainly not be being as
critical of my own model as I am of those others.
> The measure
> of any theory is the thoroughness of the search for evidence
> to falsify it.
I presume these newsgroups are widely read.
I have often described my cosmological ideas
in sci.astro and sci.physics.relativity. My arguments
can be dredged up using google, or some of them can
be found on my website, complete with illustrations
including one that is animated. I have often asked for
refutations of my ideas. I have also sought for
refutations, in libraries and using google and other
search engines. I have made specific predictions
which should be easily refuted if they are false.
To everybody: If you are reading this and you know
of a refutation of what I am saying, please feel free to
post it here. Just a URL linking to a relevant site will do.
If you know someone who you think can refute my ideas,
please feel free to pass on the text of this message
to them - but don't go overboard. I don't want to be
seen to be encouraging spam.
If you are reading this on something like google,
and the thread is no longer current, still feel free
to drop me a line. I will be happy to discuss these
ideas in any easily accessible public forum if I am
still able to do so, and if such forums still exist.
Briefly, for those who haven't been following, I say
that the universe is finite, closed, and inhomogeneous,
with a central attractor. Galaxies are created near the
fringes, and fall towards the centre where they are
ultimately destroyed. Light can orbit the universe
multiple times, creating the illusion of a larger universe
which is approximately homogeneous at large scales.
Eventually the higher energy photons condense into
new matter, which forms new galaxies, and the cycle
can in principle repeat indefinitely. The real accelerating
infall of each galaxy creates the illusion of an accelerating
expansion.
I am not aware of any falsification of this idea,
or even of any discussion of it other than that
which I have instigated. I am aware of numerous
assertions which contradict the various elements
of my theory - assertions that the universe is
actually infinite, open, expanding, homogeneous,
etc., but not of anything that would justify these
assertions. I have read the FAQ, and many other
sites and books.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
Robert J. Kolker
Robert Gilster wrote:
> If what you say is true, then physics will never be able to prove or create
> a scientific law that describes what a particle of matter is. Its not a
> solid, its not a wave, so what is it? The answer that I'm hearing is - "Its
> neither, but it has properties of both."
We are so constituted that only way we -understand- our experience is by
metaphor and analogy. Once we gather perceptions we make sense out of
them by inventing good stories about them.
Bob Kolker
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:ai9se9$h5i$1...@newsg1.svr.pol.co.uk...
> >
> > George Dishman <geo...@briar.demon.co.uk> wrote in message
> > news:1028144333.21289....@news.demon.co.uk...
> > > The effect is like looking at a pin-point source through a
> > > goldfish bowl while in your concept it would be like seeing
> > > a floodlight through frosted glass.
> >
> > I'm not saying that cosmic-scale lensing is the same as a
> > lot of tiny lenses all operating individually, like frosted glass.
>
> No, I am.
Then it is your theory that is flawed, not mine. :-)
> Look at the Abell 2218 picture you posted and you will
> see many small arcs within the group caused by individual galaxies.
> Take that to an extreme and you will get a frosted glass effect
> with large numbers of arcs filling the picture.
Only if the extreme consists of the entire sky being filled in
every direction with similar small lenses. However if there is
a predominance of matter in the direction of the great attractor,
both because of the presence of dense clusters of large galaxies
there and because of the presence of an unseen attractor which
is considerably more massive than all those galaxies put together,
then this matter can act as a single giant lens. This lens affects
the path taken by light reaching us from every part of the sky,
including parts where there is no local disruption of the field of
view by small gravitational lenses.
> Now you also wrote:
>
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:ai9rpq$bpu$1...@newsg2.svr.pol.co.uk...
> >
> > George Dishman <geo...@briar.demon.co.uk> wrote in message
> > news:1028143822.20954....@news.demon.co.uk...
> > ...
> > > > > > E x A y
> > > > > >
> > > > > > E is the Earth, A is the Great Attractor, galaxies at
> > > > > > x have higher red-shift than the Hubble flow while those
> > > > > > at y have less than expected
> > ...
> > > > Light from x which initially moves to the right will pass very
> > > > close to A, where there is a very dense collection of large
> > > > galaxies, making that region of space almost opaque. It will
> > > > then be slingshotted around the singularity located at the
> > > > attractor, and head towards us, again running the gauntlet
> > > > of that dense collection of galaxies. If it reaches us without
> > > > being intercepted, its direction will have been slightly randomised,
> > > > so that it will not form a clear image of a blueshifted galaxy.
>
> If the light from x to A reaches E, it has been turned through
> 180 degrees by the singularity so the distrion is extreme, and
> then it runs "the gauntlet of that dense collection of galaxies".
> That gives me the feeling that we would see the returning light
> through the frosted effect of the group.
Yes. There are parts of the sky where the galaxies
cluster together so thickly that they effectively form
an opaque region. Your mistake is still to believe in the
assertions of universal homogeneity. If the universe
really was homogeneous and isotropic then we would
see this frosting effect in every part of the sky. We do not
(except at very high z, beyond the furthest quasar images).
>
> What I suggested elswhere about looking at evidence applies here
> too. I don't have a reference handy but if you want to test your
> ideas, why don't you seek out the observations that led to the
> discovery of the Great Attractor and then run a simulation to
> see if, you can produce that pattern by your model.
Several of the diagrams on my website, including the animated
diagram, were not hand drawn. They were produced by a
simulation program that I wrote to test my model. It wasn't
a very sophisticated program, but my impression is that the
output from it is reasonably similar to what is actually observed.
Certainly it gives a closer fit to reality than an assumption of
local randomness and global homogeneity would.
>
> > There are some tiny lenses, and in some directions they
> > congregate thickly enough to obscure the view beyond
> > them, but most of the cosmic lensing is caused by the great
> > preponderance of matter at the great attractor acting as a
> > single giant lens. This causes all of the light in the universe
> > to follow smoothly curving orbits, except in the vicinity of
> > dense clusters of galaxies.
>
> That is back to the goldfish bowl idea. We are used to thinking
> of glass lenses that bend light more as it passes further from
> the centre to produce a focus. The smoothly curving paths
> created by a gravitational lens, that pass outside the group far
> enough not to expose the detailed structure, bend less for paths
> further from the centre.
This is true except where the light has climbed so far out
of the attractor's gravitational well that it has lost much of
its energy. In any elliptical path there are *two* regions
where there is greater than average bending of the path.
See http://www.btinternet.com/~mtgradwell/univ-ray.jpg
for a depiction of numerous sections of elliptical paths,
all converging on one location under the influence of a
central attractor.
> If the great attractor was responsible
> for significant bending at 90 degrees to its position in the sky,
> the majority of galaxies should appear in that hemisphere and we
> should see large arcs at many degrees away from the GA centred
> on it.
We do see large arcs at many degrees from the GA and
centred on it. The Perseus-Pisces supercluster is one such arc.
>
> Going back to your approach, I would expect you to predict this
> yourself, then look for evidence for it and if you don't find
> it publish this as evidence against your theory.
But I *do* find it.
> You seem to
> avoid attempting to disprove your own theory, which is what a
> professional would be doing.
Your only evidence for this assertion is the fact that I have
never found a disproof of my theory. You don't know how
hard I have searched for one, or for how many years.
Martin Gradwell
..
> I thought you were saying that the appearance of homogeneity
> is due to light from the inhomogenous actual distribution
> being scattered all over the sky by galactic lensing, in which
> case the degree of blurring should also be homogenous.
The appearance of homogeneity is approximate, not absolute,
and it only applies at large scales. In our immediate vicinity
we do not see a homogeneous collection of galaxies. Instead
in one direction we see the great attractor and several dense
compact superclusters containing many large elliptical radio
galaxies, consistent with them being older than our own cluster.
In the other direction we see very little in the way of dense
clusters in the immediate vicinity, but we do see some great
curving ribbons of galaxies which subtend enormous angles.
>
> > If you look at one of the diagrams on my website, e.g.
> > http://www.btinternet.com/~mtgradwell/universe3-75.jpg
> > the chaotic wedge-shaped regions to the left and
> > the right represent regions which are effectively hidden
> > from view behind clusters of galaxies that are dense
> > enough to be opaque; but in other directions the view
> > is clear enough.
>
> In which case the vast majority of observation we make in
> practice should be unaffected other than an overall
> displacement of the objects away from the GA hence
> conventional interpretations should be valid.
If the overall displacement is large enough it can wrap
around. Some of the galaxies which appear to be near
the great attractor and to the left of it will actually be to
the right of it. Distant images which appear to be in the
opposite direction to the attractor will actually originate
from the vicinity of the attractor, or will be images of
the attractor. Does the conventional interpretation say
this?
>
> What I am saying is that for homogeneity to be an artefact
> of extreme lensing, other measures such as blurring should
> give similar indication of the secondary effects of the
> lensing.
Yes. But only for light that has had to pass very close
to several small lenses. That is, only in certain regions of
the sky.
> I believe they do not do so.
We disagree on this point.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
George Dishman
>
> "George Dishman" <geo...@briar.demon.co.uk> wrote in message
> news:1028454681.5436.0...@news.demon.co.uk...
> >
> > It always exists as something that is not quite either a wave or a
> > particle, but it can still interact with other similar objects to
> > transfer momentum under the right conditions, and it can still show
> > interference and diffraction under other conditions.
> > ... The essence of
> > duality though is not that the object is sometimes a wave and
> > sometimes a particle, instead it is always something that shares
> > some common traits with both. Describing them as particles or
> > waves is just a trick to help us think about the problem - it
> > is about the shortcomings of our ability to visualise, not the
> > nature of the objects.
> >
create
> a scientific law that describes what a particle of matter is. Its not a
> solid, its not a wave, so what is it? The answer that I'm hearing is -
"Its
> neither, but it has properties of both."
Right, but that doesn't stop us noting laws that apply to such
objects. They are the laws of quantum mechanics.
> That solution to the problem statement doesn't have sufficient evidence to
> back it up outside of *indirect* observational evidence and evidence of
that
> nature is very difficult to *prove* beyond a reasonable doubt. I'm not
> saying that your claims are or are not true, only that direct physical
> evidence must be presented to the community at large before those claims
> could be legitimized.
The laws of QM are quite different from either Newtonian mechanics
(particles) or classical optics (waves). Is that an adequate proof
that whatever those laws describe, they are not exactly the same as
a classical particle and they are not exactly the same as a wave?
> Truly the solution that you have presented is more
> philosophical than anything, and (having a degree in philosophy) have
never
> encountered a philosophical argument that was proven. Again I'm not
saying
> you're wrong, you're making this up, you're off the deep end, I'm just
> stating how the arguments appear to me personally.
I have no knowledge of philosophy at all but please don't make
the mistake of thinking I am trying to push a new idea, I simply
understand the word 'duality' to imply characteristics of both
and presenting a way of thinking that seems to follow from that.
Let me turn it around and ask can you identify any macroscopic
class of object that obeys the same rules as QM? For example is
there something I could hold in my hand that would appear fuzzy
due to the Uncertainty Principle (rather than Marketing)?
George Dishman
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1028383995.11938....@news.demon.co.uk...
> ..
> > I thought you were saying that the appearance of homogeneity
> > is due to light from the inhomogenous actual distribution
> > being scattered all over the sky by galactic lensing, in which
> > case the degree of blurring should also be homogenous.
>
> The appearance of homogeneity is approximate, not absolute,
> and it only applies at large scales. In our immediate vicinity
> we do not see a homogeneous collection of galaxies. Instead
> in one direction we see the great attractor and several dense
> compact superclusters containing many large elliptical radio
> galaxies, consistent with them being older than our own cluster.
> In the other direction we see very little in the way of dense
> clusters in the immediate vicinity, but we do see some great
> curving ribbons of galaxies which subtend enormous angles.
Other than the limitations of the dust in the Milky way,
I was under the impression we see such structures in all
directions. I would have to look at the distributions to
answer you on that.
> > > If you look at one of the diagrams on my website, e.g.
> > > http://www.btinternet.com/~mtgradwell/universe3-75.jpg
> > > the chaotic wedge-shaped regions to the left and
> > > the right represent regions which are effectively hidden
> > > from view behind clusters of galaxies that are dense
> > > enough to be opaque; but in other directions the view
> > > is clear enough.
> >
> > In which case the vast majority of observation we make in
> > practice should be unaffected other than an overall
> > displacement of the objects away from the GA hence
> > conventional interpretations should be valid.
>
> If the overall displacement is large enough it can wrap
> around. Some of the galaxies which appear to be near
> the great attractor and to the left of it will actually be to
> the right of it. Distant images which appear to be in the
> opposite direction to the attractor will actually originate
> from the vicinity of the attractor, or will be images of
> the attractor. Does the conventional interpretation say
> this?
My impression is that it could do that only with a non-trivial
topology but that is based only on what I have seen posted by
others. I have no competence in GR.
> > What I am saying is that for homogeneity to be an artefact
> > of extreme lensing, other measures such as blurring should
> > give similar indication of the secondary effects of the
> > lensing.
>
> Yes. But only for light that has had to pass very close
> to several small lenses. That is, only in certain regions of
> the sky.
>
> > I believe they do not do so.
>
> We disagree on this point.
Fair enough.
George Dishman
I see them as evidence that there is a willingness to
consider all the alternatives within the limits of
observation.
> "Our equation doesn't work, so let's add a new factor
> to it, and call it the cosmological constant". "No, let's
> call it Dark Energy. That has a mysterious ring to it.
> Cosmological constant sounds old-fashioned."
> "Excuse me, chaps, but what do any of these terms
> actually mean?" "They mean that our first equations
> didn't work, so we had to add new factors to them.
> If we didn't do that, we'd have to abandon our theory".
The Cosmological Constant was in GR from the very first.
In fact Einstein regretted putting it there, but it has
been there for nearly a century nonetheless. All that
has happened is that we now have the technology to make
a first stab at measuring it, and the result is not what
was expected. That's progress. It doesn't mean we know
what causes it yet, or even what the value is to any
great accuracy.
> The alternatives aren't plain BB or BB with added
> factors. They are BB with added (unexplained) factors,
> or the abandonment of the BB theory because it doesn't
> work. There is no guarantee that it will work with the
> various embellishments either, but these are the best
> that science has been able to come up with, even if they
> don't actually explain anything.
The only 'embellishment' I know of is Guth's inflation.
I agree, it is only the best we have so far, but that
is true of all theories and always will be.
> > The
> > impression I get is not of a search for a better model but
> > a desire to defend your particular view.
>
> Have you considered the possibility that my particular
> view *is* a better model?
The paper you quoted shows there are people considering
this sort of idea. I am not capable of working at that
level. However, a few things you say conflict with some
basic rules and cause me to think you haven't done some
basic groundwork. The most obvious is your repeated
mention of closed elliptical paths for photons.
> > You should be as
> > critical of your own model as you are of others.
>
> If my model is ever shown to be incompatible
> with observations, I will certainly abandon it.
Then you should show that the mass distribution that
you propose produces elliptical orbits. That is the
sort of test I would expect you to be doing.
> Now, if I didn't treat the other models in the
> same way, if in the face of overwhelming evidence
> of their incorrectness I hunted desperately for some
> unexplained factor which would make everything
> right again, then I would certainly not be being as
> critical of my own model as I am of those others.
Where is this "overwhelming evidence"? All you have
talked about so far is the non-zero value for the
Cosmological Constant which has been a parameter
waiting to be measured since GR was first published.
Ok here is a first stab. Your description is symmetrical
about the central mass. This diagram shows five galaxies
(or large structures of galaxies if you like) falling
toward the central mass X.
A
D B E X
C
We are at B. D and E will appear to move away from us
hence would be red-shifted but A and C will appear to
be blue-shifted. However, we observe uniform redshift.
Now I am sure you will say this is explained by the
bending of the light, but I do not see how that can
happen for all the observers in a circle at the same
radius from X as B due to the symmetry.
Jeff Root
description of the properties of subatomic matter:
> If what you say is true, then physics will never be able to
> prove or create a scientific law that describes what a particle
> of matter is.
Absolutely no connection between what George said and what you
say it implies.
> Its not a solid, its not a wave, so what is it?
describes it and also accurately describes something that is
big enough for you to see and feel isn't going to make it any
more real. Doing that just makes it easier for *you* to talk
about it. Accurately describing the properties of a thing is
even better than putting a name like "solid" or "wave" on it,
and that is exactly what physics does for subatomic matter:
accurately describe it such that accurate predictions can be
made about its behavior.
> The answer that I'm hearing is - "Its neither, but it has
> properties of both."
"a solid", but I suspect that individual protons, electrons,
neutrons, mesons, and quarks do not fit your definition.
I think we *probably* both have pretty much the same idea of
what "a wave" is, and it seems obvious that matter is not
composed of waves, but experiments (some of them quite easy
to do) show that matter definitely has the properties of
waves, seen in the matter's behavior.
A circle is not a solid and not a wave, yet we both know
what it is.
A message is not a solid and not a wave, yet we both know
what it is.
A smile is not a solid and not a wave, yet we both know
what it is.
> That solution to the problem statement doesn't have sufficient
> evidence to back it up outside of *indirect* observational
> evidence and evidence of that nature is very difficult to
> *prove* beyond a reasonable doubt.
your naked eye that the lump is indeed, a lump of proton, before
you will believe that protons exist? Seeing tracks of protons
on film made by their interaction with other invisible particles
isn't good enough?
> I'm not saying that your claims are or are not true, only that
> direct physical evidence must be presented to the community at
> large before those claims could be legitimized.
evidence produced over the last 100 years and still thinks that
claims that protons and electrons exist are not "legitimized"
is severely mentally handicapped. I do mean *severely*.
> Truly the solution that you have presented is more
> philosophical than anything, and (having a degree in philosophy)
> have never encountered a philosophical argument that was proven.
looks like a philosophical statement. It does not look like
a philosophical statement to me at all. It is a description
of what is observed.
> Again I'm not saying you're wrong, you're making this up,
> you're off the deep end, I'm just stating how the arguments
> appear to me personally.
you know almost nothing about how science works or what it has
learned in the last 100 years, or you have astonishingly poor
judgement, or you are quite sick, or some combination.
Robert Gilster
systematically glossed over the point of what I was trying to say. Perhaps
my wording wasn't so clear, but George doesn't seem to have a problem with
it.
Answer me this and I'll see if I can rise to the tall pedestal you stand
atop.
What is a neutron - is it an object (that is a thing with structure, mass,
rigidity) or is it a wave (energy with no rigidity or mass or structure) or
is it both. Based on my conversations with George it is both. The next
question is this: if a neutron represents what all subatomic particles are
like physically, then at what point does that particle decide to become an
object to interact with other particles (who in turn decide to act like
objects) and at what point does that particle decide to act like a wave?
> .
Robert Gilster
No I can't, and you make a good argument. Pretty big sticking point. Like
I said, sounds like the beginnings of a philosphical argument. But I won't
go there, sounds like the guys in sci.physics are tired of having their
theories questioned by outsiders, crazies, and uneducated. Shame I got that
reply from Jeff Root, I was beginning to get interested in the research.
Jeff Root
>> Again I'm not saying you're wrong, you're making this up,
>> you're off the deep end, I'm just stating how the arguments
>> appear to me personally.
>
> you know almost nothing about how science works or what it has
> learned in the last 100 years, or you have astonishingly poor
> judgement, or you are quite sick, or some combination.
your message for the fourth time (really!) when I discovered
that I had misread your sentence with multiple elliptical
clauses. You were saying the exact opposite of what I thought
you were saying, of course! Since you don't think George was
making it up, none of the above applies -- of course!
My apologies. My mistake!
Jeff Root
> Again I'm not saying you're wrong, you're making this up,
> you're off the deep end, I'm just stating how the arguments
> appear to me personally.
Reading it a sixth time, I now wonder how I could have read
it wrong the first three times. Either syntax works, but the
one you meant works better than the one I thought you meant.
Again, my apologies.
Edward Green
> Bennett Standeven <be...@pop.networkusa.net> wrote in message
> news:24c3076b.02072...@posting.google.com...
> > use...@mantra.com (Dr. Jai Maharaj) wrote in message
> news:<Jyotish-17...@news.mantra.com>...
> > > Is the Universe older than expected?
> ..
> > > One possible explanation is that something is wrong with
> > > the way astronomers measure the age of objects in the
> > > Universe. The almost-holy red shift-distance-age
> > > conversion would therefore be wrong. Fred Jansen, ESA's
> > > project scientist for XMM-Newton, explains that this
> > > would mean rewriting the textbooks. "If you study the
> > evolution of the Universe, one of the basic rules is that
> > > we can tie redshift to age. One distinct possibility to
> > > explain these observations is that, at the redshift we
> > > are looking at, the Universe is older than we think."
> > >
> >
> > How would that help? To explain the results, the Universe would have
> > to have been older 13.5 billion years ago than it is now. That doesn't
> > seem very likely...
Exactly. The "universe may be older than we think" precis is about
the most misleading thing I have ever read!
If I follow the logic of the thing, adding a little dim knowledge of
my own, the source of all or almost all iron in the universe is
exploding stars. Furthermore, iron is only created late in a star's
life; the iron production stage does not last long, and is rapidly (in
cosmological time) followed by an explosion injecting the iron into
space, where it may eventually be recycled into other stars and
planets.
In other words the fraction of iron in a gravitationally condensed
system is a frozen snapshot of conditions at the time of its
formation, and does not alter until the system is about to be
dispersed. Assuming we use iron as a cosmic clock, this implies the
object we are looking at was formed _later_ than 13.5 billion years
ago ... is _newer_. In fact, it implies it is newer than the solar
system.
Now parse the quote from Fred Jansen carefully:
"One distinct possibility to explain these observations is that, at
the redshift we are looking at, the Universe is older than we think".
What an ass-backwards way of expressing this idea! It's like saying
"We think these papers were from 1950. But when these papers were
printed, the century was older than we thought". This doesn't mean
that the papers were printed in 1950, and the year 1900 was somehow
back-dated. This means the papers were printed later!
Strunk and White, demi-gods of style, come and smite this Jensen!
Make him write out 1000 times "...possibility is ... at the redshift
we are looking at, we are looking closer to the present than we
thought".
Well, he probably doesn't quite want to say this either.
In fact the implied dichotomy "universe older than we think", "iron
factories" is plain nonsense. We find at a minimum that both clocks
cannot always keep good time. A simplest hypothesis might be that we
see this quasar precisely at an explosive production of iron. At any
epoch of the universe the iron content of that small fraction of
bodies actively _producing_ iron will be higher than the general
background.
The esteemed OP seems to have a genius for quoting articles in support
of the thesis "science writers are bozos". Misled by Jansen's
unfortunate phrasing and not bothering to think, the writer dutifully
reported that the universe may be "older than we think". Just as
"breaking the 2nd law of thermodynamics" sounds more exciting than
"observing some expected statistical fluctuations", the phrase "the
universe may be older than we think", is much more exciting than "this
picture may have been taken more recently than we think"; so exciting
that we forget the rest of the phrase: "...older than we think ...
when the picture was taken".
In other words, the picture was taken more recently than we thought.
> How about if it was exactly the same age, 13.5 billion years
> ago, as it is today?
>
> If you read carefully, the claim is that the quasar, 13.5 billion
> years ago, might have been older than *our solar system* is
> today (because it contains a higher proportion of iron than
> our sun does). Older than our solar system, *not* older than
> our universe.
Think again. The claim is really that at whatever epoch we are
observing the quasar the universe was _older_ than it was at the
formation of our solar system. Translation: the quasar was formed
_more recently_ (at least according to the iron clock) than our solar
system -- and we are not looking 13.5 billion years in the past.
The entire content of this anomoly is that there is a conflict between
the redshift clock and the iron clock. At least one of them is wrong
here.
Keeping the 13.5 billion year in the past estimate _and_ the iron
clock doesn't work, because it implies that our solar system has
anomolously _little_ iron; after all, it was formed 8.5 billion years
later than the quasar.
> Suppose, for example, that the quasar was formed 28.5 billion
> years ago. It would then have been 15 billion years old at the
> time when it emitted the light that we see today. That's three
> times the current age of our solar system. We might then expect
> it to have three times the iron content of our sun, if iron content
> was linearly related to age.
I don't think that's the logic of the iron clock. It's not how old
the object is, it's how old the universe was at the time the object
condensed. The iron concentration of that epoch is frozen in. It's
like dating glacial cores by analyzing trace elements.
MOA Observer
I have just come across your model and there is something which doesn't
add up for me.
Just to be clear I am talking about the light which has travelled the
most direct path too us from distant objects at about the same radius
from the attractor. In your picture Diagram of collapse I am talking
about F: Shorter light paths. You explain the lack of blue-shifted
distant objects by the zigzag path of the light due to the bending
(lensing) by massive bodies to my mind this would need a much larger
density of lenses than we observe. There must be some objects at around
2Mpc+ for which the light is not bent (lensed) because there is no
massive object between us and the source. What you are saying is that
the light from every object with a distance larger than about 2Mpc
(which all show red shift I think) has had the light follow a zigzag
path due to lensing but we don't see these lenses.
Assuming that there is enough massive objects to cause this zigzag path
the effect would be random so there would be a certain percent of
distant objects which show blue-shift. I'll explain how we should get
some blue shifted objects. We have a bunch of objects at 10 Mpc from us
and at the around the same radius from the attractor as us. These
objects are travelling toward us. A ray of light from one of these
objects is emitted directly toward us and is then bent several times
following a zigzag path you described then finally reaches earth will
still show blue-shift. I used your diagram of collapse to estimate that
there is a 10 % chance of the distant object B showing blue-shift to an
observer at A. Any ray emitted from source B at an angle of less than
20 degrees to us(A) would be blue shifted. (My spherical geometry is a
bit rusty so I am using estimates). Because the zigzag process is random
there would be a number of distant objects showing blue-shift can you
tell me of any?
Paul
Jeff Root
> You need to read the words on the virtual page more closely big guy.
shock. I scrambled to write a new message and get back online.
Unfortunately it was more than an hour after posting the first
message.
I think that you are probably the first person who has ever
called me "big guy". Relative to a baby or a puppy or an ant,
though, it's accurate. :-) No, I'm not a midget. :-)
> You systematically glossed over the point of what I was trying
> to say. Perhaps my wording wasn't so clear, but George doesn't
> seem to have a problem with it.
could have addressed differently? I responded to every last
sentence in that message, though I regret responding to the
*last* sentence in that message....
> Answer me this and I'll see if I can rise to the tall pedestal
> you stand atop.
your questions.
> What is a neutron - is it an object (that is a thing with structure,
> mass, rigidity) or is it a wave (energy with no rigidity or mass or
> structure) or is it both. Based on my conversations with George it
> is both.
I'll avoid the word "object" because that word seems pretty
clearly to apply to big things you can see, like pedestals and
holes (can you see holes?), but not necessarily to little things
you can't see.
A neutron is something that has mass, for sure. I have read
that neutrons have structure, but not the details about how
that is known. I can only cite one argument for the existence
of neutron structure: Neutrons are electrically neutral -- they
have no overall electric charge. But they act like magnets, so
there must be electric charges in motion inside them.
I'm not sufficiently familiar with mechanical engineering to
be sure what the term "rigidity" means. In general I think it
means resistence to bending. Maybe resistence to compression
is what you have in mind. Either way I'm afraid I'll just have
to say that I don't know enough about the behavior of neutrons
when forces are applied to them to say anything definite.
Obviously this is critical in describing neutron stars.
Neutrons certainly do bump into protons and other neutrons, so
they act like particles in that sense.
I have no reason to think that neutron are waves, but they
definitely have properties of waves. Interference patterns
can be made with neutrons as with light and electrons.
Neutrons of course have energy. Mass is a form of energy.
They also have spin angular momentum and a couple of other
properties. When not coupled with other nucleons, neutrons
are unstable, spontaneously breaking down into a proton, an
electron, and an electron antineutrino, with a half-life of
about 15 minutes.
I know that doesn't really answer your question, but I've
described neutrons about as well as I can. Others can and
have done better.
> The next question is this: if a neutron represents what all
> subatomic particles are like physically, then at what point does
> that particle decide to become an object to interact with other
> particles (who in turn decide to act like objects) and at what
> point does that particle decide to act like a wave?
neutrons you are looking at. If you are looking at collisions
or measuring mass, you see behavior similar to the behavior of
particles. If you are looking at interference patterns, you
see behavior similar to the behavior of waves.
MOA Observer
I think my estimate was a bit large the angle is probably much less making
the chanch of the object being blue shifted lower but I think it will still
be high enough to be observed.
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:aidq2p$7rm$1...@newsg1.svr.pol.co.uk...
> >
> > George Dishman <geo...@briar.demon.co.uk> wrote in message
> > news:1028069376.9072.0...@news.demon.co.uk...
> > ..
> > > Try reading up on the variety of theories being tested by
> > > the MAP project for example. There are dozens of competing
> > > ideas and we are a long way from knowing which is correct.
> >
> > Looking at the MAP site, http://map.gsfc.nasa.gov/
> > All of these "competing ideas" are different attempts to
> > shore up one single flawed idea.
>
> What do you think the flaw is?
The Big Bang is a time-reversed variation on the
19th-century theme that "if present trends continue
then Londoners will all soon be buried under a vast
pile of horse droppings". It takes a perceived trend
and extrapolates it to an illogical conclusion.
Of course this can only make even a dubious kind
of sense if the "expansion" is either decelerating or
proceeding at a fixed rate, and if the universe is
homogeneous. So, it was confidently asserted that
the universe was indeed homogeneous, and that it
was expanding at a decelerating rate.
Numerous observations have contradicted the basic
assumptions, but the theory is too deeply entrenched
to be greatly affected by facts.
Margaret Geller, on the large-scale structure known
as the"Huchra-Geller wedge":
"I didn't expect to see it, because the party line was
that it wasn't there."
Ditto for the Great Attractor, etcetera. The party
line was that the universe was homogeneous. This
assumption acted as a great brake on discovery.
How much sooner could the acceleration have
been discovered, if everybody hadn't "known",
for certain, that the expansion was decelerating?
And now, people want to patch up the theory,
by adding a term or two into the equations. They
say that the inhomogeneities don't count because
they're only a few hundred million light years across,
and that's "small". Millions of galaxies is "small"!?
The added terms allow the equations to describe
an accelerated expansion, but that is all they do.
They don't predict anything new, over and above
the phenomenon that prompted their introduction,
and they don't explain anything. They don't tie in
with anything else.
What about tomorrow's Earth-shattering discoveries?
Standard theory doesn't predict them, of course,
otherwise they wouldn't be Earth-shattering. But will
it really be the case that "astronomers will have to
rethink many of their cherished ideas"? No, unless
"rethink" means "add another small term into the
equation".
It doesn't matter what is discovered tomorrow,
there will always be a small patch that can be applied
to the standard theory to immunize it against the new
observations. There can always be a Big Bang, whether
it actually happened or not.
Each new discovery will come as a shock. Each will be
unpredicted. Each will be delayed by several decades,
because nobody will be looking for it. But, we will always
be able to retrofit the theory to accomodate the new
observations, so we can always be happy that we have
"explained" everything that we can currently see.
>
> > on the http://map.gsfc.nasa.gov/m_uni/uni_101age.html
> > page, it says
> >
> > "If the expansion age measured by MAP is smaller
> > than the oldest globular clusters, then there is something
> > fundamentally wrong about either the Big Bang theory
> > or the theory of stellar evolution. Either way, astronomers
> > will have to rethink many of their cherished ideas."
> >
> > Yes, but those astronomers won't even have any
> > idea of where to start, until one of them comes up
> > out of the blue with the startling idea that the universe
> > might actually be collapsing, not expanding.
>
> The scientific method suggests we should develop theories
> empirically to predict nature. When a deviation occurs
> from current thinking then that should drive the
> development of the new ideas.
And since the deviation will generally be small, the
assumption will be that the new theory should be a
small variation on the old one. Even when that old
theory has already been rocked by numerous small
deviations from expectation, each of which led to a
small variation in the theory. Well, I suppose it's nice,
in some ways, to be perpetually astonished by each
new observation.
> If it requires a collapsing
> model, so be it.
Some models make more sense than others, but no
model is ever required. There are always alternatives
that can be imagined. Some of them might be far-
fetched, but that doesn't matter if they have evolved
from an older model that has found widespread
acceptance.
It would be nice if someone who sees that a
collapsing model makes a great deal of sense
could put this message across and be noticed
by the establishment. Can it really happen,
though?
>
> Note however that the current view says that the universe
> is expanding in general, our own group of galaxies is
> collapsing into the GA and IIRC we are already being sucked
> in at ~450km/s. That is only a minor local disturbance in
> the overall flow though.
Our own local group of galaxies is collapsing into itself.
It is likely that it will eventually be a single elliptical radio
galaxy, like many of the galaxies that are nearer to the
attractor. It recapitulates their history.
It is being drawn towards the attractor, along with
a very large number of galaxies over a region that is
hundreds of millions of light years across. That is not
a minor local disturbance, unless you apply very broad
definitions of "minor" and "local". But we are supposed
to believe that we are not being sucked in, because the
Hubble expansion trumps the pull of the attractor.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, ntgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
Martin Gradwell
Jeff Root <je...@freemars.org> wrote in message
news:f0b30c00.02080...@posting.google.com...
> Martin Gradwell again replied to Jeff Root:
> > But, nobody on the outside of a black hole could ever
> > observe the photons which fail to emerge from it. Nobody
> > could see these photons failing to lose speed and yet also
> > failing to escape.
>
> True. However, the fact that they cannot be seen can itself
> be a useful clue in learning about the black hole. If the
> black hole were *not* there, such photons *would* be seen.
And the fact that we don't see the invisible lions under
the desk proves that they too are invisible? :-)
If the black hole were *not* there, what would be
the source of the photons that *would* be seen?
> It is a very limited source of information, but it does
> provide *some* information.
>
> > Their speed is fixed, not because there is any observation
> > evidence that this is the case, but because that is how we
> > have defined it to be.
>
> I don't see this at all. Observations of the speed of light
> are made constantly, under all kinds of conditions. When the
> light is travelling through vacuum, it is always found to be
> moving at the same speed relative to the observer.
In 1983 the value of the speed of light in a vacuum was
fixed at exactly 299,792,458 metres per second, and this
value was adopted as a new standard. The metre was
redefined as the length of the path traveled by light in a
vacuum in 1/299,792,458 of a second. So, it is utterly
impossible for light travelling through a vacuum to do so
at any other speed, by definition. If you think that you
have detected light travelling through a vacuum at any
other speed, you must be mistaken - your metre stick
isn't exactly a metre wrong, or maybe your clocks don't
keep good time.
Pre-1983, attempts to measure of the speed of light
were made, but now we would have to say that these
experiments used light to measure variations in the length
of a reference-object or in the frequency of some periodic
event used as a clock.
> Special
> relativity is merely an explanation of these counter-intuitive
> observations. If you think the speed is different in some
> conditions, I'd like to see observational evidence supporting
> that view.
Special relativity says nothing about situations in which
gravitation is a significant factor.
There have been attempts to measure the speed of
light over large distances e.g. by observing the eclipses
of Jupiter's moons. In fact, historically, these were the
first measurements. But, they only give an approximate
figure, and apparent variations can always be explained
as variations in the distance involved, while the speed
of the light stays fixed. This results in a non-Euclidean
geometry, but nobody seems to mind that nowadays.
Measurement of the speed of light over a fixed,
measured distance has only ever been done at
or very near the earth's surface. Nobody has even
done it on the moon, let alone on another planet, or
in the vicinity of the sun, or at the core of the galaxy,
or in the depths of intergalactic space. Now, of
course, they don't need to.
..
> > That is why I had to come up with my own set of speculations,
> > instead of accepting the commonly accepted set.
>
> Except that "your own" speculations weren't original with you,
> having mostly been thought up by cosmologists 40 or 50 years
> ago, and since then largely discarded (though not by all
> cosmologists) as being inconsistent with further observations.
Can you provide a published reference to a continuously
collapsing inhomogeneous cosmology that was thought up
40 or 50 years ago? I seriously doubt it.
In any case, such a cosmology was bound to be
dismissed 40 or 50 years ago, because all the "evidence"
would have been against it. The universe was homogeneous.
It was expanding uniformly, but the expansion was
decelerating. Everybody "knew" that. I faced the same
objections about 20 years ago, and they did seem to pose
a serious problem for me then. I still face these objections,
from people who aren't aware of the latest developments
or who think that structures hundreds of millions of light
years across are insignificantly small.
..
Martin Gradwell
>
> "George Dishman" <geo...@briar.demon.co.uk> wrote in message
> news:1028454681.5436.0...@news.demon.co.uk...
> > So was Einstein so I wouldn't worry about that. The essence of
> > duality though is not that the object is sometimes a wave and
> > sometimes a particle, instead it is always something that shares
> > some common traits with both. Describing them as particles or
> > waves is just a trick to help us think about the problem - it
> > is about the shortcomings of our ability to visualise, not the
> > nature of the objects.
> > --
> > George Dishman
> > The arrow of time points in many directions.
> >
> If what you say is true, then physics will never be able to prove or
create
> a scientific law that describes what a particle of matter is. Its not a
> solid, its not a wave, so what is it? The answer that I'm hearing is -
"Its
> neither, but it has properties of both."
Perhaps you'll like my explanation (but I doubt it).
There are many macroscopic objects which have
properties of a solid and properties of a wave.
Consider a bus, for instance. It is solid - it can hit
things, and they will bounce off it. But it has a
frequency - every 10 minutes at peak periods, say.
And frequency is definitely a property of a wave.
You can say this isn't really a property of a bus
because you need at least two buses, and preferably
several, to establish a frequency. And you'd be right,
but this wouldn't stop some people falsely attributing
the frequency to each single bus on the route.
Or consider the Earth. That is solid, more or less,
but it has at least two frequencies - one rotation
per day, one orbit per year.
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:aijsbe$g27$1...@newsg2.svr.pol.co.uk...
> > The appearance of homogeneity is approximate, not absolute,
> > and it only applies at large scales. In our immediate vicinity
> > we do not see a homogeneous collection of galaxies. Instead
> > in one direction we see the great attractor and several dense
> > compact superclusters containing many large elliptical radio
> > galaxies, consistent with them being older than our own cluster.
> > In the other direction we see very little in the way of dense
> > clusters in the immediate vicinity, but we do see some great
> > curving ribbons of galaxies which subtend enormous angles.
>
> Other than the limitations of the dust in the Milky way,
> I was under the impression we see such structures in all
> directions.
In all directions, yes. But their distances vary, as do some
of the incidental details. In one direction, as I said, there's
the great attractor. In the other direction we see a few
wispy chains of galaxies stretching across the sky, which
seem to be the outliers of the region dominated by the
great attractor. Beyond them we see one of the famous
bubble-like voids, and beyond them we see evidence
of another attractor which covers an even larger region
than the great attractor, but without such a dense central
concentration of matter. We see the Perseus-Pisces
supercluster, which follows a great sweeping arc across
more than 90 degrees of the sky. See
http://astrosun.tn.cornell.edu/courses/astro201/pps.htm
Look at the last diagram on the page, and ask youself
if that curve doesn't seem to be centred more or less
on our location. As if we are at the centre of some
vast structure. Spooky, yes?
..
> > If the overall displacement is large enough it can wrap
> > around. Some of the galaxies which appear to be near
> > the great attractor and to the left of it will actually be to
> > the right of it. Distant images which appear to be in the
> > opposite direction to the attractor will actually originate
> > from the vicinity of the attractor, or will be images of
> > the attractor. Does the conventional interpretation say
> > this?
>
> My impression is that it could do that only with a non-trivial
> topology but that is based only on what I have seen posted by
> others. I have no competence in GR.
If, as I assume, light can follow elliptical paths just like those
of a comet around a star, and if those paths are assumed to
be maximally straight paths in a curved spacetime, the resulting
topology is extremely non-trivial.
Steve Carlip
> Have you considered the possibility that my particular
> view *is* a better model?
What, quantitatively, does your model predict as the minimum
abundance of helium in an astronomical object? (Is there any
minimum? Why?) What does it predict for the abundances
of deuterium, helium 3, and lithium 7?
Does your model predict that the CMBR should have a thermal
spectrum? What thermalizes it? At what temperature? How
efficient is that process? (Quantitative answers, please.)
What, quantitatively, does your model predict for the dependence
of the CMBR temperature on red shift? Is there any dependence,
or is the temperature constant? If it is not, why bot? (Numbers,
please.)
What, quantitatively, does your model predict for the CMBR
spectrum? In particular, what deviations will MAP and Planck
see from a perfect thermal spectrum? (Here's your chance to
scoop the experiments!)
What, quantitatively, does your model predict for the duration
of supernovae light curves as a function of red shift?
What does your model predict for the abundance of neutral vs.
ionized hydrogen as a function of red shift? Should anything
special happen around z=6? If so, what, and why?
What, quantitatively, does your model predict for the two-point
correlation function of galaxies, as a function of scale?
What, quantitatively, does your model predict for the maximum
age of observable white dwarfs?
What, quantitatively, does your model predict for the red shift-
distance plot for high z supernovae?
Show your work.
If you can answer these questions, and you get results that agree
with observation, write up your results and submit them to Ap. J.
If your model can't make such quantitative predictions, then, no,
I won't consider ``the possibility that [your] particular view *is* a
better model.''
Steve Carlip
George Dishman
>
> > Let me turn it around and ask can you identify any macroscopic
> > class of object that obeys the same rules as QM? For example is
> > there something I could hold in my hand that would appear fuzzy
> > due to the Uncertainty Principle (rather than Marketing)?
>
> No I can't, and you make a good argument. Pretty big sticking point.
Like
> I said, sounds like the beginnings of a philosphical argument. But I
won't
> go there, sounds like the guys in sci.physics are tired of having their
> theories questioned by outsiders, crazies, and uneducated. Shame I got
that
> reply from Jeff Root, I was beginning to get interested in the research.
Robert, I know from emails that Jeff is a reasonable guy but he
clearly misread you. Please don't think the worse of him for it,
we all make mistakes as I frequently demonstrate.
George Dishman
That's the interesting one. A single electron fired at a pair
of slits will never (hardly ever?) hit a spot on a screen
beyond that is at a minimum of the interference pattern.
>and preferably
> several, to establish a frequency. And you'd be right,
> but this wouldn't stop some people falsely attributing
> the frequency to each single bus on the route.
>
> Or consider the Earth. That is solid, more or less,
> but it has at least two frequencies - one rotation
> per day, one orbit per year.
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:aijo2e$pjg$1...@newsg4.svr.pol.co.uk...
> > Despite my facetiousness, I do see these "competing
> > ideas" as serious. I just don't see them as alternatives.
>
> I see them as evidence that there is a willingness to
> consider all the alternatives within the limits of
> observation.
.. provided that they incorporate a Big Bang.
>
> > "Our equation doesn't work, so let's add a new factor
> > to it, and call it the cosmological constant". "No, let's
> > call it Dark Energy. That has a mysterious ring to it.
> > Cosmological constant sounds old-fashioned."
> > "Excuse me, chaps, but what do any of these terms
> > actually mean?" "They mean that our first equations
> > didn't work, so we had to add new factors to them.
> > If we didn't do that, we'd have to abandon our theory".
>
> The Cosmological Constant was in GR from the very first.
> In fact Einstein regretted putting it there, but it has
> been there for nearly a century nonetheless.
Einstein called it his greatest blunder, and he ought
to know. It stayed in place with a value of zero, because
that meant it having no effect, so it didn't matter whether
it was there or not. Most people assumed it wasn't there,
and wrote the equations without it. Its purpose was to allow
Einstein's equations to describe a static universe, and in the
context of that purpose it maybe made some sort of sense.
But Einstein soon realised that even with the constant his
universe was unstable, and would either collapse or blow
up. What he failed to realise was that the universe could
collapse and still be steady state, in the sense that the number
of galaxies and the average separation between them need
not vary greatly over time if new galaxies formed to replace
those that converged.
(This is a deliberate inversion of the usual description
of a steady state universe, where new galaxies form
to replace the galaxies that *di*verge).
> All that
> has happened is that we now have the technology to make
> a first stab at measuring it, and the result is not what
> was expected. That's progress. It doesn't mean we know
> what causes it yet, or even what the value is to any
> great accuracy.
Perhaps what causes it is a need for the apparent
vast universe that we see to conform to what would be
observed if the universe was actually comparatively small.
..
> The only 'embellishment' I know of is Guth's inflation.
> I agree, it is only the best we have so far, but that
> is true of all theories and always will be.
You don't think quintessence is an embellishment?
You don't think the sound waves rushing through the
universe prior to the formation of the CMB, and creating
acoustic peaks in the CMB, are an embellishment?
>
> > > The
> > > impression I get is not of a search for a better model but
> > > a desire to defend your particular view.
> >
> > Have you considered the possibility that my particular
> > view *is* a better model?
>
> The paper you quoted shows there are people considering
> this sort of idea. I am not capable of working at that
> level. However, a few things you say conflict with some
> basic rules and cause me to think you haven't done some
> basic groundwork. The most obvious is your repeated
> mention of closed elliptical paths for photons.
Maybe most theoreticians think that light can't follow
elliptical paths. But the important thing is what the light
does. Do you suppose that anyone has checked it (i.e.
performed an experiment to show whether or not light
can follow elliptical paths in a sufficiently massive
universe)?
>
> > > You should be as
> > > critical of your own model as you are of others.
> >
> > If my model is ever shown to be incompatible
> > with observations, I will certainly abandon it.
>
> Then you should show that the mass distribution that
> you propose produces elliptical orbits. That is the
> sort of test I would expect you to be doing.
Given Newtonian physics and a sufficiently
massive central attractor, light will certainly follow
elliptical orbits around it. Most of each orbit can be
elliptical, even if not all of the mass is concentrated
at the attractor (because, on the outside, any spherical
arrangement of mass acts just like a point mass).
I have shown this to my own satisfaction, and I consider
it to be obvious anyway.
Given GR, can this still be true? The problem here
is that GR seems designed to make only local physics
easy. The minute you try to describe a global situation
you get extreme complications, which can only be
mitigated by making extreme simplifying assumptions,
such as an assumption of total universal homogeneity.
GR is supposed to reduce to Newtonian physics in
a suitable limit, where objects are moving slowly and
gravity is not too strong. Well, I can't pretend that
gravitation isn't strong in a closed nonhomogeneous
universe, but it is a lot stronger in the vicinity of the
attractor than it is elsewhere. Also, all the material
objects in my model universe are moving relatively
slowly compared to the speed of light, again except
in the immediate vicinity of the attractor. So, we might
expect a close approximation to Newtonian physics
except in the immediate vicinity of the attractor.
>
> > Now, if I didn't treat the other models in the
> > same way, if in the face of overwhelming evidence
> > of their incorrectness I hunted desperately for some
> > unexplained factor which would make everything
> > right again, then I would certainly not be being as
> > critical of my own model as I am of those others.
>
> Where is this "overwhelming evidence"? All you have
> talked about so far is the non-zero value for the
> Cosmological Constant which has been a parameter
> waiting to be measured since GR was first published.
If that's all I've talked about, I've done a remarkable
job of padding it out to fill a lot of posts. :-(
..
> Ok here is a first stab. Your description is symmetrical
> about the central mass. This diagram shows five galaxies
> (or large structures of galaxies if you like) falling
> toward the central mass X.
>
> A
> D B E X
> C
>
> We are at B. D and E will appear to move away from us
> hence would be red-shifted but A and C will appear to
> be blue-shifted. However, we observe uniform redshift.
Not if A and C are reasonably close galaxies.
Several galaxies in the local group (more than half,
IIRC) are blueshifted.
It is only when we look outside the local group that we
observe all redshifted galaxies. So, suppose that A is
a galaxy that lies outside the local group. The light from
it, in reaching us, has to follow a path that is curved, partly
by the influence of the attractor X, and partly by passage
close to galaxies that are in our local group.
Even when the influence of the attractor is the only
significant influence, light path lengths can get longer
as galaxies approach the attractor. Take a look at
http://www.btinternet.com/~mtgradwell/ellipses.jpg
This shows one galaxy falling from a to b to c to d
while another falls from a' to b' to c' to d'. Light travelling
between the galaxies is assumed to follow an elliptical
path, solely under the influence of the attractor. The
effect of the galaxies on light paths is assumed to be
negligible. It should be obvious, I hope, that d-d' is
longer than c-c', which is longer than b-b', which is
longer than a-a'. Even as the galaxies converge on the
attractor and approach each other, the shortest light
path between them grows longer. Note that the
shortest light path is *not* a straight line, and in
extreme cases can be very far from straight.
In practice there will usually be other relevant
factors. Light will be deflected not only by the
great attractor but also by the galaxies that it passes
close by. As the galaxies converge on the attractor,
they become crowded closer together. Therefore
they will tend to impinge to an increasing degree on
the rays of light coming from more distant galaxies.
This will contribute to the redshift of those more
distant galaxies. I've avoided incorporating such
factors into the ellipses.jpg diagram, so that the
main mechanism is not obscured by minor details.
>
> Now I am sure you will say this is explained by the
> bending of the light, but I do not see how that can
> happen for all the observers in a circle at the same
> radius from X as B due to the symmetry.
I hope the diagram makes it clear. If not, please
point out the difficulty and I will draw more diagrams,
or do whatever else is necessary.
> --
> George Dishman
> The arrow of time points in many directions.
Martin Gradwell, mtgra...@btinternet.com
http://www.btinternet.com/~mtgradwell/
Joseph Lazio
>>> All of these "competing ideas" are different attempts to shore
>>> up one single flawed idea.
>>
>> You don't seem to be looking at the evidence and treating these as
>> serious alternatives that could explain whatever you see as 'flaws'
>> but dismiss them out of hand.
[...]
MG> "Our equation doesn't work, so let's add a new factor to it, and
MG> call it the cosmological constant". "No, let's call it Dark
MG> Energy. That has a mysterious ring to it. Cosmological constant
MG> sounds old-fashioned." [...]
The above comments are another reason why, IMHO, conversations with
you tend to peter out. The cosmological constant is not just "some
factor" that's invented to save face. It's an integral part of the
original equations. The problem had been, until recently, what was
its value? For lack of any evidence to the contrary, its value was
considered to be zero (or at least small). Now the evidence suggests
otherwise.
>> The impression I get is not of a search for a better model but a
>> desire to defend your particular view.
MG> Have you considered the possibility that my particular view *is* a
MG> better model?
Yes, and the problem is that your views don't seem to be in accord
with the evidence.
[...]
MG> Briefly, for those who haven't been following, I say that the
MG> universe is finite, closed, and inhomogeneous, with a central
MG> attractor.
Look at the distribution of radio galaxies. No evidence of
inhomogeneity. Look at *deep* redshift surveys (not the Harvard-CfA
work from the late 1980s). On large scales the distribution of
galaxies is homogeneous.
--
Lt. Lazio, HTML police | e-mail: jla...@patriot.net
No means no, stop rape. | http://patriot.net/%7Ejlazio/
sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html
Joseph Lazio
MG> If the overall displacement is large enough it can wrap
MG> around. Some of the galaxies which appear to be near the great
MG> attractor and to the left of it will actually be to the right of
MG> it. Distant images which appear to be in the opposite direction to
MG> the attractor will actually originate from the vicinity of the
MG> attractor, or will be images of the attractor. Does the
MG> conventional interpretation say this?
The conventional interpretation says that the topology of the Universe
is simple, in the sense that we do not see multiple images of the same
objects, at least on scales as large roughly as large as the horizon
(~ c*[age of Universe]).
Joseph Lazio
MG> And now, people want to patch up the theory, by adding a term or
MG> two into the equations.
Which term would this be? The cosmological constant? Remember that's
been around since GR was developed.
MG> They say that the inhomogeneities don't count because they're only
MG> a few hundred million light years across, and that's
MG> "small". Millions of galaxies is "small"!?
The number I carry around in my head, from a 1991 article by Peebles
et al., is that the Universe approaches homogeneity on scales of
roughly 40 Mpc (~ 120 million light years). The observable Universe
is roughly 4 Gpc (~ 12 billion light years) in radius. Thus, the
largest inhomogeneities in the observable Universe have sizes of
roughly 1% of the size of the observable Universe, and an individual
inhomogeneity occupies roughly 0.0001% of the volume of the observable
Universe.
A homogeneous Universe is a reasonable starting approximation.
Robert Gilster
obtuse form and it throws people off at times. A lot of times my posts in
these groups are more for thinking experiments than anything. I have
noticed that by writing out an argument to challenge a hot topic I can get
the biggest reaction and perhaps clarify or challenge what it is that
strikes me as wrong about whatever it was I was arguing against. In this
case I still don't totally buy the arguments but I can see how our model of
a subatomic particle could be off. The human brain shows a remarkable
tendency to categorize input into well defined pigeonholes. Look at how
many times the model for the atom has been redefined, I can imagine that a
smaller particle will have just as many permutations on what it "is" really.
> .
Martin Gradwell
Joseph Lazio <jla...@adams.patriot.net> wrote in message
news:lllm7kw...@adams.patriot.net...
..
> It's worth keeping some numbers in mind. The gravitational deflection
> of a light ray *grazing the Sun's surface* is less than 2 arcseconds
> (< 0.001 degrees). The deflection of a light ray at a few solar radii
> will be even smaller. Note that similar amounts of deflection are
> obtained from galaxies, even though they are much more massive than
> the Sun, because they are so much more diffuse.
That is the general assumption. But estimates of galaxy
masses have been going up and up, with the postulating of
"dark matter" of various types, and the realisation that all
galaxies probably contain supermassive central objects.
More importantly, the environment of a galaxy is totally
different from the immediate environment of the sun.
A galaxy can be surrounded by closely-neighbouring galaxies
of comparable size, some of which might even be less than one
galactic radius away. Compare this with the sun, where the
nearest star is more than 50 million solar radii away.
Light deflection v distance follows a roughly inverse law,
not inverse square; and the number of galaxies that can be
packed into a volume of space is roughly proportional
to the square of the volume. So, a cluster of galaxies can
cause significantly more bending than a single galaxy acting
alone can. Galaxies still have a bending effect on light even
if it does not graze their edges but passes by at some distance,
and even though each galaxy might have only a small effect
their total is not negligible.
> That's what the MOA Observer meant. In order to obtain the amount of
> deflection you want requires *far more* mass than is observed.
Haven't scientists been saying that there probably
*is* far more mass than is observed? That there has
to be, or GR wouldn't work? Haven't they worked
out that there must be lots of dark matter in galactic
haloes? Haven't they found supermassive objects
at the centres of galaxies, including our own?
Haven't they said that there must be considerably
more mass in the vicinity of the great atractor than can
be accounted for by the galaxies known to be there?
I would just go slightly further, postulating
supermassive objects even at the centres of
relatively small globular clusters (which would
explain how they can retain their integrity even
though they follow orbits which take them close
to the centre of their parent galaxy). I would also
say that the great attractor is not just an unusually
dense collection of galaxies - that there is a compact
object there which is more massive than thousands
of galaxies put together, making it sufficiently unique
to merit the label "singularity".
This may be different from what scientists are
saying, but it is tame compared to notions of
an entire universe trillions of times larger than what
we observe all originating in a space so small that
it makes an atom look vast in comparison.
And, it explains not just the observed large scale
homogeneity and isotropy, but also the observed
smaller scale deviations from homogeneity and
isotropy. And the apparent expansion, and the
acceleration of that expansion, and the "universe
older than expected" with iron-rich giant elliptical
galaxies surrounding quasars that are supposed
to have been young at the time when they emitted
the light we see today. And he variations in light
speed/fine structure constant reported elsewhere
in these groups. Etcetera, etcetera.
Martin Gradwell
> >
> > Measurement of the speed of light over a fixed,
> > measured distance has only ever been done at
> > or very near the earth's surface. Nobody has even
> > done it on the moon, let alone on another planet, or
> > in the vicinity of the sun, or at the core of the galaxy,
> > or in the depths of intergalactic space. Now, of
> > course, they don't need to.
>
> occasional posts regarding Pioneer 10.
Yes. I decided not to get involved until there was
some agreement about the sign of the observed
anomaly. I'm not sure if that ever happened. The
threads got too big for me to follow.
> Note that
> the time a signal takes to get from Earth to that
> craft and back is a crucial part of that measurement,
> to the extent that solid tides and tectonic plate
> movement of the DSN antennas has to be taken into
> account. The craft is currently over 80AU from the
> Earth. This is not a direct measurement by any means,
> but you should consider what effect a serious error
> in the speed of light would have on that.
Yes. If the acceleration of Pioneer towards the sun
is greater than anticipated, that could be because
Pioneer is closer to the sun than we think it is.
(Is that right? Have I got the sign right?)
How could Pioneer be closer to the sun than we
think it is? Easy. If the light that we assume to traverse
the distance between us and Pioneer at a fixed speed
actually slows down as it approaches the craft (because
it is climbing out of a gravitational well); if a return signal
starts off at the same reduced speed (because light speed
depends on depth in a gravitational well, not only for
light traversing the well but also for light that originates
in it) and accelerates until by the time it reaches us it has
the same speed as locally generated light; then the light
will take longer for the round trip than it would if its
speed was constant and equal to the speed of light in
Earth's vicinity.
The amount of bending of the signal will also have an
effect on the path length, and therefore on the time taken
by a round trip signal. This effect will vary depending on
the time of year, because there will be times when Pioneer
is on the opposite side of the sun to us, and times when it
is on the same side. I've not studied the reports, so I don't
know if this is properly taken into account. Presumably it is,
with Einsteinian light bending being assumed. Maybe it would
make a difference if Newtonian calculations were used
instead? This may be teaching granny to suck eggs,
but I think it's worth mentioning just in case it hasn't
been done.
The point I was making, though, is that since nobody
has measured the distance to celestial objects except
using EM (in particular, no-one has laid lots of rulers
end to end between here and Pioneer) any discrepancy
can be interpreted as either a variation in distance, or
a variation in lightspeed, or maybe a bit of both. Since
1983, it would have to be interpreted as a variation in
distance, because that's the agreed-upon rules; even
though that leads to non-Euclidean geometry, variation
in the fine structure constant, and other interesting physics.
G=EMC^2 Glazier
time zones as there are different strengths to billions of gravity
fields. To add to that thinking time is relative to a motionless
observer,and there are no areas of the universe that is standing still.
The fact is its gravity and motion that controls the length of the tick.
Bert
George Dishman
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1028658106.21945....@news.demon.co.uk...
> >
> > "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> > news:aim0b3$vv1$1...@newsg3.svr.pol.co.uk...
> > >
> > > Measurement of the speed of light over a fixed,
> > > measured distance has only ever been done at
> > > or very near the earth's surface. Nobody has even
> > > done it on the moon, let alone on another planet, or
> > > in the vicinity of the sun, or at the core of the galaxy,
> > > or in the depths of intergalactic space. Now, of
> > > course, they don't need to.
>
> is greater than anticipated, that could be because
> Pioneer is closer to the sun than we think it is.
>
> (Is that right? Have I got the sign right?)
Yes you have. The magnitude is about 25km over 8 years.
> How could Pioneer be closer to the sun than we
> think it is? Easy. If the light that we assume to traverse
> the distance between us and Pioneer at a fixed speed
> actually slows down as it approaches the craft (because
> it is climbing out of a gravitational well); if a return signal
> starts off at the same reduced speed (because light speed
> depends on depth in a gravitational well, not only for
> light traversing the well but also for light that originates
> in it) and accelerates until by the time it reaches us it has
> the same speed as locally generated light; then the light
> will take longer for the round trip than it would if its
> speed was constant and equal to the speed of light in
> Earth's vicinity.
If the light took longer than expected, it would appear
further away. However the situation is much more complex.
There are no direct measurements of the time because the
ranging system didn't work. Instead the position is found
by integrating the speed which is found from the Doppler
shift. That is almost unaffected by an error in the speed
of light. However they have to calculate the time of
transmission by using the position to work out the round
trip time. If the speed were apreciably different from
expected, that would be wrong and the location of the
transmitting station would be out due to the rotation of
the Earth. There are tiny residuals of that form in the
signal but it puts very tight limits on the speed. The
authors are finding perhaps centimetre to metre level
errors in the locations and that means the times are
within a few nanoseconds in a round trip of 22 hours
35 minutes. That is a very tight limit on the speed.
> The amount of bending of the signal will also have an
> effect on the path length, and therefore on the time taken
> by a round trip signal. This effect will vary depending on
> the time of year, because there will be times when Pioneer
> is on the opposite side of the sun to us, and times when it
> is on the same side. I've not studied the reports, so I don't
> know if this is properly taken into account. Presumably it is,
> with Einsteinian light bending being assumed. Maybe it would
> make a difference if Newtonian calculations were used
> instead? This may be teaching granny to suck eggs,
> but I think it's worth mentioning just in case it hasn't
> been done.
You should have a look. There is a section devoted to
alternatives and several different gravitational models
are discussed, including frequency changes due to bending.
To be honest I don't understand most of it but it will at
least show you the depth of thought that has been put into
it.
> The point I was making, though, is that since nobody
> has measured the distance to celestial objects except
> using EM
Ah, you didn't say that. Check the first paragraph
quoted in this post. In that case I would point out
that IIRC the Shapiro delay has been confirmed by
bouncing radar off Venus when close to conjunction.
The location is known independently from the orbital
dynamics so the speed has been confirmed 'in the
vicinity of the Sun'. We also regularly bounce
lasers off the Moon and Pioneer is beyond Pluto so
most of your list has been done.
>(in particular, no-one has laid lots of rulers
> end to end between here and Pioneer) any discrepancy
> can be interpreted as either a variation in distance, or
> a variation in lightspeed, or maybe a bit of both. Since
You really should have a look at the equations they use
to calculate the round-trip time. The paper is here
http://www.arxiv.org/abs/gr-qc?0104064
> 1983, it would have to be interpreted as a variation in
> distance, because that's the agreed-upon rules; even
> though that leads to non-Euclidean geometry, variation
> in the fine structure constant, and other interesting physics.
Martin Gradwell
> >
> > George Dishman <geo...@briar.demon.co.uk> wrote in message
> > news:1028505629.13216....@news.demon.co.uk...
> > >
> > > "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> > > news:aijo2e$pjg$1...@newsg4.svr.pol.co.uk...
> > ..
> > > > Despite my facetiousness, I do see these "competing
> > > > ideas" as serious. I just don't see them as alternatives.
> > >
> > > I see them as evidence that there is a willingness to
> > > consider all the alternatives within the limits of
> > > observation.
> >
> > .. provided that they incorporate a Big Bang.
>
> is observed.
Present lengthening of light paths is observed,
except in the vicinity of the observer. In a non
-Euclidean geometry (such as we get when we
assume that elliptical orbits are maximally straight
paths in a curved manifold) this does not have to
imply that the volume of space is increasing.
Furthermore, if we extrapolate backwards not
just the "expansion" of distant regions but also the
convergence in the local "gravitationally bound"
region, we arrive at an initial situation where there
was very little matter, practically a pure vacuum,
"here", but a dense concentration of matter
elsewhere.
The acceleration, if extrapolated backwards, shows
that we (that is, our galaxy) could have begun in a
near-vacuum with no noticeable velocity relative to
anything else in the vicinity, and the velocity only
came later as we came increasingly into the sphere
of influence of the Great Attractor.
> > > The Cosmological Constant was in GR from the very first.
> > > In fact Einstein regretted putting it there, but it has
> > > been there for nearly a century nonetheless.
> >
> > Einstein called it his greatest blunder, and he ought
> > to know. It stayed in place with a value of zero, because
> > that meant it having no effect, so it didn't matter whether
> > it was there or not. Most people assumed it wasn't there,
> > and wrote the equations without it.
>
> They assumed it's value would be zero, or at least had
> no evidence to justify any other value. There is a big
> difference.
There are no lions in my garden. The number of lions
in my garden is zero. Spot the difference. I suppose that
in the case of a zoo, which might be expected to have
lions, these statements might have different connotations.
"The number is zero" seems to imply it might be non-zero,
at some other time or in some other circumstances. Or
maybe it's non-zero and I miscounted. Or maybe the
zero is just a ball-park figure.
But *why* should the cosmological constant be non-zero?
Because it is? That seems to be the stock answer to almost
everything. Why can't any observation actually relate
to some other observation?
> ...
> > > The only 'embellishment' I know of is Guth's inflation.
> > > I agree, it is only the best we have so far, but that
> > > is true of all theories and always will be.
> >
> > You don't think quintessence is an embellishment?
>
> No, it is a name given to whatever is the cause of the
> non-zero Cosmological Constant. That factor has always
> been there.
Naming something is not the same as explaining it.
On the contrary, we now have a new mysterious
substance which seems to require explanation. It
isn't like any other known substance. We don't know
what it might look like, how we might find it or where.
It's only known property is that it makes the expansion
speed up.
But, if it is a substance, then presumably it can
have a distribution that is non-uniform (except on
suitably large scales of course, but that could mean
over regions that are a trillion light years across).
So now we can explain even a non-constant "constant",
by supposing that there is more quintessence in some
places than in others. Even if the acceleration was found
to be more pronounced in some directions than in others,
the theory would still be safe - in fact it could be said
to have predicted the non-uniformity. If the acceleration
is uniform, no problem - it predicted that too.
> > You don't think the sound waves rushing through the
> > universe prior to the formation of the CMB, and creating
> > acoustic peaks in the CMB, are an embellishment?
>
> No, they were predicted by the theory before they were
> measured.
According to Physics Today, July 2001
"The inflationary scenario also requires a harmonic
sequence of lesser acoustic peaks corresponding to
CMB fluctuations on ever-smaller angular scales."
There's no mention of acoustic peaks in Guth's "the
Inflationary Universe". On P216/217 it says "with
thermal radiation comes thermal fluctuations, the relentless
*unpredictable* jittering of hot matter". (my emphasis)
On P221 "Hawking found that the spectrum of density
perturbations predicted by inflation has a simple form:
It is _scale invariant_, meaning essentially that each
wavelength has the same strength."
Obviously predictions can keep changing all the time,
for entirely valid reasons, but this means that there can
be very few scenarios that haven't been predicted by
the inflationary scenario at some stage. The predictions
grow and change along with the observations, and it
isn't always clear which came first. Is this really
straightforward unembellished GR?
Interestingly, according to Google, prior to this
thread there has only been one mention of acoustic
peaks in sci.astro, in October 1999. There has
never been a mention of them in sci.astro.research.
...
> GR has been checked with light passing the Sun at high
> angles and gravitational lensing. The observed bending
> complies with GR and is greatest closest to the mass.
> For an elliptical orbit there is strong bending near
> the mass but also at the other end of the ellipse. That
> is entirely contrary to GR and in fact any theory of
> gravity that I know of.
Ever hear of a man named Isaac Newton?
Not a lot of people know it, but he had a theory
of gravitation. :-)
> I have asked a number of times what mass distribution
> you have calculated that produces a stable elliptical
> orbit for a photon in GR and you have not answered yet.
I use Newtonian calculations. When I first came to
usenet I was hoping that I would be able to learn
enough GR to transpose the basic ideas into a GR-
based model, which would be more likely to be taken
seriously in the current climate. Unfortunately, the
lesson seemed to be that GR was a package that
had to be accepted whole, complete with the
prevailing cosmological models. In particular, the
big bang and black holes were not optional.
Inhomogeneous cosmologies had been discredited
decades ago, apparently, but by experiments that
nobody would cite.
Light is affected by gravitation in the same way
that material objects are. Newton knew it. Einstein
showed it with his elevator gedanken. And yet,
light does loop-the-loops, or spirals, or unstable
circles, or hyperbolas, or, it seems, *anything*
except ellipses.
..
> > Given GR, can this still be true? The problem here
> > is that GR seems designed to make only local physics
> > easy.
>
> GR is designed to model what we observe.
Have you ever observed light looping-the-loop?
Or spiralling inexorably inwards under gravitational
influence? Have you ever observed *anything*
behave in this sort of way? Sure, satellites spiral
down in their final moments, but only under the
influence of atmospheric drag. Are photons retarded
by their progress through a spatial medium, present
even in a vacuum? Do they become "tired"?
(Be careful when replying. Aladar might be reading
this :-) )
> > GR is supposed to reduce to Newtonian physics in
> > a suitable limit, where objects are moving slowly and
> > gravity is not too strong.
> ^^^^^^^^^^^^^^^^^^^^^^^^^
>
> ... and the speed of light is infinite.
In other words, it doesn't really reduce to Newtonian
physics in any circumstances. Newton knew that the
speed of light was not infinite. He could have described
the elliptical or hyperbolic path that would be followed
by a corpuscle of light, resulting in objects being in
one position but appearing to be in another. *His*
formulas predicted bending of light by the sun, and
until 1915 the amount of bending predicted by Newton's
theory was exactly the same as the amount predicted
by Einstein. Which must mean that relativity, pre-1915
vintage, allowed light to follow elliptical paths (though
it would have described then as maximally straight paths
in a curved spacetime, I don't see how the predictions
could have differed in any essential way from those
of Newtonian physics).
> Nope, you said above where "gravity is not too strong".
> It is a poorer approximation closer to objects. Remember
> it shows up more in the orbit of Mercury than any other
> planet.
43 seconds of arc in one century. And that's displacement
of the *perihelion*, not displacement of the planet. The
planet needn't be more than 170 metres away from its
predicted position, after a century of observation.
This anomalous precession was apparently detected in
the 19th century, when good telescopes hadn't been
around for much more than a century, the best clocks
had a spring and a key to wind them up, there was
no photographic astronomy, all telescopes were
optical, and the best of them made Mercury look
like a vague blob.
That's all I've time for now. I know I'm falling
behind. I'll try to catch up later. Gotta go.
MOA Observer
I think you mean luminous mass because some scientists think that they have
observed dark matter indirectly.
Personally I'm not a believer in vast amounts of dark matter but I think
there may be a problem with gravitational theory but that is beside the
point.
Anyway one of the methods that cosmologists have used to indirectly find
dark matter is gravitational lensing. Cosmologists can get a good estimate
of the mass of a gravitational lens by the deflection of the source. The
deflection can be found very accurately if you have multiple images of the
source and the distances to the source and lens can be found via redshift
and luminosity. It has been calculated that there is a larger deflection
than can be accounted for by the luminous matter in the lens galaxy so the
conclusion was that there is extra dark mass in the lens galaxy. The extra
mass required for the observed deflection is consistent with the amount of
dark matter that is required to explain spiral galaxy rotation curves
(70-95%).
> That there has
> to be, or GR wouldn't work? Haven't they worked
> out that there must be lots of dark matter in galactic
> haloes? Haven't they found supermassive objects
> at the centres of galaxies, including our own?
Are you saying that we can expect larger deflections by gravitational
lensing due to the fact that there is more mass in the lens. If this is
what you are saying then you are correct up to a point but these
deflections are still small. I don't think dark matter in galaxies will be
enough to explain the lensing you are thinking of as current models of
lensing by galaxies and galaxy clusters use dark matter but still give
fairly small deflections.
>
> Haven't they said that there must be considerably
> more mass in the vicinity of the great atractor than can
> be accounted for by the galaxies known to be there?
>
> I would just go slightly further, postulating
> supermassive objects even at the centres of
> relatively small globular clusters (which would
> explain how they can retain their integrity even
> though they follow orbits which take them close
> to the centre of their parent galaxy).
Globular clusters are being torn apart as they pass through our galaxy and
some are expected to only have a few more passes in them before they
disintegrate. You said above that galaxies are sparsely populated but
globular clusters are comparatively dense with stars and their
"compactness" is enough to hold them together without supermassive objects
in their cores.
http://antwrp.gsfc.nasa.gov/apod/ap990225.html <-This APOD talks about
the dissolving globular cluster ngc6712.
Joseph Lazio
MG> Joseph Lazio <jla...@adams.patriot.net> wrote in message
MG> news:llsn1t7...@adams.patriot.net...
>> >>>>> "MG" == Martin Gradwell <mtgra...@btinternet.com> writes:
MG> They say that the inhomogeneities don't count because they're
MG> only a few hundred million light years across, and that's
MG> "small". Millions of galaxies is "small"!?
>> The number I carry around in my head, from a 1991 article by
>> Peebles et al., is that the Universe approaches homogeneity on
>> scales of roughly 40 Mpc (~ 120 million light years). The
>> observable Universe is roughly 4 Gpc (~ 12 billion light years) in
>> radius.
MG> The "Great wall" stretches more than 500 million light years
MG> across the sky (Guth, the Inflationary universe, ...). And, in
MG> order for us to perceive it as a wall, it must have (...) voids of
MG> a similar scale on either side of it. Voids are said by Guth to be
MG> "typically 150 million light years across". More recently there
MG> was a report of a discovery of a more distant sheet of galaxies
MG> 600 million light years across, IIRC. There is no reason to
MG> suppose that there won't be even larger structures at greater
MG> apparent distances.
The 2dF doesn't see them. <URL:http://msowww.anu.edu.au/2dFGRS/>.
(Also, for these purposes 120 million light years = 150 million light
years.)
Joseph Lazio
MG> Joseph Lazio <jla...@adams.patriot.net> wrote in message
MG> news:lllm7kw...@adams.patriot.net...
n
>> It's worth keeping some numbers in mind. The gravitational
>> deflection of a light ray *grazing the Sun's surface* is less than
>> 2 arcseconds (< 0.001 degrees). The deflection of a light ray at a
>> few solar radii will be even smaller. Note that similar amounts of
>> deflection are obtained from galaxies, even though they are much
>> more massive than the Sun, because they are so much more diffuse.
MG> That is the general assumption. But estimates of galaxy masses
MG> have been going up and up, with the postulating of "dark matter"
MG> of various types, and the realisation that all galaxies probably
MG> contain supermassive central objects.
First, the supermassive central objects at the centers of galaxies are
not important on galactic scales. The black hole at the center of the
Milky Way has a mass of 2.6E6 solar masses. The mass of the Milky Way
is something like 1E11 solar masses. In other words, the supermassive
object at the center of the Milky Way contributes about 0.002% of the
total mass of the Galaxy. Even the 1E9 solar mass black holes found
in the centers of some other galaxies don't contribute much more than
0.1% of the total mass of the galaxy (because these galaxies typically
tend to be more massive than the Milky Way).
Second, do you have any idea by how much estimates of galaxy masses
"have been going up and up"? The mass of the Milky Way has been known
for decades. Estimates for masses of galaxy clusters have increased,
but because of observations of gravitational lensing and X-ray
observations. The amount of gravitational lensing observed is way
less than what you require.
Third, even if I grant you the assertion that estimates of galaxy
masses have been "going up and up," it's still not enough for what you
want. Suppose the mass of a galaxy is wrong by a factor of 10. Then
instead of 1" of deflection, 10" of deflection is produced. Even so,
more than 100,000 galaxies would have to lie along the line of sight
to the background quasar in order for the typical deflection to reach
1 degree.
George Dishman
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1028660991.23496....@news.demon.co.uk...
> >
> > "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> > news:aimr0o$d6h$1...@newsg1.svr.pol.co.uk...
> > >
> > > George Dishman <geo...@briar.demon.co.uk> wrote in message
> > > news:1028505629.13216....@news.demon.co.uk...
> > > >
> > > > "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> > > > news:aijo2e$pjg$1...@newsg4.svr.pol.co.uk...
> > > ..
> > > > > Despite my facetiousness, I do see these "competing
> > > > > ideas" as serious. I just don't see them as alternatives.
> > > >
> > > > I see them as evidence that there is a willingness to
> > > > consider all the alternatives within the limits of
> > > > observation.
> > >
> > > .. provided that they incorporate a Big Bang.
> >
> > "within the limits of observation." Present expansion
> > is observed.
>
> Present lengthening of light paths is observed,
> except in the vicinity of the observer. In a non
> -Euclidean geometry (such as we get when we
> assume that elliptical orbits are maximally straight
> paths in a curved manifold) this does not have to
> imply that the volume of space is increasing.
However, there is no observational evidence for that
amount of bending, and AFAIK eliptical orbits are not
possible in GR. Hence "Present lengthening of light
paths is observed," is taken as expansion.
> Furthermore, if we extrapolate backwards not
> just the "expansion" of distant regions but also the
> convergence in the local "gravitationally bound"
> region, we arrive at an initial situation where there
> was very little matter, practically a pure vacuum,
> "here", but a dense concentration of matter
> elsewhere.
>
> The acceleration, if extrapolated backwards, shows
> that we (that is, our galaxy) could have begun in a
> near-vacuum with no noticeable velocity relative to
> anything else in the vicinity, and the velocity only
> came later as we came increasingly into the sphere
> of influence of the Great Attractor.
I see that as local conditions only. A dense region
dragging in a few million galaxies is just a drop in
the ocean in cosmological terms.
> > > > The Cosmological Constant was in GR from the very first.
> > > > In fact Einstein regretted putting it there, but it has
> > > > been there for nearly a century nonetheless.
> > >
> > > Einstein called it his greatest blunder, and he ought
> > > to know. It stayed in place with a value of zero, because
> > > that meant it having no effect, so it didn't matter whether
> > > it was there or not. Most people assumed it wasn't there,
> > > and wrote the equations without it.
> >
> > They assumed it's value would be zero, or at least had
> > no evidence to justify any other value. There is a big
> > difference.
>
> There are no lions in my garden. The number of lions
> in my garden is zero. Spot the difference. I suppose that
> in the case of a zoo, which might be expected to have
> lions, these statements might have different connotations.
> "The number is zero" seems to imply it might be non-zero,
> at some other time or in some other circumstances. Or
> maybe it's non-zero and I miscounted. Or maybe the
> zero is just a ball-park figure.
Last night I had a phone call from someone who said that
studies of DNA suggest horese might exist that have
stripes. I thought "I'll believe that when I see it" but
when the sun came up, there was a zebra outside my window.
It would be fair to say it was unexpected, by that is
different from saying that I invented the concept of
zebras in response to seeing one.
> But *why* should the cosmological constant be non-zero?
The stock answer to that one is "Don't know".
http://www.arxiv.org/abs/astro-ph?9812133
Check figure 7 and figure 9 in particular.
> Because it is? That seems to be the stock answer to almost
> everything. Why can't any observation actually relate
> to some other observation?
At the moment, we seem to see acceleration of remote
objects, but the measurements have a large uncertainty.
In the future I would hope we would constrain the curve
more tightly and perhaps that will give us hints. Perhaps
it won't follow the curve predicted by GR and then who
knows. In the meantime that is all conjecture and we
cannot discard GR until we have a replacement.
> > > > The only 'embellishment' I know of is Guth's inflation.
> > > > I agree, it is only the best we have so far, but that
> > > > is true of all theories and always will be.
> > >
> > > You don't think quintessence is an embellishment?
> >
> > No, it is a name given to whatever is the cause of the
> > non-zero Cosmological Constant. That factor has always
> > been there.
>
> Naming something is not the same as explaining it.
> On the contrary, we now have a new mysterious
> substance which seems to require explanation. It
> isn't like any other known substance. We don't know
> what it might look like, how we might find it or where.
> It's only known property is that it makes the expansion
> speed up.
>
> But, if it is a substance, then presumably it can
> have a distribution that is non-uniform (except on
> suitably large scales of course, but that could mean
> over regions that are a trillion light years across).
As part of GR, it would apply even between the Sun
and planets but would probably be too small to measure.
True they tend to evolve hand in hand.
>Is this really
> straightforward unembellished GR?
Until you change Einstein's equations, yes. The rules of
momentum has been understood since Newton but we still
have great difficulty predicting turbulent flow.
> Interestingly, according to Google, prior to this
> thread there has only been one mention of acoustic
> peaks in sci.astro, in October 1999. There has
> never been a mention of them in sci.astro.research.
Really? I remember some time ago suggesting to Aladar
that he try to predict the curve before the MAP results
came in. Maybe I used a different phrase.
> > GR has been checked with light passing the Sun at high
> > angles and gravitational lensing. The observed bending
> > complies with GR and is greatest closest to the mass.
> > For an elliptical orbit there is strong bending near
> > the mass but also at the other end of the ellipse. That
> > is entirely contrary to GR and in fact any theory of
> > gravity that I know of.
>
> Ever hear of a man named Isaac Newton?
> Not a lot of people know it, but he had a theory
> of gravitation. :-)
Yep, shame it doesn't work :-(
> > I have asked a number of times what mass distribution
> > you have calculated that produces a stable elliptical
> > orbit for a photon in GR and you have not answered yet.
>
> I use Newtonian calculations. When I first came to
> usenet I was hoping that I would be able to learn
> enough GR to transpose the basic ideas into a GR-
> based model, which would be more likely to be taken
> seriously in the current climate. Unfortunately, the
> lesson seemed to be that GR was a package that
> had to be accepted whole, complete with the
> prevailing cosmological models. In particular, the
I don't think that is true, but tensors, differential
geometry and Christoffel symbols were well beyond me.
> big bang and black holes were not optional.
> Inhomogeneous cosmologies had been discredited
> decades ago, apparently, but by experiments that
> nobody would cite.
Check Peebles "Principles of Physical Cosmology".
He devotes severl pages to it, shows relevant plates
and mentions a number of the large scale structures
you have discussed.
> Light is affected by gravitation in the same way
> that material objects are. Newton knew it. Einstein
> showed it with his elevator gedanken. And yet,
> light does loop-the-loops, or spirals, or unstable
> circles, or hyperbolas, or, it seems, *anything*
> except ellipses.
AFAIK in simple topology, away from a BH, the paths
are virtually straight in the conventional sense. The
most extreme effects I have seen are the Einstein cross
and the arcs typical of the Abell 2218 photo you cited.
What is possible in theory is another matter.
> > > Given GR, can this still be true? The problem here
> > > is that GR seems designed to make only local physics
> > > easy.
> >
> > GR is designed to model what we observe.
>
> Have you ever observed light looping-the-loop?
> Or spiralling inexorably inwards under gravitational
> influence? Have you ever observed *anything*
> behave in this sort of way? Sure, satellites spiral
> down in their final moments, but only under the
> influence of atmospheric drag.
Bubble/cloud chamber tracks, but that is hardly
relevant.
>Are photons retarded
> by their progress through a spatial medium, present
> even in a vacuum? Do they become "tired"?
> (Be careful when replying. Aladar might be reading
> this :-) )
http://www.arxiv.org/abs/astro-ph?0104382
Motion (expansion) meaured by time stretching of the
light curves accounts for 107% +/- 6% of the red shift.
> > > GR is supposed to reduce to Newtonian physics in
> > > a suitable limit, where objects are moving slowly and
> > > gravity is not too strong.
> > ^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> > ... and the speed of light is infinite.
>
> In other words, it doesn't really reduce to Newtonian
> physics in any circumstances. Newton knew that the
> speed of light was not infinite. He could have described
> the elliptical or hyperbolic path that would be followed
> by a corpuscle of light, resulting in objects being in
> one position but appearing to be in another. *His*
> formulas predicted bending of light by the sun, and
> until 1915 the amount of bending predicted by Newton's
> theory was exactly the same as the amount predicted
> by Einstein. Which must mean that relativity, pre-1915
> vintage, allowed light to follow elliptical paths (though
> it would have described then as maximally straight paths
> in a curved spacetime, I don't see how the predictions
> could have differed in any essential way from those
> of Newtonian physics).
Well remember that you get the same radius for a black
hole from Newton by calculating an escape velocity equal
to the speed of light. That means any photon that doesn't
hit the event horizon is on a hyperbolic path in Newtonian
physics, so how did you predict an elliptical path for a
photon over inter-galactic distances using Newton?
If you want to trim this discussion down, I think that
is the one aspect that seems crucial to your model and
which I cannot believe. All the rest tends to come from
this since hyperbolic orbits mean all distortion must
appear to us to be very close to the mass, no matter
what the degree of bending.
> > Nope, you said above where "gravity is not too strong".
> > It is a poorer approximation closer to objects. Remember
> > it shows up more in the orbit of Mercury than any other
> > planet.
>
> 43 seconds of arc in one century. And that's displacement
> of the *perihelion*, not displacement of the planet. The
> planet needn't be more than 170 metres away from its
> predicted position, after a century of observation.
>
> This anomalous precession was apparently detected in
> the 19th century, when good telescopes hadn't been
> around for much more than a century, the best clocks
> had a spring and a key to wind them up, there was
> no photographic astronomy, all telescopes were
> optical, and the best of them made Mercury look
> like a vague blob.
>
> That's all I've time for now. I know I'm falling
> behind. I'll try to catch up later. Gotta go.
Me too, this started with one comment regarding
linearity and has drifted further than I intended.
Jonathan Silverlight
<mtgra...@btinternet.com> writes
>
>George Dishman <geo...@briar.demon.co.uk> wrote in message
>news:1028660991.23496....@news.demon.co.uk...
snip
>>
>> ... and the speed of light is infinite.
>
>In other words, it doesn't really reduce to Newtonian
>physics in any circumstances. Newton knew that the
>speed of light was not infinite.
Did he actually know that when he was doing the work? It was only
discovered in 1675. That must have been an extraordinary revolution in
thinking, BTW.
>> Nope, you said above where "gravity is not too strong".
>> It is a poorer approximation closer to objects. Remember
>> it shows up more in the orbit of Mercury than any other
>> planet.
>
>43 seconds of arc in one century. And that's displacement
>of the *perihelion*, not displacement of the planet. The
>planet needn't be more than 170 metres away from its
>predicted position, after a century of observation.
>
>This anomalous precession was apparently detected in
>the 19th century, when good telescopes hadn't been
>around for much more than a century, the best clocks
>had a spring and a key to wind them up, there was
>no photographic astronomy, all telescopes were
>optical, and the best of them made Mercury look
>like a vague blob.
Are you saying it may be a mistake? I think you'll find it's been
confirmed with modern measurements, and extended to the other planets.
And ISTR that it's been observed in pulsar systems where the precession
is measured in degrees per year.
Martin Gradwell
..
> > Even when the influence of the attractor is the only
> > significant influence, light path lengths can get longer
> > as galaxies approach the attractor. Take a look at
> > http://www.btinternet.com/~mtgradwell/ellipses.jpg
> >
> > This shows one galaxy falling from a to b to c to d
> > while another falls from a' to b' to c' to d'. Light travelling
> > between the galaxies is assumed to follow an elliptical
> > path, solely under the influence of the attractor.
>
> path at the greatest distance from the attractor. That
> is the opposite of what we observe.
If we look at a cometary orbit, we see the highest
bend in the comet path at the closest approach to
the sun. This is because we do not see the other
end of the orbit, but we can infer from Newton's
laws and from the way some comets keep coming
back that their orbits are elliptical.
With light, we never actually see the path of
the light being bent. What we see is displacement
of an image e.g. of a distant star, from which we
can infer that the path has been bent. If what we
see on cosmic scales is compatible with light having
followed elliptical orbits, that is strong evidence
IMO that the light has indeed followed elliptical
orbits.
One sun is not sufficient to make light follow elliptical
orbits, but it's different when we consider the effect of
an entire universe full of matter on the path of light.
> >The
> > effect of the galaxies on light paths is assumed to be
> > negligible. It should be obvious, I hope, that d-d' is
> > longer than c-c', which is longer than b-b', which is
> > longer than a-a'. Even as the galaxies converge on the
> > attractor and approach each other, the shortest light
> > path between them grows longer. Note that the
> > shortest light path is *not* a straight line, and in
> > extreme cases can be very far from straight.
>
> I think you need to do some sums!
I manually added the dots and labels at the ends of
the curved line segments, but the curves themselves
were not hand drawn. They were drawn by a Delphi
program that assumes a light speed that depends only
on depth in the gravitational well of the attractor, in
accordance with Newtonian physics.
Here's a snippet to give you the flavour of it:
procedure TForm1.moveit;
begin
distsq:=(x*x+y*y);
ddx:=-x*100/(power(distsq,1.5));
ddy:=-y*100/(power(distsq,1.5));
dx:=dx+ddx;
dy:=dy+ddy;
x:=x+dx;
y:=y+dy;
form1.canvas.pixels[trunc(x)+200,trunc(y)]:=clred;
end;
This procedure is called repeatedly, and each
time it is called it adds a dot to the diagram, and
the dots combine to form ellipses.
To ensure that the ellipses have the right relative
proportions, I begin with an object at the bottom
of the diagram which is stationary relative to the
attractor at the top. I allow it to fall freely towards
the attractor for a while before deflecting its path
through 90 degrees so that it will thereafter follow
an elliptical path.
I could amend the program to work out the length
of each path, and the time taken to traverse it, in
fact I will do that if you want me to, but I really do
think it is obvious that d-d' is longer than c-c', etc.
..
> > I hope the diagram makes it clear. If not, please
> > point out the difficulty and I will draw more diagrams,
> > or do whatever else is necessary.
>
> Yes it does thanks. Now that I understand what you
> are thinking, it should be easy for you to find the
> mass and range of the GA and calculate the amount of
> bending between a and a'. I don't expect it to be
> sufficient to change a blue shift in to a red shift.
My program uses arbitrary units like pixels instead
of light years or parsecs. My main aim in producing
a diagram is to make sure that it illustrates my point
and is big enough to be visible but not too big to fit
on a page.
If the estimated mass of the attractor is not enough
to change a blue shift into a red shift over distances
at which we observe only redshifts, I would suggest
that this is either because the estimated mass of the
attractor is too low, and needs to be increased, or
because more local galaxies are also having an effect
(not shown on the latest diagram), which augments the
effect of the attractor, or both of the above.
Jeff Root
>> Light is affected by gravitation in the same way
>> that material objects are. Newton knew it. Einstein
>> showed it with his elevator gedanken. And yet,
>> light does loop-the-loops, or spirals, or unstable
>> circles, or hyperbolas, or, it seems, *anything*
>> except ellipses.
>
> AFAIK in simple topology, away from a BH, the paths
> are virtually straight in the conventional sense. The
> most extreme effects I have seen are the Einstein cross
> and the arcs typical of the Abell 2218 photo you cited.
> What is possible in theory is another matter.
animation at http://www.freemars.org/jeff2/BH3.htm which
shows light doing all the strange things he says it does.
This animation was based partly on textbook illustrations
and partly on my general knowledge of light, gravity, and
black holes, but the light path was not calculated, just
guessed at, so it may be way off. I would bet that it's
pretty close, but *that* doesn't prove anything. :-)
The one thing I would repeat to Martin, that you first said
and Joseph Lazio amplified, is that light is expected to bend
this way only when within a few kilometers of a stellar-size
black hole, and hardly bends at all when it is a few thousand
kilometers away. As long as the observational evidence
continues to be that the speed of light in vacuum is constant,
light cannot travel in an elliptical path.
Please address his argument about it being impossible to
measure changes in the speed of light, now that the speed of
light is used to define the standard of length. You are so
good at clearing up this kind of confusion. Although it is
the sort of argument that I have come to expect from Aladar,
JosX, Robert Winn, or Oriel36, in Martin's case I can hope
that he will follow and understand the explanation.
> Well remember that you get the same radius for a black
> hole from Newton by calculating an escape velocity equal
> to the speed of light. That means any photon that doesn't
> hit the event horizon is on a hyperbolic path in Newtonian
> physics, so how did you predict an elliptical path for a
> photon over inter-galactic distances using Newton?
sphere is at least as interesting as the final event horizon.
Any photon which hits the photon sphere falls in. A photon
at the photon sphere can avoid falling in only by being in an
upward or precisely horizontal trajectory, which is impossible
for a photon coming from outside that sphere. Any photon
*inside* the photon sphere must be in an upward trajectory to
escape. A photon just above the final event horizon must be
headed straight up to escape.
As the animation shows, even a beam of light aimed a bit to
the side of the photon sphere is doomed.
Spaceman
>We have to keep in mind that time is relative.
nope,
timing is relative,
time is absolute (or it's not a "scientific time" at all)
James M Driscoll Jr
Spaceman
http://www.realspaceman.com
Martin Gradwell
..
> > The Big Bang is a time-reversed variation on the
> > 19th-century theme that "if present trends continue
> > then Londoners will all soon be buried under a vast
> > pile of horse droppings". It takes a perceived trend
> > and extrapolates it to an illogical conclusion.
>
> closer in the past." It seems logical to me.
"We see things moving away from us, except locally.
Therefore everything was much closer in the past
except for the local galaxies". Doesn't that seem even
more logical?
A more realistic backward extrapolation would put
us initially in a great void, surrounded at a distance
of a few million light years by a dense shell of matter.
Over time much of that shell has apparently expanded
away from us, becoming less dense in the process,
but some parts have approached us and have become
the local group of galaxies, and have added to the
bulk of our own galaxy through mergers.
> > Of course this can only make even a dubious kind
> > of sense if the "expansion" is either decelerating or
> > proceeding at a fixed rate,
>
> No, it also makes sense if the rate is increasing, we
> just have a non-zero cosmological constant.
It might seem reasonable to assume that a uniformly
expanding cosmos was initially extremely dense
and compact. That is not the case if the "expansion"
is accelerating. Eddington assumed an accelerating
expansion and calculated an initial radius for the
universe of 1068 million light years or thereabouts.
*Not* a tiny fraction of the size of an atom. His initial
density, 1 hydrogen atom per 1580 cubic cm.,
was similarly non-incredible.
> >and if the universe is
> > homogeneous. So, it was confidently asserted that
> > the universe was indeed homogeneous,
>
> It is observed to be homogeneous as you yourself
> admit. You just think there is a different cause.
*Nearly* homogeneous. On a scale which should
only seem small to somebody from Texas.
>
> >and that it
> > was expanding at a decelerating rate.
>
> Yes, that was assumed until it could be measured.
It was not stated as an assumption. It was,
as I said, confidently asserted.
There were some people who believed in the
cosmological constant even after Einstein had
abandoned it. Eddington, for instance, was of the
opinion that the universe was expanding at an
accelerating rate, and as I said he calculated its
initial radius as 1068 million light years or so,
with a cosmological constant of 9.8*10^-55
cm^-2. But that was back in the 1920's.
More recent treatments have assumed either
implicitly or explicitly that the constant is zero
and the universe is expanding at a decreasing
rate. E.g. in Stephen Hawking's "Brief History":
"Even Einstein .. was so sure that the universe
had to be static that he modified his theory to
make this possible, introducing a so-called
cosmological constant into his equations".
It is clear that Hawking doesn't see the constant
as an essential, integral part of GR.
".. Only one man, it seems, was willing to take
general relativity at face value, and while Einstein
and other physicists were looking for ways of
avoiding general relativity's prediction of a nonstatic
universe, the Russian physicist and mathematician
Alexander Friedmann instead set about explaining it."
".. there are in fact three different kinds of model
that obey Friedmann's two fundamental assumptions
[of homogeneity and isotropy].
In the first kind (which Friedmann found) the universe
is expanding sufficiently slowly that the gravitational
attraction between the different galaxies causes the
expansion to slow down and eventually to stop."
"In the second kind of solution, the universe is expanding
so rapidly that the gravitational attraction can never
stop it, though it does slow it down a bit".
"Finally, there is a third kind .. the speed at which
the galaxies are moving apart gets smaller and smaller,
although it never quite reaches zero".
Three models, all decelerating. The only models,
it is implied, that are consistent with GR and with
assumptions of isotropy and homogeneity.
"But which Friedmann model desctribes our universe?
Will the universe eventually stop expanding and start
contracting, or will it expand forever? To answer this
question we need to know the present rate of expansion
of the universe and its present average density."
Since it was supposed that we were close to finding
exact answers to these questions, for decades the
claim was that we were on the verge of discovering
whether or not there would be a big crunch.
Note that Eddington's model is excluded from
consideration nowadays because it does not include
the obligatory Big Bang. Neither does Einstein's
static universe.
..
> > How much sooner could the acceleration have
> > been discovered, if everybody hadn't "known",
> > for certain, that the expansion was decelerating?
>
> Not much, there were no instruments capable of
> making such measurements until quite recently.
And perhaps no great interest in making such
instruments, if there was no perceived need for them.
..
> Since the universe is probably infinite, my opinion
> is that the entire observable region of >10 billion
> light years is infinitesimally small in comparison.
Therefore, if the observable region had turned out to
be extremely inhomogeneous, the notion of universal
homogeneity on some larger scale would still have
been unscathed. It is an unfalsifiable notion. And
what makes you think that the universe is probably
infinite?
...
> > Our own local group of galaxies is collapsing into itself.
> > It is likely that it will eventually be a single elliptical radio
> > galaxy, like many of the galaxies that are nearer to the
> > attractor. It recapitulates their history.
> >
> > It is being drawn towards the attractor, along with
> > a very large number of galaxies over a region that is
> > hundreds of millions of light years across. That is not
> > a minor local disturbance, unless you apply very broad
> > definitions of "minor" and "local". But we are supposed
> > to believe that we are not being sucked in, because the
> > Hubble expansion trumps the pull of the attractor.
>
> I don't understand the last part. The evidence suggests we
> are being drawn in as I said. The GA effect is greater than
> the Hubble flow.
I agree that we are being drawn in. But the evidence
does not suggest that we are being drawn in (in the
sense of getting closer to the attractor), unless it is
properly interpreted. We do not see blueshifted galaxies
in the vicinity of the attractor. If you have read anything
that suggests otherwise, I'd really appreciate a reference.
The usual notion is that the blueshift indicates that we are
receding from the attractor, although our recession has
been slowed down by its influence. This influence does
"draw us in", in the sense that it deflects us relative to the
Hubble flow, but this effect is not greater than that of the
flow.
Oriel36
> Joseph Lazio <jla...@adams.patriot.net> wrote in message
> news:lllm7kw...@adams.patriot.net...
> ..
> > It's worth keeping some numbers in mind. The gravitational deflection
> > of a light ray *grazing the Sun's surface* is less than 2 arcseconds
> > (< 0.001 degrees). The deflection of a light ray at a few solar radii
> > will be even smaller. Note that similar amounts of deflection are
> > obtained from galaxies, even though they are much more massive than
> > the Sun, because they are so much more diffuse.
>
> That is the general assumption. But estimates of galaxy
> masses have been going up and up, with the postulating of
> "dark matter" of various types, and the realisation that all
> galaxies probably contain supermassive central objects.
So relativistics offshoots end up looking for 'aether' or its
newfangled term "dark matter" anyway.
The problem is that if observational anomalies exist within our solar
system (orbit of Io) due to the observational limitation natures
imposes how in the hell are you going to judge correctly what the
actual size,structure and motion of the rest of the cosmos is.
Galactic formation stopped at a particular stage of Universal
development where rotation would have played a role in their physical
structure at a limit where conditions would have allowed matter to
appear just as cyclonic weather systems develop under favorable
conditions such as in the hurricane season.Newton applied ideas of
swing buckets and sailors on ships to get his point across in a
general way so who would object to applying the same loose analogies
of developing storm systems with galactic formation,surely the
imagination has not died here altogether.
>
> More importantly, the environment of a galaxy is totally
> different from the immediate environment of the sun.
> A galaxy can be surrounded by closely-neighbouring galaxies
> of comparable size, some of which might even be less than one
> galactic radius away. Compare this with the sun, where the
> nearest star is more than 50 million solar radii away.
>
> Light deflection v distance follows a roughly inverse law,
> not inverse square; and the number of galaxies that can be
> packed into a volume of space is roughly proportional
> to the square of the volume. So, a cluster of galaxies can
> cause significantly more bending than a single galaxy acting
> alone can. Galaxies still have a bending effect on light even
> if it does not graze their edges but passes by at some distance,
> and even though each galaxy might have only a small effect
> their total is not negligible.
>
> > That's what the MOA Observer meant. In order to obtain the amount of
> > deflection you want requires *far more* mass than is observed.
Don't trust your visual senses,this is what Newton's message was and
given that he was prescient in speculating on a galactic center
perhaps you should revisit what he actually said in terms of celestial
structure and motion.The point is that you cannot directly infer how
galaxies move wrt to each other and what the actual structure is.
"But we my distinguish rest and motion, absolute and relative, one
from the other by their properties, causes and effects. It is a
property of rest, that bodies really at rest do rest in respect to one
another. And therefore as it is possible, that in the remote regions
of the fixed stars, or perhaps far beyond them, there may be some body
absolutely at rest; but impossible to know, from the position of
bodies to one another in our regions whether any of these do keep the
same position to that remote body; it follows that absolute rest
cannot be determined from the position of bodies in our regions"
>
> Haven't scientists been saying that there probably
> *is* far more mass than is observed? That there has
> to be, or GR wouldn't work? Haven't they worked
> out that there must be lots of dark matter in galactic
> haloes? Haven't they found supermassive objects
> at the centres of galaxies, including our own?
> Haven't they said that there must be considerably
> more mass in the vicinity of the great atractor than can
> be accounted for by the galaxies known to be there?
>
> I would just go slightly further, postulating
> supermassive objects even at the centres of
> relatively small globular clusters (which would
> explain how they can retain their integrity even
> though they follow orbits which take them close
> to the centre of their parent galaxy). I would also
> say that the great attractor is not just an unusually
> dense collection of galaxies - that there is a compact
> object there which is more massive than thousands
> of galaxies put together, making it sufficiently unique
> to merit the label "singularity".
Put two and two together and associate accelerating expansion with the
apparent rush of galaxies towards the great attractor,the chances are
that while never being capable of discerning Universal rotation
directly by instrumentation or sight it is possible to put at least
two pieces in a very difficult jigsaw puzzle together.
Martin Gradwell
followups - I suspect the conversation is drifting away
from relevance to those groups. MG.]
George Dishman <geo...@briar.demon.co.uk> wrote in message
news:1028662526.24266....@news.demon.co.uk...
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:aim40c$fqu$1...@newsg2.svr.pol.co.uk...
..
We see the Perseus-Pisces
> > supercluster, which follows a great sweeping arc across
> > more than 90 degrees of the sky. See
> > http://astrosun.tn.cornell.edu/courses/astro201/pps.htm
> > Look at the last diagram on the page, and ask youself
> > if that curve doesn't seem to be centred more or less
> > on our location. As if we are at the centre of some
> > vast structure. Spooky, yes?
>
> Not really, it is the weak anthropic principle. We live in
> a galaxy and there are no galaxies in a void by definition.
> Spookily, all galaxies seem to be in structures of galaxies.
Did you look at the diagram? the last one on the page.
http://astrosun.tn.cornell.edu/courses/astro201/images/ppcone_ridge.gif
is the url of the image if you want to see it on its own,
without distractions. The anthropic principle might give
us a reason for expecting to be in a structure of galaxies.
It does not suggest that this structure should be surrounded
by other structures, concentric shells of galaxies centred
approximately on our location. That would require a very
*strong* anthropic principle, or the crystal spheres of
Ptolemaic cosmology.
..
> > If, as I assume, light can follow elliptical paths just like those
> > of a comet around a star, and if those paths are assumed to
> > be maximally straight paths in a curved spacetime, the resulting
> > topology is extremely non-trivial.
>
> On the other hand, I think the idea that light can follow
> closed elliptical paths in GR is nonsense and contrary to
> the observational evidence that supports GR. I think you
> ignore this test to protect your idea and that is
> unscientific.
I've seen diagrams depicting light paths in the vicinity
of a black hole, and in grazing passage close to the sun,
or close to a galaxy acting as a gravitational lens. They
tend to be hyperbolae except when they pass *very*
close to a black hole, in which case we get these strange
spirals and things. But, what is the shape of the path of
light which circumnavigates a closed universe?
In the case of a homogeneous universe, which
is the only cosmology ever considered nowadays,
the question is practically meaningless. A light
beam follows a maximally straight path which cannot
deviate to left or right, or up or down, because there
are no concentrations of mass that might cause that
to happen. Nevertheless it wraps round somehow,
so that an observer can "see the back of his head".
This situation is not properly depictable unless you
have some sheets of five-dimensional paper to draw
it on.
We can suppress a few dimensions and get the
famous balloon with pennies stuck on it analogy,
and with the balloon being spherical the maximally
straight paths on it are great circles which are, well,
circular. But the insights gained from studying a
balloon don't necessarily all transfer up to a higher
number of dimensions.
Remember that it isn't just the null geodesics
followed by light that are said to be maximally
straight in GR. So, too, are the paths of any
freely falling test objects, and these can look
remarkably elliptical to the untrained eye.
Remember, too, that Lorentz transformation
means that a circular orbit around a stationary
centre can look like an elliptical orbit around
a rectilinearly moving centre, and vice-versa.
What would be the shape of a closed orbit in a
very inhomogeneous universe, with much of the
mass concentrated in one place, according to GR?
Is there any reason why it cannot be depicted as
elliptical, perhaps with some anomalous precession?
If not, why not? By elliptical, I mean having the
appearance of a flattened spiral in a spacetime
diagram, so that the projection of the orbit onto a
spacelike slice of the universe would be an ellipse.
The spacelike slice can be depicted as flat even
if GR says it isn't "really" flat, in much the same
way as the earth can be depicted as flat in a
Mercator's projection or polar projection map.
Martin Gradwell
George Dishman <geo...@briar.demon.co.uk> wrote in message
news:1028667690.13441....@news.demon.co.uk...
> Sorry I missed this one.
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:aijr95$me3$1...@newsg1.svr.pol.co.uk...
> >
> > George Dishman <geo...@briar.demon.co.uk> wrote in message
> > news:1028383994.11938....@news.demon.co.uk...
> > >
> > > If the great attractor was responsible
> > > for significant bending at 90 degrees to its position in the sky,
> > > the majority of galaxies should appear in that hemisphere and we
> > > should see large arcs at many degrees away from the GA centred
> > > on it.
> >
> > We do see large arcs at many degrees from the GA and
> > centred on it. The Perseus-Pisces supercluster is one such arc.
>
> That is a cluster of separate galaxies. With the effect you
> are suggesting we should see indiviual galaxies stretched
> into arcs tens of degrees long at 90 degrees to the location
> of the Great Atractor. We do not see that.
The opposite edges of a distant galaxy are not widely
separated in our field of view. If a large section of that
field of view was subject to consistent stretching (instead
of just a tiny patch being stretched, which includes one
galaxy and nothing else) then the two ends of the resulting
image of the distant galaxy will still be close together.
If the overall stretch is 50%, say, then images of galaxies
over a sizeable region will each be stretched 50%.
That would not be sufficient to make an image of a single
distant galaxy occupy an arc tens of degrees long.
And if in a particular region there is also 50% stretch
in a direction at right angles to the direction of the first
stretch, there will be practically no distortion at all, just
magnification, for galaxies that happen to be in such a
region. Which would mean no obvious evidence of
lensing, for some of the galaxies most affected by it.
Consider bending of starlight that passes the sun.
This causes the images of stars to be displaced.
It does not noticeably stretch the images of the stars.
They still appear to be pointlike. If we could
resolve their discs, they would still be disclike despite
the lensing. They would not be stretched into long arcs.
There could just possibly be a galaxy situated at a focal
point so from our viewpoint an image of it is stretched
out to fill much of the sky. If that was so, it is unlikely that
we would notice it. Distant galaxies are faint enough to
be difficult to spot even if the light from them hasn't
been smeared all over the sky.
G=EMC^2 Glazier
universe than these mini-bangs can make the universe continual.The old
stuff recycled and ready to start new again.This could screw a lot of
theories up,but that's life. Bert
Martin Gradwell
> >>>>> "MG" == Martin Gradwell <mtgra...@btinternet.com> writes:
>
> MG> Joseph Lazio <jla...@adams.patriot.net> wrote in message
> MG> news:lllm7kw...@adams.patriot.net...
> Third, even if I grant you the assertion that estimates of galaxy
> masses have been "going up and up," it's still not enough for what you
> want. Suppose the mass of a galaxy is wrong by a factor of 10. Then
> instead of 1" of deflection, 10" of deflection is produced. Even so,
> more than 100,000 galaxies would have to lie along the line of sight
> to the background quasar in order for the typical deflection to reach
> 1 degree.
If each galaxy produced 10" of deflection, just 360 of them
could produce a deflection of 1 degree, but they would have
to be lined up just right. 100,000 would be almost enough
to bend the light right round in a full circle. Still, I admit it is
*extremely* unlikely that there would be 100,000 galaxies
along the line of sight, each close enough and massive enough
to cause 10" of deflection, and all lying on the same side
of the line of sight so that their effect is cumulative.
Here's a diagram of light travelling from galaxy A to galaxy B
A------------------------------------------------->B
C
D E
F G H
I J K L
...
It just grazes galaxy C, at a distance of one galactic radius,
and this causes a small deflection, 10 arcseconds, say.
(I was going to say 2, but if you're happy with 10... :-) )
It passes D and E at a greater distance, 2 galactic radii.
D and E each only cause 5 arcsecond of bending, but their
combined effect is the same as that of C.
F, G and H each only cause 3.33 arcseconds bending, but
there are three of them, so again they cause a total of 10
arcseconds bending. I, J, K and L each cause 2.5 arcsec.
bending and there are 4 of them. Another 10 arcseconds
in total. And so on.
Galaxies C .. L between them cause 40 arcseconds of
bending. That's 10 galaxies, only one of which is very close
to the line of sight from A to B.
It may look like galaxies I..L are packed together
more closely than galaxies D..E, say, but that is because
a 3-D situation is being depicted on a 2-D screen.
In reality the galaxies can range above and below the
plane of the screen, so there is more space available
for the packing of galaxies at greater distances from
the line of sight A B.
The point is, galaxies don't have to be right on
the line of sight to have a cumulative effect that is
very noticeably larger than the effect of a single
galaxy.
Even so, it would take a very large number of
milky-way sized galaxies to make the universe
closed in the way that I envisage. Rather more,
probably, than we could expect to find in a region
a billion light years or so across, which is what
I think the universe is. But I think that there is a
significantly higher matter density in the immediate
vicinity of the attractor than there is here, and
that the attractor itself is rather more than just
an unusually dense collection of unusually
massive galaxies.
If the great attractor was just a uniformly dense
set of galaxies surrounded by a void and undergoing
gravitational collapse, the collapse would be uniform.
There would be blue shifts everywhere in that case.
But in fact objects which are closer to the attractor
than we are accelerate away from us. The closer they
are to the attractor, the more they accelerate away.
This shows, in my opinion that there is something
more massive than thousands of galaxies put together,
right at the heart of this matter-dominated region.
Galaxies continue to accelerate right up until the time
when they hit it. It is primarily responsible for the
universe being closed. In comparison the galaxies,
even the very massive old galaxies in the immediate
vicinity of the attractor, just have a small modifying
effect on the pattern established by the attractor.
They introduce just enough irregularity into the light
orbits to make the overall pattern difficult to spot
if you aren't looking for it.
Dale A Trynor
> [alt.fan.jai-maharaj and soc.culture.indian removed from
> followups - I suspect the conversation is drifting away
> from relevance to those groups. MG.]
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1028662526.24266....@news.demon.co.uk...
[snip]
>
> close to a black hole, in which case we get these strange
> spirals and things. But, what is the shape of the path of
> light which circumnavigates a closed universe?
>
> In the case of a homogeneous universe, which
> is the only cosmology ever considered nowadays,
> the question is practically meaningless. A light
> beam follows a maximally straight path which cannot
> deviate to left or right, or up or down, because there
> are no concentrations of mass that might cause that
> to happen. Nevertheless it wraps round somehow,
> so that an observer can "see the back of his head".
> This situation is not properly depictable unless you
> have some sheets of five-dimensional paper to draw
> it on.
I have tried to examine how a close up and near the photo sphere, astronaut
would attempt to measure this curvature in a light beam as it traveled
around a black hole. It started to become apparent that the same effects of
gravity that would bend light might also effect any object made of matter
that could be used to detect this bending. Remember that for the light to
already be traveling in a curved path and also travel trough the space
craft in this similar path and or orbit, any detectable bulging and or
curving in the light path, could be argued as a possible equivalence
principle violation. It is important that the craft also be gyroscope
stabilized for this to work as a valid question. Curvature being relative,
any opinions on this.
>
>
> We can suppress a few dimensions and get the
> famous balloon with pennies stuck on it analogy,
> and with the balloon being spherical the maximally
> straight paths on it are great circles which are, well,
> circular. But the insights gained from studying a
> balloon don't necessarily all transfer up to a higher
> number of dimensions.
You will need to examine the theory I have been commonly posting on. It
deals with the creation of both space and time and I have finally found a
way of essentially proving it. The theory I have deals with the idea that
time dilation when its caused by gravity, should cause space and or
distances to expand, because of the contracting of all objects that could
otherwise be used to measure these distances with. You might love how it
deals with the idea that the photosphere could indeed become a flat surface
_ literally _ . In the theory it becomes indistinguishable if ones measures
of distance have become less or the distances actually more. Later on show
arguments for it actually being more space and not just a shorter measure
of the same space i.e., distance's. When you get closer to a black hole all
of its contents start to measure as farther away and more distributed, it
reaches a point were an up close observer could not any longer observe a
black hole as we do. This could mean that if black holes are universe like,
they may also have different prospective on how much matter one needs to be
in the one place at one time to cause the orbit of light to return.
I have not been able to explain how this would give a universe that
continues to expand, unless more matter was being added from outside.
I will update my site in a few weeks as I have just regained access to it
again. However I will re-post the simplified method of proving this theory
if you request it, as its about 100 lines. I would have done this for you
now, if I had not been posting it so much that I feel people here must be
beginning to become bored with me repeating myself. Despite its simplicity,
no one here has been able to say it was wrong "here, because", so you will
just have to judge for yourself.
www.alternatescience.com
Martin Gradwell
MOA Observer <phy...@phys.canterbury.ac.nz> wrote in message
news:3D55526B...@phys.canterbury.ac.nz...
> Martin Gradwell wrote:
..
> > Haven't scientists been saying that there probably
> > *is* far more mass than is observed?
>
> I think you mean luminous mass because some scientists think that they
have
> observed dark matter indirectly.
Depends what you mean by observed indirectly, I think.
An "indirect observation" is actually an inference. It requires
a framework of theory and assumptions. For instance,
gravitational rotation curves which are only compatible with
galaxies being more massive than their observed luminous
component could be called indirect observations of dark
matter, but to do so is to assume implicitly that the theory
which requires the dark matter is correct. It also involves
an assumption that the rotation curves we put together from
observations of redshift are accurate, i.e. that redshift is
an accurate measure of velocity, and that the galaxies being
observed are pretty nearly as large and as distant as we
assume them to be.
Every time cosmic distance scales are revised upwards,
it affects everything else. If the distance of a particular
galaxy is revised upwards, then presumably it is also larger
than we though it was - unless we come to realise that it
is subject to magnification by lensing, in which case it might
be smaller than we previously thought. Our estimated counts
of stars in distant galaxies must depend on assumed size. Etc.
> Personally I'm not a believer in vast amounts of dark matter but I think
> there may be a problem with gravitational theory but that is beside the
> point.
> Anyway one of the methods that cosmologists have used to indirectly find
> dark matter is gravitational lensing. Cosmologists can get a good estimate
> of the mass of a gravitational lens by the deflection of the source. The
> deflection can be found very accurately if you have multiple images of the
> source and the distances to the source and lens can be found via redshift
> and luminosity. It has been calculated that there is a larger deflection
> than can be accounted for by the luminous matter in the lens galaxy so the
> conclusion was that there is extra dark mass in the lens galaxy. The extra
> mass required for the observed deflection is consistent with the amount of
> dark matter that is required to explain spiral galaxy rotation curves
> (70-95%).
Collaborative evidence. Two observations suggesting the
same thing. That strongly suggests that there is dark matter.
There is however the proviso that our distance measurements
to both lensing and lensed galaxies will be approximate,
especially in the case of the lensed galaxy because this will
be distorted, and the distortion will affect the observed
luminosity.
I think there is dark matter, but not the mysterious
stuff, totally different from any matter we might have
knowledge of, that some cosmologists theorise.
Just dust and gas and lots of objects that would
have been stars if they had been big enough to ignite,
and supermassive objects at the centres of clusters.
>
> > That there has
> > to be, or GR wouldn't work? Haven't they worked
> > out that there must be lots of dark matter in galactic
> > haloes? Haven't they found supermassive objects
> > at the centres of galaxies, including our own?
>
> Are you saying that we can expect larger deflections by gravitational
> lensing due to the fact that there is more mass in the lens. If this is
> what you are saying then you are correct up to a point but these
> deflections are still small. I don't think dark matter in galaxies will be
> enough to explain the lensing you are thinking of as current models of
> lensing by galaxies and galaxy clusters use dark matter but still give
> fairly small deflections.
I think larger-than assumed deflection, caused by galaxies
being more massive than previously thought, is just one factor
among several that lead to the universe being closed. Elliptical
galaxies tend to be both more massive and more compact
than spiral galaxies like our own. Particularly in the vicinity
of the attractor, there are many galaxies that are both more
compact and more massive than those we see locally.
The compact objects at the centres of elliptical galaxies
aren't just more massive in absolute terms than the one
at the centre of our galaxy; they are also a larger percentage
of the total galaxy mass. I think that this will be especially
true of those galaxies in the immediate vicinity of the attractor,
and that the attractor itself is a compact supermassive object
which is as massive as thousands of ordinary galaxies put
together. That is why ordinary galaxies continue to accelerate
towards it right until the moment that they hit it. In accelerating
towards it they merge, and that is why they become more
massive in the vicinity of the attractor.
Next, I think it isn't generally realised how much
light bending can be caused by galaxies that aren't
on the direct line of sight. They may individually
cause less deflection than a galaxy that is right on
the line of sight, but there's a lot more of them, and
their cumulative effect is not negligible. See my
answer to Joseph Lazio on this subject in this thread
http://groups.google.com/groups?selm=aj77pc%24g2j%241%40news5.svr.pol.co.uk
Finally, if there is bending on the scale that I suppose,
then it will create various optical illusions. It will make
it look as if there are sheets of galaxies that peel off
from the main matter-dominated region surrounding the
attractor, and which connect it to more distant attractors,
enclosing bubble-like voids in doing so. The galaxies
which appear to be in these sheets are actually part
of the compact spherical arrangement of galaxies in
the matter dominated region surrounding the attractor.
If this is not realised, then estimates of the size and
compactness of that region are bound to be
underestimates.
> > Haven't they said that there must be considerably
> > more mass in the vicinity of the great atractor than can
> > be accounted for by the galaxies known to be there?
> >
> > I would just go slightly further, postulating
> > supermassive objects even at the centres of
> > relatively small globular clusters (which would
> > explain how they can retain their integrity even
> > though they follow orbits which take them close
> > to the centre of their parent galaxy).
>
> Globular clusters are being torn apart as they pass through our galaxy and
> some are expected to only have a few more passes in them before they
> disintegrate.
Globular clusters are supposed to be among the oldest things
in the universe. The ones orbiting our galaxy are supposed to be
much older than their parent galaxy, which raises the question
of what they actually got up to before our galaxy was formed.
And yet, these clusters are being torn apart now. Is it
just a coincidence that we happen to live at a time when
the oldest objects in the universe are being torn apart?
I think not.
Every time a globular cluster emerges from the plane
of the parent galaxy, it starts to fall apart. Most of
the stars in it will not have escape velocity, but every
so often there will be a redistribution of kinetic energies
such that one star _does_ attain escape velocity. The
stars that remain behind will have less total kinetic
energy, but they will also be part of a smaller cluster
with a smaller escape velocity than previously.
By the time the cluster is re-entering the plane of the
galaxy it will be a shadow of its former self. But then
it becomes replenished. It picks up a new frosting of
old stars, from the core of the parent galaxy. It can do
this because it contains a central supermassive object,
which attracts stars like a honey pot attracts bees.
> You said above that galaxies are sparsely populated but
> globular clusters are comparatively dense with stars and their
> "compactness" is enough to hold them together without supermassive objects
> in their cores.
Not indefinitely. Not at all when the cluster has to pass
through the relatively dense field of stars in the vicinity
of a galactic centre. Even if they didn't fall completely
apart at the first pass, they would lose their compactness.
The second pass would be the last.
Galaxies are sparsely populated, but still they contain
hundreds of millions of stars, and a star does not have
to actually collide with another star in order to interact
with it gravitationally. And globular clusters may be
dense when compared to our vicinity, but they still
manage to do a pretty good impersonation of a vacuum.
A loose globular association of stars passing through a
galaxy unscathed is like a small smoke ring passing through
a hurricane, or a bubble passing through a mass of foam.
A supermassive object performing the same trick is like a
bullet passing through a mass of foam, or through a cloud.
> http://antwrp.gsfc.nasa.gov/apod/ap990225.html <-This APOD talks about
> the dissolving globular cluster ngc6712.
And I think it illustrates my point nicely.
Even if a spherical arrangement of stars without
a central attractor could persist without periodic
replenishment, how could it form in the first place?
If a lot of separate stars all fall together to form
a cluster, their total kinetic energy is sufficient to
allow them to fall apart again.
..
MOA Observer
The image of a star the light of which has passed close to the sun will be
distorted only the distortions are too small to see. If we were able to
resolve the disc of a star as it was lensed by the sun we would see that
the image had been stretched into an arc.
When stars are microlensed by point sources within our galaxy (a lens star
or star system) the deflections are small because the einstein radius of
the lens is small relative to our distance from it. Even though we can't
see the various distortions in the image of the source star they are still
present. With a telescope able to resolve tiny fractions of arcseconds we
would see einstein crosses, rings, and arcs (the full range distortion
effects) on the light from a source which has been microlensed.
It is because the gravitational field of galaxy clusters is large compared
to their distance from us that we see arcs.
Paul
MOA Observer
You may very well be correct about there being a significant amount of dark
matter in the universe however if I am correct that there is a problem with
gravitational theory (gravitational force works as a higher degree polynomial
is currently my favourite guess :) it shouldn't make much difference to your
theory as it will still mean that there will be an increased amount of
gravitational lensing. Infact a small R^6 term or R^8 term may be beneficial to
your theory I don't know.
If dark matter is a bunch of dust and gas then we would see it because it would
have to make up a huge proportion of the matter in the milky way disc to
account for the rotation curves of the galaxy and it would have to be fairly
evenly distributed we would see it as absorption lines of stars. The column
densities of matter in our galaxy obtained from the spectra of stars in our
galaxy and nearby galaxies don't support the theory of huge amounts of dust and
gas.
Globular clusters may have super massive cores but the only candidate for this
so far is I think M15.
There are many globular clusters in the LMC maybe more than in the milky way
and some of them have formed fairly recently
http://antwrp.gsfc.nasa.gov/apod/ap010311.html . I don't understand the
process of their formation but here are some parameters I can think of off the
top of my head. A gas cloud which is fairly isolated, of uniform density,
contracting fairly fast. Then star formation should occur throughout the cloud
quickly and uniformly. I see no reason why the stars in the region shouldn't
become gravitationally bound.
This indicates to me that there is a significant loss of globular clusters as a
galaxy ages.
There have been x-ray sources found in globular clusters but they are found in
binary systems (i.e. small black holes with a companion). If there is a super
massive black hole in the core of a globular cluster then the dense region of
stars in the core (one hundred stars per cubic parsec) should provide a huge
x-ray source in the centre as the stars whose orbits are perturbed by the
passage through the milky way come into close contact with the core. As the
star density in globular cluster cores is similar to that of the bulge there
should be a similar sized x-ray source.
Martin Gradwell
Jonathan Silverlight <jsi...@merseia.fsnet.co.uk> wrote in message
news:JVTimjWu...@jsilver.freeserve.co.uk...
> In message <aj3ckn$ism$1...@newsg3.svr.pol.co.uk>, Martin Gradwell
> <mtgra...@btinternet.com> writes
> >
> >George Dishman <geo...@briar.demon.co.uk> wrote in message
> >news:1028660991.23496....@news.demon.co.uk...
>
> snip
>
> >>
> >> ... and the speed of light is infinite.
> >
> >In other words, it doesn't really reduce to Newtonian
> >physics in any circumstances. Newton knew that the
> >speed of light was not infinite.
>
> Did he actually know that when he was doing the work? It was only
> discovered in 1675. That must have been an extraordinary revolution in
> thinking, BTW.
Principia, Book 1, Proposition 96. Theorem 50 Scholium:
"For it is now certain from the phenomena of Jupiter's satellites,
confirmed by the observations of different astronomers, that
light is propagated in succession, and requires about seven
or eight minutes to travel from the sun to the earth".
.. "Therefore because of the analogy there is between the
propagation of the rays of light and the motion of bodies,
I thought it not amiss to add the following propositions for
optical uses; not at all considering the nature of the rays of
light, or enquiring whether they are bodies or not; but only
determining the curves of bodies which are extremely like
the curves of the rays."
Book 3 Proposition 6. Theorem 6.
"That *all* bodies gravitate towards every planet"
(my emphasis).
Optics, book II, part 3, proposition 11:
"Light is propagated from luminous bodies in time,
and spends about seven or eight minutes of an hour
in passing from the Sun to the Earth".
Book 3, part 1, query 1:
"Do not bodies act upon light at a distance, and by their
action bend its rays; and is not this action (caeteris paribus)
strongest at the least distance?"
Book 3 Part 1 Query 29:
"Are not the rays of light very small bodies emitted
from shining susbstances?"
Principia (according to Britannica Great Books) was
written over seventeen or eighteen months during 1685
and 1686, and published by Halley in 1687. However,
Newton originally began to work on a theory of gravity,
studying the orbit of the moon, in 1666.
Optics, first published 1704, was compiled from papers
delivered to the Royal society between 1672 and 1676,
according to the biographical note in Britannica Great Books.
However, according to its preface, part of Optics was
written in 1675, and the rest was added about twelve years
later, "except for the third book, and the last proposition of
the second, which were since put together out of scattered
sources".
I don't think Newton would have been greatly surprised
by the discovery of the finite speed of light. Despite his
disclaimer about not considering the nature of the rays
of light, it seems very likely to me that he thought of light
as consisting of small bodies, "corpuscles", as described
in query 29. The queries in book 3 were described as
such, rather than as propositions, not because Newton
thought they might prove incorrect but because he lacked
strong evidence for them at the time of publication.
And he considered the laws of gravitation to apply to
all bodies.
> >> Nope, you said above where "gravity is not too strong".
> >> It is a poorer approximation closer to objects. Remember
> >> it shows up more in the orbit of Mercury than any other
> >> planet.
> >
> >43 seconds of arc in one century. And that's displacement
> >of the *perihelion*, not displacement of the planet. The
> >planet needn't be more than 170 metres away from its
> >predicted position, after a century of observation.
> >
> >This anomalous precession was apparently detected in
> >the 19th century, when good telescopes hadn't been
> >around for much more than a century, the best clocks
> >had a spring and a key to wind them up, there was
> >no photographic astronomy, all telescopes were
> >optical, and the best of them made Mercury look
> >like a vague blob.
>
> Are you saying it may be a mistake? I think you'll find it's been
> confirmed with modern measurements, and extended to the other planets.
> And ISTR that it's been observed in pulsar systems where the precession
> is measured in degrees per year.
The thing about pulsar systems is that we can't look at
them in close-up and determine the exact nature of the
systems, like we can with the solar system. We can't
know the sizes and positions of any planets involved.
We can't measure the oblateness of the stars. All we
can do is make inferences based on a very partial
understanding.
With regard to Mercury's perihelion:
Most people seem to be of the opinion that because
the perihelion is displaced 43 arcseconds, which is about
12,000 km, therefore the actual planet must be displaced
by that amount (nearly three planetary diameters) after
a century. Not so. After a century, when Mercury is
supposed to be at perihelion, it will actually be 12,000
km away from perihelion but just 170 metres away from
the position where it was predicted that it would be.
This displacement is
a) practically impossible to measure without miraculous
technology, of the sort that I doubt we can possess even
today, and
b) small enough to be potentially explicable using
all sorts of phenomena not related to GR. Solar wind,
radiation pressure, possible oblateness of the solar
core, all have effects that are at least in the right ball
park.
I once did a calculation of the effect of solar wind
which seemed to show that it was more than enough
to cause the anomalous precession. Unfortunately
when I repeated it I found that I'd made a mistake,
but at least my corrected figure was in the right ball
park. It is conceivable that solar wind is responsible
for the anomalous precession, if the solar wind is
just a few times stronger than I assumed it to be.
The displacements of other planets are even
smaller, because their orbits are more nearly
circular.
Oriel36
You are over the place here which is fine when you are organising a
particular view.If you accept that acceleration towards the great
attractor is actually occuring you will also have to except that
accelerating expansion is also occuring for you can't shift the view
from acceleration being one thing towards the great atrtractor and
acceleration being another with the galaxies flying apart.There is
only one common denominator that will satisfy apparent acceleration
for both and that is a translation of 'apparent acceleration' in
rotation.
Relativity gets it backwards,acceleration is relative ,rotation is
absolute.
George Dishman
"Jeff Root" <je...@freemars.org> wrote in message
news:f0b30c00.02081...@posting.google.com...
> George Dishman replied to Martin Gradwell:
>
> >> Light is affected by gravitation in the same way
> >> that material objects are. Newton knew it. Einstein
> >> showed it with his elevator gedanken. And yet,
> >> light does loop-the-loops, or spirals, or unstable
> >> circles, or hyperbolas, or, it seems, *anything*
> >> except ellipses.
> >
> > AFAIK in simple topology, away from a BH, the paths
> > are virtually straight in the conventional sense. The
> > most extreme effects I have seen are the Einstein cross
> > and the arcs typical of the Abell 2218 photo you cited.
> > What is possible in theory is another matter.
>
> I suspect that his comment was prompted by my black hole
> animation at http://www.freemars.org/jeff2/BH3.htm which
> shows light doing all the strange things he says it does.
> This animation was based partly on textbook illustrations
> and partly on my general knowledge of light, gravity, and
> black holes, but the light path was not calculated, just
> guessed at, so it may be way off. I would bet that it's
> pretty close, but *that* doesn't prove anything. :-)
It's a neat diagram and I would love to see one calculated
properly, but as you say if it is just based on assumption,
it doesn't really prove anything, but I still think it is
great for conveying the argument.
> The one thing I would repeat to Martin, that you first said
> and Joseph Lazio amplified, is that light is expected to bend
> this way only when within a few kilometers of a stellar-size
> black hole, and hardly bends at all when it is a few thousand
> kilometers away. As long as the observational evidence
> continues to be that the speed of light in vacuum is constant,
> light cannot travel in an elliptical path.
>
> Please address his argument about it being impossible to
> measure changes in the speed of light, now that the speed of
> light is used to define the standard of length. You are so
> good at clearing up this kind of confusion. Although it is
> the sort of argument that I have come to expect from Aladar,
> JosX, Robert Winn, or Oriel36, in Martin's case I can hope
> that he will follow and understand the explanation.
I didn't really take that comment as serious. Martin is
not like those you mention and knows far too much to be
fooled by that old chesnut, as I suspect do you ;-)
The Michelson-Morley experiment compared the speed of
light in different directions by looking for a fringe
shift. They found no shift implying the speed was
anisotropic. Would changing the definitions for speed
or distance change whether or not the fringes shifted?
> > Well remember that you get the same radius for a black
> > hole from Newton by calculating an escape velocity equal
> > to the speed of light. That means any photon that doesn't
> > hit the event horizon is on a hyperbolic path in Newtonian
> > physics, so how did you predict an elliptical path for a
> > photon over inter-galactic distances using Newton?
>
> One thing that my animation clearly shows is that the photon
> sphere is at least as interesting as the final event horizon.
> Any photon which hits the photon sphere falls in. A photon
> at the photon sphere can avoid falling in only by being in an
> upward or precisely horizontal trajectory, which is impossible
> for a photon coming from outside that sphere. Any photon
> *inside* the photon sphere must be in an upward trajectory to
> escape. A photon just above the final event horizon must be
> headed straight up to escape.
>
> As the animation shows, even a beam of light aimed a bit to
> the side of the photon sphere is doomed.
Exactly, there is no half-way measure. Either it goes in
or it is on a hyperbolic trajectory (in Newton at least).
Martin Gradwell
>
> "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> news:aj3ckn$ism$1...@newsg3.svr.pol.co.uk...
> > Present lengthening of light paths is observed,
> > except in the vicinity of the observer. In a non
> > -Euclidean geometry (such as we get when we
> > assume that elliptical orbits are maximally straight
> > paths in a curved manifold) this does not have to
> > imply that the volume of space is increasing.
>
> However, there is no observational evidence for that
> amount of bending, and AFAIK eliptical orbits are not
> possible in GR. Hence "Present lengthening of light
> paths is observed," is taken as expansion.
I am now strongly of the opinion that there is
observational evidence for that amount of light
bending.
Geodesics in GR are maximally straight. That at first
glance seems incompatible with the notion of circular
or hyperbolic orbits, not just elliptical ones.
The GR explanation of such orbits is that they aren't
_really_ hyperbolic or elliptical, but the curvature of
the underlying spacetime gives them the appearance
of being so. This explanation applies not only to
planetary and cometary orbits, but also to the null
geodesics followed by light grazing the edge of
the sun.
So, elliptical orbits are not possible in GR, and
neither are hyperbolic or circular orbits. But, there
are orbits that _look_ so much like hyperbolic or
circular or elliptical orbits that scientists feel justified
in taking the liberty of depicting them as such.
Without taking such a liberty it is impossible to
convey any intuitive notion of what is going on.
A closed universe is often depicted using a balloon
analogy. The Geodesics on a spherical balloon are
great circles. Because of this, it seems reasonable to
depict them as circles, even though their curvature is
in a direction which cannot be directly experienced
by "flatlanders" embedded in the balloon surface,
who will experience them as straight lines that
mysteriously wrap around..
These geodesics can also be depicted as ellipses,
though. If you look at a picture in a book of a
terrestrial globe, the lines of longitude will appear
to follow elliptical paths.
It can be argued that a depiction of null geodesics
as ellipses would be misleading, because the ellipses
have non-uniform curvature, and a great circle is
really uniformly curved throughout its length. This
would be a good argument against using ellipses
in a representation of a homogeneous universe,
because in such a universe the geodesics really have
constant curvature throughout their length. However,
I think it makes perfect sense to use ellipses in
the depiction of a highly nonhomogeneous universe.
If you haven't ever seen elliptical depictions of
null geodesics, perhaps it is because nobody has
ever tried to depict such a universe.
...
> > > For an elliptical orbit there is strong bending near
> > > the mass but also at the other end of the ellipse. That
> > > is entirely contrary to GR and in fact any theory of
> > > gravity that I know of.
> >
> > Ever hear of a man named Isaac Newton?
> > Not a lot of people know it, but he had a theory
> > of gravitation. :-)
>
> Yep, shame it doesn't work :-(
Up until 1915, the predictions of Newtonian theory
were essentially identical to the predictions of Einstein's
developing gravitational theory, that became GR.
I can actually see the utility of having two different
ways of looking at the world, that don't necessarily
reflect physical differences. The glass is half full/
the glass is half empty. What is the testable difference
between these two points of view? But there are
people who are so conservative that they won't
abandon an old theory for a new one unless there
is a testable difference between the two. So, as
soon as he realised that Newton's theory predicted
light bending, Einstein was obliged to come up with
some other testable difference between his theory
and Newton's. Did he really succeed?
The world thought so in 1919. Really, though,
the eclipse photographs and perihelion observations
were far from conclusive. Eddington's enthusiastic
endorsement was what carried the day, not any
conclusive scientific evidence. Of couse the situation
is different now. It always is.
>
..
[re: inhomogeneous cosmologies]
> Check Peebles "Principles of Physical Cosmology".
> He devotes severl pages to it, shows relevant plates
> and mentions a number of the large scale structures
> you have discussed.
I'll check it out. I've done a quick web search
already and seen one critical review of it.
http://home.att.net/~agorgun/CP-08.htm
- would you say that this is a fair criticism?
..
> > until 1915 the amount of bending predicted by Newton's
> > theory was exactly the same as the amount predicted
> > by Einstein. Which must mean that relativity, pre-1915
> > vintage, allowed light to follow elliptical paths (though
> > it would have described then as maximally straight paths
> > in a curved spacetime, I don't see how the predictions
> > could have differed in any essential way from those
> > of Newtonian physics).
>
> Well remember that you get the same radius for a black
> hole from Newton by calculating an escape velocity equal
> to the speed of light. That means any photon that doesn't
> hit the event horizon is on a hyperbolic path in Newtonian
> physics, so how did you predict an elliptical path for a
> photon over inter-galactic distances using Newton?
My simulations could be interpreted as simulations
of the interior of the Newtonian equivalent of a black
hole. Photons that move outward from the centre always
fall back again, eventually. The photons which get
furthest away before falling back are those that follow
a degenerate straight out/straight back orbit. Except
for these degenerate orbits, all the others are elliptical
with minor perturbations. There are no truly hyperbolic
orbits in this model. There would be if there were
things that could fall in from the outside, or that could
attain speeds faster than light in some other way, but
these things don't happen.
You've already seen how lots of elliptical paths
can converge at one location if you've looked at
http://www.btinternet.com/~mtgradwell/univ-ray.jpg
If you want to see yet more ellipses, take a look at
http://www.btinternet.com/~mtgradwell/ellipses2.jpg
which is new. The attactor is at the top. This is
basically the ellipses.jpg which I used to illustrate
how paths can lengthen, but with a few more
and longer paths, and no manual amendments.
The point is all of these diagrams are constructed
using Newtonian rules, so that all of the elliptical
paths in them are paths that could be followed by
light in a highly inhomogeneous Newtonian closed
universe.
..
Martin Gradwell
>
> >> Light is affected by gravitation in the same way
> >> that material objects are. Newton knew it. Einstein
> >> showed it with his elevator gedanken. And yet,
> >> light does loop-the-loops, or spirals, or unstable
> >> circles, or hyperbolas, or, it seems, *anything*
> >> except ellipses.
> >
> > AFAIK in simple topology, away from a BH, the paths
> > are virtually straight in the conventional sense. The
> > most extreme effects I have seen are the Einstein cross
> > and the arcs typical of the Abell 2218 photo you cited.
> > What is possible in theory is another matter.
>
> I suspect that his comment was prompted by my black hole
> animation at http://www.freemars.org/jeff2/BH3.htm which
> shows light doing all the strange things he says it does.
Yes, I did look at your site before making the comment.
But I was also thinking of the diagrams in Chandrasekhar's
"The Mathematical Theory of Black Holes", which I
suspect were your source of inspiration. His diagrams
for the Schwarzschild metric are similar to your animated
diagram. Those for Kerr space-time are even stranger.
..
> The one thing I would repeat to Martin, that you first said
> and Joseph Lazio amplified, is that light is expected to bend
> this way only when within a few kilometers of a stellar-size
> black hole, and hardly bends at all when it is a few thousand
> kilometers away.
A stellar mass black hole, if such a thing exists, will have
the same gravitational effect on distant light as the sun does.
That's not what I'm talking about, though. I'm talking about
an object which is as massive as thousands of galaxies
put together, and which is surrounded by many thousands
or even millions of galaxies, each of which can contain a
hundred million stars or more. Other people think of this
sort of thing as a small structure, but not me.
> As long as the observational evidence
> continues to be that the speed of light in vacuum is constant,
> light cannot travel in an elliptical path.
Take a look at the threads
"Speed of light has changed, claims Macquarie physicist (Forwarded)"
and
"SPEED OF LIGHT SLOWING DOWN"
>
> Please address his argument about it being impossible to
> measure changes in the speed of light, now that the speed of
> light is used to define the standard of length.
I think the best argument here would be that it is
so obvious that the speed of light changes from place
to place or from time to time, the official denial of it
that is enshrined in the standard definitions is clearly
a denial of reality. Reality can't be denied indefinitely.
Eventually, something is bound to give. It might take
a few centuries, though.
..
> One thing that my animation clearly shows is that the photon
> sphere is at least as interesting as the final event horizon.
> Any photon which hits the photon sphere falls in. A photon
> at the photon sphere can avoid falling in only by being in an
> upward or precisely horizontal trajectory, which is impossible
> for a photon coming from outside that sphere. Any photon
> *inside* the photon sphere must be in an upward trajectory to
> escape. A photon just above the final event horizon must be
> headed straight up to escape.
> As the animation shows, even a beam of light aimed a bit to
> the side of the photon sphere is doomed.
Consider how different this is from Newtonian Gravity,
where something falling in is bound to *escape*, if it doesn't
hit a hard surface.
Now, if only there was some way for infalling objects
or photons to become outfalling objects or photons.
Such as arriving at and passing periastron, perhaps.
But that can only happen outside the photon sphere,
apparently, unlike in Newtonian physics.
Mike Varney
<SNIP>
Site submitted to crank.net and dev null.
Martin Gradwell
..
> I agree that we are being drawn in. But the evidence
> does not suggest that we are being drawn in (in the
> sense of getting closer to the attractor), unless it is
> properly interpreted. We do not see blueshifted galaxies
> in the vicinity of the attractor. If you have read anything
> that suggests otherwise, I'd really appreciate a reference.
> The usual notion is that the blueshift indicates that we are
That should have been redshift, of course.
Martin Gradwell
Mike Varney <var...@collorado.edu> wrote in message
news:ajb6at$sqb$1...@peabody.colorado.edu...
Thanks, but it's been listed in crank.net since July 19 2000.
See http://www.crank.net/cosmology.html
I don't think dev null has quite the same pulling power
as crank.net, but I suppose I could be wrong.
If you want to make youself useful, please consider
lobbying crank.net to make my site "crank o' the day".
I doubt that they will, though. It isn't cranky enough,
and it isn't updated often enough.
I've just added a site meter to the site (but without making
any other alterations for the time being), so I hope you
will be able to get it some more publicity. I wuld be happy
to see at first hand the effect on traffic of a special mention
in dev.null.org, or wherever.
I personally like Dan Piponi's "Not the Crackpot Files"
http://homepage.mac.com/sigfpe/Physics/pots.html
It doesn't say much about each site, but it lists some
interesting sites.
G=EMC^2 Glazier
we are very near sighted. We need very thick glasses to see our nose.Our
nose came to be some 16 billion LY out. Some will say 14 billion others
will say 18 billion.The reason is not all noses are the same size. Bert
Mike Varney
>
> Mike Varney <var...@collorado.edu> wrote in message
> news:ajb6at$sqb$1...@peabody.colorado.edu...
> >
> > "Martin Gradwell" <mtgra...@btinternet.com> wrote in message
> > news:ajb55l$hi5$1...@newsg4.svr.pol.co.uk...
> > <SNIP>
> > > Martin Gradwell, mtgra...@btinternet.com
> > > http://www.btinternet.com/~mtgradwell/
> >
> > Site submitted to crank.net and dev null.
>
> Thanks, but it's been listed in crank.net since July 19 2000.
> See http://www.crank.net/cosmology.html
So, you are stupid and proud of it.
George Dishman
I looked but I misunderstood your point. The second diagram
makes it clearer. Yes, I agree, that is interesting. I will
have to have a closer look at that. Thanks for pointing it
out. I don't see it as strong anthropic though, there is no
necessity that we be in the centre of a structure in order
to exist. It is intriguing though.
> > > If, as I assume, light can follow elliptical paths just like those
> > > of a comet around a star, and if those paths are assumed to
> > > be maximally straight paths in a curved spacetime, the resulting
> > > topology is extremely non-trivial.
> >
> > On the other hand, I think the idea that light can follow
> > closed elliptical paths in GR is nonsense and contrary to
> > the observational evidence that supports GR. I think you
> > ignore this test to protect your idea and that is
> > unscientific.
>
> I've seen diagrams depicting light paths in the vicinity
> of a black hole, and in grazing passage close to the sun,
> or close to a galaxy acting as a gravitational lens. They
> tend to be hyperbolae except when they pass *very*
> close to a black hole, in which case we get these strange
> spirals and things.
Exactly, and the light near us is far from the GA, hence
a reasonable approximation would be a Newtonian hyperbolic
orbit.
>But, what is the shape of the path of
> light which circumnavigates a closed universe?
>
> In the case of a homogeneous universe, which
> is the only cosmology ever considered nowadays,
> the question is practically meaningless. A light
> beam follows a maximally straight path which cannot
> deviate to left or right, or up or down, because there
> are no concentrations of mass that might cause that
> to happen. Nevertheless it wraps round somehow,
> so that an observer can "see the back of his head".
> This situation is not properly depictable unless you
> have some sheets of five-dimensional paper to draw
> it on.
I won't try it with ASCII then ;-)
> We can suppress a few dimensions and get the
> famous balloon with pennies stuck on it analogy,
> and with the balloon being spherical the maximally
> straight paths on it are great circles which are, well,
> circular. But the insights gained from studying a
> balloon don't necessarily all transfer up to a higher
> number of dimensions.
No, it is _very_ limited. The two dimensional
infinitely thin theoretical surface represents the
four dimensional universe. You can only take that
so far before it becomes very misleading. Galaxies
can be depicted as penies stuck on with grease, or
as dimples on an orange.
> Remember that it isn't just the null geodesics
> followed by light that are said to be maximally
> straight in GR. So, too, are the paths of any
> freely falling test objects, and these can look
> remarkably elliptical to the untrained eye.
Remember in GR that is not a closed path but an
elongated helix in spacetime.
> Remember, too, that Lorentz transformation
> means that a circular orbit around a stationary
> centre can look like an elliptical orbit around
> a rectilinearly moving centre, and vice-versa.
Yep.
> What would be the shape of a closed orbit in a
> very inhomogeneous universe,
Even in a universe with a distribution of galactic
structures that is homogenous at large scale, any
individual photon path would be a random walk. An
inhomogenous universe would only affect the
statistics.
>with much of the
> mass concentrated in one place, according to GR?
On orange with one very big dimple?
> Is there any reason why it cannot be depicted as
> elliptical, perhaps with some anomalous precession?
> If not, why not? By elliptical, I mean having the
> appearance of a flattened spiral in a spacetime
> diagram, so that the projection of the orbit onto a
> spacelike slice of the universe would be an ellipse.
> The spacelike slice can be depicted as flat even
> if GR says it isn't "really" flat, in much the same
> way as the earth can be depicted as flat in a
> Mercator's projection or polar projection map.
I'll talk of ellipses elsewhere, there are too
many branches in this thread.
George Dishman
>
> George Dishman <geo...@briar.demon.co.uk> wrote in message
> news:1029007584.15035....@news.demon.co.uk...
> >
> analogy. The Geodesics on a spherical balloon are
> great circles. Because of this, it seems reasonable to
> depict them as circles, even though their curvature is
> in a direction which cannot be directly experienced
> by "flatlanders" embedded in the balloon surface,
> who will experience them as straight lines that
> mysteriously wrap around..
It is also misleading since there is no embedding
space in GR. That is one of the problems with
the balloon analogy.
Martin I'm going to have to cut a lot of this. I don't
have the time to go into the details of your arguments
and it wouldn't get us closer to a resolution if I did.
I doubt you are getting much from it now either, but
you could consider the key points that cause me to
reject your model so far. I'll summarise them at the
bottom.
> [re: inhomogeneous cosmologies]
> > Check Peebles "Principles of Physical Cosmology".
> > He devotes severl pages to it, shows relevant plates
> > and mentions a number of the large scale structures
> > you have discussed.
>
> I'll check it out. I've done a quick web search
> already and seen one critical review of it.
> http://home.att.net/~agorgun/CP-08.htm
> - would you say that this is a fair criticism?
No, if your read the first few equations carefully it
assumes that the scale on which homogeneity appears
is similar to the size of the universe. That is far
from the current model, though perhaps closer to
yours.
He also misses one of the main points of the book, it
is a summary of the then current state with lots of
useful pointers to standard observations. I find it a
great starting point, even if it is rather old.
> > Well remember that you get the same radius for a black
> > hole from Newton by calculating an escape velocity equal
> > to the speed of light. That means any photon that doesn't
> > hit the event horizon is on a hyperbolic path in Newtonian
> > physics, so how did you predict an elliptical path for a
> > photon over inter-galactic distances using Newton?
>
> My simulations could be interpreted as simulations
> of the interior of the Newtonian equivalent of a black
> hole.
Well if we are inside the event horizon of the Great
Attractor, the mass estimates are _seriously_ wrong!
Besides, as I said at the EH the escape velocity is c
so if we are inside, we should be moving towards it at
faster than the speed of light.
If we are outside, the orbits should be hyperbolae so I
do not believe there is any credible case for assuming
elliptical orbits for photons this far from the mass.
>Photons that move outward from the centre always
> fall back again, eventually. The photons which get
> furthest away before falling back are those that follow
> a degenerate straight out/straight back orbit. Except
> for these degenerate orbits, all the others are elliptical
> with minor perturbations. There are no truly hyperbolic
> orbits in this model. There would be if there were
> things that could fall in from the outside, or that could
> attain speeds faster than light in some other way, but
> these things don't happen.
>
> You've already seen how lots of elliptical paths
> can converge at one location if you've looked at
> http://www.btinternet.com/~mtgradwell/univ-ray.jpg
>
> If you want to see yet more ellipses, take a look at
> http://www.btinternet.com/~mtgradwell/ellipses2.jpg
> which is new. The attactor is at the top. This is
> basically the ellipses.jpg which I used to illustrate
> how paths can lengthen, but with a few more
> and longer paths, and no manual amendments.
>
> The point is all of these diagrams are constructed
> using Newtonian rules,
No, that is my point. The EH for the GA does not
include us, and Newtonian rules say the paths
should be hyperbolae, not ellipses.
In addition, you are assuming the speed of the
photons is reduced by the time they reach us. Try
this diagram, not to scale:
* galaxy
|
| _____---------------______
| / \
v v \
<-Earth GA |
Sun
It shows half an elliptical orbit for a very red
shifted source passing near the GA, and a local
galaxy whose light is not greatly affected.
Presumably you model says the light from close
to the GA is travelling at a speed different to
that of the light of the local galaxy, or the
light from the GA must have passed it at enormous
speed to still be moving at c near us. In fact it
would be a remarkable coincidence if all the light
from all directions arrived at c having left its
source at a variety of speeds. That is what I call
geocentric!
The light we see suffers aberration due to the
motion of the Earth around the sun and the change
of angle between the case shown and six months
later depends on the ratio of the speed of the light
to that of the Earth in orbit. So assuming the speed
of the light is different for the two sources, we
should see different aberration angles. I do not
believe we do, so I see evidence that the speed
of light for close and distant sources is the same.
>so that all of the elliptical
> paths in them are paths that could be followed by
> light in a highly inhomogeneous Newtonian closed
> universe.
I doubt a Newtonian universe can be closed since
Newtonian space had no concept of curvature.
If you want to try to convince me there is some
mileage in what you say try to come up with a
distribution of galactic structures such as
perhaps something analogous to a globular cluster
where we are near the rim. The GA might be like
the core. Then try to use the average mass to
show that bending could create an apparently
homogenous universe even though we should see
most galaxies in one hemisphere. You need to
use hyperbolic photon paths though.
I don't know if it can be done, and I doubt it,
but it would be a more logical extension of the
Newtonian model if that is what you want to do.