WIMPs AWOL Again?
Robert L. Oldershaw
dwarf galaxies may "exculde generic WIMP candidates with mass less
than 27 GeV..." .
Reference: http://arxiv.org/abs/1108.2914
Time to re-evaluate the conventional WIMP hypothesis?
Time to think about those hundreds of billions of unbound planetary-
mass objects indicated by the microlensing observations of Sumi et al?
See: http://arxiv.org/abs/1105.3544 .
Time to give a fair hearing to M.R.S. Hawkins' excellent discussion
"The case for primordial black holes as dark matter"? See:
http://arxiv.org/abs/1106.3875 .
Time to think about what might be generating the huge ARCADE-2 excess
in the radio background?
eric gisse
26964-13...@hydra.herts.ac.uk:
> Analyses of Fermi gamma-ray observations of eight Milky Way Galaxy
> dwarf galaxies may "exculde generic WIMP candidates with mass less
> than 27 GeV..." .
>
> Reference: http://arxiv.org/abs/1108.2914
>
> Time to re-evaluate the conventional WIMP hypothesis?
One theory among several - one down, infinity minus one to go.
>
> Time to think about those hundreds of billions of unbound planetary-
> mass objects indicated by the microlensing observations of Sumi et al?
> See: http://arxiv.org/abs/1105.3544 .
Sure, for a moment.
Let's take the number of objects at face value and disregard the author-
admitted (one that you have opined about as well) possibility this may
have just been a region with more than usual. Integrate the entire pile
across the volume of the galaxy, and you get something just south of 5%
of what constitutes the dark matter mass budget for this galaxy.
Just a little bit short.
>
> Time to give a fair hearing to M.R.S. Hawkins' excellent discussion
> "The case for primordial black holes as dark matter"? See:
> http://arxiv.org/abs/1106.3875 .
Ah, M.R.S. Hawkins. Well, I guess its' nice that at least you aren't
citing his repeatedly-debunked claims regarding quasar variability.
Let us consider this key phrase:
"The most serious objection to dark matter in the form of compact
bodies has come from observations of microlensing of stars in the
Magellanic Clouds."
Let's look back at the SuperMACHO survey, one that was a survey of the
LMC specifically meant to look for such objects. No such populations.
Now replace SuperMACHO with "OGLE I", "OGLE II", and "OGLE III". The
only thing that changes is that there *are* enough observed events to be
largely consistent with the findings of Sumi, et. al.
However, the oft-claimed huge populations of dark matter tied up in
massive compacts are yet to be found. Without as much as a sniff from
you, I might add.
>
> Time to think about what might be generating the huge ARCADE-2 excess
> in the radio background?
Stranger than expected interplanetary medium?
I can never get too worked up about the galaxy, on the whole, glowing a
little more than expected in the radio because 'expected' is fully a
function of our current best guess model of stellar populations, the
interplanetary medium, presence of other structures like nebulae, etc.
How, if at all, this ties into dark matter is speculative at best.
>
> RLO
> http://www3.amherst.edu/~rloldershaw
>
Robert L. Oldershaw
> "Robert L. Oldershaw" <rlolders...@amherst.edu> wrote in news:mt2.0-
> 26964-1313491...@hydra.herts.ac.uk:
>
>
> One theory among several - one down, infinity minus one to go.
>
This my main worry. Currently fashionable theoretical speculations
like string/brane notions, supersymmetry, quintessence, WIMPs, and so
on, are so "adjustable" that they are effectively untestable in any
definitive manner.
If WIMPs are complete no-shows in the canonical mass range, then one
can merely posit that the WIMPs are more exotic than expected and have
a much larger mass. This dodge has been used in so many theoretical
physics contexts in recent decades that its radical departure from
proper scientific norms is hardly noticed anymore. But the fact is
that it makes these "scenarios" effectively incapable of being
falsified.
If one can arbitrarily change the predictions of a "scenario", and/or
tack on ad hoc adjustable parameters, then is this good science? Is it
science at all?
Phillip Helbig---undress to reply
Oldershaw" <rlold...@amherst.edu> writes:
> Analyses of Fermi gamma-ray observations of eight Milky Way Galaxy
> dwarf galaxies may "exculde generic WIMP candidates with mass less
> than 27 GeV..." .
They are weakly interacting MASSIVE particles---maybe more than 27 GeV.
For decades, neutrino masses kept being excluded from more and more mass
ranges, but today we know they have a mass.
> Time to re-evaluate the conventional WIMP hypothesis?
Why?
We don't know what dark matter is. That's why we look for it. When we
find it, we'll know. There might be more than one kind. That is real
science, i.e. when one doesn't know the result beforehand.
> Time to think about those hundreds of billions of unbound planetary-
> mass objects indicated by the microlensing observations of Sumi et al?
> See: http://arxiv.org/abs/1105.3544 .
Not in the context of dark matter, no. Yes, they might be dark matter,
but not an appreciable fraction of the dark matter.
> Time to give a fair hearing to M.R.S. Hawkins' excellent discussion
> "The case for primordial black holes as dark matter"? See:
> http://arxiv.org/abs/1106.3875 .
Hawkins's claim has been proved wrong in the refereed literature, and
no-one has contested this in the refereed literature. That's enough for
most people.
Robert L. Oldershaw
<hel...@astro.multiCLOTHESvax.de> wrote:
> In article <mt2.0-26964-1313491...@hydra.herts.ac.uk>, "Robert L.
>
>
> They are weakly interacting MASSIVE particles---maybe more than 27 GeV.
>
Or not?
Could you please tell us what that mass might be, or offer any sort of
predicted mass range by which the WIMP hypothesis might be
unambiguously falsified?
eric gisse
It depends on the theory, Robert.
You'll note that "weakly interacting massive particle" applies to a lot of
different things, including neutrinos. There's no particular theory here,
which is something people, including myself, have been trying to tell you.
Robert L. Oldershaw
> "Robert L. Oldershaw" <rlolders...@amherst.edu> wrote innews:mt2.0-14107...@hydra.herts.ac.uk:
>
> > Could you please tell us what that mass might be, or offer any sort of
> > predicted mass range by which the WIMP hypothesis might be
> > unambiguously falsified?
>
>
So, the bottom line is that you cannot make a definitive prediction
regarding the galactic dark matter.
You have a huge number of poorly constrained "theories" that offer you
a huge number of pseudo-predictions, any one of which can adopted or
explained away (if need be).
RLO
Discrete Scale Relativity
eric gisse
> On Aug 18, 3:33 am, eric gisse <jowr.pi.ons...@gmail.com> wrote:
>> "Robert L. Oldershaw" <rlolders...@amherst.edu> wrote
>> innews:mt2.0-14107...@hydra.herts.ac.uk:
>>
>> > Could you please tell us what that mass might be, or offer any sort
>> > of predicted mass range by which the WIMP hypothesis might be
>> > unambiguously falsified?
>>
>> It depends on the theory, Robert.
>>
> ----------------------------------------------------------------------
-
> ---------------------
>
> So, the bottom line is that you cannot make a definitive prediction
> regarding the galactic dark matter.
Plenty of _definitive_ predictions can be made in terms of interaction,
halo size, effects on lensing profiles, stellar orbits, etc. Why isn't
that good enough?
>
> You have a huge number of poorly constrained "theories" that offer you
> a huge number of pseudo-predictions, any one of which can adopted or
> explained away (if need be).
Well, that's how science works. Scientists make some theories, and as
more evidence comes in the bad ones are excluded.
I note you have a different level of increduility for your theory
(factor of 15 wide prediction of neutron star masses) versus other
theories.
>
> RLO
> Discrete Scale Relativity
Robert L. Oldershaw
> "Robert L. Oldershaw" <rlolders...@amherst.edu> wrote innews:mt2.0-18729...@hydra.herts.ac.uk:
>
> Well, that's how science works. Scientists make some theories, and as
> more evidence comes in the bad ones are excluded.
That's how things have been going for decades, except that nothing
actually gets excluded, just "adjusted". Strings, branes, WIMPs,
SUSY, extra dimensions, and so on, have been around for decades and
are "adjusted" in an ad hoc manner when observations or theoretical
constraints do not support them. Has anything been "exluded"?
Hardly! There are even super-optimists who hold out hope for magnetic
monopoles and proton decay after many, many falsifications. String
theory: 43 years and still not one definitive prediction!
The best science is science based on principles that can lead to
definitive predictions. See the development and evolution of
relativity theory for an archetypal example of this best science.
Even heuristic, model-building science is legitimate so long as it can
use its empirically-derived order, constraints and patterns to
generate definitive predictions.
But if a theory cannot make a definitive prediction then it is pure
speculation (to put it politely), and should be explicitly treated as
such by scientists and the media.
RLO
Fractal Cosmology
Phillip Helbig---undress to reply
Oldershaw" <rlold...@amherst.edu> writes:
> > They are weakly interacting MASSIVE particles---maybe more than 27 GeV.
> >
> ----------------------------------------------------------------------------------------
>
> Or not?
>
> Could you please tell us what that mass might be, or offer any sort of
> predicted mass range by which the WIMP hypothesis might be
> unambiguously falsified?
No, because my science is based on observation. What is the mass of the
Earth? No way to find out except to measure it. Same idea. Yes, it
might be conceivably possible for a theory to predict everything, but
one shouldn't criticise observations in the absence of such a theory.
Phillip Helbig---undress to reply
Oldershaw" <rlold...@amherst.edu> writes:
> > It depends on the theory, Robert.
> >
> --------------------------------------------------------------------------------------------
>
> So, the bottom line is that you cannot make a definitive prediction
> regarding the galactic dark matter.
The whole idea of science is that different theories make different
predictions which can be used to distinguish them. You seem to think
that having more than one theory is a bad idea (and thus don't see the
need for observations).
Christian Froeschlin
> That's how things have been going for decades, except that nothing
> actually gets excluded, just "adjusted". Strings, branes, WIMPs,
> SUSY, extra dimensions, and so on, have been around for decades and
> are "adjusted" in an ad hoc manner when observations or theoretical
> constraints do not support them. Has anything been "exluded"?
I have to say I'm no expert on these theories, but it seems to me that
adapting theories in light of new evidence is science, as long as there
is still room to do so within previously existing constraints. In that
case, there is not enough data to exclude the theory.
If future research were to reveal that the existance of WIMPS > 27 GeV
would necessarily cause some observable effect, and that effect is never
observed, then it would be possible to exclude the theory.
It is only holding on to unmodified theories by ignoring
inconvenient data that would be a problem.
Robert L. Oldershaw
<hel...@astro.multiCLOTHESvax.de> wrote:
> In article <mt2.0-18729-1313673...@hydra.herts.ac.uk>, "Robert L.> > --------------------------------------------------------------------------------------------
>
> > So, the bottom line is that you cannot make a definitive prediction
> > regarding the galactic dark matter.
>
> The whole idea of science is that different theories make different
> predictions which can be used to distinguish them. You seem to think
> that having more than one theory is a bad idea (and thus don't see the
> need for observations).
Your two posts are somewhat contradictory.
If any theory that claims to be about "fundamental" understanding in
cosmology and/or physics and it cannot predict the fairly specific
nature of what the overwhelming majority of the Universe is composed
of, then I say that theory is mere arm-waving. If it provides no
definitive predictions, it is not science. It is still in a pseudo-
science stage of development.
RLO
Discrete Scale Relativity
[Mod. note: the weasel word here being 'definitive' -- mjh]
eric gisse
>
> If any theory that claims to be about "fundamental" understanding in
> cosmology and/or physics and it cannot predict the fairly specific
> nature of what the overwhelming majority of the Universe is composed
> of, then I say that theory is mere arm-waving. If it provides no
> definitive predictions, it is not science. It is still in a pseudo-
> science stage of development.
What, in your mind, constitutes a 'definitive' prediction?
The bulk properties of dark matter are pretty nailed down.
* Minimal or zero non-gravitational self interaction.
* Zero electromagnetic interaction.
* Most likely particulate in nature, due to massive observational exclusion
of MACHO theories.
* Nonrelativistic at decoupling, even more nonrelativistc now.
* The equation of state for dark matter is that of dust, which is highly
distinguishable between that of relativistic matter, photons, scalar and
higher spin fields, etc.
What further details are required of dark matter to explain cosmology
better? The problem for the last few years is that particle physics has no
answer.
Did you know that the tools used to describe modern cosmology (GR and its'
various solutions discovered over the years) all predate the standard
model? Knowledge of composition is not required here, which is something
you don't seem to grasp.
By the way, do you stand by your claim that a neutron star size that spans
a factor of 15 while extending into singularity territory is in any way
definitive? Or do you think the double standards are ok?
Robert L. Oldershaw
>
> I have to say I'm no expert on these theories, but it seems to me that
> adapting theories in light of new evidence is science, as long as there
> is still room to do so within previously existing constraints. In that
> case, there is not enough data to exclude the theory.
>
> If future research were to reveal that the existance of WIMPS > 27 GeV
> would necessarily cause some observable effect, and that effect is never
> observed, then it would be possible to exclude the theory.
>
> It is only holding on to unmodified theories by ignoring
> inconvenient data that would be a problem.
Let me put things in the most simple form.
Ideally we want theories that make definitive predictions that tell us
whether the theory is fundamentally right, or fundamentally wrong.
In the latter case, one does not "modify" the fundamentally wrong
theory. One seeks a new model based on a new theoretical principle.
We do not need epicycles. We need new and good ideas that lead to
definitive predictions.
RLO
Discrete Scale Relativity
Robert L. Oldershaw
>
> By the way, do you stand by your claim that a neutron star size that spans
> a factor of 15 while extending into singularity territory is in any way
> definitive? Or do you think the double standards are ok?
>
To answer your question, the radius range for neutron stars is exactly
the same as the radius range for subatomic nuclei, except that you
must multiply the nuclear radii by a factor of 5.2 x 10^-17. This is
a definitive prediction, regardless of how you want to misconstrue
that.
Robert L. Oldershaw
http://www3.amherst.edu/~rloldershaw
eric gisse
> whether the theory is fundamentally right, or fundamentally wrong.
>
> In the latter case, one does not "modify" the fundamentally wrong
> theory. One seeks a new model based on a new theoretical principle.
Like for example, if one theory predicts dark matter is made of solar
mass MACHOs but years of surveys only find some planets that make up a
few percentage points, I suppose you would consider that an example of a
theory that is fundamentally wrong.
[Mod. note: quoted text trimmed. Please try to trim quoted text so
that only directly relevant material is quoted -- mjh]
Phillip Helbig---undress to reply
Oldershaw" <rlold...@amherst.edu> writes:
> Ideally we want theories that make definitive predictions that tell us
> whether the theory is fundamentally right, or fundamentally wrong.
Agreed.
> In the latter case, one does not "modify" the fundamentally wrong
> theory. One seeks a new model based on a new theoretical principle.
This is a straw-man argument. Most theories are not theories of
everything which unanimously predict everything of interest. Most
theories have some parameters which (as far as we know now) must be
determined by observation. This does not mean that the theory is
fundamentally wrong. For example, many new species of animals and
plants are still being discovered. Our theories of biology are not
fundamentally wrong on the grounds that they were not all predicted. In
some cases, further progress on the theoretical side can allow one to
predict things which were not possible in an older, coarser version of
the theory. (While not as clear-cut, even postdictions are OK as long
as they are unique and not adjustable. It is often an accident whether
theory or observation is more advanced and accidents of human history
have no bearing on the underlying physical reality.)
I recommend John D. Barrow's book THEORIES OF EVERYTHING. It is about
what we won't know even if we had a theory of everything (as the term is
commonly used). Check it out.
> We do not need epicycles.
Epicycles are, of course, an example of adjusting a theory to meet
better observations, and rightly criticised for this. However, it is
important to keep two things in mind. First, epicycles make a testable
prediction, namely how the distance to a planet varies with time. The
angular motion can be fit exactly with a sufficient number of epicycles
(this is essentially Fourier synthesis (or analysis, depending one one's
point of view), but measuring the distance can distinguish epicycles
from other models. (To be sure, Copernicus's original heliocentric
model was LESS accurate regarding positions of the planets, but, even
disregarding the question of distance for the moment, in some sense more
accurate because it is closer to the truth. This is the (perhaps
undefinable) beauty of a theory which is often an indicator of what is
right.) Also, the main reason Ptolemy's epicycles stayed around for so
long is because the Church burned people who thought otherwise: not what
we today understand as scientific discourse.
Think of the so-called old quantum theory. It solved many problems in
classical physics, but was not definitive. What happened? Was it
replaced by a new paradigm? No, it was refined. Was there input from
observation? Sure---how else would one know that it was not correct.
Did this involve adjusting free parameters until they fit? No. It's
still not a complete theory in some sense, but it is better than the old
quantum theory. This is the way most science progresses. Kuhn's ideas
about overthrowing the paradigm, with the Copernican revolution (a pun
which many don't get) being an example, are mostly wrong since based on
examples like this when it was not debate within science but rather the
reduction of torture which allowed a new paradigm to arrive. (Also,
Kuhn's ideas contain the seeds of their own distruction. Either they
are scientific or not. If not, then we can ignore them. If they are,
then by his own reasoning they will soon be replaced with a new
paradigm.)
> We need new and good ideas that lead to
> definitive predictions.
Right. And when these definitive predictions are falsified by other
observations, one has to move on. The steady-state theory was, in
almost all respects, a very good theory. It made testable predictions.
They were falsified. Some people, like Bondi and Morison, moved on.
Others, like Hoyle (who had done very good work in other areas), started
to ignore reality.
eric gisse
How do you know that neutron stars fit inside such a range? You've been
arguing for the past few days that science has ABSOLUTELY NO IDEA!!! how
big a neutron star is.
A proton (Hydrogen) is about 0.8 fm, and Uranium is [1] roughly 175,000
fm. So taking 10km as the middle of the neutron star range gives a rough
upper limit of...two million kilometers? Using *your* "predicted" (when
are you going to show how you obtained that prediction?) 6km gives an
upper bound of about 1.8 million km. That's not even taking into account
that random factor that you pulled out of the air.
As for your claim that the range is the same, you aren't even within the
correct order of magnitude. Factor of 15 vs factor of ~200,000. When
your definitive prediction is incorrect by four orders of magnitude, are
you going to add epicycles or just admit your theory is wrong?
I consider this more of a test of how well you will stick to your claims
regarding definitive predictions and the validity of a theory more than
anything else, because you aren't even close to being correct here.
By the way, I would like to know if you even LOOKED at the published
litearture regarding neutron star radii. Did you?
Robert L. Oldershaw
>
> Like for example, if one theory predicts dark matter is made of solar
> mass MACHOs but years of surveys only find some planets that make up a
> few percentage points, I suppose you would consider that an example of a
> theory that is fundamentally wrong.
Have you read Mike Hawkins' preprint: "The case for primordial black
holes as dark matter"?
I think that he would vigorously disagree with your statement above.
And bear in mind that he is a university professor who actually does
scientific research and publishes scientific papers, rather than an
amateur.
You might consider 0.2 trillion unbound planetary-mass objects
trivial, but I think if you had predicted them then you would be
singing quite a different tune.
RLO
Fractal Cosmology
Robert L. Oldershaw
>
> A proton (Hydrogen) is about 0.8 fm, and Uranium is [1] roughly 175,000
> fm. So taking 10km as the middle of the neutron star range gives a rough
> upper limit of...two million kilometers? Using *your* "predicted" (when
Sigh,
There is a simple formula for calculating the radii of nuclei.
It is: R = (1.3 fermi)(atomic number)^1/3
You can find versions of this approximation in virtually any book on
nuclear physics.
I have no idea how you can believe a number like 175,000 fm.
But there is something seriously wrong with what you say, which is not
all that surprising.
RLO
Fractal Cosmology
Phillip Helbig---undress to reply
Oldershaw" <rlold...@amherst.edu> writes:
> Have you read Mike Hawkins' preprint: "The case for primordial black
> holes as dark matter"?
>
> I think that he would vigorously disagree with your statement above.
Probably.
> And bear in mind that he is a university professor who actually does
> scientific research and publishes scientific papers, rather than an
> amateur.
AFAIK, he is not a professor (not that that is really relevant here):
http://www.roe.ac.uk/roe/staff/index.html
I think it is fair to say that Mike's ideas here are regarded with some
scepticism within the community.
Of course, there have been many debates within astronomy, with
professors on both sides.
He had a very good idea, based on observations originally made for
something completely different, and it made some testable predictions.
One was already confirmed when his first Nature paper on this was
published (it was suggested by the referee). However, other predictions
have been falsified. It doesn't even look like he could save the
appearances by using epicycles, not that that should appeal to you.
His work has been discussed here many times, with references.
Thomas Womack
eric gisse <jowr.pi...@gmail.com> wrote:
>A proton (Hydrogen) is about 0.8 fm, and Uranium is [1] roughly 175,000
>fm.
That figure for uranium is an orbital radius rather than a nuclear
radius - it's half the distance between uranium atoms in a crystal of
uranium metal. Uranium nucleus is about 14 femtometres across.
Tom
Phillip Helbig---undress to reply
Oldershaw" <rlold...@amherst.edu> writes:
> On Aug 23, 3:37 am, eric gisse <jowr.pi.ons...@gmail.com> wrote:
> >
> > A proton (Hydrogen) is about 0.8 fm, and Uranium is [1] roughly 175,000
> > fm. So taking 10km as the middle of the neutron star range gives a rough
> > upper limit of...two million kilometers? Using *your* "predicted" (when
> ----------------------------------------------------------------
>
> Sigh,
>
> There is a simple formula for calculating the radii of nuclei.
>
> It is: R = (1.3 fermi)(atomic number)^1/3
>
> You can find versions of this approximation in virtually any book on
> nuclear physics.
>
> I have no idea how you can believe a number like 175,000 fm.
I have to agree with Robert here. It looks like Eric quoted a number
for a hydrogen NUCLEUS but for a uranium ATOM (possibly ionized). Atoms
can be quite large, especially if they are not in the ground state. The
formula above shows that the size is given by the number of nucleons,
which makes sense only if they are densely packed. (Thus, it should be
"atomic weight" rather than "atomic number" above.) The lower limit is
obvious. The upper limit is more complicated, but completely well
understood within nuclear physics (which is an effective theory and
works fine---there are no mysteries---even if the underlying theory is
not completely understood). Stars, of whatever type, have a range of
sizes also given by physics and also by nuclear physics, however there
is no Great Chain of Being which makes this a simple scaling relation.
eric gisse
> On Aug 22, 6:00 pm, eric gisse <jowr.pi.ons...@gmail.com> wrote:
>>
>> Like for example, if one theory predicts dark matter is made of solar
>> mass MACHOs but years of surveys only find some planets that make up
>> a few percentage points, I suppose you would consider that an example
>> of a theory that is fundamentally wrong.
> ----------------------------------------------------------------------
-
> -------------------------
>
> Have you read Mike Hawkins' preprint: "The case for primordial black
> holes as dark matter"?
No, Robert. All those times I've quoted it directly and argued against
its' contents were just elaborate ruses.
Hawkins doesn't even meaningfully address the MACHO surveys. He just
wishes and hopes.
>
> I think that he would vigorously disagree with your statement above.
Because much like yourself, Hawkins has been pushing the same ideas for
the past thirty years. I've written about them previously, and the
problems are manifold.
This is nothing new. Hawkins is wrong. There is an abundance of
literature on why Hawkins is wrong. Why Hawkins is wrong has been
explained to you before, and doesn't need to be explained for the n+1'th
time just because you weren't listening hte previous n times.
>
> And bear in mind that he is a university professor who actually does
No, he isn't.
> scientific research and publishes scientific papers, rather than an
> amateur.
I can just imagine the huff and sneer that came after the period.
>
> You might consider 0.2 trillion unbound planetary-mass objects
> trivial, but I think if you had predicted them then you would be
> singing quite a different tune.
Why do I have to keep repeating myself?
Even *IF* the amount is correct (and both you and the author of the
study question that), the integrated mass value of all those objects is
in the neighborhood of a few percent of the entire required mass budget
to satisfy what is required.
You also predict a ton of objects in the tenths to integer solar mass
range, which have happened to evade the last 15 years of MACHO surveys.
You have no explanation for this.
These surveys, as I have repeatedly given literature citations to, are
not incompatible with the discovered planets. But they are - without any
doubt - incompatible with theories of dark matter that are based on
MACHOs.
When you have an actual argument as to how you can have MACHOs being
dark matter while escaping all known MACHO surveys then there'll be
something to talk about.
>
> RLO
> Fractal Cosmology
Robert L. Oldershaw
>
> He had a very good idea, based on observations originally made for
> something completely different, and it made some testable predictions.
> One was already confirmed when his first Nature paper on this was
> published (it was suggested by the referee). However, other predictions
> have been falsified. It doesn't even look like he could save the
> appearances by using epicycles, not that that should appeal to you.
>
> His work has been discussed here many times, with references.
If you have read Mike's most recent preprint, can you make brief,
specific, and hopefully more substantive comments on exactly where you
think his scientific arguments are weak or appear to be refuted by
empirical evidence.
Let's confine the discussion to the contents of the specific preprint:
http://arxiv.org/abs/1106.3875 .
RLO
Discrete Scale Relativity
Robert L. Oldershaw
wrote:
>
> It is: R = (1.3 fermi)(atomic number)^1/3
Excuse the typo. R = (1.3 fermi)(atomic mass)^1/3
RLO
Fractal Cosmology
eric gisse
> for a hydrogen NUCLEUS but for a uranium ATOM (possibly ionized).
Correct. I wasn't paying sufficient attention, which then causes me to
look like an idiot.
On the other hand, I specifically searched for nuclei as opposed to atom
(because I know the difference) and the reference says 'nuclei'.
Probably should have noticed.
[...]
eric gisse
This is an especially aggrivating and stupid aspect of your personality,
Robert. I'm rather pissed off that I didn't immediately remember I went
over this with you all the way back in June (All those 3 months ago, aka
'forever ago') you cited arXiv:1106.3875v1; under the theory that MRS
Hawkins is an unfamiliar personality to me. Then tell me to 'read it
carefully' [1] . Apparently not expecting me to actually do so, or
whatever.
So being bored of gazing into my navel I take a shot at reading it, and
I spot a problem or five. I also remark about how Hawkins' arguments
have been chewed up and spat out in the literature rather consistently
since I was like three years old. I reply as such. [2]
This is where things end, because apparently you decided that you'd post
to the thread a few more times then ignore what I wrote. Then you have
the raw audacity to ask me whether I've *read the goddamn paper* before?
It'd be nice to carry on a technical discussion with you in which you
carry your end of the bargain by not running away when I make the effort
to bring out technical details.
(Normally I would have merely cited the google groups thread, but gg is
being a useless heap tonight)
[1]
http://groups.google.com/group/sci.astro.research/msg/0a291f1edfb8ec46?
dmode=source
[2]
http://groups.google.com/group/sci.astro.research/msg/e5844576e1ddcecb?
dmode=source
Robert L. Oldershaw
<hel...@astro.multiCLOTHESvax.de> wrote:
>
> This is a straw-man argument. Most theories are not theories of
> everything which unanimously predict everything of interest. Most
> theories have some parameters which (as far as we know now) must be
> determined by observation. This does not mean that the theory is
> fundamentally wrong. For example, many new species of animals and
> plants are still being discovered. Our theories of biology are not
> fundamentally wrong on the grounds that they were not all predicted. In
Sigh,
This is quite beyond the pale, or even the pail.
You set up the incorrect statement: A theory should "predict
everything".
Then you courageously knock down that foolishly absolute argument.
The only problem is that I have never said anything like that
statement, and you can look through everything I have ever written to
verify that I have never said it. I do not deal in such
unsophisticated philosophical posturing.
It is you who have given us the straw-man argumentation.
----------------------
And, while the original naive steady-state model has safely been put
to rest, there are much more sophisticated "steady-state" models that
involve oodles of "local" change on every observable Scale, but are
globally eternal and statistically unchanging overall.
We can do better,
RLO
http://www3.amherst.edu/~rloldershaw
eric gisse
[...]
> And, while the original naive steady-state model has safely been put
> to rest, there are much more sophisticated "steady-state" models that
> involve oodles of "local" change on every observable Scale, but are
> globally eternal and statistically unchanging overall.
>
> We can do better,
> RLO
> http://www3.amherst.edu/~rloldershaw
>
But wouldn't that be a textbook example of what you would refer to as an
epicycle and the other various things you say about a dead theory?
Phillip Helbig---undress to reply
<jowr.pi...@gmail.com> writes:
> "Robert L. Oldershaw" <rlold...@amherst.edu> wrote in
> news:mt2.0-25855...@hydra.herts.ac.uk:
>
> [...]
>
> > And, while the original naive steady-state model has safely been put
> > to rest, there are much more sophisticated "steady-state" models that
> > involve oodles of "local" change on every observable Scale, but are
> > globally eternal and statistically unchanging overall.
> >
> > We can do better,
> > RLO
> > http://www3.amherst.edu/~rloldershaw
> >
>
> But wouldn't that be a textbook example of what you would refer to as an
> epicycle and the other various things you say about a dead theory?
Bazinga! The "refinements" of epicycles are better examples of
epicycles than epicycles themselves.
Phillip Helbig---undress to reply
Oldershaw" <rlold...@amherst.edu> writes:
> If you have read Mike's most recent preprint, can you make brief,
> specific, and hopefully more substantive comments on exactly where you
> think his scientific arguments are weak or appear to be refuted by
> empirical evidence.
>
> Let's confine the discussion to the contents of the specific preprint:
> http://arxiv.org/abs/1106.3875 .
OK. I'll be on holiday soon and will take it along and read it. From
what I've seen so far, it looks like a re-tread of previous papers,
ignoring most or all criticism of his work rather than replying to it.
He tries to make the MACHO results compatible with his ideas. Whether
or not that is the case, they are ruled out on other grounds.
More when I return.
Phillip Helbig---undress to reply
Oldershaw" <rlold...@amherst.edu> writes:
> On Aug 23, 3:33 am, Phillip Helbig---undress to reply
> <hel...@astro.multiCLOTHESvax.de> wrote:
> >
> > This is a straw-man argument. Most theories are not theories of
> > everything which unanimously predict everything of interest. Most
> > theories have some parameters which (as far as we know now) must be
> > determined by observation. This does not mean that the theory is
> > fundamentally wrong. For example, many new species of animals and
> > plants are still being discovered. Our theories of biology are not
> > fundamentally wrong on the grounds that they were not all predicted. In
> ------------------------------------------------------------------------------------
>
> Sigh,
>
> This is quite beyond the pale, or even the pail.
>
> You set up the incorrect statement: A theory should "predict
> everything".
>
> Then you courageously knock down that foolishly absolute argument.
Here is what I said:
Message-ID: <mt2.0-2310...@hydra.herts.ac.uk>
In article <mt2.0-28247...@hydra.herts.ac.uk>, "Robert L.
Oldershaw" <rlold...@amherst.edu> writes:
> Ideally we want theories that make definitive predictions that tell us
> whether the theory is fundamentally right, or fundamentally wrong.
Agreed.
> In the latter case, one does not "modify" the fundamentally wrong
> theory. One seeks a new model based on a new theoretical principle.
This is a straw-man argument. Most theories are not theories of
everything which unanimously predict everything of interest.
Where, exactly, did I
> set up the incorrect statement: A theory should "predict
> everything".
???
YOU said that an acceptable theory should be able to make predictions
out of the box and should be rejected if it needs further input from
observations.
> The only problem is that I have never said anything like that
> statement, and you can look through everything I have ever written to
> verify that I have never said it.
I never claimed you did.
This is not the first time you have snipped a text and then
misrepresented it. I'm not sure if it is due to incompetence or a
deliberate intent to spite.
People criticise not only your DSR but also your mode of argumentation,
your igoring constructive criticism, your selective use of literature
citations. What do you want to achieve and do you think that your
current strategy is the way to achieve it?
Robert L. Oldershaw
>
> YOU said that an acceptable theory should be able to make predictions
> out of the box and should be rejected if it needs further input from
> observations.
Just in from the Harvard-Smithsonian Center for Astrophysics.
http://www.sciencedaily.com/releases/2011/10/111017124344.htm
CDM scenarios predict that the putative cold "WIMPs" should form
density cusps at the centers of galaxies, i.e., density peaking toward
the center.
In the past, (1) this prediction, and (2) the prediction of many
hundreds of "CDM halo objects" orbiting galaxies, have repeatedly
conflicted with what we actually see in the observable universe.
The above linked research concerns two dwarf galaxies that have now
been studied in considerable detail.
The results are in strong conflict with "WIMP" model predictions and
standard CDM cosmology, in general. The distribution of the dark
matter for these galaxies, which constitutes 99% of their mass, is
definitely not cusped, but rather is evenly distributed.
Looks like yet another compelling argument for open-mindedness in the
dark matter search.
RLO
http://www3.amherst.edu/~rloldershaw
eric gisse
> On Aug 26, 4:22 am, Phillip Helbig---undress to reply
> <hel...@astro.multiCLOTHESvax.de> wrote:
>>
>> YOU said that an acceptable theory should be able to make predictions
>> out of the box and should be rejected if it needs further input from
>> observations.
> ----------------------------------------------------------------------
-
> ----------------------------
>
> Just in from the Harvard-Smithsonian Center for Astrophysics.
>
> http://www.sciencedaily.com/releases/2011/10/111017124344.htm
the nonsense that is the sciencedaily article.
http://arxiv.org/abs/1108.2404
Note how I managed to link the abstract rather than the PDF.
As an aside into a general theory of mine, could you tell us whether you
actually studied and understood the statistical methods used in the
article? You've repeatedly stated you don't trust any moderately complex
statistical analysis so I'm wondering if that belief holds when you
believe you have something that agrees with you. Not relevant to the
article but highly relevant to a personal theory of mine...
>
> CDM scenarios predict that the putative cold "WIMPs" should form
> density cusps at the centers of galaxies, i.e., density peaking toward
> the center.
First off, the composition of dark matter is irrelevant here as the CDM
theory does not depend on dark matter's composition. In fact, cold dark
matter covers a rather wide range of scenarios up to and including your
numerology that states a bunch of small black holes constitute dark
matter. The previous falsification of that aside, it is worth keeping in
mind the implications of your claim.
The article highlights something that has been relatively well known for
years: the various models for galactic halos have never *EVER* been
meaningfully constrained by the galactic cores because the data has
always been sparse.
I have in my mind an article that I read a few years ago that discusses
the various possible features for core DM distributions in halo models
that are consistent with observation. While I cannot recall the
reference, I remember the various models being highly various in what
happens at the center.
As it turns out, if one reads the actual article, is *EXACTLY* what has
happened. All that was done here was a falsification of the NFW model
for galactic halos, which isn't a huge surprise given the recent
observation of triaxiality in the MW halo and the simple fact that the
NFW model is the cosmological equivalent of the spherical cow.
>
> In the past, (1) this prediction, and (2) the prediction of many
> hundreds of "CDM halo objects" orbiting galaxies, have repeatedly
> conflicted with what we actually see in the observable universe.
>
> The above linked research concerns two dwarf galaxies that have now
> been studied in considerable detail.
is how science works.
Did you know it was only within the last year or so that we actually
obtained a measurement of the Milky Way halo that finally established
that they aren't spherical as our models have been assuming so far?
Try not to make so much hay out of something innocuous, it makes you
look petty.
>
> The results are in strong conflict with "WIMP" model predictions and
> standard CDM cosmology, in general.
are actually saying is that the results are in strong conflict with what
you've been advocating.
Of course you won't feel this way, but you won't be able to muster an
argument that explains otherwise. I, however, encourage a response that
proves otherwise.
> The distribution of the dark
> matter for these galaxies, which constitutes 99% of their mass, is
> definitely not cusped, but rather is evenly distributed.
"Cosmologists use powerful computers to simulate this process.
Their simulations show that dark matter should be densely packed
in the centers of galaxies."
I would like to see some references for this claim. Dark matter modeling
is well known. I'm thinking along the lines of the Millennium II
simulation which modeled formation down to the galactic level. I,
however, don't remember the simulation ever reaching the level of
resolution on sattelite galaxies that would allow such a conclusive
statement.
So there are one of three choices here, as far as I can see:
1) I am misremembering, and it did, and the result is correct.
2) I am not misremembering. In which case the distribution in a dwarf
galaxy will be meaningless.
3) A simulation has been done with sufficient resolution but I merely
have not heard about it.
Would you like to provide some references, Robert?
Or is this one of those situations where you read some article written
for a lay audience and literally looked no further because it fits in
well with your agenda?
Reading the published article would be instructive, as the difficulties
and semi-contradictory claims WRT modeling are discussed in actual
legitimate detail rather than in soundbites and lay-person level detail.
Since its' a 20 page article that's relatively dense, for the moment I'm
settling for reading the abstract, first page, and the conclusion
section. A fuller read will proceed over the rest of the week when I
have time.
>
> Looks like yet another compelling argument for open-mindedness in the
> dark matter search.
estimate on the number of stars by a factor of 4 to 400 billion, which
is 300 billion larger than what I thought.
So when I was discussing those MOA group results I was basing the
irrelevance of the result on the assumption the baryonic mass content of
the galaxy was about a hundred billion solar masses. Turns out I was a
factor of 4 wrong, and those Jupiter class worlds now constitute about a
quarter of a percent of the galactic baryonic mass budget.
Even less than before!
>
> RLO
> http://www3.amherst.edu/~rloldershaw
>
Robert L. Oldershaw
>
> 1) I am misremembering,
---------------------------------------------------------------------------------------
Perhaps a simple direct quotation from the authors that actually did
the research will help to cut through your hand-waving and
obfuscation.
"Our measurements contradict a basic prediction about the structure of
the cold dark matter in dwarf galaxies. Unless or until theorists can
modify that prediction, cold dark matter is inconsistent with our
observational data." - Matt Walker (lead author)
That seems fairly clear to me.
RLO
http://www3.amherst.edu/~rloldershaw
eric gisse
> On Oct 18, 5:19 am, eric gisse <jowr.pi.ons...@gmail.com> wrote:
>>
>> 1) I am misremembering,
> ----------------------------------------------------------------------
-
> ----------------
>
> Perhaps a simple direct quotation from the authors that actually did
> the research will help to cut through your hand-waving and
> obfuscation.
requisite for making the claims...
>
> "Our measurements contradict a basic prediction about the structure of
> the cold dark matter in dwarf galaxies. Unless or until theorists can
> modify that prediction, cold dark matter is inconsistent with our
> observational data." - Matt Walker (lead author)
>
> That seems fairly clear to me.
I note the ignored fact that this, if one listens to you, is a
falsification of your numerology as well. I note no technical argument
as to why this is not the case as predicted. So when you inevitibly
ignore what I've said and continue to parrot the notion that this
falsifies the concordance cosmology, everyone will get to have a small
laugh about how you are saying your own model is wrong.
Anyway...
What the lead author says isn't technically true, but is OK because the
quote is in the context of a news article which is written for people
who aren't familiar with the field enough to read the actual technical
article.
The actual technical article is here:
http://arxiv.org/abs/1108.2404
Have you looked at it yet? Its' ok if you haven't read it all because
its' long and technical, but have you even looked?
What is actually says is the NFW model for CDM has been excluded at high
confidence levels, which to be honest are only two sigma results. A two
sigma observation in cosmology isn't nearly as much as you'd wish it to
be.
But taken at face value this tells us something we largely already know:
The true distribution for dark matter inside a galaxy is not the
spherical donut that the NFW model has been assuming for the past 30
years.
What you have to keep in mind is that model has been a successful model
of the distribution for dark matter in a galaxy since the 70's. It is
only within the last 5 years that we've had enough advances in precision
cosmology to move beyond the spherical cow approximation for dark matter
into probing core structure and the true three dimensional structure, eg
recent results of observing triaxiality in the MW DM distribution.
So the only serious implication here is we need to think up a better
model for dark matter at least in dwarf galaxies. The NFW model might
very well remain true enough for galaxies themselves, but we'll need
decent amounts of core data to constrain the model.
Of course, if you'd like to just sit there and crow about how the CDM
model has been falsified while ignoring what the article actually sayd
you are more than welcome to do it.
Just not here.
We have sci.physics / sci.physics.relativity for that.
Phillip Helbig---undress to reply
> "Our measurements contradict a basic prediction about the structure of
> the cold dark matter in dwarf galaxies. Unless or until theorists can
> modify that prediction, cold dark matter is inconsistent with our
> observational data." - Matt Walker (lead author)
discussed here not that long ago. It does seems that there is a
conflict between theory and observation here (which, however, like in
thousands of other cases, is probably NOT a sign that "the entire
paradigm is wrong"). The most obvious resolution (pun intended) would
be that the simulations are not exact enough. This is what many people
thought, but it turns out that higher-resolution simulations tend to
make the problem worse. Others see it as evidence for MOND. Still
others think the observations are complete: dwarf galaxies near the
Milky Way are difficult to see through the Milky Way, and of course the
distribution of dark matter there is not directly observed but inferred.
My guess is a combination of the third possibility (observations being
interpreted too hastily) and the first (but not involving the resolution
or nature of the dark matter, but rather involving "gastrophysics",
feedback etc).
Robert L. Oldershaw
>
> My guess is a combination of the third possibility (observations being
> interpreted too hastily) and the first (but not involving the resolution
> or nature of the dark matter, but rather involving "gastrophysics",
> feedback etc).
Your comments, and those of Mr. Gisse, speak only of coming up with ad
hoc fixes for the problems, i.e., adjustments to the model or fault-
finding with the simulations/analysis.
To me the new results clearly add futrther evidence to what was
already well-known.
The "standard" CDM model predicts that (1) there will be a very large
number of "DM haloes" surrounding galaxies, and (2) that the dark
matter distribution in both dwarf and other types of galaxies will be
centrally cusped.
Nature says: (1) NO; (2) NO.
What is it about "NO" that you do not understand?
RLO
Discrete Scale Relativity
Robert L. Oldershaw
>
> So the only serious implication here is we need to think up a better
> model for dark matter at least in dwarf galaxies. The NFW model might
> very well remain true enough for galaxies themselves, but we'll need
> decent amounts of core data to constrain the model.
But is this not the "save the phenomenon" strategy for doing
cosmology?
Would it hurt to consider alternatives to CDM and the entire
"standard" cosmological paradigm?
Or would that be blasphemy?
RLO
Unbounded Fractal Cosmology
Richard D. Saam
> In article<mt2.0-29237...@hydra.herts.ac.uk>, "Robert L.
> Oldershaw"<rlold...@amherst.edu> writes:
>
>> "Our measurements contradict a basic prediction about the structure of
>> the cold dark matter in dwarf galaxies. Unless or until theorists can
>> modify that prediction, cold dark matter is inconsistent with our
>> observational data." - Matt Walker (lead author)
>
>
> interpreted too hastily) and the first (but not involving the resolution
> or nature of the dark matter, but rather involving "gastrophysics",
> feedback etc).
may have a good insight into astrophysical structure
in his 1889 painting 'Starry Night'
http://www.googleartproject.com/museums/moma/the-starry-night
with its large to small fluidic connected dissimilar entities.
As far as I know, CDM theory does not have the concept of viscosity
(momentum transfer across an area)
that would substantiate Van Gogh's image
that would draw more on classical turbulence theory as per:
J. O. Hinze, 'Turbulence' 1975
Richard D. Saam
Robert L. Oldershaw
>
> > My guess is a combination of the third possibility (observations being
> > interpreted too hastily) and the first (but not involving the resolution
> > or nature of the dark matter, but rather involving "gastrophysics",
> > feedback etc).
>
> I think Vincent Van Gogh
> may have a good insight into astrophysical structure
> in his 1889 painting 'Starry Night'http://www.googleartproject.com/museums/moma/the-starry-night
> with its large to small fluidic connected dissimilar entities.
> As far as I know, CDM theory does not have the concept of viscosity
> (momentum transfer across an area)
> that would substantiate Van Gogh's image
> that would draw more on classical turbulence theory as per:
> J. O. Hinze, 'Turbulence' 1975
This is beginning to sound like theater of the absurd.
I like Van Gogh's art very much, but I don't think he was portraying
the way the world is. Rather he was portraying the way the world
appeared to him. It was the era of impressionism, right?
RLO
http://www3.amherst.edu/~rloldershaw
[Mod. note: further art criticism should be taken elsewhere -- mjh]
Phillip Helbig---undress to reply
>
> Your comments, and those of Mr. Gisse, speak only of coming up with ad
> hoc fixes for the problems, i.e., adjustments to the model or fault-
> finding with the simulations/analysis.
galaxies in the Local Group as predicted by DSR?
> To me the new results clearly add futrther evidence to what was
> already well-known.
>
> The "standard" CDM model predicts that (1) there will be a very large
> number of "DM haloes" surrounding galaxies, and (2) that the dark
> matter distribution in both dwarf and other types of galaxies will be
> centrally cusped.
>
> Nature says: (1) NO; (2) NO.
>
> What is it about "NO" that you do not understand?
easy. I'm not saying there is no conflict between theory and
observations (science is an interplay between theory and observations),
merely that it is not as cut and dried as you claim.
Phillip Helbig---undress to reply
> On Oct 18, 3:14 pm, eric gisse <jowr.pi.ons...@gmail.com> wrote:
> >
> > model for dark matter at least in dwarf galaxies. The NFW model might
> > very well remain true enough for galaxies themselves, but we'll need
> > decent amounts of core data to constrain the model.
>
> But is this not the "save the phenomenon" strategy for doing
> cosmology?
are throwing the baby out with the bathwater. It's like those
creationists who argue that any debate WITHIN evolutionary biology means
that the whole idea of evolution is bogus.
> Would it hurt to consider alternatives to CDM and the entire
> "standard" cosmological paradigm?
>
> Or would that be blasphemy?
Thomas Womack
>easy.
(for something like the UMi dwarf which is far from the galactic plane
so you don't have to worry too much about differential extinction)
I would have thought that the techniques for producing those
gorgeously clear colour-magnitude diagrams of globular clusters,
taking two HST exposures at fairly different epochs and filtering by
proper motion, would be enough ... though I suppose that the UMi dwarf
is a lot bigger than even the ACS field.
Tom
Phillip Helbig---undress to reply
> >Have you ever observed a dwarf galaxy through the Milky Way? It is not
> >easy.
>
> What's the issue - distinguishing field-stars from the galaxy stars?
> (for something like the UMi dwarf which is far from the galactic plane
> so you don't have to worry too much about differential extinction)
> I would have thought that the techniques for producing those
> gorgeously clear colour-magnitude diagrams of globular clusters,
> taking two HST exposures at fairly different epochs and filtering by
> proper motion, would be enough ... though I suppose that the UMi dwarf
> is a lot bigger than even the ACS field.
pictures of recently discovered(!) dwarf galaxies in our cosmic
backyard. It took the audience a few seconds to even recognise some of
them. OK, a projection screen in a lecture hall is not ideal, but
traditional galaxy pictures (which she also showed in the same talk
showed up in all the expected glory). I'm pretty sure she knows what
she was talking about.
David Staup
> Oldershaw" <rlold...@amherst.edu> writes:
>
>> > My guess is a combination of the third possibility (observations being
>> > interpreted too hastily) and the first (but not involving the
>> > resolution
>> > or nature of the dark matter, but rather involving "gastrophysics",
>> > feedback etc).
>> ----------------------------------------------------------
>>
>> Your comments, and those of Mr. Gisse, speak only of coming up with ad
>> hoc fixes for the problems, i.e., adjustments to the model or fault-
>> finding with the simulations/analysis.
>
> Can you point us poor souls to the distribution of dark matter in dwarf
> galaxies in the Local Group as predicted by DSR?
>
if, in fact, dark matter does not exist in nature, then no theory should
predict it.
your logic is flawed
eric gisse
> On Oct 18, 4:21 pm, Phillip Helbig---undress to reply
> <hel...@astro.multiCLOTHESvax.de> wrote:
>>
>> My guess is a combination of the third possibility (observations
being
>> interpreted too hastily) and the first (but not involving the
resolution
>> or nature of the dark matter, but rather involving "gastrophysics",
>> feedback etc).
> ----------------------------------------------------------
>
> Your comments, and those of Mr. Gisse, speak only of coming up with ad
> hoc fixes for the problems, i.e., adjustments to the model or fault-
> finding with the simulations/analysis.
maneuvering you have done to disregard all the evidence that falsifies
your numerology.
Speaking of your numerology, does it have anything to say about the dark
matter distribution about a galaxy or is it silent in that respect?
>
> To me the new results clearly add futrther evidence to what was
> already well-known.
that dark matter halos are not spherically symmetric?
>
> The "standard" CDM model predicts that (1) there will be a very large
> number of "DM haloes" surrounding galaxies, and (2) that the dark
> matter distribution in both dwarf and other types of galaxies will be
> centrally cusped.
>
> Nature says: (1) NO; (2) NO.
this is true for out galaxy and others.
As for #2, all that has been disproved is the commonly used NFW model
which you apparently don't understand.
If I assume a spherical Earth and find that satellite orbits are goofy
in that model, is Newtonian gravitation wrong or is the model wrong?
>
> What is it about "NO" that you do not understand?
>
> RLO
> Discrete Scale Relativity
>
eric gisse
> On Oct 18, 3:14 pm, eric gisse <jowr.pi.ons...@gmail.com> wrote:
>>
>> So the only serious implication here is we need to think up a better
>> model for dark matter at least in dwarf galaxies. The NFW model might
>> very well remain true enough for galaxies themselves, but we'll need
>> decent amounts of core data to constrain the model.
> ----------------------------------------------------------------------
-
> ---
>
> But is this not the "save the phenomenon" strategy for doing
> cosmology?
The theory of dark matter only makes meaningful predictions about the
distribution of dark matter on a scale as small as a galaxy if one
creates a simulation of the universe with that resolution. We've (kinda)
done that through the Millennium and Millennium II simulations but as
has been pointed out to you, the resolution is insufficient to discuss
meaningfully the distribution in dwarf galaxies or the central parts of
a galaxy.
>
> Would it hurt to consider alternatives to CDM and the entire
> "standard" cosmological paradigm?
MOND and related theories have far, far bigger problems than what dark
matter has to contend with because of gravitational lensing in clusters
and such. So that's out.
Your numerology makes no predictions about structures that large, and
completely fails on the stellar scale. So that's out.
Actually, since you think this result falsifies dark matter, your
numerology is falsified by extension. I've brought this point up several
times but you are either unwilling or unable to discuss it.
Solid state theory and such have been dead for decades. So that's out.
The list of credible alternative theories is rather short, and are all
almost exclusively modifications of the concordance cosmology to make
some sort of extra thingy that another theory predicts work.
>
> Or would that be blasphemy?
>
> RLO
> Unbounded Fractal Cosmology
>
'blasphemy' in the context of science? The word "projection" comes to
mind, for no apparent reason.
eric gisse
news:mt2.0-10063...@hydra.herts.ac.uk:
> "Phillip Helbig---undress to reply" <hel...@astro.multiCLOTHESvax.de>
> wrote in message news:mt2.0-13830...@hydra.herts.ac.uk...
>> In article <mt2.0-25099...@hydra.herts.ac.uk>, "Robert L.
>> Oldershaw" <rlold...@amherst.edu> writes:
>>
>>> > My guess is a combination of the third possibility (observations
>>> > being interpreted too hastily) and the first (but not involving
>>> > the resolution
>>> > or nature of the dark matter, but rather involving
>>> > "gastrophysics", feedback etc).
>>> ----------------------------------------------------------
>>>
>>> Your comments, and those of Mr. Gisse, speak only of coming up with
>>> ad hoc fixes for the problems, i.e., adjustments to the model or
>>> fault- finding with the simulations/analysis.
>>
>> Can you point us poor souls to the distribution of dark matter in
>> dwarf galaxies in the Local Group as predicted by DSR?
>>
>
> Can you point to a prediction for the existance of dark matter?
http://apod.nasa.gov/apod/ap060824.html
>
> if, in fact, dark matter does not exist in nature, then no theory
> should predict it.
>
> your logic is flawed
>
the observations that indicate dark matter.
Please try a level of argumentation that's beyond the dyslexic troll
that inhabits sci.physics.*, it will get you more detailed answers.
Thomas Womack
>pictures of recently discovered(!) dwarf galaxies in our cosmic
>backyard. It took the audience a few seconds to even recognise some of
>them.
only as statistically significant over-densities of stars in
particular regions of the SDSS colour-magnitude space.
http://www.physorg.com/news87576087.html and
http://arxiv.org/abs/astro-ph/0608448 ;
http://arxiv.org/pdf/0706.0516v2 for some Keck velocity measurements
suggesting that some of these dwarf galaxies have ridiculously high
masses for their luminosity. The sample sizes involved are pretty
tiny.
[http://www.eso.org/public/news/eso1128/ is open clusters rather than
dwarf galaxies, and the issue there is mostly reddening since it's a
survey done with a new wide-field IR telescope, but it's not always
at all obvious from the thumbnail images in
http://www.eso.org/public/archives/images/screen/eso1128a.jpg where
the cluster actually is]
Tom
Richard D. Saam
> I like Van Gogh's art very much, but I don't think he was portraying
> the way the world is. Rather he was portraying the way the world
> appeared to him. It was the era of impressionism, right?
painted an easily understandable universe impression 'Starry Night'
involving a fluidic character indicative of discrete entities
that may be subsequently reflected in observational reality.
Evidence the work of Marian Smoluchowski circa 1917
and the work of Camp and Stein in the 1940's
wherein discrete particles are formed in a fluid substrate
under dissipative energy expressing itself as shear.
Such a concept is used in design of:
1. floc formation in activated sludge process
2. rock crushing to gravel size
3. cosmetic component particle sizing
4 to puree vegetables in a blender
4. post analysis of trade tower fall creation of an ubiquitous dust.
Astrophysically; galaxies, stars and other celestial body sizes
may be a result of the energy dissipation environment
at their creation.
How does your discrete celestial object sizing
differ from this long standing applied concept?
Richard D. Saam
[Mod. note: quoted text trimmed -- mjh]
Phillip Helbig---undress to reply
No, but it is (indirectly, of course) observed. It is a mistake to
think that science should be able to predict everything. Yes, there
might conceivably be another explanation, but it has to stand up to the
usual demands (not be ad-hoc, not be even more complicated, be
falsifiable etc).
Phillip Helbig---undress to reply
> If I assume a spherical Earth and find that satellite orbits are goofy
> in that model, is Newtonian gravitation wrong or is the model wrong?
discovering that the Earth is not a perfect sphere does NOT mean that it
is acceptable to think of it as a cube.
Phillip Helbig---undress to reply
> > Can you point to a prediction for the existance of dark matter?
>
>
> http://apod.nasa.gov/apod/ap060824.html
To be fair, I think that this is better classified as an observation,
not a prediction.
David Staup
galaxies in the Local Group as predicted by DSR?"
asking here.
and again I ask can you? All theories pertaining to the effect are theories
that predict a cause for the effect. Some have targets for verification by
observation that's a prediction, to my knowledge none have been verified.
You may have meant to say it differently but you asked for a prediction and
now you say it's a mistake to expect predictions.
again I say, your logic is flawed
Eric Flesch
>David Staup <dst...@sbcglobal.net> wrote in
>
>Bullet cluster.
>http://apod.nasa.gov/apod/ap060824.html
>the observations that indicate dark matter.
not directly observed by any instrument, but is overlaid to represent
the matter that presumably must be there for the observed
gravitational lensing to occur.
But there is an elephant in the room, and that is the necessary
assumption of a flat space-time manifold on which these calculations
are made. An alternative manifold would be a brane of an underlying
large dimension, which has surface tension such that the visible
galaxy cluster deforms it into a bowl contour. Light travelling along
the bowl would also show the gravitational lensing, without the need
for additional matter.
So the Bullet cluster shows the presence of "dark matter" insofar as
that term is used to mean "something extra", and not to mean "matter"
in particular.
Eric Flesch
eric gisse
that dark matter does not interact with baryonic matter.
eric gisse
not mean the theory is wrong. A point that may be lost on Robert.
eric gisse
@hydra.herts.ac.uk:
> On Thu, 20 Oct 11, eric gisse <jowr.pi...@gmail.com> wrote:
>>David Staup <dst...@sbcglobal.net> wrote in
>>> Can you point to a prediction for the existance of dark matter?
>>
>>Bullet cluster.
>>http://apod.nasa.gov/apod/ap060824.html
>>If dark matter doesn't exist in nature, then the theory has to explain
>>the observations that indicate dark matter.
>
> The link displays a composite "lensing map". The blue-tinted part is
> not directly observed by any instrument, but is overlaid to represent
> the matter that presumably must be there for the observed
> gravitational lensing to occur.
>
> But there is an elephant in the room, and that is the necessary
> assumption of a flat space-time manifold on which these calculations
> are made.
Space-time retains curvature, otherwise gravitational lensing wouldn't
work.
What is true is that the calculation usually rest on assuming a flat
manifold with a perturbation for the calculation of lensing, but that's
perfectly OK because the fields are weak. Plus the manifold +
perturbation are still collectively curved.
> An alternative manifold would be a brane of an underlying
> large dimension, which has surface tension such that the visible
> galaxy cluster deforms it into a bowl contour. Light travelling along
> the bowl would also show the gravitational lensing, without the need
> for additional matter.
maneuver, I'll take it seriously. The community has had 2006 to pull it
off and to my knoweledge hasn't managed to do it yet.
>
> So the Bullet cluster shows the presence of "dark matter" insofar as
> that term is used to mean "something extra", and not to mean "matter"
> in particular.
>
> Eric Flesch
>
still manage to get the correct result?
Phillip Helbig---undress to reply
> galaxies in the Local Group as predicted by DSR?"
>
> asking here.
because it has been observed. Sometimes, stuff like that happens.
Sometimes things are observed first then an explanation is sought.
If you like, a prediction of the observation is that, depending on what
it is, it might be detectable by other means. That's why some people
are looking.
Consider biology: many new species are discovered all the time; no
theory predicts them; this is not a problem.
Phillip Helbig---undress to reply
> The link displays a composite "lensing map". The blue-tinted part is
> not directly observed by any instrument, but is overlaid to represent
> the matter that presumably must be there for the observed
> gravitational lensing to occur.
>
> assumption of a flat space-time manifold on which these calculations
> are made.
> An alternative manifold would be a brane of an underlying
> large dimension, which has surface tension such that the visible
> galaxy cluster deforms it into a bowl contour.
rubber-sheet analogy.
> Light travelling along
> the bowl would also show the gravitational lensing, without the need
> for additional matter.
visible matter.
Eric Flesch
>Are there credible alternative theories that say it isn't matter and
>still manage to get the correct result?
certainly expect it's doable. I see cross-listed papers on ArXiv
dealing with large extra dimensions, so there is activity...
Eric F.
Eric Flesch
>But what causes the deformation? What you are suggested sounds like the
>rubber-sheet analogy.
large extra dimension. This model is possible because gravity has not
been unified with GR. I see gr-qc papers on gravity acting thusly.
Eric
Robert L. Oldershaw
>
> You seem to be think that traditional science should predict dark matter
> because it has been observed. Sometimes, stuff like that happens.
> Sometimes things are observed first then an explanation is sought.
When the dark matter consitutes the overwhelming majority of all
matter in the universe, one would think "precision cosmology" could
identifiy it specifically and definitively.
But no - it cannot do so.
That tells us something very important.
If we care to be scientific about the issue.
RLO
Discrete Scale Relativity
PS: The argument below involves an inept analogy, once again.
> Consider biology: many new species are discovered all the time; no
> theory predicts them; this is not a problem.
presence and diversity of 90% of observed species.
Cosmology does not have, and badly needs, an overarching new paradigm
(like Darwinian evolution) that can identify and explain the basic
principles upon which nature is based. The dark matter enigma shows
that we are not there yet in cosmology.
eric gisse
@hydra.herts.ac.uk:
But that is neither interesting or science, beacuse that's called
"numerology" among other things.
Hell, as far as I know, string theory hasn't even made it to the point
where it can recover Newtonian gravitation so I am going to be skeptical at
claims that it can correctly model cluster lensing maps without seeing the
result myself.
eric gisse
> On Oct 21, 3:40 am, Phillip Helbig---undress to reply
> <hel...@astro.multiCLOTHESvax.de> wrote:
>>
>> You seem to be think that traditional science should predict dark
matter
>> because it has been observed. Sometimes, stuff like that happens.
>> Sometimes things are observed first then an explanation is sought.
> _____________________________________________
>
> When the dark matter consitutes the overwhelming majority of all
> matter in the universe, one would think "precision cosmology" could
> identifiy it specifically and definitively.
It means our observing hardware is good enough that the systematics are
small, and that we have enough samples that random measurement error are
also small.
Not that you are satisifed with the result.
>
> But no - it cannot do so.
> That tells us something very important.
> If we care to be scientific about the issue.
* Its' equation of state
* An upper bound on its' various scattering cross sections
* That it has been around since the beginning of the universe
* That it is not comprised of anything we currently know, including
neutrinos or black holes.
* Its' distribution in space and time on length scales down to the
galactic level.
Just because you don't think that comes out to mean much doesn't make it
true.
>
> RLO
> Discrete Scale Relativity
>
> PS: The argument below involves an inept analogy, once again.
>
>> Consider biology: many new species are discovered all the time; no
>> theory predicts them; this is not a problem.
>
> The correct analogy would be if biology had no explanation for the
> presence and diversity of 90% of observed species.
>
> Cosmology does not have, and badly needs, an overarching new paradigm
> (like Darwinian evolution) that can identify and explain the basic
> principles upon which nature is based. The dark matter enigma shows
> that we are not there yet in cosmology.
>
been the domain of particle physics?
Restrict yourself to the same tools that are available for dark matter,
and you'll notice that we would also have no idea what the composition
of the rest of the universe is.
Eric Flesch
>Eric Flesch <er...@flesch.org> wrote
>> certainly expect it's doable. I see cross-listed papers on ArXiv
>> dealing with large extra dimensions, so there is activity...
>
>But that is neither interesting or science, beacuse that's called
>"numerology" among other things.
parameters, sets the standard to beat. Relax a little, EG.
Eric F
Richard D. Saam
>
> So far, cosmology has told us the following about dark matter:
>
> * Its' equation of state
PV=nRT=(mass/Molecular Weight)RT
essentially pressureless with a molecular weight on the order of a galaxy.
but also bound by the universe optical density
by which dark matter exists but is not visible
and conforms to the anticipated ~30 percent critical universe mass.
but thermally stable at extremely low temperature through all epochs.
> neutrinos or black holes.
that is physically known
and meets the other * criteria.
(I won't mention it, because it appears to engender ridicule
although its presence is dimensionally obvious)
> galactic level.
through gravitational lensing and galactic rotation anomalies
but these distributions do not appear to meet primordial criteria
for predestined uniform mathematical forms.
Dark matter distribution varies from galaxy to galaxy
in conjunction with wispy weblike intergalactic structures.
Richard D. Saam
eric gisse
news:mt2.0-20136...@hydra.herts.ac.uk:
> On 10/22/11 6:38 AM, eric gisse wrote:
>
>>
>> So far, cosmology has told us the following about dark matter:
>>
>> * Its' equation of state
> essentially pressureless
> PV=nRT=(mass/Molecular Weight)RT
> essentially pressureless with a molecular weight on the order of a
> galaxy.
What would be technically correct would be to say the stress tensor of
dark matter obeys the perfect fluid stress tensor with pressure = 0.
>> * An upper bound on its' various scattering cross sections
> Yes in terms of WIMPS etc
> but also bound by the universe optical density
> by which dark matter exists but is not visible
> and conforms to the anticipated ~30 percent critical universe mass.
WRT baryons and itself but I suppose you could add a photon dependent
cross section to the mix as well.
>> * That it has been around since the beginning of the universe
> Yes, around since the universe beginning
> but thermally stable at extremely low temperature through all epochs.
decoupling. We can't really state for certain anything before that.
>> * That it is not comprised of anything we currently know, including
>> neutrinos or black holes.
> There is one candidate worthy of discussion
> that is physically known
> and meets the other * criteria.
> (I won't mention it, because it appears to engender ridicule
> although its presence is dimensionally obvious)
by other observations so I dunno what you are talking about.
>> * Its' distribution in space and time on length scales down to the
>> galactic level.
> Dark matter distribution is observed
> through gravitational lensing and galactic rotation anomalies
> but these distributions do not appear to meet primordial criteria
> for predestined uniform mathematical forms.
Simulations have shown us what dark matter behaves like, and given
resolution limits on simulations, appears to be what we see.
> Dark matter distribution varies from galaxy to galaxy
> in conjunction with wispy weblike intergalactic structures.
>
> Richard D. Saam
>
to data quality) the NFW profile has been sufficient for modeling what
we see.
brad
> Are there credible alternative theories that say it isn't matter and
> still manage to get the correct result?
http://arxiv.org/pdf/1110.0035v1
Brad
Phillip Helbig---undress to reply
> > still manage to get the correct result?
>
abstract!
Below is the abstract. Let me quote:
"An alternative explanation of the dark matter effect is presented here
by assuming that the empty space of the Universe has a complicated
geometrical structure."
What is the basis for this assumption? Is it much different from
assuming that planets are pushed along by angels?
"It is assumed that the cosmological Lambda term, which is approximately
constant at scales of several Mpc and describes the dark energy, is not
constant at scales of several tenth of Kpc and describes the "dark
matter effect"."
Again, this seems very ad-hoc to me. Note that the OP asked about
CREDIBLE alternative theories.
---------8<-------------------------------------------------------------------
The observed excess of gravitational forces in galaxies and galactic
clusters is usually referred as the existence of "dark matter particles"
of unknown origin. An alternative explanation of the dark matter effect
is presented here by assuming that the empty space of the Universe has a
complicated geometrical structure. It is assumed that the cosmological
Lambda term, which is approximately constant at scales of several Mpc
and describes the dark energy, is not constant at scales of several
tenth of Kpc and describes the "dark matter effect". This term is
mathematically analogous, but not identical, with the energy-momentum
tensor of particles ensembles. In this connection the general expression
of the Riemann tensor, which depends on the matter distribution in space
and on the empty space geometry, is considered. The Ricci tensor does
not describe all possible empty space structures. The tensor of the spin
curvature also has to be taken into account. Local deviations of the
empty space geometry of Universe from a flat one provide the same
observational effect as clouds of invisible particles which demonstrate
themselves by their gravitational fields only. The matter, which forms
stars and galaxies, will concentrate in gravitational depressions of
empty space. The gravitation provides correlation of the luminous matter
distribution and geometrical structures of space. The presented theory
is compared with observations.
Eric Flesch
>Again, this seems very ad-hoc to me. Note that the OP asked about
>CREDIBLE alternative theories.
The gravitational depressions, if like mine, caters for galaxy
rotational profiles and ambient stellar mixing in elliptical galaxies
and globular star clusters. Lobes and jets can be easily explained if
they are simply falling out of the galaxy.
If you go out to sea, you are always facing eddies & currents, not the
smooth surface you saw from land. Why not the same in space, where
the surface of the 4th large dimension could act as the surface of the
sea.
eric gisse
@hydra.herts.ac.uk:
eric gisse
@hydra.herts.ac.uk:
matter, or much of anything else.
"It is assumed that the cosmological L term, which is pproximately
is not constant at scales of several tenth of Kpc and describes
the “dark matter effect”."
"This term is mathematically analogous, but not identical, with
the energy-momentum tensor of particles ensembles."
stress tensor of a perfect fluid with the cosmological constant.
"The Ricci tensor does not describe all possible empty space
structures."
"The tensor of the spin curvature also has to be taken into
account."
in Einstein-Cartan theory, direct contributions from angular momentum
are not relevant even at an extremal black hole so still "no".
"The matter, which forms stars and galaxies, will
concentrate in gravitational depressions of empty space."
ranging and the Nordtelvdt effect.
<skimming further looking for additional nonsense>
"Gravitational fields of particles ensemble are determined by the
energy momentum tensors T_ik of the ensemble. However, particles
interact with each other not only by gravitation, but also by
other forces and the knowledge of T_ik is not enough to describe
the ensemble."
He does not understand that the stress tensor actually does include
this. Oh well. Enough of this.
Who lets these people post to arXiv?
Phillip Helbig---undress to reply
Essentially anyone can post to arXiv. Obvious cranks who try too often
have their papers moved to a "general" section, which is a euphemism for
"rubbish". However, individual papers are not, as a rule, screened in
any way.
Eric Flesch
>Gravitational energy itself gravitates, the idea is DOA as per lunar
>ranging and the Nordtelvdt effect.
abuse of the term "energy"? The Nordtvedt effect has not been
observed, which is consistent with gravity not gravitating. Gravity
has never been observed to gravitate.
Jonathan Thornburg [remove -animal to reply]
[[about an idea the details of which aren't relevant to the points I
want to make here]]
>ranging and the Nordtelvdt effect.
> Sorry, that's nonsense. What's "gravitational energy", other than an
> abuse of the term "energy"? The Nordtvedt effect has not been
> observed, which is consistent with gravity not gravitating. Gravity
> has never been observed to gravitate.
that's so interesting about the Nordtvedt is precisely that it's *not*
observed -- which is very strong evidence that gravitational energy
*does* itself gravitate (just like other forms of mass-energy).
To explain this in more detail, let me start with some background on
the gravitational interaction of *electromagnetic* binding energy:
Suppose we have a pair of test masses held apart by a light strut,
surrounded by a Faraday cage to screen them from external electromagnetic
fields. We can investigate the gravitational force between this
composite body and the Earth by dropping our pair-of-test-masses and
seeing how fast it free-falls in the Earth's gravitational field.
Now suppose we put a + electrical charge on each of those test masses.
Thanks to the Faraday cage, there won't be any electromagnetic
interactions between the charges and the outside-the-Faraday-cage world.
But the individual + charges repel each other, we had to do work on
the initial uncharged-pair-of-test-masses system to get those charges
onto the test masses. By conservation of energy energy the rest mass
of the charged-pair-of-test-masses system is thus slightly larger than
that of the uncharged-pair-of-test-masses. If we now drop the
charged-pair-of-test-masses, how fast does it free-fall in the
Earth's gravitational field?
Experimentally, the answer is "at the same rate as the
uncharge-pair-of-test-masses".
[Actual Eotvos experiments are done a bit differently:
they exploit the electromagnetic binding energy of the
different charged subatomic particles within the atoms
making up a laboratory test mass, and the small differences
from one chemical element to another in the fractional
amount of such electromagneitc binding energy. But for
our purposes here, that's equivalent to the Gedanken
experiment I just described.]
Since the charged-pair-of-test-masses system has a larger rest mass
than the uncharged-pair-of-test-masses system, achieving the same
free-fall acceleration must (by Newton's 2nd law) mean that a
correspondingly larger gravitational force must have been exerted
by the Earth on the charged-pair-of-test-masses system than on the
uncharged-pair-of-test-masses system.
In other words, this experiment demonstrates that electromagnetic
binding energy gravitates just like other forms of mass-energy.
Now let's consider the Nordtvedt effect: Here we're considering an
experiment analogous to the above one, but applied to *gravitational*
binding energy. That is, we want to compare the free-fall acceleration
of two bodies in an external gravitational field, where the two bodies
have different fractions of their rest masses made up of (Newtonian)
gravitational binding energy.
For the actual experiment (first analyzed by Kenneth Nordtvedt, thus
the name), the two test bodies are the Earth and the Moon, free-falling
in the Sun's gravitational field. The Earth has approximately -4.6e-10
of its rest mass comprised of gravitational binding energy,
[the sign is negative because gravity is *attractive*,
so the gravitational binding *reduces* the overall
rest-mass of the Earth below that of all its individual
atoms placed far apart]
while for the moon this fraction is approximately -0.2e-10. Nordtvedt
showed that *if* gravitational binding energy did *not* gravitate just
like other forms of mass-energy, there would be a measurable time-
-variation (the "Nordtvedt effect") in the Earth-Moon distance, of
typical amplitude on the order of 8 meters.
Observationally, this variation is *not* present, with current
observational error bars (from analysis of lunar-laser-ranging data)
of much less than a centimeter. In other words, the Nordtvedt effect
*doesn't* occure in nature, i.e., the Earth's and Moon's gravitational
binding energies do indeed gravitate just like other forms of mass-energy.
This is precisely what general relativity's equivalence principle
predicts. Other Gravity theories of the form "gravity is some sort of
spin-2 field on a flat background" usually predict that gravitational
binding energy *doesn't* gravitate, i.e., they predict that the
Nordtvedt effect *should* be present. The non-occurence of the
Nordtvedt effect thus refutes such theories.
--
-- "Jonathan Thornburg [remove -animal to reply]" <jth...@astro.indiana-zebra.edu>
Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
"Washing one's hands of the conflict between the powerful and the
powerless means to side with the powerful, not to be neutral."
-- quote by Freire / poster by Oxfam
eric gisse
@hydra.herts.ac.uk:
> On Sun, 30 Oct 11, eric gisse <jowr.pi...@gmail.com> wrote:
>>Gravitational energy itself gravitates, the idea is DOA as per lunar
>>ranging and the Nordtelvdt effect.
>
> Sorry, that's nonsense. What's "gravitational energy", other than an
> abuse of the term "energy"?
in a bound state than two particles far away.
Since my point was clearly missed, I'll expand:
Energy that would generate that depression would itself gravitate and we'd
see it through say the Integrated Sachs-Wolfe effect. Or in actuality we'd
simply have reverse dark matter: too much gravitation for what we see.
> The Nordtvedt effect has not been
> observed, which is consistent with gravity not gravitating. Gravity
> has never been observed to gravitate.
>
understand the subject. If you have a non-null Nordtevdt effect it means
gravitational energy doesn't quite gravitate according to what GR predicts.
We have repeatedly observed the effects of binding energy on lunar ranging,
and stuff like hyperbound objects (white dawrf to neutron star, extremal
case being the black hole) would not behave as we expect were that the
case.
eric gisse
news:mt2.0-19102...@hydra.herts.ac.uk:
[...correct stuff...]
> This is precisely what general relativity's equivalence principle
> predicts. Other Gravity theories of the form "gravity is some sort of
> spin-2 field on a flat background" usually predict that gravitational
> binding energy *doesn't* gravitate, i.e., they predict that the
> Nordtvedt effect *should* be present. The non-occurence of the
> Nordtvedt effect thus refutes such theories.
>
(disregarding the source of it for the moment) and don't deal with the fact
that the energy will play hell with the binding of your system, then your
theory is DOA.
This might seem trivial or irrelevant, but measuring the binding energy on
things like galactic superclusters is also a huge test of dark energy
because on that scale the binding energy of the structure is significantly
altered.
Eric Flesch
>Eric Gisse is right here, and Eric Flesch is mistaken: The thing
>that's so interesting about the Nordtvedt is precisely that it's *not*
>observed -- which is very strong evidence that gravitational energy
>*does* itself gravitate (just like other forms of mass-energy).
and check some things. But whilst I appear to be out-gunned here,
I'll just lay out a few simple thoughts:
(1) If "gravity gravitates", that should be translatable into a simple
adjustment on the inverse square law, which hasn't been observed.
(2) The Nordtvedt experiment is meant as a test on whether "inertia"
gravitates, using the equivalence principle. That the test turns out
negative does not, to my thinking, show that "gravity gravitates"
because the alternative explanation is that the "inertial energy"
concept, ie, "gravitational energy", is false. In other words, the
negative Nordtvedt result shows that either both paradigms of "gravity
gravitates" and "gravitational energy" are right or wrong in tandem.
My stance is that they are both wrong. Your stance is that they are
both right. Either way the Nordtvedt result is negative.
The germane saying is "things should be made as simple as possible,
but no simpler". My interpretation is simpler.
Perhaps I should simply stay out of such topics because my expertise
is not up to yours. But when I see unnecessary complexities, it is
like a red flag to an old bull; I still remember.
Eric Flesch
eric gisse
@hydra.herts.ac.uk:
> On Sun, 30 Oct 11"Jonathan Thornburg wrote:
>>Eric Gisse is right here, and Eric Flesch is mistaken: The thing
>>that's so interesting about the Nordtvedt is precisely that it's *not*
>>observed -- which is very strong evidence that gravitational energy
>>*does* itself gravitate (just like other forms of mass-energy).
>
> Thanks for the interesting post which I will mull over for a few days
> and check some things. But whilst I appear to be out-gunned here,
> I'll just lay out a few simple thoughts:
>
> (1) If "gravity gravitates", that should be translatable into a simple
> adjustment on the inverse square law, which hasn't been observed.
generates it, I am unclear on how you think that'd alter the inverse
square law. Besides, GR already does that - see the mathematical
description of perihelion advance which kicks in a small k/r^2 term to
the potential.
>
> (2) The Nordtvedt experiment is meant as a test on whether "inertia"
> gravitates, using the equivalence principle. That the test turns out
> negative does not, to my thinking, show that "gravity gravitates"
> because the alternative explanation is that the "inertial energy"
> concept, ie, "gravitational energy", is false. In other words, the
> negative Nordtvedt result shows that either both paradigms of "gravity
> gravitates" and "gravitational energy" are right or wrong in tandem.
> My stance is that they are both wrong. Your stance is that they are
> both right. Either way the Nordtvedt result is negative.
Two objects at a distance have less energy than two objects stuck
together. The energy of being clumpted together itself has gravitational
influence, which makes gravitation stronger....which repeats itself
until you are tired of including additioanl contributions from self-
feedback.
>
> The germane saying is "things should be made as simple as possible,
> but no simpler". My interpretation is simpler.
>
> Perhaps I should simply stay out of such topics because my expertise
> is not up to yours. But when I see unnecessary complexities, it is
> like a red flag to an old bull; I still remember.
>
> Eric Flesch
>
however nobody will take you seriously when you complain about them.
http://relativity.livingreviews.org/Articles/lrr-2006-3/
Go read the equivalence principle tests. It'll be useful.
Eric Flesch
>Eric Flesch <er...@flesch.org> wrote
>> gravitates, using the equivalence principle.
for me to take him trick-or-treating, so I wrote that in a hurry.
What I meant is clear, Nordtvedt was testing the attributes of
so-called "gravitational energy",
>> Perhaps I should simply stay out of such topics because my expertise
>> is not up to yours. But when I see unnecessary complexities, it is
>> like a red flag to an old bull; I still remember.
>
>however nobody will take you seriously when you complain about them.
interpretation of the negative outcome is that the whole concept is
bunkum. Occam and me, we're pals.
>http://relativity.livingreviews.org/Articles/lrr-2006-3/
>
>Go read the equivalence principle tests. It'll be useful.
Jonathan Thornburg [remove -animal to reply]
> (2) The Nordtvedt experiment is meant as a test on whether "inertia"
> gravitates, using the equivalence principle. That the test turns out
> negative does not, to my thinking, show that "gravity gravitates"
> because the alternative explanation is that the "inertial energy"
> concept, ie, "gravitational energy", is false. In other words, the
> negative Nordtvedt result shows that either both paradigms of "gravity
> gravitates" and "gravitational energy" are right or wrong in tandem.
> My stance is that they are both wrong.
have inertia] is that it's hard to reconcile with conservation of
momentum.
[If you want to abandon conservation of momentum,
note that since momentum and energy are components
of the *same* 4-vector, that means that in other
reference frames, you have violations of conservation
of energy, i.e., you can build a (gedanken)
perpetual-motion machine. :( ]
That is, let's start by considering a (gedanken) apparatus (for later
use we'll call it "apparatus A") containing a pair of masses, a mechanical
linkage which lets them move with respect to each other, an electric
motor/generator hooked up to that linkage, and finally a small particle
accelerator which can make matter-antimatter particle pairs if you feed
it with electricity. And finally let's have a pair of reservoirs to
hold (respectively the matter and the antimatter, and some (gedanken)
perfectly efficient solar cells to catch any gamma rays that would
result if we let the matter & antimatter annihilate each other.
Start with the two test masses some distance apart, and the matter
and antimatter reservoirs empty. Let's call this configuration of
apparatus A "configuration #1", and let's call apparatus A's total
rest mass-energy (as operationally defined by Newton's 2nd law)
in this configuration, "M". That is, M is a measure of the inertia
of apparatus A in configuration #1.
Now let the two test masses fall towards each other, under the influence
of their (Newtonian) mutual gravitational attraction. This releases
some gravitational binding energy E which we can harvest as electricity
using the electric motor/generator. We use this electricity to run the
particle accelerator, making a mass (split 50/50 between matter and
antimatter so there's no problem with conservation of electric charge)
E/c^2, which is stored in the reservoirs. Let's call this configuration
of apparatus A (masses close together, plus some matter/antimatter),
"configuration #2". Since (following our hypothesis that gravitational
binding energy has no inertia) the two masses have the same inertia
they had before, the total rest mass-energy [again operationally
defined via Newton's 2nd law] of apparatus A in configuration #2, i.e.,
now including the newly-manufactured matter & antimatter, is M + E/c^2.
So, what we have is some apparatus which can change its inertia (i.e.,
its mass-as-defined-by-Newton's-2nd-law) between that of a mass M
(when the apparatus is in configuration #1), and that of a mass M + E/c^2
(when the apparatus is in configuration #2).
And (gedanken) it's easy to reverse this process, annihilating the
matter & antimatter to get energy, then using this via the electric
motor to pull the two masses apart from each other, returning the
apparatus to configuration #1.
To actually get a violation of conservation-of-momentum with this, we
need a bit more (gedanken) apparatus: We now place apparatus A in a
long and moderately massive tube so apparatus A can move freely back
and forth with respect to the tube. And we put (perfect, frictionless)
springs at each end of the tube, and we set apparatus A bouncing back
and forth in the tube.
Conservation of momentum implies that when apparatus A is moving to
the right, the tube is moving to the left (in a referece frame where
the center-of-mass of the whole apparatus-A-plus-tube is stationary).
But now what happens if we have apparatus A change its inertia while
it's in flight? Let's say we have it be in the low-inertia state
(configuration #1) each time it's moving left and about to bounce off
the tube's left end-spring, and then transition to the high-inertia
state (configuration #2) when it's moving right and about to bounce
off the tube's right end-spring.
It's easy to see that after one complete left-right cycle the whole
system (tube + apparatus A) will now have acquired a net linear
momentum to the right, and with each complete cycle it will acquire
further such momentum.
That is, we've just built a "reactionless space drive", i.e., we've
violated conservation of momentum. [And as I noted above, an observer
watching this whole process from a moving reference frame would also
see violations of conservation of energy, i.e., she would say that
we've also built a perpetual-motion machine.]
In conclusion, then, while it's certainly _possible_ that gravitational
binding energy neither gravitates nor has inertia, that would imply
that neither energy nor momentum are conserved. Most physicists would
prefer to keep energy/momentum conservation, and correspondingly argue
that gravitational energy *both* gravitates *and* has inertia.
Fortunately, we should quite direct experimental evidence bearing on
this point within about 5 years: When advanced LIGO and Virgo are
operational (roughly 2015-2016), they should detect gravitational
waves from (among other sources) binary neutron star coalescences
and black hole - neutron star coalescences. If gravitational binding
energy (which is on the order of 10% to 20% of the total rest mass
for a neutron star) were "invisible" to both inertia and gravitation,
I would expect this to have significant effects on the gravitational
radiation waveforms.
ciao,
Jos Bergervoet
> Eric Flesch <e...@flesch.org> wrote in news:mt2.0-14899-1319988383
...
..
>
> Energy that would generate that depression would itself gravitate and we'd
> see it through say the Integrated Sachs-Wolfe effect. Or in actuality we'd
> simply have reverse dark matter: too much gravitation for what we see.
of gravitation, wouldn't that require just dark matter? Why reverse?
>> The Nordtvedt effect has not been
>> observed, which is consistent with gravity not gravitating. Gravity
>> has never been observed to gravitate.
>>
>
> The Nordtevdt effect is fantastic additionally for testing whether a person
> understand the subject. If you have a non-null Nordtevdt effect it means
> gravitational energy doesn't quite gravitate according to what GR predicts.
it..)
--
Jos
eric gisse
news:mt2.0-22770...@hydra.herts.ac.uk:
> On Oct 30, 11:45�pm, eric gisse <jowr.pi.ons...@gmail.com> wrote:
>> Eric Flesch <e...@flesch.org> wrote in news:mt2.0-14899-1319988383
> ...
> ..
>> Since my point was clearly missed, I'll expand:
>>
>> Energy that would generate that depression would itself gravitate and
>> we'd see it through say the Integrated Sachs-Wolfe effect. Or in
>> actuality we'd simply have reverse dark matter: too much gravitation
>> for what we see.
>
> This is confusing. If we do not see enough to explain some amount
> of gravitation, wouldn't that require just dark matter? Why reverse?
The energy of the depression would itself be gravitating and would be an
additional source of gravitation so if this napkin-scribble of a theory
were correct we would see an abundance of gravitation for what see see
rather than a deficit.
>
>>> The Nordtvedt effect has not been
>>> observed, which is consistent with gravity not gravitating. Gravity
>>> has never been observed to gravitate.
>>>
>>
>> The Nordtevdt effect is fantastic additionally for testing whether a
>> person understand the subject. If you have a non-null Nordtevdt
>> effect it means gravitational energy doesn't quite gravitate
>> according to what GR predicts.
>
> Or maybe some dark matter distribution interferes? (Since we're at
> it..)
>
> --
> Jos
>
those who think I'm just pressing buttons and making things up.
Jos Bergervoet
> Jos Bergervoet <jos.r.bergerv...@gmail.com> wrote innews:mt2.0-22770...@hydra.herts.ac.uk:
..
...
>>> for what we see.
>
>> This is confusing. If we do not see enough to explain some amount
>> of gravitation, wouldn't that require just dark matter? Why reverse?
>
> The answer to this question requires reading what I wrote.
Dark matter: too much gravitation for what we see.
What you wrote was in fact creating the question..
--
Jos
Eric Flesch
>My stance is that they are both wrong.
And what I see is a house of cards. Basically if we start with the
axioms of matter-energy and a flat 3-manifold, then we end up,
fractally, with notions of gravity gravitating etc.
My point is that by adjusting the axioms, we can get a simpler
outcome. No, I don't have the solution, but I know a skunk when I
smell it.
JT's gedankens basically say that I would have a gedanken
perpetual-motion machine because other gedankens (perfect springs,
etc) could be used to make one, given my intitial stance. But if you
need X to make X, then you have not truly made X. So I think JT's
gedankens do not prove his point.
On that note, I'll bow out of this discussion, because I don't have
the breakthrough. But if you read the literature of 100 years ago,
you'll be struck by how many ladders were leaning against the wrong
walls then. Guess what, today is no different.
cheers, Eric
eric gisse
@hydra.herts.ac.uk:
>
> And what I see is a house of cards. Basically if we start with the
> axioms of matter-energy and a flat 3-manifold, then we end up,
> fractally, with notions of gravity gravitating etc.
fact that everything you wrote after that was nonsense?
The full Einstein field equations are nonlinear by their very nature.
You can even see this when trying to create first order solutions while
demanding the stress tensor be divergence free, in that you can't do it
without including higher order contributions...
>
> My point is that by adjusting the axioms, we can get a simpler
> outcome. No, I don't have the solution, but I know a skunk when I
> smell it.
when presented with an aspect of it you don't like you think it stinks?
Is this really sci.astro.research?
There is no axiom to 'adjust'. This is a fundamental consequence of the
strong equivalence principle. Change that and you don't have relativity
anymore.
>
> JT's gedankens basically say that I would have a gedanken
> perpetual-motion machine because other gedankens (perfect springs,
> etc) could be used to make one, given my intitial stance. But if you
> need X to make X, then you have not truly made X. So I think JT's
> gedankens do not prove his point.
Could you elaborate on how you feel you could turn gravitational binding
energy into perpetual motion?
The laws of thermodynamics and conservation of energy (when the concept
exist and are relevant) both apply in general relativity.
>
> On that note, I'll bow out of this discussion, because I don't have
> the breakthrough. But if you read the literature of 100 years ago,
> you'll be struck by how many ladders were leaning against the wrong
> walls then. Guess what, today is no different.
>
> cheers, Eric
Hold on now.
If you are going to make a bunch of ridiculous statements then leave the
discussion, why make the ridiculous statements at all?
Eric Flesch
>If you are going to make a bunch of ridiculous statements then leave the
>discussion, why make the ridiculous statements at all?
>Let me get this straight. You do not understand general relativity ...
False.
>Do you think the 'house of cards' comment have anything to do with the
>fact that everything you wrote after that was nonsense?
But wait, let's bring out a real topic from a previous post: I wrote:
>> (1) If "gravity gravitates", that should be translatable into a simple
>> adjustment on the inverse square law, which hasn't been observed.
>
>generates it, I am unclear on how you think that'd alter the inverse
>square law.
energy" presumably not separable from the source matter. But of
course gravity acts at a distance. If "gravity gravitates", then this
extra gravitating would act across the whole gravitational field. So
the inverse square law would be adjusted. If you say gravity
at-a-distance does not gravitate, but gravity does gravitate, then it
is you who are being unclear.
Now I really have no more time to chase my tail (or yours) on this,
but it is not for the reasons that you say.
EF