I read the following somewhere:
"An alternative way to conceive of gravity
would of course be to follow the lead of
other theories, and regard the gravitational
field as simply a distribution of properties
(the field strenghts) in flat spacetime.
What ultimately makes this unattractive
is that the distinctive properties of this
spacetime would be completely unobservable,
because all matter and fields gravitate. In
particular, light rays would not lie on the "light
cone" in a flat spacetime, once one incorporated
the influence of gravity. It was ultimately the
unobservability of the inertial structure of
Minkowski space that led Einstein to eliminate it
from his theory of gravitation and embrace the
geometric approach."
Questions.
1. Is gravity in flat spacetime means the same as
force based gravity or is force based gravity another
method where there is no spacetime but fixed space
and time? If so, this means gravity in flat spacetime
is fields based gravity in contrast to force based gravity?
2. How come light rays won't lie on the "light
cone" in a flat spacetime gravity theory?
3. What is meant by the "unobservability of the inertial structure of
Minkowski" that makes impossible gravity based on
flat spacetime?
4. Is it totally impossible to model gravity that is not
based on spacetime curvature? Maybe there is
another way like perhaps the flat spacetime floating
in brane surface, etc. What can you think of or
maybe some creative folks have thought of it (pls.
share it)?
tnx.
ralph
Yes.
If so, this means gravity in flat spacetime
: is fields based gravity in contrast to force based gravity?
No.
:
: 2. How come light rays won't lie on the "light
: cone" in a flat spacetime gravity theory?
Yes.
:
: 3. What is meant by the "unobservability of the inertial structure of
: Minkowski" that makes impossible gravity based on
: flat spacetime?
Yes.
:
: 4. Is it totally impossible to model gravity that is not
: based on spacetime curvature?
Yes.
Maybe there is
: another way like perhaps the flat spacetime floating
: in brane surface, etc. What can you think of or
: maybe some creative folks have thought of it (pls.
: share it)?
No.
: tnx.
Idiot.
Of course it is possible eg string theory.
>
> I read the following somewhere:
>
> "An alternative way to conceive of gravity
> would of course be to follow the lead of
> other theories, and regard the gravitational
> field as simply a distribution of properties
> (the field strenghts) in flat spacetime.
> What ultimately makes this unattractive
> is that the distinctive properties of this
> spacetime would be completely unobservable,
> because all matter and fields gravitate. In
> particular, light rays would not lie on the "light
> cone" in a flat spacetime, once one incorporated
> the influence of gravity. It was ultimately the
> unobservability of the inertial structure of
> Minkowski space that led Einstein to eliminate it
> from his theory of gravitation and embrace the
> geometric approach."
>
> Questions.
>
> 1. Is gravity in flat spacetime means the same as
> force based gravity or is force based gravity another
> method where there is no spacetime but fixed space
> and time? If so, this means gravity in flat spacetime
> is fields based gravity in contrast to force based gravity?
Gravity in flat space-time , otherwise known as linaerised gravity, is
easily constructed based on EM - See Ohanian and Ruffini - Gravitaiton and
Sapce-time. Trouble it it cotnains the seeds of its own destrcution. It
can be shown that particles moves as is space-time had an infenstisimal
curvature and its guage invarience is infintesimal coordinate
transformation. The obvious conseqeuince leads immedtly to GR.
>
> 2. How come light rays won't lie on the "light
> cone" in a flat spacetime gravity theory?
If you mean what I hope you mean it is because it has an in infinitesimal
curvature. In not then you probably don't know enough to ask a sensible
question.
>
> 3. What is meant by the "unobservability of the inertial structure of
> Minkowski" that makes impossible gravity based on
> flat spacetime?
I have no idea what you are talking about.
>
> 4. Is it totally impossible to model gravity that is not
> based on spacetime curvature?
As stated above of course not.
Bill
But in string theory, spacetime still has curvature. Superspring
theory just quantizes a classical "string theory" and yet has
General Relativity as a low-energy limit. If you don't agree.
Are you implying that in string and superstring theory,
spacetime is flat and what caused gravity are gravitons?
But how does this differ to the gravity as fields aspect of
flat spacetime which is deemed unfeasible (take note
that gravitons as particles and fields are related as in the
QFT programme).
Why. What would happen to light rays if it passes thru infinitesimal
(extremely small) curvature and what's the cause of that curvature?
Any public papers by them?
>
>
>
> > 3. What is meant by the "unobservability of the inertial structure of
> > Minkowski" that makes impossible gravity based on
> > flat spacetime?
>
> I have no idea what you are talking about.
Steven Weinstein mentioned it.
>
>
>
> > 4. Is it totally impossible to model gravity that is not
> > based on spacetime curvature?
>
> As stated above of course not.
As explained above in string and superstring theory, spacetime
is still curved.
ralph
>
> Bill
>
>
>
> > Maybe there is
> > another way like perhaps the flat spacetime floating
> > in brane surface, etc. What can you think of or
> > maybe some creative folks have thought of it (pls.
> > share it)?
>
> > tnx.
>
> > ralph- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
>
> - Show quoted text -
> Is it really impossible with no chance that gravity can
> be modeled non-geometrically (as curvature)??
>
> I read the following somewhere:
>
> "An alternative way to conceive of gravity
> would of course be to follow the lead of
> other theories, and regard the gravitational
> field as simply a distribution of properties
> (the field strenghts) in flat spacetime.
> What ultimately makes this unattractive
> is that the distinctive properties of this
> spacetime would be completely unobservable,
> because all matter and fields gravitate. In
> particular, light rays would not lie on the "light
> cone" in a flat spacetime, once one incorporated
> the influence of gravity. It was ultimately the
> unobservability of the inertial structure of
> Minkowski space that led Einstein to eliminate it
> from his theory of gravitation and embrace the
> geometric approach."
It is not necessary to assume an interaction with
light and gravity, working with the full Maxwell fields.
Light doesn't interact with light. Eh ?
>
> Questions.
>
> 1. Is gravity in flat spacetime means the same as
> force based gravity or is force based gravity another
> method where there is no spacetime but fixed space
> and time? If so, this means gravity in flat spacetime
> is fields based gravity in contrast to force based gravity?
>
> 2. How come light rays won't lie on the "light
> cone" in a flat spacetime gravity theory?
Because the light cone is imaginary?
>
> 3. What is meant by the "unobservability of the inertial structure of
> Minkowski" that makes impossible gravity based on
> flat spacetime?
I would question the validity of the statement. Einstein had
a penchant for eliminating structures from equations, even
where known. For example, a little hydrogen gas and
some elementary antenna theory resolves SR's postulates
without conflict. On the plus side, his approach gives some
microatomic utility where structure is unknown.
>
> 4. Is it totally impossible to model gravity that is not
> based on spacetime curvature? Maybe there is
> another way like perhaps the flat spacetime floating
> in brane surface, etc. What can you think of or
> maybe some creative folks have thought of it (pls.
> share it)?
Straight lines are for a mathematician's convenience
not for nature's convenience.
If a billiard table were strewn with 1/2 attractive balls
and 1/2 repulsive balls, you would think someone
crazy that claimed a cue ball could follow a stratight
trajectrory from one end of the table to the other. Eh?
The flux lines in the most fundamental attractor (e+,e-)
are curved:
http://web.mit.edu/8.02t/www/802TEAL3D/visualizations/electrostatics/thumbnails/dipFieldThumb.jpg
If you want an approximate *mechanism* that yields
straight-line forces you can consider a toy model like:
http://www.mypage.bluewin.ch/Bizarre/GRAV.htm
or integrate the straight-line forces with Ewald sums
to show that it works:
http://www.research.ibm.com/grape/grape_ewald.htm
(don't try this on the back of an envelope) :o)
If you want a *formalism* that relates gravity and inertia
you have GR.
http://nobelprize.org/nobel_prizes/physics/laureates/1921/einstein-lecture.html
<<The element, T_ , of the energy momentum tensor represents
the flux of the th-component of the
*** four-momentum ***
[
http://en.wikipedia.org/wiki/Four-momentum
http://farside.ph.utexas.edu/teaching/em/lectures/node126.html
]
of the electromagnetic field,P , going through a hyperplane x =
constant. It represents the contribution of electromagnetism
to the source of the gravitational field (curvature of space-time)
in general relativity. >>
http://en.wikipedia.org/wiki/Electromagnetic_stress-energy_tensor
http://en.wikipedia.org/wiki/Stress-energy_tensor
http://www.physics.ucla.edu/~cwp/articles/noether.asg/noether.html
Sue...
The only thing which makes it possible to model gravity as
spacetime curvature is the equivalence principle which states
that inertial mass and gravitational mass are the same. If
that happened to be false, then gravity would have to be
modeled some other way. If it is true, then any other model
of gravity would have to appear exactly likle spacetime curvature,
in which case, what would be gained by assuming spacetime is
flat, having to explain why spacetime is flat and inventing a
force to make it appear curved? The most natural assumption is
that spacetime is what it is, whether that means flat or not.
If physical measurements tell us spacetime is curved, then
it's curved.
Sue. As being the most intelligent of all crackpots. Pls. show how
inertial mass
and gravitational mass can be the same and yet GR is false. How then
is gravity caused? by force? how?
ralph
Gravity need not be the curvature of spacetime. There are many
relativistic non-instantaneous action-at-a-distance theories.
http://cat.inist.fr/?aModele=afficheN&cpsidt=17417473
http://arxiv.org/abs/hep-th/0510193
http://prola.aps.org/abstract/PRD/v15/i12/p3597_1
http://www.univ-nancy2.fr/DepPhilo/walter/papers/b4.pdf
Shubee
http://www.everythingimportant.org/relativity/special.pdf
Do you know the reason why energy-momentum can curve
spacetime? One is a quantum field, the other one (spacetime)
is a manifold without any content (pure geometry). How do they
communicate with one another?
ralph
The devices that measure motor fuel are false at most
temperatures. That doesn't prevent you and a retailer
from transacting honest business does it?
The retailer can install temperature correction if warranted
A GR theorist can implemement other solutions to the
field equations if warranted.
> How then
> is gravity caused? by force? how?
If you can accept that Coulomb force is magic this
is a *plausible mechanism* for attractive neutrally
charged bodies"
http://www.chem.purdue.edu/gchelp/liquids/inddip.html
Here it is developed for long-ranges:
http://arxiv.org/abs/physics/0107015 pdf
http://www.mypage.bluewin.ch/Bizarre/GRAV.htm
It has more flaws than
GR because GR can make predictions that are
testable. That is the final arbiter of a scientific
theory and you wouldn't want it any other way.
Has some well intentioned GR advocate convinced you
that *force* is a dirry word? It isn't. The theory has its
basis in inertial trajectories so it is just difficult to
get to the force terms and they may be unreliable.
Classical mechanics pops out for most of the things
we can test in this solar system so unweildly force
terms are seldom a problem.
Sue...
>
> ralph- Hide quoted text -
>4. Is it totally impossible to model gravity that is not
>based on spacetime curvature? Maybe there is
>another way like perhaps the flat spacetime floating
>in brane surface, etc. What can you think of or
>maybe some creative folks have thought of it (pls.
>share it)?
>
Creative, but controversial:
Quantum-Foam, Gravity and Gravitational Waves
http://www.scieng.flinders.edu.au/cpes/people/cahill_r/HPS16.pdf
http://www.scieng.flinders.edu.au/cpes/people/cahill_r/processphysics.html
----------------
IMHO
there i s no gravity
not any attraction force with
messengers tha tmove in straight lines!
it must be by messengers that move
in curved lines and atatck the attracted
objet from its rare side
in a system that enaables
an unbalanced force biased to
more and more close the distance
betwen objects
ATB
Y.Porat
------------------
When one begins to study Quantum Gravity. One can go nuts.
Note quantum gravity is not just about physics of the planck
scale but quantum gravity is about space, time and matter
which is a fundamental reality.
ralph
However, that would be, for instantance, a roughly the same as an effect
along a massive object as the Sun has on a spacetime, along which, it would
stretche and curve, as in the meantime, when you would try to roll an object
across a sheet, it would try to move along a straight line as required along
the motion, but along a massive object it would rolls down to the more
massive object.
Therefore, along that matter, this is a gravity, which is a definitely a
simple product along a bending of a spacetime, all along, and this is what
is all about, a definitely as a matter a fact.
--
Ahmed Ouahi, Architect
Best Regards!
"Ralph" <ralpht...@yahoo.com> wrote in message
news:1183854107.1...@d30g2000prg.googlegroups.com...
>
The above is basic and just garden variety general relativity. What
we must figure out is what really is space, what really is time.. and
what are their intrinsic relationship to matter (especially quantum
fields).
The answer to it is the solution to quantum gravity or the
fundamental
truth about space, time, matter and energy.
ralph
> --
> Ahmed Ouahi, Architect
> Best Regards!
>
> "Ralph" <ralphtwar...@yahoo.com> wrote in message
> > ralph- Hide quoted text -
--
> The above is basic and just garden variety general relativity. What
> we must figure out is what really is space, what really is time.. and
> what are their intrinsic relationship to matter (especially quantum
> fields).
That is easy.
Space is really hydrogen.
"Propagation in a dielectric medium"
http://farside.ph.utexas.edu/teaching/em/lectures/node98.html
http://en.wikipedia.org/wiki/Free_space
http://www-ssg.sr.unh.edu/ism/what.html
Time is really the extra fuel in the tank of
the loosing car in a drag race.
http://en.wikipedia.org/wiki/Noether's_theorem
http://www.physics.ucla.edu/~cwp/articles/noether.asg/noether.html
Quantum field is really...ahh ahhh..
Well... two out three isn't bad and who want to use
an evil theory that might be killing a cute little kitty cat
every time its state is uncertain. :o)
Sue...
> > - Show quoted text -- Hide quoted text -
The same reason that the energy-momentum tensor would ``flatten''
spacetime. Don't assume spacetime has any prior geometry and then
your question is, ``why should spacetime be anything?'' If you assume
spacetime is flat, you've skipped the question general relativity
addresses which is the reason you are asking the question above.
> One is a quantum field, the other one (spacetime)
> is a manifold without any content (pure geometry). How do they
> communicate with one another?
I'm not sure why you think geometry has no content. In particular,
newtonian mechanics follows from assuming the geometry of galilean
spacetime, special relativity follows from assuming the geometry of
minkowski space and general relativity follows from assuming no prior
geometry and attributing the geometry itself (whatever that may be)
to the energy-momentum tensor. That would seem to be a great deal of
content, especially since general relativity explains what you would
otherwise have to assume.
: When one begins to study Quantum Gravity. One can go nuts.
You've proved that already.
: Note quantum gravity is not just about physics of the planck
: scale but quantum gravity is about space, time and matter
: which is a fundamental reality.
Fundamental reality is falling off a cliff whatever your crackpot
theories say.
Idiot.
Therefore, as it has had been the matter, which it has had makes -space- its
existence, as it has had been along the human thought, and the needs,
consciouslly or unconconsciouslly, which also has makes the existence of a
time, especially, when they have had started its counting as a product,
along which to make a products, for their own existence, and the ultimate
relation along the all, is that the one does not exist as does not move
without the other, and this is the basic, and what is all about, a
definitely as a matter.
--
Ahmed Ouahi, Architect
Best Regards!
"Ralph" <ralpht...@yahoo.com> wrote in message
news:1183904861.9...@d30g2000prg.googlegroups.com...
----------
if you waht totake my advice :
dont waist your precious tme on GR
and not on quantum gravity
it is dead by arival
ATB
Y.Porat
----------------
Not sure what you mean. What that paragraph is talking about is not a
different theory of gravity, just general relativity described in a
different way. The idea is that instead of working with g_uv, you fix a
coordinate system and work with h_uv = g_uv - eta_uv, where eta_uv is the
Minkowski metric. You can get field equations for this, which describe a
sort of dynamical field filling Minkowski space. But at the end of the day,
the Minkowski-space part of it is useless, because nothing moves according
to the Minkowski metric. Contrast this with electrodynamics, where there are
uncharged particles that don't see the field and do move according to the
underlying Minkowski geometry.
(Technically this is not quite the same as general relativity, since it
doesn't allow for topologically nontrivial geometries, while "real" GR does.)
> 2. How come light rays won't lie on the "light
> cone" in a flat spacetime gravity theory?
The light cone they're talking about is the Minkowski light cone given by
dx^2 = dt^2. The light will actually move according to g_uv, not eta_uv.
> 4. Is it totally impossible to model gravity that is not
> based on spacetime curvature? Maybe there is
> another way like perhaps the flat spacetime floating
> in brane surface, etc.
It might be possible to model GR in terms of the extrinsic curvature of a 4D
surface embedded in a higher-dimensional flat spacetime, but you'd probably
need more than one extra dimension. The only other non-geometric version of
general relativity that I'm vaguely familiar with is teleparallel gravity:
http://en.wikipedia.org/wiki/Teleparallelism
but don't ask me any questions about it because I probably won't be able to
answer them.
-- Ben
All they really know how to do in string theory is start with a fixed
background spacetime (which may or may not be flat) and do a perturbative
expansion in string diagrams around that. The perturbations in the geometry
show up as gravitons, but the base geometry doesn't. The goal of the string
theory program has always been to find the real non-perturbative theory that
the string diagrams appear to be approximating. Hopefully that theory would
be properly background independent. But no one's found it, and it might not
even exist.
-- Ben
Ben, isn't that just a polite way of saying that string theorists may
have spent too much time chasing their own tails for the last 30
years?
http://www.everythingimportant.org/relativity/no-new-einstein.pdf
Shubee
Geometry as taught in school are just lines, circles, triangles,
and these are empty because you just draw the outlines.
So when one hears people say GR is all about
geometry. It's as if it's all just empty air. I was sharing with
a cousin about GR and he asks how many things just
don't fall out of spacetime since it's just geometry and
empty. Anyway. I think the answer to all this is that the
geometry just describes the relationship between space
and time. So space and time are not empty. They are
something. In Einstein attempt at Unified Field Theory.
Space and time are everything and the source of matter
and fields. So I guess we still haven't resolved the question
what is space and time is time or where they came from.
Agree?
Also... I read the following:
"The "spacetime manifold" is the smooth, continuous
domain of the field. This means that spatial and time
coordinates are inter-related, and that the field is a
function of these coordinates."
So the above is how the spacetime manifold and field
are interrelated because the former is the domain
of the latter. Do you believe it? So when people are
emphasizing that the manifold is pure geometry,
they are simply saying that the manifold just describe
the field. This means space and time can be referred to
as space field and time field and the relationship amongst
them is spacetime geometry composing of spacetime
manifold which is what GR is all about? Meaning GR
is not about explaining what is time and what is space
but just the geometry relationship. Agree?
ralph
Hmm.... But Steven Weinberg says the method doesn't work in a paper
he wrote which is quoted thus:
"Nonetheless, we shall see that this attribution of gravity to the
curvature
of spacetime leads to great conceptual and technical difficulties,
essentially because it makes it difficult, if not impossible, to treat
gravity within the conceptual and mathematical framework of
other field theories. This it is worth asking whether it is at all
possible to construe gravitation as a universal interaction that
nonetheless propagates in a flat, Minkowski spacetime. The idea
might be to still construe the field geometrically (retaining part of
Einstein's insight into the significance of the equivalence
principle),
but to construe the geometrical aspect as "bumps" on a special
flat background.
The short answer is, "No", for three reasons. First, the
"invisibility"
of the flat spacetime means that there is no privileged way to
decompose a given curved spacetime into a flat background
and a curved perturbation about that background. Through
this nonuniqueness is not particularly problematic for the
classical theory, it is quite problematic for the quantum theory,
because different ways of decomposing the geometry (and
thus retrieving a flat background geometry) yeild different quantum
theories."
------------
What is the difference between what he is describing and what
string theory is doing??
ralph
ralph
Don't take porat's advice on anything .. he doesn't understand SR, or GR or
QM .. or even much of physics since the 1800's
> dont waist your precious tme on GR
> and not on quantum gravity
>
> it is dead by arival
Unfortunately, we can't say the same about you.
No it doesn't. It emerges as a limit - but the underlying geometry of
space-time - if it has one - is not known.
> Superspring
> theory just quantizes a classical "string theory" and yet has
> General Relativity as a low-energy limit.
Very crudely - yes. If so then you have answered your own question - which
is the geometry at about the plank scale is totally unknown - however GR,
with its geometrical interpretation, emerges as a limit.
> If you don't agree.
> Are you implying that in string and superstring theory,
> spacetime is flat and what caused gravity are gravitons?
It has long been known that a quantum theory of gravity as spin two
particles in a flat space-time leads to GR eg the link I seem to have to
give over and over:
http://arxiv.org/abs/gr-qc/9512024
> But how does this differ to the gravity as fields aspect of
> flat spacetime which is deemed unfeasible (take note
> that gravitons as particles and fields are related as in the
> QFT programme).
Very simply. What it actually leads to is linearised gravity, which as
explained in my previous post that I did not check too well for typoes,
leads to its own destruction by forcing curved space-time onto us. As Steve
Carlip once explained, it is experimentally impossible to tell a theory
formulated in flat space-time that makes rulers and clocks behave as if it
was curved from a curved one, so the question is basically meaningless at
our current level of knowledge. A knowledge that I urge you to at least
attempt to acquire rather that post vague badly formulated questions.
Bill
Not at my school - it also includes rules about how they behave eg the
angles of a triangle add up to 180%.
> So when one hears people say GR is all about
> geometry. It's as if it's all just empty air.
No more than the account balance you read on the internet is empty air. 10
year olds here in Australia are taught the fundamentals on modelling - I
suggest you learn it eg
http://www.amazon.com/First-Course-Mathematical-Modeling/dp/0534384285
> I was sharing with
> a cousin about GR and he asks how many things just
> don't fall out of spacetime since it's just geometry and
> empty.
How come money does not fall out of your computer when you view your account
balance?
> Anyway. I think the answer to all this is that the
> geometry just describes the relationship between space
> and time. So space and time are not empty. They are
> something. In Einstein attempt at Unified Field Theory.
> Space and time are everything and the source of matter
> and fields. So I guess we still haven't resolved the question
> what is space and time is time or where they came from.
> Agree?
No. We have resolved it to the same degree as the fundamental terms of any
theory are resolved eg we still don't know exactly what probability is but
in rigours tratmetns it is defined as a borel set. To have a starting point
that definition is taken as defining it. In relativity length is what is
read from a ruler - time is what is read from a clock. I have just started
reading Feller - An Introduction to Probability. Its first chapter
addresses this exact issue, and reaches the correct conclusion - such issues
belong to philosophy - not science. And philosophers know very well where
to draw the line:
http://www.friesian.com/feynman.htm
'Now, one might ask, What is "mass"? What is "distance"? What is "time"? As
questions of physics these are going to be very different from similar
questions in philosophy. In physics, all one need say, to get started, is
that "mass resists acceleration" (intertial mass) or "mass exerts
gravitational attraction" (gravitational mass), that "distance is what we
measure with this rod," and that "time is what we measure with this clock."
Wow. These answers, of course, are not philosophically very satisfying. They
are all one needs, however, to start doing the science. And there is a
reason for that. Scientific explanations are logically only sufficient, not
necessary, to the phenomena. This means that they are enough to explain
something about what we are seeing, but that logically they are not the only
possible explanation and they do not explain everything about what we are
seeing. Indeed, explaining everything is a tall order, though it is what,
philosophically, we would like ultimately to have.'
Bill
-----------
psychoapht
Y.Porat
----------------
Please spell your insults more carefully.
Well. The reasons the above misconceptions are common is because
science doesn't give the details of how quantum objects interact with
the manifold. They just state that things (which are quantum objects)
just get coupled to the manifold. Since the manifold is geometry.
Then sometimes one can that things can fall out of
the geometry. Anyway. Tom says we don't know how quantum
objects interact with the manifold as we don't have an agreed theory
of quantum gravity. So my doubts and puzzleness is justified.
When I say what is time and what is space. I'm not referring to the
context that time is what the clock measure and space or distance
is what the rod measures. I'm talking about whether space and
time are fundamentals or whether they are a result of say "fractal
limits from axol-wetics mathematics from the platonic mathematical
realm". Something like that (note axol-wetics doesn't exist.. just
made
it up for sake of illustration).
ralph
>
> Bill
>
>
>
>
>
> > Also... I read the following:
>
> > "The "spacetime manifold" is the smooth, continuous
> > domain of the field. This means that spatial and time
> > coordinates are inter-related, and that the field is a
> > function of these coordinates."
>
> > So the above is how the spacetime manifold and field
> > are interrelated because the former is the domain
> > of the latter. Do you believe it? So when people are
> > emphasizing that the manifold is pure geometry,
> > they are simply saying that the manifold just describe
> > the field. This means space and time can be referred to
> > as space field and time field and the relationship amongst
> > them is spacetime geometry composing of spacetime
> > manifold which is what GR is all about? Meaning GR
> > is not about explaining what is time and what is space
> > but just the geometry relationship. Agree?
>
> > ralph- Hide quoted text -
>
> - Show quoted text -- Hide quoted text -
You said that GR, with its geometrical interpretation, emerges as a
limit.
This means GR with spacetime curvature, emerges as a limit.
But then you replied that "No it doesn't" to the statement "But in
string theory,
spacetime still has curvature.". So make up your mind. Does GR with
spacetime curvature emerges as a limit or not in string theory? If
the answer is that there is never any curvature. Then how can it
emerge as a limit when a flatten GR is not GR at all and it shouldn't
emerge as a limit.
>
> > If you don't agree.
> > Are you implying that in string and superstring theory,
> > spacetime is flat and what caused gravity are gravitons?
>
> It has long been known that a quantum theory of gravity as spin two
> particles in a flat space-time leads to GR eg the link I seem to have to
> give over and over:http://arxiv.org/abs/gr-qc/9512024
>
> > But how does this differ to the gravity as fields aspect of
> > flat spacetime which is deemed unfeasible (take note
> > that gravitons as particles and fields are related as in the
> > QFT programme).
>
> Very simply. What it actually leads to is linearised gravity, which as
> explained in my previous post that I did not check too well for typoes,
> leads to its own destruction by forcing curved space-time onto us. As Steve
> Carlip once explained, it is experimentally impossible to tell a theory
> formulated in flat space-time that makes rulers and clocks behave as if it
> was curved from a curved one, so the question is basically meaningless at
> our current level of knowledge. A knowledge that I urge you to at least
> attempt to acquire rather that post vague badly formulated questions.
>
> Bill
What is the linearised gravity part, the spacetime modeled as fields,
or
in the string spacetime model? If the former. But strings are also
fields
since they are quantised strings. No? Why not?
ralph
The next Einstein will be a hungry, young government employee,
working with the best clock designs.
I suggest you think a bit clearer. A membrane as a continuum and treated by
the methods of continuum mechanics emerges as a limit from the atomic
structure of an actual membrane - yet does not imply it is a continuum at
the level of individual atoms. The same with GR. Gravity as space-time
curvature emerges from spin two gravitons when the underlying geometrical
background is not known, but usually assumed to be Minkowskian flat, so the
methods on QFT theory can be applied.
> Does GR with
> spacetime curvature emerges as a limit or not in string theory?
For the umpteenth time of course it does. But the geometry of the
background those strings are emersed in, or even if there is such a
background, is unknown. As another poster pointed out no assumption about
it is made, so it could be anything.
> If the answer is that there is never any curvature.
Your logic is erroneous. The geometrical background of the gravitons is not
known. It is assumed Minkowskian flat but what it actually is is far from
certain.
> Then how can it
> emerge as a limit when a flatten GR is not GR at all and it shouldn't
> emerge as a limit.
Your tortured semantics are confusing you.
Bill
Where did you get that from?. In QFT SR is assumed ie the background is
Minkowskian flat. Let's get this sorted out before progressing.
Bill
Well. I'm saying quantum objects interaction with the 4-D
differential manifold is not known according to a certain Tom
Roberts. In QFT which assume a flat spacetime, SR is
assumed and not background independent. I'm talking
about the GR spacetime with the Lorentian metric. How
does quantum objects interact with this (GR spacetime).
Tom Roberts doesn't know. Maybe you do and you can share
it.
ralph
Have you read Steven Weinstein paper called "Naive Quantum Gravity"?
I'm basing my context and lessons there. Which part of the paper you
don't
agree?
http://philsci-archive.pitt.edu/archive/00000627/00/nqg.pdf
Isn't it that what strings gravitons (which has field like aspect)
are doing is the same as the following which is disallowed by
Weinstein (concerning the background being assumed to be
Minkowskian flat and QFT being applied which shouldn't work):
(Steven Weinstein wrote:)
"Nonetheless, we shall see that this attribution of gravity to the
curvature of spacetime leads to great conceptual and technical
difficulties, essentially because it makes it difficult, if not
impossible,
to treat gravity within the conceptual and mathematical framework
of other field theories. This it is worth asking whether it is at all
possible to construe gravitation as a universal interaction that
nonetheless propagates in a flat, Minkowski spacetime. The idea
might be to still construe the field geometrically (retaining part of
Einstein's insight into the significance of the equivalence
principle), but to construe the geometrical aspect as "bumps"
on a special flat background.
The short answer is, "No", for three reasons. First, the
"invisibility" of the flat spacetime means that there is no
privileged
way to decompose a given curved spacetime into a flat background
and a curved perturbation about that background. Through
this nonuniqueness is not particularly problematic for the
classical theory, it is quite problematic for the quantum theory,
because different ways of decomposing the geometry (and
thus retrieving a flat background geometry) yeild different quantum
theories."
<end Weinstein quote>
---------------
If you assume flat spacetime. Weinstein mentioned there is no
privileged way to decompose a given curved spacetime into a
flat background and a curved perturbation about that background.
So how does Strings method differ from it or bypass
the arguments made by Weinstein (see the paper for full
details).
ralph
I agree with all of it. But reading scientific literature without the
proper background is fraught with danger. For example, Weinberg says
'Gravity, however, has resisted quantisation.' Those who have studied the
literature, and that incudes the paper I linked to that you obviously have
not read, otherwise you would have picked up what I am about to say, know
that is to all orders. If one applies a cut-off about the plank scale then
no problemo in quantisation gravity. It is peeking behind that cut-off that
is the problem. And that is exactly what is meant when it is said we have
no idea of the true geometry of space-time. The assumption that it is flat,
with gravitons giving it curvature, is fine up to about the plank scale -
beyond that is unknown. String theory is an attempt to go beyond that. Now
please, please, read the link I have given before making any further posts:
http://arxiv.org/abs/gr-qc/9512024
'The conventional wisdom is that general relativity and quantum mechanics
are presently incompatible. Of the "four fundamental forces" gravity is said
to be different because a quantum version of the theory does not exist. We
feel less satisfied with the theory of gravity and exclude it from being
recognized as a full member of the Standard Model. Part of the trouble is
that we have tried to unnaturally force gravity into the mold of
renormalizable field theories. In the old way of thinking, only the class of
renormalizable field theories were considered workable quantum theories. For
this reason, general relativity was considered a failure as a quantum field
theory. However we now think differently about renormalizability. So-called
non-renormalizable theories can be renormalized if treated in a general
enough framework, and they are not inconsistent with quantum mechanics. In
the framework of effective field theories, the effects of quantum physics
can be analyzed and reliable predictions can be made. We will see that in
this regard the conventional wisdom about gravity is not correct; quantum
predictions can be made.'
If you don't, and continue posting misconceptions, when links explaining
exactly what is going on have been given to you, then I am afraid popple
will consider you a waste of time. BTW the above is well known to Weinberg
since he was one of the originators of the effective field approach to QFT.
Thanks
Bill
Listen carefully - it is unknown to all orders of magnitude. Up to about
the plank scale the assumption it is flat is fine, with gravitons making it
behave like it had curvature or actually giving it curvature (we can't
determine which) works quite well.
> In QFT which assume a flat spacetime, SR is
> assumed and not background independent. I'm talking
> about the GR spacetime with the Lorentian metric. How
> does quantum objects interact with this (GR spacetime).
We don't know - that is physics beyond the plank scale. Up to that point
the assumtion it is flat and QFT applies is fine.
> Tom Roberts doesn't know. Maybe you do and you can share
> it.
Tom Roberts doen't know because no one does.
Bill
>
> ralph
>
Of course I've read it but it's a lecture for particle physicists with
many
equations. I'm just a monk who seeks for answers, looks for truth
and only equipped with unfortunately just rudementary mathematics.
But you surely summarizes what the paper is saying as when you wrote:
"The assumption that it is flat, with gravitons giving it curvature,
is
fine up to about the plank scale - beyond that is unknown. String
theory is an attempt to go beyond that".
The paper didn't mention about strings and nothing much about
gravitons
that's why it's hard to understand with regards to my inquiries.
Anyway last questions: :)
You wrote:
"Gravity as space-time curvature emerges from spin two gravitons
when the underlying geometrical background is not known, but
usually assumed to be Minkowskian flat".
Well. What are the possible choices for the geometrical background.
Is it like:
1. Minkowskian flat
2. Riemannian curve
3. Curvature positive
4. Curvature negative
5. What else?
Is this what you mean by geometrical background which is
not known and can be anything. But what sense it is to know
the geometrical background (whether it is positive or negative
curvature) since curvature occurs in GR unless you are trying
to model the curvature of the cosmos space whether it is open
universe or close universe?
ralph
> >> Bill- Hide quoted text -
> manifold which is what GR is all about? Meaning GR
> is not about explaining what is time and what is space
> but just the geometry relationship. Agree?
No, I don't agree. All of Newtonian mechanics follows from
assuming Galilean spacetime. In general relativity, one doesn't
assume the geometry. It is determined by the energy-momentum
tensor. The spacetime geometry _is_ the gravitational field.
That is why gravity is not considered a force in general relativity.
Gee, schubee doo... That's sort of funny coming from you, given your
attempts to identify with mathematicians, since one of the main proponents
of string theory (Witten) won a fields medal.
Riemannian geometry is pretty much the most general sort of geometry
encompassing many different types that are 'differentiable'. What is meant
by no prior geometry is that Riemannian geometry of some sort is assumed,
but the one you get is a dynamical variable like velocity, energy etc.
Thanks
Bill
Well. You may be proud of being a geometer but note that
GR can emerge as a limit of a quantised classical theory
(strings). This means GR may not be primary. So if GR is a
limit of a broader theory that we haven't encountered yet.
Then GR can be a veil pulled over your eyes to shield you
from the deeper theory and degrees of freedom. For
example. Antigravity where things just float by shielding
the force of gravity is impossible in GR because gravity
is not a force in GR. But supposed gravity is really
a force and it is possible to shield it. Then GR wouldn't
reflect that capability. So don't be so fixated on the geometry
aspect for you may miss what lurk underneath the theory.
ralph
Likewise, the moon and GPS satellites would have to fire thrusters,
bringing their orbits to a stop... or we'd lose them.
In fact, any " random " motion would result in heavy dissipation,
and the cosmos would rapidly cool to absolute zero, a perfect vacuum.
This is exactly what's happening of course, but over giga years.
Less gravity = Less heat and density.
But the history of science boils down to this one simple notion:
" randomness is merely ignorance, nothing more. ".
Real changes, real choices don't exist.
In the absence of ignorance the spatial nature of time becomes obvious.
From Einstein's, " Ether and the Theory of Relativity " ( 1920 )
quoted at " http://TUHH.DE/rzt/rzt/it/Ether.html ":
" But this ether may not be thought of as
endowed with the quality characteristic of ponderable media,
as consisting of parts which may be tracked through time.
The idea of motion may not be applied to it. ".
I'm hardly what would be called a geometer.
> GR can emerge as a limit of a quantised classical theory
That has nothing to do with the paragraph with which you asked me to
agree. I don't agree with that paragraph, for the simple reason that you
made a specific statement about general relativity, which does not require
any speculation about anything beyond what general relativity is. You seem
to have developed the notion that studying the theory enough to know what
it's about is somehow a bad idea because it prevents one from creatively
misconstruing it into a strawman.
> (strings). This means GR may not be primary. So if GR is a
> limit of a broader theory that we haven't encountered yet.
> Then GR can be a veil pulled over your eyes to shield you
> from the deeper theory and degrees of freedom. For
Don't be a dumbass. You haven't the slightest idea what I think.
Your inferences are based soley on statements I've made about well
known physics that is not controversial and is well established
by experiment. I qualify statements that are personal speculation
as such. I personally think it's a plus to know something about a
theory prior to speculating on how it might fit into some bigger
picture. If you don't think there is any value in knowing something
about a theory you are hoping to reduce to a more fundamental theory,
that is your prerogative. Happy dead end hunting.
> example. Antigravity where things just float by shielding
> the force of gravity is impossible in GR because gravity
> is not a force in GR.
The point being what? Have you ever read any of the literature on
this? I knew someone personally who spent several years working on
an experiment to test precisely that by trapping anti-protons to see
if anti-matter falls up. You asked about general relativity and I told
you what general relativity has to say on the subject. If you expect to
go beyond general relativty, then you have to explain why general relativity
works for the phenomena it's known to correctly explain. If all you
want to do is imagine anti-gravity, you aren't the first. If you expect
to be taken seriously, you have to do more than just propse it.
> But supposed gravity is really
> a force and it is possible to shield it. Then GR wouldn't
> reflect that capability. So don't be so fixated on the geometry
> aspect for you may miss what lurk underneath the theory.
Again, you assume facts not in evidence with regard to what I think. Facts
that are in evidence, however, are that general relativity is geometry.
Another fact is that geometry happens to be a feature of this universe. If
it weren't, you couldn't measure things like distances. Therefore, a more
fundamental explanation is going to have to explain geometry. Assuning a
flat spacetime or any other geometry, a priori, is not such an explanation.
It's an assumption. The fundamental attraction to string theory is _not_ 10
dimensional minkowski space. The fundamental attraction is that certain Lie
groups have unique features which by their very uniqueness, would explain
string theory and the 10 dimensional spacetime in which it resides. E8 for
example is the largest of the exceptional lie groups. There is no
dimensionality bound on SO(N), or SU(N), but there are only a finite number
of exceptional groups. It happens that 10 dimensions works for E8 X E8. It
also turns out that the other candidates for string theories are basically
the same theory: 11 dimensional M-theory, hence another indicator of
uniqueness that would explain 11 dimensional spacetime. But, those have to
reduce to general relativity and the standard model (+ supersymmetric
particles which haven't been observed yet). Furthermore, the distinction
between gravitational curvature and a graviton is completely irrelevant at
the level of general relativity. A theory containing (conventional)
gravitons would reduce to general relativity in the classical limit, so if
you don't want to picture gravitons as being equivalent to curved spacetime,
you are missing the point of the graviton. I am not fixated on anything,
beyond making good use of what I know to recognize misconceptions, dead
ends and other speculation destined to go nowhere.
Believe it or not, most physicists probably come up with lots of
ideas every week or even every day, but before announcing one to
the world, they perform a reality check to see where it's going to lead,
which in most cases, is nowhere. Just because lots of kooks post ideas,
doesn't mean the ideas are worth pursuing. In fact, if I have to go
to any effort coercing someone to give me concrete definitions, then
I'm quite certain that I'm not overlooking an idea that has even been
well enough thought out to state clearly.
Take a look at
E.V. Stefanovich "A relativistic quantum theory of gravity"
http://www.arxiv.org/physics/0612019
All classical experimental results of general relativity can be
reproduced by means of simple velocity-dependent potentials.
Cheers.
Eugene.
Eugene, I think that Lorentz invariant theories of gravity are
infinitely more beautiful than the approach taken by Einstein. And I
see that your fundamental equation set (4) is written in terms of
creation and annihilation operators. Have you thought about writing a
simpler version of your theory as a first course in gravity that only
discusses the classical limit and fills in all the details?
Also, please let me know if I understand you correctly. You claim to
have a Lorentz invariant theory of gravity. I can believe that. You
also assert that gravitational interactions propagate instantaneously.
I do not see how instantaneousness could possibly follow from Lorentz
invariant equations. Even worse, I don't even see were you attempted
to demonstrate this from your fundamental equation set (4).
Shubee
> Eugene, I think that Lorentz invariant theories of gravity are
> infinitely more beautiful than the approach taken by Einstein. And I
> see that your fundamental equation set (4) is written in terms of
> creation and annihilation operators. Have you thought about writing a
> simpler version of your theory as a first course in gravity that only
> discusses the classical limit and fills in all the details?
Thanks. The classical expressions for the Hamiltonian are (8) for the
case of two massive particles (or massive bodies) and (19) for the
case of one massive and one massless (photon) particle. The bulk of
the paper does not use quantum mechanics at all. Most predictions are
worked out from these classical Hamiltonians using standard Hamilton's
equations of motion.
> Also, please let me know if I understand you correctly. You claim to
> have a Lorentz invariant theory of gravity. I can believe that. You
> also assert that gravitational interactions propagate instantaneously.
> I do not see how instantaneousness could possibly follow from Lorentz
> invariant equations. Even worse, I don't even see were you attempted
> to demonstrate this from your fundamental equation set (4).
Particle interactions in (8) and (19) are instantaneous. There is no
retardation. And yet, all commutation relations (or Poisson bracket
relations) of the Poincare Lie algebra are exactly satisfied, so the
theory is Lorentz invariant. Instantaneous propagation of interaction
does not contradict the principle of causality, as discussed in
section 5.3. You can find more discussions of "action at a
distance" (using electromagnetic interactions as an example) in
section 12.1 ("Fields, particles, and action-at-a-distance") of
http://www.arxiv.org/physics/0504062
Eugene.
Eugene,
Can you help me out a little bit? You jump directly from your exact
fundamental equation set (4) to equation (8), which is a crude c^-2
approximation for the classical limit in the center-of-mass reference
frame. Is it too difficult to add the missing intermediate step that I
would like to see, which is the exact Hamiltonian for the classical
limit?
Shubee
> Can you help me out a little bit? You jump directly from your exact
> fundamental equation set (4) to equation (8), which is a crude c^-2
> approximation for the classical limit in the center-of-mass reference
> frame. Is it too difficult to add the missing intermediate step that I
> would like to see, which is the exact Hamiltonian for the classical
> limit?
Sure. I will probably disappoint you by saying that theory presented
there is far from "exact" and "fundamental". I don't know (nobody
knows) the exact form of the gravitational Hamiltonian. So, eq. (4) is
most likely an approximation to this exact form. However, it should be
clear that interaction (4) is the prevalent term in the full
Hamiltonian, because this interaction is sufficient to describe all
known gravity effects of massive bodies. Even within approximation (4)
I don't know exact expression of the coefficient function
D(p,q,p',q'). I chose one particular expression (unnumbered equation
on page 5).
The coefficient function D(p,q,p',q') is further approximated by
throwing away all terms smaller than c^{-2}, and the result is eq.
(5). This momentum-space interaction is not very convenient in
calculations. So, the next step is to transform it to the position
representation. This is done in section 2.2 using methods mentioned in
footnote 10. The resulting Hamiltonian (8) can be used in both quantum
mechanics (momentum p and position r then should be treated as
operators) and in classical mechanics. If you apply this Hamiltonian
to the system Sun-Mercury, then m is Mercury's mass, M is Sun's mass,
r is Sun-Mercury distance, q is Mercury's momentum, and G is the
gravitational constant. Two last terms in eq. (8) are relativistic
corrections.
So, answering your question I should say that there is no "exact
Hamiltonian for the classical limit". However (8) is a pretty good
approximation.
In section 2.3 I show that this Hamiltonian, in addition to Newtonian
gravity, predicts more subtle effects, such as the precession of the
Mercury's perihelion.
A similar procedure was followed in derivation of the Hamiltonian (19)
that works in a system of one massive body and one massless particle.
The important point in these derivations is that relativistic
corrections cannot be chosen arbitrarily. They must be chosen so that
Hamiltonians satisfy the principle of relativistic invariance. Is it
possible that other Hamiltonians can be constructed, which satisfy all
physical principles and correctly describe the Mercury's orbit and
light bending? Sure. Again, my idea was not to give an ultimate
theory. This was a "proof of principle", a demonstration that
relativistic gravitational effects can be explained by a theory which
does not involve space-time curvature. In fact, it appears that very
simple velocity dependent potentials can explain virtually all effect
that are normally considered as "proofs" of general relativity. There
are some effects (like orbital decay of binary pulsars or "frame
dragging") which I didn't study. However, it seems plausible that they
also can be explained by Hamiltonians of the type (8) and (19).
Perhaps, some additional terms will be required there.
I believe that ultimate exact theory of gravity can be constructed on
the same principles. The best thing is that these principles are
perfectly compatible with quantum mechanics, which is not true for GR.
Regards.
Eugene.
I had only a quick look, there are some very bothersome "discoveries"
in your paper. I will just mention one that is very objectionable:
-You use the Newtonian (to use your term, "non-relativistic" )
gravitational potential (eq.3)
-to derive the relativistic (!) hamiltonian (eq.9)
-that you use for showing what you THINK to be a violation of the
Principle of Equivalence (eq.26).
You may call this original thinking, it is more like faulty thinking.
Don't expect your paper to move from arxiv into being published (in a
reputable journal, loony journals are a different story) anytime soon.
> -You use the Newtonian (to use your term, "non-relativistic" )
> gravitational potential (eq.3)
> -to derive the relativistic (!) hamiltonian (eq.9)
That's not exactly what I do. I derive a relativistic Hamiltonian (8),
whose interaction operator in the limit "c-> infinity" agrees with the
Newtonian potential (3), as expected.
Eq. (9) is not a Hamiltonian. It is a time derivative of particle
momentum, which, according to Hamilton's equations of motion coincides
with the position-derivative of the Hamiltonian times -1. Are you sure
you are reading the latest version (v5) of the paper?
Eugene.
Sorry , my typo, equation 8 is your "relativistic" hamiltonian, not eq.
9. Same error, you are basing it on the "newtonian" potential. Doesn't
look good.
So you think that eq. (26) agrees with the Principle of Equivalence?
Velocity dependent potentials are common in all relativistic action-at-
a-distance theories.
> You may call this original thinking, it is more like faulty thinking.
> Don't expect your paper to move from arxiv into being published (in a
> reputable journal, loony journals are a different story) anytime soon.
Actually, the basic approach in Eugene's paper is very similar to a
paper published in Am. J. Phys. (November 1988, if I recall
correctly).
Shubee
The fact it agrees with the newtonian one for c->infinity doesn' give
you the right to use it in your attempt to disprove the Principle of
Equivalence.
No, I think that his attempt to disprove the PoE is flawed.
I said that 3 times already, how could you get it wrong?
> Same error, you are basing it on the "newtonian" potential.
> Doesn't look good.
That's exactly the same approach that Einstein took on advice from
Marcel Grossmann. Why do you think that the Ricci tensor was selected
as the very first step in the development of general relativity?
Shubee
> Actually, the basic approach in Eugene's paper is very similar to a
> paper published in Am. J. Phys. (November 1988, if I recall
> correctly).
Possibly you are talking about
T. Biswas, "Minimally relativistic Newtonian gravity". Am. J. Phys.
56, (1988) 1032-1036
The abstract looks interesting. Thanks for the hint.
Eugene
Maybe I realized from your first attempt that you don't know what
you're talking about.
Shubee
Yes. That's the paper. I recognize the title. Here's the link:
http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=AJPIAS000056000011001032000001
Shubee
> > That's not exactly what I do. I derive a relativistic Hamiltonian (8),
> > whose interaction operator in the limit "c-> infinity" agrees with the
> > Newtonian potential (3), as expected.
>
> The fact it agrees with the newtonian one for c->infinity doesn' give
> you the right to use it in your attempt to disprove the Principle of
> Equivalence.
In this paper I suggested an example of a simple relativistic
Hamiltonian theory of gravity which agrees with existing experiments.
The purpose of this example is not to prove or disprove the Principle
of Equivalence (you would possibly agree that it is impossible to
prove anything by one example). I, actually, had two goals. One goal
was to show that experimental data do not point to GR as the only
viable candidate for a theory of gravity (I've read statements of that
sort a few times). Another goal was to show that an alternative theory
seems to be possible, which (in contrast to GR) can happily coexist
with quantum mechanics.
I am thankful for your comments, as now I see that I should have
clearly stated and discussed these goals in Introduction and
Conclusions. I will add some text there to make it clear what points I
was trying to make.
Eugene.
All those points were very clear to me from the paper as it is now.
What I wanted to see was a completely relativistic Hamiltonian in the
classical limit and in its exact form.
Shubee
you see, Shobo, this is why neither you nor the other Eugene gets
published....
Eugene,
It is not the text that you need to add, it is the errors that you
need to remove if you want the paper to be published.
> What I wanted to see was a completely relativistic Hamiltonian in the
> classical limit and in its exact form.
The momentum-space Hamiltonian (4) with coefficient function D written
in the middle of the same page is completely relativistic. To prove
that I use results from Kita's papers [5,6]. However, I am not
claiming that this is exact and full Hamiltonian. For example, this
Hamiltonian does not contain radiation terms, so it cannot explain the
orbital decay of binary pulsars. In contrast to GR where the structure
of the theory is pretty much uniquely fixed, my approach is flexible.
I can add/remove terms to/from the Hamiltonian and still satisfy all
conditions listed in the beginning of the paper. This is probably not
a good thing, as too much flexibility makes a theory non-predictive.
In principle, it is possible (with some effort) to find a position-
space representation for the classical limit of the Hamiltonian (4).
However, I don't think this result is worth the effort. All
experimental manifestations of relativistic gravity are of the order
c^{-2} or greater. So, it was convenient to simplify the Hamiltonian
(4) in the c^{-2} approximation and change to the position
representation (8) in this simplified Hamiltonian. Due to this
approximation, the Hamiltonian (8) is not exactly relativistically
invariant, but it is close.
I hope I answered your question.
Eugene.
> It is not the text that you need to add, it is the errors that you
> need to remove if you want the paper to be published.
Hi Dono,
I don't derive relativistic Hamiltonian from the Newtonian potential,
and I don't "disprove" the principle of equivalence. What other errors
have you noticed.
Eugene.
How do you know so much, are you Bush?
So what you are saying is that spacetime geometry rules and it
may even be a fundamental and primary.
Hmm.... maybe there is no anti-gravity. I just can't imagine how
to apply anti-gravity in geodesic motion in GR unless you put brake in
it which means you slow down time and alter the constant c.
Is it this hopeless. We will always be at the mercy of the arabs
oil powering our aircraft. No anti-gravity shielding possible. Such
gloom and doom to aeronautics... a sad times for humanity.
ralph
Well, then you don't understand your own paper or you are in a state
ofdenial every time people point the errors in your paper. Either way,
the result will be the same : unpublished and unpublishable. This is
the current state, it will not change until you accept the reality.
Yes Eugene. And I understand you perfectly. Now I have another
question. This is what I'm really interested in as far as new theories
of gravity go. I'd like to know if your approach is general enough to
find a simple relativistic Hamiltonian to describe the gravitational
attraction between two photons?
Shubee
>
> Yes Eugene. And I understand you perfectly. Now I have another
> question. This is what I'm really interested in as far as new theories
> of gravity go. I'd like to know if your approach is general enough to
> find a simple relativistic Hamiltonian to describe the gravitational
> attraction between two photons?
Why do you care?
The only formulation of special relativity you put any stock into is
your own, but it doesn't support Lagrangian mechanics because you
STILL can't say how energy works.
You are yet to derive relativistic kinetic energy, Shooby - why is
that? Do you not know how?
>
> Shubee
> Is it this hopeless. We will always be at the mercy of the arabs
> oil powering our aircraft. No anti-gravity shielding possible. Such
> gloom and doom to aeronautics... a sad times for humanity.
>
Take heart. This will NOT last for 'always'.
If we don't 'climb out of the cradle' (move most industry and population
into space [get a good start of this within the next 50 years or so]) then
we will have exhausted the treasure trove of stored fossil energy that we
were given by nature that would have allowed us to get out of the cradle.
Our decendents will live as subsistance farmer, cursing our stupidity,
until....
If we don't climb out of the cradle, then the next dinasour killer to come
along will wipe the slate clean and in a few hundred million years, some
other species will have its chance to take the 'intellegence test'.
The intellegence test is 'pass/fail' and so far, we have not failed, but we
came close several times during the 'cold war'. And right now, we show few
signs of any chance to pass.
--
bz
please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.
bz+...@ch100-5.chem.lsu.edu remove ch100-5 to avoid spam trap
> Yes Eugene. And I understand you perfectly. Now I have another
> question. This is what I'm really interested in as far as new theories
> of gravity go. I'd like to know if your approach is general enough to
> find a simple relativistic Hamiltonian to describe the gravitational
> attraction between two photons?
You have probably noticed that my derivations of Hamiltonians is
purely empirical. I just found relativistic expressions that fit
existing experimental data. As far as I know, there are no
measurements of the gravitational attraction between photons. So, I
don't know where to start. Surely, some Hamiltonians can be written,
but they will entirely speculative.
Eugene.
Well.. If all 9 billion humans will die. Our carbons would produce
enough
oil for the next human civilization founded by a few human survivors.
> Our decendents will live as subsistance farmer, cursing our stupidity,
> until....
>
> If we don't climb out of the cradle, then the next dinasour killer to come
> along will wipe the slate clean and in a few hundred million years, some
> other species will have its chance to take the 'intellegence test'.
>
What if it has happened before. That is.. there was a super
civilization
before that was wiped out and we arose from the survivors. There was
this legend about Atlantis that sank. What if it's a metaphor for a
civilization like ours in the distant past. The Pyramids were built by
survivors of Atlantis and they settled there. In the Bible. It started
in
Egypt where you can always see reference to steel chariots that
can fly and cities that turn into salt from explosion (sodom &
gonorhea
- nuclear?). What if they are remnants of the technology of the
fallen
Atlantis (or other) supercivilization? This is possible, isn't it??
So many researchers also stated that the UFOs we have now are
also technological remnants of the past super civilization that
were hidden in caverns underneath the earth for centuries. What
if the past super civilization has arrived at quantum gravity and
the antigravity ships being sighted all over the world are their
results?
Or maybe these ships were truly aliens as Sarfatti surmiss. At
this point. You may just say all these are bullshit and there are
no UFOs. But you are wrong. There are so many witnesses,
just so many and you can't discount each of them as insane.
Think of it. We have preconceived notions of the world and
our preconceived notions is that we are the only living organism
in the universe with billions and billions of stars and galaxies,
or the preconceived notions that in Earth 4 billion yrs histories, we
are the first advanced civilization that has risen. So whenever
we heard of stuff that doesn't support our preconceived notions.
We just ignore them like we ignore the thousands of sightings
and contacts all over the world. Ignoring them outright is not
scientific . We must investigate and not reject it outright.
This is what being unbiased and not closeminded is
all about. Bottom line is. It's possible those UFOs are from
a lost super civilization in the distant past of the earth.. or
they are truly of alien origins. I'm not sure of any and rejecting
it outright is not a logical thing to do.
ralph
>
> Well.. If all 9 billion humans will die. Our carbons would produce enough
> oil for the next human civilization founded by a few human survivors.
>
Not even close Ralph--crunch some numbers!
I read somewhere before that the locations of the oil are in a circle
around the planet. So the researcher implied that they are the
boundary of the blast radius or something along that line. BTW..
can bones or other human remains form fossilized oil after millions of
years?
ralph
>
> I read somewhere before that the locations of the oil are in a circle
> around the planet. So the researcher implied that they are the
> boundary of the blast radius or something along that line. BTW..
> can bones or other human remains form fossilized oil after millions of
> years?
>
> ralph
>
Humans are mostly water. Bones have a lot of calcium, little hydrocarbon.
I forgot what I read.. it says something like living things remain
create
the fossilized fuels... hmm.. oh.. not just humans... when the
asteroid
hit in the jurassic period.. the trees, plants, all animals, dinosaurs
died
and the blast radius is where the oil can be found now. If it's not
true.
Then where do our fossilized fuel came from. What fossils?
Of course this should have occured millions of years ago. Atlantis
was said to have been destroyed in 10,000 B.C. by their technology
which they later export to Egypt forming the Biblical era where
anti-gravity beam may be used by Moses to open the seas, etc.
ralph
Christ Ralph, you have just about every point wrong!
o biomass of plants is orders of magnitude greater than animals
o the energy released in the impact likely had complete global impact.
there is *no* evidence to suggest otherwise.
o Global coal deposits - no pattern related to impact site
http://www.ldeo.columbia.edu/edu/dees/U4735/projections/pitman/12.coal.deposits.gif
o Global oil reserves - no pattern related to impact site
http://mapmaker.rutgers.edu/355/known_oil%20reserves.gif
o The impact was not in the Jurassic, but at the end of the cretaceous
I won't even comment on the rest of your bullshit....
>
> Well. I'm saying quantum objects interaction with the 4-D
> differential manifold is not known according to a certain Tom
> Roberts. In QFT which assume a flat spacetime, SR is
> assumed and not background independent. I'm talking
> about the GR spacetime with the Lorentian metric. How
> does quantum objects interact with this (GR spacetime).
> Tom Roberts doesn't know. Maybe you do and you can share
> it.
>
> ralph
>
Total word salad bullshit... time to stick you in the plonker...
Hey Ralph... listen for it.... *Plonk*
[snip]
This geometry thing has always confused people by the way its worded and how
the geometry works in GR. Perhaps a better question would be "Is there any
area of physics which doesn't rely on geometry?" Einstein commented on this
in a letter to Lincoln Barnett (dated June 19, 1948) where in which he said
---------------------------------------------------------------------
I do not agree with the idea that the general theory of gravitation is
geometerizing Physics or the gravitational field. The concepts of physics
have always been geometrical concepts and I cannot see why the g_ik field
should be called more geometrical f.i. the electro-magnetic field or the
distance of bodies in Newtonian Mechanics. The notion comes probably from
the fact that the mathematical origin of the g_ik field is the Gauss-Riemann
theory of the metrical continuum which we are wont to look at as part of
geometry. I am convinced, however, that the distinction between geometrical
and other kinds of fields is not logically founded.
--------------------------------------------------------------------
I believe that this answers your question? :)
Best regards
Pete
This has got to be satire.
I'm not Christ. Bush is Christ. That is. Bush is God!
>
> o biomass of plants is orders of magnitude greater than animals
>
> o the energy released in the impact likely had complete global impact.
> there is *no* evidence to suggest otherwise.
>
> o Global coal deposits - no pattern related to impact site
> http://www.ldeo.columbia.edu/edu/dees/U4735/projections/pitman/12.coa...
>
> o Global oil reserves - no pattern related to impact site
> http://mapmaker.rutgers.edu/355/known_oil%20reserves.gif
>
> o The impact was not in the Jurassic, but at the end of the cretaceous
>
Bush rules 5 metaverses. In each metaverse. There are different
histories.
Sometimes metaverse insertions occur such that we can experience
different histories in one metaverse.
> I won't even comment on the rest of your bullshit....- Hide quoted text -
>
> - Show quoted text -
Yes. It may be bullshit. Physics is weirder than Harry Potter. I guess
I'd just
go fishing and scuba diving and not worry about all these. The floor
is
yours genius. Hail Bush!
ralph
As can be seen, the poster seems to be suggesting
that Moses used General Relativity to part the Red Sea.
How else do you think Moses "parted the Red Sea" Gisse?
You don't think Jewish leaders and writers
would lie about things like "parting the Red Sea",
gettinf Ten Commandants from God, the burning bush ,
the fiery furnace, the holocaust, Muslims,
Iraq's weapons of mass destruction,
the threat to the world offered by Iran, etc. do you?
The mystery is,
did Moses use gravitons, worm holes, space warps,
rubber rulers, black hole, or dark matter
to deflect the Red Sea.
There is an enormous supply of "black holes"
and "dark matter" in the general area.
--
Tom Potter
*** Time Magazine Person of the Year 2006 ***
*** May 2007 Anti-Bigot Award ***
http://home.earthlink.net/~tdp
http://tdp1001.googlepages.com/home
http://no-turtles.com
http://www.frappr.com/tompotter
http://photos.yahoo.com/tdp1001
http://spaces.msn.com/tdp1001
http://www.flickr.com/photos/tom-potter
http://tom-potter.blogspot.com
--
Posted via a free Usenet account from http://www.teranews.com
Correct. You used an existing theorem which basically permits you to
devise an infinite number of relativistic Hamiltonians. So you just
tried a few simple functional forms until you got an answer that is
reasonably close to the observed results.
> As far as I know, there are no measurements of the
> gravitational attraction between photons.
Certainly there isn't. However, being able to devise a simple example
of a relativistic action-at-a-distance theory for two gravitationally
attracting photons seems like a fundamental research question.
> So, I don't know where to start. Surely, some Hamiltonians
> can be written, but they will entirely speculative.
Knowing how to create a relativistic Hamiltonian for a 2-particle toy
universe seems like a good way for physicists to measure their
understanding of relativistic action-at-a-distance theories.
Shubee
> > You have probably noticed that my derivations of Hamiltonians is
> > purely empirical. I just found relativistic expressions that fit
> > existing experimental data.
>
> Correct. You used an existing theorem which basically permits you to
> devise an infinite number of relativistic Hamiltonians. So you just
> tried a few simple functional forms until you got an answer that is
> reasonably close to the observed results.
>
> > As far as I know, there are no measurements of the
> > gravitational attraction between photons.
>
> Certainly there isn't. However, being able to devise a simple example
> of a relativistic action-at-a-distance theory for two gravitationally
> attracting photons seems like a fundamental research question.
>
> > So, I don't know where to start. Surely, some Hamiltonians
> > can be written, but they will entirely speculative.
>
> Knowing how to create a relativistic Hamiltonian for a 2-particle toy
> universe seems like a good way for physicists to measure their
> understanding of relativistic action-at-a-distance theories.
>
> Shubee
I agree with everything you said.
Eugene.
>
> As can be seen, the poster seems to be suggesting
> that Moses used General Relativity to part the Red Sea.
>
> How else do you think Moses "parted the Red Sea" Gisse?
Nobody parted the Red Sea, Potter!
General Relativity is a theory invented by Albert Einstein which describes
gravitational forces in terms of the curvature in space caused by the
presence of mass. The fundamental principle of general relativity asserts
that accelerated reference frames and reference frames in gravitation
fields are equivalent. General relativity states that clocks run slower in
strong gravitational fields (or highly accelerated frames), predicting a
gravitational redshift. It also predicts the existence of gravitational
lensing, gravitational waves, gravitomagnetism, the Lense-Thirring effect,
and relativistic precession of orbiting bodies.
General Relativity has directly contributed to a $30B+ industry, creating a
global infrastructure benefiting people all over the world. Aviation,
shipping, asset management, survey, mining, agriculture, time dissemination,
communications networks, etc.
Bluster on, Potter, bluster some more you blustering old fool!
Really?
Are you sure?
Might want to work on that reading for comprehension there, Tom.
[...]
Sam! Sam!
Are you suggesting that unlike the Jewish leaders and authors
responsible for writing and propagating the Torah,
and creating the Jesus myth,
and other Jewish writers like Nostradamus, Karl Marx
and Sigmund Freud, who sent mankind on long
costly, wasteful, destructive pursuits,
that Einstein's General Relativity has not sent mankind
on a similar path, and wasted enormous amounts of time, money and
minds
on such pursuits as time travel, worm holes, gravitons,
warping through space, and the beginning and end
of the universe?
Is that what you are trying to tell me Sammy?
A mind is a terrible thing to waste.
Sam! Sam!
Are you suggesting that unlike the Jewish leaders and authors
responsible for writing and propagating the Torah,
and creating and propogating the Jesus myth,
and other Jewish writers like Nostradamus, Karl Marx
and Sigmund Freud, who sent mankind on long
costly, wasteful, destructive pursuits,
that Einstein's General Relativity has not sent mankind
on a similar path, and wasted enormous amounts of time, money and
minds
on such pursuits as time travel, worm holes, gravitons,
warping through space, and the beginning and end
of the universe?
Is that what you are trying to tell me Sammy?
A mind is a terrible thing to waste.
--
Are you suggesting that there was not
an enormous supply of "black holes"
and "dark matter" in the general area
of where Moses "parted the Red Sea",
or are you suggesting that the Jewish leaders and authors
responsible for reporting this,
were con men?
>>
>> Might want to work on that reading for comprehension there, Tom.
>>
>
> Are you suggesting that there was not
> an enormous supply of "black holes"
> and "dark matter" in the general area
> of where Moses "parted the Red Sea",
>
Eric is suggesting that you might want to work on that reading for
comprehension, Potter!
Since I mentioned neither of those, I'm going to say "no". Remember
what I said about reading for comprehension?
>
> or are you suggesting that the Jewish leaders and authors
> responsible for reporting this,
> were con men?
Since I didn't say this either, I'm going to say "no".
Try reading what is actually there, rather than what you want to be
there.
Well, no. Since it's the geometry wanks studying
curvature, which is where all the spontaneous
wavefunction deformation horseshit in physics comes from.
So the only thing you can do is vote for lasers, dvd+rw, and
medicaire recovery rules, and vote the morons out of office.
>
> I read the following somewhere:
>
> "An alternative way to conceive of gravity
> would of course be to follow the lead of
> other theories, and regard the gravitational
> field as simply a distribution of properties
> (the field strenghts) in flat spacetime.
> What ultimately makes this unattractive
> is that the distinctive properties of this
> spacetime would be completely unobservable,
> because all matter and fields gravitate. In
> particular, light rays would not lie on the "light
> cone" in a flat spacetime, once one incorporated
> the influence of gravity. It was ultimately the
> unobservability of the inertial structure of
> Minkowski space that led Einstein to eliminate it
> from his theory of gravitation and embrace the
> geometric approach."
>
> Questions.
>
> 1. Is gravity in flat spacetime means the same as
> force based gravity or is force based gravity another
> method where there is no spacetime but fixed space
> and time? If so, this means gravity in flat spacetime
> is fields based gravity in contrast to force based gravity?
>
> 2. How come light rays won't lie on the "light
> cone" in a flat spacetime gravity theory?
>
> 3. What is meant by the "unobservability of the inertial structure of
> Minkowski" that makes impossible gravity based on
> flat spacetime?
>
> 4. Is it totally impossible to model gravity that is not
> based on spacetime curvature? Maybe there is
> another way like perhaps the flat spacetime floating
> in brane surface, etc. What can you think of or
> maybe some creative folks have thought of it (pls.
> share it)?
>
> tnx.
>
> ralph
{ geometry } = { distribution of mass and energy }
However, it has had been added the lambda force along the geometrical side
of the equations, for the simple reason, that is a possible along the matter
and an energy side of the equation, which also would be as follows:
{ geometry } = { distribution of mass and energy } - { /\ energy }
{ geometry } = { distribution of mass and energy - /\ mass and /\ energy }
Therefore, that way the universe has had always contained a strange fluid
along a pressure which would be an equal matter to a minus its energy
density, whether the lambda tension would be as a negative, all this means a
simply, that the gravitational effect and how it does discourage any
approach, and this is what is all about, a definitely as a matter a fact.
--
Ahmed Ouahi, Architect
Best Regards!
<zzbu...@netscape.net> wrote in message
news:1184703033.1...@m37g2000prh.googlegroups.com...
Lasers wouldn't work if quantum mechanics is wrong.
[snip whining]
Theories do NOT make things work,
Nature does.
I assume that Gisse is suggesting that
LASERs would not have been invented,
if quantum mechanics was not around.
Charles Towne, the guy that invented the MASER,
which lead to LASERs, worked for Bell Labs
during WWII on centimeter microwave RADAR systems.
He learned that certain frequencies were not
useful for RADAR air search and bombing system,
because molecules in the atmosphere absorbed the energy.
He also learned that there was a need for
shorter wavelengths oscillators.
While attending a scientific committee meeting on
millimeter wave emissions in Washington, D.C.
Townes came up with the idea of using molecules as
millimeter wave resonators.
In other words, Townes, like all inventors,
was guided by his particular experience and needs,
not by some theory.
I suggest that if theory, rather than experience and need,
is the driving force, that Gisse sit down, and use his
knowledge of quantum mechanics to come up with
useful products.
--
Tom Potter
*** Time Magazine Person of the Year 2006 ***
*** May 2007 Anti-Bigot Award ***
http://home.earthlink.net/~tdp
http://tdp1001.googlepages.com/home
http://no-turtles.com
http://www.frappr.com/tompotter
http://photos.yahoo.com/tdp1001
http://spaces.msn.com/tdp1001
http://www.flickr.com/photos/tom-potter
http://tom-potter.blogspot.com
The fact remains that lasers would not work if quantum mechanics is
wrong.
[snip]
It is interesting to see that Gisse asserts that
"if quantum mechanics is wrong" in some way,
that LASERs and other effects successfully modeled by
quantum mechanics would cease to exist.
Scary eh?
If someone finds a flaw in the quantum mechanics model,
the whole universe disappears.
I suggest that governments MUST pass laws
to keep people from finding potential flaws in quantum mechanics
or else we are all doomed!