Accelerating Universe theory dispels dark energy
Tweaking gravity does away with need for strange forces.
3 July 2003
JOHN WHITFIELD

The accelerating expansion of the Universe can be explained without
invoking a force of dark energy, a group of US physicists is proposing1.
Gravity alone might be driving everything apart with ever-increasing
speed, they claim.

"The fact that the Universe is speeding up might be the biggest mystery
in all of science," says Michael Turner of the University of Chicago.
"Really big problems require crazy new ideas - and ours is right up
there with the craziest." He hopes others will build on the idea, or
knock it down.

In Einstein's theory of general relativity, matter alters gravity by
curving space-time, like a bowling ball on a rubber sheet. Turner and
his colleagues have added a term to Einstein's equations that
strengthens as the Universe flattens.

The change has little effect on a young Universe, which is small,
tightly packed and curvy. But after ten billion years of spreading, the
new factor becomes powerful.

"We've blasphemed by changing Einstein's equations," says Turner. "The
reward is that we find the natural state of an empty Universe is
speeding up, and our Universe is getting emptier." The tweak to gravity
also explains cosmic inflation - the Universe's mushrooming in the
moments after the Big Bang.

Read the Rest as Nature Science Update
http://www.nature.com/nsu/030630/030630-7.html

Comment:
GR is not the right tool for modeling very large scale, at least not in
its original form. The evidence stacks up against it, but nobody seems
to be listening.

--
Kind Regards,
Robert Karl Stonjek.

"Jim Jastrzebski" wrote in message
...
"Robert Karl Stonjek" Message-id:


GR is not the right tool for modeling very large scale, at least not
in
its original form. The evidence stacks up against it, but nobody
seems
to be listening.

What evidence? (I'm listening)

-- Jim

Robert Karl Stonjek.

GR has made no large scale predictions that have come off thus far. The
shoehorn GR models into reality we have seen dark matter introduced,
dark energy, enormous tweaking of the cosmological constant, failure to
predict the accelerated expansion of the universe, failure to predict
the magnitude of the ripples in the background radiation (by a factor of
1,000 before COBE went up) etc etc.

GR does very well with objects and the space around those objects, but
does not do so well above the supercluser level.

--
Kind Regards,
Robert Karl Stonjek.

Robert Karl Stonjek wrote:
Accelerating Universe theory dispels dark energy
Tweaking gravity does away with need for strange forces.
3 July 2003
JOHN WHITFIELD

The accelerating expansion of the Universe can be explained without
invoking a force of dark energy, a group of US physicists is proposing1.
Gravity alone might be driving everything apart with ever-increasing
speed, they claim.

"The fact that the Universe is speeding up might be the biggest mystery
in all of science," says Michael Turner of the University of Chicago.
"Really big problems require crazy new ideas - and ours is right up
there with the craziest." He hopes others will build on the idea, or
knock it down.

In Einstein's theory of general relativity, matter alters gravity by
curving space-time, like a bowling ball on a rubber sheet. Turner and
his colleagues have added a term to Einstein's equations that
strengthens as the Universe flattens.

The change has little effect on a young Universe, which is small,
tightly packed and curvy. But after ten billion years of spreading, the
new factor becomes powerful.

"We've blasphemed by changing Einstein's equations," says Turner. "The
reward is that we find the natural state of an empty Universe is
speeding up, and our Universe is getting emptier." The tweak to gravity
also explains cosmic inflation - the Universe's mushrooming in the
moments after the Big Bang.

GR is perfectly capable of doing that without
tweak. It is called gravitational length
contraction. Actually, it is volume contraction,
since rods pointing in x, y and z direction will
all be shortened at the same time.

Assume our gravitational gamma = 1 billion =1e+9
suns radius = 2.215e+6 km
1 light-year = 9.467e+12 km
half distance nearest sun = 2.5 ly = 9.467e+12 km

The question is, do the suns touch each other when
gamma is reduced to one, like at the instant of
the big bang ?

Amply !
radius of sun @bb = 2.215e+14
2.5 light year = 2.367e+13

Our sun and proxima centauri would overlap by a
factor 10, by 1e+14 kilometers.

Of course, this is a rough calculation and the 1e9
billion gamma factor is based on the earth
generating one gravitational gamma.



Hayek.

"Robert Karl Stonjek" wrote in message
...

"The fact that the Universe is speeding up might be the biggest mystery
in all of science," says Michael Turner of the University of Chicago.

In the article you referenced it states: "In 1998, observations of exploding
stars showed that the Universe is expanding at an ever-increasing rate."
This article is based on the abstract at
http://xxx.lanl.gov/abs/astro-ph/0306438. That abstarct begins by stating:

"That the expansion of the Universe is currently undergoing a period of
acceleration now seems inescapable: it is directly measured from the
light-curves of several hundred type Ia supernovae, and independently
inferred from observations of the cosmic microwave background (CMB) by the
WMAP satellite and other CMB experiments."

I'd be curious to know how these observations could lead to "the fact" that
the expansion is "speeding up". It's difficult enough to quantitivly
determine the rate expansion itself let alone a change in that rate. I'm a
bit sceptical that we really can infer that the rate of expansion is
increasing from those supernova observations and CMB experiments. Calling it
a "fact" is going overboard.

raz

"RazroRog" wrote in message
...

"Robert Karl Stonjek" wrote in message
...

"The fact that the Universe is speeding up might be the biggest
mystery
in all of science," says Michael Turner of the University of
Chicago.

In the article you referenced it states: "In 1998, observations of
exploding
stars showed that the Universe is expanding at an ever-increasing
rate."
This article is based on the abstract at
http://xxx.lanl.gov/abs/astro-ph/0306438. That abstarct begins by
stating:

"That the expansion of the Universe is currently undergoing a period
of
acceleration now seems inescapable: it is directly measured from the
light-curves of several hundred type Ia supernovae, and independently
inferred from observations of the cosmic microwave background (CMB) by
the
WMAP satellite and other CMB experiments."

I'd be curious to know how these observations could lead to "the fact"
that
the expansion is "speeding up". It's difficult enough to quantitivly
determine the rate expansion itself let alone a change in that rate.
I'm a
bit sceptical that we really can infer that the rate of expansion is
increasing from those supernova observations and CMB experiments.
Calling it
a "fact" is going overboard.

raz

RKS:
It is my understanding that the accelerating expansion is generally
accepted.

As you say, "facts" on the large scale are tentative at best. But I
wonder....if the observations went the other way would cosmologists be
so cautious? After all, they expected the expansion of the universe to
be slowing - would we be speculating that the slowing observed is only a
slow period in an over all acceleration?

I think not. I think that evidence that supports current theories is
grasped all to readily and data that runs contrary is seen as
potentially flawed or transient or can be minimised in some other way.
How can science call itself objective if such biases exist? Why is
there no parallel non-big bang theory to contrast the big bang against?

If we made no wild assumptions, then the universe could be said to
appear to be expanding, but that's it. Assuming a big bang is a huge
leap of faith, as is imagining that their is a heaven just above the
clouds but slightly further than you can see (like super-strings) or
that lepricorns are real, but are not usually seen because they are just
very clever (like dark matter)

--
Kind Regards,
Robert Karl Stonjek.

"RazroRog" wrote in message
...

"Robert Karl Stonjek" wrote in message
...
It is my understanding that the accelerating expansion is generally
accepted.

Yes - I think it is. I'm just pretty amazed that the rate of a rate of
change can be infered when the rate itself is up for grabs. Probably
just my
ignorance of the particulars of the experiments.

As you say, "facts" on the large scale are tentative at best. But I
wonder....if the observations went the other way would cosmologists
be
so cautious? After all, they expected the expansion of the universe
to
be slowing - would we be speculating that the slowing observed is
only a
slow period in an over all acceleration?

I think not. I think that evidence that supports current theories
is
grasped all to readily and data that runs contrary is seen as
potentially flawed or transient or can be minimised in some other
way.
How can science call itself objective if such biases exist? Why is
there no parallel non-big bang theory to contrast the big bang
against?

Even top-notch physicists have their own pet notions and will attempt
to do
some fancy footwork for their defense. Witness Einstein's cosmological
constant or the degree that Fred Hoyle went to fit his Steady State
cosmology to observation. It's understandable though. Science is not
totally
objective. There is no such thing. Especially when we are talking
about
human minds creating models of the subtleties of physical reality and
the
problems inherent in not only observing those subtleties but
interpretting
them as well. Still, science has enhanced or understanding of our
physical
environment better than any other discipline that I know. I doubt we'd
be
able to calculate relativistically corrected GPS satellite
trajectories by
Philosophy or Religion.

If we made no wild assumptions, then the universe could be said to
appear to be expanding, but that's it. Assuming a big bang is a
huge
leap of faith, as is imagining that their is a heaven just above the
clouds but slightly further than you can see (like super-strings) or
that lepricorns are real, but are not usually seen because they are
just
very clever (like dark matter)

There is a valid place for conjecture in physics. Some have panned out
later
as technology has allowed for more precise measurements. Some haven't.
Some
can probably never be tested in full. I can't see us ever bulding a
particle
accelerator that can test theories dealing with energies that have
been
calculated in the very early Universe. Many can be tested in part
though as
more clever ways of dealing with the experimental side of physics
advances.
As an example, it took how many years before the Aspect experiments
showed
the reality EPR effects? The wisdom comes in separating wild
speculation and
buffoon science from the credible. There's a gray area in there for
sure.

raz

RKS:
I'm all for conjecture, it is an essential step. Back filling from the
secure theoretical point so achieved by some estimates, approximations
and conjecture is more common than some scientific revisionists would
care to admit. But when we branch off into areas where there is no
possibility of actual measurement, then conjecture should be a process
of bifurcation with scientific advocates for both branches.

The accelerated expansion was discovered by observing around 80 type 1a
supernovas at around 7 billion light years distance. The local
expansion rate at the distance (the speed at which galaxies recede from
each other) is slower than it is locally (near us). As the distant
galaxies represent the past, then the expansion rate must have been
slower in the past.

Apart from the supernova observations, Bahcall and Fan of Princeton Uni,
studying massive galaxy clusters several billion light years from Earth
came, to the same conclusion (in 1998). When two studies using
different methods both come to the same conclusion at the same time it
is either a conspiracy or good science. I come down on the side of good
science

This finding should have bolstered the cosmological theory or model
which made some opposite assumptions to the Big Bang. Opposing theories
keep both sides honest and motivated. One unproven theory is more like
a belief system with new findings, regardless of whether they agree or
disagree with the model, need to be "explained". Religionists are still
doing exactly that today - for instance explaining why vehicles can fly
to where heaven was supposed to be (at one time, people believed that
they could catch glimpses of angels in the clouds).

One of the biggest assumptions made by the Big Bang theory is that the
entire universe had a single common past. The assumption is that
regardless of where you place an observer in the universe, the same past
may be inferred from measurement and observation. But if you were to
place your observer on the surface of a Black Hole or on the back of a
photon traversing the entire universe, no such observation or
measurement would be made.

--
Kind Regards,
Robert Karl Stonjek.

Robert Karl Stonjek wrote:

Accelerating Universe theory dispels dark energy
Tweaking gravity does away with need for strange forces.
3 July 2003
JOHN WHITFIELD

The accelerating expansion of the Universe can be explained without
invoking a force of dark energy, a group of US physicists is proposing1.
Gravity alone might be driving everything apart with ever-increasing
speed, they claim.

"The fact that the Universe is speeding up might be the biggest mystery
in all of science," says Michael Turner of the University of Chicago.
"Really big problems require crazy new ideas - and ours is right up
there with the craziest." He hopes others will build on the idea, or
knock it down.

In Einstein's theory of general relativity, matter alters gravity by
curving space-time, like a bowling ball on a rubber sheet. Turner and
his colleagues have added a term to Einstein's equations that
strengthens as the Universe flattens.

The change has little effect on a young Universe, which is small,
tightly packed and curvy. But after ten billion years of spreading, the
new factor becomes powerful.

"We've blasphemed by changing Einstein's equations," says Turner. "The
reward is that we find the natural state of an empty Universe is
speeding up, and our Universe is getting emptier." The tweak to gravity
also explains cosmic inflation - the Universe's mushrooming in the
moments after the Big Bang.

Read the Rest as Nature Science Update
http://www.nature.com/nsu/030630/030630-7.html

Comment:
GR is not the right tool for modeling very large scale, at least not in
its original form. The evidence stacks up against it, but nobody seems
to be listening.



The article that you're quoting describes a minor modificationof the
Einstein Field Equations that generalizes GR but is
interpreted in the same way as the original theory.

This isn't GR, but it is a natural generalization of it.

John Anderson

"Robert Karl Stonjek"
Message-id:

[Robert]
GR is not the right tool for modeling very large scale,
at least not in its original form. The evidence stacks
up against it, but nobody seems to be listening.

[Jim]
What evidence? (I'm listening)

[Robert]
GR has made no large scale predictions that have come
off thus far. The shoehorn GR models into reality we have
seen dark matter introduced, dark energy, enormous
tweaking of the cosmological constant, failure to predict
the accelerated expansion of the universe, failure to
predict the magnitude of the ripples in the background
radiation (by a factor of 1,000 before COBE went up)
etc etc.

GR does very well with objects and the space around
those objects, but does not do so well above the
supercluser level.

Your brand of GR depends on your spacetime metric.
A metric based on the principle of conservation of
energy (unlike 'big bang' metric) predicted "accelerating
expansion" and "anomalous" acceleration of space
probes in 1985 but it was too early and so all referees
said "must not be published" (now editors say: OK but
of too little interest to physicists so it doesn't need to
be published).

So you are left with GR that predicts decelerating
expansion and can't explain behavior of Pioneers
and is trying to add epicycles to explain what it
can't, possibly because energy, contrary to popular
opinion, can't be created (surprise, surprise). It
justifies your doubts whether GR works. It does
work, just put conservation of energy back into it or
at least lobby for allowing to publish papers that
assume that energy can't be created from nothing
and therefore predict a stationary universe and
how "accelerating expansion" is simulated in it.
If you need predicted numbers, the density of this
universe is ~6x10^(-27) kg/m^3, acceleration of
expansion is ~2.5x10^(-36) s^(-2), "anomalous"
acceleration of Pioneers ~7x10^(-10) m/s^2. If
you need the theoretical value of Hubble's constant
it comes out accidentally as c/R, where R is
"Einstein's radius". Too bad physicists are not
interested how it all is derived as editors of Phys.
Rev. Letters tell me for 18 years. I hope they will
one day just need more trouble with their present
pet theories.

-- Jim

"Jim Jastrzebski" wrote in message
...
"Robert Karl Stonjek"
Message-id:

[Robert]
GR is not the right tool for modeling very large scale,
at least not in its original form. The evidence stacks
up against it, but nobody seems to be listening.

[Jim]
What evidence? (I'm listening)

[Robert]
GR has made no large scale predictions that have come
off thus far. The shoehorn GR models into reality we have
seen dark matter introduced, dark energy, enormous
tweaking of the cosmological constant, failure to predict
the accelerated expansion of the universe, failure to
predict the magnitude of the ripples in the background
radiation (by a factor of 1,000 before COBE went up)
etc etc.

GR does very well with objects and the space around
those objects, but does not do so well above the
supercluser level.

Your brand of GR depends on your spacetime metric.
A metric based on the principle of conservation of
energy (unlike 'big bang' metric) predicted "accelerating
expansion" and "anomalous" acceleration of space
probes in 1985 but it was too early and so all referees
said "must not be published" (now editors say: OK but
of too little interest to physicists so it doesn't need to
be published).

That IS fascinating. There is nothing wrong with GR per se - I was
being a bit too general. It is what has been done with GR and in the
name of GR that causes problems and undermining the predictive power and
reliability of GR for large scale phenomena (large in space and in
time).

GR has enough flexibility to "accommodate" a number of theories, but it
seems, and you seem to be confirming it here, that only one line, the
Big Bang model of the day, gets into press. There are solutions which
have no Big Bang at all, but I doubt that we will hear of them from
credible sources.

In the simplest form of expansion as explained in low level books, the
further apart objects are the faster is their recession speed.
Therefore the recession speed must have been slower in past. I have not
seen anything that refutes the obvious.

So you are left with GR that predicts decelerating
expansion and can't explain behavior of Pioneers
and is trying to add epicycles to explain what it
can't, possibly because energy, contrary to popular
opinion, can't be created (surprise, surprise). It
justifies your doubts whether GR works. It does
work, just put conservation of energy back into it or
at least lobby for allowing to publish papers that
assume that energy can't be created from nothing
and therefore predict a stationary universe and
how "accelerating expansion" is simulated in it.
If you need predicted numbers, the density of this
universe is ~6x10^(-27) kg/m^3, acceleration of
expansion is ~2.5x10^(-36) s^(-2), "anomalous"
acceleration of Pioneers ~7x10^(-10) m/s^2. If
you need the theoretical value of Hubble's constant
it comes out accidentally as c/R, where R is
"Einstein's radius". Too bad physicists are not
interested how it all is derived as editors of Phys.
Rev. Letters tell me for 18 years. I hope they will
one day just need more trouble with their present
pet theories.

-- Jim

RKS:
Last density numbers I played with was 1~2E-27 ('E' for exponential
(10^x) in Visual Basic) when I wondered if the universe might really be
a Schwarzschild black hole (closed).

When you say energy can't be created, are you including the new "Dark
Energy". I sometimes wonder if cosmologists are yet to rise above Harry
Potter.

--
Kind Regards,
Robert Karl Stonjek.

"Robert Karl Stonjek"
Message-id:

A metric based on the principle of conservation of
energy (unlike 'big bang' metric) predicted "accelerating
expansion" and "anomalous" acceleration of space
probes in 1985 but it was too early and so all referees
said "must not be published" (now editors say: OK but
of too little interest to physicists so it doesn't need to
be published).

That IS fascinating. [...]

If you think so I may tell you briefly how it has been
done and what is the main difference wrt the "big
bang" cosmology.

The "big bang" cosmology assumes that g_ik tensor
of Einstein's Field Equations is a symmetric tensor
(and that it is "metric tensor" of the spacetime: it
is a tensor that produces "metric", the product
g_ik x^i x^k, normally called ds^2). It looks good at
the first sight and so it has been generally accepted
by majority (perhaps all) cosmologists.

On the second sight though it turns out that such a
metric (produced by symmetric g_ik) can't produce
Hubble's redshift in a stationery universe, since
symmetry of g_ik assures that light signals are time
reversible, i.e. if light has redshift one way it has
the same blueshift the other way along certain path.
The next conclusion is that if photon moved from A
to B and then back (from B to A) it would come back
to A with the same energy it left A (as in Newtonian
physics where photons are not visible gravitationally
and the gravitational field is conservative).

Yet in Einsteinian physics photons contribute to
"gravitational field" and so they are not invisible
gravitationally. It means they cause (tiny)
disturbance in the "gravitational field" and so going
from A to B they would come to B with less energy
than in purely Newtonian world, losing part of their
energy for creating gravitational disturbance (moving
masses around them and "pumping" energy into them if
they moved back and forth, making those masses
oscillate). And so coming back (from B to A) they
would came with even less energy.

This picture with "gravitational field" is a Newtonian
picture, adjusted for relativistic effects of photons
contributing to the "field". It suggests "tired light
effect", but since in Einsteinian gravity (real world)
there are no forces acting on photons the photons
can't get tired so the mechanism of "loss of energy"
or rather relativistic counterpart of this Newtonian
effect has to be relativistic (not some "force") and
therefore it should be built into the metric of the
spacetime.

There are (at least) two possible solutions:
(1) ignore the effect and leave the g_ik tensor
symmetric, which might be justifiable if the effect is
negligible, and this is way adopted by "big bang"
cosmology, unfortunately without any estimation of the
magnitude of the effect, and so by an assumption of
(slight) violation of conservation of energy (and that
is why "big bang" cosmologists maintain that "energy is
not conserved in general relativity", and (2) by
treating everything rigorously by assuming non symmetric
g_ik tensor, which allows for "loss" of photon's energy
(in Newtonian approximation) around closed loops.

Calculation of this "lost" energy, that would correspond
to Hubble's redshift is very simple: just take a flat
sheet of photons (plane), move it in a universe of
certain mass density, and calculate "created" Newtonian
"potential energy" while this sheet of photons moves.
Then subtract this energy from energy of photons.
The result is that then in such universe we would see
Hubble's redshift with Hubble's constant H=c/R, where
c is speed of light and R is accidentally "Einstein's
radius of the universe". This is where the density of
the universe 6E-27 kg/m^3 comes from, since then Hubble's
constant comes out as 70 km/s/Mpc (about what is observed).

It also says that on any moving object acts a Newtonian
"drag", called in astronomy "dynamical friction", equal
c^2/R, which then would be around 7E-10 m/s^2, about
what Pioneers experience as "anomalous" acceleration.

Since the Hubble's redshift then has an exponential
dependency on distance, the apparent expansion that this
effect produces looks like accelerating with acceleration
((c/R)^2)/2, for our universe about 2.5E-36 s^-2
(unfortunately too early to tell with any certainty if
this is what is observed).

The metric that produces all the above things (since
GR has to explain gravitational phenomena with proper
metric) is (for one spatial coordinate r, and for c=1)
ds^2=exp(-2r/R)dt^2+2sinh(2r/R)dtdr-exp(2r/R)dr^2.

This brand of GR is kept secret since 1985 (not by me
obviously, but by editors of scientific journals who
apparently don't want to make waves). IMHO it is quite
good stuff and since it explains a lot of observed
things that so far don't have any other explanation
it might be worth publishing and at least worth of some
discussion. Not many people are interested though.
The editors tell me that their readers surely wouldn't be.
Everyone seems very happy with the expanding universe.
Which means the time didn't come yet for a change of
how we imagine the universe.

-- Jim

Robert Karl Stonjek