Does Dark energy exist?

In article , Eric Flesch
writes:

On Sat, 28 Apr 12, Phillip Helbig wrote:
writes:
Yes, I know the static model has real problems with time dilation as a

Not just that, but there is also a stability problem.

That's an old chestnut, Phil, now well expired in the era of "dark
energy" a.k.a. the cormological constant which keeps things apart,
a.k.a. "accelerating expansion" in the FRW model, a.k.a.
"gravitational scalar" in the static model. The gravitational scalar
means there is an edge, or "lip", to gravitationally bound systems,
beyond which the ambient scalar rules. So no stability problem.

What you seem to be describing is the very first cosmological model
based on GR, Einstein's static model. It is STATIC in that it neither
expands nor contracts but it is not STABLE since it is mathematically
what is called an unstable fixed point, like a pencil balanced on its
tip. It has to be PERFECTLY balanced. Since our universe is not
EXACTLY homogeneous and isotropic, we know that it cannot be PERFECTLY
balanced.

Note also that Einstein's static model has POSITIVE spatial curvature.

Of course, there is no cosmological redshift in this model, so that
rules it out as well.

On Sun, 29 Apr 12, Phillip Helbig wrote:
What you seem to be describing is the very first cosmological model
based on GR, Einstein's static model. ...

No, Einstein's model had no extra-dimensional bulk. However, I wasn't
trying to present a model here. Whatever the merits, Haldane's view
that the universe is "queerer than we can suppose" is best, I think.
(But as an aside, there are papers from gr-qc on the bulk, but they
always treat the bulk as empty -- ludicrously.)

Science is in a funk these days, where each discipline is too keen to
enforce the "right" thinking, by awarding funding and tenure to the
"right" thinkers only. Who can get a astronomy degree or tenure. or
funding nowadays, advocating a static model? This isn't because it
can't be made to work -- it can. But it's starved of funding. The
only such funded theoreticians are in associated disciplines like
General Relativity & Quantum Cosmology or HEP, and even they are
careful to put an FRW context on their efforts, even though the static
alternatives are viable. In this way, however, cosmological progress
will come only from these outside disciplines. I hope I am wrong in
my pessimism, although happy to have progress from any quarter.

So currently the FRW parameters are being set by our SNIa
observations. These are the standard candles du jour, and we all love
standard candles. But that doesn't justify our use of them. Remember
how Cepheids turned out to have two separate populations. Now SN
observations show that there are two phases, first there is a
flare-dominated explosion, then a dust-and-debris dominated expansion.
The first part (given the SNIa model) should be quite standard but is
very brief and usually passes before we capture it, then the second
part has chaotic shrouding of the bright core by the expanding debris
-- so the SNIa is brighter or not depending on how shrouded it is in
our line of sight. So, not so "standard" a candle. But currently
nobody is worried about that, the paradigm is set, and everybody can
publish the latest observations using the SNIa standard candle. Maybe
in a few years the foundations will be thrown open to question -- I
actually saw an ArXiv paper about this a week or two ago, but
frustratingly can't find it now.

So my point, Phil, is that you speak with great certainty, and you
shouldn't. Cheers.

Eric

In article , Eric Flesch
writes:

Science is in a funk these days, where each discipline is too keen to
enforce the "right" thinking, by awarding funding and tenure to the
"right" thinkers only.

The 2011 Nobel Prize was awarded for something which went very much
the "right thinking" of the 1990s. I don't see the situation as
desperate as you paint it.

Who can get a astronomy degree or tenure. or
funding nowadays, advocating a static model? This isn't because it
can't be made to work -- it can.

If you know that, then why do you need funding? You can publish a paper
without funding.

So currently the FRW parameters are being set by our SNIa
observations.

Not only. The interesting thing is that one gets consistent results
from th SNIa on one hand and from other tests WITHOUT the SNIa on the
other.

Now SN
observations show that there are two phases, first there is a
flare-dominated explosion, then a dust-and-debris dominated expansion.
The first part (given the SNIa model) should be quite standard but is
very brief and usually passes before we capture it, then the second
part has chaotic shrouding of the bright core by the expanding debris
-- so the SNIa is brighter or not depending on how shrouded it is in
our line of sight. So, not so "standard" a candle. But currently
nobody is worried about that, the paradigm is set, and everybody can
publish the latest observations using the SNIa standard candle.

If this were a serious problem, then why does one get a good fit (in a
chi-square sense) for the m-z diagram for SNIa? If this were a serious
problem, one wouldn't expect to get ANY FLRW cosmological model, much
less one which agrees with other tests.

In article , Phillip
Helbig---undress to reply writes:

In article , Eric Flesch
writes:

Science is in a funk these days, where each discipline is too keen to
enforce the "right" thinking, by awarding funding and tenure to the
"right" thinkers only.

The 2011 Nobel Prize was awarded for something which went very much
the "right thinking" of the 1990s. I don't see the situation as
desperate as you paint it.

That should read "something which went very much AGAINST the".