Geometry of Look-Back

In article , Steve Willner
writes:

That this yields that the most distant SNe have sub-par
luminosities seems to ring no alarm bells amongst the researchers.

Introducing an non-zero cosmological constant, when nearly everyone
up to then was convinced it was zero, isn't an "alarm bell?"

Indeed!

Note also that the currently favoured value for the cosmological
constant predicts not just a dimming with redshift but, at large
redshift, a brightening. This is a very specific prediction, and hard
to get from other models of the dimming.

One of the models that I'm juggling treats time dilation as the
square root of the redshift,

Is there any physical motivation for this? There is a very clear
physical motivation for multiplying by (1+z).

It would take some
searching around to find more light curves, but quite a few are
available. You could probably get more if you asked for them.

These days, it isn't possible to publish all data in a paper journal.
However, probably most of the stuff is available, even back to the raw
data, either by asking or due to some observatory policy which makes all
data public after a certain time. Since only a minority need such data,
and when they do, probably in electronic form, I think it is OK not to
publish it conventionally.

On Sat, 22 Dec 12, Phillip Helbig wrote:
I wrote:
One of the models that I'm juggling treats time dilation as the
square root of the redshift,

Is there any physical motivation for this?

Yes, one model of "geometry of look-back" is that we see the past as
smaller and slower than the present, because of the drift of a (new)
cosmological factor. This maps into seeing the nightsky as an
open-manifold universe with a redshift. So this proposes to swap this
one new cosmological factor for all of yours (dark energy, etc, you
know what they all are).

But I have to well-fit this to all observations, which is daunting for
me, since so much observational data is published only as
post-FRW-processed data, which is hard for me to decode backwards. I
may indeed have to do as you and Steve Willner kindly suggest, which
is to request the original data from the authors.

I remind all that the usual riposte to the "many worlds" advocates is
that we prefer to economize on universes. Similarly, I wish to
economize on all the magic tropes of modern cosmology, and remind all
that things flying apart at high speed is no way to model a universe.

And happy holidays! :-)

In article , Eric Flesch
writes:

One of the models that I'm juggling treats time dilation as the
square root of the redshift,

Is there any physical motivation for this?

Yes, one model of "geometry of look-back" is that we see the past as
smaller and slower than the present, because of the drift of a (new)
cosmological factor.

Unless there is some physical motivation for this OTHER THAN explaining
the observations, this seems a rather ad-hoc solution.

This maps into seeing the nightsky as an
open-manifold universe with a redshift. So this proposes to swap this
one new cosmological factor for all of yours (dark energy, etc, you
know what they all are).

All? The only thing remotely strange is dark energy, better known as
the cosmological constant, and mathematically that has been around for
100 years. Interesting that when observations indicated a slightly more
complicated universe, it turned out that 1920s cosmology already had a
solution. Dark matter? If that is strange, then that means that the
default assumption is that all matter glows, which seems strange to say
the least. Non-baryonic matter, meaning most of the universe is made
out of something we are not? Is that strange? Most of the matter we
know about is in stars, but we ourselves are not stars, and no-one finds
that strange.

But I have to well-fit this to all observations, which is daunting for
me, since so much observational data is published only as
post-FRW-processed data, which is hard for me to decode backwards.

Not only that, but often interpreted in the light of a certain FRW
model.

I
may indeed have to do as you and Steve Willner kindly suggest, which
is to request the original data from the authors.

I don't think that will be a problem. Many data are available today
even without asking---usually not directly in publications, but in
online resources mentioned there.

Similarly, I wish to
economize on all the magic tropes of modern cosmology,

Again, modern cosmology is surprisingly boring. Recently, the 9-year
WMAP papers appeared on arXiv. A huge amount of data, and no
indications that we need to revise our cosmological model. In
particular, the large-scale model is, again, 1920s cosmology.

and remind all
that things flying apart at high speed is no way to model a universe.

Unless you have a really, really, really different theory of gravity,
you have to explain the stability of the universe if it is not flying
apart.

In article ,
Phillip Helbig---undress to reply writes:
Unless you have a really, really, really different theory of gravity,
you have to explain the stability of the universe if it is not flying
apart.

Collapsing would be OK, too. Phillip knows that but didn't mention
it because it's contrary to observations. The point is that a static
universe might be in equilibrium, but it is unstable unless one puts
in new physics. Of course we've seen weird physics turn out to be
right in some cases (QM comes to mind!), but GR works so well on
small scales that new physics in that realm looks unlikely.
Nevertheless, if a new model fits the data (and isn't grossly
contrived with a huge number of free parameters), I'd expect people
to consider it.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA

On Thu, 03 Jan 13 07:35:24 GMT, Steve Willner wrote:
Phillip Helbig---undress to reply writes:
you have to explain the stability of the universe if it is not flying apart.

The point is that a static universe might be in equilibrium, but it is
unstable unless one puts in new physics.

It's not hardly new physics anymore to model the universe as a 4-space
embedded into an n-space, or specifically as an onion peel onto a
spherical 5-or-6-space. This confers stability via the surface
tension and orthonormal gravitational scalar of the bulk, ie,
Einstein's constant..

Nevertheless, if a new model fits the data (and isn't grossly
contrived with a huge number of free parameters), I'd expect people
to consider it.

The only part of FRW I have no answer to is the observed increase of
CMB temperature with look-back time -- that kills any static model
stone-cold dead -- except that a case for publication bias can be
made here, which I've discussed in the other thread. This includes
the question of how much our expectations bias our results, a- la
Millikan oil drop experiments. This is a broad unquantified topic
that normally one would want to avoid.

In article ,
Eric Flesch writes:
It's not hardly new physics anymore to model the universe as a 4-space
embedded into an n-space, or specifically as an onion peel onto a
spherical 5-or-6-space. This confers stability via the surface
tension and orthonormal gravitational scalar of the bulk, ie,
Einstein's constant..

I have no problem with the basic idea, of course. What I don't
understand is how this leads to stability and not merely an unstable
equilibrium.

The only part of FRW I have no answer to is the observed increase of
CMB temperature with look-back time

If the model is static, where does evolution come from? Or
equivalently, why does the Universe have a finite age? Also, what
about SN light curves slowing with redshift?

No hurry to answer before you have worked out more details and are
ready to explain, but these will be obvious questions.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA

On Thu, 03 Jan 13, Steve Willner wrote:
Eric Flesch writes:
... the universe as a 4-space embedded into an n-space, or
specifically as an onion peel onto a spherical 5-or-6-space. This
confers stability via ... gravitational scalar of the bulk

I have no problem with the basic idea, of course. What I don't
understand is how this leads to stability and not merely an unstable
equilibrium.

Pretty much all such gr-qc work is done assuming a void bulk. Talk
about an elephant in the room! If we fill the bulk with n-space
matter & energy, so we are just a sub-universe of the larger universe,
then stability follows as naturally as the stability of standing on
the Earth. Also this allows for galaxies to be spigotted from the
bulk, so no more mystery about matter erupting from galaxy centres,
the "bar" of bar spirals, etc.

If the model is static, where does evolution come from? Or
equivalently, why does the Universe have a finite age? Also, what
about SN light curves slowing with redshift?

No hurry to answer before you have worked out more details and are
ready to explain, but these will be obvious questions.

The idea is that these are artefacts of the queerness of look-back
plus our models built on clay feet. And you're absolutely right, I
can be in no hurry to give a proper answer until I have worked it all
out into a well-fitting whole. How long will that take an amateur
like me. Months? Years? So thanks for your help in clarifying this
task, cheers. Eric

In article , Eric Flesch
writes:

... the universe as a 4-space embedded into an n-space, or
specifically as an onion peel onto a spherical 5-or-6-space. This
confers stability via ... gravitational scalar of the bulk

Pretty much all such gr-qc work is done assuming a void bulk. Talk
about an elephant in the room! If we fill the bulk with n-space
matter & energy, so we are just a sub-universe of the larger universe,
then stability follows as naturally as the stability of standing on
the Earth. Also this allows for galaxies to be spigotted from the
bulk, so no more mystery about matter erupting from galaxy centres,
the "bar" of bar spirals, etc.

The idea is that these are artefacts of the queerness of look-back
plus our models built on clay feet. And you're absolutely right, I
can be in no hurry to give a proper answer until I have worked it all
out into a well-fitting whole. How long will that take an amateur
like me. Months? Years? So thanks for your help in clarifying this
task, cheers. Eric

What is the motivation? There is nothing wrong with a non-static
universe, and you seem to be introducing additional complexity to
explain something which doesn't need explaining. Not necessarily wrong,
of course, but Occam would not approve. If, of course, there were
things the standard model couldn't explain, then that would be
motivation, but I don't see any. WMAP could have shown some surprises,
but didn't. We'll see what Planck has in store.

In article , Eric Flesch
writes:

The only part of FRW I have no answer to is the observed increase of
CMB temperature with look-back time -- that kills any static model
stone-cold dead -- except that a case for publication bias can be
made here, which I've discussed in the other thread. This includes
the question of how much our expectations bias our results, a- la
Millikan oil drop experiments. This is a broad unquantified topic
that normally one would want to avoid.

I don't think you've made a very convincing case here. As I pointed
out, publication bias can cut the other way too. Also, consider that
you know about the late publication of one paper. If you believe
publication bias is so rampant, then think of all the stuff you don't
know about. :-) Also, make sure that YOU don't have a bias here, i.e.
that you aren't giving too much weight to one paper and too little to
several others.

On Thu, 03 Jan 13, Phillip Helbig wrote:
I don't think you've made a very convincing case here.

Absolutely right. I haven't laid out anything comprehensive because
it's not ready and I did say a couple times that my goal was to
present it in the early 2013 if I could sort out the issues. These
discussion have helped to sort out individual issues.

If you believe publication bias is so rampant, then think of all
the stuff you don't know about. :-)

Right again, and that applies to us all.

Also, make sure that YOU don't have a bias here, i.e.
that you aren't giving too much weight to one paper and too little to
several others.

Exactly, for me to state that the dependency of CMB temperature with
redshift is ill-founded, I need to read the whole literature on that
topic. A big ask for an amateur like me, with limited time available.
Which is why I can't be more definitive or convincing at this time, or
maybe any time soon. But thanks for the helpful discussions.

Eric