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Jacob Navia

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Sep 15, 2022, 7:29:11 PM9/15/22
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The results of JWST are shaking the Big Bang model to its foundations. A
new article in Scientific American reports that a new cosmology needs to be
invented... See:
https://www.scientificamerican.com/article/jwsts-first-glimpses-of-early-galaxies-could-break-cosmology/

Yeah, the whole thing is coming down with a huge BANG!

But surely a new cosmology will appear, humans are like that. They need an
explanation of how all being arises, how the Universe started.

Four elephants sustain the universe proposed the Hindu researchers some
thousands of years ago. Well, that didn't pan out. What a surprise!

"In the beginning... " how many answers to that question have we invented?
The Big Bang goes to the same garbage bin that all other theories,
elephants included.

Personally, I do not know. I do not know what is life, even if I am a
biologist. I do not know my future, and the only sure fact that I do know
is my ignorance.

jacob

[[Mod. note --
It is very likely that 50 years from now our understanding of cosmology
will be different than it is today. It is also very likely that 50 years
from now our understanding of cosmology will in the main *refine* (as
opposed to overthrow) our understanding today.

This notion -- that scientific progress is mainly one of *refinement*
rather than over *overthrowing* -- is beaufully explained in Isaac Asimov's
classic essay "The Relativity of Wrong". Wikipedia has a brief synopsis
of this essay,
https://en.wikipedia.org/wiki/The_Relativity_of_Wrong#Title_essay
and there are lots of copies of the full essay online, e.g.,
https://hermiene.net/essays-trans/relativity_of_wrong.html
-- jt]]

Phillip Helbig (undress to reply)

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Sep 16, 2022, 6:31:02 PM9/16/22
to
I was going to recommend the same essay. In fact, I still recommend it!

As it happens, I am now at a conference on relativistic astrophysics.
No-one has mentioned JWST shaking the foundations of the big bang. I
remember being at conferences where soon after the respective events
the Higgs discovery was discussed, detection of gravitational waves, the
BICEP-2 result (which turned out to be wrong). Important results spread
throughout the community.

Of course JWST tells us things we didn't know before; if it didn't,
there would have been no reason to build it. But it certainly doesn't
question the foundations of the big bang. Some (tentative!!!!) results
might question some aspects of our understanding of the universe, but,
as noted in the essay, that is not the same as overthrowing the
foundations.

Also, 20 years ago, even though it is a popular-science magazine, I
wouldn't have hesitated pointing someone to a Scientific American
article. But in the last few years the quality of that magazine has
dropped enormously, almost to the point where one can say that if
something is claimed there, it is more likely to be wrong than right.

Phillip Helbig (undress to reply)

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Sep 18, 2022, 5:54:00 PM9/18/22
to
In article <d54fad3c-d53f-4b2a...@googlegroups.com>,
Jacob Navia <jacob...@gmail.com> writes:

> The results of JWST are shaking the Big Bang model to its foundations. A
> new article in Scientific American reports that a new cosmology needs to be
> invented... See:
> https://www.scientificamerican.com/article/jwsts-first-glimpses-of-early-galaxies-could-break-cosmology/

Let's look at that article in some detail.

"shocked astronomers" Yes, perhaps in some cases, though not necessarily
for the reasons you think.

"a mirage, or a revolution?" An open question (and probably a false
dichotomy).

"most distant starlight ever seen" OK, but doesn't contradict the big
bang. It would be a surprise is such a new, powerful instrument didn't
show us things farther away. We didn't notice a lack of things at the
limit of the Hubble Space Telescope, and it would be surprising indeed
if that limit happened to lie just beyond Hubble, so that JWST would
show nothing new.

Captain America sharing the study on Twitter is NOT the way to gauge the
importance of a paper.

Why was it beyond astronomers' wildest dreams? In the same paragraph,
the claim is that it was build to uncover never-before-seen details, to
revolutionize our understanding of the universe, both of which sound
like people didn't know what it would uncover. So true in some sense,
but not surprising.

Yes, some things were perhaps unexpected---but again, no contradiction
to the big bang.

The main problem with the article, or at least your interpretation of
it, seems to be conflating specific ideas of structure formation with
the idea of the big bang itself. Even if there is some uncertainty
about the former, that does not affect the latter, as the evidence for
it is very secure.

Bringing in Stacy McGaugh is a bad move. He advocates a non-standard
theory. Nothing wrong with that, but not they guy to interview here.
The article doesn't say how JWST's observations could support MOND, nor
what MOND predictions it confirmed. In any case, most MOND supporters
don't doubt the big bang.

"It's a bit too early to say we've completely broken the universe."
Indeed!

Peer review is NOT unfolding on Twitter, at least not peer review in the
conventional sense.

"Eschewing the traditional peer-review processes, which can take months,
many instead turned to publication on arXiv" displays a rather serious
lack of understanding. Most stuff on arXiv has been submitted to
peer-review journals, so a false dichotomy, and no eschewing involved.

> [[Mod. note --
> It is very likely that 50 years from now our understanding of cosmology
> will be different than it is today. It is also very likely that 50 years
> from now our understanding of cosmology will in the main *refine* (as
> opposed to overthrow) our understanding today.

Another good take on a similar theme:

@ARTICLE { MRees93a ,
AUTHOR = "Martin J. Rees",
TITLE = "Understanding the high-redshift
universe:~progress, hype and prospects",
JOURNAL = QJRAS,
YEAR = "1993",
VOLUME = "34",
NUMBER = "3",
PAGES = "279--289",
MONTH = sep
}

You can find the paper on ADS. If you don't know how to find a paper on
ADS, you should find out.

Gary Harnagel

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Dec 25, 2022, 2:29:49 AM12/25/22
to
[[Mod. note -- This article arrived at the s.a.r/s.p.r moderation
system on 2022-Dec-20. My apologes for the delay in processing it.
-- jt]]

> [[Mod. note --
> It is very likely that 50 years from now our understanding of cosmology
> will be different than it is today. It is also very likely that 50 years
> from now our understanding of cosmology will in the main *refine* (as
> opposed to overthrow) our understanding today.

Although "refinement" has been THE process for the past half-century,
"overthrow happened in 1905-1916 with the advent of relativity. It
happened again with quantum physics in the 1930's and the 1960's with
QFT. The discovery of "island universes" seems to have been more than a
"refinement" and the application of GR to cosmology was, too.

The problem with GR applied to cosmology is that theories such as the
FLRW metric aren't the only possibilities. If a "big bang" could happen
in our brane (taking a concept from M-theory), it may not have been
unique. Suppose a "big bang" happened before our present one and it's
way, way out there and expanding faster than we are. What would that
look like? It happened long, long ago so star formation has stopped.
All it would consist of would be red dwarfs, whose spectra might look
something like the CMBR. THAT would overthrow the FLRW model since all
of our big bang is not all that there is. There's other stuff out there
that has a gravitational effect on us, as well as spacetime itself.

It might also do away with FLRW's need for dark energy. GR predicts
that, since we are closer to this expanding side of the previous "big
bang," we would be dragged (accelerated) along its line of motion by the
Lense-Thirring effect, thus explaining dark energy.

The ekpyrotic theory of Steinhardt, Khoury, Turok and Ovrut, suitably
modified and verified, could do a GREAT deal of damage to our present
cosmological model. Whether this flight of fancy has any semblance of
reality, I think FLRW is in trouble.

Phillip Helbig (undress to reply)

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Dec 25, 2022, 3:55:39 AM12/25/22
to
In article <Y6fv4VgT...@gold.bkis-orchard.net>, Gary Harnagel
<hit...@yahoo.com> writes

> > [[Mod. note --
> > It is very likely that 50 years from now our understanding of cosmology
> > will be different than it is today. It is also very likely that 50 years
> > from now our understanding of cosmology will in the main *refine* (as
> > opposed to overthrow) our understanding today.
>
> Although "refinement" has been THE process for the past half-century,
> "overthrow happened in 1905-1916 with the advent of relativity. It
> happened again with quantum physics in the 1930's and the 1960's with
> QFT. The discovery of "island universes" seems to have been more than a
> "refinement" and the application of GR to cosmology was, too.

While I agree on the quantum stuff, I'm not so sure about the others.
There had been a debate on whether nebulae, as they were then known,
were within the Milky Way or extragalactic systems at least since the
time of William Herschel. The question was decided about a hundred
years ago, but since it was a decision between two alternatives which
had both been around for a while, I don't see it as a revolution in the
same sense as the quantum developments you mention. As to relativity,
with regard to special relativity I think that Rovelli makes a
convincing case that Einstein's formulation of it grew out of his
conservative attitude to physics (which, famously, led him to part
company with the quantum theory he helped to create). One could argue
that the results of SR were revolutionary, but the theory itself, so
Rovelli, really wasn't. He discusses this in his book about Anaximander
which, partly because we don't know much about Anaximander, is also
about many other things. With GR, I think that all agree that it was
revolutionary.

In general, though, the fact that there were some revolutions in the
past doesn't necessarily mean that there will be any in the future.

> The problem with GR applied to cosmology is that theories such as the
> FLRW metric aren't the only possibilities.

A Friedmann-Lemaître-Robertson-Walker (FLRW) model is a model a) based
on GR and b) homogeneous and isotropic. It can contain an arbitrary
number of components with various equations of state. Historically, and
probably physically as well, the most important have been
non-relativistic matter (known as "dust" in cosmology, where a dust
particle is a supercluster of galaxies), radiation, and the cosmological
constant. Due to the different equations of state, the respective
energy densities evolve differently with time, hence radiation is most
important at the beginning, then matter, then the cosmological constant.
But as you mention there are many other possibilities for cosmological
models based on GR.

50--100 years ago, homogeneity and isotropy were essentially simplifying
assumptions. Today, they are observational facts. (To be more exact,
we observe a high degree of isotropy which implies homogeneity unless we
are in a special location for which there is no evidence.)

> If a "big bang" could happen
> in our brane (taking a concept from M-theory), it may not have been
> unique. Suppose a "big bang" happened before our present one and it's
> way, way out there and expanding faster than we are. What would that
> look like? It happened long, long ago so star formation has stopped.
> All it would consist of would be red dwarfs, whose spectra might look
> something like the CMBR.

Regardless of the other points, the idea that the CMB is reprocessed
starlight is an old one, going back at least to Fred Hoyle who wanted to
have an explanation for the CMB in the steady-state model. The presence
of the CMB doesn't directly contradict the steady-state model (though in
that model its temperature would be constant while in conventional
cosmology it decreases with time, something which one could at least in
principle measure), but it is not something which arises naturally.
However, today so many details about the CMB are known that reprocessed
starlight is not a valid explanation. (By coincidence, the energy in
the CMB is about the same as that in starlight.)

> THAT would overthrow the FLRW model since all
> of our big bang is not all that there is. There's other stuff out there
> that has a gravitational effect on us, as well as spacetime itself.

Yes and no. Conceptually, yes. However, it is known that an FLRW model
is a good description of our Universe, and that would still be the case
even if the big picture were different.

> It might also do away with FLRW's need for dark energy. GR predicts
> that, since we are closer to this expanding side of the previous "big
> bang," we would be dragged (accelerated) along its line of motion by the
> Lense-Thirring effect, thus explaining dark energy.

Does that explanation work quantitatively?

I always wonder why people think that they have to explain dark energy.
GR has two physical constants, G and Lambda. Hardly anyone wants to
explain G in the same manner, i.e. explain why it is non-zero, calculate
its value from something else, and so on. That does not rule out that
dark energy might be something which behaves like the cosmological
constant (note that there is no evidence that dark energy---a more
general term---is anything more complicated that the cosmological
constant), but in that case one would have to explain why Lambda, the
"bare" cosmological constant, is zero. Usually if Nature has a degree
of freedom it is used and the absence of something like that, i.e. a
parameter being zero, implies a new symmetry, quantum number,
conservation law, etc., and the burden of proof is on those who make
that claim.

> The ekpyrotic theory of Steinhardt, Khoury, Turok and Ovrut, suitably
> modified and verified, could do a GREAT deal of damage to our present
> cosmological model.

Suffice it to say that it has not (yet?) convinced the community.
Again, a modified version would have to make concrete, testable
predictions for it to be verified (in the sense that none of those
predictions rule it out).

> Whether this flight of fancy has any semblance of
> reality, I think FLRW is in trouble.

Why do you think that FLRW is in trouble?

Gary Harnagel

unread,
Feb 12, 2023, 2:51:56 AMFeb 12
to
[[Mod. note -- I'm sorry for the delay in processing this article,
which arrived in the s.a.r moderation system on 2023-02-06, but was
mis-classified as spam by an over-eager spam filter.
-- jt]]

On Sunday, December 25, 2022 at 1:55:39 AM UTC-7, Phillip Helbig (undress t=
o reply) wrote:
>
> In article <Y6fv4VgT...@gold.bkis-orchard.net>, Gary Harnagel=20
> <hit...@yahoo.com> writes
> >
> > > [[Mod. note --=20
> > > It is very likely that 50 years from now our understanding of cosmolo=
gy=20
> > > will be different than it is today. It is also very likely that 50 ye=
ars=20
> > > from now our understanding of cosmology will in the main *refine* (as=
=20
> > > opposed to overthrow) our understanding today.=20
> >
> > Although "refinement" has been THE process for the past half-century,=
=20
> > "overthrow happened in 1905-1916 with the advent of relativity. It=20
> > happened again with quantum physics in the 1930's and the 1960's with=
=20
> > QFT. The discovery of "island universes" seems to have been more than a=
=20
> > "refinement" and the application of GR to cosmology was, too.
>
> While I agree on the quantum stuff, I'm not so sure about the others.=20
> There had been a debate on whether nebulae, as they were then known,=20
> were within the Milky Way or extragalactic systems at least since the=20
> time of William Herschel. The question was decided about a hundred=20
> years ago, but since it was a decision between two alternatives which=20
> had both been around for a while, I don't see it as a revolution in the=
=20
> same sense as the quantum developments you mention.

It seems to have made a big impact on our psyche. Evem those who believed
the "nebulae" were outside the galaxy, no one considered just how BIG the
universe is.

> As to relativity,=20
> with regard to special relativity I think that Rovelli makes a=20
> convincing case that Einstein's formulation of it grew out of his=20
> conservative attitude to physics (which, famously, led him to part=20
> company with the quantum theory he helped to create). One could argue=20
> that the results of SR were revolutionary, but the theory itself, so=20
> Rovelli, really wasn't. He discusses this in his book about Anaximander=
=20
> which, partly because we don't know much about Anaximander, is also=20
> about many other things. With GR, I think that all agree that it was=20
> revolutionary.=20
>=20
> In general, though, the fact that there were some revolutions in the=20
> past doesn't necessarily mean that there will be any in the future.

Perhaps not, but I wouldn't on that :-)

> > The problem with GR applied to cosmology is that theories such as the=
=20
> > FLRW metric aren't the only possibilities.
>
> A Friedmann-Lema=C3=AEtre-Robertson-Walker (FLRW) model is a model a) bas=
ed=20
> on GR and b) homogeneous and isotropic. It can contain an arbitrary=20
> number of components with various equations of state. Historically, and=
=20
> probably physically as well, the most important have been=20
> non-relativistic matter (known as "dust" in cosmology, where a dust=20
> particle is a supercluster of galaxies), radiation, and the cosmological=
=20
> constant. Due to the different equations of state, the respective=20
> energy densities evolve differently with time, hence radiation is most=20
> important at the beginning, then matter, then the cosmological constant.=
=20
> But as you mention there are many other possibilities for cosmological=20
> models based on GR.=20
>=20
> 50--100 years ago, homogeneity and isotropy were essentially simplifying=
=20
> assumptions. Today, they are observational facts. (To be more exact,=20
> we observe a high degree of isotropy which implies homogeneity unless we=
=20
> are in a special location for which there is no evidence.)
>
> > If a "big bang" could happen=20
> > in our brane (taking a concept from M-theory), it may not have been=20
> > unique. Suppose a "big bang" happened before our present one and it's=
=20
> > way, way out there and expanding faster than we are. What would that=20
> > look like? It happened long, long ago so star formation has stopped.=20
> > All it would consist of would be red dwarfs, whose spectra might look=
=20
> > something like the CMBR.
>
> Regardless of the other points, the idea that the CMB is reprocessed=20
> starlight is an old one, going back at least to Fred Hoyle who wanted to=
=20
> have an explanation for the CMB in the steady-state model. The presence=
=20
> of the CMB doesn't directly contradict the steady-state model (though in=
=20
> that model its temperature would be constant while in conventional=20
> cosmology it decreases with time, something which one could at least in=
=20
> principle measure), but it is not something which arises naturally.=20
> However, today so many details about the CMB are known that reprocessed=
=20
> starlight is not a valid explanation. (By coincidence, the energy in=20
> the CMB is about the same as that in starlight.)

I did a rough calculation taking the average spectra and occurrence of OBAF=
GKM.
It approximated a black-body distribution, so I don't see how it can be sai=
d that
it does't match the CMB if finer detail were considered. Do you have a ref=
erence
explaining why it doesn't match?

> > THAT would overthrow the FLRW model since all=20
> > of our big bang is not all that there is. There's other stuff out there=
=20
> > that has a gravitational effect on us, as well as spacetime itself.
>
> Yes and no. Conceptually, yes. However, it is known that an FLRW model=20
> is a good description of our Universe, and that would still be the case=
=20
> even if the big picture were different.

It assumes that there was ONE, and only one, big bang. Consequently, space=
time
has limited extent (e.g., one of many independent expanding bubbles in a su=
per-
structure). If the BB weren't unique to our universe, spacetime would not =
be
limited: we're tramping over "old" spacetime . That would have an impact o=
n the
assumptions one uses to construct a metric.

> > It might also do away with FLRW's need for dark energy. GR predicts=20
> > that, since we are closer to this expanding side of the previous "big=
=20
> > bang," we would be dragged (accelerated) along its line of motion by th=
e=20
> > Lense-Thirring effect, thus explaining dark energy.
>
> Does that explanation work quantitatively?=20

Don't know :-)

> I always wonder why people think that they have to explain dark energy.=
=20
> GR has two physical constants, G and Lambda. Hardly anyone wants to=20
> explain G in the same manner, i.e. explain why it is non-zero, calculate=
=20
> its value from something else, and so on.

It has always seemed ad hoc to me. It represents an unknown factor
that has some physical cause. When you solce a differential equation
and have arbitrary constant(s) of integration, they are determined by the
boundary conditions.

> That does not rule out that=20
> dark energy might be something which behaves like the cosmological=20
> constant (note that there is no evidence that dark energy---a more=20
> general term---is anything more complicated that the cosmological=20
> constant), but in that case one would have to explain why Lambda, the=20
> "bare" cosmological constant, is zero. Usually if Nature has a degree=20
> of freedom it is used and the absence of something like that, i.e. a=20
> parameter being zero, implies a new symmetry, quantum number,=20
> conservation law, etc., and the burden of proof is on those who make=20
> that claim.

Why couldn't it just be superfluous? Or, as you say, it is explained by
whatever dark energy turns out to be?

> > The ekpyrotic theory of Steinhardt, Khoury, Turok and Ovrut, suitably=
=20
> > modified and verified, could do a GREAT deal of damage to our present=
=20
> > cosmological model.
>
> Suffice it to say that it has not (yet?) convinced the community.=20
> Again, a modified version would have to make concrete, testable=20
> predictions for it to be verified (in the sense that none of those=20
> predictions rule it out).
>
> > Whether this flight of fancy has any semblance of=20
> > reality, I think FLRW is in trouble.
>
> Why do you think that FLRW is in trouble?

The JWST seems to be finding galaxies earlier than when they should
have formed, for one thing. Of course, "super-stars" are being hypothesize=
d
which evolve at extreme rates, so maybe things happened a lot faster then.
We'll see ....
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