Reinventing cosmology: New research puts age of universe at 26.7 -- not 13.7 -- billion years
https://www.sciencedaily.com/releases/2023/07/230711133118.htm
quote:
"
Our universe could be twice as old as current estimates,
according to a new study that challenges the dominant cosmological model
and sheds new light on the so-called "impossible early galaxy problem.
"

On 12/07/2023 06:09, Jan Panteltje wrote:
>
> Reinventing cosmology: New research puts age of universe at 26.7 -- not 13.7 -- billion years
> https://www.sciencedaily.com/releases/2023/07/230711133118.htm
> quote:
> "
> Our universe could be twice as old as current estimates,
> according to a new study that challenges the dominant cosmological model
> and sheds new light on the so-called "impossible early galaxy problem.
> "

It could be but that is a long way from showing that it is.

Tired light is a very tired old theory and doesn't appear to hold over
the most well studied cosmological timescales. Invoking an additional
free parameter will always get you a better fit to the data but is
generally pretty meaningless unless it is absolutely needed.

The early formation of the first stars is surprising but not massively
so. Stellar lifetimes are also somewhat uncertain so it isn't surprising
with noise in the data that a few stars appear to be older than the
universe itself. Star lifetime is incredibly sensitive to the assumed
mass of the star or equivalently its absolute magnitude (ie. brightness
at a standard distance from the Earth). Tiny errors get magnified.

I expect they will be able to explain early galaxies as well once the
models become better. Models of the early universe are pretty impressive
but they are still imcomplete. The Webb telescope will help to tie
things down a lot since it can see a lot further out (aided and abetted
by Einstein rings providing super deep views near galaxy clusters).

Gravitational lensing provides a way to see the most incredibly distant
objects sometimes with as many as four views of the same object that
have taken different paths in spacetime to reach us. IOW they show the
object badly distorted in different places on the sky but with exactly
the same spectrum and if we are lucky with time delays between events.
If we get *really* lucky one of them will have a type I supernova go pop!

--
Martin Brown

On 12/07/2023 11:29, Anthony William Sloman wrote:
> On Wednesday, July 12, 2023 at 7:42:51 PM UTC+10, Martin Brown
> wrote:
>> On 12/07/2023 06:09, Jan Panteltje wrote:
>
> <snip>
>
>> The early formation of the first stars is surprising but not
>> massively so. Stellar lifetimes are also somewhat uncertain so it
>> isn't surprising with noise in the data that a few stars appear to
>> be older than the universe itself. Star lifetime is incredibly
>> sensitive to the assumed mass of the star or equivalently its
>> absolute magnitude (ie. brightness at a standard distance from the
>> Earth). Tiny errors get magnified.
>
> One of the things about the formation of the first stars is that
> there wasn't much in the way of elements heavier than hydrogen and
> helium (~25%) around. There was a little lithium, but not much.
>
> https://w.astro.berkeley.edu/~mwhite/darkmatter/bbn.html

Indeed although the traces of Lithium and other light metals play a very
important part in igniting the smaller stars. It is the lowest mass
stars that live the longest. Stellar lifetime scales as M^(-2.5)

To some extent I would prefer to believe that something about the
earliest stars was different to avoid having to invoke dark energy, but
I am told by my friends still in the game that isn't an adequate fixup.

IOW heavy stars burn incredibly bright for a short time and low mass
stars burn dimly for a very long time. Our sun is roughly half way
through its lifetime. Stars that survive from the very first star
formation must be under 1 solar mass to have lasted ~13Bn years.

> Stellar evolution presumably took a different path for the first
> stars, as they set about synthesising every element up to iron.

Enough to be able to see a difference in the spectra but not
significantly different in terms of being mostly hydrogen burning. Any
decent sized star quickly graduates to burning on the CNO cycle
irrespective of how much of those elements were present at the outset.

> They seem to have been big, so a supernova capable of synthesising
> elements heavier than iron would have shown up fairly early.
>
> https://webbtelescope.org/contents/articles/what-were-the-first-stars-like

Massive stars have brilliant but short lives - as little as 1 million
years so they would provide the raw materials for planets pretty
quickly. But there would be a distribution of sizes of stars formed.

--
Martin Brown

On a sunny day (Wed, 12 Jul 2023 10:42:41 +0100) it happened Martin Brown
<'''newspam'''@nonad.co.uk> wrote in <u8lsij$38egj$1@dont-email.me>:

>On 12/07/2023 06:09, Jan Panteltje wrote:
>>
>> Reinventing cosmology: New research puts age of universe at 26.7 -- not 13.7 -- billion years
>> https://www.sciencedaily.com/releases/2023/07/230711133118.htm
>> quote:
>> "
>> Our universe could be twice as old as current estimates,
>> according to a new study that challenges the dominant cosmological model
>> and sheds new light on the so-called "impossible early galaxy problem.
>> "
>
>It could be but that is a long way from showing that it is.
>
>Tired light is a very tired old theory and doesn't appear to hold over
>the most well studied cosmological timescales. Invoking an additional
>free parameter will always get you a better fit to the data but is
>generally pretty meaningless unless it is absolutely needed.
>
>The early formation of the first stars is surprising but not massively
>so. Stellar lifetimes are also somewhat uncertain so it isn't surprising
>with noise in the data that a few stars appear to be older than the
>universe itself. Star lifetime is incredibly sensitive to the assumed
>mass of the star or equivalently its absolute magnitude (ie. brightness
>at a standard distance from the Earth). Tiny errors get magnified.
>
>I expect they will be able to explain early galaxies as well once the
>models become better. Models of the early universe are pretty impressive
>but they are still imcomplete. The Webb telescope will help to tie
>things down a lot since it can see a lot further out (aided and abetted
>by Einstein rings providing super deep views near galaxy clusters).
>
>Gravitational lensing provides a way to see the most incredibly distant
>objects sometimes with as many as four views of the same object that
>have taken different paths in spacetime to reach us. IOW they show the
>object badly distorted in different places on the sky but with exactly
>the same spectrum and if we are lucky with time delays between events.
>If we get *really* lucky one of them will have a type I supernova go pop!

Yes,I was wondering this morning if our idea of what is out there is not totally wrong.
When we say 'universe' and 'that started as / with a big bang ...'
Somehow that does make me think of the sun orbits the earth and us always in the middle of everything
sort of dogma.

I am looking for a mechanism to explain things, Einstein's is just like Ohms law without electrons..
Fleming tube did away with it... :-)
So, let us take Le Sage type of gravity,
Seems gravity is measured to move at the same speed as light,
so: let's conclude it is transferred by the same particle, just a different state of it.
Now as to that size of the universe, that is silly
Even if there was a big bang there must have been zillions, elsewhere too,
and that universe is much bigger than we will ever be able to grasp.
But then why should not those Le Sage like particles lose energy over time?
There is your redshift
First question I had over Le Sage type particles: Where do / did those come from?
Big bang expanding force, other bangs?
We earth, are like an atom in a ? so big that talking about the start of it would
be like same atom arguing it was created in a big explosion that created everything.
It could have been, but then why not more bangs? as many more as there are stars in what we
now see, call our universe.
Thing is much much much bigger.,
And beyond that.
https://www.slashgear.com/nobel-prize-winner-says-the-universe-has-gone-through-multiple-big-bangs-10641825
Sir Roger Penrose is a mathematician and physicist from the University of Oxford, and he believes in the future there will be another Big Bang.
quote:
"He believes that there have been multiple Big Bangs and that more will happen.
Penrose points to black holes as holding clues to the existence of previous universes.
Sir Roger Penrose is a mathematician and physicist from the University of Oxford,
and he believes in the future there will be another Big Bang.
"
I did follow some of his lectures on youtube some years back.

On Wed, 12 Jul 2023 10:42:41 +0100, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:

>On 12/07/2023 06:09, Jan Panteltje wrote:
>>
>> Reinventing cosmology: New research puts age of universe at 26.7 -- not 13.7 -- billion years
>> https://www.sciencedaily.com/releases/2023/07/230711133118.htm
>> quote:
>> "
>> Our universe could be twice as old as current estimates,
>> according to a new study that challenges the dominant cosmological model
>> and sheds new light on the so-called "impossible early galaxy problem.
>> "
>
>It could be but that is a long way from showing that it is.
>
>Tired light is a very tired old theory and doesn't appear to hold over
>the most well studied cosmological timescales. Invoking an additional
>free parameter will always get you a better fit to the data but is
>generally pretty meaningless unless it is absolutely needed.
>
>The early formation of the first stars is surprising but not massively
>so. Stellar lifetimes are also somewhat uncertain so it isn't surprising
>with noise in the data that a few stars appear to be older than the
>universe itself. Star lifetime is incredibly sensitive to the assumed
>mass of the star or equivalently its absolute magnitude (ie. brightness
>at a standard distance from the Earth). Tiny errors get magnified.
>
>I expect they will be able to explain early galaxies as well once the
>models become better. Models of the early universe are pretty impressive
>but they are still imcomplete. The Webb telescope will help to tie
>things down a lot since it can see a lot further out (aided and abetted
>by Einstein rings providing super deep views near galaxy clusters).
>
>Gravitational lensing provides a way to see the most incredibly distant
>objects sometimes with as many as four views of the same object that
>have taken different paths in spacetime to reach us. IOW they show the
>object badly distorted in different places on the sky but with exactly
>the same spectrum and if we are lucky with time delays between events.
>If we get *really* lucky one of them will have a type I supernova go pop!

Can the multiple images be cross-correlated somehow? I guess the
delta-T is usually more than a human lifetime.

On 12/07/2023 14:24, John Larkin wrote:
> On Wed, 12 Jul 2023 10:42:41 +0100, Martin Brown
> <'''newspam'''@nonad.co.uk> wrote:
>
>> Gravitational lensing provides a way to see the most incredibly distant
>> objects sometimes with as many as four views of the same object that
>> have taken different paths in spacetime to reach us. IOW they show the
>> object badly distorted in different places on the sky but with exactly
>> the same spectrum and if we are lucky with time delays between events.
>> If we get *really* lucky one of them will have a type I supernova go pop!
>
> Can the multiple images be cross-correlated somehow? I guess the
> delta-T is usually more than a human lifetime.

It remains to be seen if we get one that is actively feeding with a hot
spot on its accretion disk. We might get lucky and see the same event 4
times. The time to orbit is supermassive black hole is not so huge so
when one swallows/rips apart a star we ought to see brightening.

The interesting thing is we get views of the same object at 3 or 4
different times but can't know what order they are in until something
changes abruptly.

One reason they imaged the BH in M87 first was that its black hole is
big enough that the brightness distribution on the sky doesn't change
significantly during the longish time of the observations.

They have caught M87 in the act of feeding quite recently with multiple
scale high resolution images. It has been known to have optical jets
almost since it was first discovered - sort of prototype quasar.

https://www.eso.org/public/news/eso2305/

That can't be said of the much smaller BH at the centre of our own
galaxy - it changes brightness on timescales of hours to days.

By sheer chance from our perspective in our spiral arm and viewed from
Earth they happen to appear about the same angular size on the sky.

--
Martin Brown

On Wed, 12 Jul 2023 15:48:56 +0100, Martin Brown
<'''newspam'''@nonad.co.uk> wrote:

>On 12/07/2023 14:24, John Larkin wrote:
>> On Wed, 12 Jul 2023 10:42:41 +0100, Martin Brown
>> <'''newspam'''@nonad.co.uk> wrote:
>>
>>> Gravitational lensing provides a way to see the most incredibly distant
>>> objects sometimes with as many as four views of the same object that
>>> have taken different paths in spacetime to reach us. IOW they show the
>>> object badly distorted in different places on the sky but with exactly
>>> the same spectrum and if we are lucky with time delays between events.
>>> If we get *really* lucky one of them will have a type I supernova go pop!
>>
>> Can the multiple images be cross-correlated somehow? I guess the
>> delta-T is usually more than a human lifetime.
>
>It remains to be seen if we get one that is actively feeding with a hot
>spot on its accretion disk. We might get lucky and see the same event 4
>times. The time to orbit is supermassive black hole is not so huge so
>when one swallows/rips apart a star we ought to see brightening.
>
>The interesting thing is we get views of the same object at 3 or 4
>different times but can't know what order they are in until something
>changes abruptly.
>
>One reason they imaged the BH in M87 first was that its black hole is
>big enough that the brightness distribution on the sky doesn't change
>significantly during the longish time of the observations.
>
>They have caught M87 in the act of feeding quite recently with multiple
>scale high resolution images. It has been known to have optical jets
>almost since it was first discovered - sort of prototype quasar.
>
>https://www.eso.org/public/news/eso2305/
>
>That can't be said of the much smaller BH at the centre of our own
>galaxy - it changes brightness on timescales of hours to days.
>
>By sheer chance from our perspective in our spiral arm and viewed from
>Earth they happen to appear about the same angular size on the sky.

I was thinking that one could observe multiple instances of
gravitational lensing and record intensity or spectra, and
cross-correlate to pick out the differing path lengths from lensing.
Some stars are noisy.

That wouldn't even have to be different images, which might be a
billion years of path difference. It could be done on bits of one
lensed image to get a usable time base.

On 12/07/2023 17:25, John Larkin wrote:
> On Wed, 12 Jul 2023 15:48:56 +0100, Martin Brown
> <'''newspam'''@nonad.co.uk> wrote:
>
>> On 12/07/2023 14:24, John Larkin wrote:
>>> On Wed, 12 Jul 2023 10:42:41 +0100, Martin Brown
>>> <'''newspam'''@nonad.co.uk> wrote:
>>>
>>>> Gravitational lensing provides a way to see the most incredibly distant
>>>> objects sometimes with as many as four views of the same object that
>>>> have taken different paths in spacetime to reach us. IOW they show the
>>>> object badly distorted in different places on the sky but with exactly
>>>> the same spectrum and if we are lucky with time delays between events.
>>>> If we get *really* lucky one of them will have a type I supernova go pop!
>>>
>>> Can the multiple images be cross-correlated somehow? I guess the
>>> delta-T is usually more than a human lifetime.
>>
>> It remains to be seen if we get one that is actively feeding with a hot
>> spot on its accretion disk. We might get lucky and see the same event 4
>> times. The time to orbit is supermassive black hole is not so huge so
>> when one swallows/rips apart a star we ought to see brightening.
>>
>> The interesting thing is we get views of the same object at 3 or 4
>> different times but can't know what order they are in until something
>> changes abruptly.
[snip]
> I was thinking that one could observe multiple instances of
> gravitational lensing and record intensity or spectra, and
> cross-correlate to pick out the differing path lengths from lensing.
> Some stars are noisy.

Although some stars are variable at the vast distances that are involved
in cosmology only a Type I supernova will do. They are essentially
standard candles that can for a few days or weeks outshine an entire
galaxy. Eventually we will see one in a gravitationally lensed system
and that will be very interesting for early universe theories.

This is the canonical Einstein cross image that fulfilled a GR
prediction of the magnifying effect of a foreground galaxy on a very
remote quasar almost exactly behind it.

https://science.nasa.gov/einstein-cross-gravitational-lens

Webb has done even better with this image:

https://www.livescience.com/james-webb-perfect-einstein-ring

The most remote objects ever seen are lensed by a suitably placed
galactic cluster (ie something with about 10-100 galaxies in it).
(the reference I was actually looking for)

https://www.space.com/james-webb-space-telescope-images-distorted-galaxies-gravitational-lensing-explained

Similar indirect observational methods are also being used to look for
behaviour that would characterise and otherwise invisible nearby smaller
BH crossing in front of a remote star.

> That wouldn't even have to be different images, which might be a
> billion years of path difference. It could be done on bits of one
> lensed image to get a usable time base.

Nothing is bright enough and the images are distorted in their own
peculiar ways.
It has to be a type I supernova (any supernova might still be a visible
change - but a type I immediately tells us its true brightness).

Mostly they end up squashed one way and stretched in the other - you
can't do much about the mass distribution that you are forced to look
through. The earliest deep Webb image showed several in the same field.

--
Martin Brown