Cosmologists intrigued by signs the universe might stop expanding; influence of dark energy may be weakening

[essentialsaltes]

The fate of the universe is still very much up in the air.

Right now it is expanding, at an accelerating rate. If nothing changes, many billions or trillions of years from now the universe would presumably become cold, dark and inhospitable.

But new data posted online Wednesday by scientists with the Dark Energy Spectroscopic Instrument (DESI) survey suggest this process of cosmic acceleration — attributed to a mysterious energy field dubbed “dark energy” — has been weakening over the past 4 billion to 5 billion years.

Dark energy is the primary driver of [the universe's future], but if that mysterious energy field decays, matter and gravity could become the dominant factors, he said. [Which could tip us back into a Big Crunch rather than a Big Rip]

DESI, funded by the Department of Energy’s Office of Science and managed by the Lawrence Berkeley National Laboratory, is an international collaboration involving 900 researchers and 70 institutions worldwide. The experiment uses a telescope at Kitt Peak in Arizona to map the history of the universe. Its dataset includes 13.1 million galaxies and 1.6 million quasars, which are very bright, distant objects powered by supermassive black holes.

 

[AV1611VET]

Yup.

I knew the universe was going to stop expanding since I was a kid.

 

[SelfSim]

The fate of the universe is still very much up in the air.

Right now it is expanding, at an accelerating rate. If nothing changes, many billions or trillions of years from now the universe would presumably become cold, dark and inhospitable.

But new data posted online Wednesday by scientists with the Dark Energy Spectroscopic Instrument (DESI) survey suggest this process of cosmic acceleration — attributed to a mysterious energy field dubbed “dark energy” — has been weakening over the past 4 billion to 5 billion years.

Dark energy is the primary driver of [the universe's future], but if that mysterious energy field decays, matter and gravity could become the dominant factors, he said. [Which could tip us back into a Big Crunch rather than a Big Rip]

DESI, funded by the Department of Energy’s Office of Science and managed by the Lawrence Berkeley National Laboratory, is an international collaboration involving 900 researchers and 70 institutions worldwide. The experiment uses a telescope at Kitt Peak in Arizona to map the history of the universe. Its dataset includes 13.1 million galaxies and 1.6 million quasars, which are very bright, distant objects powered by supermassive black holes.

This is the understatement of the year (from the WaPo article):

For planning purposes, it is important to recognize that the timescale here is many billions or trillions of years. The DESI observations may be cosmically consequential but do not rise to the level of an action item for us mortals.

Gotta lol at that one!
also;
FWIW: To me, the idea of an evolving Dark Energy seems strangely palatable for some reason. The universe is obviously big enough to give rise to many temporal and physical possibilities, both conceivable and unconceivable by us humans, I think. The fact that the data doesn't allow for ruling out an evolving Dark Energy, sounds encouraging from a new theoretical Physics discovery viewpoint.

 

[Shemjaza]

This is the understatement of the year (from the WaPo article):

Gotta lol at that one!
also;
FWIW: To me, the idea of an evolving Dark Energy seems strangely palatable for some reason. The universe is obviously big enough to give rise to many temporal and physical possibilities, both conceivable and unconceivable by us humans, I think. The fact that the data doesn't allow for ruling out an evolving Dark Energy, sounds encouraging from a new theoretical Physics discovery viewpoint.

On an extreme timeline it might reduce the isolation of the component parts of the universe.

I found it a little sad that the Universe is eventually just going to be the local group as a single galaxy alone in the dark.

 

[SelfSim]

On an extreme timeline it might reduce the isolation of the component parts of the universe.

I found it a little sad that the Universe is eventually just going to be the local group as a single galaxy alone in the dark.

Meh .. we're already living an isolated existence in many ways, yet the space of what's possible keeps expanding as we move onwards in time in our own causal direction. There's plenty of new things appearing on our temporal horizon, (IMO).

 

[Shemjaza]

Meh .. we're already living an isolated existence in many ways, yet the space of what's possible keeps expanding as we move onwards in time in our own causal direction. There's plenty of new things appearing on our temporal horizon, (IMO).

True, but the whole idea that a significant majority of the universe will be lost is unsettling. (I guess we are comfortable with losing things to time, why not space as well?)

 

[SelfSim]

True, but the whole idea that a significant majority of the universe will be lost is unsettling. (I guess we are comfortable with losing things to time, why not space as well?)

I've been digging around trying to find out more about what these dudes actually concluded.

I think(?) this PhysOrg article might be about the same DESI announcement presented in the OP/WaPo article. (WaPO is evidently only randomly accessible for me, because I refuse their demands for a subscription).
As follows (from: A simulated universe works better when dark energy changes over time):

The results support the dynamic dark energy model, where dark energy changes over time. However, the authors caution that these results are not conclusive yet.

"It should be noted that because the Discovery simulations contain differences in all of their cosmological parameters, we are not isolating the effect of evolving dark energy but rather examining the differences in these two simulations based on their overall cosmologies," the authors explain in their paper.

So, we should take it all with a grain of salt, I gather.
Ie: Its about differences in model simulations as a way of trying to select a 'best' model and not necessarily about DM halos/DE in isolation of all the other cosmo parameters.

 

[The Liturgist]

The fate of the universe is still very much up in the air.

Right now it is expanding, at an accelerating rate. If nothing changes, many billions or trillions of years from now the universe would presumably become cold, dark and inhospitable.

Indeed this would be my preferred outcome, because in the unlikely event exotic matter exists and we can warp spacetime, it would be lovely to put a restaurant at the end of the universe as proposed by Doug Adams, memory eternal.

Whereas conversely if a big crunch happens, while it would make the end of the universe more definite, it would be much harder to install a safe, stable restaurant there, and that thought makes me sad.

Also it is very unlikely Poul Anderson’s proposal in Tau Zero to travel around the new Big Bang in a starship would work. Travel into the new universe would surely be impossible without being thermalized.

 

[SelfSim]

Indeed this would be my preferred outcome, because in the unlikely event exotic matter exists and we can warp spacetime, it would be lovely to put a restaurant at the end of the universe as proposed by Doug Adams, memory eternal.

Whereas conversely if a big crunch happens, while it would make the end of the universe more definite, it would be much harder to install a safe, stable restaurant there, and that thought makes me sad.

Also it is very unlikely Poul Anderson’s proposal in Tau Zero to travel around the new Big Bang in a starship would work. Travel into the new universe would surely be impossible without being thermalized.

Meh .. humans will work out a way around all those cosmic building regulations ..
Mind you .. the Vorgons!

 

[tharkun73]

Can I borrow a towel? Forgot mine....

 

[R.W. Smith]

I was born and raised to believe in evolution and an old universe that began with an idea that was invented which was called "big bang".
I started kindergarten in the fall of '63. Fast forward to, oh, the fall, perhaps, of 2023. I was listening to a talk by Father Ripperger and Hugh Owen(s?). My vision of the universe has changed.
One of Father Rippiger's points is that the natural scientists were finding any way they could to keep God out of Creation. One of the things they dreamt up to explain their observations was "dark matter" and then "dark energy". I have not studied any science for over 50 years, but I can understand the philosophical ideas supporting scientific endeavours.
I have learned to trust inerrant Divine Revelation rather than fallible scientists. I now believe in a "young earth" and a geocentric universe. It is still sometimes shocking to me, but God has told us when and where the earth was created.
Apparently, the centrifugal forces produced by the universe revolving around the earth accounts for all the problems that resulted in men conjecturing "dark matter" and "dark energy".
For more information please see Kolbe Center for the Study of Creation – A Catholic apostolate dedicated to proclaiming the truth about the origins of man & the universe

 

[The Liturgist]

Can I borrow a towel? Forgot mine....

Whatever for?

 

[The Liturgist]

One of Father Rippiger's points is that the natural scientists were finding any way they could to keep God out of Creation.

I don’t agree with that sentiment. The Roman Catholic church has produced many of the great astrophycisists of the past 150 years. Dark energy and dark matter are theoretical attempts to understand what we see in the universe, specifically the distribution of matter in galaxies (there does not appear to be enough regular matter to hold the galaxies together) and the accelerating expansion of the universe (the expansion first noticed by Edwin Hubble in the 1920s, and the expansion being discovered in the 1990s in part through observations made using the telescope named for him).

I can’t think of any way in which this scientific research poses a threat to faith in God or the existence thereof - it is rather about admiring the beauty of His creation and understanding the physical properties God has bestowed upon it.

 

[sjastro]

I was born and raised to believe in evolution and an old universe that began with an idea that was invented which was called "big bang".
I started kindergarten in the fall of '63. Fast forward to, oh, the fall, perhaps, of 2023. I was listening to a talk by Father Ripperger and Hugh Owen(s?). My vision of the universe has changed.
One of Father Rippiger's points is that the natural scientists were finding any way they could to keep God out of Creation. One of the things they dreamt up to explain their observations was "dark matter" and then "dark energy". I have not studied any science for over 50 years, but I can understand the philosophical ideas supporting scientific endeavours.
I have learned to trust inerrant Divine Revelation rather than fallible scientists. I now believe in a "young earth" and a geocentric universe. It is still sometimes shocking to me, but God has told us when and where the earth was created.
Apparently, the centrifugal forces produced by the universe revolving around the earth accounts for all the problems that resulted in men conjecturing "dark matter" and "dark energy".
For more information please see Kolbe Center for the Study of Creation – A Catholic apostolate dedicated to proclaiming the truth about the origins of man & the universe

Since you believe in a geocentric universe explain how the following observations are consistent with a stationary Earth.
(1) The observation of stellar parallax.
(2) The temperature variations associated with the l = 1 dipole for the Cosmic Microwave Background.

An example of the failure of Plasma Cosmology

If you read the hysterical response to your post at EU central you might to want change your assessment from "stubborn refusal to comprehend the paradox" to "incapable of comprehending the paradox." He literally does not understand the statement he quoted. I suppose that's what happens when...

www.christianforums.com

The list is by no means exhaustive.

 

[Hans Blaster]

Whatever for?

It was posted at the town planning office last week, demolition begins today for the new bypass.

 

[Hans Blaster]

I was born and raised to believe in evolution and an old universe that began with an idea that was invented which was called "big bang".

Evolution and the old universe are not things to be "believed". Science doesn't work on faith or belief.

I started kindergarten in the fall of '63. Fast forward to, oh, the fall, perhaps, of 2023. I was listening to a talk by Father Ripperger and Hugh Owen(s?). My vision of the universe has changed.
One of Father Rippiger's points is that the natural scientists were finding any way they could to keep God out of Creation.

Scientist don't do anything to "keep your god" out of things. There was never any god inserted in science by scientists to begin with.

One of the things they dreamt up to explain their observations was "dark matter" and then "dark energy". I have not studied any science for over 50 years,

It shows.

but I can understand the philosophical ideas supporting scientific endeavours.

Not doing so well so far.

I have learned to trust inerrant Divine Revelation rather than fallible scientists.

Science doesn't work on "revelation" or fallibility. We are well aware that we are not perfect.

I now believe in a "young earth" and a geocentric universe. It is still sometimes shocking to me, but God has told us when and where the earth was created.
Apparently, the centrifugal forces produced by the universe revolving around the earth accounts for all the problems that resulted in men conjecturing "dark matter" and "dark energy".

Neither dark matter nor dark energy have anything to do with "centrifugal forces" of the universe. The person who posited a missing "dark" mass for galaxy rotation wasn't a man.

For more information please see Kolbe Center for the Study of Creation – A Catholic apostolate dedicated to proclaiming the truth about the origins of man & the universe

So much for the last thread of credibility for my old church...

 

[awstar]

Since you believe in a geocentric universe explain how the following observations are consistent with a stationary Earth.
(1) The observation of stellar parallax.

Do you mean the observed negative stellar parallax too?

No problem!

Chapter 25: The 'Negative' Stellar Parallax demystified – Nextra

He who goes slowly goes well — and goes far (old Italian adage)

book.tychos.space

 

[Larniavc]

I have not studied any science for over 50 years,

You probably should if you want to contribute to a science sub fora.

 

[sjastro]

Do you mean the observed negative stellar parallax too?

No problem!

Chapter 25: The 'Negative' Stellar Parallax demystified – Nextra

He who goes slowly goes well — and goes far (old Italian adage)

book.tychos.space

If you had done a bit more research on the link you posted, you would have noted the comment “In the TYCHOS model, however, the Earth only moves by a mere 7018 km every six months.”, which does not support geocentricism as the Earth is supposed to be stationary.

Along with this inconvenient fact the link is riddled with errors, a negative parallax is not a real effect.
For nearby stars the parallax p is large and the uncertainty or error σₚ in the measurement is small, while for more distant stars, p becomes smaller and σₚ larger.
The Signal-Noise-Ratio SNR = p/σₚ is high for nearby stars.
For example a star with an average value p = 100 milliarcseconds and error σₚ = 0.1 milliarcseconds , the SNR = 100/0.1 = 1000 is very high whereas for distant stars where the foreground and reference background stars are fainter, average p = 0.1 milliarcseconds and error σₚ = 0.2 milliarcseconds, the SNR = 0.5 which is very low and can lead to negative p values as the error exceeds the average.

In the Gaia catalogue the 540,000 odd measured stars within 100 parsecs from Earth all have positive parallaxes, beyond 3000 parsecs the incidence of negative parallaxes increases for the reasons given. It is very convenient for the link to omit the relationship between negative parallax and distance.

The nonsense comments that the Earth moves 7018 km every six months is totally refuted by radar ranging by bouncing radar signals off planets such as Mars and Venus and spacecraft telemetry such as the Cassini mission to Saturn which used radio signals to track Earth-Saturn distances, allowing precise calculation of the AU (astronomical unit) using Kepler’s laws.
The baseline for calculating parallax turns out to being 2 AU or ~300 million km not 7018 km.

 

[awstar]

If you had done a bit more research on the link you posted, you would have noted the comment “In the TYCHOS model, however, the Earth only moves by a mere 7018 km every six months.”, which does not support geocentricism as the Earth is supposed to be stationary.

I was already aware of the motion of the Earth in Simon Shack’s The Tychos simulation. His simulation model actually started me thinking several years ago about how the geocentric model has to be equivalent to the heliocentric model. My preferred model though is the neo-Tycho model of Luka Popov.

Reference: Popov L 2013 Newtonian-Machian analysis of Neo-tychonian model of planetary motions Eur. J. Phys. 34 383 (Preprint arXiv:1301.6045v2)

sjastro​

Along with this inconvenient fact the link is riddled with errors, a negative parallax is not a real effect.
...
In the Gaia catalogue the 540,000 odd measured stars within 100 parsecs from Earth all have positive parallaxes, beyond 3000 parsecs the incidence of negative parallaxes increases for the reasons given. It is very convenient for the link to omit the relationship between negative parallax and distance.

To a Capernican fan It is required to be “not a real effect”. Otherwise their theory would be falsified!

I found the source for what both you and Simon Shack were referring to. To quote the keepers of the data (ESA European Space Agency):

Perhaps this is most easily appreciated by considering the 0.5 million QSOs appearing in Gaia DR2 for which parallax solutions have been made. Given that the true parallax for these sources is close to zero it is to be expected that for half of them the observed parallax (as solved for from the observations) is negative (where in the case of Gaia DR2 the fraction of negative parallaxes for QSOs is higher because of the negative parallax zero point).

…

Hence negative parallaxes represent perfectly valid measurements and can be included in analyses of the Gaia DR2 data.

Gaia Data Release 2 - Gaia - Cosmos

Gaia Data Release 2

www.cosmos.esa.int

D = 1/parallax has a real meaning when both positive and negative values are used. The absolute value is a real distance. It just means the left eye is used instead of the right in the popular analogy used in describing what parallax is. But you say half the data should be assumed useless because it’s negative? So it makes me wonder — how can half the data be ruled out for one reason or another, and not view the other half with suspicion? It seems to me heliocentricity is already baked into the interpretation of the data. How convenient is that when comparing of the two models?