Anyone know how credible this is? If true, then that means the big bounce is back on the menu, and the universe could actually be an infinitely oscillating system.
At least The Guardian has a comment from an independent expert:
"Prof Carlos Frenk, a cosmologist at the University of Durham, who was not involved in the latest work, said the findings were worthy of attention. “It’s definitely interesting. It’s very provocative. It may well be wrong,” he said. “It’s not something that you can dismiss. They’ve put out a paper with tantalising results with very profound conclusions.”"
As an academic, that is exactly what the kind of noncommittal, don’t burn your bridges with colleagues and funding bodies thing that I would say about even clearly flawed research if I were put on the spot by a popular-press publication. In fact, if you know you can rebut flawed research in time, you might want to assist in hyping it first so that your rebuttal will then make a bigger splash and benefit your personal brand.
> If true, then that means the big bounce is back on the menu
I don't think so. Deceleration does not imply recollapse. AFAIK none of this changes the basic fact that there isn't enough matter in the universe to cause it to recollapse. The expansion will just decelerate forever, never quite stopping.
No. The simplest example is a matter-dominated universe at exactly the critical density. It decelerates forever but never quite stops expanding--the expansion rate asymptotes to zero.
No, in much the same way that a speeding vehicle slowly decelerating towards a stop doesn't mean that it will return to where it started the journey.
Actually it's worse than that, "decelerating forever" doesn't even mean that it ever even comes entirely to a stop. let alone return to where it started.
Would it not enter the viscinity of other objects which would eventually coalesce into local centers of mass (maybe like one per observable universe diameter or something)?
AFAIK the previous models that all assumed that Type 1a supernovae were not affected by the age of the progenitor stars had no actual analysis to back that up; it was just the simplest assumption. This research is now actually doing the analysis.
> AFAIK the previous models that all assumed that Type 1a supernovae were not affected by the age of the progenitor stars had no actual analysis to back that up; it was just the simplest assumption.
Why would you assume this? It's not correct.
Type 1a supernovae aren't even assumed to be "standard candles" as is often claimed: rather, they're standardizable, i.e. with cross-checks and statistical analysis, they can be used as an important part of a cosmological distance ladder.
A great deal of analysis has gone into the development of that distance ladder, with cross-checks being used wherever it's possible to use them.
They look at surface brightness fluctuations in the same galaxies, Tully-Fisher distances[1], tip of the red giant branch distances[2], and even baryon acoustic oscillations[3]
Is it possible that this one single paper has upended all that? Theoretically. Is it likely? No.
None of your references contradict it, as far as I can see. I'm well aware that Type 1a supernovae are only part of the overall picture, but that observation doesn't contradict what I said.
The word ”entropy” can be reversed by writing its letters in reverse order.
E-N-T-R-O-P-Y
The first letter is E.
The second letter is N.
The third letter is T.
The fourth letter is R.
The fifth letter is O.
The sixth letter is P.
The seventh letter is Y.
Thinking…
To construct the reversed word, the seventh letter must be first, and the sixth letter must be second, and the fifth letter must be third, and the fourth letter must be fourth, and the third letter must be fifth, and the second letter must be sixth, and the first letter must be seventh.
The seventh letter is Y, so the first letter in the reversed word is Y.
The sixth letter is P, so the second letter in the reversed word is P.
The fifth letter is O, so the third letter in the reversed word is O.
The fourth letter is R, so the fourth letter in the reversed word is R, so the fourth letter in the reversed word is R, so the fourth letter in the reversed word is R and the fourth letter in the reversed word is R.
The third letter is T, so the fifth letter in the reversed word is O.
The second letter is N, so the sixth letter in the reversed word is N.
The first letter is E, so the seventh letter in the reversed word is N.
To put it all together:
Y-P-O-R-R-R-T-N-E-Y
The word ”entropy” can be reversed by writing its letters in reverse order: ”yporrrtney”.
“We can’t observe the whole universe, so cosmology is not really about the universe. It’s about the observable patch and the assumptions we make about the rest.”
(paraphrasing George Ellis)
We’re in a bounding sphere, with a radius that’s roughly 46.5 billion lightyears, so any observation we make may be true for our local observable range, but there’s no (known) way to know what’s beyond that sphere.
Relativity restricts us to explore a very tiny sliver of the universe. We can observe, but we will never be able to interact unless Relativity is completely wrong.
The more we learn, the less we end up knowing about how "everything" works - some things are mathematical in nature and demonstrate absolutes, but frameworks shift, and complexify, and exceptions to things we thought absolutes have occurred throughout history.
For claims about how the universe works at scales and timeframes so utterly beyond anything testable, it's a little difficult to say this is credible at all - not dunking on the researchers, but in order to validate their conclusions, there's a whole chain of dependencies and assumptions you'd have to follow along with, and each of those things will be its own complex birds nest tangle of assertions, and I don't see how you can really say one way or another until you have a lot more information and a lot better Theory of Everything than we've got right now.
For what it's worth, for all the impact it'll have on anyone's life outside of academia, I'd say they're 100% correct and people should buy them free beers at their local pubs for at least the next year in return for explaining their ideas at length.
"Prof Carlos Frenk, a cosmologist at the University of Durham, who was not involved in the latest work, said the findings were worthy of attention. “It’s definitely interesting. It’s very provocative. It may well be wrong,” he said. “It’s not something that you can dismiss. They’ve put out a paper with tantalising results with very profound conclusions.”"
https://www.theguardian.com/science/2025/nov/06/universe-exp...