# Evidence that Universe’s Expansion is Decelerating

**URL:** <https://boards.straightdope.com/t/evidence-that-universe-s-expansion-is-decelerating/1024755>\
**Category:** In My Humble Opinion\
**Created:** [November 11, 2025, 12:55am UTC](https://boards.straightdope.com/t/evidence-that-universe-s-expansion-is-decelerating/1024755 "2025-11-11T00:55:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Jackknifed\_Juggernaut](https://avatars.discourse-cdn.com/v4/letter/j/9de053/32.png) [@Jackknifed\_Juggernaut](https://boards.straightdope.com/u/Jackknifed_Juggernaut)\
**Post date:** [November 11, 2025, 12:55am UTC](https://boards.straightdope.com/t/evidence-that-universe-s-expansion-is-decelerating/1024755/1 "2025-11-11T00:55:46Z")

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Surprised that [this](https://ras.ac.uk/news-and-press/research-highlights/universes-expansion-now-slowing-not-speeding?utm_source=join1440&utm_medium=email&utm_placement=newsletter&user_id=67a26f52c04f458d2c0afc1d) isn’t bigger news, so not sure how seriously I should take it. Wouldn’t it upend alot of current prevailing astronomical theories?

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**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\
**Post date:** [November 11, 2025, 1:09am UTC](https://boards.straightdope.com/t/evidence-that-universe-s-expansion-is-decelerating/1024755/2 "2025-11-11T01:09:32Z")

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I think the key in that article is the phrase “if the results are confirmed”.

Here is Smithsonian Magazine’s article on it:  
[https://www.smithsonianmag.com/smart-news/the-universes-expansion-may-be-slowing-down-not-speeding-up-new-research-suggests-180987660/](https://www.smithsonianmag.com/smart-news/the-universes-expansion-may-be-slowing-down-not-speeding-up-new-research-suggests-180987660/)

The article includes this quote:

> [@](#):
>
> Some scientists not involved in the work, however, contest those conclusions. [Adam Riess](https://www.stsci.edu/~ariess/index.htm), an astrophysicist at the Space Telescope Science Institute, tells Jonathan O’Callaghan at [_New Scientist_](https://www.newscientist.com/article/2503263-is-the-expansion-of-the-universe-slowing-down/) that previous work from the research group, which made similar claims, has been refuted. “The same group’s new work repeats the argument with little change,” he says.
> 
> He explains that it’s difficult to measure stellar ages for type Ia supernovae at large distances, and that Lee’s team used an average stellar age for their study. “The theory behind this is weak because of a lack of certainty about how the [star] forms,” he adds.

My take on it is that it needs a lot more review and follow-up studies before we all start getting excited and completely up-ending our current theories about the universe.

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**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\
**Post date:** [November 11, 2025, 4:11am UTC](https://boards.straightdope.com/t/evidence-that-universe-s-expansion-is-decelerating/1024755/3 "2025-11-11T04:11:22Z")

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My prediction; the expansion continues to decelerate until it stops and then the contraction phase begins. That ends with the universe compressed back into a point. I think you can guess what happens next.