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.
time to re-read "The Last Question"
Analysis indicates that the universe’s expansion is not accelerating
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Re: Analysis indicates that the universe’s expansion is not accelerating
#32> type Ia supernovae, long regarded as the universe’s "standard candles", are in fact strongly affected by the age of their progenitor stars.
A key point in the article. From what I understand, this is the main way we measure things of vast distance and, from that, determine the universe's rate of expansion. If our understanding of these supernovae is wrong, as this paper claims, that would be a massive scientific breakthrough.
I'm really interested in the counterargument to this.
Re: Analysis indicates that the universe’s expansion is not accelerating
#33Circular universe...?
big bang -> expands -> expansion slows -> starts retracting -> singularity again -> big bang again
Roger Penrose seems to be leaning/more convinced of the circular universe theory....
Re: Analysis indicates that the universe’s expansion is not accelerating
#34Was there a date at the top of this? I didn't see one. I saw a similar headlines earlier this year and I'm trying to understand that this is something new
>>>Submitted by Sam Tonkin on Thu, 06/11/2025 At the very bottom. Weird how style guides keep putting important information like this in harder to reach places.
Is it SEO? IIRC there's a trend of removing dates from blog posts and articles, and my understanding it's to make the content seem more "evergreen" to Google (vs and article with a date, they may get down-ranked eventually due to age).
Re: Analysis indicates that the universe’s expansion is not accelerating
#35Re: Analysis indicates that the universe’s expansion is not accelerating
#36Re: Analysis indicates that the universe’s expansion is not accelerating
#37Anyone 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.
> 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.
Re: Analysis indicates that the universe’s expansion is not accelerating
#38Earlier quoted context omitted.
Edit: A big brain fart, ignore the retracted part below. Colonizing the universe is of course impossible in 100My, barring FTL. What the paper I referred to [1] says is that colonizing the Milky Way may take less than that, and if you can do that, spreading to the rest of the observable universe is fairly easy, very relatively speaking. According to some calculations, it should in principle be possible to colonize th…
> According to some calculations, it should in principle be possible to colonize the entire observable universe in less than a hundred million years ...what? That doesn't seem right, just from a really quick gut check it looks like the observable universe has a radius of 45.7 billion light years [0]. Even if the universe wasn't expanding nobody could get to everything any faster than that number of years right? Maybe…
>> According to some calculations, it should in principle be possible to colonize the entire observable universe in less than a hundred million years
> ...what? That doesn't seem right, just from a really quick gut check it looks like the observable universe has a radius of 45.7 billion light years [0].
I guess it depends on whose hundred million years you're talking about: the colonists' or those who stay home's. I don't know how to do the calculations, but it seems plausible that you could traverse the entire observable universe at near light-speed in 100 million years ship time.
Re: Analysis indicates that the universe’s expansion is not accelerating
#39Aside from unanswerable questions (has the universe started to fill it's container? Is a simulation property nearing "1"?), does this make long distance space travel feasible again? I thought there was something around the universe is expanding too fast to visit places like Alpha Centuri (and preventing visitors to us).
The limit to space travel is the Rocket Equation, which says that you require exponential fuel to reach higher speeds. Alpha Centauri isn't going anywhere, but it will take millennia of travel even with wildly optimistic assumptions.
Also note that there isn't any "container" to fill up. It could well be infinite. It's just that we will be forever limited to a finite subset, even in theory.
Re: Analysis indicates that the universe’s expansion is not accelerating
#40I would not be surprised if the universe was somewhat elastic, expands and then contracts and then expands ad infinitam. After all, existence in itself is irrefutable and cannot not exist by definition. If we subscribe to a theory of the multiverse, set theory, likelihood, and interaction driven evolution based on gradient type of fundamental laws. Locally changing. Obviously everything sharing a fundamental quality…
> After all, existence in itself is irrefutable and cannot not exist by definition.
I can say the same about forgnoz, which is something I've just invented that must exist by definition.
You'd need to try a bit harder to make existence actually inevitable.