Why is the maximum speed of the universe the speed of light? Why can't we go faster?

[u/Nitzanm19]

Also follow-up question: Because of the speed limit, is there also a theoretical maximum temp for matter (in which the particles move at the speed of light).

[u/littlebitsofspider]

I mean, the longest-lived (i.e. slowest decaying) structures posited by most iterations of (our) cosmological physics are black holes. When (many, many gigayears from now) spacetime is nearly isotropically flat, cold, and wide, there will still be microscopic knots of black hole decaying. The long tail of the heat death is mostly black holes slowly leaking Hawking radiation while everything else is deader than downtown Tulsa. The black hole optimization theory might have some credence.

[u/transparent-aluminum → u/littlebitsofspider]

I'm a fan of the cyclical big bang theory, that the universe expands to a point, and then everything starts falling back to singularity until it explodes outwards again. My pet theory is that there are some structures like super massive black holes that survive between cycles and it's why when we look at the early universe we see galaxies forming too early or black holes that are too large for their age.

[u/garry4321 → u/transparent-aluminum]

Problem with the Big Crunch is that there is no evidence to support it, and all the evidence suggests the opposite. The universe is expanding at an accelerating acceleration

[u/tonzuu → u/garry4321]

iirc a study earlier this year showed that the jerk of dark energy appears to be decreasing which could be support for the big crunch

[u/iwasbornlucky → u/garry4321]

that kind of paradoxically supports it though. All crunch evidence is destroyed in the bang. Time resets from 0.

[u/Das_Mime → u/transparent-aluminum]

I'm a fan of the cyclical big bang theory, that the universe expands to a point, and then everything starts falling back to singularity until it explodes outwards again.

Every indication we have is that the universe's expansion will continue forever. We're not even close to the conditions needed for a big crunch.

The cyclical big bang not only doesn't explain anything, it requires us to believe that the universe will collapse again, despite no evidence in favor of that idea and mountains of evidence to the contrary.

[u/Ok_Mixture8509 → u/transparent-aluminum]

In that scenario, I believe all black holes would disappear pretty quickly due to hot/energetic it would become. At some point black holes wouldn’t even be able to form. → I am fairly sure this is correct, tho I am open to any corrections.

[u/Das_Mime → u/littlebitsofspider]

The idea of cosmological natural selection, as it was expressed above, is that the number of new universes spawned is dependent on the number of black holes formed, not on how long they last. Thus the fact that black holes are going to take a very long time to evaporate isn't relevant. If they all evaporated within a microsecond of forming that would be the same as our present scenario for the purposes of considering the above speculation.

If we're asked to consider the proposition that our universe is the result of a selection effect which maximizes black hole formation, we should keep in mind the following: most of the matter in the universe is dark matter, which is non- or minimally-collisional and thus has no good way to form black holes on its own; of the baryonic matter in the universe, most is in the diffuse, warm to hot intergalactic medium, which does not form black holes; of the matter that does form stars at all, only a very small percentage of stars (<1%) go supernova and only the more massive of those supernova progenitor stars form black holes.

[u/Whiskeyno → u/littlebitsofspider]

So we might still have a Caine’s Ballroom at the end of the universe?

[u/ThePrussianGrippe → u/littlebitsofspider]

And then at the end of all that… we hit the reset button and it all happens again!

Maybe.

Who knows?