Our Universe wasn’t empty, even before the Big Bang

Post by pixl97 » Thu, Jul 27, 2023, 8:05 PM UTC

goatlover wrote: post #39

ecf wrote: post #37

This makes sense if we don’t consider the Big Bang as the “creation” of our universe but rather just another event that happens in it. Thermodynamic laws and how our universe is expanding are both fairly well understood. Is it too much of a stretch to think that our universe has gone through many expansion and contraction cycles? It expands until heat death, then black holes take over. These black holes slowly swallo…

Problem with this is that blackholes will eventually evaporate due to radiating Hawking radiation. That and expansion is (probably) speeding. Evidence is against gravity slowing that down.

Post by [deleted] » Thu, Jul 27, 2023, 9:38 PM UTC

fasterik wrote: post #27

edgyquant wrote: post #16

Earlier quoted context omitted.

I really don’t think it’s hard and basically everyone knows what is meant by this. Physicists just like to be pedantic about the technicalities of what “before” means.

If we're talking about a singularity, it's not pedantic. If you reverse time and go back to the Big Bang, it's not possible to define what happens after you hit the singularity, at least according to current theories. As another commenter pointed out, the article is referring to the "hot Big Bang era", not the Big Bang singularity, so that's what is causing the confusion. It is possible to talk about what happened du…

Post by digging » Thu, Jul 27, 2023, 10:14 PM UTC

goatlover wrote: post #38

digging wrote: post #35

Earlier quoted context omitted.

The age of the universe seems to me to be completely irrelevant to the existence of time "prior" to the beginning of time. It's like asking what is "outside" an infinite universe.

Or a bounded but finite one with a topology that folds back in on itself. What confuses me is when physicists talk of spacetime (maybe) emerging from something more fundamental