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

bigthink.com

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

#31

Post by handsaway »

yukIttEft wrote: post #21

Reading about Big Bang, I'm wondering about this: doesn't the fact that the Big Bang happened imply that there was some kind of state-change: from Big Bang is not happening to Big Bang is happening, and any kind of state-change requires the existence of time. Doesn't this imply that time existed before the Big Bang?

Assuming you mean "Big Bang" in the sense of the beginning of the universe, not necessarily.

>doesn't the fact that the Big Bang happened imply that there was some kind of state-change: from Big Bang is not happening to Big Bang is happening

Language is incredibly bad at describing this because we did not develop it when such a concept as "outside of time" existed. The word "happened" is misleading you I think. If we define "something that happened" as an event with a before and after then the Big Bang did not, by that definition, "happen".

I've had it explained to me that asking "What happened before the big bang?" is akin to asking "What's north of the north pole?"

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

#32

Post by amflare »

What is this article championing? An infinite universe? I thought that was already discarded, it certainly should be since it isn't logical. But aside from that, doesn't the theory put forward by this article violate the Second Law of Thermodynamics? It's just shifting the "nothing->something" equation from The Big Bang to "oh you know, whenever. a little bit now and again adds up you know". And seems to be doing it by saying that "Well see, the universe will never truly be empty, so before the Big Bang is wasn't empty either". Without ever really explaining how this isn't just kicking the can backwards down the road.

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

#33

Post by turndown »

AuthorizedCust wrote: post #28
rm999 wrote: post #14

There's a lot of confusion in this thread about "before the big bang". I was also confused and did some googling and found this explanation from a professor of theoretical physics. It seems that it's actually pretty normal to refer to the big bang as happening after the initial inflationary epoch, but others refer to it as the moment before this. >Do not allow yourself to be confused: The Hot Big Bang almost certainl…

Wouldn’t this be the result of some theoretical physicists moving the goalposts? It sounds like they feel the commonly accepted understanding of the Big Bang is overbroad. Fine. Find new words to describe the subsets of the event. Redefining the word is just causing confusion.

Most of the stuff I have read on this presupposes that some kind of phase transition(think of the early universe being in a 'boiling' phase and then condensating) occurred that caused the field which drove inflation(with the force carrier called the inflaton) to decay and release all the energy in the field(that is, the inflatons decayed). This decay process is what we conceive of as 'the big bang', as in the start of the energy dense Universe we see a glimpse of in the CMB.

You are right that the goalposts have been moved. When analysis of the CMB began, it was noticed that it was far too uniform in distribution and temperature for what was previously thought to be possible. It was at this point that an inflationary period was tacked on before 'the big bang' because that was the only way to get the kind of 'big bang' we seem to have had.

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

#34

Post by digging »

MattPalmer1086 wrote: post #19
digging wrote: post #9

This article doesn't make any sense. Skimming over it, I don't see that it's even about "before the Big Bang," which is a nonsense phrase. Nor do I see why it's arguing the point that our universe has even been empty, because nobody has ever argued that it was. Ah, it's talking about the future, when it might be "empty", and explaining to the reader how it won't actually be empty. That's weird. Ah, it's now circling…

The big bang has two meanings in common usage. Some people think it means "the beginning of time". But it can also refer to the time immediately after inflation. [1] [1] https://profmattstrassler.com/articles-and-posts/relativity-...

Whoops. I've never heard of the "Hot Big Bang" as a period that began after inflation. Thanks.

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

#35

Post by digging »

travisgriggs wrote: post #15

Lots of complaints here about how "before" somehow "crosses a line" and this isn't science any more. I guess I think it's more gradient than that. We're mad because this is "before", but just the other day, we had headlines indicating that ... may be ... the universe is 2x older than what I've been told for years. At this point, I'm totally with Nate Bargatze on this stuff: https://youtu.be/lkCvP4jttHI

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.

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

#36

Post by RcouF1uZ4gsC »

philsquared_ wrote: post #30
RcouF1uZ4gsC wrote: post #23

Earlier quoted context omitted.

One can do experiments to empirically test the earth is round. There are no experiments one can do to empirically test things asserted before the Big Bang.

"Dont hypothesize over anything that cannot be immediatly tested otherwise it isnt science" -rcouf1z4gsc

Yeah testable hypothesis are what separate science from other disciplines. If you don’t have a testable hypothesis, you don’t have science

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

#37

Post by ecf »

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 swallow all matter and then finally merge with other black holes. Over an unthinkable amount of time I’d imagine all those black holes become one, bringing about the concentration of mass necessary for another big bang.

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

#38

Post by goatlover »

digging wrote: post #35
travisgriggs wrote: post #15

Lots of complaints here about how "before" somehow "crosses a line" and this isn't science any more. I guess I think it's more gradient than that. We're mad because this is "before", but just the other day, we had headlines indicating that ... may be ... the universe is 2x older than what I've been told for years. At this point, I'm totally with Nate Bargatze on this stuff: https://youtu.be/lkCvP4jttHI

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

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

#39

Post by goatlover »

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.

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

#40

Post by pixl97 »

yukIttEft wrote: post #21

Reading about Big Bang, I'm wondering about this: doesn't the fact that the Big Bang happened imply that there was some kind of state-change: from Big Bang is not happening to Big Bang is happening, and any kind of state-change requires the existence of time. Doesn't this imply that time existed before the Big Bang?

Short answer, no what we at least think of time and the other fundamental rules of physics didn't have to exist, or may have been different values from our universe now.

https://en.m.wikipedia.org/wiki/False_vacuum_decay

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