# Was the universe infinitely large immediately after the Big Bang? **URL:** \ **Category:** Factual Questions\ **Created:** [October 19, 2024, 9:43pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983 "2024-10-19T21:43:49Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Zakalwe](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zakalwe/32/270_2.png) [@Zakalwe](https://boards.straightdope.com/u/Zakalwe)\ **Post date:** [October 21, 2024, 1:21am UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/21 "2024-10-21T01:21:20Z")
This is where my layman head asplodes. There was energy right? Energy doesn’t, as far as I know, just exist. There was SOMETHING there to hold that energy. It could have been subatomic, it could have been quantum thingies (now I’m just Star Trekking my way through this), but there was SOMETHING that turned into particles as we know them. Could one of those somethings have travelled the length and breadth of the universe in finite time? If not, it might be more correct to say that “since expansion ended, there was no instant…”. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 21, 2024, 1:58am UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/22 "2024-10-21T01:58:48Z")
> [@Whack-a-Mole](#): > > It is a weird concept to wrap your head around but if you really want to bake your noodle consider the alternative…infinite time (no beginning and no end). Honestly I can deal with the idea of infinite time more easily than the idea of time being bounded. Our experience with time is such that if you talk about a time infinitely in the past, I can still imagine a point in time, just like the one that just passed me by as I wrote that. But when you talk about bounded time, you get into this paradoxical thinking about “What happened before there was time?” which doesn’t even make sense to ask and doesn’t relate in any way to how we experience time and space. I mean, how many times have you heard people ask, “What happened before the Big Bang?” and then physicists slap their foreheads. ---
**Author:** ![AHunter3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ahunter3/32/368_2.png) [@AHunter3](https://boards.straightdope.com/u/AHunter3)\ **Post date:** [October 21, 2024, 4:43am UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/23 "2024-10-21T04:43:36Z")
> [@Chronos](#): > > “The Big Bang” can refer to the singular moment t=0 (“Inflation ended 10^-32 seconds after the Big Bang”), or it can refer to a very early period in the Universe’s history with a vaguely-defined ending point (“Hydrogen, deuterium, and helium-3 atoms were formed during the Big Bang”), or it can refer to the entire, ongoing, expansion of the Universe, which is still continuing. In the first two senses, it’s certainly possible to talk about “after the Big Bang”. I think this says what I was attempting to say, a lot more clearly than I said it. I should not have been absolute about it, imposing the third sense as if it should be the default. But I wanted to point out that there isn’t a single shared understanding of when it ended. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [October 21, 2024, 5:21am UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/24 "2024-10-21T05:21:28Z")
> [@Francis\_Vaughan](#): > > The entire jump from ab-initio to the end of inflation took an unimaginably tiny amount of time. 10^{-32}s10−32s10^{-32}s. Yes, but the entire universe would have been point-like. The constituent that defines the universe is spacetime. When all of spacetime is compressed into a point-like entity, how does it behave? What are the effects of general relativity in terms of the initial state of the universe? Is that unimaginably brief interval comparable to the way we understand the passage of time in current terms? ---
**Author:** ![Francis\_Vaughan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/francis_vaughan/32/3093_2.png) [@Francis\_Vaughan](https://boards.straightdope.com/u/Francis_Vaughan)\ **Post date:** [October 21, 2024, 6:29am UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/25 "2024-10-21T06:29:44Z")
> [@eschereal](#): > > Is that unimaginably brief interval comparable to the way we understand the passage of time in current terms? Indeed. IMHO probably not. But that is worth what you paid for it. ---
**Author:** ![AHunter3](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ahunter3/32/368_2.png) [@AHunter3](https://boards.straightdope.com/u/AHunter3)\ **Post date:** [October 21, 2024, 7:20am UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/26 "2024-10-21T07:20:22Z")
One of the things i got from reading Hawking’s book was the image of Time plotted on a four dimensional map. A rational plane and an irrational plane, or that was the original model. Either way, he conjured up for me the sense that gravity in the dense world of the early Big Bang displaced Time so that on the original axis, Time was short, everything happened in an extremely brief time. But the occurrence of time was distorted, the way light is distorted by gravity, where the elapsed time along the imaginary dimension shifts from irrelevant to infinite. ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [October 21, 2024, 7:28am UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/27 "2024-10-21T07:28:23Z")
> [@Chronos](#): > > One question that philosophers were bandying about was “What did God do in all of the infinite time before creating the world?”, and Augustine’s answer was “There wasn’t any time before creating the world, because time is part of the world and was itself created by God”. Martin Luther, according to an anecdote, once gave the following answer when a theology student asked him the same question: “He was thinking up potential punishments for students who ask stupid questions of this sort.” Which I’ve always thought was a very lame way to get out of a perfectly legitimate question that he just didn’t have a satisfactory answer to. ---
**Author:** ![Saffer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saffer/32/6440_2.png) [@Saffer](https://boards.straightdope.com/u/Saffer)\ **Post date:** [October 21, 2024, 4:54pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/28 "2024-10-21T16:54:55Z")
Related to this question, I have often wondered: what is the minimum size the universe could be, if we assumed it is closed like a hyper torus (so that travelling far enough in a straight line brings you back to where you started), such that we could not differentiate it from an infinite and open universe ? For example, if we look far enough into the distance/past, could we tell if a past version of our current “location” was in view? If the universe was a few meters across this would be trivially easy. If the universe was larger than the distance light can travel since the Big Bang then we would not be able to tell. But is there a distance less than that where we could not tell the difference? What is the smallest such distance? ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [October 21, 2024, 5:08pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/29 "2024-10-21T17:08:42Z")
ChatGPT agrees with my recollection of a few hundred times the size of the observable universe: “Cosmologists estimate that if the universe is indeed closed, its minimum size would need to be at least around 250-500 times the diameter of the observable universe. The observable universe is about 93 billion light-years across, so a closed universe would need a diameter of at least roughly 23 to 47 trillion light-years to explain why it appears almost flat.” ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [October 21, 2024, 5:29pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/30 "2024-10-21T17:29:14Z")
I was musing on the time contraction effect of the expanding universe. To an observer in the initial picoseconds of existence, time would have been so dilated that what we perceive as a ridiculously short interval would have been like eons to the observer within the initial frame of reference, and the rate of expansion would have looked much flatter than the traditional chalice diagram. We can observe evidence of expansion. To me, this suggests that expansion must be happening at a rate that is different from the natural elasticity of spacetime. Either that or the very nature of spacetime is being distorted by the expansion. Which raises the question: does the universe have a net frame of reference? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 21, 2024, 10:28pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/31 "2024-10-21T22:28:45Z")
> [@Mijin](#): > > ChatGPT agrees with my recollection of a few hundred times the size of the observable universe: > > “Cosmologists estimate that if the universe is indeed closed, its minimum size would need to be at least around 250-500 times the diameter of the observable universe. The observable universe is about 93 billion light-years across, so a closed universe would need a diameter of at least roughly 23 to 47 trillion light-years to explain why it appears almost flat.” That’s if it’s closed via curvature. If it’s flat but closed topologically, like the hyper-torus @Saffer mentions (IIRC, there are about a dozen different topologies possible for a flat space, plus more for slightly-curved space), then it could have a diameter just a little bit greater than the distance to the cosmic microwave background radiation. > [@eschereal](#): > > Which raises the question: does the universe have a net frame of reference? At any given point in the Universe, there’s a frame of reference that’s most convenient or “natural” for that point. But it’s a different frame of reference for every point, so there’s not one single universal natural frame. ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [October 22, 2024, 2:34pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/32 "2024-10-22T14:34:18Z")
> [@Mijin](#): > > ChatGPT agrees with my recollection of a few hundred times the size of the observable universe: ChatGPT disagrees with my claim that there are three r’s in “strawberry.” ---
**Author:** ![Jack\_Batty](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jack_batty/32/3201_2.png) [@Jack\_Batty](https://boards.straightdope.com/u/Jack_Batty)\ **Post date:** [October 22, 2024, 2:39pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/33 "2024-10-22T14:39:54Z")
Those are quantum r’s. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [October 22, 2024, 2:47pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/34 "2024-10-22T14:47:39Z")
Lol, it’s true. > [@](#): > > **Me** : Are there 3 R’s in strawberry? > > **ChatGPT** : No, there are **two** R’s in the word “strawberry.” The R’s appear in the following positions: > > - The first R is after the “t” in “straw.” > - The second R is after the “e” in “berry.” > > **Me** : Are you sure about that? > > **ChatGPT** : Oops! You’re absolutely right to question that. There are indeed **three** R’s in “strawberry”: > > 1. The first R is after the “t” in “straw.” > 2. The second R is after the “w” in “straw.” > 3. The third R is after the “e” in “berry.” > > Thank you for catching that mistake! 🤦‍♂️ ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [October 22, 2024, 11:28pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/35 "2024-10-22T23:28:58Z")
> [@Jack\_Batty](#): > > Those are quantum r’s. Are you guys just sticking “quantum” in front of everything? ---
**Author:** ![CoolHandCox](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/coolhandcox/32/16233_2.png) [@CoolHandCox](https://boards.straightdope.com/u/CoolHandCox)\ **Post date:** [October 23, 2024, 2:31pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/36 "2024-10-23T14:31:12Z")
Yes and no ---
**Author:** ![hibernicus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/hibernicus/32/2802_2.png) [@hibernicus](https://boards.straightdope.com/u/hibernicus)\ **Post date:** [October 23, 2024, 8:25pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/37 "2024-10-23T20:25:57Z")
I have a follow-up question. It is absolutely clear to me that it’s not possible for the universe to have transitioned from being of finite extent to being of infinite extent. Chronos confirmed this in an early post. But I am having difficulty articulating why I know this to be the case. Can anyone help me to state logically why this is the case? Or if you disagree, explain why it’s not necessarily the case? ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [October 23, 2024, 9:24pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/38 "2024-10-23T21:24:42Z")
There are some classical results: > > There are some classic results showing, on Lorentzian spacetime, topology changes violate causality (Geroch proved this in the '60s) or cannot satisfy the Einstein equations with non-negative energy density (Tippler proved this in the '70s). On the other hand, in some regime quantum gravity should apply, and all the “logic” needs to be reconsidered in that context. ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [October 23, 2024, 10:03pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/39 "2024-10-23T22:03:58Z")
> [@hibernicus](#): > > It is absolutely clear to me that it’s not possible for the universe to have transitioned from being of finite extent to being of infinite extent. As with all things relativistic, one must take care with specifying the observer. A finite inflationary bubble can indeed produce an infinite open universe as far as observers inside claim. Inflation models that do this are a little more complicated than others, typically proceeding in at least two steps, but they do exist and are studied a bit (but not a ton since there is no evidence that we need them). ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [October 23, 2024, 10:33pm UTC](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983/40 "2024-10-23T22:33:24Z")
To add: As a starting point, you could make sure you can convince yourself of (or ask about) “less” abstract geometrical oddities. For instance (and not related in any direct way to inflation models), consider (1) [Gabriel’s horn](https://en.wikipedia.org/wiki/Gabriel%27s_horn) with infinite area but finite volume, (2) an observer noting that a black hole’s event horizon is a finite distance away but takes an infinite time for something to reach, or (3) an observer moving past said event horizon suddenly finding that the entirety of the rest of the universe outside the horizon is no longer located on any part of any path they choose to travel in. [Previous page](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983.md?page=1) [Next page](https://boards.straightdope.com/t/was-the-universe-infinitely-large-immediately-after-the-big-bang/1008983.md?page=3)