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CaptDude
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Obviously, I can understand the literal meaning of the phrase "the big bang happened everywhere at once" But I have never read a satisfactory explanation that eloquently helped me understand this concept...
Imagine a volume of space. It may be either infinite in extent, or finite in a way that curves on itself, so that going straight in anyone direction makes you come back to where you started.CaptDude said:Obviously, I can understand the literal meaning of the phrase "the big bang happened everywhere at once" But I have never read a satisfactory explanation that eloquently helped me understand this concept...
I agree w/ your post but this opening statement promotes the mistaken belief that it started at a point in SPACE, which it did not (as you clearly point out later) since if it had, there would be a center to the universe and there would consequently be a preferred direction to the motion of the expansion. There is neither.Clayjay said:Space-time mathematically starts at a point.
Clayjay said:Space-time mathematically starts at a point.
CaptDude said:"the big bang happened everywhere at once"
Helios said:It seems that all of infinite space had to do something on cue to get things started, and this contradicts my intuition as to how this is possible.
Helios said:What bugs me is how some universal happening can happen everywhere at once.
"Singularity" just means "the place where our math model breaks down and we don't know WHAT the hell was/is going on". ("was" in the case of the BB, "is" in the case of a black hole). It iS NOT a point.Helios said:Do cosmologist who believe in an original singularity believe that infinity can originate out of point? Or does a singularity necessarily imply a finite universe? Or conversely, would an infinite universe negate the singularity belief?
Helios said:Do cosmologist who believe in an original singularity believe that infinity can originate out of point?
You are getting confused because of the two radically different ways the term "big bang" is used. One way, the only way in my opinion that is meaningful or helpful, is the "Big Bang Theory" which is a very (but not completely well understood description of how the universe evolved starting at about one Planck Time after the "singularity" and saying NOTHING about anything before one Planck Time (other than "don't know WHAT was going on back then") and the other is just a reference to the singularity (more properly called the Big Bang Singularity) which is just a place where the math model breaks down and something we can't really say anything meaningful about (other than "don't know WHAT was going on back then")CaptDude said:Thanks for all the replies. Very good information. However, I need to ask another question. Am I mistaken in saying I think the phrase "the big bang happened everywhere at once" could be rephrased as "inflation happened everywhere at once." Having asked that, even I don't think that is correct because, if I remember correctly, inflation began a micro-fraction of a second AFTER the big bang.
Yet a lot of you seem to be referrencing inflation in your answers.
Am I making it harder to understand than it is? Is my "eloquent" answer simply that space time started at a "point" (I know this is not correct but I don't know how to phrase it right) and then inflation expanded space/time to "everywhere at once"?
P.S. I am very happy to have found a place to enrich my understanding of life, the universe, and everything. ;)
Helios said:Do cosmologist who believe in an original singularity believe that infinity can originate out of point? Or does a singularity necessarily imply a finite universe? Or conversely, would an infinite universe negate the singularity belief?
Helios said:For an infinite universe, I don't believe that shrinking the scale factor will every result in a point.
Helios said:How can time start everywhere at once.
Helios said:Or how could inflation begin or end everywhere at once
Can you name the centre of the surface of a sphere?CaptDude said:I also want to sk about the universe having to center. If the universe is infinite, that is understandable. But if the universe is finite, it is harder to understand. How can any finite geometric shape have no center?
The statement is to emphasise that whatever the Big Bang Singularity was, it was not a single point in space as it is always portrayed on TV pop-sci programs.CaptDude said:Am I mistaken in saying I think the phrase "the big bang happened everywhere at once" could be rephrased as "inflation happened everywhere at once."
I suggest you read the article linked to in my signature.I also want to sk about the universe having to center. If the universe is infinite, that is understandable. But if the universe is finite, it is harder to understand. How can any finite geometric shape have no center?
Bandersnatch said:Can you name the centre of the surface of a sphere?
phinds said:The statement is to emphasise that whatever the Big Bang Singularity was, it was not a single point in space as it is always portrayed on TV pop-sci programs.
I suggest you read the article linked to in my signature.
Not sure why you'd think it's only metaphorical.CaptDude said:So the statement "the big bang happened everywhere at once" is not to be taken literally but metaphorically?
It is quite appropriate to carry on when you still have questions. As Dave said, it IS literal, I was just emphasizing the aspect of its refuting the "singularity = point" point of view. We have no idea how big the early universe was. It might have been infinite or it might have been finite but unbounded (as bandersnatch pointed out).CaptDude said:y
I apologize if I am belaboring the point, but I really want to grasp the answers I am getting to my question; and since it seems this concept is one of the most misunderstood areas of cosmology, I will carry on with questions. I am getting there, but I have not arrived. Once again, I feel my following question is wrong - but I need to ask it anyway. So the statement "the big bang happened everywhere at once" is not to be taken literally but metaphorically?
I had good input from a number of people here before I got to the final version.P.S. Phinds, I did read your article before and after your previous post. Good stuff, thanks for the resource.
I ask these questions after decades of self learning by reading about quantum entanglement, the duel slit experiment, Bose–Einstein condensate, the Copenhagen Interpretation of quantum systems, Heisenberg's uncertainty principle, Schrödinger's cats and kittens, gravity waves, and anything else I could find on quantum physics and cosmology. I state this to provide a list of subject for others to explore and to show I have some level of understanding and that my questions are to help me understand what I have not been able to learn from "traditional reading sources"
phinds said:It is quite appropriate to carry on when you still have questions. As Dave said, it IS literal, I was just emphasizing the aspect of its refuting the "singularity = point" point of view. We have no idea how big the early universe was. It might have been infinite or it might have been finite but unbounded (as bandersnatch pointed out).
I had good input from a number of people here before I got to the final version.
DaveC426913 said:Not sure why you'd think it's only metaphorical.
It may be counter-intuitive, but I think it's pretty literal.
The way to intuit it might be in recognizing that... "Everywhere" was a very small place, a long time ago.
CaptDude said:(1) The big bang did not happen in space, it happened in time.
CaptDude said:If #2 is correct, then space (all places) was (were) created at that moment so that we say “the big bang happened everywhere at once”
I agree this is a better way to express it. Thanks for that improvement on my statement.PeterDonis said:The only potential issue with this way of putting it is that the word "created" isn't really the right word, because it implies that spacetime was created from something else. A better way of putting it would be to say that the Big Bang is a boundary of spacetime; and since all spatial locations in spacetime are "next to" the boundary at the instant right after it, the Big Bang happened everywhere at once.
PeterDonis said:Your follow-up question here shows that you are uncomfortable with this idea, which you should be. You are right that space and time go together.
This is correct as far as it goes; but you have left out one thing, which phinds mentioned: the Big Bang created time as well as space, because it created spacetime.
The only potential issue with this way of putting it is that the word "created" isn't really the right word, because it implies that spacetime was created from something else. A better way of putting it would be to say that the Big Bang is a boundary of spacetime; and since all spatial locations in spacetime are "next to" the boundary at the instant right after it, the Big Bang happened everywhere at once.