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My apologies if this is a duplicate question. I could not find it. Why do we think space-time itself started at the BB? Or to word it another way, could space-time have always existed infinitely in time but only matter have 'started' in the BB?

Brad S
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    Come on, downvoting without explaining why? The OP has tried to find an answer, and the question is perfectly valid (even if we don't know the answer). – pela Mar 23 '17 at 17:57
  • +1 for making the distinction. But the problem is that the answers, or at least our best shot at the answers, will have to be in the same language as the related questions. I would suggest that you read through the answers on the right hand side of this page, and then include a link to page with an answer nearest to the one that matches your understanding. Some answers are easier to follow than others., to say the least.... –  Mar 23 '17 at 18:08
  • It's science, we don't know, we have theories. Cosmological redshift is key evidence for BB theory. Your question has a philosophical point on what time means. If there is no matter or energy can time have any meaning? For many physical theories the answer is no, there has to be change, aka interaction for their to be time. – JMLCarter Mar 23 '17 at 18:49
  • Possible duplicates: http://physics.stackexchange.com/q/24017/2451 , http://physics.stackexchange.com/q/9419/2451 http://physics.stackexchange.com/q/1915/2451 and links therein. – Qmechanic Mar 23 '17 at 18:51
  • I think my first question should have said; "Why do we think space-time... " I've made this edit/change. To which it sounds like, since we know space-time itself is expanding, when we run that backward we get ALL of matter AND ALL of space-time back to a "single point." Whatever that means in space-time context. It's crazy to try to think about. This also makes the answer to the second question "NO." Space-time didn't just exist as a giant void and then matter 'exploded' out into it. Space-time and matter expanded out together. "It's science, we don't know, we have theories." - Well said. – Brad S Mar 24 '17 at 18:52

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I never thought the big bang started time, and as far as I know no one has stated that it did start then.

The inability to detect anything from before the big bang does not mean nothing existed. My personal theory (without a theoretical physics degree) is that what we see is not the first big bang, but instead one of an infinite amount of them in an infinite universe. Given infinite space and infinite time, there are other big bangs happening right now just so far out of our observational range we cannot and may never detect them. Matter is continuously converted to and from energy in an infinite loop. This is the nature of infinity right?

Drew K

Gwydionforge
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