I accept the Big Bang theory. What I can't understand is how there can be a where or when to the Big Bang if space time did not exist prior to it. Did space and time exist prior to the Big Bang?

  • $\begingroup$ Review your question considering this: does it make sense to talk about things 'before' the existence of time? Of course that doesn't mean the Big Bang theory is complete and there isn't anything wrong with it/strange about it, but I'm really far too tired to be writing up any sort of useful answer... $\endgroup$ – Wouter Apr 23 '13 at 1:37
  • $\begingroup$ Actually, I think your answer was very good. It was very well put. Thank you. $\endgroup$ – Argo Apr 23 '13 at 2:05
  • $\begingroup$ Search this site for "flrw metric" for lots of related answers $\endgroup$ – John Rennie Apr 23 '13 at 5:45

All of our known physical laws including GR (which have so far assumed spacetime to be smooth and quite flat) breakdown at singularities due to the infinite curvature of spacetime. Hence, we say, "One second after the big bang..., An hour after the big bang..., etc." Because, we simply don't know what happened at the instant of big bang. If there were events before the big bang, we cannot use those events to determine what happened in its future, because our laws don't work at singularities.

As far as we know, there haven't been a single consequence of the events before the big bang. So, it doesn't make any sense to talk about those events. Since they're of no use, we should probably throw them out of our model of universe and declare that time should've been created since the big bang.

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    $\begingroup$ Nice. Just to add another phrasing of the same idea, we have no way of knowing. $\endgroup$ – DilithiumMatrix Apr 23 '13 at 1:49
  • $\begingroup$ I'm just glad you guys didn't laugh at me. LOL I admit I sometimes don't really know where the line is between a philosophical question and a scientific one. :-) $\endgroup$ – Argo Apr 23 '13 at 2:11
  • $\begingroup$ Understanding that really I'm not interested in a philosophical answer... Which is why responses like "does it make sense to talk about things before time" are really very helpful; they help me learn where and how to draw that distinction between physics and metaphysics. $\endgroup$ – Argo Apr 23 '13 at 2:13

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