*'''Joseph Silk:''' ''Maybe long before inflation there was a Universe that was collapsing near a [[singularity]], which then inflated again, so there was already a history before the [[Big Bang]]. Some people think there was a 'pre-Big Bang'. One possibility is that this pre-Big Bang, if there was such a place, would have made lots of entropy (the amount of disorder in the Universe). And the Universe we live in does have huge amounts of entropy. That's one theory. But we have no understanding of how to change from collapsing to expanding. There's no physical way to explain that transition. Some people believe that they have explanations the pre-Big Bang, so it's a respectable theory.''</blockquote> | *'''Joseph Silk:''' ''Maybe long before inflation there was a Universe that was collapsing near a [[singularity]], which then inflated again, so there was already a history before the [[Big Bang]]. Some people think there was a 'pre-Big Bang'. One possibility is that this pre-Big Bang, if there was such a place, would have made lots of entropy (the amount of disorder in the Universe). And the Universe we live in does have huge amounts of entropy. That's one theory. But we have no understanding of how to change from collapsing to expanding. There's no physical way to explain that transition. Some people believe that they have explanations the pre-Big Bang, so it's a respectable theory.''</blockquote> |