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<blockquote data-quote="freyar" data-source="post: 6683545" data-attributes="member: 40227">More on the multiverse later, but I quickly wanted to clear up a confusing bit of terminology.There are actually two slightly different meanings of &quot;Big Bang&quot; in physics, which are often not carefully disambiguated (to borrow a term from wikipedia).&nbsp; One common one, which Umbran seems to be using, might be specified as the &quot;Big Bang Singularity,&quot; meaning the beginning of space and time.&nbsp; There is literally no time before that.&nbsp; This is a singularity in general relativity but might be smoothed out in some theory of quantum gravity, like string theory.&nbsp; There is some but not a lot of research on fixing the Big Bang Singularity in string theory.&nbsp; I've done a little bit of work related to that.The second common definition, which I think fuindordm is using, is often called the &quot;Hot Big Bang.&quot;&nbsp; This is the period in the early universe (after the period of inflation fuindordm talked about) when there was a dense hot plasma of stuff.&nbsp; This is, for example, when the different isotopes of the light elements are formed (this is called Big Bang Nucleosynthesis).&nbsp; Anyway, I hear and use &quot;Big Bang&quot; both ways, and it's an understandable confusion.More of a substantial answer either tonight or tomorrow on the multiverse.</blockquote>

[QUOTE="freyar, post: 6683545, member: 40227"] More on the multiverse later, but I quickly wanted to clear up a confusing bit of terminology. There are actually two slightly different meanings of "Big Bang" in physics, which are often not carefully disambiguated (to borrow a term from wikipedia). One common one, which Umbran seems to be using, might be specified as the "Big Bang Singularity," meaning the beginning of space and time. There is literally no time before that. This is a singularity in general relativity but might be smoothed out in some theory of quantum gravity, like string theory. There is some but not a lot of research on fixing the Big Bang Singularity in string theory. I've done a little bit of work related to that. The second common definition, which I think fuindordm is using, is often called the "Hot Big Bang." This is the period in the early universe ([B]after[/B] the period of inflation fuindordm talked about) when there was a dense hot plasma of stuff. This is, for example, when the different isotopes of the light elements are formed (this is called Big Bang Nucleosynthesis). Anyway, I hear and use "Big Bang" both ways, and it's an understandable confusion. More of a substantial answer either tonight or tomorrow on the multiverse. [/QUOTE]

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