From: Jeffrey Epstein <[email protected]> To: Lisa Randall Subject: Re: Date: Fri, 02 Oct 2009 21:59:50 +0000 sorry, On Fri, Oct 2, 2009 at 5:41 PM, Lisa Randall < > wrote: I think I'm reaching the limits of my ability to disentangle grammar and spelling but here goes: Jeffrey Epstein wrote: thanks , question , what does it look like if time is running backward , wouldn't it be decelerating„ into flat space from the singularity outward„ therefore explosion than [then] expansion. It looks like big bang, not inflation before horizon. So not explosive expansion. but always slowing after crossing the horizon . after crossing horizon there isn't really a cosmological interpretation anymore. Time and space have switched back. looking in reverse it appears things accelerate as they approach„ charged would be as a result of the deceleration. don't understand this last comment. On Fri, Oct 2, 2009 at 5:27 PM, Lisa Randall < <mailto: > wrote: Hi Jeffrey. It was interesting-as always. For your question, let's first straighten out that there are 3 types of bhs we might be discussing: Schwarschild, charged, and Kerr. I didn't say much about Kerr--I mostly discussed charged-- since they are changing with time and a bit more complicated but indeed they have 2 horizons (just like charged black holes). Two horizon scenario means time and space switch twice so at singularity you are back to ordinary time space identification. So let's first just consider Schwarschild (uncharged, not rotating). In that case you are on the right track. Reversing time and coming from the singularity, it pretty much looks like a 2d big bang scenario (with the other 2d in a compact sphere). Space expands out until you reach the horizon and eventually goes over into flat space. It's not really accelerated expansion but still somewhat along lines you suggested. If there are two horizons (charged black hole case) and you are in between them (we called this Whoville