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 Be the first pioneers to continue the Astronomy Discussions at our new Astronomy meeting place...The Space and Astronomy Agora Re: About The Book... Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response ToPosted by Richard Ruquist on January 30, 2001 01:31:56 UTC

I would say that Greene's book and Kip Thorn's book are on the same level. Kip's book is a little more detailed and Greene's book requires a little more imagination.

The supersymmetry business below the planck level is a solution that Greene developed himself when he was a post-doc at Harvard. He presented the solution at a Northeastern University conference in like 1988.

The solution is an approximation. Well actually it is an exact solution to an approximate geometry. If the universe were two dimensional, it would be accurate. He solved the problem of a circular closed string on a 2-D plane. The solution he found was that every point a distance r from the center of a circle of radius equal to the planck length, was exactly mapped into a point 1/r within the circle. So all the features of the 2-D world outside the circle were reflected on a smaller scale inside the circle.

So if in the Big Crunch, the world outside the circle is collapsing on it, then the world within the circle must be expanding. He took a little poetic, or is it scientific, license in suggeting that the big crunch is simultaneously a re-expansion. My view is that every black hole is a big crunch. His solution may apply there as the exteriors of black holes appear to have 2-D symmetry.