On Fri, 10 Oct 2003, Meeussen Wouter (bkarnd) wrote:
when will we get some good data for the gravitational constant G ? CODATA's G= 6.67259 10^-11 m^3kg^-1 s^-2 is not exactly blowing my socks off.
...and let me say, really in response to one of M.Kleber's messages, that the continued assertion that the universe is extremely flat no longer produces any detectable disturbance of my own socks, because it's apparently not even known to be flat enough to rule out the curvature that would be appropriate for a closed spherical or hyperbolic universe of size about what we can observe. However, that's comforting in a way, because it still lets us dream about the "dodecahedral" possibility. I put that adjective in quotes because it's really a misnomer, there being no invariant dodecahedron in the space. There is a way to construct dodecahedra - namely in the universal cover, the Voronoi cells determined by the 120 preimages of any point are dodecahedra - but isn't that a bit too recondite? One point that I never see discussed when the shape of the universe comes up is what it implies for the shape of space-time. In particular, the "dodecahedral" possibility seems to restore the "unique factorization" into space x time that we thought we'd lost when Relativity came along. Is there a shape for space-time that makes space compact but that doesn't have an invariant factorization as space x time? John Conway