On Friday, October 10, 2003, at 09:00 AM, John Conway wrote:
Well, yes, I'd be delighted too. But what puzzles me about this idea is that that kind of universe, being a quotient of a sphere, has positive curvature, which contradicts the observation that the universe is very very flat. [...]
The WMAP initial data has given the best measurement in existence of just how flat the universe is. Omega_0, the density, is exactly 1 in a flat universe, >1 for spherical and <1 for hyperbolic. The initial best match WMAP data puts Omega_0 at 1.02 +- .02. Further data to appear within the next six months ought to narrow down the interval to about a tenth of that size, I think. The dodecahedral space hypothesis is based on matching the harmonics, and with the best match there, its positive curvature predicts an Omega_0 of 1.013. (So the upcoming improved Omega_0 data will either bolster or shoot down this idea.)
[...] So I think the idea is nonsense.
I've heard a cosmologist say, approximately, that anyone who thought anything about the universe, and hasn't updated that thinking in light of the WMAP data, should now be considered a historical relic. Confidence intervals for cosmological constants have changed from "within an order of magniture" to "+- 2%" in the past year. O brave new world... --Michael Kleber kleber@brandeis.edu