January 16, 2008
WHY SHOULD THE FIBROMYALGIC HAVE ALL THE FUN:
Ekpyrotic cosmology resurfaces (Physics World, 1/15/08)
In ekpyrotic cosmology — which was proposed in 2001 by physicists Paul Steinhardt, Justin Khoury, Neil Turok and Burt Ovrut — there is no beginning of time. Instead, our visible universe exists on one of two four-dimensional “branes” floating in a five-dimensional space. These two branes are locked in an endless oscillatory motion in which they creep together, “bounce” through each other, withdraw and then creep together again (see animation: Branes collide). At each bounce, which is like a fresh Big Bang, ripples in the branes collide and liberate energy at different places to produce the initial density perturbations. And because energy conservation would favour a flat brane, the theory explains why our visible universe is flat too. “It’s like the antichrist to inflation,” says Khoury.
Past critics of ekpyrotic cosmology, however, have highlighted two particular problems. First, every bounce would be a point of infinite temperature and pressure known as a singularity, which is impossible to describe using conventional physics. Second, it was not clear that the density perturbations would be present on all length scales, as observations of the primordial radiation left over from the Big Bang — that is, the cosmic microwave background — indicate they should be.
Third: put down the crack pipe and embrace your ignorance. Posted by Orrin Judd at January 16, 2008 10:51 AM