Ekpyrosis: A New Theory of the Big Bang

Most physicists when asked what came before the big bang throw up their hands. But Paul Steinhardt of Princeton and several colleagues have postulated an idea that explains everything. Unveiled at a talk given a few weeks ago at the Space Telescope Science Institute, the new theory is called the ekpyrotic model, from a Greek word meaning fiery.

The main thesis? That our present universe, filled as it is with lumpy galaxies, began as a cold featureless place which suffered a collision with another universe. This defining moment seeded our universe with the matter irregularities which would later grow into those galaxies we see in the sky.

The new theory purportedly addresses several prominent cosmological puzzles without resorting to "inflation," that hypothetical era in which the early universe expanded for a short spell at a superluminal pace. These puzzles include (1) flatness (our universe seems to have no overall curvature); (2) homogeneity (far-flung parts of the sky seem unreasonably to have roughly the same temperature); (3) lumpiness (future galaxies have to arise somehow); and (4) monopoles (expected topological defects are not seen).

A preprint summarizing the model asserts that the new idea can be put to experimental test since it makes predictions concerning gravitational waves and polarizations in the cosmic microwave background.