This is part of an article on cosmic collisions I read from the October 2009 Discover magazine:
While other theorists worry about the destructive power of a cosmic collision, two maverick physicists propose that such a titantic accident actually gave birth to our universe – and that what we call the Big Bang is just the latest incarnation in an infinite cycle of creation.
Paul Steinhardt of Princeton University and Neil Turok, now at the Perimeter Institute in Ontario, Canada, devised their controversial alternative to Big Bang cosmology in 2002. Their idea is based on a mathematical model in which our universe is a three-dimensional membrane, or ‘brane,’ embedded in four-dimensional space. The Big Bang, they say, was caused when our brane crashed against a neighboring one. The violence of the collision would have flooded both universes with energy and matter. These collisions should repeat every trillion years, each time triggering a new Bang and a new universe.