Endless Universe

April 9, 2007
As has happened many times in the history of science, just when we finally are able to cozy up to an idea like the big bang that initially was hard to like, let alone understand, another even more mind-bending one comes along. Steinhardt and Turok, cosmologists at Princeton and Cambridge, respectively, present their case that string theory gives a more complete account of our origins; in this account, the big bang came about through the collision of two membrane-thick strings called "branes." Our universe sits on one brane, which floats parallel to the other, unseen one. Every few trillion years, the two branes approach each other; when they collide, a flash of radiation annihilates everything in both, kick-starting the creation process all over again. According to the authors, this solves certain problems with the standard big bang theory, such as inflation, dark matter and dark energy. General readers will be able to follow the authors' clearly laid out, equation-free arguments. Their new theory has little chance of being confirmed experimentally in the foreseeable future, but many who eventually embraced the big bang will doubtless find the notion of cyclic universes and parallel worlds attractive. Illus.