Endless Universe

Endless Universe: Beyond the Big Bang by Paul J. Steinhardt and Neil Turok
Instead of a "big bang" where time and space sprang into existence 14 billion years ago, the authors postulate a cyclical universe that has always existed and will continue to exist. The authors theorize there have been countless big bangs -- calling this M theory. This theory says the universe contains objects called "branes" (short for membranes). Two branes engage in an endless cycle of "collision, rebound, stretching and collision again."
I understand virtually nothing of the rationale behind this new theory except that it is intriguing to me that this theory apparently answers the multitude of questions/problems that arise when considering the Big Bang model. Even Stephen Hawking calls it "a challenging alternative to the accepted picture of the Big Bang and the future of the universe."