M theory is the Membrane theory. It is the theory that our universe is a bubble floating within an infinite realm of other universes. In M theory, there are 11 dimensions. 10 spacial and 1 time. M theory suggests that for every outcome in an occasion, there is a universe where that outcome took place. For instance, M theory suggests that if you figured out a way to go back in time (its possible), and changed an event, that it would only take effect in a whole different universe. If you were to travel back to your time after making the change, nothing would have changed. The only change would be in the new universe. However, there would also be entirely new universes with perhaps different laws of physics. That also might explain the Big Bang theory. Perhaps the collision of two other universes lead to the creation of our universe?