World History and Science: Ask Michio: If parallel universes exist, can they collide?

I have discovered Michio Kaku. He is a great explainer of science to the layman. Try the explanation below to see if it doesn't explain cosmology better than you knew it before.

This is the first time I have heard about the Big Splat. Michio Kaku's link is

mkaku.org

If parallel universes exist, can they collide?
Matthew
England

Michio: Probably. The latest cosmological data comes from the WMAP satellite currently orbiting the earth. The data is consistent with “inflation,” i.e. the idea that the universe began in a super turbo-charged expansion at the instant of the big bang. However, inflation is also a quantum theory, i.e. there is a finite probability that if inflation happened once, it can happen again, and again. In fact, big bangs may be happening all the time, even as you read this sentence. There may be a continual creation of universes.

In other words, our universe is probably a bubble of some sort which is expanding. But inflation theory seems to indicate that we may not be the only bubble/universe. Think of a bubble bath, in which there are innumerable soap bubbles floating, sometimes colliding, sometimes breaking in half, sometimes popping in and out of existence. This is the “multiverse” picture which seems to be emerging from inflation theory.

Inflation theory, however, cannot explain the dynamics of these bubble/universes. Inflation simply states that such a turbo-charged expansion took place, but inflation does not explain why inflation took place in the first place, or what drives it. For that, we need a higher theory, such as string theory (or its latest version, M-theory, where M stands for membrane).

In M-theory, there are innumerable membranes floating in a much larger arena (11 dimensional hyperspace). We live on the skin of one such bubble which lives in 3 dimensional space. However, there may be other “branes” floating in 11 dimensional hyperspace. The physicists at Princeton calculated what would happen if two such branes collided. Much to their surprise, they found that the two branes would merge and create a shock wave. By analyzing this shock wave, they found that it resembled the big bang itself. In fact, they were led to believe that this WAS the big bang. This theory is now called the Big Splat theory, and is one of the serious candidates for the underlying big bang theory.