Multiverse

[Jim Colyer]

[url]http://jimcolyer.com/papers/entry?id=463;fa=4[/url]

The theory that our universe may be one of an infinite number of universes has gained popularity. The idea was put forth by Alan Guth (gooth) at Sanford University in 1979. Two Russian cosmologists, Andrei Linde and Alexander Vilenkin, also take the theory seriously. According to multiverse theory, there are countless Big Bangs before and after ours. New universes are always coming into existence. Big Bangs are caused by "repulsive gravity" as energy and space-time move outward. Expansion begins with inflation, a period during which universes expand faster than light. If we could turn off all stars and galaxies, we would see a sea of radiation left over from our own Big Bang. In fact, the COBE and WMAP spacecrafts have detected and mapped this cosmic background radiation.

Alan Guth put the multiverse idea on the shelf for a while. Linde continued to publish. Multiverse proponents contend that "eternal inflation" and dark energy point to a multiverse. Each universe has a different value of dark energy. String theory, too, lends credence to a multiverse. String theory suggests that there may be more dimensions than height, width and depth. At least that is what Guth and Linde think. There may be exact duplicates of ourselves in parallel universes. Naturally, there are scoffers, scientists who believe the multiverse is science fiction. Still, there are those who think the multiverse may be the next Copernican Revolution.

Max Tegmark is a Swedish cosmologist at MIT. He thinks there are at least 4 different kinds of parallel universes and has published articles about them. High-level physics can be pretty speculative.