The idea that our universe may be one of an infinite number of universes has gained popularity. American Alan Guth (gooth) and Russian Andrei Linde are believers. According to the multiverse theory, there are an infinite number of Big Bangs. New universes are forever coming into existence. Expansion begins with inflation, a period during which universes expand faster than light. If we could turn off the galaxies, we would see a sea of radiation left over from our Big Bang. In fact, the COBE and WMAP spacecraft have mapped this Cosmic Background Radiation.
Alan Guth shelved the idea for a while, but Linde stayed with it. Believers contend that dark energy points to a multiverse. They say string theory, too, lends credence. String theory suggests that there may be more dimensions than height, width & depth. There may be duplicates of ourselves in parallel universes. Naturally, there are scoffers, cosmologists who think the multiverse is fantasy.
It is getting hard to tell the difference between science and science fiction. Swedish cosmologist Max Tegmark claims there are 4 kinds of parallel universes.
Alan Guth was born in 1947, and a prime candidate for the Vietnam War. He enrolled in a 5-year program at the Massachusetts Institute of Technology (MIT) apparently to stay out of Vietnam. I cannot blame him. I did not want to go to Nam either.