What Universe Is this Anyway?

"Let's take a walk on the wild side and assume, for the sake of argument, that our universe is not the only one; let's say there are many others, possibly infinitely many, "out there." The totality of this bizarre ensemble is what cosmologists call the "multiverse," a hypothesis that sounds more mythic than scientific, a conceptual troublemaker that inspires some and outrages others."

"It all started in the 1980s, when physicists Andrei Linde, from Stanford University, and Alex Vilenkin, from Tufts University, independently proposed that if the universe underwent a very fast expansion early on in its existence — what is called an inflationary expansion — then our universe is not the only one."