FRESH AIR
Our universe might be really, really big — but finite. Or it might be infinitely big. Both cases, says physicist Brian Greene, are possibilities, but if the latter is true, so is another posit: There are only so many ways matter can arrange itself within that infinite universe. Eventually, matter has to repeat itself and arrange itself in similar ways. So if the universe is infinitely large, it is also home to infinite parallel universes. Does that sound confusing? Try this: Think of the universe like a deck of cards. “Now, if you shuffle that deck, there’s just so many orderings that can happen,” Greene says. “If you shuffle that deck enough times, the orders will have to repeat. Similarly, with an infinite universe and only a finite number of complexions of matter, the way in which matter arranges itself has to repeat.” Greene, the author of The Elegant Universe and The Fabric of the Cosmos, tackles the existence of multiple universes in his latest book, The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos. Recent discoveries in physics and astronomy, he says, point to the idea that our universe may be one of many universes populating a grander multiverse. MORE