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 ...

"There was a time when ‘universe' meant ‘all there is,' " writes Greene, but soon we may have to redefine that word, along with our own meager understanding of the cosmos. A theoretical physicist and ...

From recent theories developed to explain the behavior of subatomic particles and the dark recesses of space come the “multiverse” theory that proposes not one but an infinite number of universes. One ...