That's the current speculation based on the recent discovery that our universe did experience an inflation phase soon after the Big Bang. If there are other universes aside from our own, how does one prove that they exist? This question should keep many scientists fully employed for a lifetime in trying to devise potential experiments to prove this point.
http://news.yahoo.com/universe-may-exist-multiverse-cosmic-inflation-discovery-suggests-140210836.html http://news.yahoo.com/universe-may-exist-multiverse-cosmic-inflation-discovery-suggests-140210836.html