Superstring theorist Brian Greene describes nine different theories which imply that we are living in a vast multiverse. He's pretty confident that some of them are true, but less sanguine about others. One important takeaway, though, is what he calls the "Copernican pattern": over the past 500 years, each new cosmological discovery has removed us from being in a privileged position in the universe. ... Greene takes this further: what we call our universe is only one piece of an unbelievably vast multiverse.