"I believe the closest non-related evidence for multiple universes right now comes from the physics (derived from special relativity) of rotating (Kerr) black holes" - John Titor
I've reading about what Kip Thorne has been doing recently. He's been detecting gravitational waves coming from what he calls "black hole mergers". He mentioned that the guys in the relativity suite said that he might have found something profound but they didn't say what