“There are many of us thinking of one version of parallel universe theory or another. If it's all a lot of nonsense, then it's a lot of wasted effort going into this far-out idea. But if this idea is correct, it is a fantastic upheaval in our understanding.”

American physicist, professor, and science festival chairman

Brian Greene is an American physicist and professor of physics and mathematics at Columbia University. He is known for his work on string theory and for co-founding the World Science Festival in 2008. He directs Columbia’s Center for Theoretical Physics and serves as chairman of the festival. Greene also co-discovered mirror symmetry, a relation between two different Calabi-Yau manifolds, and described the flop transition and the conifold transition, showing how topology can change smoothly in string theory.