Steve Jurvetson · CC BY 2.0

Brian Greene co-discovered mirror symmetry in string theory, connecting geometric spaces called Calabi-Yau manifolds that had appeared unrelated, and described how the theory allows the topology of space itself to change smoothly. He has spent equal effort making that physics legible to a general audience: his book The Elegant Universe became a bestseller and an Emmy-winning NOVA series, and he co-founded the World Science Festival in 2008.