“Astrophysicist Neil deGrasse Tyson tongue-in-cheekily tells Morning Edition's David Greene that the whole bit about flying around the world in a sleigh pulled by reindeer and landing on rooftops is just a ruse. He says that what St. Nick is really doing, if you think about the "science of Santa," is whipping around the world and into the homes of good girls and boys via some wondrous wormholes.”