Science File / an exploration of issues and trends affecting science, medicine and the environment

Q: How can Santa’s sleigh travel around the world in one night, making stops at so many houses?

A: Albert Einstein’s law of relativity proved that under the right conditions, time can dilate and space can contract, according to aerospace engineer Larry Silverberg of North Carolina State University. Silverberg believes that on Dec. 24, those conditions are fulfilled at the North Pole, which is the Earth’s center of rotation and also a point of convergence of its electromagnetic field.

When this happens, a rip literally develops in the fabric of time, allowing Santa to slip through. Until he comes back through the rip, times stands still for the rest of the world while he can take as much time as he wants to deliver the packages. “To us, it seems like the twinkling of an eye,” Silverberg said.