December 14, 2016 3:15 PM EST

Santa Claus’s Christmas Eve journey has always required a leap of faith for believers. After all, if it takes nine hours just to get from Pittsburgh to Helsinki, no one could deliver presents to boys and girls around the world in just one night. Plus, in the age of modern technology someone would have seen Santa from a plane window or on radar and there’s no way a guy with a stomach like a “bowl full of jelly” could fit down a chimney, right? Maybe not.

A physicist has endeavored to use cold hard science to prove that Santa could in fact make the trip thanks to a little help from an unlikely source—Albert Einstein.

Dr. Katy Sheen at the University of Exeter used Einstein’s Theory of Relativity to explain how Jolly Old Saint Nick could make the trip in one night, not get caught on radar, and fit down a chimney, she presented her findings to a group of children at the university’s Science of Christmas Festival on Wednesday.

Sheen calculated how fast Father Christmas would have to travel by crunching the number of households likely to be celebrating Christmas around the world, along with the number of children likely to be in them. “Visiting around 700 million children in 31 hours would mean he would have to travel at six million miles per hour if he is to deliver presents to every child,” Dr. Sheen said in a press release. “Some strange things happen when you start to travel that fast. Firstly, time slows down. Second, Santa gets squished which means that he can fit down a chimney more easily.”

Sheen hopes her thorough explanation for Santa’s delivery system will inspire children to take a greater interest in both physics and science, and keep the magic of Christmas alive.


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