Santa’s reindeer travel at a speed of 3,604 miles per second in order to deliver presents to the world’s 2.5 billion homes, according to Anders Larsson of the Swedish engineering consultancy, Sweco. Larsson estimated there are 120 people per square mile on Earth, with 66 feet between each home. Assuming Santa is all-faith-inclusive, leaves from Kyrgyzstan, and travels against the Earth’s rotation, he has 48 hours to deliver all the presents, while spending 34 microseconds at each stop. Some scientists speculate that Santa’s sleigh, weighed down with metric tons of presents while traveling at supersonic speed, would encounter such massive air resistance it would be vaporised in a firey inferno within 4.26 thousandths of a second. Thus, the mystery of Santa’s technology lives on.