The fastest things on Earth

SANTA'S work schedule is short but intense. To deliver gifts to all the world's 2.1 billion children on a single day he has to travel at 4,680,000 miles per hour, or around Mach 6,000. Never mind that at that speed the reindeer would be ripped apart by centrifugal forces. Father Christmas outpaces the fastest mortals and their contraptions (whose speed we faithfully plot across one mile*). The X-15, a rocket-powered aircraft, moves about a thousand times slower than Saint Nick's sleigh. The fastest that man has ever travelled was returning from the moon in 1969. A bird is faster than a fish, which is faster than the fastest land animal. Humans are laggards. The fastest on foot, aptly-named Usain Bolt, can’t even outrun a four-legged robot—though real cheetahs are for now more than twice as quick as their mechanical counterparts. Select the icon to see the speed record holder; press play for the race to begin.

* Santa's speed, calculated by Roger Highfield, a science journalist, is merely representative; browsers cannot yet render images at 6,000 times the speed of sound. The Apollo 10 capsule is depicted falling vertically, but in reality reached peak speed entering the Earth’s stratosphere horizontally. More on the physics of Christmas is here.