Travelling from the North Pole all around the world in one night means that the reindeer must accelerate Santa, his sleigh and all the presents up to roughly 10 million kilometres per hour, or .97 per cent of the speed of light. At that speed, air friction from the un-aerodynamic shape of the reindeer, with their antlers and legs sticking out, plus the odd-shaped presents stacked on top of the sleigh, would produce ultra-high temperatures that would incinerate Santa and his entire transport system in a matter of seconds. He would instantly become a bright meteor in the sky.