Dr. Laura Driessen is a radio astronomer at the University of Sydney. At Study Finds, she explains that the speed of an object in motion affects sound and light waves from that object relative to an observer. This is called the Doppler Effect.
Rudolph the Red-Nosed Reindeer, who leads Santa's sleigh with his nose so bright, has a red-appearing nose only when he is motionless. The appearance of his nose changes when he travels at speeds sufficient to complete his busy night of work.
Dr. Driessen estimates that Rudolph must travel at 8.2 million KPH in order to deliver Santa to each of his destinations. If you saw Rudolph moving toward you, his nose would appear bright orange. If you watched him fly away, his nose would turn almost black.
