Father Christmas and his reindeer are believed to travel at incredible speeds on Christmas Eve to deliver presents to children around the world. But did you know that light from an object moving at high speeds changes colour, thanks to the Doppler effect? This phenomenon is crucial in astronomy for measuring the speed of celestial bodies.
To calculate Father Christmas’ required speed, we’ve updated a 1998 method to determine how fast he needs to travel. With approximately 690 million children believed to be on the Nice list, and 2.3 children per household worldwide, Father Christmas must visit around 300 million households across 69 million square kilometres of habitable land.
Assuming Rudolph’s nose would change colour due to speed, scientists could potentially measure Father Christmas’ speed using telescopes. By observing the colour shift caused by the Doppler effect, astronomers could infer his speed. For example, if Father Christmas were travelling at high speeds, Rudolph’s nose would appear more red or “redshifted”.
The Doppler effect is a fundamental principle in astronomy for measuring celestial movements. It has applications in detecting exoplanets and measuring galaxy distances. While the magic of Father Christmas remains unexplained, scientists are eager to use this technique to verify his speed.
Source: https://www.sciencealert.com/astronomer-calculates-true-color-of-rudolphs-nose-on-christmas-eve