With around two billion children waiting for presents tonight, scientists say Santa would need to make a journey equivalent to flying to the sun in just one evening.
The main conceptual idea of the text is that, to deliver presents to all the children on Earth in one night, Santa would need to travel at a speed incredibly close to the speed of light. The text explains that this speed, around 0.8% of the speed of light, is estimated by scientists based on the amount of time Santa has and the distance he needs to cover. Interestingly, the text also mentions that at such a high speed, Rudolf's famous red nose wouldn't appear red due to a phenomenon predicted by Einstein's theory of special relativity called length contraction. Essentially, objects moving at near-light speeds appear compressed in size from the perspective of a stationary observer. This means that the wavelengths of light emitted by Rudolf's nose would be compressed, shifting its appearance to a different color, possibly even making it appear colorless.
