How does Santa Claus slide down so many chimneys, deliver presents to 700 million children in one single night, without being seen or heard? This mystery has now been solved by a physicist at the University of Exeter, Dr Kathy Sheen, who used Einstein’s theory of relativity to finally explain the events on the night of Christmas.
For starters, Father Christmas has to fit inside chimneys. But we all know that sliding down a chimney with a massive sack of presents without getting stuck is next to impossible. And Santa isn’t the slimmest of people around. Based on Relativity Theory, the speed Santa would need to travel to deliver all those presents to every child would shrink him or make him a lot slimmer – in the direction he is travelling. On top of that, he has to be careful not to stop for a mince pie in a chimney, or otherwise he would grow back to his original size!
Santa has been delivering presents for so many years, and yet, he always looks the same. Doesn’t Santa age? We all age, but relativity tells us that clocks slow down for the traveling subject – the faster you travel, the slower time passes. Santa and his reindeer have to travel about 10 million kilometres per hour to deliver presents to every child. Taking world time zones into account, that gives Santa roughly 31 hours to do the job. If most children have been good, and deserve bigger presents, Santa would have to travel even faster. At those speeds, Santa’s ageing process is slowed down considerably.
This gets us to one other question. Why is it so hard to see Santa? Travelling at more than 200,000 times faster than Usain Bolt (the fastest man on Earth), the laws of physics present us with another explanation.
In principle, the Doppler Effect would make Santa change colour, because the light waves released from him would get squashed at a very high speed. The Doppler Effect also makes it hard for children to hear Father Christmas. Imagine an ambulance or police car racing towards you. The siren pitch gets higher as it heads towards you, but then goes lower as it drives away – making the sound first unrecognisable, and eventually inaudible. This explains why the sound of Santa’s sleigh, the bells ringing and his deep “ho, ho, ho” would get higher as he approaches, and then go completely silent because the sound would move beyond the human hearing range.
All of this is quite an onerous task. So don’t forget to leave a mince pie or two for Santa and a few carrots for the reindeer!
This article has been republished from materials provided by University of Exeter. Note: material has been edited for length and content. For further information, please contact the source:
http://www.exeter.ac.uk/news/university/title_558233_en.html
■ The editorial team at Sounds of Science extend their warmest wishes. Merry Christmas everyone.
Did you know!
• The Germans made the first artificial Christmas trees out of dyed goose feathers.
• According to data analysed from Facebook posts, two weeks before Christmas is one of the two most popular times for couples to break up. However, Christmas Day is the least favourite day for breakups.
• Christmas trees usually grow for about 15 years before they are sold.
• Mistletoe (Viscum album) is from the Anglo-Saxon word ‘misteltan’, which means ‘little dung twig’ because the plant spreads though bird droppings.
For more trivia see: www.um.edu.mt/think
Sound bites
• Virgin Birth not Unique to Mary: Christmas, traditionally, is a giant birthday bash for Jesus Christ, who was said to be born to the Virgin Mary. The event is considered miraculous: Human biology requires sex for reproduction. But via a process known as parthenogenesis, eggs become embryos without male fertilisation. It has been found to occur in about 70 species. Recent additions to the list include komodo dragons, the world’s largest lizard and an Atlantic blacktip shark.
http://www.livescience.com/9460-female-komodo-dragon-virgin-births.html
• Artificial Intelligence Writes a Christmas Song: Researchers from the University of Toronto trained a recurrent neural network, a type of complex artificial intelligence (AI), to write a song inspired by an image of a Christmas tree. In a paper under conference review, the authors explain how they taught AI to compose tunes by feeding it 100 hours of online music. They also gave the programme thousands of images with captions so that it could link specific words to visual patterns, then create lyrics and music when provided a picture. The result is the stuff of nightmares, and you can have a listen in the link below.
http://www.livescience.com/57211-artificial-intelligence-writes-christmas-song.html
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