Santa Science. How does Santa deliver all his presents?

‘Twas the night before Christmas and all through the house, everyone was wondering how on earth Santa would manage to deliver all those presents to everyone in the world in just one night!


It’s Christmas Eve here in the UK and I’ve been getting more and more excited whilst watching Santa’s progress on the Santa Tracker. But I have been thinking to myself – how is Santa able to deliver all those gifts to around 700 million children in every country in such little time?

Now as I have a science blog I thought I could try and explain the possible science behind it, but I am definitely not a physicist but I’ll give it a go…

The theory behind Santa’s magical feat without being seen and fitting down all the different chimneys has apparently been ‘solved’ by a physicist at Exeter University.

The physicist has calculated that Santa would need to travel at about 6.2 million miles per hour to deliver all his gifts in 31 hours – taking into account all the different world time zones. Such huge speeds would make his famous red suit appear green, and at even faster speeds, it would mean he would eventually disappear. In this case, it is the Doppler effect which makes Santa change colour – which is the same effect that changes the sound of an ambulance siren whether it is behind you or in front of you! As for Santa’s red suit, it would change colour because the light waves bouncing off him get squashed due to the incredibly quick speed he is travelling at. The Doppler effect would also explain why children cannot hear Santa arrive on Christmas Eve as the sound of his sleigh and Santa shouting ‘HO HO HO’ would get higher and higher in pitch and eventually become silent as it reaches a level that the human ear cannot detect. Travelling at such quick speeds also means that Santa himself gets squished which makes it easier for him to fit down all those chimneys.

All of these effects can be linked back to Einstein’s Theory of Relativity, which was published in 1905, and says that space and time are interwoven in a single continuum known as space, but certain events could occur at different times depending on the position of the observer.


This Santa Science post also got me thinking about an exam question we had during our undergraduate degree asking us to genetically engineer Santa’s reindeer so they had wings to make delivering all these gifts easier on Christmas Eve! We had 30 minutes to anwser the question and save Christmas for the world! It was an awful exam question that we all still talk about now! At least it was memorable eh? What were some of the most memorable or worst science exam questions you?


I want to wish all my friends and family a happy Christmas and a great New Year! Thanks to everyone that has read or shared my blog this year – here is a molecular biology themed Christmas card for you all 😊🎄 Hopefully my blog will continue to grow in 2017.

Merry Christmas everyone.


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