The Physics of Christmas: How Could Santa Visit the Whole World in Just 24 Hours?

Santa Claus’s annual gift-giving journey is a feat that has long captivated the imagination of children and adults alike. But while it’s not necessarily rooted in science, is it in fact possible? Let’s break down the monumental task facing jolly old St. Nick and explore the mind-boggling physics behind his globe-trotting gift delivery.

With the awesome power of science and perhaps a sprinkling of Christmas stardust, let’s look at the frightening feat facing Father Christmas. Will he get it all done in time?

Spoiler: Of course he will, he always does!

When you boil it down, the task is pretty simple. Santa Claus and his nine reindeer – Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen, and Rudolph – have to deliver presents to children all over the world on Christmas Eve.

However, when you find out how many homes they have to visit, how far and how fast they have to travel, and how many servings of milk and cookies he has to eat, the job gets a little more complicated.

Well, a lot more complicated.

For these calculations, we’re going to have to make some assumptions. Back in 2018, three physics students from the University of Leicester did some maths. They estimated that there are around 715 million Christian children around the world, and assuming an average of three per household, Santa is going to have to visit somewhere around 238 million homes.

Now, those 238 million homes aren’t all next door to each other (we wouldn’t like to be the postman lumbered with that particular round). They’re spread over an area of roughly 30 million square kilometres (11.5 million square miles), so he’ll need to cover a distance of about 160,000,000 km (99.4 million miles) – farther than the distance from Earth to the Sun.

Luckily for Santa, he has a little more than the standard 24 hours to play with. Starting at the International Date Line and working east to west, he has between 31 and 34 hours to complete his monumental mission, thanks to the earth’s rotation, variations in the times of sunrises and sunsets (and childrens’ bedtimes), as well as different locations and latitudes. But, assuming we give him the maximum available time of 34 hours, or 2,040 minutes, or 122,400 seconds, then how fast does he actually have to travel?

To recap, we know Santa has to visit 238 million homes, and he’s got 34 hours to do it. So, he’s going to have to visit seven million households per hour, 116,667 households per minute, or 1,944 households every second.

A hard enough job as it is, but it gets even harder when you take into account that at each house, Santa has to decelerate from staggeringly high speeds, get off his sleigh and get into each house undetected (very few houses these days have chimney flues), he has to deliver all the presents, eat the cookies and drink the milk, get back out of the house undetected, back on his sleigh, and accelerate to the same high speeds. He may have to do all this, at each house, in under two microseconds (that’s two millionths of a second).

Now we come to Santa’s speed. He needs to travel 160 million kilometres in 34 hours, which is around 4.7 million kilometres per hour, or 0.44% of the speed of light, way beyond our current technical capabilities, but it’s Santa, so anything’s possible….

In a journey of such magnitude, there are a few logistical challenges to overcome…

Air Resistance: At such colossal speeds, the air resistance would be enough to vaporise Santa, his sleigh and all the presents.

Payload: Santa’s sleigh would need to carry presents for hundreds of millions of children. The weight of books, toys, bikes, games consoles and chocolate would be enormous, requiring an extraordinary amount of energy to move.

Navigation: Santa would need a seriously sophisticated sat-nav system to visit every home efficiently without going to the same house twice. Not great for Santa, not too bad for the kids who get two lots of presents!

Aerodynamics: The University of Leicester students calculated that Santa’s sleigh would need aerofoils of approximately 1.26 x 10-3 m² to stay airborne at these speeds. That’s some seriously magical engineering!

Several scientific concepts could potentially explain Santa’s ability to get to each house –

Time Dilation: At speeds approaching that of light, time would slow down for Santa relative to Earth, effectively giving him more time to complete his journey.

Wormholes: These theoretical shortcuts through space-time connecting distant points could allow Santa to cover vast distances almost instantaneously.

Quantum Superposition: Santa might exist in multiple places simultaneously, delivering gifts to millions of homes at exactly the same time.

Artificial Intelligence: Advanced AI could help Santa optimise his route and manage gift requests efficiently.

Super-Advanced Sleigh Technology: His sleigh may use ultra-futuristic tech, letting it zip around at impossible speeds and drop presents invisibly. Think of it as a super-fast, high-tech delivery drone.

So each year, as children around the world drift into dreams filled with expectation, Santa embarks on his extraordinary voyage, defying logic and time to deliver joy. And while the physics of Santa’s journey may seem impossible, perhaps that’s what makes the magic of Christmas so special.