# The Physics of Santa

Santa’s Sleigh

While having lunch with The Prince yesterday, we discussed how Santa is able to get to all of the kids houses overnight. So I did some back-of-the-napkin calculations to figure out if Santa’s excursion violates causality. I should probably point out that I am neither a physicist, mathematician or doctor, but I play all of them on the Internet.

Ok, so… just how many places does Santa have to hit worldwide? According to Wikipedia (Yeah I know… and if you’re reading this and don’t know, don’t bet on facts from Wikipedia. It’s just a good starting place.), there are 2.1 billion Christians on Earth. Now, since it appears to me that most of them are in Texas, I’ll use the average family size from the U.S. Census: 3.14 people. Hmm… Pi. That means Santa has to hit 670 million homes.

Next I’ll assume that they are evenly spread across the earth. Several sources indicate that the total area is about 150 million square kilometers (The Prince says, “What’s a kilometer?” so make it 93 million square miles). That works out to 4.5 km2(1.7 mi2) per home. Now make that area circular and we get a radius of 1.2 km (.75 mi). So from house to house is about 2.4 km (1.5 mi). So the total length of the trip is 360 million km (220 million mi). That’s more than a thousand times farther than my Chevy truck has gone.

For the time, he does this overnight but if we’re figuring an even spread over the earth, he actually has 24 hours of darkness to work with if he plans his trip carefully. And if you’re going 360 million km, you plan your trip carefully, just ask NASA. That means his average speed has to be 15 million km/hr (9.3 million mph). That’s pretty fast, again, just ask NASA.

So… how fast is that compared to light speed? Light speed is 300,000 km/s which works out to be 1.1 billion km/hr, much faster than Santa. Santa ain’t Superman. But Santa is fast, 1% the speed of light fast.

This, kids, is why you can’t ever see Santa. Even if you sit up all night watching the tree you won’t see him. He’ll just wait till you blink. And by the time your blink is done, not only has he hit your house, he’s already finished with the next 260 kids.

This also explains a number of Santa Clausian phenomena. For instance, what if you have a roaring fire in the fire place? Why doesn’t Santa get burned? Well, at 1% the speed of light within the atmosphere, it’s obvious that Santa has some fantastic thermal protection for his sleigh and reindeer. The space shuttle heat tiles get up to 1300°C (2300°F) at a speed far less than Santa’s sleigh. You would have to be seriously pumping a bellows into the coals in your fireplace to get it that hot. So a fire is nothing for Santa’s thermal suit.

How come he doesn’t get dirty in the fireplace? Well, considering that Santa’s sleigh doesn’t cause a sonic boom, it’s clear that part of his technology involves moving without disturbing the air. Basically, he doesn’t stir the air, so it’s like he never touches it at all. If he can do that, he also doesn’t touch the soot either.

Don’t have a fireplace at all? No problem. Every home has many small entry ways, vent pipes, dryer exhausts, range hoods, etc. Yeah but how does fat jolly old Santa fit through them, you say? Easy, for a brief moment (by brief, I mean like fast enough that he can do it a million times while you’re in the middle of a blink…) he accelerates to a substantial fraction of the speed of light and spirals in through the opening however small it is. The Lorentz contraction allows him to be smaller than the hole to get through.

Rudolf’s red nose? Simple, just let enough heat through the shielding and you get a nice red glow. Actually it could glow any color you like at those speeds, even X rays.

Those craters on the Moon? (If you read that and thought “Huh??”, good, you’re paying attention.) Not all of them are meteor strikes. Ever wonder why only the reindeer have the magic flying dust? Well, it’s because the dust is DANGEROUS! During early testing, many dozens of Santa candidates tried flying without the reindeer. They took a little dust, tried taking a little bitty step, and BOOM! right into the moon! That’s how they named the craters (Wikipedia-List of Craters on the Moon). Finally, someone discovered that reindeer are patient enough to keep the speed down to 0.01c.

This is also why NORAD couldn’t possibly have shot Santa down. Let’s say your reflexes are fast, very fast. So you can acquire your target and squeeze the trigger in 1/100th of a blink. Santa’s already moved 6 km (4 mi) down range. Even if you led the target perfectly, his slightest evasion move will out pace any modern weaponry we have. And remember, he can surge to very much higher speeds to make himself small. In his time frame it looks like the missile you just shot at him is stuck in molasses. He has time to read a bedtime story to the reindeer while your missile gets out of the launcher.

E.W.

It was either “Santa Clausian” or “Kris Kringelian”, I knew he was Klingon…

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