The sleigh of the one and only Santa Claus, that jolly old demigod, is a vehicle which brings joy wherever it goes. Pulled by eight reindeer who drink from the waters of The River Without End, the sleigh enables Old Saint Nick to deliver gifts to each and every believer on the planet. But what appears to us to be a one-night affair is in fact a non-stop, day-in and day-out job. Yes, he can travel through time and space thanks to his reindeer and the waters they imbibe on a regular basis, but there’s still a whole lot of us who are waiting on him each Christmas. And a dude needs to sleep once in a while. So he paces himself and works nine to five. Just like so many of us.
And just like Dolly Parton. Yes, I said it. Santa is just like Dolly Parton.
Now, there is a popular meme we should address here which attempts to debunk the existence of Santa and his sleigh. This has been floating around since even before the Internet was a thing—it was passed around via folded up photocopies during the middle school days of Michael Silver and his ilk in the early 1990s, for instance. But this “Engineer’s Perspective” is riddled with inaccuracies, which we will address here one at a time.
There are approximately two billion children (persons under 18) in the world. However, since Santa does not visit children of Muslim, Hindu, Jewish or Buddhist religions, this reduces the workload for Christmas night to 15% of the total, or 378 million (according to the Population Reference Bureau). At an average (census) rate of 3.5 children per house hold, that comes to 108 million homes, presuming that there is at least one good child in each.
There is no such thing as a “bad” child, at least not in the mind of Mr. Kris Kringle himself. And the man does not discriminate based on religion; he delivers to any and all who believe in him. He also delivers to more than just children. So, this is all wrong.
Santa has about 31 hours of Christmas to work with, thanks to the different time zones and the rotation of the earth, assuming he travels east to west (which seems logical). This works out to 967.7 visits per second.
This is to say that for each Christian household with a good child, Santa has around 1/1000th of a second to park the sleigh, hop out, jump down the chimney, fill the stockings, distribute the remaining presents under the tree, eat whatever snacks have been left for him, get back up the chimney, jump into the sleigh and get on to the next house. Assuming that each of these 108 million stops is evenly distributed around the earth (which, of course, we know to be false, but will accept for the purposes of our calculations), we are now talking about 0.78 miles per household; a total trip of 75.5 million miles, not counting bathroom stops or breaks. This means Santa's sleigh is moving at 650 miles per second --- 3,000 times the speed of sound. For purposes of comparison, the fastest man-made vehicle, the Ulysses space probe, moves at a poky 27.4 miles per second, and a conventional reindeer can run (at best) 15 miles per hour.
None of this takes into account the ability of Santa to use the sleigh and its reindeer to pierce The Veil of the World, which allows him to travel instantaneously between any two rivers in the universe—and to any point in time when those rivers were flowing.
The payload of the sleigh adds another interesting element. Assuming that each child gets nothing more than a medium sized Lego set (two pounds), the sleigh is carrying over 500 thousand tons, not counting Santa himself. On land, a conventional reindeer can pull no more than 300 pounds. Even granting that the "flying" reindeer could pull ten times the normal amount, the job can't be done with eight or even nine of them --- Santa would need 360,000 of them. This increases the payload, not counting the weight of the sleigh, another 54,000 tons, or roughly seven times the weight of the Queen Elizabeth (the ship, not the monarch).
Santa’s bag itself weighs little more than a few pounds. The payload is kept in a pocket dimension accessed by reaching into the bag.
600,000 tons traveling at 650 miles per second crates enormous air resistance --- this would heat up the reindeer in the same fashion as a spacecraft re-entering the earth's atmosphere. The lead pair of reindeer would absorb 14.3 quintillion joules of energy per second each. In short, they would burst into flames almost instantaneously, exposing the reindeer behind them and creating deafening sonic booms in their wake. The entire reindeer team would be vaporized within 4.26 thousandths of a second, or right about the time Santa reached the fifth house on his trip. Not that it matters, however, since Santa, as a result of accelerating from a dead stop 650 m.p.s. in .001 seconds, would be subjected to centrifugal forces of 17,500 g's. A 250 pound Santa (which seems ludicrously slim) would be pinned to the back of the sleigh by 4,315,015 pounds of force, instantly crushing his bones and organs and reducing him to a quivering blob of pink goo.
We know it’s the wrong Tim Allen character to quote here—his Scott Calvin from The Santa Clause would be more appropriate here—but we can't resist quoting Buzz Lightyear in this moment and telling the person who wrote this originally, “You are a sad, strange, little man, and you have my pity.”
Therefore, if Santa did exist, he's dead now.
No, he is very much alive. And his sleigh is a very big part of that. Oh, and the reindeer too.