It only takes a physicist to debunk the Santa Claus legend.
No known species of reindeer can fly. However, it is estimated that there are still around 300,000 species of living organisms waiting to be classified; and although most of these species are insects or germs, this does not completely rule out the possibility of flying reindeer that only Santa Claus has encountered so far.
There are nearly two billion children on Earth (counting people under 18). Since Santa Claus doesn’t seem to care about Muslim, Hindu, Jewish, and Buddhist children, this reduces his workload to 15% of the total – that is, 378 million children, according to the American Population Reference Bureau. With a statistically average number of 3.5 children per household, that makes 91.8 million households. For the purposes of our further calculations, let’s assume that there is at least one good child in every house and that Santa Claus gives a present to every child, even if they haven’t been good all year.
Santa Claus has 31 hours to work at Christmas, thanks to the different time zones and the Earth’s rotation. Let’s assume he travels from east to west; at least, that seems logical. Based on this, Santa Claus has to visit 822.6 houses per second. This gives us the information that Santa Claus has slightly more than one thousandth of a second to stop at a Christian household with a good child, get off his sleigh, climb down the chimney into the house, fill the stockings or boots, put the presents under the Christmas tree, eat all the food left for him, climb back down the chimney, get on his sleigh, and travel to the next house. Let’s assume that all 91.8 million households to be visited are equidistant from each other (which, as we know, is of course incorrect; but we’ll simply assume it for this calculation), and set the average distance at just under 1.25 kilometers (calculated based on the area of the countries visited). This results in a travel distance of approximately 120 million kilometers, disregarding stopovers for certain errands that each of us has to run at least once in 31 hours. This, in turn, means that Santa’s sleigh travels at 1,046 kilometers per second, which is about 3,000 times the speed of sound. Just for comparison: the fastest man-made vehicle, the Ulysses space probe, moves at the tiny speed of 44 kilometers per second. A normal reindeer can run at a maximum of 25 kilometers per hour.
The total weight of the sleigh is another interesting element in our analysis. Let’s assume that each child receives no more than an average Lego set weighing approximately 900 grams. In that case, the sleigh would have to withstand a load of about 340,200 tons, not including Santa Claus himself, who is often described as being quite overweight—how could he be otherwise, considering all the sweets he has to eat along the way? In the countryside, a normal reindeer can pull no more than 135 kilograms. Even if we assume that a „flying reindeer“ (see point 1) could withstand ten times the conventional load, this work could not be done by eight or nine animals. We would need approximately 252,000 flying reindeer. This, however, increases the total weight (not including the sleigh’s own weight) to around 374,220 tons.
To put this in perspective: that’s more than four times the weight of the luxury liner „Queen Elizabeth.“
When 374,220 tons move at a speed of 1,046 kilometers per second, it creates enormous air resistance. This would heat the reindeer in the same way as a spacecraft re-entering the Earth’s atmosphere. The first pair of reindeer pulling the sleigh would each absorb approximately 14.3 quintillion joules of energy per second. Within a very short time, they would burst into flames and explode instantly, subjecting the following pair to the same stress and leaving behind a deafening sonic boom. The entire reindeer team would vaporize within 4.26 thousandths of a second. Meanwhile, Santa Claus would be subjected to centrifugal forces approximately 17,500 times greater than normal gravity. A 135 kg Santa Claus (which would be ridiculously thin) would be pressed onto the floor of his sleigh with a force of approximately 1,957,290 kg.
As a result, one could say: