On the Seventh Day of Advent — SANTA CLAUS: THE DEFINITIVE SURVEY
From The Guardian, 24th December 1991
Armed with just a sleigh and a reindeer, he allegedly delivers toys to children the world over.  Using computers, we assess if it is physically possible.
Do you believe in Santa Claus?  This is a complex theological question that each child must decide for him or herself.  Until now, that is.  With the aid of computers, we have conducted a rigorous statistical investigation into the question of Santa’s existence.
We begin by assuming that Santa Claus really does exist.  Now, if you’ve learned anything about human nature, you know it’s highly unlikely that a normal man would choose to devote his life to making toys and delivering them to boys and girls the world over.  But this is an objective enquiry, and questions of motivation aren’t relevant.  We want only to know whether such a man could accomplish his mission.
Santa’s first obstacle is that no known species of reindeer can fly.  However, scientists estimate that out of the earth’s roughly two million species of living organisms, three hundred thousand or so have yet to be classified. So we can’t rule out the slight possibility that a species of reindeer does, in fact, exist.  And that no one besides Santa has ever seen one.
A bigger obstacle for Santa is that there are two billion children under eighteen in the world.  The good news is that he needs to deliver presents only to Christian children, of whom there are approximately three hundred and seventy-eight million.  Let’s assume that fifteen percent of these Christian children are bad and thus — like Muslim, Hindu, Jewish and Buddhist children — ineligible for gift-getting.  Still at an average of three point five children per household, Santa has a back-breaking ninety-one point eight million homes to visit on any given Christmas Eve.
Fortunately, Santa has thirty-one hours of Christmas Eve darkness to visit all these homes if he travels from east to west, thanks to the rotation of the earth.  Unfortunately, this still works out to eight hundred and twenty-two point eight visits per second.  So, for each Christian household with good children, Santa has just over a thousandth of a second to land, hope out of his sleigh, jump down the chimney, fill the stockings, distribute the rest of the presents under the tree, eat whatever snacks have been left out, get back up the chimney, climb back into his sleight, take off and fly to the next house.
How fast is Santa moving?  Assuming all ninety-one point eight million stops are spread evenly over the earth’s landmass, Santa must travel nought point seven nine miles per household — a total trip of seventy-two million, five hundred and twenty-two thousand miles.  (This is a conservative estimate.  It doesn’t include trips across oceans, feeding stops for the reindeer, etc.)  Given the thirty-one hour time period, Santa’s sleigh must maintain an average speed of six hundred and fifty miles per second, or more than three thousand times the speed of sound.  To give you an idea how fast that is, the fastest man-made vehicle ever built, the Ulysses space probe, travels at a relatively poky pace of twenty-seven point four miles a second, and conventional, land-bound reindeer travel at a top speed of fifteen miles per hour.  But let’s just assume that Santa’s flying reindeer can somehow reach hyper-sonic speeds — thanks, say, to the magical spirit of Christmas giving.
Let’s take a close look at Santa’s vehicle.  First of all, assuming a cheapo two pounds of presents per child (that’s like the crummy Lego set), the sleigh must still be able to carry a load of three hundred and twenty-one thousand, eight hundred tons — plus Santa, an overweight man.  On land, a reindeer can’t pull more than three hundred pounds of freight and, even assuming that flying reindeer can pull ten times that amount, Santa’s massive sleigh has to be drawn by two hundred and fourteen thousand, two hundred beasts.  They increase the overall weight of the Santa payload to three hundred and fifty-three thousand, four hundred and thirty tons (not including the weight of the sleigh itself).  This is more than four times the weight of the Queen Elizabeth ocean liner.  Imagine: Santa skimming over rooftops in a gargantuan hypersonic aircraft with even less manoevrability than a Big Wheel.
Here’s where things get fun.  Three hundred and fifty-three thousand tons of reindeer and presents are going to create an enormous amount of air-resistance — especially at six hundred and fifty miles per second.  This air-resistance will heat the reindeer in the same way that spaceships are heated up when they re-enter the earth’s atmosphere.  According to our calculations, the lead pair of reindeer will absorb fourteen point three quintillion joules of energy per second each.  This means they will burst into spectacular, multicolored flames almost instantaneously, exposing the reindeer behind them.  As Santa continues on his mission — leaving deafening sonic booms in his wake — charred reindeer will constantly be sloughed off.  All two hundred and fourteen thousand, two hundred reindeer will be dead within four point two six thousandths of a second.

As for Santa, he will be subject to centrifugal forces seventeen thousand, five hundred point nought six times greater than gravity.  A two hundred and fifty pound Santa will be pinned to the back of his sleigh by four million, three hundred and seventy-five and fifteen pounds of force (after we deduct his weight).  This force will kill Santa instantly, crushing his bones, pulverizing his flesh, turning him into pink goo.  In other words, if Santa tries to deliver presents of Christmas Ever to every qualified boy and girl on the face of the earth, he will be liquefied.  If he even exists, he’s already dead.