
The Physics of Santa Claus(1) No known
species of reindeer can fly. But, it is estimated that there are 300,000 species
of living organisms yet to be classified. Most
of these are believed to be insects and germs, but this does not completely rule
out flying reindeer. (2) There are 2
billion children (persons under 18) in the world. But since Santa doesn’t
appear to handle the Muslim, Hindu, Jewish and Buddhist children, that reduces
the workload to 15% of the total378 million according to the Population
Reference Bureau. At an average census rate of 3.5 children per household,
that’s 91.8 million homes. One
presumes there’s at least one good child in each. (3) Santa has 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 822.6 visits per second. This is to say that for each
Christian household with good children, Santa has 1/1000^{th} of a
second to park, hop out of the sleigh, jump down the chimney, fill the
stockings, distribute the remaining presents under the tree, eat whatever snacks
have been left, get back up the chimney, get back into the sleigh and move on to
the next house. Assuming that each of these 91.8 million stops are evenly
distributed around the earth, which, of course, we know to be false but for the
purposes of our calculations we will accept, we are now talking about 0.78 miles
per household, a total trip of 751/2 million miles, not counting pottie stops,
plus feeding, etc. (4) This means
that Santa’s sleigh is moving at 650 miles per second, 3,000 times the speed
of sound. For purposes of comparison, the fastest manmade vehicle ever, the
Ulysses space probe, moves at a pokey 27.4 miles per second through the vacuum
of deep space. A conventional reindeer can run, by the way, tops, 15 miles per
hour. (5) The payload on
the sleigh adds another interesting element. Assuming that each child gets nothing more than a
mediumsized Lego® set (2 pounds), the sleigh is carrying 321,300 tons, not
counting Santa, who is invariably described as overweight. On land, conventional
reindeer can pull no more than 300 pounds. Even if we assume that “flying
reindeer” could pull ten times the normal amount, we cannot do the job with
eight, or even nine. We would need 214,200 reindeer. This increases the payload
not even counting the weight of the sleighto 353,430 tons. Again, for
comparison, this is four times the weight of the Queen Elizabeth (the cruise
ship, not the monarch herself). 6) 353,000
tons traveling at 650 miles per second creates enormous air resistance. This
will heat the reindeer up in the same fashion as a spacecraft’s heat shield
when reentering the earth’s atmosphere. The lead pair of reindeer will absorb
14.3 quintillion joules of energy. Per
second. Per reindeer. In short, they will burst into flames almost
instantaneously, exposing the reindeer behind them, and create deafening sonic
booms in their wake. The entire reindeer team will be vaporized within 4.26
thousandths of a second. Santa, meanwhile, will be subjected to centrifugal
forces 17,500 times greater than that of gravity. A 250pound Santa, which seems
ludicrously slim, would be pinned to the back of his sleigh by 4,315,015 pounds
of force. In summary, the Santa story, while not disproved, should be
viewed with some skepticism in light of all of the considerable physics problems involved. 