AN ENGINEERING CHRISTMAS….
July 12th, 2005
A Christmas Engineering Calculation
Finally - something for the Engineers in DRS
I. There is approximately two billion children–persons
under 18–in the world. But, since Santa is not supposed
to visit non-Christian children, his Christmas Eve work-
load is limited to 15% of the total, or 378 million
children–according to the Population Reference Bureau.
At an average of 3.5 children per household, that comes
to 108 million homes, presuming that there is at least
one “good” child in each.
II. Assuming Santa travels east to west, which seems logical
considering the earth’s rotational direction, he has
about 31 hours in which to complete his gift-distribution
task. This works out to 967.7 visits per second, leaving
him about .001 of a second to park his sleigh at each
“good” child’s house, hop out, zip down the chimney,
fill the stockings, distribute the remaining present
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, he would have to cover about 0.78 miles between
each pair of houses, a total of 75.5 million miles, not
counting potty stops or rest breaks. His sleigh would
have to move at 650 miles per second–3,000 times the
speed of sound. For comparison, the fastest man-made
vehicle, the Ulysses space probe, moves at a mere 27.4
miles per second. Incidentally, a normal reindeer can
run no faster than 15 miles per hour, so Santa’s would
have to be quite gifted as track stars.
III. The sleigh’s payload adds another interesting element.
Assuming that each child gets only a medium-sized Lego
set (two pounds), the sleigh would be carrying over
500,000 tons, not counting Santa himself. On land, a
conventional reindeer can pull no more than 300 pounds.
Even granting that a “flying” reindeer could pull ten
times the normal amount, the job couldn’t be done with
eight or even nine (remember Rudolph) of them. Santa
would need 360,000 normal reindeer, increasing the total
moving mass-not counting the weight of the sleigh–by at
least another 54,000 tons, or roughly seven times the
weight of the QEII (Queen Elizabeth II ocean liner).
IV. Over 550,000 tons traveling at 650 miles per second
encounters enormous air resistance, creating a deafening
sonic boom and heating 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. In short, they would burst
into flames almost instantly, exposing the pair behind
them to the same consequences. The entire eight-reindeer
team would be vaporized within .00426 of a second, or
right about the time Santa reached the fifth house on
his tour. Not that it would matter, since Santa, having
accelerated from rest to 650 m.p.s. in .001 of a second,
would have been subjected to a centrifugal force of
17,500 g’s. A 250 pound Santa 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 genuine “bowl full of jelly,” whether laughing
or not.
V. Therefore, if Santa ever existed, he’s been dead for quite
a while, but he lives in our hearts forever