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 (except maybe in
Japan) 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 household, that comes to 108 million homes, presuming there is at least
one good child in each.

Santa has about 31 hours of Christmas to work with, thanks to the different time zones
and the rotation of the earth, assuming 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 stocking, 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 onto
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.

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 thousands tons, not counting Santa himself. On land, a conventional reindeer can pull
no more than 300 pounds. Even granting that the "flying" reindeer can pull 10
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).

600,000 tons traveling at 650 miles per second creates 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 adsorb 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
to 650 m.p.s. in .001 seconds, would be subjected to acceleration forces of 17,000
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. Therefore, if Santa did exist, he’s
dead now.

Merry Christmas!

Physics refutes this. From "New Scientist" December 1989:

In Search of Schrodinger’s Reindeer.

With the festive season upon us, many scientific minds will yet again be attempting to
solve that perennial chestnut, the Travelling Santa Problem (or TSP). This problem was
first brought to our attention by the child prodigy, Vernon P. Templeman, in his seminal
paper "Please may I have a bike for Christmas, Daddy" (J. Appl. Window Shopping,
December 1988, vol 7, p 1-122).

In simple terms, the problem boils down to one of speed. How can Father Christmas visit
the homes of all the children in the world in a single night, albeit 24 hours long?
Templeman demonstrated that the classical (sequential) explanation forces us to invoke
faster-than-light travel, which is somewhat at odds with current thinking.

Thus, he argued, we should infer that the Father Christmas effect does not really
exist. This contentious hypothesis was the subject of much debate at a recent symposium
held at the Santa Fe Institute for Present Research.

Our initial thoughts were that Templeman had over-estimated the size of the problem,
forgetting that Santa only visits good children. This would reduce the number of visits by
a factor of order 10^9.

However, a simple back-of-the-lab-coat calculation shows that this renders the problem
no more tractable. This threw suspicion on the use of classical physics. At this stage,
the teachings of our old mentor, Erwin Schroedinger, came back to us ("Famous people
what we claim to have known, honest", by Matthew Davies and Martin Slaughter, Annals
of Physics, 1983, vol 12, pp 379-381). From a detailed study of reported phenomena, it
became apparent that Santa shared many of the characteristics of elementary particles,
suggesting a quantum mechanical interpretation of his behaviour. We have since developed
this theory, and are confident that a quantum mechanical model of Santa Claus allows many
of his observed properties to be explained, and several interesting predictions to be
made.

Clearly, viewing Santa as a waveform removes the apparent paradox of his
"presence" being measured in several locations within a short interval of time.
As the waveform collapses down in a specific location (attracted, we suggest, by the
Goodness Quantum number of the recumbent child) it becomes perfectly valid to state that a
"visitation" has occurred.

However, our calculations suggest that the process of measurement (for example, turning
on the bedroom light) will almost certainly lead to a localised, space-time instability
which, in turn, will cause the waveform to relax and render detection almost impossible.

Once again, this ties in with the experimental evidence that Father Christmas is rarely
caught delivering. Indeed, on those few occasions when a sighting has been claimed in the
literature ("Mummy, mummy, there’s a strange man in my bedroom" by S. T. U.
Peedo, Journal of Sleepless Nights, 1979, vol 5, p 35), closer scrutiny has often revealed
it to be an imposter wearing a red cloak and beard.

Moreover, the quantum mechanical model predicts that energies involved in a waveform
collapse will result in the emission of a jet of sub-atomic particles. Studies of bedroom
carpets in the vicinity of alleged sightings, using an X-mass spectrometer, have often
revealed evidence of mince pion activity; though these have usually been Hoovered up.

One of the most appealing aspects of our theory is the manner in which it allows the
most likely sites for visitation to be estimated. These may be identified from the first
derivative of the expectation value as:

d (Spot) |

—————–|

d (Fireplace) | night

It turns out that the distribution of household chimneys is exactly that required to
act as a diffraction grating for objects of Santa’s predicted wavelengths, focusing
the zeroth order onto the bedroom floor below ("Chimchimmeny, chimchinny, chimchin
cheroo", by Bert, Mar. Popp. 1969).