THE ORIGINAL "SANTA PHYSICS" PROPOSAL:
1) No known species of reindeer can fly. BUT there are 300,000 species of living organisms yet to be classified, and while most of these are insects and germs, this does not COMPLETELY rule out flying reindeer which only Santa has ever seen.
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 total - 378 million according to 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 1/1000th 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 .78 miles per household, a total trip of 75-1/2 million miles, not counting stops to do what most of us must do at least once every 31 hours, plus feeding and etc.
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 man-made vehicle on earth, the Ulysses space probe, moves at a poky 27.4 miles per second - a conventional reindeer can run, tops, 15 miles per hour.
4) The payload on the sleigh adds another interesting element. Assuming that each child gets nothing more than a medium-sized 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 granting that "flying reindeer" (see point #1) could pull TEN TIMES the normal amount, we cannot do the job with eight, or even nine. We need 214,200 reindeer. This increases the payload - not even counting the weight of the sleigh - to 353,430 tons. Again, for comparison - this is four times the weight of the Queen Elizabeth.
5) 353,000 tons traveling at 650 miles per second creates enormous air resistance - this will heat the reindeer up in the same fashion as spacecraft re-entering the earth's atmosphere. The lead pair of reindeer will absorb 14.3 QUINTILLION joules of energy. Per second. Each. In short, they will burst into flame 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 17,500.06 times greater than gravity. A 250-pound Santa (which seems ludicrously slim) would be pinned to the back of his sleigh by 4,315,015 pounds of force.
In conclusion - If Santa ever DID deliver presents on Christmas Eve, he's dead now.
Rebuttal: Several key points are overlooked by this callous, amateurish "study."
1) Flying reindeer
First, as admitted, it is possible that a flying reindeer can be found. I would agree that it would be quite an unusual find, but they might exist.
Second, as is widely known (due to the excellent historical documentary "Santa Claus is Coming to Town," the flying reindeer are not a previously unknown species of reindeer, but were in fact given the power of flight due to eating magic acorns. As is conclusively proven in "Rudolph the Red-Nosed Reindeer" (a no punches pulled look at life in Santa's village), this ability has bred true in subsequent generations of reindeer - obviously the magic acorns imprinted their power on a dominant gene sequence within the reindeer DNA strand.
2) Number of households
This figure overlooks several key facts. First of all, the first major schism in the Church split the Eastern Churches, centered in Byzantium, from the Western, which remained centered in Rome. This occurred prior to the Gregorian correction to the Julian calendar. The Eastern churches (currently called Orthodox Churches) do not recognize the Gregorian correction for liturgical events, and their Christmas is as a result several days after the Western Churches. So Santa gets two shots at delivering toys.
Secondly, the figure of 3.5 children per household is based on the gross demographic average, which includes households with no children at all. The number of children per household, when figured as an average for households with children, would therefore have to be adjusted upward. Also, the largest single Christian denomination is Roman Catholic, who, as we all know, breed like rabbits. Due to the predominance of Catholics within Christian households, the total number of households containing Christian children would have to be adjusted downward to reflect the overloading of Catholics beyond a standard deviation from the median.
Third, the assertion that each home would contain at least one good child would be reasonable enough if there were in fact an even 3.5 children per household. However, since the number of children per household is distributed integrally, there are a significant number (on the order of several million) of one child Christian households. Even though only children are notoriously spoiled and therefore disproportionately inclined towards being naughty, since it's the holidays we'll be generous and give them a fifty-fifty chance of being nice. This removes one half of the single child households from Santa's delivery schedule, which has already been reduced by the removal of the Orthodox households from the first delivery run. Alternately, what if anti-selection applies, and homes with good kids tend to have more than their share of good kids, and other homes have nothing except terrorists in diapers? Let's drop that number of homes down a few more percent.
Fourth, this analysis has relied on a uniform distribution of children across homes. Toronto/Yorkville, or Toronto/Cabbagetown, or other yuppie neighbourhoods, have probably less than the average (and don't forget the DINK and SINK homes (Double Income No Kids, Single Income No Kids)), while the families with 748 starving children that they keep showing on Vision TV while trying to pick our pockets would skew that 15% of homes down a few percent.
Fifth, Santa would have to Fedex a number of packages ahead of time, since he would not be able to fly into Air Force Bases, or into tower-controlled areas near airports. He's get shot at over certain sections of the Middle East, and the no-fly zones in Iraq, so he'd probably use DHL there. Subtract some more homes.
So the number of homes Santa needs to visit is substantially reduced from the initial estimate.
3) Santa's delivery run
These all suffer from the dubious supposition that there is only one Santa Claus. The name "Santa" is obviously either Spanish or Italian, two ethnic groups which are both overwhelmingly Catholic. The last name Claus suggests a joint German/Italian background. His beginnings, battling the Burgermeister Meisterburger, suggest he grew up in Bavaria (also predominantly Catholic). The Kaiser style helmets of the Burgermeister's guards, coupled with the relative isolation of the village, suggest that his youth was at the very beginning of Prussian influence in Germany. Thus, Santa and Mrs. Claus have been together for well over one hundred years. If you think that after a hundred years of living at the North Pole with nights six months long that they remain childless, you are insane. There have therefore been over five generations of Clauses, breeding for over one hundred years. Since they are Catholic, their exponential population increase would obviously have a gain higher than the world population as a whole. There have therefore been more than enough new Santas to overcome the population increase of the world. So in fact, Santa has an easier time of it now than he did when he first started out.
As to speed, Einsteinian Theory that says time does strange things as you move faster. In fact, when you go faster than the speed of light time runs backward, if you do a straight line projection, connect the dots and just ignore any singularity you might find right at the speed of light. So Santa could go faster than light, visit all the good children which are not uniformly distributed by either concentration in each home or by number of children per household, and get home before he left so he can digest all those stale cookies and warm milk.
But Santa only has reindeer, so where does he get the power to move that fast? You calculated the answer! The lead pair of reindeer will absorb 14.3 QUINTILLION joules of energy. Per second. Each. This is an ample supply of energy for the maneuvering, acceleration, etc, that would be required of the loaded sleigh. The reindeer don't evaporate or incinerate because of this energy, they accelerate. What do you think they have antlers for, fighting over females? Think of antlers as furry solar array panels.
Santa dead, indeed - some people will twist any statistic to "prove" their cynical theory.