Submitted by Mark White
 
 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 1) 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 Liner "Queen Elizabeth 2".
 
 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.
 
 This inquiry is based on the premise that there is only one Santa
 Claus.
 
 The calculations work out more realistically if you assume some
 form of parallel processing. A thousand Santas (1 kilosanta) or a
 million (a megasanta) or more, working in parallel, could perform
 the same number of visits in the same allotted time with less
 advanced technology (and fewer vaporized reindeer).
 
 Who does the air traffic control for a megasanta? A million
 sleighs and 12 million reindeer occupy a significant amount of
 airspace.
 
 If we assume that each reindeer team, sleigh and Santa needs no
 more than 5 feet of vertical airspace (which, given that known
 species of reindeer with antlers are quite nearly five feet tall,
 leaves very little room for error), then a megasanta requires
 almost 947 miles of vertical airspace. This also disregards the
 fact that each Santa must make frequent landings.
 
 The airspace at chimney level will be in high demand and
 disproportionately crowded, particularly as Christmas-celebrating
 households tend to be densely clustered in the same geographic
 areas. It seems likely that a megasanta, while perhaps avoiding
 vaporized reindeer, would suffer huge casualties from mid-air
 collisions.
 
 So there you have it.  Be sure to tell the kids.