CHRISTMAS PHYSICS
There are approximately 2 billion children (persons under 18) in the world. Santa doesn't (appear) to handle children of families who hold to faiths other than Christianity including, but not limited to, Muslim, Hindu, Jewish and Buddhist children. This reduces the overall workload to 15% of the total - 378 million according to Population Reference Bureau as of the date of this analysis. At an average census rate of 3.5 children per household, that calculates to 91.8 million homes. We will presume one Good child per household. The Naughty/Nice child ratio was not validated for this analysis.
Assuming Santa travels east to west (the most logical choice), and calculating for planetary rotation and different time zones, Santa has 31 full hours in which to finish his Christmasly duties. This works out to 822.6 visits per second. To clarify, this means 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), this calculated to approximately .78 miles per household for a total trip of 75-1/2 million miles, not counting stops to feed and rest the reindeer, eat, and do what most of us must do at least once every 31 hours. This means Santa's sleigh is moving at a brisk 650 miles per second - approximately 3000 times the speed of sound at sea level. For further reference, that speed (2.34 million miles per hour in more everyday parlance) is 126.5 times faster than the orbital velocity of the Space Shuttle. For comparison, the fastest man-made vehicle ever constructed, the Ulysses space probe, moves at a poky 27.4 miles per second - a conventional reindeer can run approximately 15 miles per hour. Tops.
The payload on the sleigh adds another interesting element. ssuming each child gets nothing more than a medium-sized Lego set (2 pounds), the sleigh is carrying 321,300 tons, not counting Santa. 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 cruise liner Queen Elizabeth and twice the weight of a fully laden modern supertanker. 353,000 tons traveling at 650 miles per second creates enormous air resistance, heating the reindeer in the same fashion as a spacecraft reentering the earth's atmosphere. The lead pair of reindeer will absorb 14.3 QUINTILLION joules of energy. Per second. Each. In short, it is no wonder that Rudolph's nose glows!! 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 - enough force to cause steel to flow like a viscous liquid.
Presuming that proven scientific facts are incontrovertable and that simple physics dictates the above conditions, we must conclude that, if there ever really was a Santa, hes dead now.