Santa Claus - The Scientific Explanation
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. For the sake of our ensuing calculations, we will assume that there is 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 1.2 milliseconds 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 71.6 million miles, not counting stops to do what most of us must do at least once every 31 hours.
This means that Santa's sleigh is moving at appx 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 mere 27.4 miles per second - a conventional reindeer can run 15 miles per hour, unless being chased by a pack of wolves.
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 (the boat, not the person).
5. 353,000 tons travelling at 650 miles per second creates enormous air resistance - thus heating the chain in almost the same fashion as spacecraft re - -entering the earth's atmosphere. As a result of this friction, the lead pair of reindeer will absorb around 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 vaporised within 4.26 milliseconds. Santa, meanwhile, will be subjected to centrifugal forces 17,500 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.
Santa was very cross. It was Christmas Eve and NOTHING was going right. Mrs. Claus had burned all the cookies. The elves were complaining about not getting paid for the overtime they had while making the toys. The reindeer had been drinking all afternoon and were dead drunk. To make matters worse, they had taken the sleigh out for a spin earlier in the day and had crashed it into a tree.
Santa was furious. "I can't believe it! I've got to deliver millions of presents all over the world in just a few hours - all of my reindeer are drunk, the elves are on strike and I don't even have a Christmas tree! I sent that stupid Little Angel out HOURS ago to find a tree and he isn't even back yet! What am I going to do?"
Just then, the Little Angel opened the front door and stepped in from the snowy night, dragging a Christmas tree. He says "Yo, fat man! Where do you want me to stick the tree this year?"
And thus the tradition of angels atop the Christmas trees came to pass........