It was Christmas Eve, a fine crisp night, and I had just poured myself a large brandy, stoked the fire and settled into the leather chair with my copy of Dickens 'Christmas Carol', when Virginia, my eight year old daughter, opened the door into my study.
"Daddy", she said, rubbing her eyes with one hand while fiercely clutching a teddy bear with the other, "Will Santa still come tonight?". Pausing to place the drink on the leather topped bureau, I held my arms open to her and then placed her on my knee and looked into her little blue eyes. I am not an unsentimental man, though some claim that I do not suffer fools gladly, but I had always resolved to be forthright and truthful with my offspring and answer all questions in the only way I knew how. The Scientist and philosopher in me demanded nothing else. So it was not without a heavy heart that I adjusted my pince-nez and held my darling daughters little hand. "Now, Virginia, you must listen carefully to what I have to say. There are several points you must heed, for me to answer that question....."
"Point 1, my sweet. 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."
"Secondly, 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 at least reduces the workload to 15% of the total - 378 million according to the Population Reference Bureau. At an average rate of 3.5 children per household, that's 91.8 million homes. One presumes there's at least one good child in each" (although readers with children may feel that this stretching the figures somewhat!)
"Point 3. Santa has 31 hours of Christmas to work with, thanks to the different time zones and the rotation of the earth, so, to avoid argument, assuming that he travels from east to west, 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 up the stockings, distribute the remaining presents under the tree, eat whatever snacks have been left, get back up the chimney, 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 75.5 million miles, not counting stops to do what most of us must do at least once every 31 hours, plus feeding and chatting to the reindeer. 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 lowly 27.4 miles per second - a conventional reindeer can run at approximately 15mph."
"The payload on the sleigh adds another interesting point, my darling. Assuming that each child gets nothing more than a medium-sized lego set, about 2 pounds in weight, 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, this amount of reindeer 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."
"Finally, my angel. 353,000 tons travelling 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 vaporised 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."
My sweetest treasure looked at me with a glisten in her eye. "Oh Daddy, you mean.....?" "Yes, my darling", I replied grimly "If Santa ever did exist he must certainly be dead now!"
Well, I won't pretend that Christmas Day went well. Virginia did not seem her usual joyful self and I did not relish the sight of next door's cat eating my Christmas dinner. The throbbing from the swelling on my head where my wife broke the bottle of vintage claret subsided somewhat with the alternate distraction of seeing my favourite pipe being chewed by the dog.
Nevertheless, I feel the clarity of science will serve my daughter well in her future years - although I may need to obtain a court order to enable me to see it. However, one thing I can say for certain, I will not forget the Christmas Eve when I said "No, Virginia, there is no Santa Claus".