Santa maintains a huge list of children who have been good throughout the year. The list even includes addresses, ZIP codes and postal codes. The list, of course, gets bigger each year by virtue of the world’s increasing population. This year’s population right now is 6,634,570,959!
Santa has had to adapt over the years to having less and less time to deliver his toys. If one were to assume he works in the realm of standard time, as we know it, clearly he would have perhaps two to three ten-thousandths of a second to deliver his toys to each child’s home he visits!
The fact that Santa Claus is more than 15 centuries old and does not appear to age is our biggest clue that he does not work within time, as we know it. His Christmas Eve trip may seem to take around 24 hours, but to Santa it could be that it lasts days, weeks or months in standard time. Santa would not want to rush the important job of bringing Christmas happiness to a child, so the only logical conclusion is that Santa somehow functions on a different time and space continuum.
Official Google Blog: Tracking Santa, then and now