IT'S a question as old as Christmas itself. Many people have developed theories but only Santa and his elves know for sure.
I asked my eight-year-old. He said that Santa knows how to stretch time so that he has enough time to travel the world in one night. And when he stretches time, he moves very quickly relative to us and that is why people rarely see him and have never captured him on video. The eight-year-old is big into science and likes to understand how things work so he has asked a lot of questions about Santa over the years.
I asked my four-year-old and she said that the reindeer can go very, very fast. The two-year-old just said: "I don't know", which probably sums up most people's understanding of how it all works.
Santa has about 32 hours to deliver his presents. As countries directly to the east of the International Date Line are 24 hours behind those directly to the west of the line, if Santa started delivering presents at 10pm on Tonga, travelled west and finished at 6am in the Samoa Islands, that would give him a full 32 hours. But, with about 2.2 billion children in the world, that is still a pretty tall order. So how does he do it?
Dr Larry Silverberg, professor of mechanical and aerospace engineering at North Carolina State University, says that Santa's know-ledge of the space-time continuum, nanotechnology and computer science helps him to complete his task.
Dr Silverberg was head of the first team of scientists ever to visit Santa at his North Pole workshop when he travelled there two years ago. He explains that Santa uses this knowledge of the space-time continuum to form "relativity clouds".
"Based on his advanced knowledge of the theory of relativity, Santa recognises that time can be stretched like a rubber band, space can be squeezed like an orange and light can be bent," Dr Silverberg says.
"Relativity clouds are controllable domains -- rips in time -- that allow him months to deliver presents while only a few minutes pass on Earth. The presents are truly delivered in a wink of an eye."
According to Danny Maruyama, a systems physics researcher at the University of Michigan, Dr Silverberg's theory is plausible.
"While I don't know much about relativity clouds myself, I think it's very possible that a man who flies in a sleigh, lives with elves and has flying pet reindeer could have the technology needed to utilise relativity clouds," he says. Ok, but what about all those toys?
Dr Silverberg reckons that Santa doesn't actually carry all the toys in his sleigh, but that he has a 'magic sack', a sort of nano-toymaker that uses a reverse thermodynamic processor to create toys inside the children's homes.
The presents would then be grown on the spot, atom by atom, much like DNA can command the growth of organic material like tissues and body parts. And there's no real need for Santa to enter the home via a chimney, although Dr Silverberg says he enjoys doing that every so often.
Instead, the same relativity cloud that allows Santa to deliver presents can also be used to "morph" Santa into children's homes. One thing we do know for sure is that Santa is helped on his way by NORAD, a joint United States and Canadian organisation that monitors and controls the aerospace in that region.
NORAD uses its ground-based radars and satellites to help Santa take advantage of carefully timed gravity assists from the Sun, Moon and Earth, which help him travel faster and navigate much more precisely.
NORAD also uses satellites to track weather conditions on Santa's route to aid navigation. Rudolph provides a good infrared source on which the satellite instruments can focus -- his bright red nose can be detected with great precision.
Huge improvements in weather prediction models are also credited with helping Santa determine the most efficient route.
"Numerical weather prediction has certainly vastly improved in the past 20 years and even the past 10," says Joanna Donnelly, of Met Eireann.
"Santa is able to make much better use of the jet stream and the strong winds in the upper atmosphere to greatly speed his journeys between the continents."
So that is, as far as we can determine, how Santa makes it around the world in 32 hours. To those who just didn't think it was possible, I have just one thing to say: Believe.
You can follow Santa's progress around the globe on Christmas Eve at www.noradsanta.org.