Santa's on his way . . .

. . . and you can track his path, as always, at NORAD.

The Telegraph has published a couple of useful articles to explain how he does it.  The science behind Santa is handily explained.

A rocket-powered sleigh is out of the question: the fuel costs would be prohibitive (not that that has stopped people drawing up possibilities). But if Santa’s elves - “undoubtedly the most spectacular research and development outfit this planet has ever seen” - have worked a way of warping space-time, allowing the sleigh to sit in a small bubble of space that itself moves, it could travel faster than light. Alternatively, wormhole technology could provide cosmic short-cuts, and would have the benefit of permitting time-travel, removing the constraint of having to get all the work done in one night.

But this all involves a powered sleigh. The reindeer themselves still need to be able to fly. This could be achieved by genetic engineering, altering the reindeer so their lungs are huge and filled with helium; they could even be born with wings and stabiliser fins. Or, as Professor Ian Stewart, Warwick University maths professor and occasional Telegraph contributor, points out: “Reindeer have a curious arrangement of gadgetry on top of their heads which we call antlers and naively assume exist for the males to do battle and to win females. This is absolute nonsense. The antlers are actually fractal vortex-shedding devices. We are talking not aerodynamics here, but antlaerodynamics.” At the speeds the reindeer have to travel to deliver gifts, their antler-tips would, apparently, create enough lift to allow them to fly.

There's more at the link.

As for Christmas Eve in numbers:

Speed of sleigh

If he's clever about it, and travels from east to west with the Sun, maximising his available night-time, Santa has about 32 hours to work with (assuming children sleep for eight hours, he has 24 hours plus those eight to finish). Travelling 342,510,000km in 32 hours equates to a speed of 10,703,437.5km/hr (6,650,807.72mph), or a little under 1,800 miles per second, assuming he takes no time actually to deliver the presents or stop for any comfort breaks. The fastest-moving man-made object in history, the space probe Voyager 1, manages a rather less impressive 10.8 miles per second.

Weight of gifts carried

Assuming each child gets the Transformer Optimus Prime, the leader of the Autobots, for a present, in his box, Santa will be carting 659g (1.45lb) per child. That's 461,300 metric tonnes, or about the same in imperial tons, total. For comparison, a Boeing 747-8I airliner can carry 237.5 tonnes in passengers, luggage and fuel.

Again, more at the link.

Ah, well.  Science, mathematics or whatever - it's still Christmas Eve!

I said all I wanted to say about Christmas back in 2008, as regular readers will know.  I wish all of you the happiest, healthiest and most blessed Christmas it's possible for you to have.  May the blessings of this season of grace be yours, and may they go with us all into the new year that lies ahead.  Thanks for keeping company with me over the past year.

Peter