The science of Christmas includes an examination of reindeer and their flying speeds

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The jolly gentleman pictured here has been and gone. But at what speed?

The question was addressed by Tom Chivers in an article in The Telegraph just before Christmas.

Santa Claus delivers presents to all the good children in the world. But how? And why? We take a look at the science of Christmas gifts

The first question tackled is: how fast does Santa travel?

The answer involves reindeer and their ability to travel enormous distances at high speed, which – at a stretch – makes this a matter of interest to agri-scientist readers.

Chivers says:

If we assume that Santa has to travel 510,000,000km on Christmas Eve, and that he has 32 hours to do it (the reasoning behind these numbers is another story), then Santa will be travelling at 10,703,437.5km/hr, or about 1,800 miles per second, all night (assuming he never stops: some sort of sleigh-mounted present-launcher will be required to shoot gifts down chimneys while moving.

The guidance system will have to be quite impressive, to avoid accidentally showering Afghan wedding parties with extra presents). It will probably also be advisable to have Santa catheterised to obviate the need for lavatory breaks.

How much will his sleigh weigh?

Last year, we calculated Santa’s sleigh (carrying 700,000,000 Optimus Primes and dragged by three million reindeer) to weigh 1,232,300 metric tonnes. However, this year, thanks to the success of Toy Story 3, he will have to be carrying Buzz Lightyears, which have a boxed weight of 1.2kg compared to Optimus’s comparatively puny 659g.

So that’s 840,000 tonnes of toys, which will require 5,600,000 reindeer to pull. Given each reindeer weighs around 272kg (600lb), the whole procession (assuming a weightless sleigh) will have a mass of 2,363,200 tonnes when standing still. Last year, however, we failed to take into account the relativistic increase in mass caused by the speed of the sleigh.

Travelling at 10,703,437.5km/hr, or 0.97 per cent of light speed, the whole thing will have an apparent weight to a stationary observer of 2,363,310.33 tonnes.

Can reindeer fly?

This was left to the Telegraph’s former science editor, Dr Roger Highfield, who has written an entire book of that name (Can Reindeer Fly?: The Science of Christmas.)

“Somewhere in the North Pole, or perhaps buried in a vast complex under Gemiler, there must be an army of scientists experimenting with the latest in high-temperature materials, genetic computing technologies and warped spacetime geometries, all united by a single purpose: making millions of children happy each and every Christmas”, he says. He takes a look at a few of the possibilities.

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.

Readers are invited to check out Can Reindeer Fly?: The Science of Christmas, by Dr Roger Highfield, for more information.

Why do we give gifts at all?

We’re all evolved, right? Selfish genes and all that. So how come we’re generous? How come we waste valuable resources on other humans when we could be keeping them all for ourselves? Yet altruism, and gift-giving, exists in thousands of animal species.

In most other species, it’s readily explicable by kin selection (being generous to close relatives who will likely carry our genes) or by reciprocity: males give gifts to females to boost their chance of mating; social creatures are generous to each other to gain favours themselves in future.

But humans are often generous to total strangers, almost certainly unrelated to them and who they may never meet again. Usually it’s explained by saying that it’s an evolutionary hangover from our days of living in far smaller groups.

But Professor Martin Nowak of Harvard University suggests that our generosity is still evolutionarily helpful, because it creates a “network” of altruism that will eventually come back to benefit us: “I help you, and eventually somebody else will help me”.

“Our analysis shows that gratitude and other positive emotions, which increase the willingness to help others, can evolve in the competitive world of natural selection,” says Prof Nowak, leading to “an ‘epidemiology of altruism’ resulting in an explosive increase of altruistic acts.”

AgScience trusts at least some aspects of this post opens up research ideas for institute members.

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