The science of Christmas

At this time of year, one of the most-asked questions scientists get is this: how does Santa deliver presents to all the children around the world in just one night? Does Santa’s sleigh have an anti-matter rocket that propels it around the planet at close to the speed of light? Or is it equipped with the ability to warp space and time? Or does Santa just make use of stocking-to-stocking wormholes instead?

I’m far more interested in Santa’s helpers, the reindeer. I was fascinated to learn that Dasher, Dancer, Prancer, Vixen, Comet, Cupid, Donner, Blitzen, and Rudolph are female. Each year, male reindeer shed their antlers at the end of the mating season in early December, while the females keep theirs throughout the festive season.

But the science I’m most interested in is how Rudolph (or should that be Ruby?!) gets her glowing nose. The red-nosed reindeer are rare, so we scientists can only hazard a guess as to how they make light based on what we know about other glowing creatures. I have a few pet theories.

You might have had the chance to see

New Zealand’s renowned glowworm caves at Waitomo? Our famous maggots are bioluminescent, creating their light by mixing proteins called luciferins and luciferases together in the presence of oxygen. It’s possible that rednosed reindeer glow in a similar way.

Or their noses could be fluorescent, full of special proteins, which absorb electromagnetic radiation, exciting their electrons, and producing red light when those excited electrons return back to their stable state.

But my favourite theory has to be that the rednosed reindeer live in symbiosis with trillions of bioluminescent bacteria that glow brightly in return for nutrients and a place to call home. While the Hawaiian bobtail squid uses its symbiotic glowing bacteria as an invisibility cloak, and the deep-sea anglerfish uses its to lure its next meal, Rudolph/Ruby uses her bacteria to guide Santa’s sleigh.

Meri Kirihimete everyone!

Microbiologist and bioluminescence-enthusiast Dr Siouxsie Wiles is an Associate Professor at the University of Auckland.

Does Santa’s sleigh have an antimatter rocket that propels it around the planet at close to the speed of light?