## Sunday, December 24, 2017

### "Can Santa Claus bend the space-time continuum?"

From The Verge:
Santa employs some fancy physics in his annual chimney-hopping marathon.
Okay, so here’s the thing about Santa Claus. Every year, this elderly, overweight man somehow manages to lug giant bags of toys down millions of chimneys. He does this in the span of a couple hours, without being spotted, and without toppling off icy roofs.

It’s an impressive — if suspicious — series of feats. And Claus does, after all, have a history of suspicious behavior, including a series of alleged hit-and-runs involving grandmas

So, how does he accomplish this annual chimney-hopping marathon? Claus could not be reached for comment. So instead, we quizzed two physics professors about Claus’s possible methods.

The main thing Claus needs is a serious source of energy, says Dave Custer, a physics and writing lecturer at MIT. From Custer’s back-of-the-envelope calculations, he estimates that Claus visits maybe a million households in the US in the span of approximately six hours. That means that each visit — including getting down the chimney, arranging presents, and getting back up again — can only take 0.0002 seconds.

If each of those households has a chimney that averages 16 feet in height, that means on Christmas Eve, Santa Claus climbs the equivalent of Mount Everest over 50,000 times. And if he weighs a healthy 175 pounds these days, then it would take the equivalent of a 24,000-horsepower engine, or the engines of more than 160 Ford F150 pickup trucks, to propel him that distance. That requires as much energy as MIT’s sustainable power plant produces, he says.

“That’s a pretty beefy power expenditure. I know magic is magic and everything, but last we checked energy needs to be conserved,” Custer says. At least, if Claus is abiding by the law of conservation of energy, which says energy is neither created nor destroyed — it just changes from one form to another.
So if Claus is powering his efforts with cookies, he’d need to consume a steady stream of them at each house he visits. Even then, he’s probably be in a caloric deficit. “How on earth does Santa manage to keep that paunch?” he wrote in an email. So cookies are probably insufficient fuel, but a power plant is too big to lug around and to fit through chimneys.

Custer’s not certain how Claus fits, or how he gets back up the chimney. “I can’t claim to have been in a lot of chimneys, but I’ve looked up a few, and they’re not handhold friendly,” Custer says. He thinks that the inside of a chimney is probably too smooth to scale, but if Claus were ascending back up his rope as fast as he needs to, he’d probably burn up the rope.

Larry Silverberg, a physics professor at North Carolina State University, suspects Claus manages this by altering the space-time continuum. “Basically what we’ve learned in relativity is two things: one is that that time can be stretched — that’s called time dilation. And space can be contracted,” Silverberg explains. Claus could be creating little pockets where he can control time and space, called relativity clouds. Inside the cloud, Claus can shrink himself to the size of a Christmas ornament, so he could easily fit down the chimney....MORE