From reindeer physiology and an aerodynamic sleigh carry Old St. Nick smoothly, silently and swiftly on Christmas Eve.
It used to be that people took it on faith that Santa Claus and his reindeer could fly. Long before we became the skeptics we are today, no one really cared how the big guy accomplished his seemingly impossible trek through the atmosphere every Christmas Eve.
But, alas, times have changed. Now people need to know exactly how – or even if – Santa does it each year. And the only way to keep them quiet is to demonstrate through reason, logic and pure, hard science that maybe, just maybe, old St. Nick can actually get in the air with his sleigh and reindeer. Fortunately, we can do that. For when you look at what Santa purports to do each year, it seems that he has harnessed some basic rules of physics, aerodynamics, reindeer biology (and, OK, maybe just a little magic) to get himself off the ground.
It all has to start with the sleigh. While most contemporary artists draw Santa’s sleigh as the classic 19th century wooden carriage, that can’t be accurate. It just doesn’t fly, you might say.
In order to get airborne, the sleigh must be constructed of super-thin aluminum alloys that cut down on weight (and when Santa’s inside, reducing weight is very important) and make flight easier.
“Those things are made light,” Dr. Haim Goldberg, a physics professor at Northeastern University who is familiar with airplane technology, said of most flying machines. “You are sitting up there in something which, for its size, is exceedingly light.”
Good start, Santa. But a sleek, light frame alone isn’t quite enough. Simple physics suggests that the esteemed Mr. Kringle also needs some wings on his sleigh if he wants to visit all the children of the world quickly.
“The reason you need wings is because you have to develop some lift,” explained Dr. Barry Holstein, a physics professor at the University of Massachusetts at Amherst. “Lift means there is more pressure under the wings than over the wings. That’s how an airplane flies.”
And that must be how Santa does it, too. To make sure the wind beneath his wings exerts more pressure than the wind above them, Santa has to design the wings the same way as the folks at the Boeing Co. – curved on top and flat on the bottom. That design increases the air speed above the wings, which is vital since, as Holstein explains, faster air speed results in lower air pressure and contributes to that much-desired lift.
That’s called Bernoulli’s Theorem and was discovered by 16th century Swiss mathematician Daniel Bernoulli. But let’s just say someone else a little further to the north might have known about it centuries earlier.
With the properly designed sleigh underneath his jelly belly and bag of toys, Santa then has to generate enough speed to get the lift needed to take off. Airplanes do it with powerful engines. But engines, of course, are very loud and might wake the children of the world as Santa makes his rounds.
That’s where the reindeer come in. Those animals are hearty enough to survive conditions at the North Pole but quiet enough so as not to disturb his young customers as the big guy flies over their homes and lands on their rooftops.
More important, reindeer can run fast – by animal standards, at least – about 35 mph. That’s a lot slower than the 150 mph threshold when most jumbo jets take off but, of course, the reindeer have something else helping them out – their antlers.
Those appendages, usually used to “lock horns” with reindeer rivals during mating season, can also serve as wings that are independent of the wings on the sleigh. With the air rushing underneath those antlers at a higher pressure than the air above, the nine reindeer can generate some lift of their own and maybe even get airborne at lower speeds than otherwise needed.
“They’re aerodynamic, and help provide some lift as well,” said Todd Fuller, an associate professor of wildlife at U-Mass.
Once in the air, some other parts of the reindeer’s anatomy can help Santa stay up without crashing or destroying all those toys. (And this is where some of that Christmas magic comes in).
For anything to remain in flight, it must have a force propelling it that can overcome the air resistance and drag it faces in the Earth’s atmosphere. Airplanes have their engines, be they jet or propeller, to accomplish that task.
Santa had better rely on Rudolph and the gang.
On the ground, the reindeer generate the force needed to move forward by stomping their extra-wide hooves on the ground as they run. Normally, that force only sticks around for as long as there is something – like the ground – to react to the force of the reindeer’s kicking.
In other words, flailing around in mid-air once they are flying should do little to help the reindeer continue moving forward.
But this is Christmas and the reindeer do have extra-wide hooves so, once in the air, maybe, just maybe, that can help keep them airborne, some scientists say.
“They have relatively wide hooves and when they run in the snow it’s supporting them better,” Fuller explained, without a trace of eggnog in his system. “So maybe it’s good for kicking air. Paddling through the air, that’s what I’m thinking.”
Fuller’s also thinking that the reindeer’s hollow hair – which helps insulate their bodies in winter time – might allow the wind to blow right through the animals’ fur without creating that dreaded drag.
As Santa lands on the rooftops to deliver toys to the children of the world, he must maneuver the sleigh carefully so the wings don’t clip the tops of the chimneys he needs to jump through. But, once again, his reindeer’s hooves provide the traction needed to land quietly, quickly and safely.
Despite such scientific explanations, the skeptics of the nation may still doubt that Kris Kringle can fly.
For further proof, maybe they should look to the Federal Aviation Administration. Each Christmas Eve, the no-nonsense FAA issues a special tail number for Santa’s sleigh, which allows him to operate below the 1,000-foot minimum flight level and restricts flights over the North Pole.
And perhaps those skeptics should allow themselves to rediscover the mind-set of that earlier period when everyone just believed that Santa and his reindeer could fly. Back then, they could hear the proof in Old St. Nick’s farewell greeting as he left their chimneys each year.
“I heard him exclaim as he drove out of sight, Merry Christmas to all and to all a goodflight?”
For more information on Santa’s flight, go to www.noradsanta.org.
Editor’s note: This story is reprinted from December 1998 (with minor alterations) as a holiday tradition.
The Patriot Ledger