Physics of Santa 2.0 - The Skeptical Teacher

A Santa Claus?

Walker (Spy Magazine) and

Joe Serpico @ Niles West

High School

No known species of reindeer can fly.

But there are some 300,000 species of living organisms yet to be classified, and while most of these are insects and germs, this does not

COMPLETELY rule out flying reindeer which only Santa has ever seen.

According to a well-reasoned article by The

Atlantic magazine in 2011, there are about 526 million children under the age of 14 that will be visited by Santa on Christmas Eve.

At an average of 3.5 children per household, that’s about 150 million households, assuming at least one good child in each house.

Santa has 31 hours of Christmas to work, thanks to the different time zones and the rotation of the earth, assuming he travels east to west, which seems logical. This works out to

1344.1visits per second.

This is to say that for each household he visits with a good child, Santa has ~ 1/1400 th of a second to park, hop out of the sleigh, jump down the chimney, fill the stockings, distribute the remaining presents under the tree, eat whatever snacks were left out, get back up the chimney, back into the sleigh and move to the next house.

- Assuming each of these 150 million houses is evenly distributed (which is false, but will be assumed for calculation’s sake) over the land masses of the planet, we are now talking about

1.02 kilometers per household and a total trip of

150 million kilometers, not counting stops for feeding his team of deer, his overweight self, and to do what most of us must do at least once in 31 hours.

Hey! That better not be a Mr. Hankey reference!

This means that Santa’s sleigh would be moving at ~1350 km per second, which is 3800 times faster than the speed of sound!!!

This will create deafening sonic booms (so much for

Silent Night

) in Santa’s wake!

Also, for comparison, the fastest human-made vehicle

(moving relative to Earth) is the New Horizons space probe bound for Pluto, which moves at 16.3 km/sec.

Conventional reindeer can run at about 24 kilometers per

HOUR… tops!

The payload on the sleigh adds an interesting element to the whole idea. Assuming that each child gets nothing more than a medium-sized

Lego set (0.908 kg), the sleigh is carrying

477,610,000 kg (or

477,610 metric tons), not counting

Santa, who is invariably described as overweight.

On land, conventional reindeer can pull no more than about 136.2 kg effectively. Even granting that “flying reindeer” exist and could pull ten times the normal load, we cannot do the job with eight, or even nine of them. In fact, we need

350,670 reindeer on the team!

Also, assuming an average reindeer mass of

170 kg, this increases the payload

– not even counting the mass of the sleigh itself

– to

537,220 metric tons!

This is over six times the mass of Queen Elizabeth

(the ship, not the woman).

537,220 metric tons traveling at 1,344 km/sec would create enormous air drag, and friction with the air would heat up the sleigh just as spacecraft do upon reentering the Earth’s atmosphere. The entire reindeer team, sleigh, and Santa would absorb over

5.08x10

18

Joules of heat every second!!!

For comparison, the largest nuclear weapon ever detonated

– the Tsar Bomba – yielded about

2.10x10

17

Joules worth of energy. So in our calculation, Santa’s sleigh would have to absorb over twenty times the total energy output of the largest nuclear bomb ever detonated every second! In short, Santa and his entire reindeer team will be vaporized within the blink of an eye! KABOOM!!!

Even if Santa were to have the mother of all heat shields to absorb and dissipate this astronomical amount of energy, he would be subjected to

ENORMOUS g-forces from his sudden accelerations, amounting to ~192

MILLION times the force of gravity! In other words, if

Santa wasn’t immediately vaporized, he and his entire reindeer team would be squashed into jelly!!!

In conclusion -- If Santa ever DID deliver presents on Christmas Eve, he’s dead now.

HAPPY HOLIDAYS!!!