Neil deGrasse Tyson Answers Elon Musk's Top Interview Question

You might think you're clever, but could you answer the brainteaser interview question that Elon Musk has used to screen potential employees? Renowned astrophysicist Neil deGrasse Tyson can.

According to a 2015 biography by Ashlee Vance, many of SpaceX's early employees were personally interviewed by Musk and likely answered his favorite riddle:

"You're standing on the surface of the Earth. You walk one mile south, one mile west and one mile north. You end up exactly where you started. Where are you?"

We then brought the brainteaser to Tyson.

The astrophysicist, of course, gave us the correct answer: The North Pole. Starting there, if you walk one mile south, one mile west and one mile north, you'll make a triangular path and end up back at the North Pole, your point of origin.

Most SpaceX engineers also give the North Pole version of this answer. However, there are many other ways to approach this brainteaser.

Another answer that Musk reportedly accepts has a person starting near the South Pole and walking a mile to where the earth has a one mile circumference. One can then trace that circle's path and return one mile north to the starting point.

In fact, "there are actually an infinite number of such points," said Rachel Rosen, an assistant professor of theoretical physics at Columbia University.

While Tyson wasn't baffled by Musk's brainteaser in the least, he admitted that those who aren't familiar with the geometry of a non-flat world, also known as non-Euclidean geometry, would likely be perplexed.

"There is a sphere of knowledge for which that question is trivial," explained Tyson. "If you do not have that sphere of knowledge, then it's an intriguing problem … and you should ask it."

Musk, Vance wrote, is less concerned with the actual answer than how potential candidates tackle it. Musk reportedly interviewed a range of employees in SpaceX's early days, including engineers, technicians and janitors.

Wrote Vance, Musk "tends to care less about whether the person gets the answer than about how they approach the problem."

Tyson added jokingly, "Santa clearly knows [the answer] ... Have you interviewed Santa?"

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Neil deGrasse Tyson answers Elon Musk's brainteaser interview question | CNBC Make It.

[earthwizz]

I was about 12 when I first came across this brainteaser, 60 years ago. It was fairly simple then.

[brokehalo]

Can someone dumb this down for me. I'm slow

[jamesmyers]

The funny thing is about this question, is that everyone is over thinking it. It doesn’t matter where you start. You can go as far as you want, in any direction, and you will end up exactly where you you started... Earth 🌍

[lewisner]

"Is there a word less than trivial ?"
Yes, Trivia.

Elon Musk asks this to see if the interviewee will get BOTH the answers. The one Neil gives is obvious. The second one is:

1. Start 1 mile north of the circle with circumference of one mile around the south pole
2. Walk south 1 mile until you're at this circle
3. Walk around the circle
4. Walk 1 mile north, and you're back where you started.

[jacksonaguilar]

Elon Musk: Why did the chicken cross the road?
Fanboys: (grabs calculator, looks up earnings reports, studies Poultry and Civil Engineering)

Also Fanboys be like: Is it a road on Earth or Mars? How many lanes does the road have? Is it a hen or rooster? (while brain cells silently exploding inside their heads trying to comprehend the genius of the formulas and equations it might need to answer the question.

Normal People ANSWER: To get to the other side!

Fanboys: That's what they want you to believe!

[martinstephens]

@NDG -

Just so you know, the boring answer is indeed "the north pole".
There are, in fact, an infinity of solutions.
I know when you read this you may think "he may not understand the problem", so I'll give you one of the other infinities.

Go to a place relatively close to the south pole, such that, when you walk the mile south, your now on a circle of longitude which is 1 mile in circumference.
So, when you walk east, you actually "circumnavigate the globe", head north and you're back where you started.

Clearly there are infinitely many points you can have chosen to start from.

More to the point, this isn't the only infinity of points, there are infinitely many others - am I sure you can come up with the set of all points.

Best wishes,
M

[BullCheatFR]

Second answer is any point 1+1/pi miles from the south pole. :)

[zackcarl]

This is an old question, not something Elon made my grandpa actually answered it because he has already came across with this question while he was in college

[maytals]

The correct answer is the doctor was his mother!

[jimnichols]

Elon's question is to gather geniuses. Step 2 is to breed the geniuses. But this has already been tried by the NSDAP.

[FernandoPerez-zxvz]

So it's not a question to spot a genius but someone who studied Euclidean Geometry huh 😞

[freefallingearth]

The easiest interview question I've ever had or heard. Not challenging what so ever.