What If You Drilled a Hole Through Earth?

This would be the journey of a lifetime, if you don’t mind riding through molten rock and crushing pressure. What would you see along the way? How long would this journey through Earth take?

And how would a gravity train keep you alive? The heat is on, and you’re under all sorts of pressure.

Imagine going from Argentina to China in less than an hour. All you need is a hole straight through the Earth. But drilling this hole would be the hardest part of this endeavor.

You could just handle it supervillain style and fire a giant laser at Earth. But today, we’ll be taking a trip through the biggest hole we’ve drilled in the history of our planet. Sit tight because this is going to be one hell of a ride.

The first thing you’d need to do would be to drill the deepest hole humanity has ever imagined. We’ve already drilled holes through the Earth on What If. So you know what to do. First, you’d need a really big drill. And it would take a few years to complete this project. You’d be working in enormous heat and pressure, and it would increase the closer you get to Earth’s center.

But when the hole is finished, you’d have your very own gravity tunnel, a gateway between one side of the Earth and the other. I’ll explain how it would work in a moment. Next, you’d need to find yourself a comfy vehicle to get you through the Earth.

If you just jumped into the depths of the Earth, you would get burned to a crisp and crushed into a pancake. So hop on the gravity train. This train would accelerate using only the force of gravity. And it would protect you from the searing heat and extreme pressure.

The first leg of the journey would take you through Earth’s crust. Depending on where you begin your trip, the crust can be 5 to 70 km (3 to 43 mi) thick. And amazingly, it only makes up 1% of the entire Earth.

You’d start your journey feeling pretty carefree. And at 20 m (67 ft) below the surface, you’d be at the same level as subways or the Paris Catacombs. But let’s go a bit further down. At 2.5 km (1.4 mi), you would be at the same depth as the deepest fossil ever discovered.

And once you get to 3.6 km (2.2 mi), you’d be able to see the devil worm. It’s the deepest living animal ever found. Is it just me, or is it getting hot? Believe it or not, some people are working at this depth. The Mponeng gold mine in South Africa is so far down that the heat is an issue. And believe me, you wouldn’t enjoy the 60 °C (140 °F) temperature down there.

Then gravity would take you further down. At 8.8 km (5.5 mi) below Earth’s surface, you’d have traveled further than the height of Mount Everest. And at 11 km (36,037 ft) underground, you’d be deeper than the Mariana Trench is.

At 12.26 km (7.61 mi), you would reach the same depth as that Kola Superdeep Borehole. It’s the deepest hole we’ve ever dug. And you’d really feel the intense pressure on your body.

At this depth, air pressure is 4,000 times the pressure at sea level. As you approach the end of the first part of this epic journey, you might get to see a plethora of gems. I’m talking about rubies, sapphires and emeralds. They could be valuable souvenirs if you make it through to the other side of Earth.

And at 40 km (25 mi) down, part one of your voyage would be behind you. Or above you, depending on how you see it. Let’s go onward to the second layer of Earth, its mantle.

Most people think it has a lava-like texture. But at this shallow depth, relatively speaking, it’s rock solid. Only when you’re deeper will it start becoming molten. This would be the longest part of your journey. That’s because the mantle makes up an impressive 84% of Earth’s volume.

The mantle is about 2,900 km (1,801 mi) thick. You wouldn’t see much inside it, except for one dazzling exception. At this depth, the enormous pressure and heat form diamonds. They make their way to the Earth’s surface through volcanic activity. And that’s where we humans find them. But you are lucky and find them at their birthplace. Don’t be shy. Grab a few.

As you arrive about 410 km (255 mi) below the surface, things would start to get weird. The mantle’s rock would be molten hot. But instead of staying in its melted state, the mantle would turn hard. That’s because of the extreme pressure.

Moving on to the bottom of the mantle. A mere 1,000 km (600 mi) down, you would experience the force of mantle blobs. These are supercharged plumes of hot rock. And if they surfaced, they would become devastating supervolcanoes. No need to say you’d feel extremely hot.

You’d be almost halfway through the Earth, and that must mean you’re approaching the outer core. At depths of 3,000 km (1,864 mi), the outer core is made of iron and nickel. And boy, would it be hot. The temperatures around you would range from 4,500 °C to 5,500 °C (8,132 °C to 9,932 °F). At 5,000 km (2,107 mi) below the surface, you’d reach Earth’s inner core.

This giant solid iron sphere has a mind-boggling temperature of 5,200 °C (9,392 °F). And the pressure is a crushing 3.6 million times more than at sea level. Let’s hope your gravity train would be up to challenge at these extreme temperatures and pressures. I didn’t read the manual, but I’m sure you’d be just fine.

Finally, you would make it to the halfway point of your subterranean voyage. Right at the center of Earth, the mass would be equal in all directions. And you’d get to experience zero gravity.

But remember, that was just half the journey. You’ll have to do all that again, but in reverse to finish your trip. This journey would put you under a lot of pressure. It would make you hot, most likely uncomfortable and (VO: pause) rich. You did collect all the diamonds, didn’t you? Now, how long do you think it would take to get from one side of Earth to the other?

OK, it’s time I told you more about the gravity tunnel. This is a theoretical passageway through the Earth. Or simply a hole through the Earth, as I like to call it. If it’s created correctly, you could get from one side of the Earth to the other in about 42 minutes using a gravity train.

But as I mentioned before, traveling through Earth would be the easy part. It’s the drilling that would be hard. If we could engineer such a feat, it would revolutionize travel. And you would have one short but an epic journey.