If I were to dig a hole and keep digging would it be possible to get to the other side of the world (gravity)?

Question

OK so I dig a hole and keep digging (forget about the heat of the earth's core and any oceans or whatever. As I can dig half way (because of gravity's pull) would I have to start digging upwards to get through to the other side. But how can I dig up if gravity will just pull be back down ? Would I float in the centre of the earth or something? Imagine there was a huge tunnel from one side of the earth to the other and I jumped down it, what would happen when I got to the centre of the earth with regards to gravity? Thoughts??

Answer 1

Neglecting oceans, heat and liquid core of the earth, you raise several interesting questions regarding gravity. Digging to the center of the earth and up the other side would be much like digging down to a subterranean cave and then back up in another location (only you are going much deeper!). At the center of the earth you would be surrounded by mass on all sides pulling equally on you and you would float. If you jumped into a hollow tube through the earth, you would start with maximum potential energy (height above earth's center and zero kinetic energy or velocity). At the center all potential energy would be converted to velocity and you would speed to the other side of the tube and land on your feet (zero velocity again) neglecting air resistance and friction. If you didn't land on your feet but dropped back into the tube you would continue to oscillate forever, neglecting friction.

Answer 2

If you can dig the tunnel perfectly frictionless and airtight, and then pump out all the air so it's complete vacuum, you might have a chance. It doesn't matter if the gravity is different near the center of Earth (it is) as long as there's an equal and opposite effect after you pass through the center. If everything is perfect, you should barely be able to grab ahold of the surface when you reach China or wherever. But if you screw up even a little bit, you won't reach China, and you'll end up more or less stuck in the center of the Earth. If you build this crazy tunnel, install a ladder, just in case. Just cut some little notches in the side of the tunnel. A full-scale ladder would kill you if you touched it at high speed.

Answer 3

As long as you leave aside the whole molten lava problem, then yes, you would dig down 'till you reach the centre where you would weigh nothing. You would then have to dig up to the other side.

If there was a huge tunnel to the centre of the earth and back out the other side, you would jump down and fall to the centre and probably shoot past it due to momentum and then get pulled back. After a few oscillations you would end up floating at the centre of the earth.

All a bit sci-fi though isn't it? I mean, lets bring that molten lava back into play and the earth's core itself. Talk about burnt to a crisp! And what about the volcanic implications of a hole right through the crust?

Answer 4

Great question. If there were a hole straight through the Earth and you jumped in, you'd go flying past the middle and up the other side almost to the rim, but gravity would pull you back to the centre. If you CRAWLED in, you'd float in the middle of the Earth since the gravitational pull is all around you.

If you DUG in, you'd, as you said, get hot in the middle of the Earth and then just start to dig up the other side. It would be hard to "dig up" because dirt and rocks would be falling in your face, and you'd be working against gravity, but maybe that would help because you wouldn't have to life any weight, just carve it away.

And the dirt and rocks and stuff would fall down under you and reach the middle of the Earth as it fell and just ultimately hover there. If you went back down the hole, you'd have to push it all away in order to get up and out the other side.

Theoretically!

Answer 5

Yes you would have to start digging up to get to the other side once you passed the center.

Neglecting air resistance, if you jumped in a tunnel going through the center of the Earth, you would accelerate until you passed the center and then you would decelerate until you got to the opening at the other side and then would start falling back again.

You would continue to oscillate in this fashion forever until another force stopped you.

You can calculate what you terminal velocity would be and how long it would take for each oscillation.

x = 1/2gt^2 where x is the radius or the Earth and g is acceleration due to gravity.

t = (2x/g)^1/2 = (2*6400000/9.8)^1/2 = 1142 sec = 19 min to get from the surface to the center...thus each oscillation (returning to the starting point) would take 4*19 = 72 min.

v = at = 1142*9.8 = 11200 m/sec = 11.2 km/sec at the center...pretty fast!

Answer 6

If you dug through the centre, just as you passed the centre, all the earths gravity would escape, you would shoot out of your hole like a cannonball and out into space, but then everything on the earth that is not bolted down would also be floating in space

Answer 7

At the centre of the Earth your weight (mass x gravitational force) would be ZERO - due to the gravitational force at this point being zero.

From GMm / r - it can easily be seen that the radius at the centre of the planet is 0, ans therefore so would be your weight.

You would still have mass of however many kilograms you are.

Answer 8

i wish we could vote for best question,i like this one.if you are still in h.s. or even if your in college you should write a short story for composition class based on the best answer, which if you leave out reality, i think was given by robin.well good luck with the big dig,see you on the discovery channel!

Answer 9

the terms " Up & down" are relative, so is gravity. So objects will always fall downward relative to you, and you would go downard relative to me, but upward relative to the opposite side of the world.

Answer 10

The hole would collapse long before, as the mantle of the earth is a molten liquid.