If we drilled a hole all the way through the earth, would we fall in it?

Question

Would we achieve weightlessness at the centre of the earth?

If we are attracted to mass would we stick to the sides instead?

Answer 1

Let us first assume that the hole is an ideal system of passage then anything falling, or of course rising, through it will experience total weightlessness at the centre. All gravitational forces acting upon an object will cancel each other out to induce a state of momentary weightlessness. We must also assume that he hole is exactly of the size of the object in the hole – like a cannon bore for a cannon ball. Or the falling object must stay in a straight line at the centre on a uniformly drilled hole; and that there are no air currents or vapours around to deflect the movement of the object. It seems that the object will not then stick to the walls of the hole anytime during it motion. And that it will fall straight through to the one end and then back to the other, and so on, coming to complete rest at each end.

Although there will be less mass both at the top and at the bottom of the object as the mass of the Earth would have been removed by drilling. The accumulated mass on both sides however will have a mutually cancelling effect.

The mass on all sides perpendicular to the bore of the hole however will undergo a gradual change relative to the position of the object in the hole. The mass of the Earth around the object will increase gradually as the object will travel from the brink further into the core of the Earth where it will be at its thickest. This gradual increase and then decrease in the mass around the object acting perpendicular to its motion will again have no effect on the object as the mass on all sides will produce an equal amount of gravitational pull – to produce mutually balancing effect.

The motion of the object will be simple but it is an interesting situation. It seems that the object will experience a fall and then another fall from the other end; or one might like to say a rise to the one end and then another rise to the other. The mass will move with a maximum speed at the centre of the Earth in states of deferential weightlessness. This will go on forever in form of a simple harmonic motion - or an oscillatory motion with the centre of the Earth as the centre of the oscillation, and the amplitude the radius.

However in more realistic and Mathematically accurate situation, after many oscillations to a fro in the bore of the hole, the object will eventually and gradually come to a standstill at the centre of the planet.

The thickening of the mass of the Earth at the centre like all other spherical objects will make it less possible every time for the object to reach the same amplitude as that of its previous oscillation. So the amplitude will gradually reduce to zero. And this is how planets are formed at the first place.

Answer 2

Not exactly sure. Because we are pulled down by gravity cause the center of the earth is so dense. So if you drilled a hole through the center.. You would either
A. Stick to the sides of the hole on the walls of the core..
Or
B. Balance out in the very center and yes, be weightless.

Answer 3

We would oscillate back and forth...as you jump into the hole you have made (and are maintaining against the super-pressurised molten interior of the earth with some kind of force-field) you accelerate towards the centre of the earth. If there is no air resistance in this hole you will just get faster and faster....but your rate of acceleration will gradually diminish as the gravity lessens closer to the centre (see my reply to your earlier question). You reach a maximum velocity at the middle but shoot through and carry on out the other side.

As you whizz towards the other side of the planet, gravity starts kicking in again and slows you down. By the time you reach the far side of the hole you will stop moving altogether for a brief moment. Now's your chance to make a grab for the edge....

If you don't manage to grab the edge you fall back down and the process repeats itself!

Of course, in the real world, you would have a) air resistance and b) apparent forces that would cause you to bounce back and forth against the walls of your tunnel. These would act to slow you down and sap away all the potential energy you started with when you first jumped down the hole. Which means that you won't quite make it to the other side....you'll just oscillate back and forth for a while like a pendulum slowly losing energy, until you come to a halt in the centre.

Though if the heat hasn't killed you you are probably meat paste by then anyhow!

Answer 4

You would fall part the way through, then oscillate back and forth for a while before finally settling in the middle of the earth. This is because earth' gravity acts towards the centre/core of the earth.

Let me know how you get on.

Answer 5

At this end we would be subject to the forces of gravity and if you fell in/or jumped, you would travel into the hole ( to the centre), it is not a realistic question but does pose some questions on established laws of physics. My guess would be that as you approach the centre you would keep going as your momentum would be greater than the opposing force of gravity at the other end.
You would not stick to the sides as masses repel at close distances.

Answer 6

Gravity would draw you to the centre of the mass, so that you'll supply up falling once you reached the centre of the earth, assuming a extremely homogenous earth. Inverse sq. regulation has you "weighing" a lot less the further you flow far flung from the earth. hence in a extreme flying plane, you may want to weigh only the slightest bit below you do on the earth's floor.

Answer 7

You would be effectively weightless, but the moon and sun etc would effect your weight.

Did you know that if we hollowed out the middle of the earth (so it was just the crust - a kind of shell), and then went inside, you would be weightless anywhere on the inside, not just the middle.

Answer 8

I'm not even sure drilling a hole all the way through the earth is possible. Eventually you're going to run into the core and magma and it would be too hot to drill.

Answer 9

You'd only fall in if you stood too close to the edge and tripped...
If you wanted to get out the other side, you would need to propel yourself into the hole at a great speed, otherwise gravity would pull you back to the centre.

Answer 10

Ed Zotti says it depends on whether or not there was friction (at least air) slowing you down. If not, you'd bounce back and forth forever. If so, friction would slow you down to the point where you'd get past the center, but slowly, then fall back, oscillating toward the center until you came to a stop. At the center, you'd weigh nothing (I love the sound of that!), but you also would not be able to get out, unless you had muscles sufficient to climb out, which frankly, don't sound likely.