Journey to the centre of the earth

[andytheplumb]

If i was to dig a whole in the ground deep, i mean real deep to the centre of the earth for example, now forgetting the fact it is hotter than a snakes ass in the water, if i were to jump in (and not get fried cus im wearing my super thermal decreasing body suit) when i got to the middle what would happen?

[Ollie_P]

You'd only be falling at terminal velocity - about 125-130mph. Once you got to the 'middle' your inertia would carry you through. Since you'd now be travelling away from the centre you'd be subjected to gravities pull, much like a space shuttle trying to leave the earth surface. Unfortunately a space shuttle has enought thrust to counter gravity where as you have 12 stone travelling �125 mph. - you wouldn't escape gravity. So you'd yo-yo back & forth until the forces on you from all sides was equal & then you be stationnary in the middle.

[Ollie_P]

Oh and that answer assumes you went through the middle & dug out to the other side. If not you'd just go splat on some very hard inner core. Oh and the pressure is about 3.5 million Atmospheres so your thermal suit best be pretty sturdy.

[oligopoly]

you cant possibly answer the question that confidently, now can you Ollie_P. Its a theory. It might happen; it might not. You would never know for definite

[Ollie_P]

You're right oligopoly, we will never know for definite. I never said it was a definitive answer. I doubt andytheplumb asked the question hoping that hundreds of people would respond with "dunno, we'll never know". Instead of being negative do you have anything positive to add to, what I think, is a really interesting question?

[Loosehead]

don't talk rot oligopoly, gravitation is well understood. Are you saying if I jump out of a plane I might not hit the ground? Ollie is correct.

[tell-me-more]

Surely if you dug through the centre, there'd be nothing to supply the gravitational pull. The pull is a property of the mass isn't it? Remove the mass, and you remove the pull, surely?

[Catso]

And don't forget that gravity wouldn't be so straightforward once you got an appreciable depth down. There would be a great mass above you, as well, creating an attractive force back 'up' the hole.

And, when you got to the centre, wouldn't you be weightless? There would sureley be an equal attraction in all directions, thus cancelling out.

[Loosehead]

Catso is correct you would float in the hollowed out centre. Tell-me-more most of the mass of the Earth is still there in this thought experiment.

[dawkins]

you would be attracted to the side of the hole by gravity and go splat. Why don't people in Australia fall off the earth?

[tell-me-more]

Sorry, yes, I meant you'd remove the traditional "inward" pull towards the centre of the earth.

[mibn2cweus]

Ignoring the intense heat and pressure of subterranean environments and the difficulties of constructing a hole under such conditions:
Since the Earth is spinning you would not want a hole straight through the centre but one that curved to compensate for your lateral momentum, (unless it was from pole to pole). Near the Equator you are traveling horizontally at over 1600 kph, while the centre of the Earth is not moving in this direction relative to the surface. As you accelerated toward the Earth�s center of gravity the curve would tend toward the centre of the Earth however your target would be missed due to the horizontal component of your trajectory.

Further ignoring deceleration due to drag (air resistance) etc., if your hole continued in this fashion you would arrive back at the Equator but not on the opposite side of the Earth.

Under similar circumstances a hole from pole to pole along the rotational axis of the Earth would aim directly toward the centre of the Earth and your maximum velocity would be reached at the centre, although your rate of acceleration would diminish since the gravity of mass existing in overlying spheres no longer contributes to your velocity. If your hole continued to the other pole you would begin to decelerate after passing the centre and would reach zero velocity when you emerged out of the opposite side of the Earth.

[Hamish]

Err Loosehead - theres a one in three chance that you would hit the ground.....its more likely you would hit water as the earth is covered by about 66% of it!

Couldnt resist it sorry.

[dawkins]

nah you would hit the side Mibn.

[mibn2cweus]

dawkins, I take it that I could not persuade you to be the first to go through the hole. What if I made it a bit wider? I promise not to drop a marble in the other end