As for compression, I was thinking more of the forces involved than the physical solid core of the earth, thus imagining that two things could occupy the same space at the same time – why not?

If there were a tube, presumably we would have the ability to negate any dangerous effects, but probably not the smarts to ensure that people don’t jump in from opposite ends at the same time, or the ability to protect it from terrorists.

Quick! Build a fence to keep them from stealing our landscaping jobs!

In the best case scenario, you might be hitting 400 or 500 mph at the core, which is about 17,000 mph slower than you need to pop out the other end. Even if you wore a special suit to keep out the ferocious heat, you’d be forced to live out the rest of your life virtually weightless at the center of the earth.

Also, I would want to make sure that nobody’s jumping from the other side while I’m in there.

Thanks for the response. You’re right. When I said, “worst-case scenario,” I meant having all the gravitational force concentrated in two forces operating in direct opposition to one another — meaning the scenario most likely to pull you apart. But you’re right to say that the overall gravitational forces at the center of the Earth would be greater than that at the surface, absolutely.

post: und zwar hier.

I’m not so sure that’s the worst case scenario. After all, gravitation scales inversely with the square of distance, and in the center of the earth, you are closer on average to all parts of the globe than standing on its surface.

Still, I agree that it probably wouldn’t be enough to overcome the cohesive forces holding your body together.

You’re sitting on the Earth, right? Imagine half the gravity acting on your body right now was above you, and the other half was below you — do you think that would be enough to pull you apart? That’s an oversimplification, but also the worst-case scenario. You wouldn’t be pulled apart, you’d just be weightless — and intact.

Forget for a second that the body is traveling at all. Let’s just say that at the very center of the Earth, there is a hollow center. So picture a spherical hollow room at the center of the Earth surrounded by miles and miles of rock around. If a person were to be placed in that room, would the gravitational forces generated by the mass all around him rip the atoms of that man’s body apart? No acceleration involved…

’nuff said.

“Your initial acceleration would be the surface acceleration of gravity but the acceleration would be progressively smaller as you approached the center. Your weight would be zero as you flew through the center of the Earth.”

and

“If you drilled a hole through the center of the Earth, the acceleration of gravity would decrease with the radius on the way to the center of the Earth. If the Earth were of uniform density (which it is not!), the acceleration of gravity would decrease linearly to half the surface value of g at half the radius of the Earth and approach zero as you approached the center of the Earth.”

(That was actually a question on Car Talk once.)