[Tarpaulin]

That’s a lot of money, but as I see it the proposal would do more for society than the current administration's tax break for millionaires, and it costs a lot less.

They just had to put that in.

BTW, it would only be zero-G inside a hollow sphere at the exact center.

[Graycliff]

Lots of questions for this one.

How do they maintain the heat?
Rock density's increase with depth.

[Lokibob]

Ok, zero g in the center of the earth, 1 g at the surface of the earth, and gets less and less the further you go out. What is the max g point?

[Doctor Stochastic]

BTW, it would only be zero-G inside a hollow sphere at the exact center.

Actually, for a hollow sphere, the entire region inside the shell has gravity zero.

[Lekker 1]

BTW, it would only be zero-G inside a hollow sphere at the exact center.

I think you may be mistaken on this. The G would be zero everywhere within a hollow sphere (at least the gravity attributed to the sphere's mass).

[Oberon]

BTW, it would only be zero-G inside a hollow sphere at the exact center.

Actually, that's incorrect. I proved it in an analytic geometry class in college. The gravity is exactly canceled out at every point inside the hollow sphere.

The reason for this is as follows: Starting at the center of the sphere, as you move to a non-central point (say, to your right), the gravitational attraction between you and the part of the sphere you're approaching increases...but you're putting more of the sphere behind you than in front of you, in a ratio and at a distance that exactly balances your proximity to the point you're approaching.

It sounds complicated, but it works. Honest.

[Lonesome in Massachussets]

BTW, it would only be zero-G inside a hollow sphere at the exact center.

Nope everywhere inside. Freshman problem in Resnick and Halliday, 1968 edition.