Re:How to destroy the Earth (completely)
by jules on Sunday June 20, 2010 @09:42PM
(#1447634)
Not if the black hole carved a spherical cave there. The forces in all directions cancel each other out inside the spherical cave.
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In the perfectly spherical earth hypothesis, being the center of mass in the black hole, wouldn't there be a resulting force towards the center, although very small?
[EDIT] Hmm I think I see the point. The resulting force would be proportional to the ratio (black hole mass / earth's mass). Very small indeed.
No, that's irrelevant: http://hyperphysics.phy-astr.gsu.edu/hbase/mechanics/sphshel...
That's for a hollow shell.
For a solid sphere, there is always force toward the center. (And the closer to the center the lower the force, reaching 0 in the middle.)
No, the force is EXACTLY zero, not just very small.
Inside the cave yes, but not when it's inside the solid mass of the earth. Inside a solid sphere the force is toward the center.