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5/24/2007 7:31:27 PM

Quote :

"I was talking about the diameter of the hole. The idea was to drill a hole along the axis of rotation for the earth then let the freefaller drop down that hole. "

So was I. I was thinking that realistically you couldn't fall on a straight path through the earth (assuming you could even realistically drill a hole through the earth...), but you could still dig a curved hole, it's just that when you look through it, it would just look like a cave. BUt if you dug a hole straight through the earth, it would have to be massive, and when you looked through it, you would see through the Earth.

5/25/2007 12:04:59 AM

^ah ha, I think I see what you mean.

5/25/2007 11:03:57 PM

I remember in PY205 that if you could dig a frictionless hole and just fall or slide down it, it would take two hours, no matter if you dug it straight down or managed to make one from fayetteville to raleigh. Of course, I've forgotten most of the calculations, and I don't believe it too in to account any weird effects of rotation, but thats what the proffessor came up with.

5/26/2007 9:43:11 AM

OK, here is a question from a liberal arts major . . . wouldn't the rotation of the earth mean that the mass is rotating around you thereby guiding you (somewhat) through the hole preventing you from slamming into the walls (or more accurately, the walls from slamming into you)?

[Edited on May 26, 2007 at 10:27 AM. Reason : )]

5/26/2007 10:26:05 AM

Consider a uniform sphere with a hole drilled through the center. The axis of rotation is aligned with that hole. The gravitation caused by that sphere is uniform in time. In order for the gravity to be different the distribution of mass would have to change.

In the case with a curved hole things change a little, but the effect of being away from the axis of rotation would be greater.

Now the question arises: is it possible to design a hole that a person could drop through it and never hit the wall even if it were only a couple feet across. It would be possible of the hole were devoid of air and the person were dropped in a capsule (this is because friction due to a fluid is an unpredictable thing).

5/26/2007 11:09:57 AM