thought experiment

MusashiStyle · #1 04-19-2007, 12:30 PM

Suppose I were to drill a hole through the earth (i.e. in one side and OUT the other) with radius 1millimeter. The hole would be lined with a metal casing and held in vacuum. The hole would be drilled exactly from the north to south pole.
Now I drop a tiny steel sphere into the whole from 1 meter above ground. what happens?

assume earth is perfect sphere (uniform density).

arahant · #2 04-19-2007, 01:17 PM

it oscillates from one side of the earth to the other, no?

RoundGuy · #3 04-19-2007, 01:42 PM

Well, not quite sure how you're going to transition the metal ball from an atmosphere one meter above and drop it into a vacuum -- but assuming you could, wouldn't it travel north to south for constantly decreasing distances until it ultimately ends up in the exact center of the Earth?

arahant · #4 04-19-2007, 01:45 PM

Why would the distances decrease? I assume OP intended frictionless, non-deformable spheres and all that...

Duke · #5 04-19-2007, 01:54 PM

You'd wear a hole in the brane after some time and create a rift in spacetime.

yukoncpa · #6 04-19-2007, 02:11 PM

[ QUOTE ]
it oscillates from one side of the earth to the other, no?

[/ QUOTE ] Yes, and as long as the tube is frictionless, the process should continue forever.

straightdope

Neuge · #7 04-19-2007, 02:26 PM

[ QUOTE ]
[ QUOTE ]
it oscillates from one side of the earth to the other, no?

[/ QUOTE ] Yes, and as long as the tube is frictionless, the process should continue forever.

straightdope

[/ QUOTE ]
Assuming we also ignore the effect of the Earth's magnetic field. The ball is steel after all.

Roland32 · #8 04-19-2007, 02:33 PM

This has been discussed I believe gravity will keep the ball in motion back and forth from the center.

Valentyno · #9 04-19-2007, 03:01 PM

[ QUOTE ]
You'd wear a hole in the brane after some time and create a rift in spacetime.

[/ QUOTE ]

An effect that would be easier to simulate by turning that hole into a million-cc hookah.

RoundGuy · #10 04-19-2007, 03:03 PM

[ QUOTE ]
Why would the distances decrease? I assume OP intended frictionless, non-deformable spheres and all that...

[/ QUOTE ]
Not sure. Just sounds right to me. I'm still trying to figure out the transition to a vacuum from a one meter drop.