@Susquatch - Here is my question- if you drilled that hole, then installer a casing and dropped in a steel ball. Would it come out in Australia or stop at a the center of the earth?
(assuming that: the casing didn’t melt; the hole was straight; and you know how to drop a ball into a casing)
It depends...... LOL!
I could stop there, but that's no fun.
1st of all, a hole from Southern Ontario (covers you and I) actually comes up out in the ocean SE of Australia. That's why I said nearest place.
So we would all be drowning in Antarctic Seawater as soon as we removed the drill. No time for dropping balls. Just run like hell toward Vancouver Island.
2nd, we would have to make a zillion assumptions, but as dumb Engineers, you and I are used to that. So......
Assuming zero air compression in the casing, and zero air friction, zero magnetic imbalance, zero drill casing friction, zero radiation decay forces, a nonrotating earth with no moon and no tidal forces, zero correolis effect, a homogeneous gravity distribution, and ball dropped precisely 22.5 minutes before sidereal true midnight, no temperature affects, and jupiter, venus, and mars all at opposition, the ball should accelerate toward the center of the earth and then decellerate after it goes past center slowly decellerating until it reaches the surface of the ocean at the other end about 45 minutes later. Then it would turn around and head back to us for the return trip about 1.5 hrs later, then repeats over and over.
Of course, we really should take relativity into account, and in this case, the ball will think it didn't take as long as you and I measured. And we don't really know whether or not dark matter and/or dark energy exist in greater theoretical concentrations in planetary cores.
If you bore the hole, I'll drop the ball! Go!
