Falling to Earth's Core in a Big Blob of Iron

Colin Douglas Howell writes "Um...wow. I found this idea via the BBC, (see also the Nature article), but it's really worth reading the annotated paper on the subject. (Gotta love the title.) Basically, you drill a hole in the crust, blast a big crack in it, inject a huge mass of molten iron with a little probe floating inside (made out of material which won't melt or dissolve in the iron), and let the iron mass sink to the core by gravity, carrying the probe with it. (The initial crack grows downward as the iron sinks.) As the probe falls, it sends data back using seismic signals that can be picked up with a gravitational wave observatory like LIGO, but coupled to the ground. Of course, there are enormous problems with the whole thing, but it's still cool to read about. To me, the idea is even neater because it was dreamed up by Dave Stevenson, one of my old professors (and one of the best professors I've ever had). I hope he doesn't mind being Slashdotted. :-)"

Comments

Re:For the coming "hole to China" questions/jokes

[Dyolf Knip]

Best case scenario (i.e., no air, no uncomfortable smacking into the surrounding rock at speeds normally reserved for outer space and particle accelerators, that sort of thing), you'd come just as far away from the center of mass of the planet as you started. So as long as your 'jump point' is higher up than your destination, you're fine. Just hop in, fly by rock hotter than the surface of the sun, and then pray to gods you don't believe in that someone'll catch you so you don't start on your return trip too early.

However, I think the pesky rotation problem will do you in anyways. Linear velocity at the equator exceeds Mach 1.5; at the exact core it's essentially zero. Dropping down a hole does not magically rid you of that sideways momentum, so you will probably be getting a stone wedgie long before you even hit the mantle. You'd have to stick a rail guide along the side which, since frictionless unobtainium isn't yet in mass production and Hotblack Desiato has first dibs on the stuff anyway, would cause you to lose some of that precious inertia on the way down, thus requiring that you expend power getting yourself up the last bit.

Assuming that I were particularly interested in going to China in the first place, I'll just take a cruise, thank you very much.