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

The end..

[jfroot]

And then when the probe stops the earths core from spinning we will send down a team to ignite nuclear bombs to restart it.

For the coming "hole to China" questions/jokes

[mao che minh]

People might actually crack a joke concerning the possibility of boring a hole to China using this technique. I would like to take the time to point out that this isn't possible using this technique.

If you ignore friction, the rotation of the earth, and other "complications", then it would be possible to use this technique to bore a hole right through to China. Imagine the sudden appearence of a tunnel that goes straight through the Earth. If the mass distribution in the earth was uniform (which it is not), a person could jump into this tunnel and then come back up on the surface on the Earth on the other side (China), much like the motion of a pendulum swinging up and down again. Assuming that the journey began with zero initial speed (simply dropping into the hole), your speed would increase and reach a maximum at the center of the earth, and then decrease until you reached the surface on the other end, at which point the speed would again be zero. The gravitational force exerted on the traveler would be proportional to his distance from the center of the earth: it's at a maximum at the surface and zero at the center. If there were no friction, there would be no energy loss, so you could oscillate into and out of the tunnel forever.

Given the physics behind this theorized stunt, boring a hole clear through to China would be impossible. It would require some extra application of force to tunnel "upwards" after reaching the Earth's core.

So no, unlike a Bugs Bunny cartoon, we cannot use molten iron to dig a hole to China. Not like this, anyways.

This will never work

[Anonymous Coward]

I'm a professor of Earth and Planetary Sciences at Washington University in Saint Louis (please don't hold wu-ftpd against me).

This will never work. Its pure pop science, and the CalTech should revoke this guys tenure, if he has any.

Worst. Idea. Ever.

Totally ignoring the *real* problem

[Guppy06]

"made out of material which won't melt or dissolve in the iron"

I'd be more worried about the device being able to withstand that pressure. I fail to see how surrounding the probe with molten iron (or any other fluid, for that matter) will prevent the weight of the planet from squishing it like a bug. Or does he plan on violating the laws of physics at the same time?

Geek courtesy

[SuperBanana]

I hope he doesn't mind being Slashdotted.

Hint- ask, next time. I don't care if it's editors or story submitters, if the site doesn't seem like it'll take it(ie, it's not a big-fish site), or if it's a nonprofit, ask first.

This ain't "news for nerds", it's "linkage with discussion", and it is pretty embarassing that slashdot STILL doesn't bother to do jack about the problem, simply hiding behind a few pathetic excuses in the FAQ about it being "too complex", whcih is complete bullshit; look at how complex the comment rating system is...but keeping a mirror in sync is rocket science? Hogwash! Robbing sites of statistics? Find me a site admin who would rather keep his/her 'statistics' than keep his/her site running. Absolute hogwash. Copyright? That's why you bloody well get off your editor's chair and ask them first.

The more truthful answer is, they(and OSDN) can't afford the bandwidth either- and have absolutely zero interest in spending any time dealing with the headaches they cause, probably because slashdot is so low-margin. I applaud the first person that sues for damages, because slashdot has acknowledged the problem(and its results), for one. It'd teach some livin-in-fairy-land nerds some hard-knocks-of-real-life lessons.

Re:There's the problem....

[WolfWithoutAClause]

That'd work, but only if there was some place for the heat to go. Can't get rid of heat, right, all you can do is move it around? Hard to do that when you're surrounded by friggin molten iron.

That's not quite true. Consider a refrigerator. It consists of an insulator layer and a heat pump. When heat leaks past the insulator it gets sucked back out and dumped.

So you could do the same thing in the earths core, use brick as the insulating layer, and run a refrigerator to pump the heat out, and increase the temperature of the molten iron just outside the insulator. Molten iron is a good conductor of heat, so convection would carry the heat away from the probe.

I must admit I'm more worried by the unbelievable pressure of hundreds of miles of rock, oh yeah, that and the nuclear device they'd need to start off the crack...

Re:And that's how the Earth broke in two

[MikeFM]

While I think massive destruction as a result of such a probe is unlikely I would rather we wait fo do such intrusive tests until we've colonized a few other worlds. We haven't even explored the space near us or our own oceans so why take that minor risk of destroying all humanity? In a way I feel the same way about things like nanotechnology. Anything that has the chance to be a global killing experiment should be done only after we've got a backup plan. :)

A solution for our nuclear waste?

[Andover Net]

Perhaps it might be worth while, as a way to dispose of our radioactive nuclear waste. I believe that Earths core is theorized to be radio active anyway. The hole closes up after itself as it goes down, so it should be a nice clean way to go.