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Science

Falling to Earth's Core in a Big Blob of Iron 325

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. :-)"
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Falling to Earth's Core in a Big Blob of Iron

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  • by Anonymous Coward on Wednesday May 14, 2003 @09:32PM (#5960300)
    And everyone on the planet was killed. So, children, remember, don't try to drill to the center of your planet without the proper tools.

    Alien 4th Grade Class on "History of Stupid Mistakes"
    • More 4th Grade Alien Papers

      "A Space Elevator Fell On My Mommy."
      "It Turns Out We Need A Magnetic Field."
      "My Sister Smells."

    • 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. :)
    • by jerryasher ( 151512 ) on Wednesday May 14, 2003 @10:22PM (#5960572)
      Crack in the World (1965) [imdb.com]

      Plot Summary for
      Crack in the World (1965)

      PageFlicker
      IMDb home PreviousMain DetailsNext Help
      Page 9 of 16

      Dr. Steven Sorenson (Andrews) plans to tap the geothermal energy of the Earth's interior by means of a thermonuclear device detonated deep within the Earth. Despite dire warnings by fellow scientist Ted Rampian (Moore), Dr Sorenson proceeds with the experiment after secretly learning that he is terminally ill. This experiment causes a crack to form and grow within the earth's crust, which threatens to split the earth in two if it is not stopped in time.

      Immortal Dialogue [bluemountains.net.au]

      Layperson: What if the crack keeps going - right around the world? What happens then?
      Scientist: Where the land masses split the oceans will be sucked in, and the colossal pressure generated by the steam will rip the earth apart - and destroy it.
      Layperson: You mean - the world will come to an end!?
      Scientist: The world as we know it, yes. As a cloud of astral dust, it will continue to move within the solar system.
      [That's what's known as "scientific consolation"....]
    • That's not really funny. The problem is that there is a reason why very power nuke bombs are prohibitted: b/c there is a chance that if it expoids in the water than H of H2O can start a reaction as there is always some % of of D and T in H and it's a matter of high enough pressure and temperature to trigger the fusion.

      Late 70s early 80s there was two extremely dangerous tests: 50 MT underwater by France in Pacific and 100+ MT underground by Soviets on New Zemlya. In second case, despte the fact that under

      • Dubious (Score:3, Informative)

        by mongbot ( 671347 )
        A fusion warhead uses a fission bomb and a reflective metallic shell to focus the intense radiation caused by the fision explosion upon the actual tritium-deuterium mix. Great lengths are gone to ignite fusion, from choosing metals with enough radiative opacity, to finding the right mixture of tritum and deuterium. The idea of surrounding water also igniting, seems odd, to say the least.

        Can you give me some kind of link or reasoning for this?

    • Oh boy, you sure asked for it...

      A little cartoon entitled "Yes"... [angryflower.com]

      Offtopic? Maybe. Graphically humorous? Hell yeah.
  • The Core becomes reality; I can see it now!

    - Seismic Instability
    - Hurricane Force Storms
    - Monstrous Tidal Waves
    - Generally Bad Shit

    Well, ok, maybe that won't happen..
    • - Generally Bad Shit

      Boy I had one of those last week. I had eaten at Taco Bell the night before. Next night I'm driving back home late at night on a rural highway when the little chihuahua wants out. I pulled over and ran into the woods and out came this molten mass that was steamin as it hit the ground. I'm quite sure it's still sinking.

  • by Anonymous Coward on Wednesday May 14, 2003 @09:34PM (#5960311)
    "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. :-)""

    That's easy for you to say. You already have your degree.
  • The end.. (Score:3, Insightful)

    by jfroot ( 455025 ) <darmok@tanagra.ca> on Wednesday May 14, 2003 @09:34PM (#5960313) Homepage
    And then when the probe stops the earths core from spinning we will send down a team to ignite nuclear bombs to restart it.
  • by sould ( 301844 ) on Wednesday May 14, 2003 @09:34PM (#5960316) Homepage
    made out of material which won't melt or dissolve in the iron

    Well...thats easy then
    • "made out of material which won't melt or dissolve in the iron

      Well...thats easy then"

      Well thats very much do able. The biggest thing that i get thinking is CHECK VALVES, they have better have a good check valve at the top of that hole. Something like oil wells use. Cause i can't think making a man made valcono magma shaft is a good idea.

      Or I guess hey lets go nuts, lets start drilling in Newark, NJ
    • Yeah we could use heat resistant foam ... Oh wait ...
  • by mao che minh ( 611166 ) * on Wednesday May 14, 2003 @09:34PM (#5960317) Journal
    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.

    • by Anonymous Coward
      What if you went from both sides?
    • Here's a question, though. Could someone design parabolic shaped tunnels between destinations for transportation?

      Suppose one built a tunnel between New York and Los Angeles that is parabolic. Then, design it with some kind maglev system to reduce friction. Could you then send specially designed cars through these tunnels with a minimum of energy expended?

      Maybe you could impart the the car with enough velocity at the beginning so it comes to a gentle stop at the end.

      Has someone already done this in Sci
      • If you were to have an evacuated tunnel*, you could could put a maglev train in that tunnel, and then give it any push, and assuming a completely horizontal track, it would arrive at the destination with the same speed, with no energy expended. Your Idea of parabolic is pretty cute, but you would just need a little ramp at the beginning to convert a little gravitational potential into kinetic energy, and then a corresponding ramp at the end. There is nothing special to a parabolic tunnel, with the vertex
    • So no, unlike a Bugs Bunny cartoon, we cannot use molten iron to dig a hole to China.

      Bull! I don't believe you.

      Next you'll be telling that rabbits can't talk!
    • by Dyolf Knip ( 165446 ) on Wednesday May 14, 2003 @10:04PM (#5960479) Homepage
      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.

      • Well excluding the whole hotter than the surface of the sun thing(which seems a tad exaggerated), couldn't you solve this problem by drilling your hole along the axis of rotation?

        Admitedly you'd then be travelling from somewhere unpleasantly cold to somewhere else unpleasantly cold, but in theory assuming you could avoid bursting into flames or filling up the whole with magma, that should solve the as you so aptly put it, stone wedgie problem.

    • Interestingly, any frictionless tunnel that you bore from one point on the earth to any other point will work this way. It doesn't have to go through the center, and it doesn't have to be parabolic. In theory, you could bore a tunnel from your house to your workplace down the street and travel there with no energy expenditure. Transit time is another issue; any straight tunnel will take the same time no matter what the distance (I think it's about 90 minutes, although I'd have to dig out my orbital mechanic
    • what about making holes on either side and aiming/aligning them properly? :)

    • by lommer ( 566164 ) on Wednesday May 14, 2003 @10:54PM (#5960706)
      Wow, 108 comments and I have yet to find one that discusses the proposition in any detail. (maybe all those fluid dynamics equations are as foreign to other slashdotters as they are to me :-) At any rate, I just finished reading the annotated paper, and I've got a few comments and questions:

      1) Why, instead of using all this iron buisiness, don't we simply use a radioactive ball of goo? This would mean that the whole blob could be a lot smaller as you wouldn't have to worry about maintaining the heat - the radioactivity can do that for you! As well, given that melting point increases proportionally to pressure, and that the pressure in near the earth's core is extremely high, you don't have to worry about getting the iron hot enough to not worry about that. The guy writing the paper does mention the possibility of using nuclear, but he doesn't give any good reason why not.

      2) Nice quote - "The correct application of this energy to open up a crack and the technological challenge of emplacing the iron should be much less challenging than the manhattan project." He does realize how difficult the manhatten project was, doesn't he?

      3) He mentions that the hole would not completely close up behind the probe (NB - this would not cause a volcano, for reasons he points out, mostly due to tube size and geometry). Why is this the case? does some of the matter get combusted into a gas and escape out the chimney? or is there something else here that makes this not violate the conservation of matter? On another thought, would it be possible to lower a second probe down this chimney?!

      4) The sensor package he discusses would look for temperature, pressure, trace + major elements, and electrical conductivity, etc. I can understand the pressure bit, but wouldn't the temperature and element sensors only be sensing the iron casing that the probe was injected with? unless he has some other method of sensing these things at some distance away from the probe I don't see how this is possible (maybe trace elements mixed with iron on the way down, but the experimental error in this would be huge). On another note, using the nuclear probe proposal in point 1, could it be possible to moderate the nuclear reaction and thus stop the probe for a bit, do some sensoring (whatever that may be, and I know I made that word up) and geology, then start up again? Also, this would be valuable for point 5...

      5) He mentions that we don't know much about working with seismic waves. Wouldn't all this iron buisiness and the fact that its fluid potentially cause problems with the seismic signal? (like distortion, etc) Given that we haven't done much encoding/modulating, and transmitting of data using seismic waves, it might be a good idea to perfect this first. The only other option I could see would be emitting a constant signal and watching how it varies as the probe descends, and then extrapolating this for data (of course, then you don't get the juicy data at the probe itself).

      There's more I could think of, but I do want to get this out, and I've got other things I should be doing. All the same, the article was an interesting read and stimulated the brain cells fairly well, even if it is completely impossible!
    • 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.

      Not quite. Gravitational force is relative to the distance between the two bodies, but it gets STRONGER as those bodies get closer. Hence Ecuadorian mountain people "weigh" less than people in Death Valley.

      In the theoretical tube through the Earth, there would be a sort of reverse LaGrange point somwehere in the tube, where the prox
  • PROBE: HOLY SHIT, IT'S HOT OWN HERE... hey, who's that guy with the horns and pitchfork.

    also, you better hope that nobody misplaces adecimal in te controls to create seismic disturbances. Earthquakes, volcanos, and other shit hollywood likes to make bad movies about.
  • by 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.
    • I'm a professor of Earth and Planetary Sciences at Washington University in Saint Louis

      Please to meet you. I'm the pope.

      This will never work.

      Gee. Do you think? Funnily enough most people here know that this idea is just a cartoon sketch of an idea; a bit of brainstorming, but apparently you don't.

      Its pure pop science, and the CalTech should revoke this guys tenure, if he has any.

      You obviously want his job. Anyway enough wasting time with you, I've got eclesiastical matters to deal with.

    • With an attitude like that, I think it's your tenure that should be revoked. I had this guy for an intro geology class my freshman year; he's an incredibly smart and incredibly cool guy.

      The sense I got from his interview on NPR was that this was just an 'interesting idea' he was throwing out, not something he was planning to try six months from now. Also, if having one far-fetched idea was grounds for revoking tenure, I suspect we'd have very few professors left.
  • by Onetus ( 23797 ) on Wednesday May 14, 2003 @09:40PM (#5960348) Homepage
    Guess they won't need to find a blob of iron.
    The slashdotting the server will receive ought to help melt it and the floor beneath it.

    Off goes the server, down, down, down ...
  • I'm no geologists, but based on what I learned in school (no doudt out-dated by now), the mantle is molten rock and probably gets hotter as you near the core. So what is stopping this molten iron from dispersing into the molten rock in the mantle?
  • by Anonymous Coward
    They are called volcanos? Why not just send a probe down a volcano and call it a day.
    • Volcanoes form when magma forces its way up through a crack in the crust.

      You want to send a probe down.
      See the problem?

      Scientist,"Ok, now we'll just head on up to the vent over there and toss the probe in.."

      *Rumblings from volcano*

      Scientist, "I can't help feeling that I've missed something crucial in my calculations... oh well."

      *scientist continues to the edge of the vent, tosses probe in*

      Scientist (excitedly),"Right! Now all we do is wait for some data! (Taps laptop) Hmm, there must be a sensor probl
  • by Anonymous Custard ( 587661 ) on Wednesday May 14, 2003 @09:42PM (#5960363) Homepage Journal
    They've found a way to get a wireless probe to connect from the middle of a molten ball of iron deep in the center of the earth, but I still can't get my cellphone to work in the subway.
  • Hmm (Score:2, Funny)

    by Raagshinnah ( 670749 )
    Imagine a beowulf cluster of those digging around :) maybe those AI students could build the probes *grin*
  • Everyone with a brain knows that the Earth is hollow! http://www.v-j-enterprises.com/holearth.html
    • I sincerely hope that no one actually believes the earth is hollow. The theory is flawed in so many ways, I don't know where to begin.

      It's like claiming that cows are more buoyant than air, and they're only held down by the force of the sun's rays bombarding them.
  • by Anonymous Coward on Wednesday May 14, 2003 @10:04PM (#5960477)
    Won't that disturb the people who live inside the earth? They may be aliens, but they have rights, too.
  • by Guppy06 ( 410832 ) on Wednesday May 14, 2003 @10:05PM (#5960481)
    "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?
    • Also, I thought that the core of the earth was populated by materials much denser than iron. Uranium, plutonium, people who watched the Bachelorette... Wouldn't the iron not actually get down all that far?
      • The core of the Earth is actually made mostly of Nickel and Iron. Heavier elements also exist but are much rarer and so don't make up much of the core. Also, there are different types of heavy elements. There are "siderophiles" like Gold, Platinum, and Iridium which prefer to hang out in Iron rather than rock and get concentrated near the core (one reason why gold is fairly rare on the Earth's crust). Then there are "lithophiles" like Uranium, Thorium, or Potassium which prefer to hang out in crustal ro
    • I'd be more worried about the device being able to withstand that pressure [...] prevent the weight of the planet from squishing it like a bug.

      That's an interesting point, but perhaps not a fatal one.

      The pressure at one mile down is quite high, but we have mines that go that deep and deeper, so therefore we can build supports that can withstand the load. On the other hand, pressure at the center is exactly zero, so there must be some penetration depth of maximum pressure, with pressure diminishing

      • "The pressure at one mile down is quite high, but we have mines that go that deep and deeper, so therefore we can build supports that can withstand the load."

        If I remember correctly, the radius of the earth is about 3600 miles.

        "On the other hand, pressure at the center is exactly zero,"

        No, because the surrounding fluid still wants to be at the center and still transmits the weight of all the above fluid to the center. The center of the earth is where the pressure will be at it's greatest, which is wh
  • I remember seeing an old 50's or 60's sci-fi movie back when I was in grade school, where idiot scientists drilled a hole down to the earth's mantle and all hell broke loose-- massive earthquakes, volcanoes erupting, the Earth starting to split apart along the mid-oceanic ridge. They fixed it by dropping an atomic bomb down a volcano just as the crack was approaching, in order to "stop-drill" the crack and saved the planet.
  • Um, hello? (Score:4, Funny)

    by rgoer ( 521471 ) on Wednesday May 14, 2003 @10:06PM (#5960489)
    We already have tons of data concerning the nature of the Earth's core. Duh. There was a documentary shot on this very subject sometime in the sixties; it showed the center of the Earth to be a rather tropical, oceanic/tropical place, where dinosaurs still roamed free on land. Big, sail-backed dinosaurs: that's all there is at the center of the Earth. This iron-ball thing sounds like a waste of time.
  • by dackroyd ( 468778 ) on Wednesday May 14, 2003 @10:07PM (#5960496) Homepage
    Won't making a crack this big in the Earths surface let all the gravity out ?

  • Geek courtesy (Score:2, Insightful)

    by SuperBanana ( 662181 )
    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 compl

    • Meant to put this in right at the top, but for what it's worth, an apology for rehashing what's somewhat of an old topic, and for being off-topic. And coming off as too cranky :-)

      I hope I have at the least added something new, and request only that people mod with care- don't just slap it in any direction(UP or down) with a knee-click reaction.

    • I agreed with you completely up until the end. This can't become a legal battle, because if it does, where do you stop the amount of links considered for a slashdotting? 2,000? 10,000? 100? It all depends on the system. You noted that, but how could you communicate the load you can handle? At any rate, I think it shoud be more of a courtesy e-mail rather than a requirement for posting. Imagine how little we see if it were required to have an e-mail from the webmaster of the site about to be linked.
  • they still shouldn't go fishing for research topics at the movie theater!! :)
  • I heard the good professor interviewed on NPR this afternoon and one of the questions was "do you really think this will work or is it just a mental exercise" to which he responded that there are no blueprints, and it is basically a mental exercise but that you have to start generating the ideas somewhere.
  • by mnmn ( 145599 ) on Wednesday May 14, 2003 @10:12PM (#5960521) Homepage
    Firstly the probe will have to have all its parts be heat resistant, else should have an internal cooling method, and not just one of those Duron fans. And then the probes net density should be the same as the molten iron, so it doesnt float over it and touch the lava. Better yet it should have a way to adjust its own density, maybe eject some ballasts. Since most electronics are less dense than iron, to balance it, the probe should have material that has more density. I wonder if lead would do, or should we try Uranium.

    I think the biggest problem will be the earths crust. Where can we find or drill a hole large enough vertically straight?? Hawaii?? Mount Fuji should be a better place but do we really want to drill a hole in that given its history?

    And finally the idea that most of the space under the crust is molten mantle is still just a theory. Maybe 100 meters down the iron will just sit on another mass of rock that just happens to be there. And I dont know how will it find and go through cracks. If like water its allowed to drain, it will spread thin enough to damage the probe, so LOTS and LOTS of molten iron should be used on a vertical shaft like mount fuji.

    I think radio waves of the right freq can travel within the mantle, so we could have large satellite dishes pointed into the ground. Heck we could even send bombs to China. Designer earthquakes!
    • "Where can we find or drill a hole large enough vertically straight?? Hawaii??"

      The advantage of Hawaii is that the hole is already there, open, and has been for a decade or two now. As long as you can handle the upward current, just drop the thing into the Pu'u O'o Vent and be done with it.
  • My word, this has been tried before! Well, maybe they saw the same 1965 documentry [imdb.com] that I saw and decided against thermonuclear weapons for diggig the hole, but still, same idea.
  • by asv108 ( 141455 ) * <asv&ivoss,com> on Wednesday May 14, 2003 @10:21PM (#5960570) Homepage Journal
    Andy Rooney was nuts [cbsnews.com]..

  • 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.
  • by Winterblink ( 575267 ) on Wednesday May 14, 2003 @10:33PM (#5960612) Homepage
    ... the opening scenes of a Jerry Bruckheimer film.
  • Data? What data? (Score:5, Interesting)

    by Steve B ( 42864 ) on Wednesday May 14, 2003 @10:43PM (#5960646)
    As the probe falls, it sends data back using seismic signals

    What kind of information about its surroundings could the probe pick up from inside all that molten iron?

    • What kind of information about its surroundings could the probe pick up from inside all that molten iron?

      Heat and pressure...you know...the things that typically melt probes here on the upper crust.

    • Maybe I'm misunderstanding, but wouldn't the probe, encased in iron, find that somebody stuck quite a bit of really hot, compressed iron down there.

      And wouldn't the probe, most likely not being as dense as the iron, reach a pressure point where it would float and/or be crushed? i.e. stuck in the crack while the iron continues down.

  • could we maybe test this idea on some planet besides the one we're living on? how about doing this on the moon?
  • Ok... i'm no geology expert... but i'm thinking this is a really bad idea.

    A nuclear blast on the surface has proven to be done with minimal global harm, with the exception of radiation and minor fallout of radio active isotopes that humans are generally not exposed to, some found in nature... or rather, those dead places where no shit grows, some with a really short half life generally not something you'd want in your hair

    Under ground testing has been done with minimal impact on the globe, just some radia
  • I what electronics package are they going to use to operate above the temperature of iron?
  • ...straight to Hell. :)

  • How much for ticket in an asbestos lined capsule, so we can go on a "Journey to the Centre of the Earth"? I want to go down and pick me up some diamonds.
  • I read an article on this earlier today and my only question was why make a crack in the earth? Why not throw the probe in an active vulcano or where the tectnoic plates separate?

Where there's a will, there's a relative.

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