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

And that's how the Earth broke in two

[Anonymous Coward]

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"

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. :)

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

[axxackall]

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 underground there was just a limited amount of water, the outcome was much greater than predicted. The shock wave did hit towns in North Russin in thousands of kilometers. The estimtaed energy after all measurements exceeded the originally calculated energey on more than 20 % - that's possible ony b/c the water underground has been involved in the fusion.

So, if they will make too intensive explosion than it's a big chance that they will miss something and trigger something they would not have planned originally. The outcome may include global cracks in the tektonic platforms and can be very catastrophic.

So, please, no more nuke/fusion exploisions - better invest money, resources and efforts into interplanetary communications: I want my vacations in Europe. You got it right - *THAT* Europe :)

Retro-revenge.

[Anonymous Coward]

"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.

Re:Retro-revenge.

[Old Uncle Bill]

If you still have that guy for a prof tell him to put the pipe down already. Or share. Obviously he's getting the good shit.

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.

There's the problem....

[sould]

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

Well...thats easy then

Re:There's the problem....

[Dyolf Knip]

And you don't want to get rid of the heat too quickly either. It has to be hot enough to keep melting the rock as it goes down.

Oh I wouldn't worry about that. After the first few miles, the temperature of the surrounding rock would be enough to keep the iron molten. Ever see pictures of lava moving through water? Kinda like that, only instead of being chilled on the outside and kept warm from the inside, it's the other way around.

Besides, if your probe's cooling system is good enough to actually chill several million tons of iron whilest encased in liquid silicate rocks, you could really dispense with the whole molten iron thing and just make the thing dense and massive enough to fall of its own accord and provide it with a heat source to keep the outside piping hot while your magical freon unit maintains room temperature on the inside.

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:There's the problem....

[WolfWithoutAClause]

The refrigerator must also necessarily generate thermal energy during their operation.

Yup. Nothing is 100% efficient. In fact there's a theoretical limit to how efficient it can be which is the Carnot cycle.

So, if we assume the refrigerator starts out at the same temperature as the rest of the probe, its temperature will rise above that of the probe, causing heat to flow from the refrigerator to the probe.

No. The waste heat flows out to the hot iron outside where it is conducted away.

This will cause the refrigerator to have to transfer more heat, which means more heat generation, and since the heat generated will always outpace the heat transfer, the probe melts.

No. The infinite series converges to a finite value, because the fraction of heat pumped is larger than the waste heat generated. It needs a power source of some kind of course to drive the refrigerator. Because you have a heat sink in the external iron, you can generate plenty of power.

And it melts faster than if there had been no refrigerator at all.

Let me guess, you're not real strong on thermodynamics? Please don't take up refrigerator design is all I can say.

Re:There's the problem....

[barakn]

It doesn't work by melting the surrounding rock. Its high density forces the crack open in front of it, and it is molten merely so that it can flow into the advancing tip of the crack. And no, the surrounding rock after a few miles will not be hot enough to keep the iron molten (not until you reach the outer core). The iron, however, does generate heat from its own gravitational potential energy.

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.

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

[Anonymous Coward]

What if you went from both sides?

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

[hazem]

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 Science Fiction? Has anyone ever tried it in reality?

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

[corsec67]

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 in the earth, and the parabola opening up.

* Evacuated means no air, not that there was a recent fire drill.

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.

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

[aerogeek]

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 mechanics notes to verify that), and you can get better transit times with different trajectories. This is all assuming a uniform, spherical earth, no friction or drag, etc.

Step 1: Draw up plans for frictionless tunnel
Step 2: ???
Step 3: Profit!

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

[peculiarmethod]

so what you're saying is.. and stop me if I'm wrong here, is that if we can amass a very VERY big exposition, we might blow a hole into the corona, dropping an improved version of these probes onto the surface of the sun, and create a beowolf cluster.. where we can cause siesmic dusiturbances which will (previosuly worked out) distribute photons in a pattern out of the corona (sun spots, flare distribution) which we will be able to reduce back into a readable data stream for data collection of the suns various environmental variables, and anonymously share not proman nudies.

is that what you ewre suggesting?

pm

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.

Re:This will never work

[WolfWithoutAClause]

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.

Blob of Iron? More like a slashdotted server

[Onetus]

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 ...

Are they sure this will work?

[jrl87]

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?

Why not use cracks already here?

[Anonymous Coward]

They are called volcanos? Why not just send a probe down a volcano and call it a day.

Re:Why not use cracks already here?

[ColaMan]

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 problem, the probe seems to be going upwards.... What's that rumbling noise?"

*volcano proceeds to erupt*

Scientist,"Ahh! it burns! it burns!!"

A wireless probe?

[Anonymous Custard]

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.

The big question is -

[Anonymous Coward]

Won't that disturb the people who live inside the earth? They may be aliens, but they have rights, too.

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?

Re:Totally ignoring the *real* problem

[Guppy06]

"Liquids are incompressible."

Yes, they are. It's just negligible in most real-world situations. Going miles under molten rock doesn't fall into the "real-world situation" category, though.

But even if this probe were going down in a blob of uncompressable molten unobtanium, Pascal still says that the pressure within the blob is the same as the pressure outside the blob.

"Furthermore, if you made the probe a solid sphere, it'd also be pretty much indestructible."

Ignoring the problem of making sure it really is solid (unless it's truly homogeneous, you're going to have gaps) and the fact that even a solid will compress if exposed to enough pressure, how is it going to produce those "seismic waves" it's supposed to use to communicate to the surface?

"While that may not be terribly useful, it would at least prove you'd be able to send something down there."

How, praytell, will you demonstrate that it really did survive the descent? Go down after it and retrieve it?

Re:Totally ignoring the *real* problem

[Kris_J]

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?

Re:Totally ignoring the *real* problem

[ZanshinWedge]

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 rocks than in the more iron rich mantel or core (which is why Uranium isn't terribly rare in the crust of the Earth).

Also, the probe is only designed to decend down into part of the mantel, not necessarily all the way down to the core.

Re:Totally ignoring the *real* problem

[Guppy06]

"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 why it's so hot down there to begin with.

Um, hello?

[rgoer]

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.

One big problem

[dackroyd]

Won't making a crack this big in the Earths surface let all the gravity out ?

Re:One big problem

[Jerf]

Don't worry, the increased solar radiation from global warming should stuff it all back in.

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.

when professors run out of ideas...

[supernova87a]

they still shouldn't go fishing for research topics at the movie theater!! :)

Great idea. It should work.

[mnmn]

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!

Other 4th Grade Papers...

[$$$$$exyGal]

More 4th Grade Alien Papers

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

And Everyone Thought

[asv108]

Andy Rooney was nuts..

Crack in the World, 1965, Dana Andrews

[jerryasher]

Crack in the World (1965)

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

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"....]

Re:Crack in the World, 1965, Dana Andrews

[Henry V .009]

Where is the weakest area in a crack? The endpoints. So any force directed on the endpoints can lead to catastrophic failure (makes the crack wider).

Now what's the weakest part of a circle?

Re:Crack in the World, 1965, Dana Andrews

[jerryasher]

I seem to recall this being done in cracks in metal and even plastic (?) surfaces on light aircraft. The quickest, best explanation googled for (stress holes reduce) is here.

Their explanation goes to crystalline structures, and stress and loadbearing being a function of surface area. Basically the crack hitting the hole allocates the stress around a much larger unit of area. So the force per area is much smaller than when there is no hole and only a crack. The reduced force per area can then be managed by the material and won't crack further.

Note, the hole must be smoothly finished (you did use the smooth finishing h-bomb and not the rough cut h-bomb) and than there are no more dislocations to start a new crack.

That's my laymen's understanding.

Pretty neat though, the final scene with two moons. THIS MOVIE SCARED THE HELL OUT OF ME!

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.

Sounds like...

[Winterblink]

... the opening scenes of a Jerry Bruckheimer film.

Data? What data?

[Steve B]

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?

Re:It'll never work...

[phyrestang]

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. So does that mean they float at night?

Actually discussing proposition

[lommer]

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!

Re:Data? What data?

[Parsec]

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.

Ob. Bob the Angry Flower Reference

[Fesh]

Oh boy, you sure asked for it...

A little cartoon entitled "Yes"...

Offtopic? Maybe. Graphically humorous? Hell yeah.

Dubious

[mongbot]

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?