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

You can...

[Anonymous Coward]

... eat my nuts!

This is a lame first post (attempt). I almost hope it does not make it.

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

[phyrestang]

At least wait until the Earth becomes a Class I Civilization, or even approaching a Class II Civilization (If we ever make it that far) before taking on something like this.

Didn't anyone see The Core?

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

[MikeFM]

No. Was The Core any good? It looked kind of sucky but that was just my first impression. :)

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

[phyrestang]

As far as Hollywood entertainment goes it wasn't too bad. But it had some reality issues I just couldn't get past. For example: Operating a plasma torch using the output from one of the crew members breathing tank in place of an oxygen tank.

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 :)

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

[Maserati]

Meh. Rent it on DVD. You know how they say about big-budget films, "you can see it all on the screen" ? Well, you can't. Seriously, it looks waaaaaaaaaaaaaaay cheap.

Expect cheesy and you'll be fine. Have some beers handy and be prepared to laugh at spots that weren't supposed to be funny. You know the drill.

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

[MikeFM]

I don't rent anything I don't want to spend the hdd space to rip. If it isn't worth the $5 (at $1/gig) of hdd space and the $1 rental fee then why bother. :)

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

[Anonymous Coward]

Remember, dreams always lead to hideous implosions.

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

[Anonymous Coward]

Holy crap, I hope you're joking.

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

[Jeeza]

And be sure to ask your parents first !

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

[skia]

Or you could, you know, just drop it in a volcano or something.

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

[Anonymous Coward]

Your argument is tantamount to the early arguments that a nuclear explosion would ignite the atmosphere. There's a small possiblity that some fusion would occur in surrounding water due to the shock wave from the explosion (heat and pressure + neutron flux); but, heat, pressure and radiation flux fall off as r^-2; so, there are natural limits on how far the effect could occur.

There's no reason (physics and engineering) which would limit the maximum size of a nuclear weapon. The sun is a naturally occuring, self-sustaining nuclear explosion...

The real reason for limiting the size of bombs is the insanity of it (if there is ANY sanity to using nuclear weapons) -- a bomb of 100 - 150 MTons would yeild a crater approaching 10 miles with an area destroyed by the blast in the 100's of miles radius. That hasn't begun to factor in the area affected by direct and indirect (fallout) radiation.

Why would you ever need anything even that big?

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

[Anonymous Coward]

Wouldn't work. It would have to be an actively erupting volcano to begin with (Hawaii maybe?). A volcano is an upwelling of magma due to pressure. The pressure and flow would just carry the probe back out of the volcano. Try forcing anything into a waterhose while the spigot's on. Now imagine trying to just drop it in...

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

[nomel]

Why not just use a fairly dormant valcanoe. You could probably access the molten by drilling a fairly small hole. And you wouldn't have the upwards moving magma that would rule out an active valcanoe.

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

[Anonymous Coward]

Why not just use a fairly dormant valcanoe. You could probably access the molten by drilling a fairly small hole. And you wouldn't have the upwards moving magma that would rule out an active valcanoe.

I'm not a geologist, but I would suspect that disrupting the plug/cap of a dormant volcano [note the spelling] might cause it to become somewhat less dormant.

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

[Anonymous Coward]

val canoe - a Viking canoe?

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

[p3d0]

Yep. Too bad the Earth is a two-dimensional circle. If it had been a three-dimensional sphere, then a single hole through the middle wouldn't have split it in two.

Blockbuster Busts: Come True!

[Metallic Matty]

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..

Re:Blockbuster Busts: Come True!

[tomakaan]

You forget the lack of space! It's there. You just wait and see.

Re:Blockbuster Busts: Come True!

[l810c]

- 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.

Dr. Evil Suggestion?

[Anonymous Coward]

Then after this they might come up with a "la-ser" and a "tractor beam"

Re:Dr. Evil Suggestion?

[Anonymous Coward]

Ok, people. The first couple of times it was "fun-ny". But please cut the frickin "Dr. Evil" jokes.

Re:Dr. Evil Suggestion?

[Anonymous Coward]

But Scott, daddy loves you!

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.

[XenonDif]

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. :-) Oh, I get it.. He's trying to get into grad school.

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.

X Prize will fall to the Earth's surface.

[Anonymous Coward]

http://www.cbc.ca/stories/2003/05/13/x_prize030513

Big iron hole in the ground.

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....

[XenonDif]

It's easy enough to make the shell out of something that won't disolve in the iron. You could just make it out of bricks. The hard part is making the insides out of something that not only won't melt, but WORK at those temperatures. because you won't be able to keep the heat out forever. This rules out most electronics, including copper and aluminum wire. You could try actively cooling the inside with a thermoelectric devices. Don't know if those will still work at these temps tho.

Re:There's the problem....

[Dyolf Knip]

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. You'd need some kind of trailing superconducting radiator wire and an entire ocean for a heat sink to empty it into (don't plan on having that ocean after this is over with). _Maybe_ then you could keep the inside of your probe cool enough to operate.

Re:There's the problem....

[Anonymous Coward]

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.

I guess this means electricity is out of the question.. oh wait.

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....

[XenonDif]

It would be a lot more efficient if you had a big cold heat sink but hey, we're packin' nukes. You only need to pump the heat back out to the outside (or at least an intermediate layer,) at the same rate as it wants to diffuse in. It would warm out the outside case slighly hotter than the molten iron, which would carry away the excess heat. I like the refrigerator anology.

Re:There's the problem....

[XenonDif]

I like that. Encase a refrigerator in brick and toss it into a volcano. Keep development costs down. Just need a REALLY LONG extension cord.

Re:There's the problem....

[Captain Nitpick]

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.

Won't work.

Heat only flows from hot to cold. Refrigerators work by making the exterior heat exchanger warmer than room air, by compressing the refrigerant.

Let's assume the refrigerator is inside the insulator so it won't melt. The refrigerator must also necessarily generate thermal energy during their operation. 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. 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. And it melts faster than if there had been no refrigerator at all.

If we assume the refrigerator is outside the insulator (as in a normal kitchen refrigerator), then it must be built to operate above the temperature of molten iron. And if you can do that, why not just build the whole probe the same way?

Molten iron is a good conductor of heat, so convection would carry the heat away from the probe.

ITYM conduction. Convection requires a fluid, which molten iron barely qualifies as.

Re:There's the problem....

[UniverseIsADoughnut]

"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

Re:There's the problem....

[kinnell]

Convection requires a fluid, which molten iron barely qualifies as

If molten iron is not a fluid, why do we call it molten? I imagine at the kind of temperatures at the centre of the Earth, molten iron would have very little viscosity, and would convect quite nicely. Of course this doesn't invalidate any of the other points you make ;-)

Re:There's the problem....

[Captain Nitpick]

If molten iron is not a fluid, why do we call it molten?

I didn't mean to imply that it wasn't fluid, only that it wouldn't flow well enough to convect heat away from a probe.

I imagine at the kind of temperatures at the centre of the Earth, molten iron would have very little viscosity, and would convect quite nicely.

You forgot about the incredible pressure, which generally tends to cause materials to solidify.

I don't know terribly much about the properties of molten iron, so I assumed that at mantle temperatures and pressures (remember, this thing has to survive the mantle to get anywhere near the core), it wouldn't flow terribly well. That's what I get for assuming something that I should have checked. So, time for digging.

A five-year-old Nature article pulled from Google's cache says that it is believed that the outer core is mostly liquid iron. It further states that the viscosity estimates vary by 12 orders of magnitude.

However, it also says that a first principles simulation says that iron would have very low viscocity at the core. Since the "Big Blob of Iron" is experiencing the same conditions, it should behave similarly (assuming the core actually is iron).

However, I still don't have any info on the enormous region from the bottom of the lithosphere all the way down to the core.

Not that this matters. You'd have to build an unmeltable refrigeration unit for it to make any difference.

Re:There's the problem....

[ehiris]

Yeah we could use heat resistant foam ... Oh wait ...

Re:There's the problem....

[kinnell]

a first principles simulation says that iron would have very low viscocity at the core

Then I shall eat my hat. I suppose that with iron being such a good conductor, any convection effects would probably be irrelevant in any case.

You'd have to build an unmeltable refrigeration unit for it to make any difference

An unobtanium vacuum flask might do the trick.

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....

[shogun]

I like that. Encase a refrigerator in brick and toss it into a volcano. Keep development costs down. Just need a REALLY LONG extension cord.

Nah make it even simpler, use a geothermally powered refrigerator and then you don't even need the extension cord.

Re:There's the problem....

[CableModemSniper]

Quick everybody this sounds like the new "beowulf cluster"...Yes, but imagine it in a brick refrigerator!

Re:There's the problem....

[Dyolf Knip]

Ah, so you want one-way insulation. Heat flows easily from the probe to the iron, but not the other way. Does such a thing exist?

Re:There's the problem....

[192939495969798999]

Yeah, unobtanium dioxide!

Re:There's the problem....

[stanmann]

I think you just described a peltier.

Re:There's the problem....

[jhylkema]

Terribly sorry, I cannot resist.

1. Build a Beowulf cluster of geothermally-powered brick-encased referigerators in Soviet Russia.

2. Chuck 'em into a pool of molten iron.

3. Journey to the center of the Earth.

4. ???

5. Profit!

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.

Re:There's the problem....

[WolfWithoutAClause]

Yes, I want that, no it doesn't exist. And no, I don't need it to ensure that the inside of a refrigerator is cooler than it's surroundings, whether the refrigerator is surrounded by molten iron or gaseous air; it makes no difference.

Admittedly the practical difficulties of the molten iron case are harder, but the maths is very much the same. If your kitchen refrigerator works, then so does one surrounded by molten iron, if designed correctly.

Re:There's the problem....

[Captain Nitpick]

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.

That paragraph assumed the refrigerator (read: the compressor, because obviously one heat exchanger has to be outside, and the other inside) is inside the insulator. You've got the probe at X degrees, and because it's in operation, the refrigerator is at X+N, where N depends on the efficiency of the refrigerator. Because it is inside the insulator, and presumably operating at a lower temperature than molten iron, the heat flows into the probe, not the iron. Now you have the heat from the iron and the refrigerator going into the probe, and the heat transferred by the refrigerator going out.

No. The infinite series converges to a finite value, because the fraction of heat pumped is larger than the waste heat generated.

You know, you're right about that, but you should have quit while you were ahead. You make a real doozy of a mistake in the next two sentences.

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.

You only have two thermal reserviors, the iron, and the probe. By allowing the transfer of X watts of heat from the iron to the probe, you can generate N <= X watts of usable energy. With that N watts of usable energy, you can transfer Y <= N watts of heat out of the probe. Y <= X. At 100% efficiency, the most heat you can transfer out is the heat you let in to generate the power in the first place. You cannot use heat flowing naturally from A->B to actively transfer a greater amount of heat from B->A. If that were possible, AC units would be self-powering.

Let me guess, you're not real strong on thermodynamics?

I may not be strong in it, but at least I didn't just propose a perpetual motion device.

Re:There's the problem....

[Anonymous Coward]

...and I feel compelled to point out that the mantle is solid rock, not liquid.

Re:There's the problem....

[Rich0]

This treatment is correct. To generate power you need a heat sink and a cold sink. To run a powered air conditioner you need a copule of things the heat sink used to generate the power needs to have a greater temperature difference from its associated cold sink than the object to be cooled does relative to its surroundings.

In your refrigerator example you want to keep a soda at 4C compared to a room at 25C. To do this you hook it up to a power line which runs to a power plant which has a blazing furnace at one size and river water at the other (more thant a 21C difference).

You can actually put most of the refrigeration unit inside the insulator contrary to some posts here. Only the heat exchanger needs be outside - so the mechanical problems are not QUITE as bad as suggested. Many home A/C systems have a heat exchanger inside the house, a compressor inside the house, and the compressed freon runs out an insulated pipe to the outside where it releases heat. Of course, I'm not quite sure what kind of cooling system uses refrigerants which work in the thousands-of-degrees range.

Re:There's the problem....

[WolfWithoutAClause]

To run a powered air conditioner you need a copule of things the heat sink used to generate the power needs to have a greater temperature difference from its associated cold sink than the object to be cooled does relative to its surroundings.

Good posting. However, that last point seems dubious, unless I've missed something stupid, but I don't think so.

If I had a 1 degree temperature difference on my hot sink, but a 50 degree temperature difference on my refrigerated section, I can still run the refrigerator to maintain the 50 degree difference if I allow a lot of heat flow to go between the hot sink and the cold sink, enough to run the refrigerator to maintain 50 degrees. You'll get really rotten efficiency with the generator section, but it works fine.

Re:There's the problem....

[WolfWithoutAClause]

You only have two thermal reserviors, the iron, and the probe. By allowing the transfer of X watts of heat from the iron to the probe, you can generate N <= X watts of usable energy.

No, you big dope. You don't generate energy by letting heat into the probe! You're right that's dumb, but I never suggested you do that.

You can generate energy by generating a hot reservoir above the external molten iron temperature and then running a heat engine between it and the outside, and then take the energy from that and run the refrigerator.

With that N watts of usable energy, you can transfer Y <= N watts of heat out of the probe. Y <= X. At 100% efficiency, the most heat you can transfer out is the heat you let in to generate the power in the first place. You cannot use heat flowing naturally from A->B to actively transfer a greater amount of heat from B->A. If that were possible, AC units would be self-powering.

Yeah, yeah. Trivial...

Re:There's the problem....

[Captain Nitpick]

No, you big dope.

Didn't they teach you not to call people names when you were a child? That's the second ad hominem you've thrown at me.

You're right that's dumb, but I never suggested you do that.

If you don't want people to misinterpret what you say, you should be more specific.

You can generate energy by generating a hot reservoir above the external molten iron temperature and then running a heat engine between it and the outside, and then take the energy from that and run the refrigerator.

In which case you have to maintain a temperature that is significantly higher than molten iron in close proximity to the probe. This will require a bigger refrigeration unit and more effective insulation to deal with the increased heat transfer into the probe. It will also require a large source of power. This is not impossible.

It is however, a bad idea.

In order to get enough power from the transfer of heat from your hotter-than-molten-iron reservoir to the molten iron to power the refrigerator, you're going to need either a huge amount of whatever it is (and an enormous generation system), or it's going to have to be much hotter than molten iron (requiring even more insulation and a bigger refrigerator). And it's going to have to maintain that temperature difference even though the iron is attempting to cancel it out through conduction, requiring an even larger power source. And again, your system would have to be able to operate above the temperature of molten iron.

Your system may not be forbidden, but it certainly isn't very practical.

(And I completely forgot to mention that you're going to have a hard time coming up with a refrigerant that is still compressible at 20 GPa.)

Re:There's the problem....

[Anonymous Coward]

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

Well...thats easy then

Someone I knew once worked on building semiconductor chips based on slilicon carbide. They worked fine -- just had to get them up to something like 2000 degrees celsius before they'd start working.

Think that might work?

Re:There's the problem....

[Rich0]

I was mistaken - you are correct. The 2nd law of thermodynamics requires that more heat must flow on the generation side than on the refrigeration side, but it doesn't say what the gradient has to be. You are also correct that efficiency is a function of the temperature difference, so a 1C temperature difference is going to require a REALLY BIG generator.

This is basically the difference between a nuclear power plant and a tide-powered plant. The one has a huge temperature difference in a relative small plant. The other doesn't have as big a potential energy drop and consequently you end up having to cover half your coastline with generators to generate power, though in the end you could get just as much.

Re:There's the problem....

[Anonymous Coward]

What P{roblem? I havedeveloped a substance, MacClurite, that will not only survive the immense heat and pressure at the earths' core, but will allow you to fend off Nazi U-Boats and meet incredibly large breasted women. Email me for details on where to send the $50 billion.

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

[Anonymous Coward]

Just a thought, having equal amounts of mass all around you.. if you were to stop right in the middle of the earth, would this cause you to be weightless? or suspended in mid air (assuming the middle of the earth, in this thought, is a large round room) ?

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

[Scaebor]

now if the chinese dropped a probe of their own down to the core we'd be all set! Of course, what we really need is a big zero-gravity theme park located directly at the core of the earth. unfortunately the cost to get in would be a bit expensive what with all the air conditioning costs and all...

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

[stefanlasiewski]

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!

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

[LiquidCoooled]

i dont think you would have much time to be thinking about the pretty weightless "sweetspot" since you would most likely have fried in the dense molten iron long before you reached there.

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

[Anonymous Coward]

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

That joke was more complicated than a Chinese firedrill!

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

[obi]

what about making holes on either side and aiming/aligning them properly? :)

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

[Anonymous Coward]

valid point, but what lets say its all roses in the center and you are alive? :)

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

[Anonymous Coward]

I think it's easier to be weightless in space.

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

[mattwolfewvu]

That, and if you live in the US, you'd end up making a visit to Austrailia, not China.

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

[Anonymous Coward]

Not to be picky, but the other side of the world, for those of us living in the U.S., lies off the west coast of Australia, not in China.

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

[Anonymous Coward]

Assuming a frictionless tunnel (we've given up all hope of a practical discussion here, right?), your momentum wouldn't be an issue. As you fell, your change in "sideways" momentum would always be normal to the tunnel wall (assuming a straight tunnel), meaning that your acceleration in the axial direction would be affected only by gravity. Thus, we can ignore the pesky change in sideways momentum.

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

[Eskarel]

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.

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

[Nucleon500]

Yes, you'd be weightless. Oddly enough, you wouldn't even be mildly attracted to the walls: inside a uniform spherical shell, the gravity always cancels out.

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

[oaf357]

Chunnel... they did it there. It would just have to be on a much grander scale.

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

[GigsVT]

Yeah, just imagine if all those long flights from the north pole to the south pole were eliminated!

Seriously though, it's only useful if it's two places that people want to go. :)

Assuming we could build a stable tunnel through the earth, imagine this, we could come up with a system to capture the lateral energy, think something like a huge piezo crystal that would generate tons of voltage as it was crushed keeping the capsule on track, or something to that effect. Or instead of storing the energy kinetically, and travelling at relativistic speeds near the center of the earth, instead use a huge generator to generate electricity on the way down, and use the power on the way back up. Less efficient, but probably would still use a whole lot less power than flying a jet across the ocean.

I think it all really boils down to a materials science problem. Just need to come up with a material able to wall such an insane tunnel, and the rest is easy. :)

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

[hazem]

I'm not even thinking that the parabola has to go through the center of the earth - I don't think that would be necessary... as long as the line containing the center of the earth and the vertex were perpendicular to the line containing the two end points.

I'm not sure why I feel like a parabola would be necessary, or why it would help. Would it go faster? Or faster with less energy?

Hmmm. I don't have the aparatus to try this, but maybe someone has. Suppose you have to end points, say up on two different tabletops. You then have tracks different tracks that connect the tables, but some go lower than others. While naturally, these tracks would be caternaries, one could probably force them into parabolic shapes (would it matter?). Now suppose I let the Hotwheels(tm) go at one table. Would they both arrive at the other table at the same time?

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

[scotartt]

Estimated temperature earth's inner core = 7300K.

Temperature at Sun's surface (photosphere) = 5800K.

Temperature of Sun's 'atmosphere' (corona) is about 1 to 2 million degrees Kelvin.

Temp. at SUN's core = 8 to 10 millions of degrees Kelvin.

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

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

[Anonymous Coward]

Use two probes: one from China and one from North America

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

[corsec67]

Actually, it is even more simple than that: if the endpoints of the tunnel are the same distance from the center of the earth, then it is POSSIBLE to complete the path, expending no net energy. The path could even go far above ground, just so long as you then reasorb thhat energy on the way back down.

Yes, there is a shape of track such that a car released on that track at any point will take the same time to reach the bottom, and it is pretty close to a circular track, but I don't rember what it is called.

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

[Anonymous Coward]

"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."

Who ever said the hole through the center had to be straight? The Hole I'm jumping in is curved in a direct proportion to my sidways speed. As th center of the earth turns 'faster' from my point of view, the hole at the center is more curved.

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

[scotartt]

No no I meant Sun Microcomputer. We drop one of these probes onto McNeely's brain.

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

[Anonymous Coward]

FYI The period of the motion would be 84 minutes. We had to find it in physics a few months ago

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

[davejenkins]

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 proxmity to the center maximizes gravitational force, and the gravitational pull from the dirt above you (back toward the surface) is minimized. This would be the meximum gravity point. From there to the center, gravitational acceleration would drop off, become xero, then maximize at the other anti-LaGrange point on the other side, then tail off to 1 G at the surface again.

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

[JimPooley]

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

Should have turned left at Albuquerque!

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

[Atsjoo]

Oh, I don't know. They looked pretty darn attractive to me. Maybe a pair of fishnet stockings...

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

[braun]

Consider this: First of all, as pointed, the rotation of earth causes a force called Coriolis' force to act peripendicular (to the right) to the direction of motion. Therefore the probe will not go only downwards, but in a curve, like things thrown off high buildings. Therefore if the probe is set to motion on the upper half of earth, the motion of the probe will be directed more and more towards east (a=wxv). A stone wedgie in your eastward side. The other problem is that of the cooling of the probe: If cooled, the viscous friction will increase, causing the probe to slow down. And, you'll need a quite nasty cooling system to actually make any real difference. And, how 'bout the problem of pushing away all that iron?

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

[Eskarel]

For a second there I was about to question your true geekiness because a true geek wouldn't worry about the fact that the resulting tunnel would be purposeless. Of course then you saved yourself :)

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

[LiquidCoooled]

then yes :)

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

[Anti_Climax]

If we went through the center of the earth in a straight line, why would we be coming back out in the northern hemisphere? I would think this would be of more use getting to Austrailia...

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

[p3d0]

I wonder if there's some "coriolis-friendly" spiral-shaped path through the planet that will allow you to make the trip without jettisoning your rotational velocity? As a bonus, such a path would not need to go through the nasty center of the planet.

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

[Anonymous Coward]

Everything has been done in Science Fiction. See Vernor Vinge's A Deepness in the Sky- he discusses travel along minimum energy paths. The Obejction to that mode of transit is that the energy minimum paths go deep under the surface- several hundred KM.
Not worth it as round trip travel along the surface of the earth can be easily engineered to be zero energy as another poster points out.

Very interesting...

[aeinome]

I can only think of how far the probe would go... I doubt it would go all the way to the centre of the Earth, but still, this looks like an interesting step for geology.
Much like giving the Earth a suppository, really.

Don't forget

[Anonymous Coward]

The "o-zone lay-er"

also at yahoo

[gumbi west]

An article was also posted at yahoo

Fisrt message

[Unregistered]

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.

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

[Anonymous Coward]

Worst. Idea. Ever.

Is that the same thing you said when they recommended that you learn where to put your punctuation marks?

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.

Re:This will never work

[lirkbald]

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.

Re:This will never work

[bpbond]

The author (on NPR today) basically said that himself: no, this won't work exactly as laid out. It's a thought experiment, attempting to get scientists as interested in exploring down (Earth) as up (space).

As for "worst idea ever," well, that just sounds like envy.

Re:This will never work

[Anonymous Coward]

Gee, that's funny. I'm the dean of Washington University. Now get back to work, peon!

Re:This will never work

[jamesh]

and here was me thinking it was a troll.

Re:This will never work

[Anonymous Coward]

Also, if having one far-fetched idea was grounds for revoking tenure, I suspect we'd have very few professors left

Copernicus, Kepler, Newton, and Einstein who?

Re:This will never work

[Anonymous Coward]

someone mod this jackass down.

if you are a professor of earth and planetary sciences, you would know who dave stevenson is. and it would be obvious that he indeed has tenure.

btw, it is "Caltech" NOT "the CalTech".

Re:This will never work

[Anonymous Coward]

The best part is that this guy doesn't even seem to know who Dave Stevenson is. You can love him or hate him, but if you work in Planetary Sciences, you know who he is, and you know he has tenure at CalTech.

Re:This will never work

[Anonymous Coward]

NOT "CalTech"

It is "Caltech"

Get this right people!!!

Re:This will never work

[Anonymous Coward]

what's wrong with "pop science"?

Re:This will never work

[gl4ss]

"'Also, if having one far-fetched idea was grounds for revoking tenure, I suspect we'd have very few professors left'

Copernicus, Kepler, Newton, and Einstein who?"

actually everyone else than those. add hawking to the list too, and perhaps one or two other guys.

Why Bother ?

[Anonymous Coward]

Why the hell would you want to send a probe to the middle of the core ? I mean maybe magma flows near the surface or layers lower down may be of some importance for scientific research, but it would just sit in the core like a useless piece of shit sits on the ground. This is is yet another fantastic idea which will never come into fruition. This is like researching viagra, there are more important things to research !

Re:Why Bother ?

[Taliesan999]

For some reason I misread "layers lower" in the above as "lower laywers" then thought not a bad idea...

Lower lawyers down to probe the Earth's core. Hell, once they hit the molten stuff they'll last all of 5 seconds, but we can keep trying. Eventually we'll run out of lawyers or succeed, either outcome works.

In other news...

[Anonymous Coward]

A new technique is being developed by Islamic extemists for scientific probing. A spokesperson for the Islamic group says that instead of terrorism, they will now be focusing on science to make the world better. Their technique involves activating very active devices that create a "boom" noise and molten metals. It allows them to get a probe into just about anything. They currently are getting contracts with the US government for probing for terrorists. Other things the group is working on is "proving evolution" and "slightly modifying thoughts of people to serve public good." The latter is being sponsered by the Orwell foundation and the Aldous Huxley Orginazation For A Better Tomorrow.

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 ...

Re:Blob of Iron? More like a slashdotted server

[Anonymous Coward]

Clearly, you haven't looked at the pure physics of your proposal. The temperatures reached in a Salshdotted server are far greater than the temperature of liquid iron, and would end up vaporizing the metal. The net effect would be foul gas errupting from your crack, and the probe placed in your crack shooting out.

Re:Blob of Iron? More like a slashdotted server

[Anonymous Coward]

I hate to destroy your romantic notion of the so-called "Slashdot Effect", but servers don't actually melt down or get physically damaged during one. During the so-called, "Slashdot Effect", the number of active visitors to a linked site dramatically increases, often to limits far beyond what the server can simultaneously handle at a given time. Usually the limits are a) number of open sockets, b) number of open DB connections for dynamic content, c) buggy server software which does not stand up too well under load (read: Microsoft products). Sometimes, the network bandwidth itself is simply overtaxed. However, once the usage spike drops, assuming a server reboot is not necessary, the service will be back up.

So, there'll be no expensive servers to replace, and no puddles of melted plastic and molten metals to clean up. In summary, if you just show some patience and attempt to access the site's contents a little later on, I'm sure you will be able to.

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?

Re:Are they sure this will work?

[Anonymous Coward]

But then the probe would be able to continue without the molten metal, wouldn't it?

Re:Are they sure this will work?

[spacecowboy420]

Gravity

Re:Are they sure this will work?

[Anonymous Coward]

Molten rock, strangely enough, is light. Oh, sure, a rock is denser than, say, your average slashdotter. However, pure iron is much denser. Also, similar materials tend to stick to each other. The chemical bonds between rocks and iron are based on different principles. So just like when you take a blob of molasses and drop it in water, it'll tend to stick to itself and drop like a rock... err, blob of molten iron.

Re:Are they sure this will work?

[Anonymous Coward]

Oh, sure, a rock is denser than, say, your average slashdotter.

Brave, brave statement there.

Re:Are they sure this will work?

[Anonymous Coward]

interestingly enough the mantle is NOT molten. the pressure-temperature conditions in the mantle are such that it is a solid with a visco-plastic rheology. solid rock that convects on geologic (hundred million year) timescales.

in fact, the way to get the mantle to melt is by decompressing it adiabatically (the solidus line for mantle rock has a shallower slope in P-T space than an adiabatic P-T trajectory).

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!!"

Re:Why not use cracks already here?

[Anonymous Coward]

even then, if the magma is under such unimaginable pressures that it forces its way up and forms volcanos, then an artificial hole is gunna probably do the same.

Poking an over-inflated balloon with a pin.

Re:Why not use cracks already here?

[Anonymous Coward]

I don't understand your signature. Are you saying Windows does not properly handle mouse and other pointer devices? Sorry, but I've been using Linux since 1993, FreeBSD for the past 2 years, and Windows since version 2.21 (or whatever that version that ran on the Dec PC), and I'm here to tell you, while *nix support for pointing devices is decent _now_, Windows has _always_ been ahead of the game in supporting a huge variety of pointing devices.

So you're full of shit.

Yes...

[Anonymous Coward]

let's keep messing with qauntum this and dark matter that. And quarks and anti matter and drilling big fucking holes in the earths crust. I'm sure we can blow everything up by accident if we try REALLY hard.

Re:Yes...

[pyrrho]

finally, some support! thanks.

Re:Yes...

[spacecowboy420]

Wouldn't you just have to take that chance? I mean, if you take away learning/experiencing new things - what else is there? If you happened to lose your life living it, wouldn't that be better than living your life by trying to keep from dying?

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.

Re:A wireless probe?

[worst_name_ever]

I understand that their backup plan is to use a few thousand miles of molten Cat5...

Re:A wireless probe?

[Anonymous Coward]

but I still can't get my cellphone to work in the subway.

But if you got it working down there, all you'd have to talk about is: "Hello??? I'm on the TRAIN! Yes, I know... Uh huh... Can't this wait until I get home?"

Re:A wireless probe?

[sholden]

Maybe if your phone had an antenna 5 miles long, and 4 foot wide...

Oh and the high powered laser beams bouncing back and forth inside:)

Re:A wireless probe?

[eglamkowski]

The message the probe will be sending back:

"Can you hear me know?"

It'll never work...

[Anita Coney]

Everyone with a brain knows that the Earth is hollow! http://www.v-j-enterprises.com/holearth.html

Re:It'll never work...

[zapp]

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.

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?

Re:It'll never work...

[Anonymous Coward]

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?

Ah HA! So that's how they managed to do it in those childrens' books!

Re:It'll never work...

[Anonymous Coward]

Perhaps you could begin here.

Re:It'll never work...

[phyrestang]

And the cow jumped over the moon
Yup, that's how they did it.

Re:It'll never work...

[Anita Coney]

I've always suspected that about cows, that's for offering some proof!

Seriously, though, I don't believe it. I just brought it up because my dad owned an original copy of Bernard's "The Hollow Earth." I used to read it all the time as a kid, but even then I thought it was utterly absurd.

Fark beats /. ?

[Anonymous Coward]

Kinda sad when Fark beats /. to a geek story of this magnitude.

communicate to probe

[XenonDif]

How does one get data back from said probe? You'd have to transmit signals through thousands of miles of moten metal. I don't think you could use 802.11 for this.

Im sorry, did i mention

[Anonymous Coward]

"we had a blast back in my day lemme tell yah"

Chopping a log

[LiquidCoooled]

I just cant get the picture of using an axe to chop wood out of my head - and imagining the split growing and breaking the earth cleanly in half.

The look on the scientists eyes would be a classic as he realised just what he had done...

Re:Chopping a log

[jamesots]

I just cant get the picture of using an axe to chop wood out of my head

I can't get the picture of you chopping wood out of your head out of my head.

Re:Chopping a log

[PhuCknuT]

Yeah only with the scale of the earth and the probe it would be more like sticking a microscopic needle into a redwood tree, the chance of it splitting is near enough to 0 that it can be ignored.

Re:Chopping a log

[Anonymous Coward]

spoilsport :P

Gee

[Anonymous Coward]

What an informative post!

No mention of why it won't work, just some credentials and a declaration.

+1 Informasightful!

Re:Gee

[Muhammar]

Fugettabout iron, this will be another good use for Depleted Uranium. DU penetrator will sink even better than the Earth and Planetary WU authority.

Oh, and using not-so depleted uranium, we could start a chain reaction in the stuff and the liberated incidental antineutrino pulses could be picked up by the existing neutrino detectores, as they have been doing with nuclear reactors already. No need for the proposed gravitational dectector signalling. All we need for this is the entire mass of Iraq uranium (and teaching the probe how to use the Morse code).

Re:Gee

[The_Unforgiven]

You couldn't take the time to log in before giving such great things, either?

Re:Gee

[Anonymous Coward]

I doubt there's enough depleted uranium to do the job. Iron has the virtue of being cheap and plentiful.

Re:Gee

[Anonymous Coward]

There are more than 5000 nuclear bombs in the world. Also nuclear ful has to be enriched.

Do the figures; there is an enormous amount of DU in the world, moreover it is looking for a good use.

Dr Who was involved in such a project

[hamoi]

http://www.dwguide.demon.co.uk/ddd.htm

The Inferno is a project designed to tap the molten core of the
Earth, but the drilling threatens to unleash vast unforeseen forces
instead, foreshadowed by a dangerous mutative green slime, and
actually seen by the Doctor when the inoperative TARDIS console
slips him sideways into a parallel Earth where England is ruled
by an oppressive fascist military state.

Re:Dr Who was involved in such a project

[Anonymous Coward]

That was one of my favorite episodes, too, man

Re:Dr Who was involved in such a project

[Anonymous Coward]

The parallel Earth that we live in is nothing like that, of course.

Here, it's the U.S.A. that's ruled by an oppressive fascist military state.

umm... yeah

[cr@ckwhore]

Something tells me that FSCKING WITH THE EARTH'S CORE IS NOT A GREAT IDEA! HOLY FUCKING SHIT.

Anyone else get the same vibe, or am I alone on this one? derp.

The Hole Will Close Back Up...

[$$$$$exyGal]

This though experiment also assumes that the hole doesn't just close back up within 50 milliseconds. Even if this probe were to continue burrowing downwards, after it hit several miles down, I imagine that the empty space above it would simply fill back in.

This is especially true if the probe just "burns" through whatever is beneath it. Even though the probe is passing through the "burnt" earth, that doesn't mean the burnt earth doesn't just re-solidify after the probe passes through it.

Re:The Hole Will Close Back Up...

[Dyolf Knip]

That's cool, the probe would be communicating back up via tectonic/gravitic means. Rock in the way actually makes things easier.

Re:The Hole Will Close Back Up...

[Anonymous Coward]

Well of course the hole would close back up. The upper mantle is plastic (it oozes), the lower mantle is liquid rock, and the outer core is liquid metal. Saying that the hole would close up is about as interesting as saying a hole in water closes up. I'm sure he already thought of that, and mentioned seismic communication as a solution.

Incidentally, the idea of using something like LIGOS to detect the vibrations is pretty stupid, IMO. LIGOS is for detecting gravity waves, which have almost nothing in common with seismic waves, except for the fact that they're both waves. Seismic waves are just sound waves traveling through rock, while gravity waves are stranger, being induced by the motion of mass like electromagnetic waves are induced by the motion of charge. Seismic waves are much easier to detect.

As for electronics, I could conceive that the probe might be able to operate if it were either (1) large enough or (2) operated mechanically. I don't think too much thought has been given to making high temperature electronics, but you could certainly build a mechanical device out of the mythical material you're building the probe out of.

Re:The Hole Will Close Back Up...

[Anonymous Coward]

My comment was in response to its parent post. That parent post was theorizing how you could jump down into the resulting hole left by this probe.

Comment removed

[account_deleted]

Comment removed based on user account deletion

Hmmmm

[Anonymous Coward]

"Mom, Dad, Why is the ground shaking" as hundreds of low-trained government officials speed by at 110mph in hum-v's screaming bloody murder.

A few seconds later the ground stops shaking.... Than a violent explosion is heard."

Jimmy and his family were never seen again, and the government covered it up by saying a new volcano was forming.

Need we see mistakes our lovely government has made before, to know that this will have to be attempted approx 100 times over the course of our natural lives and our kids natural lives, than we realize.. "Hey, tectonic plates move..!" when we continue drilling.

Egh...

I'd love to see it if it works.. lol

--W

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.

Re:The big question is -

[Anonymous Coward]

I hate to argue this, because I know it was a joke... but if they are in the center of the earth, they aren't aliens. They're Natives

Re:The big question is -

[kiwaiti]

you are quite wrong - WE are inside

Kiwaiti

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

[Anonymous Coward]

Liquids are incompressible. Furthermore, if you made the probe a solid sphere, it'd also be pretty much indestructible. While that may not be terribly useful, it would at least prove you'd be able to send something down there.

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

[polymath69]

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 below that. (Does anybody know at what depth the pressure starts to decrease?)

Still, I'd guess the pressure at that maximum point would be quite high, and probably not sustainable with current materials and engineering.

Re:Totally ignoring the *real* problem

[Anonymous Coward]

no!

plutonium is a synthetic element.

uranium is quite rare and is concentrated in the earth's crust. the reason is that uranium is highly incompatible and remained in the leftover, high silica "scum" that formed the crust back when the planet was undergoing differentiation (first 100 million years after formation).

the core of the earth is made of iron for a reason: it is the most common, dense element making up the earth. back when the earth was differentiating and was partially molten, most of the iron sank to the center of the planet to form the core (due to density contrasts). in fact, so much gravitational potential energy was released by this "iron catastrophe" that the entire upper mantle and crust melted!

generally speaking, the mantle is made of olivine. this is a silicate mineral containing magnesium and iron: (Mg,Fe)2SiO4. pressure increases with depth. however, the mantle composition is uniform. the effect pressure does have is the crystalline structure of olivine. so as depth/pressure increases, the crystal structure becomes more closely packed: olivine -> spinel beta structure -> perovskite. perovsike structured olivine, while dense, is still not as dense as metallic elemental iron at the core.

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

[Anonymous Coward]

>pressure at the center is exactly zero

this, i assure you, is patently false

Re:Totally ignoring the *real* problem

[Anonymous Coward]

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

Pressure is exactly zero only in absolute vacuum.
You must be confusing it with weight.

Re:Totally ignoring the *real* problem

[simong_oz]

Liquids are incompressible.

no they're not - if they were incompresssible they could never be pressurised. It's why they're so useful in hydraulics. You can generate a high pressure by compressing the liquid by only a very small amount and that pressure is almost instantly transferred to all parts attached to the system. Lubrication also works precisely because liquids are compressible (that's simplifying it, but let's go with it for now).

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

That is also wrong - solids are also compressible, though in every day circumstances the pressures are never anywhere near high enough for this to be of any concern. However, when you're talking about the pressures at the centre of the earth, I'm pretty sure you've gone out of the realms of "every day circumstances".

I have to admit, it would be a very intriguing and interesting design problem.

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.

Re:Totally ignoring the *real* problem

[Anonymous Coward]

IAAME (I am a mechanical engineer) furthermore, I have experience in designing both high temperature and high pressure equipment. Mostly in downhole completion equipment (read: the oil well stuff that goes underground). I speak from experience that the greatest current limitation on well depth is temperature. Desinging and manufacturing a deivice that can operate in molten iron for any useful amount of time is NON-TRIVIAL.

High pressure is easy. Just make it thicker. But if it does not have any measureable strength at 2800degF, I don't care how thick it is, it won't work. This is ignoring how thermal expansion will affect any sort of seals the shell might have. Speaking of seals, what will they be made out of? I suppose you could weld it (if metal) or mortar it (if ceramic), except most Xtreme alloys are not weldable and the mortar would have to not leak at these high temperatures and pressures. And thats just the problem with the "shell".

Suppose you solve all the shell issues. What are the sensors going to be made of? I can assure you, they will not be electronic. How do you communicate your signals back to the surface?

Old SciFi movie...

[Nick Driver]

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.

Re:Old SciFi movie...

[GMontag]

Do you mean the documentry Crack in the World?

Re:Old SciFi movie...

[biobogonics]

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

"Crack in the World", 1965 see

http://us.imdb.com/Title?0059065

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.

IIRC, at the end of the movie, the crack circles back on itself and forms a plug which when ejected relieves the building pressure and sends a new moon into orbit.

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.

Melting isn't the problem

[Anonymous Coward]

It's the dinosaurs.

Why not just drill instead of NUKE ?

[zymano]

Just drill near a volcanic area. Maybe use a laser . Regular method of drilling would work.

A better reason to drill into the earth is for energy !

Re:Why not just drill instead of NUKE ?

[Anonymous Coward]

Only if you're Duke...Nuker

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.

Re:One big problem

[aaaurgh]

Nah, but it will all run to the bottom.

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:Geek courtesy

[r4lv3k]

Mod parent -1, Troll. If a site can't take the traffic, that's not Slashdot's responsibility. Don't like it? Shut off port 80 and quit yer whinin! r4lv3k

Re:Geek courtesy

[r4lv3k]

That is, Offtopic Troll beeyatch! :)

Re:Geek courtesy

[Anonymous Coward]

No, it is /.'s problem. They know full well that most servers cannot handle the load and they nonetheless provide direct links to the sites which soon collapse. Where is the social responsibility? Funny how you guys riot if anybody does the slightest ill thing to Linux however it is perfectly acceptable to effectively pound servers into submission, supposedly in the name of nerds. Funny, I thought it was the business folk that were labeled the unethical ones.

Re:Geek courtesy

[SpaceCadetTrav]

Yes, Slashdot can serve out large dynamic pages to tens of thousands of people for each article they post, but they can't afford the bandwidth for that single page that they link to, which is only viewed by about one third of the Slashdotters even when availability isn't a problem. Nice conspiracy theory, idiot.

Re:Geek courtesy

[lpret]

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.

Needless to say, I think this is a problem, but I still have not heard of a decent solution. The best so far is a Google cache. But perhaps a Peer2Peer system could work in this situation. Have logged in users who are able to get to the site in time share their cache with other users. I don't know about the technicalities, it's an idea. Maybe it'd be a thing where if you did it, you'd get the same benefits as a subscriber. Ideas for the weary.

Re:Geek courtesy

[Anonymous Coward]

Not that this makes your complaint invalid in the general case, but as an alum of said institution, Caltech web sites - especially those it's hoping will garner a lot of publicity - should be trusted to keep up with just about any semi-reasonable amount of traffic; they do with some frequency deal with being linked to by places like cnn, msnbc, the ny times, etc. There are not a few clever kids there, and trust me, plenty of computational resources.

Easy

[Anonymous Coward]

This is easy, just go to Mt. Sneffels in Iceland.

when professors run out of ideas...

[supernova87a]

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

Mental Exercise

[linuxwrangler]

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.

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!

Re:Great idea. It should work.

[Guppy06]

"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.

Re:Great idea. It should work.

[rgbe]

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.

A cooling system requires a cool reservoir which is usually outside the system being cooled. This is so that the heat can escape from the part you want to keep cool. The problem is that even the best cooling system won't work to keep electronics cool for long periods.

But why use electronics? How about some kind of fluid/mechanical mechanism that "thumps" on a regular basis depending on the surrounding temperature (for a temperature probe). When it's hot it does more "thumping" than when it's cold. But I don't know how happy the LIGO people would be with continuous "thumps", don't their experiments require absolute silence?

I wonder if lead would do, or should we try Uranium.

I know lead will melt, I think uranium will too. But who want's to send uranium down one hole, when I might be spat out another hole (such as a volcanic erruption) a few years later, and create a large radiactive mess.

I've had an idea like this a few years back; it was a little flawed, because of my very last point. Drill a hole through the Earth's crust and drop nuclear waste down it (uranium and plutonium), it will just sink to the core, which is already a huge radiactive soup, the radiactive soup is the fire which keeps the silicon (or whatever magma may be composed of) molten.

And finally the idea that most of the space under the crust is molten mantle is still just a theory.

But it's a pretty sound theory too!

Psi

Re:Great idea. It should work.

[flyhmstr]

Given there will be nowhere to dump the heat from the probe (it being surrounded by molton iron and falling into the center of the earth and therefore into a hot environment) a better approach would probably be to design the probe to work effectively at the sort of temperatures it's likely to encounter without relying on a cooling system (which is yet another thing to break anyway).

Re:Great idea. It should work.

[mnmn]

Hawaii is really a network of underground lava streams that come out of the cracks, or rather seeps out. Should the hole be big enough, we'd have a fountain like we have close to some unfortunate villages.

An easier idea might be the deep sea abyss, but heating iron there is tough without nuclear weapons.

Re:Great idea. It should work.

[mnmn]

Modern electronics rely on fibreglass boards, solder,silicon and ceramics. We could lose the solder and fibreglass, and change the ceramics I guess but circuits work badly under a lot of heat... most metals start losing their conductivity at higher temps, so more research. I doubt detectors would work too hot, certainly not infrared piles. Thermometers can work hot.

Most communications and detection would be done with radio waves I think. This also means there should be a way to transmit through all the iron, else use something else that allows radio waves through.

Re:Great idea. It should work.

[barakn]

You didn't read the proposal very carefully. The difference in density between the molten iron and the rock it passes through is so great that the iron itself causes the crack. It would never pool up and dissipate horizontally. It just keeps sinking down in its own self-formed, self-healing crack.

Re:Great idea. It should work.

[doublem]

Heck we could even send bombs to China.

If we destroyed China, who would manufacture all our sports clothing and inexpensive crap with slave labor?

Rule #3 for use when evaluating proposals

[Anonymous Coward]

Rule #3 states that the use of forumlae is inversely proportional to the sensibility of the proposal and directly proportional to the degree of obfuscation intended by the author.

The crux of this proposal is that we start by finding a crack in the crust, blow it further open with a few million tons of high explosives, dump something over one hundred thousand tons of molten iron into the enlarged crack, and then watch happily as the molten iron melts its way down to the planetary core in a few days.

Without being ungracious to the author, I suggest that he underestimates the quantity of molten iron required by one or two orders of magnitude and the amount of time required for the melt to the core by another order or two of magnitude. On the other hand, he may be reasonably close to the amount of explosives required.

Now that we have unfettered access to some nice, barren land in the Middle East and practically unlimited fuel to melt the iron and evidently no regard whatsoever for the wishes of the nearby inhabitants, I say "let's do it!".

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."

Almost like a non-plan

[Anonymous Coward]

The diagram of the probe going to the center of the earth looks like something I might have drawn on a napkin after a night of heavy drinking. Did any thought at all go into this? I especially like the term "propogating crack".

Old news.

[GMontag]

My word, this has been tried before! Well, maybe they saw the same 1965 documentry that I saw and decided against thermonuclear weapons for diggig the hole, but still, same idea.

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

[Anonymous Coward]

I have to say ( if this is the picture I'm thinking of ) that this was an inspired movie. The best bit was their strategy for stopping the crack - detonating *another* h-bomb to blow a circular hole out of the crust. The rationale that the crack, hitting the hole would then stop. ( They demonstrate with a piece of paper with a circle cut out of it. I think I've seen similar holes stamped out of metal objects. )

Can any engineers in the audience explain to me how this trick works? I have an... intuitive grasp of it, but I don't understand the specifics.

Yours, YLFI.

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!

Re:Crack in the World, 1965, Dana Andrews

[jerryasher]

You can sometimes see this in cracks in car windows. The crack will travel until it hits a pit and then stop. Or it will travel from pit to pit.

Re:Crack in the World, 1965, Dana Andrews

[Bohnanza]

That movie scared the sht out of me as a child. Thanks for bringing it back.

Re:Crack in the World, 1965, Dana Andrews

[Anonymous Coward]

Now what's the weakest part of a circle?

One of the slight irregularities around the circumference will be weaker than all the others. The crack will repropogate from there, most likely (unless some force pushes harder on one of the others).

I cannot believe I am arguing about a 60's B movie...

Re:Crack in the World, 1965, Dana Andrews

[Henry V .009]

Yes, not having a gap is the best of all -- but circles are still better than cracks. Take a piece of paper. Put an incision through one of the sides. Pull the edges apart -- note how it tears. Now, intead of a straight line, cut out a semi-circle from one of the sides. Pull the edges apart. You will notice that it is somewhat stronger.

Re:Crack in the World, 1965, Dana Andrews

[Hognoxious]

Basically, you get a stress concentration at the end of the crack. A hole reduces the concentration, & the greater the radius, the lower the concentration.

Square holes in planes (comet) & ships (liberty) is a bad idea, as the radius at the corner is very very small.

http://www.ncat.edu/~ccmradm/Dr%20homepage/meen_86 0/Chapter1.pdf

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.

Re:A solution for our nuclear waste?

[Anonymous Coward]

The earth's core is radioactive? The Earth is radioactive! There's a concentration in the core; to be certain...

It's simply too difficult to do this. Not to mention that everytime you want to get rid of some nuclear waste, you have to explode a nuclear bomb...

See the flaw in the logic yet?

sorry for being off-topic, btw

[SuperBanana]

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.

Re:sorry for being off-topic, btw

[Anonymous Coward]

I thought it was a very good post. I'd never realised that the primary reason OSDN won't attempt to mirror is because of the bandwidth usage. But it all seems clear now.

Thanks!

Sounds like...

[Winterblink]

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

Leave my probe out of this, please.

[djupedal]

I just convinced her that a hot probe is a good thing.

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?

testing this idea

[technoCon]

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 worried now

[zakezuke]

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 radiation, not much fall out, but issues with radio active isotopes.

Volcanos are moderatly common place on this planet. Why the hell don't you just use a volcano to dump such a probe, rather then using a nuclear weapon to create one.

I'm not sure how one would penitrate the mantle I mean, a fast moving iron dart doesn't nessicarly seem practical, and generaly seems dangerious. I'd vote for a simple probe of the crust mantle layer first, just for common sence sake. I'd have serious concerns about planatary extension. Not to speak about the issue of affecting the temprature of the planatary core, but current theory sugests that the dinos died as a direct result of a meteor impact. While I don't know for a fact that creating a doorway to the earth's core would cause enough dust in the atmosphere to affect global climate. While I have no clue as to the effect I have this mental of a hole in the earth releasing magma and core material at escape velosity as a direct result of mater being compressed over millions of years.

While my concerns may have no scientific proof what so ever, I really think it's a bad idea for us with present technology to drill a hole in the planet, not when we don't have the ability to move. Try it on a diffrent planet for christ sake, while this means waiting for a more mature space program, I don't think this is a bad idea.

Re:Ok, I'm worried now

[Anonymous Coward]

Ok... i'm no geology expert...

Ya think?

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 Except for raising global background radiation over 10%... Volcanos are moderatly common place on this planet. Why the hell don't you just use a volcano to dump such a probe, rather then using a nuclear weapon to create one. You can't drop something into a hole with pressurized materials coming out and expect it to actually go in. Not to speak about the issue of affecting the temprature of the planatary core, You can't be serious. You expect that ANYTHING we do will affect the temperature of the core of the planet by even .01 degrees? You're lost. Go read some books. but current theory sugests that the dinos died as a direct result of a meteor impact. While I don't know for a fact that creating a doorway to the earth's core would cause enough dust in the atmosphere to affect global climate. Would be less than a volcano. Approaching that of a nuclear airburst. While I have no clue as to the effect I have this mental of a hole in the earth releasing magma and core material at escape velosity as a direct result of mater being compressed over millions of years. If this were the case, it would happen every time there's an eruption in Hawaii. While my concerns may have no scientific proof what so ever, I really think it's a bad idea for us with present technology to drill a hole in the planet, We do this every day when we drill for oil... The holes aren't as deep. Drilling a hole in the crust could cause, at worst, a new volcano to erupt. It would be limited in scope by the amount of excess ( not when we don't have the ability to move. Try it on a diffrent planet for christ sake, while this means waiting for a more mature space program, I don't think this is a bad idea. And where would you have us move to? We're not going anywhere for hundreds of years, in any quantity anyway ( A few men to the Moon or Mars doesn't count)

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:Actually discussing proposition

[Colin Douglas Howell]

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 :-)

Yeah, I suppose the body of the paper is really aimed at other geophysicists. Sorry about that. I didn't try to thoroughly comprehend all his calculations either, since I've left the field and haven't studied any of this stuff in about a decade. But I think I got the gist of his ideas. Let me try to answer your points.

1) The reason you use all that iron isn't to keep the blob hot. (Actually, it stays hot by itself; as it falls, the gravitational energy released from its fall heats it up. But this extra heat is conducted away to the surrounding rock, so the blob won't get too hot and melt the probe.) To reach the core, the iron is pushing on the bottom edge of a vertical crack, forcing it open all the way down. But to force the crack open, you need a lot of weight. Hence the big mass of iron. A blob of radioactive material would have to be almost as big to do the job, and would be a lot more expensive and...hard to work with. :-)

Reading that part of the paper again, I notice that he's referring to an existing, accepted theory used for understanding the movement of molten magma upward through cracks in the crust. It works in the same way, only upward (because the molten magma is lighter than the surrounding rock, unlike the iron here, which is heavier). The point is that this part of the idea is based on an understood phenomenon.

2) I think that comment was meant to be tongue-in-cheek, just like the paper title.

3) Well, the crack closes up, but there's still going to be a narrow fracture where the crack was. The crack isn't going to instantly heal, since mantle rock at that depth and pressure is solid. And there might also be a small amount of iron left behind in the crack. As he said in his annotation, "This may be a problem with the whole idea."

4) I think the idea here is mostly to investigate the outer core, not the intervening mantle. (As I recall, the mantle is much better known than the core.) So he doesn't care about measurements until the probe reaches the core. Once the liquid blob reaches the liquid outer core, it will presumeably spread out and mix somehow, while the probe, being solid, will keep sinking for a bit, long enough to function for a while with appropriate engineering. :-) This is where things get fuzzy for me; since the probe was built to be neutrally buoyant in the blob, how does it cease to float around in blob material once it gets to the core? Would its material have to be chosen to change density at the proper pressure so that it would start to sink?

5) Actually, he's really saying that we don't know much about how the intervening material distorts a seismic signal. But the neat thing about digital signals is that as long as you can read the bits, you don't care too much about the shape of the waveform. That's not true when "imaging" earth's interior using the travel times of earthquake seismic waves. Also, the idea is to send the data using compressional waves, which travel through liquid just fine. Of course, you're right that you'd have to get lots of practice transmitting data seismically first.

Naturally, I realize this idea is heavily on the loony side. That's what made it fun to read and think about. :-)

Re:Actually discussing proposition

[Anonymous Coward]

yep your right - the main issue I have with this is the instrumentation - how do you sample the material surrounding the molten iron? By hoping that some of it dissolves /is soluble into the iron and sample that? That will tell us little we don't already know, and haven't already done in the lab ( to much higher precision no doubt!). And how do you transmit this information, and what sampling equipment can you put into a gratefruit ;) ? (alloys/materials do exist that are in equilbrium with pure iron at elevated temperatures - however, wether they are or not at megabar pressures I don't know!)

The heat source is not a problem - current theories of core formation presume iron rich diapers dropping the the center of an accreting planet under gravity - releasing gravitational potential energy as they go. Hence, use of a large amount of iron is effectively analogous to what is supposed to have happened as the core initally formed. On a personal note, I think these current models of Earth formation are hunting in the wrong (high pressure) direction and a simpler solution exists.

Core composition (and as such planetary formation) *is* a hot topic (no pun intended) however, it is currently easier to sample deep space than the not-so-deep earth. Hence anything to get people thinking about how little we know of the earth is NO BAD THING! (geologists have a horrible habit of taking model that is contrary to the facts as correct. c.f. plate tectonics. Kicking them up the bum with a new idea is a great thing in my book!)

Re:Actually discussing proposition

[Anonymous Coward]

Colin is right, the S-waves (secondary waves, one of three types of seismic waves produced by an earthquake) travel well through water and liquids. P-waves (primary) do not.

Another consideration, if we were to use radioactive "goo" (as previously suggested) that simply used gravity to fall towards the center then we assume that the interior of the earth is liquid. In actuality, the inner core is solid iron and nickel due to the enormous pressure. The goo would thunk against the inner core and make a noise similair to Lady Deathstrike's adamantium-ed head hitting the bottom of the containment pool in X-Men 2.

Re:Actually discussing proposition

[Anonymous Coward]

I assume that we are tunneling into the middle of the earth for a reason? The most complelling I've read so far is geothermal reasons so we can use the heat inside the earth to create an unlimited supply of power. But why not tunnel just deep enough, down to the layer where all carbon has been turned into millions of tons of dimonds by heat and presure. Then just buy more oil.

Re:Actually discussing proposition

[cylcyl]

This sounds like an interesting way to get rid of nuclear waste!

Re:Actually discussing proposition

[Odinson]

"(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?"

That's easy. Do this on a miniscule unpopulated tropical Island that you would need to buy anyway. If you cause a volcano than you have a big tropical island to build lots of resorts on. :)

mmmmm science. Hoola girls mmmm.

I like how articles like this...

[kmeson]

...describe in technical terms what any three year old knows instinctively, eg:

Imaging above benefits from the richness of the electromagnetic spectrum and the transparency of space at many wavelengths, including visible light.

and

Although travel downwards is aided by gravity, it is impeded by the dense intervening matter.

Oh, yeah. That'd work.

[porkchop_d_clown]

The iron probe slowly sinking into the molten core of the moon....

Except, how big a bomb would we need to re-melt the moon's core? It's been frozen for a few billion years now...

Re:Oh, yeah. That'd work.

[Jeeza]

It has probably been frozen from about the time it separated itself from the earth...

China Syndrome

[DakotaSandstone]

That reminds me of what Wilford Brimley ("eat oatmeal!") said in The China Syndrome.

The China Syndrome is where an unregulated nuclear reactor core is so hot, it melts through its container, and any rock underneath it. Theoretically all the way to China (or until groundwater gets in its way)

Great movie, BTW.

Newsflash!

[Anonymous Coward]

Probe surrounded by molten iron reveals earth's core much like molten iron.

Re:Data? What data?

[dynoman7]

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.

nuclear blast is tiny.

[Anonymous Coward]

The crust of the earth is about 40 miles thick, a nuclear blast would only just scratch the surface. How about dumping the molten iron down a mine-shaft instead. That's much deeper than any nuclear dirt digging could ever hope to achive. In short, using a nuclear weapon is a stupid idea.

Not to defend the theory, but

[acecccp]

"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. "

Why not just make another hole starting in China, so that the two meet in the center? I'm not in any way saying this whole idea isn't completely ridiculous, but I just don't see your point as being the bottleneck.

but?

[pimpinmonk]

But everyone knows that a giant dildo-shaped unobtanium nuclear-powered omnibus thingy would work much, much better!

product placement for AMD

[Camel Pilot]

I what electronics package are they going to use to operate above the temperature of iron?

So AC you are one of:

[ishmaelflood]

Amend, Jan P. Biogeochemistry T
Arvidson, Raymond E. Planetary Geology; Department Chairman T
Blank, Carrine E. Molecular Geomicrobiology T
Criss, Robert E. Stable Isotopes T
Crozaz, Ghislaine Cosmochemistry T
Dymek, Robert F. Metamorphic and Igneous Petrology T
Fegley, Bruce Planetary Geochemistry and Cosmochemistry T
Haskin, Larry A. Planetary Surface Materials T
Hofmeister, Anne M. Mineral Physics R
Jolliff, Bradley L. Geology, Petrology, and Geochemistry of the Earth, Moon, and Mars R
Korotev, Randy L. Lunar Geochemistry R
Levin, Harold L. Paleontology T
McKinnon, William B. Planetary Geophysics and Dynamics T
Morris, Julie D. Isotope Geochemistry, Magmatism and Tectonics R
Pasteris, Jill D. Biomineralization and Fluid-Rock Interactions T
Phillips, Roger J. Planetary Geophysics and Tectonics T
Podosek, Frank A. Isotope Geochemistry T
Smith, Jennifer R. Quaternary Geology, Geoarchaeology, and Paleoenvironmental Reconstruction T
Smith, Joshua B. Vertebrate Paleontology and Paleoenvironment Reconstruction, Sedimentology T
Smith, William H. Observational Astronomy, Planetary Physics T
Tucker, Robert D. U-Pb Geochronology, Regional Geology, Tectonics T
Wiens, Douglas A. Seismology and Geophysics T
Wysession, Michael E. Seismology and Geophysics T
Zinner, Ernst K. Astrophysics and Space Physics R

Or a liar

Re:So AC you are one of:

[Anonymous Coward]

I bet that it's Julie Morris. I bet she just loves to say "mahgmah"...

I Hope This Project Goes...

[istartedi]

...straight to Hell. :)

Old idea

[teakillsnoopy]

Sorry to ruin your prof love-in, but this idea has appeared before.
Look up "The day the Earth screamed" by Sir Arthur Conan Doyle. Good read.

Viral Marketing

[Anonymous Coward]

I can't help but think that someone in charge of Public Relations for The Core is stitting at home right now drinking a beer and laughing at how easy that was... Free marketing to the exact market that likes sci-fi.

I used to do PR work for a major automotive company and this is exactly the kind of thing we'd do to get chat rooms and bulletin boards buzzing about our product.

Hook, line and sinker.

humor? what?

[machine of god]

This gravity has been in the hands of the evil earth regime for too long! It's time that we liberated the gravity from the infidel's grasp! Crusaders, to mesopotamia!

Yep that's the movie.

[Nick Driver]

Seems like lots of /.'ers have seen it too, my memory was a bit foggy about it since it's been over 25 years since I've seen it last.

How much for a ticket??

[countach]

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.

Re:How much for a ticket??

[Arcturax]

You wouldn't make it. Even if you could survive the initial dousing in molten iron, and you wouldn't, the trip is one way. Once down there, explain to me how you plan to get back out?

Re:How much for a ticket??

[Jeeza]

What need would there be to go up to the molten iron anyway ? There are no diamonds or whatever to be found there.

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.

Old Sci-fi Movie

[aaaurgh]

Reminds me of an old film I saw as a kid - "The Day The Earth Split In Two", I think.

Scientists drilled a deep shaft then fired a rocket (a probe of some sort) down it. Unfortunately this caused an earthquake nearby and the crack started moving slowly round the planet until, despite all efforts, it came back to the start. The closing scene was the view from space as a large cone (about 30-40%) af the earth floated off and the core spewing out.

It was a typical 50/60's B movie, really corny and it scared the hell out of me, I couldn't sleep properly for weeks. Who needs The Matrix...? bring back the good ol' B movie. ;-)

Problem

[anwyn]

Iron is lighter than Uranium.

Re:Problem

[Anonymous Coward]

and what's your point?

Do you realise how long would it take?

[Anonymous Coward]

The Earth's mantle is made of hot, viscous rock. But this viscosity is only evident over geological time scales.

The viscosity is approximately equal to glass. That's right: glass! Glass is also liquid over long periods of time. Wait a couple of centuries, and the plate glass in your home will have sunk downwards, like warm toffee.

So it should only take a few million years for the probe to reach the outer core. I hope the researcher's tenure lasts that long.

Pat Boone is shirtless at the Earths core

[Anonymous Coward]

Beware! If my movie knowledge is correct Pat Boone, an Icelandic Guy, a Red Head MILF and Cpt. Nemo along with a German Bad guy are all at the center of the Earth fighting giant blue screen iguanas wearing paper fins. On a plus note, there ARE giant mushrooms!

Re:Pat Boone is shirtless at the Earths core

[Jeeza]

Actually you are mixing up two movies : Voyage to the Center of the Earth, and 20,000 Miles Beneath the Sea, both inspired by books from Jules Verne. Captain Nemo was the inventor of the Nautilus (a submarine) in the second one of these books.

Crack in the earth ... Stupid idea?

[ehiris]

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?

Re:Crack in the earth ... Stupid idea?

[barakn]

For starters, volcanos and tectonic spreading centers are areas where magma is moving upwards, which would tend to force your probe upward. Also, the chambers and tunnels that feed a volcano don't necessarily go straight up and down, and almost certainly don't extend all the way down to the core, so you'd run the risk of your probe landing on a rock shelf and not going anywhere. And many volcanos are plugged up, slowly building up explosive pressure. Mess with that and you might launch your probe into the stratosphere instead of downward. With a self-forming, self-healing crack created by a blob of iron, we don't have to worry about trying to use pre-existing channels that may or may not actually be there.

What!?

[ablokeuk]

We can use fantasticum and expensonium to make the probe to survive the conditions and hey rather than seismic wave comms use tachyon waves that way we get the results before blowing a hole in the earth and can decide if we should bother or not.

Oh and I have this project for changing the orbit of the moon if anyone would like to fund me?

Being serious for a moment this proposal is so impossible and so expensive currently it is pointless and if this guy spent more than a day on it he should have his funding removed. Hopefully it was an idle thought experiment that a few journalists got carried away with.

Re:What!?

[Jeeza]

You are certainly making sense, to me at any rate. As far as I know there is no "unobtainium" yet like in the movie "The Core" to make this probe be impervious to a heat of 5000 degrees and be able to withstand incredible pressures which don't even exist at the bottom of the seas and which cause molten iron to become solid again. And how would they keep the probe in the midst of that giant drop of molten iron ? And moreover, gravity would be enough to make it descend to the outer frontier of the core, but why would it, and how could it, go lower as it would not be heavier than the material the core is composed of ? I think that movie may have incensed a lot of ptople's imaginations, and this proposal may well be just a result of this.

LIGO? no way

[vinylat33]

LIGO is about gravitational waves and not seismic activity. LIGO tries to measeure ripples in space-time and it takes masses like 10 times the sun to even get the ripple spotted on the detector.

http://www.minigrail.nl is trying to do the same thing, only smarter and cheaper.

I know that this is not serious...

[EpsCylonB]

I know that this is not serious... but am I the only one that doesn't even want to contemplate opening up fissures and filling them nuclear weapons, other radioactive material or something else equally high energy.

I'm no scientist but is this really the easiest way to get data ?

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?

That gives whole new meaning..

[varjag]

..to the term 'core dump'.

The Core?

[CrazyTalk]

Ok, how many people immediately thought of the recent cheesy movie "The Core"? Don't they realize that doing this will cause massive superstorms and the destruction of the earth? I wonder if thats where this "Scientist" got his ideas from.

Silly

[Cackmobile]

I am in total agreence with lots of people. Who knows what this will do. Its the entire planet we are talking about. If we screw this up, well Game Over for humans. How much thought has gone into this. It seems like something I would ahve thought up when i was 12. Bad idea.

Re:Silly

[Jeeza]

I suggest you go watch the movie "The Core", and watch very carefully. It is not as stupid as it may sound. The dangers to the planet, however, may be very real.

Re:Silly

[Anonymous Coward]

No, the dangers to the planet aren't very real.

The amount of energy released in a large nuclear blast are small compared to other earth processes. At absolute worst, any damage would be very localized. What dangers do you forsee?

Exactly what material?

[Eudial]

... would sustain that ammount of heat? and exactly what data did they plan on finding down there?

Re:Exactly what material?

[druxton]

The latest chip from AMD sustains that amount of heat just fine thank you.

Initial reaction

[MiniMike]

From the headline I thought this was going to be another story about overclocking.

More seriously- there are plenty of materials which will withstand just above molten iron temperatures, but it gets a lot hotter than needed to melt iron further down. And let's not forget the pressure. Most of the high-temperature materials are ceramics, which are also less dense than molten lead. So unless you have a bunch of denser-than-lead inside the probe, all you have is an expensive float. Also, the shell material may survive high temperature, but it does not block it. Certainly after a day or two (probably much sooner) the heat would conduct through the shell and melt the stuff (instruments, controls, etc) inside. And I haven't even discussed the communications and power problems yet!

He was your teacher?

[Anonymous Coward]

Wow, would you please grant me a date? I would like you to do nasty things to me! I can't believe he was your teacher; you turn me on!

Who else thinks

[Sgt_Jake]

that poking a big hole in the earth is a bad idea?

I'm just thinking that if that crack creates a weak fissure, we're going to create a hell of a volcano when that blob hits the high pressure liquid zones... I guess what I'm really thinking is that it's time to quit working as a henchman for Dr. Evil, because I've seen the end of this movie, and the whole secret complex (3 miles southwest of Las Vegas) blows up.

Re:Data? What data?

[Tablizer]

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

Can you hear me now? Good!....Can you hear me now?....

A stupid simulation

[barakn]

Fill a tall glass (or similar container w/ clear sides) with vegetable oil. Pour a teaspoon of water colored with food-coloring (red for iron?) on top. You may repeat this many times, as it also simulates the formation of the Earth's core from myriads of iron blobs.

Even more offtopic...

[John Bayko]

Anyone interested in slightly skewed fiction, see if you can find a copy of "Flyboy Action Figure Comes With Gasmask", by Jim Munroe. One of the characters in the book actually could do that to the world, on a bad day, with just a thought...

Interesting story.

The real "real" problems.

[Christopher Thomas]

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?

"Squishing" only occurs when there is a difference in pressure between two parts of the craft. If the craft is all at one pressure, it feels nothing.

The real problems you have to worry about are volume and crystal structure changes with pressure. Air at 1000 atmospheres has a very different volume than air at 1 atmosphere. Iron at 1000 atmospheres, on the other hand, has a not-too-different volume. Build your craft out of materials that react similarly to pressure and make it tolerant of volume changes, and no "squishing" occurs.

Crystal structure changes are a tougher problem. Squeeze carbon, and it becomes diamond. Squeeze other materials, and they go through their own allotrope phases. Mechanical properties will change, and more importantly, electrical properties in semiconductors will also change.

There's also the small matter of keeping semiconductors working above the melting point of iron, but that may be an attainable goal (certainly not with silicon, but IIRC diamond's temperature limits were far, far higher, and other high-temperature semiconductors doubtless exist). Refrigeration is not an option - that big a heat gradient will be next to impossible to maintain with solid-state refrigeration systems, and you're not going to use refrigeration based on changing fluid pressures for materials strength reasons pointed out by another poster.

In summary, the real "real" problem is keeping the probe's electrical system working with the heating and material-structure changes that go on as the probe descends. Keeping the probe's physical structure intact is not a problem as long as you don't try to maintain voids of low pressure material.

Probes that can survive high temperatures and high pressures would have a number of interesting applications. Dropping one into Jupiter's deeper layers would be at least as much fun as dropping one into Earth's mantle, for instance.

Re:The real "real" problems.

[Guppy06]

""Squishing" only occurs when there is a difference in pressure between two parts of the craft."

No, it doesn't. Water at depth is denser than water at the surface, just as your body tissue is denser at 1 atm than in a vacuum. You seem to be confusing straight compression with other forms of deformation (a tennis ball concaving, for instance).

"Iron at 1000 atmospheres, on the other hand, has a not-too-different volume."

We're not talking about 1000 atm, though. 10 m of sea water is about 1 atm, so you hit 1000 atm at only 10 km below the surface of the ocean. The earth's radius is ~6000 km, and the vast majority of it is orders of magnitude denser than water.

"Crystal structure changes are a tougher problem. Squeeze carbon, and it becomes diamond."

Which demonstrates that "squishing" occurs even without a pressure differential.

Besides, I think the more immediate problem is "squeeze something, and it gets hotter."

"Dropping one into Jupiter's deeper layers would be at least as much fun as dropping one into Earth's mantle, for instance."

We have yet to be able to make a probe that can even survive the Venutian atmosphere for any length of time longer than a few hours. And this from the people who built supersonic fighters capable of taking off and landing in grass fields.

Re:The real "real" problems.

[Christopher Thomas]

""Squishing" only occurs when there is a difference in pressure between two parts of the craft."

No, it doesn't. Water at depth is denser than water at the surface, just as your body tissue is denser at 1 atm than in a vacuum.

I am aware of this, and stated as much in the next paragraph of my message.

Volume does not change drastically - certainly not enough to destroy a probe. It's pressure _gradients_ and shear stresses that you have to worry about, as they are what will tear apart, crush, or otherwise mutilate the craft. A pressure gradient occurs if you try to keep a low-pressure cavity intact in the craft, and shear stress comes if you have two materials with different Young's modulus in the craft's structure. Avoid both, and you're fine.

We're not talking about 1000 atm, though. 10 m of sea water is about 1 atm, so you hit 1000 atm at only 10 km below the surface of the ocean. The earth's radius is ~6000 km, and the vast majority of it is orders of magnitude denser than water.

The "1000 atm" number was chosen for the example because it's about the point at which air would liquify at room temperature. Talking about air at a million atm would be silly, as it would no longer be a gas.

Your density numbers also seem to be way off. Far from "orders of magnitude", density's only about double what it is at earth's surface (density of the lower mantle's about 6 g/cm^3, compared to a 1 atm density of around 3 for olivine, and density of the core's about 10-13 g/cm^3, compared to a 1 atm density of about 8 for iron). Given a corresponding volume change for a given amount of material, this represents a change in dimensions of about 25%.

Solid matter is *difficult* to compress. Packing atoms much more tightly than their natural spacing means smaller electron wavelengths, which means much higher electron energies. That energy has to come from somewhere, which means you're going to have to put in a lot of work to get it to that compressed a state. With relatively small deformation, that means a lot of pressure to perform that amount of work.

Besides, I think the more immediate problem is "squeeze something, and it gets hotter."

You're thinking of gases, which have a greater volume change (heat buildup is related to the amount of work done compressing the gas). You're also thinking of adiabatic systems - where there is little time for energy exchange with the environment. When compression occurs slowly, heating is minimal, because the heat that does build up quickly leaks away into the environment.

The earth has a temperature gradient because there's a strong heat source in the core, not because of pressure. What the heat source is is up for debate (most think radioactive decay, some still think latent heat of crystallization), but as the heat energy deposited flows out towards the surface, you get a temperature gradient.

We have yet to be able to make a probe that can even survive the Venutian atmosphere for any length of time longer than a few hours. And this from the people who built supersonic fighters capable of taking off and landing in grass fields.

Venus's atmosphere is highly corrosive. The mantle is less so (though still pretty reactive at those temperatures). The atmosphere of Jupiter is much less so. This presents a bigger barrier to long-term survival that pressure, and is my first guess at why the Venus landers stopped functioning.

Some sources, please?

[kiwimate]

The most powerful bomb of which I'm aware was a 50 or 58 MT bomb (depending on the source) on Novaya Zemlya.

"The world's most powerful hydrogen bomb was detonated on the 30th of October 1961 [over Novaya Zemlya]. The bomb had an explosive force of 58 megatons, or almost 6,000 times more powerful than the Hiroshima bomb. The bomb was dropped by an aircraft, and detonated 365 metres (1,200 feet) above the surface. The shock wave produced by this bomb was so powerful, it went thrice around the earth. The mushroom cloud extended almost 60 kilometres into the atmosphere."

Links:

George Washington University
The Bulletin
Bellona Foundation

And just how was the surrounding water ignited in the Fusion reaction? As I say...links please.

Why be inside the iron?

[56ksucks]

Why not just drop the empty blob of iron to the center of the earth, wait until it stops, and then send the probe down the hole it created? That way the probe doesn't have to be encased in molten iron.

will gwb be raiding both halves, then?

[wumpwump]

what with the two decentralized terrorist networks...?

Cool Disney Ride

[Scroatzilla]

Cool, then we could have a Disney ride where you go through the center of the Earth, then up an elevator into outer space!

Geez, slashdot rejected the story from me...

[ErikBaard]

Maybe next time I'll write my article with a British accent -- "mad scientist" and other such "boffin" stories go over better that way!

http://www.wired.com/news/technology/0,1282,5882 4, 00.html

stupid

[dnahelix]

stupid stupid stupid