Could an molten Earth tunneler really be built?

Recently a geophysicist named David Stevenson was in the news with a semi-serious proposal about sending a probe to the center of the earth by creating a large crack in the crust and then filling it with molten iron, which would be heavier than the surrounding material and would propogate all the way down to the core, with a small probe in the center of the molten iron relaying information back to the surface using seismic vibrations. Here are some stories on this idea:

Dear Scott Jensen:

Beyond a mile or so, not possible.

Power source. No place to "pump" heat.

Beyond a couple of miles, no physical material can withstand the stress. The internal pressure of the rock is beyond the yield strength of the rock. Result: plastic flow. Besides, you said "already cooled" and "molten tunnelling". Which is it?

Its liquid-ish, just let it flow around.

What is cooling? Where do you send the heat to acheive cooling?

magnetic-repulsion

No possibility, unless you cool the core of the Earth. Like as not, the Earth would lose the majority of its magnetic field if you did this. We'd lose the Northern and Southern lights...

The other responder has the only serious attempt I am aware of.

David A. Smith

I'm not talking about going down but across. Along the lines of replacing the grind tunnelers that made the tunnel between UK and France.

Both. The leading point of the tunneler makes the rock molten but only until it can be pushed away to make the tunnel. Once in the proper shape, it is let to cool down.

The surrounding rock cools it back down.

Scott Jensen

On a very small scale, yes, there's a "microwave drill" out there which has been demoed, which does exactly that: drop a bunch of microwaves into a focused spot until it melts, insert high temp high strength "drill" bit which pushes the material aside, repeat as necessary.

I think... if I recall right, the work was done in Israel, using an off the shelf microwave oven system.

If I recall right from the energy input calculations they provided, this needed between 25 and 50 times the energy that a classical rock drill or boring machine does to tunnel through a given distance of rock. Ergo, it does not seem to be an economical volume boring method, though it may well be useful for specialized drilling applications into very hard materials and such.

Classical rock drills and boring machines are pretty well balanced, all things considered, for their jobs. There may be more energy efficient ways of drilling, or faster ways, but they're a pretty good well balanced design point.

-george william herbert snipped-for-privacy@retro.com

Dear Scott T. Jensen:

"Can be done" yes. It is more energy intensive, just as melting is more energy intensive. At least with grinding you can handle the loose stuff right away. And it takes less power.

David A. Smith

I have seen proposals to electrically heat a tungsten probe to high enough temps that the rock melts and the probe drops through the rock. The big problem, of course, is that it only goes down.

High powered lasers have been investigated for hole boring, as well. They are relatively fast, but inefficient.

Luke

Push it where?

Bob Kolker

Er... and without that interaction, we'd likely be the ones to be glowing, no?

In an unserious vein I remember a SF juvenile-class story called something like "Visitor From The Deeps" which had a vehicle based on the concept.

This is merely a fictional treatment from an amateur, but you've described to a "T" the way I started out one of my sci-fi stories:

The Bridge to Space

As to how practical the idea is, I haven't a clue. There was talk about a nuclear powered tunneller a while back, and I even swear I saw photographs of it while in Junior High, glowing orange-hot. But maybe I only saw a photo of a model illustrating the concept.

And don't forget "Tom Swift and his Atomic Earthblaster.".

Except that he didn't ride, just used the device to mine the molten iron.

Just to be retentive... :)

Stranger From The Depths Gerry Turner Doubleday 1967 Scholastic Books "edited and abridged" version 1970

From the land of UFO make-believe comes a little data, a _lot_ of suppositions, and partial answers to the material displacement problem... answers that bring us back to the "millions of tons of molten iron spearheading a crack ever-deeper into the Earth"... but operating on a somewhat smaller scale ;)

An antimatter particle beam?

The Bill of Rights - Void where prohibited by Law.

Dear Chuck Stewart:

No. The Van Allen radiation belts actually draw more charged particles to Earth. They do nothing at all for gamma or net-uncharged bodies.

Or Star Trek's "Horta" that dissolved the rock... but didn't displace huge amounts of vapor, even.

David A. Smith

"Chuck Stewart" wrote in news: snipped-for-privacy@gmx.co.uk:

His question was not about the iron blob to the core. He was asking about a simple melter to form a hole.

The DOE did some studies around 1970 using a heated tungsten tip as a possible alternative way to drill (deep) oil wells. Because of the exponential cost increase as you pass 15,000 feet a way was needed to bypass the constant cycling of the drill stem to replace worn bits.

Obviously the (electrically) heated tip was able to proceed without pulling the whole string, but costs were far beyond acceptable. It was cheaper to use a (ultra) high pressure water jet that could cut granite at about 1 cm per second.

ObSF: Oath of Fealty-Niven/Pournell Tunnel melter was used as jailbreak tool.

It's been done several times, and there some very detailed procedures for how to do it again, if you really want to.

The most successful example I can think of was that asteroid that created the Gulf of Mexico. It's supposed to have hit the Earth with sufficient energy to vaporize millions of tons of rock, and to make not only a nice deep hole; but also a rather impressive change in the climate of an entire planet.

The procedures for doing this on a smaller scale are actually pretty simple. Just find a nice big nuclear reactor, turn off the coolant, and then remove all the control rods. Careful calculations, and even some near-successful experiments, have demonstrated that this will produce enough concentrated energy to allow the reactor core to melt anything and everything around it, and to tunnel deep into the Earth as the ground on which it sits turns to liquid and vapor.

Now, if you want to do any of this on purpose, or with some modicum of control and safety, then that'll be a bit more difficult.

KG

Easily.

This is the fabled "Cina Syndrome", as in "melt a hole in the Earth all the way to China..."

Aside from the Amerocentric viewpoint it's quite possible for a reactor-gone-wild to burn a pit in the ground... a deep one if the situation is just right,

As I remember the scenario:

The reactor proper melts/vaporizes and the fissile material flows downward together into a mass. A very hot mass. Which begins to vaporize itself and the ground underneath it.

Down it goes, spewing a cloud of vaporized fissile material and earth/stone upwards. And the pit tends to keep the mass concentrated together despite its tendency to fly apart.

How long this goes on depends on the ammount and kinds of the fissile material in the mass.

I dunno how deep it might actually go...

Er... ten thousand times worse than Chernoble? More? Chernoble was "only" a meltdown...

If this newsgroup let things slide by, it would lose my respect. ;-)

I was thinking there would already be such cracks, but it if could them, fine.

Now does this patent really exist?

Scott Jensen

Could you site the sources for these small-scale experiments? Also, would the uncontrolled reactor get so hot that it would melt itself? And what about residue radiation once it has done its deed?

Scott Jensen