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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. :-)"
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.
If I have nothing to hide, don't search me
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.
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!
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.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"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?
"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.
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.
"I'm so moist I'm sticking to the leather." -Kermit the Frog on The Late Late Show