I realize there are immense obstacles that stand in our way, as far as engineering and logistics go, but really I’m only talking about sending a probe, or some sort of complex instrument down to the core. Not some sort of fanciful manned mission.
I know there’s heat, pressure, great distance and even the unknown to overcome, but are there any theories built on sound principals that address such a task? And how insurmountable would some of these obstacles be? I can buy that it’s so impractical as to be prohibitive, but it must be possible, at least in theory.
Also, would the opening of an active volcano be a good place for entry? Would this get around having to burrow and drill through miles upon miles of crust?
The temperature at the center of the earth is nearly twice the melting point of the highest melting point element (Carbon), so barring the development of force fields or some really impressive cooling system, there is no way to do this.
Not going to happen with today’s (or even tomorrow’s) technology. Hell, we haven’t even drilled down very far through the outer crust yet…let alone to the inner mantle. From memory we’ve only drilled down 10’s of miles.
If you could do it in theory, you’d still need to dig through about 4,000 miles of very dense rock*. A machine that could do that would require immense power and maintenance, so now you need a crew and a lot of spare parts. It would need to be a pretty big machine.
*ok, the outer core is liquid iron but it’s 5 times denser than any rock from the crust that we’d be familiar with. Does the machine need to be dense enough to sink? Interesting thought. Since the machine is feeling less gravity pulling it downward and some gravity pulling it upward from the mass of the earth above it, how heavy would it need to be to sink through the outer core?
So, there would be no natural opening through the crust out into the mantle you might be able to send such a device? Let’s forget about the core for now, what about just getting into the mantle?
No, there can’t be. The pressure increases as you get deeper, so any crevice would be quickly shut. The conditions below us are nothing like the comparatively air-like top layer of the crust. Even volcanoes form because the magma is being pushed upward toward the region of lower pressure.
To have an opening, you have to posit a material that is stronger than the pressure, so strong that it can keep from collapsing into an open space. We know of no such natural materials, and we certainly don’t have any artificial ones that can cope with that much pressure over a large area.
Right. We know of and can manufacture materials which could be used for a space elevator. Admittedly, using the current manufacturing techniques, the total cost would be prohibitive (probably more than the entire world’s economic output for years), but the materials, though expensive, do at least exist. And of course there’s research being done on how to make nanofiber more cheaply, and it may in our lifetimes end up being cheap enough to be practical. For a core-diver, though, we wouldn’t even know where to start.
Remember, that iron is feeling the same gravity that the probe is feeling. Just like in any other situation, the one and only requirement for something to sink is that it be more dense than the fluid it’s in. Making the probe dense enough would be easy: Just ballast it with a bunch of lead or gold or osmium or whatever. If you were able to make the darned thing in the first place, of course.
Cooling wouldn’t do any good, for cooling an object you have to radiate away heat from it, for that the radiator system has to be hotter than the surrounding medium. Since the original problem was that there’s no material that would take the heat, you won’t be making a radiator that will hold up.
Well, assuming a closed system cooling contraption at least…
Before talk on that article goes any further, note that it’s envisioned only to reach the edge of the outer core, no more than 1600 miles or 40% of the way down. Molten iron isn’t going to penetrate a solid outer core of pressurized iron.
The instrument package is also still imaginary with current technology.