Hole Drilled to Bottom of Earth's Crust

AtariAmarok writes "A new article is up on LiveScience about a hole drilled into the Earth's crust to explore the layers of our planet's substrate. The hole gets closer to the mantle than any other efforts that have gone before. The hole might reach the "Moho" (division between Earth's brittle outer crust and the hotter, softer mantle) within a few years." From the article: "The depth of the Moho varies. This latest effort, which drilled 4,644 feet (1,416 meters) below the ocean seafloor, appears to have been 1,000 feet off to the side of where it needed to be to pierce the Moho, according to one reading of seismic data used to map the crust's varying thickness."

Wait a minute...

[darkitecture]

Wait a minute...

Are you trying to tell me that this whole damn time, we've never broken through the earth's crust and seen the mantle for ourselves? We can send something 8.7 billion miles away [wikipedia.org] but we can't drill two miles down? Doesn't this strike people as a bit odd or disconcerting?

Personally I'd like to learn just as much about the earth under my feet as the stars above my head.

I'd like to see this get more funding and see us reach the mantle in the next few weeks instead of waiting for some time in the "coming years."

Re:First they pearce the crust...

[smoketetsu999]

I doubt it, worst case scenario? They create a new volcano. Volcanos usually start underwater and build up in time when it flows and cools into new layers. There are small underwater volcanos all over the ocean.

Re:Help me out...

[Teun]

But how smart is drilling into the core of the earth? Aren't they asking for one huge volcano?

Such a bore hole is typically only a few centimeters (10-15) across for a depth of several kilometers, the rising lava would cool down and solidify within a few hundreds of meters.

And what about terrorism.

If you'd read TFA you would have known this drilling is a very high tech exercise.
Doing it at several places simultaneously would require the worlds best equipment, even the CIA might notice...

But then, during the cold war some of the worlds largest nuclear explosions were already set off at the bottom of bore holes (a.o. in Nevada) and so far without much damage to anything more than a few kilometers away.

By the way, the story is weird in calling a 1400+ meters hole the third deepest ever drilled.
The oil industry routinely drills more than 6000 meters below the sea floor.

Re:Help me out...

[Anonymous Coward]

The energy already being released by normal volcanoes and earthquakes is far more than we could produce with nuclear weapons.

Shouldn't you instead be comparing the energy released by normal volcanoes and the energy released by volcanoes initiated by a manmade charge (if indeed a charge in such a bore-hole could produce any such effect)?

If it were possible, for example, to crash the fault in the Bahamas with a nuclear charge, the resultant super-tsunami would also cause more damage to the US than the original explosion(s) relocated from the Bahamas to the US east-coast would, wouldn't it?

Re:At what cost?

[MillionthMonkey]

Your tax dollars at work. How much money did this cost?

Here we go again.

In order to avoid these inevitable comments that appear in every thread with a scientific topic, I suggest that no international research project be allowed to proceed unless it has been cleared by a panel of Anonymous Cowards who have been convinced after watching the teevee for too long that all science is really a scam to squander their tax dollars on foolishness like basic research that shows no promise of an immediate economic benefit such as a drug that makes your peepee harder.

In response to your question, you might be able to maintain a botched occupation for a few hours with the money.

Re:First they pearce the crust...

[Anonymous Coward]

First they pearce the crust, then they reach the mantle? Did I get that right?

Almost. First they PIERCE the crust.

Re:Drilling Technology Upgrades Needed

[Anonymous Coward]

They already do this, it is a source of energy - I forget what it is called, but they use the thermal energy in the earth to heat cylinders of water, from which the steam is used to turn turbines.

The only issue which has sparked random fears is if we're accelerating the rate at which we cool the earth's core - this is bad. I'm not entirely clear on it, and the original poster would probably know more, but I don't think we have enough data to be sure of anything on that issue.

Also, it's very expensive. And if something breaks, it's even more expensive to fix.

Re:scooped by Saturday Night Live

[Anonymous Coward]

If you want to be really scared just look a few comments up in the thread. A Friends quote (with Joey no less!) has got a +5 Funny.

Sad times for /. indeed. I think the balance has finally tipped. /. officially now has more AOLers than geeks.

Re:Would it work?

[Anonymous Coward]

no, the good thing is that dumb assess don't have control of our nukes.

oh wait.... they do

*shudders*

Re:Not a deep hole.

[GISGEOLOGYGEEK]

Yes, it is harder, but you are not 'digging' a hole, you are boring into the ground with a tube that supports the ground around it, usually lubricated with a slippery drilling mud that is pumped down the tube, out the drill bit.

The drill bit is designed either to cut a tube of drill core from the rock that is recovered intact to the surface for analysis, or else to grind up the rock and wash out the material with the pumped water.

Usually the start of the hole is 'cased' ... bored at a wider diameter, using the wider drill string in as a liner to support the hole while a smaller drill string continues through it deeper.

Re:is it wise?

[ColaMan]

Way to totally miss the point.

The poster was describing how the earth is not like a balloon and that you cannot compare them.

Then, without any apparent thought or reasoning, you try and compare a balloon and a tyre.

Note that he mentioned that there was a small amount of pressure in the balloon. This is because balloons are stretchy - they stretch quite easily when inflated.

Tyres are a lot less stretchy, being:
(a) A hell of a lot thicker than your average balloon.
(b) bound and reinforced internally with plies to keep the whole thing from blowing up like .... a balloon.

Tyres are a lot closer to a rigid disc than a balloon - they will (generally) only inflate to a certain volume. After that, the air pressure in a tyre rises substantially, allowing you to suspend your 1500kg car on a cushion of air trapped in the tyre.

Re:Drilling Technology Upgrades Needed

[jaakkeli]

If these guys can drill a hole this deep in a mere three weeks and nearly hit the Earth's mantle, doesn't it seem that it should be possible to directly harness the abundant heat energy in these holes?

So, you drill a hole, put some pipes to bring water there and up. Bringing the heat up will obviously cool the rock that touches your pipe, but as the rock cools, your power production drops. You can only produce energy sustainably if you limit the rate to such that the heat transfer from the rest of the crust is fast enough to balance the cooling. And even if it is really hot down there, the stuff isn't necessarily a good conductor of heat, so this can be a severe limitation to power production. Remember all the nature films where you've seen underwater lava flows: once the stuff starts pouring into water, the surface will solidify quickly, but the inside will be hot for a long time. It's because the water cools the surface fast and the heat doesn't transfer equally quickly to the surface of the rock.