When I was a kid, I liked to dig holes in my yard in Cincinnati. My grandpa joked that if I kept digging, I would wind up in China.
If I had actually been able to dig directly through the world, I would have come out in the Indian Ocean, about 1,100 miles (1,800 kilometers) west of Australia. That's the antipode, or opposite point in the world's surface area, from my town.
I just had a garden spade to move the earth. When I struck rock, less than 3 feet (1 meter) listed below the surface area, I could not go deeper.
Now, I'm a geophysicist and understand a lot more about Earth's structure. It has 3 primary layers:
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The external skin, called the crust, is an extremely thin layer of light rock. Its density compared to Earth's size resembles how thick an apple's skin is to its size. When I dug holes as a kid, I was scratching away at the really leading of Earth's crust.
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The mantle, which lies underneath the crust, is much thicker, like the flesh of the apple. It's made from strong, heavy rock that streams approximately a couple of inches annually. Hotter rock increases far from Earth's center, and cooler rock sinks towards it.
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The core, at Earth's center, is made from super-hot liquid and strong metal. Temperature levels here are 4,500 to 9,300 degrees Fahrenheit(2,500 to 5,200 degrees Celsius).
Earth's external layers put in pressure on the layers beneath, and these forces increase gradually with depth, simply as they carry out in the ocean– consider how pressure in your ears gets more powerful as you dive much deeper undersea.
That's pertinent for digging through the Earth due to the fact that when a hole is dug or drilled, the walls along the sides of the hole are under incredible pressure from the overlying rock and likewise unsteady since there's void beside them. More powerful rocks can support larger forces, however all rocks can stop working if the pressure is terrific enough.
(Credit: Volcan26/Wikimedia, CC BY-SA) The Earth is comprised of layers. The lithosphere is the strong, external part of the world, consisting of the breakable upper part of the mantle and the crust.
When digging a pit, one method to avoid the walls from collapsing inward under pressure is to make them less high, so they incline outside like the sides of a cone. An excellent guideline is to make the hole 3 times broader than its depth.
Unsteady Walls
The inmost open pit in the Earth is the Bingham Canyon Mine in Utah, which was dug with excavators and dynamites in the early 1900s to mine copper ore. The pit of the mine is 0.75 miles (1.2 kilometers) deep and 2.5 miles (4 kilometers) broad.
Considering that the mine is more than 3 times larger than it is deep and the walls are sloped,
