David Todd, aged 10, of Peoria, Ill. for his question:
What is at the core of the earth?
Maybe you have heard that the core of the earth is a raging furnace. That is a startling idea, but nothing to worry about, If there is such a furnace, no one has ever seen it. For no one has tunneled more than two or three miles into the earth, And the middle of the earth is almost 4,000 miles under your feet,
What we know about the center of the earth is gathered from detective work, We can make some good guesses, But we do not know for sure what is there or how hot it is.
Most of our information about it is given to us by the rumbling earthquakes.. They start shocks and vibrations that travel on and on. Some of the vibrations travel around the earth and some travel through it, Different substances vibrate in different ways.. On their way down, earthquake shocks seem to ‑pass, through Iayers., of different substances. The layers seem to get heavier and denser the nearer they get to the middle of the earth.
About 4,000 miles down, at the very center of the earth‑, is the center of gravity, The center of gravity is always busy pulling everything towards it. The heaviest stuff tends to sink down lowest, So it is most likely that the heaviest stuff in the earth is in a ball far, far below our feet.
Imagine the load of outside stuff piled on what is in the middle.. A few miles down, every square inch of rock is buried under a, ton of rock above it. This pressure makes heat. In deep tunnels, the temperature rises one degree Fahrenheit every 65 feet. Imagine the heat and pressure 1,000 or 2,000 miles below our foot;
The pressure at 1802 miles down is 22,000 tons over every square inch., At this point, the seething core of the earth is thought to begin. The temperature and pressure is hot enough to melt any rock, metal or ore of which the earth is Made.
However., the hot core of the earth cannot be blazing away like a furnace. In order to do that it would need space and air. And remember it is boxed in under a hard crust some 1502 miles thick. The big ball of hot materials is caged in very, very securely. The heavy materials down there are thought to be mostly iron and nickel. Some experts believe that the core of the earth is pressed into a. sort of plastic state.
Maybe you guessed this hot stuff bursts out as volcanoes. Not at all, Volcanoes are formed a few miles below ground, The fiery heart of the earth is almost 2,000 miles below their roots, So there is no need to worry that the hot core of the earth may someday burst forth and burn us all.