“In Jules Verne’s classic novel Journey to the Center of the Earth, explorers find a hidden tunnel that takes them to a forgotten land filled with wild beasts and other wonders,” writes Dr. Kenneth Hicks, Professor of Physics and Astronomy, on Sunday, June 2, in the Columbus Dispatch. Hicks writes that new results from neutrino detectors help explain the primary heat source in Earth’s core−radioactive decay of trace amounts of uranium and thorium.
Of course, today we know that (Jules Verne) story is complete fiction, but scientists still wonder what is at the center of the Earth.
To measure Earth’s heat output, we now can use neutrinos, which are ghostly particles emitted when atoms undergo radioactive decay. These particles pass through matter freely with almost no interaction.Most of what we know about Earth’s interior is from measuring the speed of shock waves from earthquakes. From this, we get the familiar picture that the Earth has a thin crust on top of a thick region of liquid magma and a solid iron core at the center.With today’s technology, we can now probe Earth’s interior using neutrinos.First, some background. We all know that when a volcano erupts, lava flows out. But why is Earth’s mantle so hot? Conventional wisdom is that trace amounts of radioactive elements, such as uranium and thorium, produce that heat.
Some geologists speculate that there might be enough concentration of heavy radioactive elements at Earth’s core to make a dilute nuclear reactor, or geo-reactor, that would generate more concentrated heat at the core.
How Earth’s heat is generated is important to geologists who study continental drift. If more heat was generated in Earth’s core in the past, then this could affect things such as the rate of volcanic eruptions.
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