Quote:
Originally Posted by kennyc
but it doesn't answer the question as stated.
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Then I honestly don't understand what the question is-- because that
is the answer to "what heats the Earth's core."
""We don't think this original heat is a major part of the Earth's heat, though," Marone says. It only contributes 5 to 10 percent of the total, "about the same amount as gravitational heat.""
"For all this, however, Marone says, the vast majority of the heat in Earth's interior—up to 90 percent—is fueled by the decaying of radioactive isotopes like Potassium 40, Uranium 238, 235, and Thorium 232 contained within the mantle. These isotopes radiate heat as they shed excess energy and move toward stability. "The amount of heat caused by this radiation is almost the same as the total heat measured emanating from the Earth." "
From:
http://www.physorg.com/news62952904.html