主题：【科普】地热发电 -- 马鹿
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复 【科普】地热发电
一般认为，地热是由于地球物质中所含的放射性元素衰变产生的热量.
放射性元素衰变能维持几十亿年？
至少用放射性元素测算地球岩石年龄，很多地方都在30亿年。
又如钍232的半衰期是13亿年，而铷82的半衰期则将近50亿年。
复 怎么不可能
或衰变一克铷能产生多少热量？
以目前地热惊人的热量，反算出来放射性元素的含量会不会和目前地球元素含量比矛盾？
我不是学地质的。没法给你算。
这里有个链接。自己看。
http://www.physorg.com/news62952904.html
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."
Radioactivity is present not only in the mantle, but in the rocks of Earth's crust. For example, Marone explains, a 1-kilogram block of granite on the surface emanates a tiny but measurable amount of heat (about as much as a .000000001 watt light bulb) through radioactive decay.
That may not seem like much. But considering the vastness of the mantle, it adds up, Marone says.
我记得前段时间，国内的大理石板建材就有放射性超标的问题。算是一个注脚。