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Physics, Astronomy & Cosmology / Re: Lunar Core
« on: 21/10/2005 14:00:05 »
I am not a geologist, so this is not gospel, but I remember that heat of radioactive decay is supposed to provide much or all of the core's energy. The outer core is molten iron, and the inner core is solid, but detailed composition is uncertain. Iron, definitely, but should contain significant uranium and related actinides. Heavy elements would naturally sink as the earth formed so radioactivity is inevitiable. The amount of it, and how much heat it releases are the scientific issues.
Since the moon is thought to have formed from the earth by an impact, after its core was formed, the moon's composition would be crustal and mantle, but little core. Since the moon is also smaller, it would have a core that probably supports some radioactive decay but not enough to keep it hot. There was obvious volcanism on the moon in the past, but much of that would have been the heat from gravitational binding energy escaping.
So the short answer to your question would be that the moon's core should be warm, not hot. There should also be some radioactive decay, courtesy of the small amount of heavy elements it inherited from the earth, but not enough to melt anything.
"F = ma, E = mc^2, and you can't push a string."
Since the moon is thought to have formed from the earth by an impact, after its core was formed, the moon's composition would be crustal and mantle, but little core. Since the moon is also smaller, it would have a core that probably supports some radioactive decay but not enough to keep it hot. There was obvious volcanism on the moon in the past, but much of that would have been the heat from gravitational binding energy escaping.
So the short answer to your question would be that the moon's core should be warm, not hot. There should also be some radioactive decay, courtesy of the small amount of heavy elements it inherited from the earth, but not enough to melt anything.
"F = ma, E = mc^2, and you can't push a string."