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Author Topic: Lunar Core  (Read 2271 times)

Offline Titanscape

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Lunar Core
« on: 20/10/2005 18:10:00 »
How hot is it in there, in the moon's core? Perhaps it is not completely cooled yet. Perhaps it will never cool right down. So do you think there may be some nuclear activity still going on deep inside? Or is the fuel all used up?

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another_someone

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Re: Lunar Core
« Reply #1 on: 21/10/2005 00:20:01 »
quote:
Originally posted by Titanscape

How hot is it in there, in the moon's core? Perhaps it is not completely cooled yet. Perhaps it will never cool right down. So do you think there may be some nuclear activity still going on deep inside? Or is the fuel all used up?

Titanscape



http://www.psrd.hawaii.edu/Sept99/MoonCore.html
quote:

The data were collected in April 1998 while the Moon swung through the north tail lobe of Earth's magnetosphere. The spacecraft magnetometer detected changes in Earth's magnetic field thus giving the researchers the information they needed to estimate the size of the Moon's core. That size came out to be very small. Hood and his collaborators report a lunar core radius of only 340 km 90 km. For an iron-rich composition, a core of this size represents merely 1 to 3% of the Moon's total mass. In contrast, Earth's core is about 33% of our planet's total mass. This new evidence for a small lunar core strengthens the popular giant impact hypothesis which says that the Moon formed from hot, rocky debris after a Mars-sized object smashed into the early Earth. Down to its very core, the Moon has a unique history in our Solar System.



This does not directly answer your question, but it does suggest that there is not very much of a core to heat.

As for nuclear activity, as far as I can ascertain, even in the model of the Earth's core, the theory of a nuclear fusion core seems at present to be a minority theory, although it still has some proponents.
 

Offline gsmollin

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Re: Lunar Core
« Reply #2 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."
 

The Naked Scientists Forum

Re: Lunar Core
« Reply #2 on: 21/10/2005 14:00:05 »

 

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