Here is a new scientist story about using the KamLAND detector to identify antineutrinos from the radioactive decay of semi-stable isotopes (such as U-238) inside the Earth.

http://www.newscientist.com/article.ns?id=...=mg18725103.700

The article points out that this is a first result, and that a lot of refinement is possible with future detectors, so that a more solid number for total power can be determined, and a map of the distribution can be made.

The article didn't indicate what the energy of these antineutrinos are, or how we know they aren't coming from another source, though I bet if we look up recent papers by Bill McDonough, we could find out those details.

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Here is a story about neutrino detection that also addresses geothermal energy production.

From the story: This is the first story I've seen that dealt with the causes of heat production in a somewhat quantitative way. Note that if we had to convert from fossil fuel energy production to geothermal, we would have to be very efficient.

When neutrinos are detected, are we seeing energy (photons) of absorption of the neutrinos or are we seeing a catalytic effect of the medium reacting to the neutrino passing through it?

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Hi GOURDHEAD,

This is the same story as my anti-neutrino story from yesterday, and I agree with you that it is very cool that they are able to make a quantitative analysis of the radioactive heat being generated by the Earth's core.

I'm merging these two threads.

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I wonder what produces the remaining 11 to 23 billion kilowatts of heat. Convection maybe? Tidal flexing?

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I would guess tidal flexing. Some of it may be non-equilibrium cooling. Convection can only transfer energy.

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Repeated from the story:
On rereading this I noticed that a power value was given not an energy value. It seems likely that they measured the heat content of the Earth not the rate at which heat is being generated. As we monitor this over a few decades we may learn whether heat is being produced faster (or slower) than convection and conduction are dissipating it. It should get pretty scary if heat is being generated faster than it is dissipated. We may learn of one of the processes that cause planets to explode. The rate of heat transfer by convection in the Earth's interior must be hard to estimate, let alone measure, but we should have some good data on conduction. Convection rates may vary over difficult to estimate ranges.

__________________
For those inclined to oppose human meddling with the structure of the universe or the composition and configuration of objects and groups of objects within the universe, consider:
Whether there is a limit to the magnitude of a modulation of chaos below which order remains invariant? Or, is order but a fiction invented by perspectives applied over finite, however large, time intervals?

Nature.com has an article by Philip Ball with the cheesy title, "Ghostly particles unearth core radioactivity": http://www.nature.com/news/2005/050725/ful...l/050725-7.html.

At Japan's KamLAND antineutrino detector there was a study indicating that some of the neutrino activity they've observed was a product of radioactive decay deep inside the earth. The article has several names for your search for other studies on the matter of exploring the balance in what produced and is producing heat inside our planet.

As Ball observes, "Most of what is known comes from studying seismic tremors passing through the planet. These can reveal boundaries between different kinds of rock. But antineutrinos produced by radioactivity in the mantle can tell researchers something about the chemistry down below."

The article, and the report on which it was based, has no final answers but gives hints at the search that is ongoing.

Sorry I missed the existing discussion. I thought I looked the titles over pretty well. Thanks for moving my note to here.

This thought continues to nag at me. If "the estimated 30 billion to 44 billion kilowatts" is a measure of power (joules per second) being generated in the Earth's core and/or the "softer" parts of the mantle as opposed to a measure of the flow of heat away from there, how can we "estimate" the thermal stability of the Earth's core.

__________________
For those inclined to oppose human meddling with the structure of the universe or the composition and configuration of objects and groups of objects within the universe, consider:
Whether there is a limit to the magnitude of a modulation of chaos below which order remains invariant? Or, is order but a fiction invented by perspectives applied over finite, however large, time intervals?

Gourdhead, even if it were overheating, we have abundant evidence of what the earth does when pressure builds--from individual hotspot vulcanism like Hawaii and Yellowstone to plate techtonics from the Atlantic Ridge spread to the Pacific Ring. It bubbles up, pops through, and spreads out. As fractured as our crust is, there will be oodles of opportunity for pressure releases.