-----Original Message----- From: [email protected] > Note that a large part of the core of the Earth is hot, not cold, and also subject to a small magnetic field, yet nevertheless absorbs few of the neutrinos passing through it.
On the contrary, Robin - the hot core of Earth could be considered evidence of neutrino heating (or accelerated decay rates due to neutron flux). We do not know the actual contribution of every source. We do know the amount of neutrino flux at Earth' surface is astronomical, so to speak - around 7x10^10 neutrinos/cm^2/s ! Most of these would be non-solar in origin, but that does not change the intensity which is actually higher inside than on the surface. So-called "geo-neutrinos" which are generated in situ from beta decay, could account for a portion of the internal heat - which could be in addition to solar neutrinos. At least the geo-neutrino is evidence of alpha/beta decay QUOTE: Research has shown that Earth's total heat output is about 44 terawatts...we found roughly half of that comes from radioactive decay of uranium, thorium and other materials ... meaning that about 50 percent of the earth's heat comes from geo-neutrinos." END That statement from the reference below is confusing, and indicates that even the experts do not have much more than an informed guess. At one time, not too long ago - this internal heat was said to come from uranium fission - now fission is said to be all but non-existent (compared to decay). And furthermore - we know that beta decay itself is influenced by background neutrino flux. http://www.astrobio.net/topic/solar-system/earth/geology/half-of-earths-heat -from-radioactive-decay/#sthash.PQXjYiwj.dpuf In short, there is a good possibility that neutrino heating of Earth, especially via slightly accelerated decay rates of existing isotopes, has been underestimated in importance - especially considering increased neutrino absorption rates at higher density and higher heat of the deep core.
