<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On Apr 9, 2011, at 2:03 AM, Kelly Anderson wrote:</div><br><blockquote type="cite"><div>Given that the core is heated by nuclear fission,</div></blockquote><div><br></div><div>Geothermal heat does not come from nuclear fission, 80% of it comes from the decay of radioactive isotopes, primarily Potassium Uranium and Thorium; the remaining 20% comes from the formation of the Earth when a large cloud of matter was compressed by gravity into a small ball 8000 miles in diameter, all that gravitational potential energy was converted into heat. </div><div><br></div><blockquote type="cite"><div>Well, you didn't mention nuclear fusion. </div></blockquote><div><br></div>Because fusion has not yet reached theoretical break-even and produced one watt of usable power (other than in the H bomb), and it is even further from economic break-even.<br><div><br></div><blockquote type="cite"><div>True we can't do it today,but perhaps someday with a lot of AI we might figure it out.</div></blockquote><div><br></div>Maybe, but we can't base our future on some marvelous new discovery made at some unspecified time that may or may not even happen.</div><div><br></div><div> John K Clark<br><div><br></div><div><br></div></div><br></body></html>