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</o:shapelayout></xml><![endif]--></head><body bgcolor=white lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'>>…</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowtext'> <b>On Behalf Of </b>Anders Sandberg<br><br></span><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";color:#1F497D'><o:p></o:p></span></b></p></div></div><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><span style='color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='color:#1F497D'>></span><span style='color:#1F497D'>>></span><span style='color:#1F497D'>…</span> Even I agree that a planet with plutonium oceans is unlikely to be habitable for life. -- Dr Anders Sandberg<o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'> </span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>>>…</span><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I learned a new thing by thinking about this. There is an isotope of plutonium which is non-fissile, 244. Get a sphere of the stuff, heat it to 900 and some Kelvin, you have an ocean of plutonium, with radioactive particles up the kazoo but no fission. Until Anders’ offhanded comment about an ocean of plutonium, I never knew there was such a critter. Ain’t science kewallll? {8-]</span><o:p></o:p></p></div></div><p class=MsoNormal><br><span style='color:#1F497D'>>…</span>Sounds like a great practical joke to do when re-engineering a solar system. A hot ecology based on plutonium as a solvent for some weird metal-oxide biochemistry/mechanochemistry. <span style='color:#1F497D'> </span>-- Dr Anders Sandberg<span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As practical jokes go, that one would be elaborate.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>As Anders’ comments often do, this notion of a plutonium sea has me pondering. Assume into existence a sphere of molten plutonium 244. The melting point of plutonium is not so high, about the same as magnesium and lower than that of aluminum, both of which are easy to melt for the home hobbyist, and even if not, most of us here have tossed aluminum soda cans into the campfire, so it isn’t glowing red when it melts.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>So I was starting to work on a heat model that has some interesting properties. If you assume the liquid plutonium planet out in space far from anything, at about 650K, ten over the melting point, it is easy to calculate the heat loss from radiation to space with Boltzmann’s law. Now take the radioactive decay energies, 80 million year half life for Pu244, then see what happens. There is an alpha decay to Neptunium 240 plus a helium atom at first, and helium reacts with nothing so that stuff comes bubbling to the surface, and the 240Np beta decays with a half life of about an hour to Pu240, which is fissible. The model’s future may depend on the initial radius of your planet, but it looks to me like the thing eventually explodes.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks Anders!<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>spike <o:p></o:p></span></p><pre><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></pre><pre><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></pre></div></body></html>