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isotopes
Why isn't there far more radiogenic matter making up the planets? How is it
that massive stars create far less isotopes than stable mattter? |
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isotopes
Wonton Lee wrote:
Why isn't there far more radiogenic matter making up the planets? *How is it that massive stars create far less isotopes than stable mattter? Haven't you just answered your own question? The unstable isotopes (an isotope is just a particular species of an element--some are stable and some unstable) are made just as stable ones are, but by and large they don't last as long. So the matter that lasts is made largely of stable isotopes--some originally made in the stars, but others that are the stable products of radioactive isotopes. Those radioactive isotopes that do have long half-lives are well represented in planetary mass. -- Brian Tung posting from Google Groups The Astronomy Corner moved to http://www.astronomycorner.net/ Unofficial C5+ Home Page at http://www.astronomycorner.net/c5plus/ The PleiadAtlas Home Page at http://www.astronomycorner.net/pleiadatlas/ My Own Personal FAQ (SAA) at http://www.astronomycorner.net/reference/faq.html |
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isotopes
Wonton Lee wrote: Why isn't there far more radiogenic matter making up the planets? How is it that massive stars create far less isotopes than stable mattter? far less unstable matter (isotopes) than stable mattter. |
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isotopes
Wonton Lee wrote:
Why isn't there far more radiogenic matter making up the planets? How is it that massive stars create far less isotopes than stable mattter? At the time of a supernova explosion they do create lots of exotic neutron rich species that in part power the luminous decay. They don't stay around for long without decaying into more stable elements. See for example: http://www.pha.jhu.edu/~qzhang/seminar1bfigs/node3.html A fresh young planet would have a higher proportion of medium half life radioisotope species. U235 was once common enough on Earth that a natural water moderated nuclear reactor formed in the Gabon. http://www.ocrwm.doe.gov/factsheets/doeymp0010.shtml These days we only see natural species with half lives of the order of 10^9 years or decay products of things with that sort of lifetime. Isolating short lived Promethium from a stock solution of Uranium is a classic wet chemistry radioisotope lab experiment for students. Regards, Martin Brown |
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