Natural Origin
Primordial nuclides found in the earth are residues from ancient supernova explosions which occurred before the formation of the solar system. They are the long-lived fraction of radionuclides surviving in the primordial solar nebula through planet accretion until the present. The naturally occurring short-lived radiogenic radionuclides found in rocks are the daughters of these radiactive primordial nuclides. Another minor source of naturally occurring radioactive nuclides are cosmogenic nuclides, formed by cosmic ray bombardment of material in the Earth's atmosphere or crust. For a summary table showing the number of stable nuclides and of radioactive nuclides in each category, see radionuclide. Radionuclides can also be produced artificially e.g. using particle accelerators or nuclear reactors.
Read more about this topic: Radioactive Decay
Famous quotes containing the words natural and/or origin:
“The great man knew not that he was great. It took a century or two for that fact to appear. What he did, he did because he must; it was the most natural thing in the world, and grew out of the circumstances of the moment. But now, every thing he did, even to the lifting of his finger or the eating of bread, looks large, all-related, and is called an institution.”
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