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• Primordial_nuclide abstract "In geochemistry and geonuclear physics, primordial nuclides, also known as primordial isotopes, are nuclides found on the Earth that have existed in their current form since before Earth was formed. Primordial nuclides are residues from the Big Bang, from cosmogenic sources, and from ancient supernova explosions which occurred before the formation of the solar system. They are the stable nuclides plus the long-lived fraction of radionuclides surviving in the primordial solar nebula through planet accretion until the present. Only 288 such nuclides are known. All of the known 254 stable nuclides occur as primordial nuclides, plus another 34 nuclides that have half-lives long enough to have survived from the formation of the Earth. These 34 primordial radionuclides represent isotopes of 28 separate elements.Cadmium, tellurium, neodymium and uranium each have two primordial radioisotopes (113Cd, 116Cd; 128Te, 130Te; 144Nd, 150Nd; and 235U, 238U), and samarium has three (146Sm, 147Sm, 148Sm).Due to the age of the Earth of 4.58×109 years (4.6 billion years), this means that the half-life of the given nuclides must be greater than about 5×107 years (50 million years) for practical considerations. For example, for a nuclide with half-life 6×107 years (60 million years), this means 77 half-lives have elapsed, meaning that for each mole (6.02×1023 atoms) of that nuclide being present at the formation of Earth, only 4 atoms remain today.The shortest-lived primordial nuclides (i.e. nuclides with shortest half-lives) are: ..., 232Th, 238U, 40K, 235U, 146Sm and 244Pu.These are the 6 nuclides with half-lives comparable to, or less than, the estimated age of the universe. (In the case for 232Th, it has a half life of more than 14 billion years, slightly longer than the age of the universe.) For a complete list of the 34 known primordial radionuclides, including the next 28 with half-lives much longer than the age of the universe, see the complete list in the section below.The next longest-living nuclide after the end of the list given in the table is niobium-92 with a half-life of 3.47×107 years. (See list of nuclides for the list of all nuclides with half-lives longer than 60 minutes.) To be detected primordially, 92Nb would have to survive at least 132 half-lives since the Earth's formation, meaning its original concentration will have decreased by a factor of 1040. As of 2013, it has not been detected. It has been found that the next longer-lived nuclide, 244Pu, with a half-life of 8.08×107 years is primordial, although just barely, as its concentration in a few ores is nearly 10−18 weight parts. Taking into account that all these nuclides must exist since at least 4.6×109 years, meaning survive 57 half-lives, their original number is now reduced by a factor of 257 which equals more than 1017.Although it is estimated that about 34 primordial nuclides are radioactive (list below), it becomes very difficult to determine the exact total number of radioactive primordials, because the total number of stable nuclides is uncertain. There exist many extremely long-lived nuclides whose half-lives are still unknown. For example, it is known theoretically that all isotopes of tungsten, including those indicated by even the most modern empirical methods to be stable, must be radioactive and can decay by alpha emission, but as of 2013 this could only be measured experimentally for 180W. Nevertheless, the number of nuclides with half-lives so long that they cannot be measured with present instruments—and are considered from this viewpoint to be stable nuclides—is limited. Even when a "stable" nuclide is found to be radioactive, the fact merely moves it from the stable to the unstable list of primordial nuclides, and the total number of primordial nuclides remains unchanged.Because primordial chemical elements often consist of more than one primordial isotope, there are only 84 distinct primordial chemical elements. Of these, 80 have at least one observationally stable isotope and four additional primordial elements have only radioactive isotopes.".
• Primordial_nuclide thumbnail Elemental_abundances.svg?width=300.
• Primordial_nuclide wikiPageID "23105042".
• Primordial_nuclide wikiPageRevisionID "598881519".
• Primordial_nuclide hasPhotoCollection Primordial_nuclide.
• Primordial_nuclide subject Category:Geochemistry.
• Primordial_nuclide subject Category:Isotopes.
• Primordial_nuclide subject Category:Metrology.
• Primordial_nuclide subject Category:Radiometric_dating.
• Primordial_nuclide type Abstraction100002137.
• Primordial_nuclide type Atom114619225.
• Primordial_nuclide type Isotope114619658.
• Primordial_nuclide type Isotopes.
• Primordial_nuclide type Matter100020827.
• Primordial_nuclide type Part113809207.
• Primordial_nuclide type PhysicalEntity100001930.
• Primordial_nuclide type Relation100031921.
• Primordial_nuclide type Substance100019613.
• Primordial_nuclide comment "In geochemistry and geonuclear physics, primordial nuclides, also known as primordial isotopes, are nuclides found on the Earth that have existed in their current form since before Earth was formed. Primordial nuclides are residues from the Big Bang, from cosmogenic sources, and from ancient supernova explosions which occurred before the formation of the solar system.".
• Primordial_nuclide label "Elementi primordiali".
• Primordial_nuclide label "Nucléide primordial".
• Primordial_nuclide label "Nuclídeo primordial".
• Primordial_nuclide label "Primordial nuclide".
• Primordial_nuclide label "Primordiales Nuklid".
• Primordial_nuclide sameAs Primordiales_Nuklid.
• Primordial_nuclide sameAs Nucléide_primordial.
• Primordial_nuclide sameAs Elementi_primordiali.
• Primordial_nuclide sameAs Nuclídeo_primordial.
• Primordial_nuclide sameAs m.064nf7d.
• Primordial_nuclide sameAs Q759767.
• Primordial_nuclide sameAs Q759767.
• Primordial_nuclide sameAs Primordial_nuclide.
• Primordial_nuclide wasDerivedFrom Primordial_nuclide?oldid=598881519.
• Primordial_nuclide depiction Elemental_abundances.svg.
• Primordial_nuclide isPrimaryTopicOf Primordial_nuclide.