World Library  
Flag as Inappropriate
Email this Article

Extinct radionuclide

Article Id: WHEBN0015711726
Reproduction Date:

Title: Extinct radionuclide  
Author: World Heritage Encyclopedia
Language: English
Subject: Thorium, Iodine, Index of physics articles (E)
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Extinct radionuclide

An extinct radionuclide is one that scientists believe was formed by primordial processes, such as stellar nucleogenesis in the supernova(s) that contributed radioisotopes to the early solar system, about 4.6 billion years ago. Generally, radioisotopes with a decay half-life shorter than about 100 million years are not found in nature, except for those generated continuously by a natural process, such as cosmic rays, or a decay chain of much longer lived isotopes, such as uranium or thorium. Other short-lived isotopes are thus seen only as extinct radionuclides, whose former existence is inferred now from a superabundance of their stable decay products.

Examples of extinct radionuclides include iodine-129 (the first to be noted in 1960, and inferred from excess xenon-129 concentrations in meteorites, in the xenon-iodine dating system), aluminium-26 (also inferred from extra magnesium-26 found in meteorites), and iron-60.

List of extinct radionuclides

A partial list of radionuclides not found in nature, but for which decay products exist:

Isotope Halflife (Myr)
Niobium-92 34.7
Curium-247 15.65
Lead-205 15.3
Hafnium-182 8.9
Palladium-107 6.5
Caesium-135 2.33
Technetium-98 4.23
Technetium-97 2.6
Gadolinium-150 1.798
Iron-60 2.62
Zirconium-93 1.53
Dysprosium-154 3.01

Notable isotopes with shorter lives still being produced on Earth include:

Radioactives with half-lives shorter than one million years are also produced: for example, carbon-14 by cosmic ray production in the atmosphere (half-life 5730 years).

See also

External links

  • List of isotopes found and not found in nature, with half-lives
  • Discussion of extinct radionuclides
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 



Copyright © World Library Foundation. All rights reserved. eBooks from World eBook Library are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.