text: A partial list of radionuclides not found on Earth, but for which decay products are present:
  Plutonium-244 and samarium-146 have half-lives long enough to still be present on Earth, but they have not been confirmed experimentally to be present.
  Notable isotopes with shorter lives still being produced on Earth include:
  *Manganese-53 and beryllium-10 are produced by cosmic ray spallation on dust in the upper atmosphere.
  *Uranium-236 is produced in uranium ores by neutrons from other radioisotopes.
  *Iodine-129 is produced from tellurium-130 by cosmic-ray muons and from cosmic ray spallation of stable xenon isotopes in the atmosphere.
  Radioisotopes 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).