Surprisingly the isotopes Iron-60 and Plutonium-244 were found in ocean sediments that are known to be between 3 and 4 million years old, and no, the Plutonium couldn't have come from nuclear bomb testing in the 1950s because nuclear bombs use Plutonium-239 not 244. Pu-244 has a half-life of 81 million years and Iron-60 is 2.6 million, so these elements must've been produced long after the Earth formed. A supernova can produce Iron-60 but it is thought that only a kilonova, the collision of two neutron stars, can produce plutonium-244. By taking into consideration the known age of the ocean sediment and the ratio of those two isotopes, a recent paper has calculated that those results could be explained by a kilonova exploding about 550 light years from Earth 3.5 million years ago.
Did a kilonova set off in our Galactic backyard 3.5 Myr ago? <https://arxiv.org/pdf/2311.17159.pdf> John K Clark -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/CAJPayv1wjXD9iDMUCnK6M3rG8fnppaau3pxBaBvGXcKbXYBnWg%40mail.gmail.com.
