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Researchers then scoured the globe for thin layers of radioactive isotopes in rock strata and in 1999 struck figurative gold: Samples from beneath the ocean revealed some hard metallic layers, known as ferromanganese crusts that form slowly over millions of years, containing iron-60, an isotope with a half-life of 2.6 million years -- so short that the material must be much younger than Earth. The iron-60 was in a stratum laid down 2.2 million years ago. Similar layers of iron-60 have since been found elsewhere in the oceans. Astronomers have also been scouring the skies for groups of stars that...

Millions of years ago, a series of nearby supernovae sent radiation and debris raining down to Earth. The events left traces of radioactive iron-60 embedded in the sea floor and even on the Moon, and now, researchers are saying they may have had life-altering effects on the early inhabitants of our planet. At just hundreds of light-years away, two major stellar explosions may have spurred changes to the environment, and even increased the rates of cancer and mutation.

An international team of scientists has found evidence of a series of massive supernova explosions near our solar system, which showered Earth with radioactive debris. The scientists found radioactive iron-60 in sediment and crust samples taken from the Pacific, Atlantic and Indian Oceans. The iron-60 was concentrated in a period between 3.2 and 1.7 million years ago, which is relatively recent in astronomical terms, said research leader Dr Anton Wallner from The Australian National University (ANU). "We were very surprised that there was debris clearly spread across 1.5 million years," said Dr Wallner, a nuclear physicist in the ANU Research...

Martin Bizzarro of the University of Copenhagen and his colleagues set out to determine the amount of iron in the early solar system. To do so, they measured nickel-60, a decay product of iron-60, in eight meteorites known to have formed at different times during the first 3 million years of the solar system. The meteorites that formed more than about a million years after the start of the solar system contain significantly more nickel-60 than do those that formed earlier, the team found. In a neighborhood of young stars, only a supernova could have produced iron-60, the parent of...

Might also answer poser: 'If supernovae were popcorn...' NASA's Hubble telescope has spotted the most distant massive star explosion of its kind ever, one which could help boffins understand the very fabric of the universe. Hubble view of supernova SN Wilson The telescope picked out Supernova UDS10Wil, also known as SN Wilson, in the night sky. The star apparently blew up over 10 billion years ago, and the resulting light from the explosion took that long to reach Earth. Wilson is in the special class of Type Ia supernovae, which give astroboffins a consistent level of brightness that can be...

We exist, therefore we question. Or at least, that paraphrases (poorly) an old quote from an old scholar... We know the masses and general composition of the four inner (rocky) planets in our solar system, and from basic chemistry, we know the number of atoms in a gram of any material. Multiplying Avogadro's number x the mass of these four planets, dividing by a weighted average atomic weight for the materials in each planet, we get about 3 x 10^ 50 heavy nuclei produced since creation/the big bang. Take your pick, that's the number of atomic nuclei we have to...

About 2.6 million years ago, an oddly bright light arrived in the prehistoric sky and lingered there for weeks or months. It was a supernova some 150 light years away from Earth. Within a few hundred years, long after the strange light in the sky had dwindled, a tsunami of cosmic energy from that same shattering star explosion could have reached our planet and pummeled the atmosphere, touching off climate change and triggering mass extinctions of large ocean animals, including a shark species that was the size of a school bus. The effects of such a supernova—and possibly more than...