A Stardust Grain from a Supernova Reveals the Birth of Rare Strontium
The Murchison meteorite, which fell in Australia in 1969, holds dust grains older than the Solar System. Among them are tiny graphite grains smaller than a thousandth of a millimeter. In five such grains, researchers found the isotope strontium-84: its atoms are slightly lighter than ordinary strontium.