A team of researchers from Germany, Austria and Australia has found traces of the radioactive isotope iron-60 — the tell-tale signature of a supernova explosion — within fresh snow in Antarctica. The Kohnen Station in Antarctica. Image credit: Sepp Kipfstuhl. Iron-60 (60Fe) is a radioactive isotope of iron. It is produced from pre-existing stable iron isotopes by a process called ‘neutron capture’ in the layers of massive stars where...