The main things that scientists want to know about a radioactive substance are its half-life and the kinds and energies of radiation it produces. As much work as researchers put into these determinations, the answers are not always clear. In February 2015, scientists at Australian National University (ANU) announced that they had determined the half-life of iron-60 to be 2.6 million years, and it was later decided that this measurement settled a long-running dispute involving differing measurements. Based on this half-life, a team that included three ANU researchers has shown that the Fe-60 detected in seabed crusts, delivered as part of the infall on Earth of material ejected from supernovae, arrived from two such stellar explosions within the past 10 million years.
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