A Nearby Supernova May Have Caused a Mass Extinction 2.6 Million Years Ago
Supernovae are the explosive end stages of massive stars. About 2.6 million years ago, one such supernova lit up Earth’s sky from about 150 light-years away. A few hundred years later, after the new star had long since faded from the sky, cosmic rays from the event finally reached Earth, slamming into our planet. Now, a group of researchers led by Adrian Melott at the University of Kansas believes this cosmic onslaught is linked to a mass extinction of ocean animals roaming Earth’s waters at the time — including the Megalodon. Earth’s inner core is probably softer than previously thought.
Seismologists from the Australian National University (ANU) have adapted a method used successfully to study the Earth’s crust and upper mantle to provide new evidence of what lies inside.
The idea of there being an inner core – a ball inside a molten outer layer – was proposed more than 80 years ago, when a Danish seismologist analysed anomalous results from seismograms following earthquakes in New Zealand.