A rare radioactive plutonium isotope dating back millions of years has been recently discovered at the bottom of the ocean, leading experts to question how it originated on Earth.
The dangerous element known as plutonium-244 - discovered nearly 5,000ft below the Pacific Ocean in the ocean crust - is the result of violent cosmic events that occurred in deep space millions of years ago.
Plutonium-244 s presence on Earth suggests that an exceptionally violent event billions of years ago, such as neutron stars colliding, may have caused it to appear on our planet. The story is complicated - possibly this plutonium-244 was produced in supernova explosions or it could be left over from a much older, but even more spectacular event such as a neutron star detonation, the study s lead author, The Australian National University Anton Wallner said in a statement.