Learn what to look for in the night sky with today's Nerdy Curio from Stardate. It sounds more like bad science fiction than real science: Radiation from an exploding star kills off the biggest shark ever to inhabit the oceans. But a recent study says that could be what happened.

Researchers noted several bits of evidence to support the idea. For one thing, a series of supernova explosions beginning about eight million years ago cleared away gas and dust in our region of the galaxy, forming what’s known as the Local Bubble.

A supernova 2.6 million years ago, about 165 light-years away, created a torrent of cosmic rays — heavy particles formed in the explosion’s aftermath.

In the empty Local Bubble, the cosmic rays traveled to Earth almost unimpeded. And many of those that missed us were reflected back into the bubble by the magnetic field at its edge. The cosmic rays pelted Earth for decades.

At Earth, they rammed into particles in the upper atmosphere. That created showers of other particles, which then hit the surface. The researchers said that large creatures living in shallow coastal waters should have absorbed large doses of these particles, which could have killed them off.

The victims could have included megalodon — a relative of modern sharks that might have reached a length of 60 feet. It became extinct about the time of the possible supernova, as did many other species of life. So if this idea is correct, in the battle of Supernova versus Megalodon, victory went to the exploding star.

Script by Damond Benningfield

Aired February 15, 2019

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