Did a supernova explosion once wipe out species on Earth’s surface?

It’s a terrifying thought: an exploding star near Earth, blasting our planet with cosmic rays which killed off species on the surface.

But it might have happened in our planet’s distant past, according to astrophysicist Brian Thomas from Washburn University in Kansas – although not in the ‘doomsday’ fashion many imagine.

Two supernova explosions which erupted 2.5 million and 8 million years ago may have blasted our planet, changing its atmosphere.

The two explosions were thought to have been far enough away that Earth would be outside the radiation ‘kill zone’ – but Thomas believes they could have had subtler effects.

Thomas said, ‘We are interested in how exploding stars affect life on Earth, and it turns out a few million years ago there were changes in the things that were living at the time. It might have been connected to this supernova.’

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Thomas says that the radiation from the stars might have depleted the ozone over hundreds of year – increasing the level of UV light that hit out planet.

Over a long period, it could have killed off or damaged various species – something that seems to match the fossil record 2.5 million years ago.

Thomas said, ‘There were changes, especially in Africa, which went from being more forested to more grassland. There is a subtler shift. Instead of a ‘wipe-out everything’, some are better off and some are worse off.’