Exploding star may have sparked Earth disaster

Duck and cover: Detonations of rogue stars

This is a supernova remnant known as E0102-72. The picture is a composite of images from the Hubble and Chandra space telescopes.

(CNN) -- Piecing together clues from astronomy, paleontology and geology, scientists have proposed that an ancient supernova may have damaged the protective ozone layer around the Earth and wreaked havoc on terrestrial life.

The researchers theorize that a group of young stars prone to short, cataclysmic lives passed relatively near our solar system several million years ago.

"Nobody had realized that this cluster of stars ... could have been so close to Earth during the (time)," says astronomer Narciso Benitiez.

Along with his partner Jesus Maiz-Appellanis, Benitez dug around in the geologic record for evidence that one of the rogue stars detonated with the Earth in the blast zone.

"When I did a search, one of the first things that popped out was a 1999 finding," Benitiez says. A team of German astronomers had found an unusual variety of iron in samples drilled from the Earth's crust below the ocean floor.

The Germans hypothesized that the iron isotope originated from a supernova, but knew of no suspect stars in our celestial neighborhood when the strange metal was thought to have dusted the planet, Benitez says.

But Maiz-Appellanis and Benitez did some detective work and came up with the likely culprit -- a volatile star pack known as the Scorpius-Centaurus OB Association, which passed relatively near the solar system several million years ago.

The Scorpius-Centaurus horde

A crucial break in the detective case came from a fortuitous source, Benitez's wife, microbiologist Matilde Canelles, whom Benitez enlisted to search the fossil record for clues.

Canelles found strong evidence that a catastrophe killed off a large population of marine organisms about two million years ago.

Her husband calculated that the Scorpius-Centaurus horde so was close to the Earth at the time, that if one of them had gone supernova, the powerful energy blast could have stripped away much of the ozone layer, which protects terrestrial life from harmful solar ultraviolet rays.

"This would have produced a significant reduction in phytoplankton abundance and biomass, with devastating effects on other marine populations, such as bivalves," Benitez says.

The scientists acknowledge that more study is necessary to confirm their theory. But if it proves correct, there's little to worry about from Scorpius-Centaurus.

The next member of the gang expected to go supernova is Antares, which at roughly 500 light-years away is too distant to rattle our planet, they say.