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Not to freak you out, but there’s a gamma ray-blasting stellar mass pointed in your direction

Friends of the Dark Side, your time may soon be at hand. It seems we have a literal death star aiming in our general direction. The culprit is part of a binary star system—two stars which orbit each other—by the name of WR 104.

Both are massive and very, very hot. One will eventually explode into a harmless supernova, providing us with a lovely astronomical light show. The other, however, might be deadly.

The evil stellar mass in question is a Wolf Rayet star. When these stars die and the right conditions are met (they must be 30 times more massive than the sun and fast-rotating), they run the risk of collapsing into a spinning black hole, around the axis of which would be powerful jets of high-energy gamma radiation. Turns out, the star meets the criteria. And guess what? Earth is right in its line of fire.

Peter Tuthill at the University of Sydney in Australia and his colleagues watched WR 104 for 6 years, during which time they saw 10 full orbits and captured them on camera using the Keck telescopes on Mauna Kea, Hawaii. The research is published in the Astrophysical Journal.

It is unclear how direct the burst would have to be to have an effect, says Tuthill. It has been variously postulated that a burst angle of 2–20º might put us outside the danger zone, but Tuthill says that even a miss of 12º would be dangerous for life on Earth.

A mass-extinction event on Earth some 450 million years ago might have been triggered by a gamma-ray burst. Adrian Melott at the University of Kansas in Lawrence, who suggested this in 2003, says that the new observations of WR 104 are big news because this is the first candidate system spotted that could produce a similar Earth-walloping gamma-ray burst in the future. “If it were a full gamma-ray burst and we were caught in the beam, the effects would be pretty severe,” says Melott. “My guess is that there would be a lot of death from it, rather like a small-scale nuclear war.”

A gamma-ray beam might not kill us all immediately. First there would be a bright flash, possibly blinding people, says Melott, then after a few hours the effects would begin in earnest.

The gamma rays would break up molecules in the atmosphere, producing particular oxides of nitrogen that would start to eat up the ozone layer after a few hours, says Melott. Within a few days a quarter of the ozone layer would be destroyed, he suggests.

The ozone destruction would allow through enough ultraviolet light to cause severe radiation damage to plants and people. The nitrogen oxides would also cause acid rain that could kill off plants and algae. - Read the full story, Death Star Found Pointing At Earth