Science editor

WASHINGTON - Scientists say they have detected the brightest stellar explosion ever recorded, a new breed of supernova that may well be repeated sooner than they previously thought.

The violent explosion was observed by ground-based telescopes as well as NASA's orbiting Chandra X-Ray Observatory in a galaxy far from our own Milky Way. But the observations hint that an erupting star in our own galaxy, called Eta Carinae, could be close to the same kind of blast, astronomers say in a paper to be published in The Astrophysical Journal.

For years, scientists have been looking for a blast this big, but never found one until last September. After months of analysis, the research team discussed their findings at a news conference Monday here at NASA Headquarters.

"We discovered a supernova that stands out as far and away the most powerful, the brightest supernova that has ever been observed," the head of the research team, Nathan Smith of the University of California at Berkeley, told reporters.

The brightness of the supernova, which has been designated SN 2006gy, wasn't that obvious to earthly observers because the star that blew up was 240 million light-years from Earth, in a galaxy called NGC 1260.

But when astronomers took that vast distance into account, they figured that the supernova was 100 times more energetic than usual. Such a phenomenon would require the violent destruction of a star 150 times more massive than our sun — which is near the theoretical limit for a single star's size.

photo & story courtesy msnbc.msn.com, 05/07/07