Odd cosmic blast puzzles astronomers

Is it a gamma-ray burst? A supernova? Amateurs might weigh in


Before and after views show the area where the mysterious burst was detected. The image at left is from the Sloan Digital Sky Survey. The image at right is from NASA Swift's Ultraviolet/Optical Telescope. The burst — during which one star became brighter than the rest of its host galaxy — is the bluish spot at the center of the ellipse in the "after" image.

WASHINGTON - A new kind of cosmic explosion has been spotted in EarthÂ’s celestial neighborhood, and amateur astronomers in the Northern Hemisphere might be able to see it next week, scientists reported Thursday.

The blast seemed a lot like a gamma-ray burst, the most distant and powerful type of explosion known to astronomers.

But when scientists first detected it with NASAÂ’s Swift satellite on Feb. 18, the explosion was about 25 times closer and lasted 100 times longer than a typical gamma-ray burst.

“This is totally new, totally unexpected,” said Neil Gehrels, Swift’s principal investigator. “This is the type of unscripted event in our nearby universe that we hoped Swift could catch.”

The explosion originated in a star-forming galaxy about 440 million light-years away toward the constellation Aries the Ram. A light-year is about 6 trillion miles (10 trillion kilometers), the distance light travels in a year.

This would be the second-closest gamma-ray burst ever detected, if indeed it is one.

The burst lasted for nearly 2,000 seconds, or about 33 minutes, astronomers said in a statement. Most bursts last a few milliseconds to tens of seconds. It also was surprisingly dim.

Scientists at Italy’s National Institute for Astrophysics found hints of a budding supernova — an exploding star — when they saw the afterglow from the original explosion grow brighter in optical light.

If it is a supernova, scientists will have an unprecedented view of one from start to finish.

Scientists will attempt observations with the Hubble Space Telescope and Chandra X-ray Observatory. Amateur astronomers with dark skies above might be able to see the explosion with a 16-inch telescope.

More information and images are available online from NASA's Swift Web site.