Distant explosion breaks brightness records
"This is a once-in-a-lifetime event," said Rob Fender of Southampton University in the UK. "We have observed an object only 20 kilometers across [12 miles], on the other side of our galaxy, releasing more energy in a tenth of a second than the sun emits in 100,000 years."
Several dozen satellites around Earth, and one orbiting Mars, detected a flash of high-energy photons - known as gamma rays - on 27 December 2004. The 0.25-second flash was so bright it overwhelmed the detectors on many satellites - making an energy measurement impossible - and disrupted some radio communication on Earth.
"It was so bright, it came right through the body of the Swift satellite, even though Swift wasn't pointed at the object," says John Nousek, mission director for NASA's Swift spacecraft - launched especially to detect gamma-ray bursts (GRBs) - at Pennsylvania State University, US.
The brief flash was followed by a fainter afterglow of gamma rays lasting for about 500 seconds, which showed a recurring signal every 7.5 seconds. That signal led scientists using Europe's INTEGRAL spacecraft to trace the source of the "superflare" to a dead star - called a neutron star - known to spin at that rate. Measurements of the distance to the star - called SGR 1806-20, range from 30,000 to 50,000 light years from Earth.
That relatively small distance, coupled with an accurate energy measurement by NASA's RHESSI satellite, means the explosion was not as powerful - at source - as more distant bursts linked with black holes. Nevertheless, it "may have sterilised any planets within a few light years of it", says Rob Fender, an astronomer at Southampton University, UK, who is studying the lingering radio emission from the flare. "This may be a once-in-a-lifetime event both for astronomers and for the neutron star itself."
NewScientist.com news service
Several dozen satellites around Earth, and one orbiting Mars, detected a flash of high-energy photons - known as gamma rays - on 27 December 2004. The 0.25-second flash was so bright it overwhelmed the detectors on many satellites - making an energy measurement impossible - and disrupted some radio communication on Earth.
"It was so bright, it came right through the body of the Swift satellite, even though Swift wasn't pointed at the object," says John Nousek, mission director for NASA's Swift spacecraft - launched especially to detect gamma-ray bursts (GRBs) - at Pennsylvania State University, US.
The brief flash was followed by a fainter afterglow of gamma rays lasting for about 500 seconds, which showed a recurring signal every 7.5 seconds. That signal led scientists using Europe's INTEGRAL spacecraft to trace the source of the "superflare" to a dead star - called a neutron star - known to spin at that rate. Measurements of the distance to the star - called SGR 1806-20, range from 30,000 to 50,000 light years from Earth.
That relatively small distance, coupled with an accurate energy measurement by NASA's RHESSI satellite, means the explosion was not as powerful - at source - as more distant bursts linked with black holes. Nevertheless, it "may have sterilised any planets within a few light years of it", says Rob Fender, an astronomer at Southampton University, UK, who is studying the lingering radio emission from the flare. "This may be a once-in-a-lifetime event both for astronomers and for the neutron star itself."
NewScientist.com news service