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17 April 2014 12:48 pm ,
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Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Midnight Burst Thrills Astronomers
9 May 2005 (All day)
Astronomers may have for the first time witnessed the colossal crash of two neutron stars on the fringes of a distant galaxy. A NASA satellite detected a sharp flare of energy just moments after 12 midnight EDT on 9 May, triggering hours of intense research by telescopes on the ground. Analysis is ongoing, but a neutron-star merger--if confirmed--would help explain a type of explosion that has puzzled researchers for years.
The blasts, called gamma ray bursts (GRBs), come in two varieties. A "long" burst, lasting from seconds to a few minutes, arises from a gigantic star that explodes when its dense core collapses and creates a black hole, according to the leading theory. But "short" bursts, emitting pulses of gamma rays in fractions of a second, are utterly mysterious. Astrophysicists hypothesize that some short GRBs should come from colliding neutron stars, the dense spinning remnants of supernovas that do not form black holes.
Now, a NASA satellite called Swift has caught the first short GRB witnessed directly by astronomers. The satellite picked up a spike of gamma rays lasting 1/20th of a second from the constellation Coma Berenices. In less than a minute, the satellite swiveled to point its x-ray telescope at the GRB. It detected 11 x-ray photons--an extremely faint signal, but enough to notify ground-based telescopes of the approximate location. As the night progressed, at least two telescopes--the 3.5-meter WIYN Telescope at Kitt Peak, Arizona, and the 10-meter Keck I Telescope at Mauna Kea, Hawaii--saw a faint patch of light within that search area, near a galaxy about 2.7 billion light-years away. The galaxy is a blob of ancient stars where no new stars have formed for billions of years.
The outskirts of such an old galaxy is exactly where astronomers expect to see neutron stars collide, says Swift lead scientist Neil Gehrels of NASA's Goddard Space Flight Center in Greenbelt, Maryland. The scenario is this: Supernova explosions expel a pair of neutron stars out of their native galaxy and into deep space. Then, it takes billions of years for the pair to spiral together in a brief fury of energy, probably coalescing into a new black hole. "Everything seems to fit," Gehrels says. "It's the most interesting possibility for short bursts."
The excitement is warranted, says theorist Shri Kulkarni of the California Institute of Technology in Pasadena, California. Still, he warns, researchers have studied their images for just a few hours. They must confirm that the patch of light seen by their telescopes came from the burst itself and not from an unrelated object at a different distance.