Star explodes halfway across universe
WASHINGTON (AP) - March 21, 2008 The aging star, in a previously unknown galaxy, exploded in a
gamma ray burst 7.5 billion light years away, its light finally
reaching Earth early Wednesday.
The gamma rays were detected by NASA's Swift satellite at 2:12
a.m. "We'd never seen one before so bright and at such a
distance," NASA's Neil Gehrels said. It was bright enough to be
seen with the naked eye.
However, NASA has no reports that any skywatchers spotted the
burst, which lasted less than an hour. Telescopic measurements show
that the burst - which occurred when the universe was about half
its current age - was bright enough to be seen without a telescope.
"Someone would have had to run out and look at it with a naked
eye, but didn't," said Gehrels, chief of NASA's astroparticles
physics lab at Goddard Space Flight Center in Greenbelt, Md.
The starburst would have appeared as bright as some of the stars
in the handle of the Little Dipper constellation, said Penn State
University astronomer David Burrows. How it looked wasn't
remarkable, but the distance traveled was.
The 7.5 billion light years away far eclipses the previous naked
eye record of 2.5 million light years. One light year is 5.9
trillion miles.
"This is roughly halfway to the edge of the universe," Burrows
said.
Before it exploded, the star was about 40 times bigger than our
sun. The explosion vaporized any planet nearby, Gehrels said.
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On the Net:
http://www.nasa.gov/mission-pages/swift/main/index.html