US astronomers detect most distant cosmic explosion
13/9/2005 15:49
Satellite and ground-based telescopes have detected the most distant
cosmic explosion so far observed, which occurred 13 billion light years away, US
astronomers reported Monday.
The gamma ray burst happened about 500 million
to 1 billion years after the Big Bang explosion from which point the universe is
believed to begin. The universe is currently estimated to be 13.7 billion years
old.
The explosion was detected on Sept. 4 by NASA's Swift satellite that was
launched in November 2004 and later by ground-based
telescopes.
Astrophysicist Don Lamb of the University of Chicago predicted
more detections ahead of similar explosions and gamma ray emissions even further
away in time.
Scientists hope the study of the distant explosions could help
them know more about the origin of the universe and the formation of
stars.
"We are finally starting to see the remnants of some of the oldest
objects in the universe, " Daniel Reichart of the University of North Carolina
told a telephone news conference.
Gamma ray bursts signal the death of
enormous stars and the birth of black holes. The afterglow of an explosion can
be seen for a few days at x-ray and optical wavelengths. The more distant the
explosion is, the later the afterglow reaches earth.
A light year is about 10
trillion km, the distance light travels in a year.
Xinhua News
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