WASHINGTON (AP) -- Astronomers have witnessed a cosmic explosion bigger and brighter than any except the Big Bang.
Orbiting telescopes got the fireworks show last spring when they spotted what is known as a gamma ray burst in a far-off galaxy.
NASA astrophysics chief Paul Hertz calls it "a once-in-a-century cosmic event." A gamma ray burst happens when a massive star dies, collapses into a brand-new black hole, explodes in what's called a supernova and ejects energetic radiation.
Astronomers say a planet caught in one of these bursts would lose its atmosphere instantly and would be left a burnt cinder.
But because the blast was 3.7 billion light-years away, mankind was spared. In fact, no one on Earth could even see it with the naked eye.
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