WASHINGTON (AP) — Astronomers call it the monster. It was
the biggest and brightest cosmic explosion ever witnessed. Had it been
closer, Earth would have been toast.
Orbiting telescopes got the fireworks show of a lifetime last spring when
they spotted what is known as a gamma ray burst in a far-off galaxy.
The only bigger display astronomers know of was the Big Bang that created
the universe — and no one, of course, was around to witness that.
"This burst was a once-in-a-century cosmic event," NASA astrophysics chief
Paul Hertz said at a news conference Thursday.
But because this 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.
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. The radiation is as bright as can be as it travels
across the universe at the speed of light.
A planet caught in one of these bursts would lose its atmosphere instantly
and would be left a burnt cinder, astronomers say.
Scientists might be able to detect warning signs of an impending gamma ray
burst. But if one were headed for Earth, there wouldn't be anything
anybody could do about it.
NASA telescopes in orbit have been seeing bursts for more than two
decades, spotting one every couple of days. But this one, witnessed on
April 27, set records, according to four studies published Thursday in the
It flooded NASA instruments with five times the energy of its nearest
competitor, a 1999 blast, said University of Alabama at Huntsville
astrophysicist Rob Preece, author of one of the studies.
It started with a star that had 20 to 30 times the mass of our sun but was
only a couple of times wider, so it was incredibly dense. It exploded in a
certain violent way.
In general, gamma ray bursts are "the most titanic explosions in the
universe," and this one was so big that some of the telescope instruments
hit their peak, Preece said. It was far stronger and lasted longer than
"I call it the monster," Preece said. In fact, one of the other studies,
not written by Preece, used the word "monster" in its title, unusual
language for a scientific report.
One of the main reasons this was so bright was that relative to the
thousands of other gamma ray bursts astronomers have seen, the monster was
pretty close by cosmic standards. A light-year is almost 6 trillion miles.
Most of the bursts NASA telescopes have seen have been twice as distant as
this one. Other explosions could be this big, but they are so much farther
away, they don't seem so bright when they reach Earth, the studies'
Astronomers say it is incredibly unlikely that a gamma ray burst —
especially a big one like this — could go off in our galaxy, near us.
Harvard's Avi Loeb, who wasn't part of the studies, put the odds at at
least 1 in 10 million.
Our galaxy doesn't have many of the type of star that lends itself to
gamma ray bursts, said Charles Dermer, a co-author of the studies and an
astrophysicist at the U.S. Naval Research Laboratory.
"The chance of anything happening and being dangerous is virtually nil,"
Also, because a burst is concentrated like a focused searchlight or a
death beam, it has to be pointing at you to be seen and to be dangerous.
"Either it's pointed at us or it's not," Preece said. "If it's not, yay!
Civilization survives and we see maybe a supernova. If it were pointed at
us, then it matters very much how far away it is in our galaxy. If it's in
our local arm, well, we had a good run."
Some theorize that a mass extinction on Earth 450 million years ago was
caused by a gamma ray burst in a nearby part of our galaxy, but Dermer
said that's unlikely.
We don't see gamma ray bursts from the surface of Earth because the
atmosphere obscures them and because most of their light is the type we
cannot see with our eyes. That's why NASA has satellites that look for
This burst was so bright telescopes on Earth saw a brief flash in the
For scientists, this was a wow moment.
"These are really neat explosions," said Peter Michelson, a Stanford
physicist who is the chief scientist for one of the instruments on a NASA
gamma ray burst-spotting telescope. "If you like fireworks, you can't beat
these. Other than the Big Bang itself, these are the biggest there are."
The burst "is part of the cycle of birth and life and death in the
universe," Michelson said. "You and I are made of the stuff that came from