All the bursts astronomers have recorded so far have come from
distant galaxies and have been harmless to Earth, but if one occurred
within our galaxy and were aimed straight at us, the effects could be
Currently orbiting satellites detect an average of about
one gamma-ray burst per day.
Measuring the exact rate is difficult, but for a galaxy of approximately the same size as the Milky Way,
the expected rate (for long GRBs) is about one burst every 100,000 to
Gamma-ray bursts are thought to emerge mainly from the poles of a
Only a small percentage of these would be beamed
Estimates of rates of short GRBs are even more uncertain
because of the unknown degree of collimation, but are probably
This creates two, oppositely shining beams of radiation
shaped like narrow cones.
Planets not lying in these cones would be
comparatively safe; the chief worry is for those that do.
GRB's can cause the following:
Deadly radiation levels
Chemical damage to the stratosphere
Nothing to do but hope you never get hit by one.
Swift GRB highlights
NASA's Swift satellite has given astronomers more than they could have
hoped for. Its discoveries range from a nearby nascent supernova to a
blast so far away that it happened when our universe was only 5 percent
of its present age.
April 13, 2010: NASA's Swift discovers its 500th burst. GRB 100413B is a long burst in the constellation Cassiopeia.
April 23, 2009: GRB 090423 in Leo holds the record for the farthest
burst yet known -- 13.04 billion light-years away. "The burst is beyond
the farthest confirmed galaxies and quasars, making it the most distant
object we know in the universe today," Fox said. This find validates
models suggesting that galaxy and star formation were well under way in
the universe's first billion years and that some early stars died as
March 19, 2008: GRB 080319B, in Boötes, is truly extraordinary. It
produces enough light to be seen briefly with the unaided eye, cresting
at visual magnitude 5.3 despite occurring 7.5 billion light-years away
-- or more than halfway across the visible universe. Scientists conclude
that one of its particle jets appears to have been aimed squarely at
July 14, 2007: GRB 070714B explodes in Taurus. Afterglow observations
indicate a distance of 7.3 billion light-years, making this one of the
farthest short bursts to date.
Feb. 18, 2006: GRB 060218 explodes in Aries 450 million light-years away
-- in our back yard, cosmically speaking. Although faint, the burst
emits detectable gamma rays for more than 40 minutes and detectable
optical and X-ray emission lasts more than 10 days. The event is a
hybrid, showing characteristics of both a GRB and a supernova, and leads
to the best observations yet exploring connections between these
Sept. 4, 2005: At a distance of 12.77 billion light-years, GRB 050904,
located in Pisces, is the farthest-known GRB at the time, the first of
many such Swift records.
May 9, 2005: GRB 050509B, in Coma Berenices, erupts with a flash of
gamma-rays that lasts just 0.03 second. Swift turns to the burst fast
enough to detect 11 X-ray photons, making this the first short burst
with a detected afterglow.
Dec. 17, 2004: Swift's first burst, in Crater, is eight-second-long GRB 041217.