PEOPLE are fascinated by explosions, especially big ones. And they don鈥檛
come much bigger than the one picked up by the Italian-Dutch satellite BeppoSax
on 23 January. For a few tens of seconds the gamma-ray burster GRB 990123
radiated more energy than a million normal galaxies鈥攖hat鈥檚 around a
billion billion Suns. If the energy had been flung out in all directions instead
of in a narrow 鈥渏et鈥� of blisteringly hot material, the blast would have been
even bigger. Even so, only the most violent celestial events, such as the
collapse of a supermassive star or the swallowing of a neutron star by a black
hole, could release energy at such a mind-boggling rate.
Astronomers are still a long way from solving the long-standing puzzle of
gamma-ray bursters (see p 5). But it is sobering to reflect that these
cataclysmic explosions must be much commoner than they thought. Their beams will
usually be invisible to us because they don鈥檛 point our way.
January鈥檚 titanic explosion was in an unremarkable galaxy on the edge of the
visible Universe. If something like this happened in our Galaxy, it would make
the city-sized asteroid that finished off the dinosaurs seem as destructive as a
balloon on a stick.
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