First a meteor exploded over Russia, followed closely by an
asteroid fly-by. Now, two comets are expected to put on a naked-
eye spectacle for sky watchers in the Northern Hemisphere. Up
first is Comet Pan-STARRS, which gets its funky name from the
telescope credited with discovering it in June 2001: the
Panoramic Survey Telescope & Rapid Response System in Hawaii.
The comet is already visible through telescopes in the Southern
Hemisphere, and it should swing into view over the Northern
Hemisphere beginning around March 8. It's hard to predict
exactly how bright Pan-STARRS will be, but you should be able to
see it without binoculars or telescopes, said Don Yeomans of
NASA's Near-Earth Object Program. It should be about as bright
as the stars in the Big Dipper. "There is a chance that it will
be a little brighter than this, but likewise, it might not get
quite that bright," said Karl Battams of the Naval Research Lab.
Part of the brightness will depend on how close Pan-STARRS gets
to the sun. Comets are made up