Comet Hale Bopp viewed from Pazin in Istria/Croatia, 29 March 1997. Photo Credit: Philipp Salzgeber
The twitterverse is starting to light up with rumors about a new comet, C/2012 S1 (ISON). It’s projected to get “extremely close” to the sun in November 2013, at which point it may do what comets often do when affected by the sun’s proximity—disintegrate (see the fate of last year’s Comet Elenin). If the ISON comet makes it around the bend, however, it may attain a significantly negative apparent magnitude. A comet with a magnitude of -15 wouldn’t just be the brightest object in the night sky (a full moon has a magnitude of -13 or so), it would be one of the two brightest objects in the day sky. It’s not going to outshine the sun (magnitude around -26), but it would still be visible to the naked eye.
Skymania has a nice summary of the possibilities for the comet.
