Comet ISON Approaches

 by John Bortle

June 13, 2013

Newly discovered comets are always a bit mysterious and confounding in how they develop. That’s especially true for new comets that become active early, promising great things while they’re still far from the Sun. In these cases, predictions of future glory often fall flat.

So what can we expect from Comet ISON (C/2012), now approaching amid great expectations? It will swing close by the Sun at the end of November and climb up the dawn sky in December. Some of the media have been billing ISON as “the comet of the century.” Is there a chance that this won’t be an embarrassment?

The excitement arises from the remarkably close Sun graze that the comet will perform at its perihelion on November 28th. It will fly less than one solar diameter past the Sun’s surface, with the dusty ice of its nucleus broiling violently. Despite the unknowns, past performances by sungrazing and sun-skirting comets allow us to make a reasonable estimate of what’s in store... the rest/image