Jul 31, 2013 9:40 AM by Stephen Bowers
In recent weeks, we told you about a comet named ISON. The comet, named after the International Scientific Optical Network where two Russian astronomers discovered ISON, is moving toward our solar system. Some scientists said the comet could be the "Comet of the Century." Now the tone may be changing.
Space.com says the comet has been hidden by the bright light from the sun and has not shown any signs of brightening since January. With the new month, the comet is expected to move from the constellation Gemini to Cancer. Throughout the month of August, Comet ISON is expected to become more visible from Earth, but with the brightness of the comet unchanged, some scientists worry the ice within the core of the comet, which melts to generate the tail of the comet, may already be melting as the comet approaches the sun.
ISON is expected to cross the "frost line" of our sun, which lies at a distance of between 230 million and 280 million miles away. At that distance away from the sun, the ice will not melt, but rather sublimate (which is conversion of water from solid to gas), which is a process that will help release gas and dust from the core of the comet.
Space.com has two possibilities in mind for the comet. The first is ISON completely disintegrates and never moves beyond the sun, which happened with Comet du Toit in December 1945. The comet could also fragment, but remain intact, and produce a bright tail as it releases dust and gas. Space.com says this happened with Great Comet of 1882 and comet Ikeya-Seki in 1965.
Space.com quotes Ignacio Ferrin, an astronomer at the University of Antioquia in Colombia, as saying ISON is already disintegrating. He pointed out a recent comet, C/2002 O4 Hönig, behaving similarly. It did not brighten for nearly two months before it disintegrated.
So, the "Comet of the Century" could turn out to be nothing more than a dud.