It's starting to increasingly look like Comet ISON, which at one time was viewed as potentially one of the most spectacular comets of the last hundred years (see last article), may not even survive long enough to make its' rendevous with the Sun on November 28th of this year.
There had always been a concern among astronomers and cometary experts that this might happen, since Comet ISON will be coming so close to the Sun, but there had been cautious optimism that the cosmic visitor might survive its' encounter with the sun and provide us with an impressive show in the sky. Part of the reason for this optimism was the fact that Comet ISON, at between 1,000 and 4,000 meters in diameter (about 1 - 2 miles) appeared to be large enough to avoid the fate of smaller comets, which tend to disintegrate when passing the Sun at the distance ISON is expected to pass (about 730,000 miles, slightly less than the diameter of the Sun itself). However, evidence has begun to surface in the last few days that this might not be so. According to Ignacio Ferrin, an astrophysicist at the University of Antiquia in Medlin, Columbia, light signatures from ISON, which has just passed the orbit of Mars, indicate that it may be about to break up. According to Ferrin, comets generally get brighter and more luminous the closer they get to the sun. However, the light curve for ISON slowed down and remained nearly constant in its' brightness, even as the comet got closer to the sun. According to Ferrin, this behavior is similar to that of four other comets that have broken up before reaching perihelion. Also, the fact that this is the first time that Comet ISON has visited the inner reaches of the solar system may be playing a role in its' possible demise, since it hasn't had time to develop a protective layer as have other comets that have made repeated visits, such as Comet Halley.
While this is very disappointing news, it must be remembered that the latest observational evidence indicates that Comet ISON has NOT yet broken up, so there still remains some hope that it may remain intact at least long enough for it to reach the Earth's orbit and possibly even the sun itself. We may still see it in the morning sky in a little over a month or so, even though it may not be as spectacular as once hoped. That we may be privileged to see it at all is a wonder all in itself.