There is an old astronomer’s quip about comets being like cats: In that they have tails and do exactly as they please.
Astronomy is at times a very exact science, and at others it can be a ‘shrug your shoulders and admit you don’t know’ science. At times engineers can argue about the time it takes a Space Probe to get to another planet in our solar system and have it figured out to nearly the second over a distance of hundreds of millions of miles. That is an example of the former moments. Comets are an example of the latter.
Comet ISON was discovered last year and after a few checks of its orbit it was stated that it might be the brightest comet in our sky, ever. The talk was that it might put the impressive Hale-Bopp to shame. “Comet of the Century” was a term bandied about in the media. Pretty aggressive marketing given that we are only in the year 2013.
Now, however, some folks are not so certain.
Comets are fragile things. They are essentially balls of dirty ice & frozen gases surrounded by a tiny atmosphere of gas. They are not asteroids made of rock. This means they can be a little bit on the fragile side. Comet ShoeMaker-Levy demonstrated this in when it broke apart due to tidal forces from Jupiter in 1992. In 1994 the fragments struck Jupiter.
ISON, however, is not likely to hit any planets, but it is expected to get very close to the sun. EXTREMELY close to the sun – less than 1 million miles. To put this in perspective the Earth is 93,000,000 miles from the Sun.
Being this close to the sun could easily cause the comet to break apart. If it does so it will not likely make a very impressive show. This has sadly happened many times in the past. Comet Elenin in 2011 was much vaunted as a ‘Doomsday Comet’ by some internet crazies but broke apart before given a decent show.
Should the comet ISON survive, however, it will be one hell of an impressive show. This image is a projection of how it might look.
We look forward to it, and hope ISON survives its close encounter with the sun.