What happened to comet ISON?
By Phyllis Burton Pitluga
So far Comet ISON has been a non-dusty comet that has displayed a dimmer blue-green gas tail. If, after the furious vaporizing near the sun on November 28, more grains of rocky-sandy material got released, we may see a classic white fanlike tail. The three-mile (five-kilometer) wide “ice ball” may become a showpiece in our early to mid December dawn sky. Look to the east-southeast low above the horizon an hour before sunrise. This comet passes closest to Earth on December 26 but is farther from the sun, its source of reflecting light.
All you really need to see a great comet will be your eyes. Binoculars or a telescope will let you see more details in the cloud of vapor coming off of the comet nucleus. Look for two tails, the blue-green gas tail and a white dust tail. The tails will be pointing away from the sun because there is a constant outflow of protons from the sun pushing outward the vaporized gases and dust off of comets. This outflow from the sun is called the solar wind.
Comet ISON came from the outermost reaches of our Solar System where its primordial gases have remained unchanged in the deep freeze of space since the Solar System formed four and a half billion years ago. This is a chance to learn more about the chemistry of our outer solar system from its earliest time. Was this outermost realm icy and dusty or was it just icy? The tails will tell.
The two Russian amateur astronomers who discovered Comet ISON in September of 2012 were using the International Scientific Optic Network. Thus, from the initials of the telescope network came the name Comet ISON.