Comet ISON is this year’s most anticipated comet. Today (October 1) ISON will sweep closely past the Red Planet Mars. It’ll be on its way to a Thanksgiving Day (November 28) encounter with the sun, and hopefully to a good showing in Earth’s night sky.
Note the greenish color of ISON in Michael’s photo. As it nears the sun, the comet is becoming more active. Jets beginning to spew more vigorously from the comet’s nucleus contain both cyanogen and diatomic carbon, which both glow green when illuminated by strong sunlight.
Eleanor Imster has helped write and edit EarthSky since 1995. She was an integral part of the award-winning EarthSky radio series almost since it began until it ended in 2013. Today, as Lead Editor at EarthSky.org, she helps present the science and nature stories and photos you enjoy. She also serves as one of the voices of EarthSky on social media platforms including Facebook, Twitter and G+. She and her husband live in Tennessee and have two grown sons.