Today's Image

Greenish Comet ISON on its way

Posted by
Eleanor Imster
and
October 1, 2013
Another look at Comet ISON, this one from September 28, 2013. In this shot, the comet has a greenish color, possibly indicating that it has crossed the
Photo by Michael Jaeger. Used with permission. Visit’s Michael Jaeger’s comet gallery.

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.

Click here a monthly Comet ISON viewing guide.

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Posted 
October 1, 2013
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Today's Image

Eleanor Imster

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About the Author:
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. She and her husband live in Tennessee, where they enjoy guitar playing and singing. They have 2 grown sons.

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