Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2007 January 24
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A Comet Tail Horizon
Credit & Copyright: Marco Fulle (Stromboli online)

Explanation: What's happening over the horizon? Many a sky enthusiast who thought they had seen it all had never seen anything like this. To the surprise of many Northern Hemisphere observers, the tail of Comet McNaught remained visible even after the comet's head set ahead of the Sun. What's more, visible were bright but extremely rare filamentary striae from the comet's expansive dust tail. The cause of dust tail striae are not known for sure, but are possibly related to fragmentation of comet's nucleus. The last comet to show prominent striae was Comet Hale-Bopp in 1997. Pictured above, the tail of Comet McNaught was caught just after sunset last Friday above the Carnic Alps of northern Italy.

Tomorrow's picture: creek drank the cradle

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