Astronomy Picture of the Day

Explanation: What makes comet tails so colourful? This photograph of Comet Hyakutake was taken the night of April 18th and highlights different components of the tail. The gold and red tail features are dust, made predominately of little bits of rock and carbon. The dust tail shines by reflecting sunlight. Extending past the dust tail is the comet's ion tail, shown here glowing in blue. The ion tail is composed mostly of ions of water, carbon monoxide, and cyanogen. The ion tail glows by emitting light when elections re-combine with electrically charged ions to make uncharged molecules. The photograph was taken just north of Kansas City, Missouri, USA.