Comet Encke fishtailing across the sky

In this delightful time-lapse image from NASA's Astronomy Picture of the Day, the tail of short-period comet Encke can be seen flailing about in the solar wind.

Go to http://apod.nasa.gov/apod/image/0710/enckeRipoff_movie_short.gif for the animation. The comet is small (it orbits the sun about every 3 years, so has lost a lot of its mass over time), but the sequence is quite fascinating – normally, a comet is so slow-moving that you need to watch carefully for hours or days, to see any change. On this occasion, the wonders of time-lapse have saved you the wait.