For most of recorded history, and even before, mankind measured time by the rotation of the earth. This image shows that rotation in the form of star trails centered around Polaris, the north star. The trails are formed as the earth, and the camera riding on it, spins on its axis under the stars.
This image could not have been made without the use of Photoshop (or other editing program) in that it is a set of twelve ten minute exposures, combined to make this one image. This is an area where film still has an advantage over digital. Digital cameras have significant noise in long exposures, whereas film has no such problem (film does have reciprocity failure however, Google it if you're curious). The limit for my camera, a Canon 20D is between 10 and 15 minutes.
An artifact of shooting digital is the choppiness of the trails. Since there is a finite delay between each image there are gaps in the trails. Another advantage to film.
The images which make up this composite were taken at the Black Forest Star Party.