关于这张图
Galaxy Evolution Explorer observation of Stephan's Quintet and the nearby galaxy NGC 7331. Blue represents far ultraviolet, and red near ultraviolet. Stephan's quintet is an interacting group of galaxies. Close inspection of the group (lower center-right) shows blue regions of recent star formation associated with streamers of gas (tidal tails) created by the interaction. NGC 7331 shows prominent star formation in spiral arms. http://photojournal.jpl.nasa.gov/catalog/PIA04925
