This video shows Hubble observations of Arp 116, a pair of galaxies in the constellation of Virgo. It is made up of M60, a large elliptical galaxy, and a smaller, bluer spiral galaxy, NGC 4647. It has long been unclear whether the two galaxies are actually interacting, or whether they simply appear close together from our distant vantage point. However, detailed studies of Hubble pictures suggest that the pair are beginning to experience tidal forces.
More information and download-options:http://spacetelescope.org/videos/heic1213b/
NASA, ESA. Music: R. Vreeland (disasterpeace.com)