Interacting Galaxies

This dramatic image of an interacting pair of galaxies was made using 8-meter Gemini South
telescope at Cerro Pachon, Chile. NGC 1531 is the background galaxy with a bright core just
above center and NGC 1532 is the foreground spiral galaxy laced with dust lanes. The pair is
about 55 million light-years away in the southern constellation Eridanus. These galaxies lie
close enough together so that each feels the influence of the other's gravity. The gravitational
tug-of-war has triggered star formation in the foreground spiral as evidenced by the young,
bright blue star clusters along the upper edge of the front spiral arm. Though the spiral galaxy
in this pair is viewed nearly edge-on, astronomers believe the system is similar to the face-on
spiral and companion known as M51, the Whirlpool Galaxy.