APOD: July 10, 1998 - Interacting Galaxies (original) (raw)

Astronomy Picture of the Day

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July 10, 1998
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Explanation: This dramatic image of aninteracting pair of galaxies was made using the 1.5 meter telescope at theCerro Tololo Inter-American Observatorynear La Serena, Chile.NGC 1531 is the background galaxy with a bright core just above center and NGC 1532 is theforeground spiral galaxy laced with dust lanes. The pair is about 70 million light-years away in the southern constellationEridanus. Thesegalaxies lie close enough together so that each feels the influence of the other's gravity. The gravitational tug-of-war has triggeredstar formation in the foreground spiral as evidenced by theyoung, bright blue star clustersalong the 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.