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Stephan’s Quintet

Image credit: Barandi/NAU/Lowell Obs./NSF

The constellation Pegasus features a cluster of five galaxies whose violent interactions with each other have intrigued scientists for years. Known as Stephan’s Quintet, this galactic gathering is also a favored target of astrophotographers, but its greatest claim to fame is a cameo role in one of the most beloved and inspirational movies of all time.

Image credit: NASA

French astronomer Edouard Stephan discovered this eponymous cluster in 1877 at the Marseille Observatory in France. Scientists later classified it as a compact galaxy cluster, a group defined by its compactness, remoteness from other galaxies, and limited variability of brightness among its members. Stephan detected five visually adjacent members, though we know today that only four are physically associated and interacting. In 1982, Canadian astronomer Paul Hickson designated these four as HCG 92 (Hickson Compact Group 92) in his catalog of compact galaxy clusters. Located at a distance of about 300 million light years, the foursome is oriented diagonally in the accompanying picture. Because of the two dimensional nature of this image, the fifth member (to the lower left of the middle pair) appears adjacent to the others; in reality, it is “only” 40 million light years away. A sixth galaxy, at a distance similar to those of HCG 92, is visible on the far left of the image. Three of the HCG 92 galaxies are distorted, displaying odd-shaped loops caused by their intense gravitational interplay. Eventually, all four will likely either transform into elliptical galaxies or merge into a single large galaxy.

Thousands of astronomers and space enthusiasts have viewed or imaged Stephan’s Quintet, but millions of other people have unwittingly seen it in the opening scenes of the classic 1946 film, “It’s a Wonderful Life.” One minute and 57 seconds into the movie, a star field centered on Stephan’s Quintet (the view is rotated 90 degrees to the left) appears as various prayers for George Bailey are heard. As the scene zooms in, the voice of the head angel/God—represented by the middle pair of galaxies in Stephan’s Quintet—welcomes angel Joseph—represented by the non-interacting galactic member of the group. After a brief discussion, they summon Clarence Odbody, Angel 2nd Class, who arrives on the scene as a star. By the end of the movie, Clarence has saved George and earned his wings. Perhaps another scene could have been added with Clarence now in the form of a galaxy rather than a star, but that will have to wait for the remake.