Peculiar Arp 87

Explanation: A cosmic bridge of stars, gas, and dust stretches for over 75,000 light-years and joins this peculiar pair of galaxies cataloged as Arp 87 . The bridge is strong evidence that these two immense star systems have passed close to each other and experienced violent tides induced by mutual gravity . As further evidence, the face-on spiral galaxy on the right, also known as NGC 3808A, exhibits many young blue star clusters produced in a burst of star formation. The twisted edge-on spiral on the left (NGC 3808B) seems to be wrapped in the material bridging the galaxies and surrounded by a curious polar ring . While such interactions are drawn out over billions of years, repeated close passages should ultimately result in the merger of this pair of galaxies into a larger single galaxy of stars. Although this scenario does look peculiar, galactic mergers are thought to be common, with Arp 87 representing a stage in this inevitable process . The Arp 87 pair are about 300 million light-years distant toward the constellation Leo. The prominent edge-on spiral at the far left appears to be a more distant background galaxy and not involved in the on-going merger.