About 300 million light-years from Earth is a group of five galaxies known as Stephan’s Quintet (or Hickson Compact Group 92). The name ‘quintet’ is a bit of a misnomer. Four of the galaxies form the first compact galaxy group ever discovered. But the fifth group member is actually a foreground galaxy about seven times closer to Earth than the rest of the group.

First seen by (and named after) French astronomer Édouard Jean-Marie Stephan in 1877 at the Marseille Observatory, Stephan’s Quintet is thought to be involved in a cosmic dance that will likely end with the galaxies merging. Visible in the Pegasus constellation, the group is the most studied of all the compact galaxy groups.