A Galaxy Grouping in 2D and 3D: Stephan’s Quintet

In 1877, Edouard Stephan discovered a tight visual grouping of five galaxies located in the constellation Pegasus. The galaxies of Stephan’s Quintet are both overlapping and interacting, and have become the most famous among the compact groups of galaxies. Astronomers have long known that four of the galaxies (all of which are yellowish-white in this video) form a physical group in space, while the fifth (bluish) is a foreground galaxy. In addition, a sixth galaxy (yellowish-white and on the far left) is likely to be part of the physical grouping. Hence, this 2D quintet that is a 3D quartet may actually be a 2D sextet that is a 3D quintet. ... Read More | Share it now!