How It Works

Space mystery: Can rectangular galaxies really exist?

rectangular galaxy

The laws of orbital mechanics mean that stars always follow elliptical (stretched circular) orbits under the influence of gravity, so in large groups they form either flattened disc-like spirals or ball-shaped ellipticals. The sharp corners of a rectangle should be impossible, but nevertheless astronomers have found several galaxies with apparently rectangular features. For example, LEDA 074886 in the constellation of Eridanus is a compact, rectangular galaxy embedded in a nearby galaxy cluster. The big question is whether its shape is a long-lived structure or brief coincidence – astronomers who have studied it with the giant Japanese Subaru telescope think the latter is more likely, and that a collision and merger between two could have scattered the outlying stars into their current box-like distribution, triggering a wave of starbirth at the new centre.