M79, a globular cluster about 41,000 light years from Earth in the constellation Lepus, is a gravitationally bound group of about 150,000 stars that was discovered in 1780 by Pierre Méchain and added to Charles Messier’s famous catalog. William Herschel, using a more powerful telescope, first called it a “globular star cluster.” Globular clusters typically orbit the core of the Milky Way and can contain more than a million stars. M79 may have a more unusual history than most given its location in the opposite direction from the core. It may be a captured cluster from a dwarf galaxy in the process of merging with the Milky Way or it may have simply formed in a region with a higher density of stars. Either way, the Hubble Space Telescope provides a stunning view.
The Hubble Space Telescope imaged a distant cluster of galaxies that was found by ESA’s Planck satellite, which detected distortions in the cosmic background radiation caused by the cluster’s gravity. Some five billion light years from Earth, the cluster’s members appear as a swarm of red-shifted galaxies, along with an arc of bluish light caused by gravitational lensing.