Messier 87 is a supergiant elliptical galaxy in the constellation Virgo. It has about 12,000 globular clusters—compared to the 150 to 200 orbiting the Milky Way—and a jet of energetic plasma that originates at the core and extends at least 4,900 light-years. One of the brightest radio sources in the sky, it is a popular target for both amateur and professional astronomers. The French astronomer Charles Messier discovered the galaxy in 1781, and catalogued it as a nebulous feature while searching for objects that would otherwise confuse comet hunters. About 53.5 million light-years from Earth, M87 is the second brightest galaxy within the northern Virgo Cluster. Unlike disk-shaped spiral galaxies, M87 has no distinctive dust lanes. Instead, it has an almost featureless ellipsoidal shape typical of most giant elliptical galaxies, diminishing in luminosity away from the center. It has a supermassive black hole at its core, powering an active galactic nucleus. (Full article...)