The M60-UCD1, discovered by NASA’s Hubble Space Telescope in 2013, is one of the smallest known galaxies. But now the space agency has discovered that the dwarf galaxy is harboring a “monster” black hole. The diameter of M60-UCD1 is about 300 light years – just 1/500th of our galaxy’s width. However, it is packed with 140 million stars, which also makes it one of the densest galaxies. For...