 a black hole that's more massive than a garden variety one created by a collapsing star, but smaller than the supermassive black holes that are found in the center of galaxies. Now in the journal Nature, researchers report they've found one using Hubble Space Telescope images of a nearby star cluster, which is like a cloud made of millions of stars. They found seven stars at the center of this cluster that were moving unusually fast, apparently whizzing around a black hole