largest supermassive black hole
Located in the Coma Cluster, about 300 million light years away from Earth, the orb is actually a distant view of the giant elliptical galaxy NGC 4889. At the center of that galaxy lies a sleeping giant: a supermassive black hole that is 21 billion times the mass of our sun. The size of a black hole can be estimated by its event horizon, or the distance from the center of the black hole at which nothing can escape its gravitational grasp.