The Cosmic Horseshoe is a cosmic illusion. It consists of a massive galaxy encircled what appears to be a bright blue ring. The ring is actually a more distant galaxy. The gravity of the closer galaxy acts as a lens, magnifying and distorting the view of the background object. The foreground galaxy contains a supermassive black hole that may be the heaviest detected: 36 billion times the mass of the Sun. [NASA/ESA-Hubble]
Find out more in our radio program entitled Biggest Black Hole.