In August of 2007, astronomers found a gigantic hole in the universe. This round shape empty space, stretching nearly a billion light-years across, is devoid of any matter such as galaxies, stars, and gas, and neither does it contain the strange and mysterious dark matter, which can be detected but not seen. The large void in the Constellation Eridanus appears to be improbable given current cosmological models. A radical and controversial theory proposes that it is a "universe-in-mass black hole"