Astronomers discover closest black hole to Earth 1,000 light-years away

Astronomers at the European Southern Observatory say they have discovered the closest black hole to Earth, just 1,000 light years away. A light year is the distance light travels in a year, 9.5 trillion km. It was found in a system called HR 6819, in the constellation Telescopium. The black hole, at least 4.2 times the mass of sun, is gravitationally bound to 2 stars in a so-called triple system.