A black hole is an astronomical object whose gravity is so strong that nothing—even light—can escape from within its event horizon. It forms when a massive star’s core collapses or through other processes, and may have an accretion disk of infalling matter that emits radiation. Supermassive black holes at galaxy centers influence stellar orbits, and mergers produce gravitational waves.
Source: nasa.gov
22/07/2015
If gamma-rays were raindrops a flare from a supermassive black hole might look like this. Not so gently falling on the Fermi Gamma-ray Space Telescope from June 14 to June 16 the gamma-ray photons, with energies up to 50 billion electron volts, originated in active galaxy 3C 279 some 5 billion light-years away. Each gamma-ray "drop" is an expanding circle in the timelapse visualization, the color and maximum size determined by the gamma-ray's measured energy. Starting with a background drizzle, the sudden downpour that then trails off is the intense, high energy flare. The creative and calming presentation of the historically bright flare covers a 5 degree wide region of the gamma-ray sky centered on 3C 279.