Black Hole
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
APODs including "Black Hole"
At Last, GLAST
13/06/2008
Rising through a billowing cloud of smoke, this Delta II rocket left Cape Canaveral Air Force Station's launch pad 17-B Wednesday at 12:05 pm EDT. Snug in the payload section was GLAST, the Gamma-ray Large Area Space Telescope, now in orbit around planet Earth. GLAST's detector technology was developed for use in terrestrial particle accelerators. But from orbit, GLAST can study gamma-rays from extreme environments in our own Milky Way galaxy, as well as supermassive black holes at the centers of distant active galaxies, and the sources of powerful gamma-ray bursts. Those cosmic accelerators achieve energies not attainable in earthbound laboratories. GLAST also has the sensitivity to search for signatures of new physics in the relatively unexplored high-energy gamma-ray regime.