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"
SOFIA's Mirror
22/10/2004
The candy-dish appearance of this high-tech astronomical mirror is striking. Made of a special glass ceramic material called Zerodur, it actually measures 2.7 meters across. The transparent surface has not yet received a reflective coating, so the weight-reducing internal honeycomb structure is visible with attractive blue and yellow tints provided by a protective tarp and background lighting. Recently unveiled, the telescope mirror is destined to fly on the Stratospheric Observatory For Infrared Astronomy (SOFIA). Since water vapor in Earth's troposphere tends to block infrared light, SOFIA will operate from a modified Boeing 747 jetliner at altitudes above 40,000 feet. As the largest airborne observatory in the world, SOFIA will explore a host of cosmic environments including sites of star birth and death, the formation of distant solar systems, and black holes in active galaxies.