Knowing without Seeing --The Science of Black Holes

With their relentlessly powerful gravitational pull, black holes suck in anything that comes near them: not even light can escape. They were first discovered not by direct observation but through the human power of logical analysis. However, the very existence of black holes was the subject of heated debate for about half a century. This episode introduces the latest research into the strange physical phenomena caused by black holes and an experimental method for directly viewing these invisible celestial bodies. It is the story of dedicated scientists in a quest to see the "unseeable".