26:59
Is Anybody Out There?
What are the odds that life exists elsewhere in the universe, and what are we doing to find out? Topics in this video range from the meaning of the Drake Equation and assumptions being used to narrow the vast field of stars in which scientists are s...
52:09
Who's Afraid of a Big Black Hole?
Black holes are by definition invisible, and there is no scientific theory that can adequately explain them. Nevertheless, researchers are determined to unravel the mysteries of black holes in the hope of answering some of the universe’s most pres...