Stephen Hawking sets three volunteers a series of fun challenges to show them how to think like a genius - and find out how likely it is that aliens exist.

Originally released by Public Broadcasting Service (U.S.), 2016. Streaming video file encoded with permission for digital streaming by Infobase on February 13, 2017.

Are We Alone? --(2:45) -- Scale of the Galaxy -- (2:44) -- Galileo Galilei -- (2:03) -- Stars in the Milky Way -- (3:45) -- Giordano Bruno -- (1:44) -- Planet and Stars to Scale -- (3:09) -- Planet Osiris -- (2:12) -- First Planet Spotted -- (2:00) -- Kepler Telescope -- (3:57) -- Goldilocks Zone -- (2:30) -- Generating Heat Through Friction -- (3:48) -- Moon Orbiting the Gas Giant -- (2:59) -- High Probability of Alien Life -- (1:29) -- Sound of the Universe -- (1:54) -- Listening to Space -- (2:04) -- Giuseppe Cocconi and Philip Morrison -- (3:06) -- The Great Filter -- (3:45) -- Fragility of Life -- (3:44) -- Conclusion: Are We Alone? -- (3:07) -- Credits: Genius By Stephen Hawking: Are We Alone? -- (0:19).