Carl Sagan ponders a dream in which, as he explores the cosmos, he rediscovers Earth just as humans destroy themselves in an atomic coda. However common or uncommon intelligent life may be in our universe, there will never be anything quite like a human ever again after we've vanished. Not here, not anywhere.

Carl Sagan wrote the PBS series "Cosmos: A Personal Voyage" in correlation with Ann Druyan and Steven Soter. Thirteen episodes were aired in 1980, and are now available on DVD.