How did life originate and evolve here on Earth? What form could life take elsewhere – and where else could life survive beyond our planet? These are questions that scientists called astrobiologists tackle every day. By using space telescopes, doing laboratory experiments and studying extreme environments on Earth, astrobiologists hope to uncover new insights about what it means to be “life” and get more clues to the ultimate question: Are we alone in the universe? Mary Voytek, head of NASA’s astrobiology program, discusses in this episode.