Dr. Carl Sagan has guided the viewer through many episodes of Cosmos, and has explained many of the more difficult concepts pertaining to the workings of the universe. In Cosmos, Episode 13: Who Speaks for Earth?, he makes use of the special effects that have illuminated previous shows to take the viewer back 15 billion years to the Big Bang, and marks the major steps leading to the modern-day view of space. He tells the story of Hypatia of Alexandria, one of the first women scientists, who became a martyr. To conclude, Dr. Sagan delivers a monologue on the responsibility of mankind not just to earth, but to the cosmos, the source of our being.
by Alice Day synopsis