Sagan reflects on the future of humanity and the question of "who speaks for Earth?" when meeting extraterrestrials. He discusses the very different meetings of the Tlingit people and explorer Jean-Francois de La Perouse with the destruction of the Aztecs by Spanish conquistadors, the looming threat of nuclear warfare, and the threats shown by destruction of the Library of Alexandria and the murder of Hypatia. The episode ends with an overview of the beginning of the universe, the evolution of life, and the accomplishments of humanity and makes a plea to mankind to cherish life and continue its journey in the cosmos. The Cosmos Update notes the preliminary reconnaissance of planets with spacecraft, the fall of the Berlin Wall and the end of apartheid in South Africa, and measures towards the reduction of nuclear weapons.
Astronomers are laying the groundwork to locate a new planet for the human race to inhabit, and the more alien worlds they discover and encounter, the more they unmask the mysterious and truly destructive nature of the cosmos.
Scientists on the BICEP and Planck missions are attempting to solve a mystery about the earliest moments of our universe, by searching for patterns in the cosmic microwave background. If successful, the missions will help to answer the biggest question anyone can ask: how did our universe begin?
From the mission that saw Pluto for the first time to the Mars rovers, a new breed of explorers are risking their careers, and even their lives, to lead humanity to worlds we have never seen and tackle the mysteries of life itself.