PBS
Pbs: Origins: Where Are the Aliens?
Was there ever life on another planet? Could there be life on another planet again? What makes the Earth support life? This article investigates these questions in depth.
NASA
Nasa: Jet Propulsion Laboratory: Planet Quest: Exoplanet Exploration
Constellation of articles, images, diagrams, posters, videos, and more on the subject of the search for planets, particularly Earth-like planets, outside our solar system.