Comparison of Earth's atmosphere to the hostile conditions of Venus. Blues for a Red Planet: Humanity's fascination with Mars.
Sagan details the development of modern science through the work of figures like Kepler, Newton, and Huygens , as well as ancient thinkers from the Library of Alexandria . Carl Sagan Unser Kosmos (1982, 276 S , Text) pdf
Speculation on interstellar communication. Comparison of Earth's atmosphere to the hostile conditions