55 Years Ago: Mariner 2 First to Venus: “In 1962, Mariner 2 completed the first successful close-up observations of another planet when it flew by Venus… Since it orbited closer to the Sun, most scientists assumed Venus was the warmer of the two, and some believed its climate was similar to Earth’s tropics. A young scientist named Carl Sagan, however, proposed that the known high concentration of carbon dioxide in Venus’ atmosphere created a runaway greenhouse effect, leading to extremely high temperatures at the surface.”
55 Years Ago: Mariner 2 First to Venus: “In 1962, Mariner 2 completed the first successful close-up observations of another planet when it flew by Venus… Since it orbited closer to the Sun, most scientists assumed Venus was the warmer of the two, and some believed its climate was similar to Earth’s tropics. A young scientist named Carl Sagan, however, proposed that the known high concentration of carbon dioxide in Venus’ atmosphere created a runaway greenhouse effect, leading to extremely high temperatures at the surface.”