Learn about Earth Day founder Gaylord Nelson (1916–2005) and how environmental disasters of his day inspired the creation of Earth Day in 1970. On December 7, 1972, Apollo 17 astronauts captured a now ...

When those conditions are just right, the Earth, sun, and moon line up. This diagram shows how that looks ... turning the sky dark in the middle of the day. During totality only the sun's ...