On Valentine's Day 1990, NASA's Voyager 1 spacecraft snapped what would become one of the most iconic images ever taken: a view of Earth from 3.7 billion miles (6 billion kilometers) away.

Earth Day is held on April 22 with this year’s being the 55th anniversary of the first in 1970. It began during a time of great public protest in this country due to the Vietnam War, the Nixon ...

F or most of human history, Earth has been known as the “Pale Blue Dot,” a term popularized by astronomer Carl Sagan when ...