On Valentine's Day, 1990, 3.7 billion miles away from the sun, the Voyager 1 spacecraft takes a photograph of Earth. The picture, known as Pale Blue Dot, depicts our planet as a nearly indiscernible speck roughly the size of a pixel.
Launched on September 5, 1977, Voyagers 1 and 2 were charged with exploring the outer reaches of our solar system. It passed by Jupiter in March of 1979 and Saturn the following year. The gaps between the outer planets are so vast that it was another decade before it passed by Neptune and arrived at the spot where it was to take a series of images of the planets, known as the "Family Portrait" of our solar system.
Of the Family Portrait series, Pale Blue Dot was certainly the most memorable. The furthest image ever taken of Earth, it lent its name to popular astronomer Carl Sagan's 1994 book. Sagan, who advised the Voyager mission and had suggested the photo, wrote the following: "Look again at that dot. That's here. That's home. That's us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every "superstar," every "supreme leader," every saint and sinner in the history of our species lived there—on a mote of dust suspended in a sunbeam."
Voyager 1's journey continues. In 1998, it became the most distant human-made object in space, and on August 25, 2012, it left the furthest reaches of the sun's magnetic field and solar winds, becoming the first man-made object in interstellar space.