In 1990, the Voyager 1 spacecraft was about six billion kilometres from home, heading out of the solar system. At the urging of astronomer Carl Sagan, NASA turned its camera around for one last look back.

Earth appears as a speck less than a pixel wide, suspended in a band of sunlight scattered inside the camera's optics.

Sagan later wrote about it in his book Pale Blue Dot, in a passage that has become one of the most quoted pieces of science writing ever: on that dot, he said, is everyone you love, everyone you know, everyone you ever heard of — every king and peasant, every hero and coward, every saint and sinner in the history of our species.

It may be the smallest subject in this gallery. It is also the biggest.