It was not part of the plan.
On February 14, 1990, the Voyager I spacecraft was beyond Neptune, 3.7 billion miles from the Sun, when it turned and took a series of photos of the planets of our Solar System. Known as the Family Portrait series, the images were not part of the original mission plan. The idea originated with Carl Sagan, renowned planetary scientist and member of the Voyager Imaging Team.
The photo of Earth, which Sagan dubbed the “pale blue dot,” had the greatest impact—a representation of the fragility and isolation of our only home.
Sagan narrates the video above with a famous passage from Pale Blue Dot: A Vision of the Human Future in Space, his 1994 book inspired by the image.