On Valentine’s Day in 1990, a love affair with humans’ home planet was rekindled with a picture taken from 3.7 billion miles away. The picture, which was taken from beyond the great gas giant Neptune, captured the Earth in relation to the nearby planets in the solar system. The mind-bogglingly insignificant sight of the planet in the image led to the Earth’s affectionate nickname of “The Pale Blue Dot.”

The image was taken by NASA’s Voyager 1 spacecraft as it rotated back toward the Earth. It has been dubbed a “family portrait,” as it captured the unique arrangement of Uranus, Neptune, Saturn, Jupiter, Earth, and Venus from its unprecedented vantage point. The missing members of the solar system in the picture were due to lighting issues: Mars and dwarf planet Pluto were both too dim, and Mercury was too close to the sun to stand out.

The image was the spontaneous brainchild of the late Carl Sagan, not part of the original plan for Voyager’s mission. Some worried that pointing the spacecraft’s sensitive camera in the direction of the Sun would damage the delicate equipment, but Sagan argued that it was more important to get a sense of humanity’s place in the cosmos. With the support of NASA administrator Richard Truly, the iconic image was finally taken.

Voyager 1 is still travelling through the depths of space, and, amazingly, still sending back recorded data to the Earth. It is now the furthest manmade object from the Earth, at a distance of about 130 AU. The spacecraft launched in 1977, and is now making its way through interstellar space. “We had no idea how long the spacecraft would last,” said Ed Stone, project scientist for the Voyager mission, based at the California Institute of Technology, Pasadena.

The image had such a great impact on Sagan that he titled one of his books Pale Blue Dot, published in 1994. “Look again at that dot,” he wrote. “That’s here. That’s home. That’s us.”