On July 19, 2013, Cassini slipped into Saturn's shadow and turned to image the planet, seven of its moons, its inner rings - and, in the background, our home planet, Earth.
Wave at Saturn
It wasn't the first time Earth had been photographed from interplanetary distances. Voyager 1's Pale Blue Dot image (shown) is the most famous example. But Cassini's 2013 picture was the first time in history human beings knew exactly when their home world was being photographed.
We asked Earthlings to wave back at Saturn as the image was taken. Thousands of people around the world responded.
San Diego Comic-Con International.
Eddington Astronomical Society of Kendal. Image courtesy of S. White.
NASA's Jet Propulsion Laboratory.
Science Center of Iowa. Image credit: SCI
Many shared their waves on social media with the hashtag #waveatsaturn.
Cassini was able to capture 323 images in just over four hours. This final mosaic uses 141 of those wide-angle images.This image spans about 404,880 miles (651,591 kilometers) across.
Four planets were captured in Cassini's image: Saturn, Venus, Mars and Earth.
The busy Saturn system.
"While Earth is too small in the images Cassini obtained to distinguish any individual human beings, the mission put together this collage to celebrate all your waving hands, uplifted paws, smiling faces and artwork." - Linda Spilker, Cassini project scientist