NASA’s Voyager spacecraft pushed further out into space than any other mission before them. Voyager 1 and 2 visited Jupiter and Saturn, and Voyager 2 went on to travel to Uranus and Neptune. In 1990, after Voyager 2 completed its mission of visiting the outer planets, Carl Sagan encouraged NASA to have the Voyager 1 spacecraft to take a final picture of Earth, from a distance of more than 6 billion kilometers from Earth. The resulting image showed Earth as nothing more than a tiny spec, a “pale blue dot“. That was the name given to it by Carl Sagan, and it stuck.
Voyager 1 took this photograph in 1990, when it was approximately 40.5 astronomical units from Earth (6 billion km, or 3.8 billion miles). It was taken at a height of 32° above the plane of the ecliptic, using red, green and blue filters. Earth is the little dot circled in the image. The beams you see in the image are a glare from the Sun seen by Voyager 1’s camera.
Sagan wrote a book with the title “Pale Blue Dot”, and he gave a commencement address in 1996 reflecting on the image:
“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.”
We’ve written many articles about Carl Sagan for Universe Today. Here’s an article remembering Carl Sagan, and here’s Sagan’s personal influence on my own life. We also used the Pale Blue Dot image as one of our famous Where in the Universe contests.
If you’d like more info on Earth, check out NASA’s Solar System Exploration Guide on Earth. And here’s a link to NASA’s Earth Observatory.
We’ve also recorded an episode of Astronomy Cast all about planet Earth. Listen here, Episode 51: Earth.