The Pale Blue Dot is a photograph of Earth taken by the Voyager 1 spacecraft at a distance of 3.7 billion miles away. The spacecraft had completed its primary mission and was passing Saturn, hurtling through space at 40,000 mph. Carl Sagan requested that the spacecraft turn around and take a photo of Earth, not for any scientific purpose, but as a sobering reminder of our planet’s insignificance. The resulting image inspired Sagan to write this now famous and breathtaking passage...