Astronomers have discovered that every 175 years the outer planets of our solar system, Jupiter, Saturn, Uranus and Neptune are aligned on the same side of the sun. In the mid-1960s NASA scientists were aware that this rare geometric arrangement would allow a spacecraft on a particular flight path to swing from one planet to the other without the need for large onboard propulsion systems.
In the early 1970s engineers at the Jet Propulsion Laboratory in California began to work on two identical spacecraft, Voyager 1 and Voyager 2. As originally designed, the Voyagers were to conduct close-up studies of Jupiter, Saturn, Saturn’s rings and the larger moons of the two planets.
NASA placed an ambitious message aboard Voyagers 1 and 2, a kind of time capsule intended to communicate a story of our world to extraterrestrials. The contents of the record were selected by a committee chaired by Carl Sagan of Cornell University. On the record are 115 images and a variety of natural sounds such as the wind, surf, thunder, birds, whales, and other mammals. To this they added several musical selections from different cultures and spoken greetings in 55 languages. The hope is that someday an alien culture will find and play the recording. But it will be 40,000 years before Voyager spacecraft will be close to another planetary system.
By December 1981 the two Voyager spacecraft had successfully accomplished their objectives at Jupiter and Saturn. Flybys of the two outermost planets proved possible — and irresistible — to mission scientists. As the two spacecraft flew across the solar system, they were reprogrammed via radio communications to aim for the outer planets. Eventually, Voyager 1 and Voyager 2 explored all the outer planets, including their rings and magnetic fields as well as 48 of their moons.
The information returned to Earth revolutionized planetary science, helping resolve key questions while raising intriguing new ones about the origin and evolution of our solar system. The two Voyagers took well over 100,000 images. The last imaging sequence involved turning Voyager 1 back to face Earth at the request of Carl Sagan. This showed Earth and six other planets as sparks in a dark sky lit by a single bright star, the sun. Another image is a portrait of Earth, tiny at that distance, caught in a sunbeam. Sagan wrote the following about the now famous photograph.
“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… It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world.
To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”
Jamie Kinscherff is a longtime resident of central Texas, retired from a 45-year career as a custom guitar maker. A Master Naturalist since 2003, he’s an amateur astronomer serving as the Outreach Coordinator for Wimberley Valley Dark Sky, as well as the Environmental Studies teacher at Blanco River Academy. Jamie is a Member of Wimberley Arts. org
