This week marks 48 years since the Sept. 5, 1977, launch of NASA’s Voyager 1 spacecraft from Cape Canaveral, Florida, to study Jupiter and Saturn up close. Nearly a half-century later, Voyager 1 and its twin Voyager 2 are still exploring, only now they’re in the outer reaches of our solar system.
To celebrate, NASA’s Jet Propulsion Laboratory is sharing an archival video of the June 6, 1990, press conference following the conclusion of the mission’s planetary explorations. In the briefing, mission representatives reveal Voyager’s “Solar System Family Portrait,” a mosaic comprising images of six of the solar system’s eight planets, taken by Voyager 1 on Feb. 14, 1990, when the spacecraft was beyond the orbit of Neptune — about 3.7 billion miles (6 billion kilometers) from the Sun.
Captured by Voyager, the “Solar System Family Portrait” was shared during this 90-minute NASA news conference in Washington. Joining Voyager Project Scientist Ed Stone is science communicator Carl Sagan, whose description of the iconic “Pale Blue Dot” image of Earth would evolve into a famous essay.
Each planet is a mere pinprick of light, taking up only about one pixel. In the press conference, Voyager science team member and renowned science communicator Carl Sagan dubs the image of Earth the “Pale Blue Dot” and shares a few lines of what would eventually become an essay about the humbling image.
“This is where we live — on a blue dot,” Sagan said. “That’s where everyone you know and everyone you have heard of and every human being who ever lived lived out their life. It’s a very small stage in a great cosmic arena. And again, just speaking for myself, I think this perspective underscores our responsibility to preserve and cherish that blue dot, the only home we have.”
Voyager 1 launched two weeks after its twin, Voyager 2. The pair’s primary mission included close flybys of Jupiter and Saturn, as well as some of their moons. Although they weren’t the first spacecraft to visit the two gas giants, their discoveries were many.
“This is where we live — on a blue dot,” Sagan said, describing this Voyager image in which Earth appears as a pixel-size speck. “That’s where everyone you know and everyone you have heard of and every human being who ever lived lived out their life. It’s a very small stage in a great cosmic arena.”
Voyager 2 went on to fly by Uranus in 1986 and Neptune in 1989 on an extended mission that yielded other key findings. (The spacecraft remains the only one to visit those planets.) The press conference provides a chance to watch longtime Voyager project scientist Ed Stone recap those and other discoveries — and to look into the future of the spacecraft, which had already begun their interstellar mission, with the two probes continuing on their trajectories away from the Sun and out of the solar system.
The primary goal of the new Voyager Interstellar Mission was to find the boundary of the heliosphere, a bubble of charged particles and magnetic fields created by the Sun, and to sample interstellar space beyond it. This boundary at the time was at an unknown distance and is undetectable by telescopes.
“The space between the stars, interstellar space, is filled with a very dilute gas called the interstellar medium, and each star blows a bubble into that gas,” Stone said. “We don’t know how large the Sun’s bubble is. ... The boundary of this bubble may be 100 times as far as the distance from the Earth to the Sun. No one knows!”
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It turned out that the heliosphere was even farther than Stone’s guess. At the start of the interstellar mission, Voyager 1 was about 40 times farther from the Sun than Earth is, or 40 astronomical units, and Voyager 2 was about 31 times farther from the Sun than Earth is, or 31 astronomical units. When Voyager 1 exited the heliosphere and entered interstellar space in 2012, it was about 11 billion miles (18 billion kilometers) from the Sun, or 122 astronomical units. Voyager 2, traveling slower and in a different direction, exited the heliosphere in 2018 at about the same distance, 119 astronomical units from the Sun. The Voyagers also found that the boundary region shields the solar system from about two-thirds of cosmic rays that are present in nearby interstellar space.
Today, Voyager 1 and 2 are about 15 billion miles (25 billion kilometers) and 13 billion miles (21 billion kilometers) from Earth, respectively.
For more information about NASA’s Voyager mission, visit:
https://science.nasa.gov/mission/voyager
Pale Blue Dot by Carl Sagan
Courtesy of Ann Druyan
© Democritus Properties, LLC. 1994