Welcome to brain Stuff from How Stuff Works. Hey, brain Stuff, it's Christian Sager. On September five, nineteen seventy seven, NASA's historic Voyager one mission launched, joining its identical robotic twin Voyager two, on what would turn out to be a forty year odyssey through the Solar System and into interstellar space. Voyager two had launched more than two weeks earlier on August nineteen seventy seven, and both spacecraft completed the dazzling
grand tour of the Outer Solar System's planets. Voyager one has now left our sons heliosphere, becoming a bona fide interstellar probe and the most distant human made vehicle, and Voyager two is about to flirt with the outermost boundary of the Heliosphere the Helio Pause. But exploring interstellar space wasn't a mission objective back in nineteen seventy seven. Back then, the twin probes aim was to reveal the rich, diversity
and mystery of the Outer Solar System's planets. For Ed Stone, who has been project scientists for the Voyagers since nineteen seventy two, his favorite memory was the jaw dropping discovery of volcanoes on Jupiter's moon Io in nineteen seventy nine. He said the eruptions on Io were the first direct evidence of active volcanoes elsewhere in the Solar System, and
he wasn't wrong. Both Voyager one and two changed our perspective of our Solar System, revealing never before seeing details in planetary atmospheres and revealing new discoveries about interplanetary space. New insights to Saturn's beautiful rings were gleaned, and a huge diversity of moons swarming around the gas giants was revealed.
There are few more visceral science impacts on society than when in nineteen ninety Voyager one was commanded to turn around and capture an image of Earth from nearly four billion miles or six point four billion kilometers distant. This was at the request of Superstar astronomer and science communicator
Carl Sagan. In an interview with space dot Com, Stone estimated that both spacecraft only have about ten years supply of power left before the plutonium heat output dwindles, two levels that won't sustain any spacecraft instrumentation or critical subsystems. Though the Voyagers will eventually die, they continue to take data, and Voyager one is taking measurements of a very alien
region the interstellar medium. On August two thousand and twelve, NASA confirmed that Voyager one had officially left the heliosphere, speeding into interstellar space. Voyager two is traveling in a
different direction and has an encountered interstellar space. It The mysterious outermost regions of the Solar System have now been probed, and Voyager one was able to take measurements of the magnetic field and particle energies, important measurements that have allowed scientists a very privileged view of how our Son's magnetic field and solar wind particles interact with the space between
the stars. So, after four decades of exploration, two spacecraft built from nineteen seventies technology are still exploring, and a new generation of scientists are using them to carry out cutting edge research in a region of space that no
other robot that we know of has ever experienced. Even after their power supplies dwindle and the Voyagers lose communication with Earth, they will be silent interstellar emissaries for humanity, carrying the Golden records as shrines of the civilization that built these incredible machines should an extraterrestrial and elligence stumble
upon them and the eons to come. Today's episode was written by Ian O'Neill, produced by Dylan Fagan, and For more on this and other topics, please visit us at how stuff works dot com