New Year’s brings the yearning for survival
The year 2013 wasn’t a great one for the environment. Sparing the details: Nature’s calamities didn’t let up, humans’ relentless exploitation of natural resources didn’t either. Amid this discouraging chronicle, one story never made the headlines. It’s a small story, but it reaches farther into the future than any other story during 2013, even climate change. Call it “One giant leap past the Sun.”
On Sept. 12, 2013, NASA announced that Voyager 1, a spacecraft launched in 1977, had left the solar system and entered interstellar space. Scientists established the crossover date as Aug. 25, 2012, the first time any human-made craft has made contact with the galaxy—a monumental event.
The year-long effort to find out when the event happened was itself a small miracle of science. Just as the Earth is surrounded by an atmosphere, the Sun is surrounded by a magnetized bubble filled with charged particles. Called the “heliosphere,” it encompasses the solar system. The particles within it are called “plasma,” aka “solar wind.” At the outer edge of the heliosphere is the “heliopause,” a border region scientists knew little about.
To mark the time when Voyager crossed this frontier, they’d originally counted on an instrument that would directly measure a sharp jump in plasma density, since the interstellar wind is known to be 50 times as dense as the solar wind. But the plasma detector had failed in 1980.
Scientists also thought the crossover would be marked by a change in the direction of the magnetic field as Voyager left the magnetic field of the Sun. But Voyager’s magnetometer showed, instead, that the heliopause somehow aligns the interstellar and heliospheric magnetic fields to create a “magnetic highway,” still a mystery.
At last, scientists turned to a third instrument that measured changes in general electrical activity around Voyager over time; tracking back these data, they finally confirmed a plasma spike. The evidence was indirect, but convincing. Voyager had gone galactic.
It doesn’t matter that Voyager’s signal is now 20 times weaker than a digital watch, and will die in 2025. Dead or alive: Voyager is an ambassador. In 40 millennia (42,013), it will pass within 1.6 light years of another star, Gliese 445. After that, it will orbit the Milky Way far longer than the life of our Earth or Sun. For any extraterrestrial life-form that finds it, it bears a Golden Record with images and sounds from our environment, our civilization, including these words from President Carter: “This is a present from a small, distant world….We are attempting to survive our time so we may live into yours. We hope, someday, having solved the problems we face, to join a community of galactic civilizations.”
Precisely how the Voyager story will play out in Milford, Connecticut and every other community on Earth, no one knows. But we’ll find out…someday. Just as Christmas brings the reassurance of Love, New Year’s brings the yearning for survival, a Future. Happy New Year.