That the Voyager 1 spacecraft is closer than ever to entering interstellar space should be front-page news.
I grew up next door to NASA’s Jet Propulsion Lab in La Canada Flintridge. I remember when the Voyager 1 and 2 spacecraft were launched in 1977 carrying the famous Golden Records with “messages from Earth.” Many were the planetary surprises of the ‘80s: beautiful, up-close pictures of Saturn, Jupiter, Uranus and Neptune and their multitude of moons; active volcanism on Jupiter’s moon Io (the first time active volcanoes were seen anywhere else in our solar system); and Uranus’s rings, to name a few.
From four billion miles away, in 1990 Voyager 1 shot our solar system’s first portrait and its last of Earth. Our planet’s image is a mere “pale blue dot” of light, only .12 pixel in size. Thank you, Dr. Carl Sagan, for giving us some perspective.
JPL announced this week that Voyager 1 is in the final area it has to cross before reaching interstellar space, which is likely just a few months to a couple years away. Scientists call this new region the “magnetic highway” because it’s where the sun’s magnetic field lines are connected to interstellar magnetic field lines.
This connection allows lower-energy charged particles that originate from inside our heliosphere (the giant bubble of charged particles the sun blows around itself) to zoom out while allowing higher-energy particles from outside to stream in. The direction of these magnetic field lines is predicted to change when Voyager 1 breaks through to interstellar space. (From JPL’s Dec. 3, 2012 press release).
Why should we care? Just ask Dr. Ed Stone, Voyager project scientist (since 1972), Caltech physics professor and a former director of JPL. Science is learning new things about nature and expanding our frontier of knowledge. Voyager 1 and 2 spacecraft are humanity’s first interstellar probes, the first to go outside the region that has material from our own star. “When you go places no spacecraft has been before, you are almost bound to learn something that no one knew before,” says Stone.
JPL scientists are listening to the Voyager spacecraft, which is a remarkable feat in itself. With a 20-watt transmitter on the spacecraft from over 11 billion miles away, every bit of data that left the spacecraft 17 hours ago tells them something new that that they didn’t know before, says Stone. Powered by radioisotope thermoelectric generators, the two Voyager spacecraft are expected to continue communicating with us at least through 2020 and probably longer.
Think we’ll be saying, “Where were you the day Voyager 1 broke through to the space between the stars?”
The Voyager spacecraft were built by JPL, which continues to operate both. Launched on Sept. 5, 1977, Voyager 1 is the most distant human-made object, at about 11 billion miles away from our sun.
Launched Aug. 20, 1977, Voyager 2 is the longest operating spacecraft, past or present. It is about 9 billion miles away from our sun. JPL is a division of the California Institute of Technology. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington.
For more information about the Voyager spacecraft:
To see and listen to Dr. Stone talk about the Voyager program: http://voyager.jpl.nasa.gov/v_inter_cable.mov
Editor's note: This post has been changed. An earlier version mistated Voyager 1's travel distance.