NASA’s longest-running mission, the Voyager spacecraft, has scaled the limits of our solar system. While Voyager 1 reached interstellar space in 2012, its sister probe trailing six years behind, Voyager 2, followed it out of the solar system nearly a year ago, becoming the second spacecraft to ever enter the space between the stars. As the plasma-measuring instrument on Voyager 1 had been damaged, it could not gather data about the transition for the solar system to the interstellar space.
But Voyager 2 exited the solar system with all its instruments intact and had a complete set of data. Scientists shared the findings for the first time via five papers published in the journal, Nature Astronomy. And turns out, there are mysterious extra layers between the solar system’s bubble and interstellar space.
Just beyond the edge of the solar system, solar winds interact with interstellar winds containing gas, dust and charged particles originating from supernova explosions millions of years ago, and turn back on themselves. The outermost boundary of the Sun’s protective bubble, heliopause envelopes the solar system and is the place where the Sun’s magnetic field and galactic magnetic fields meet. Voyager 2 detected these solar winds leaking out of the heliopause into the galaxy, upstream up to a billion miles.
The new boundary layers indicate there are stages in the transition from our solar bubble to the space beyond, which scientists previously had an idea of but didn’t understand. This transition is usually marked by plasma change that Voyager 1’s instruments had difficulty measuring. Now that we have Voyager 2’s data, we finally know that boundaries between the solar system and interstellar space might not be as simple as scientists once thought.
What’s more? The new results also showed that compared with Voyager 1, Voyager 2 experienced a much smoother transition from the heliopause to a strong new magnetic field beyond the solar system. This still remains a puzzle for astrophysicists to understand the complicated relationship between the edges of the galactic space and our solar system. The scientists hope to continue studying these boundaries over the next five years before the Voyager probes run out of fuel.