Very soon, space probe Voyager 1 will be probing outside our solar system.
According to the team at NASA, the probe is sending back some very strange data from its position 11 billion miles from home, meaning the Voyager 1 is drifting through the border between the heliosphere (the bubble where charged particles from the sun stream outward), and the border’s environment isn’t what scientists expected.
In 2004, the probe crossed what’s called the termination shock, the border where the sun’s particles stop streaming in an orderly manner and start bouncing around in all directions, and after some starts and stops, the solar wind slowed to zero. This, the researchers were prepared for. What’s unexpected is how magnetic field changed; instead of weakening, it increased in intensity. While the lack of solar wind suggested that Voyager 1 had already left the heliosphere, the uptick in magnetic field strength proved that it’s still crossing through the borderlands, known as the heliosheath.
Researchers expect the magnetic field to switch direction once Voyager 1 is truly free of the heliosphere, but another surprise would be par for the course according to Voyager project scientist Edward Stone. “We’ve come to expect the unexpected from Voyager, ” he says.
While many of the Voyager’s instruments have stopped working since its 1977 launch, its geothermal generator is expected to power the remainder of the instruments until 2027, plenty of time to get the very first read-outs of what it’s like outside our solar system’s little bubble.