First Message From NASA's Voyager 2 Sent Back From Space

40 years ago, NASA sent Voyager 2 out in space, effectively starting what would be the longest-running space mission yet. Outfitted with scientific instruments and launched 16 days before its twin Voyager 1, the spacecraft’s mission trajectory pointed it towards the outer skirts of our Solar System, aimed at reaching an elusive boundary that marks the edge of our sun’s territory and the actual start of interstellar space.

And now, it looks like Voyager 2 has accomplished what it set out to do, sending out a faint signal twelve billon miles from Earth for scientists to decode.

Beyond the Heliosphere

Originally, Voyager 2 launched more than two weeks before Voyager 1. However, because it took what’s essentially the “scenic route” by going around the solar system (even providing us our only images of Uranus and Neptune), it arrived at its destination six years behind its twin spacecraft, making it the second NASA craft to travel beyond the heliosphere. Defined as bubbles of supersonic charged particles streaming outwards from our sun, this so-called heliosphere marks the border between interstellar space and our solar system.

And now, after four decades, the spacecraft has sent back the most detailed look of what our solar system looks like from the edge, which surprised scientists because they didn’t know it would survive out in space for this long.

“We didn’t know how large the bubble was and we certainly didn’t know that the spacecraft could live long enough to reach the edge of the bubble and enter interstellar space,” Prof. Ed Stone, of the California Institute of Technology, said. Stone has been working on the mission since 1977, before Voyager 2 even launched.

Now decoded, the signal from the spacecraft shows that there is indeed a boundary where charged particles coming from the sun meet a cooler, interstellar wind. Previously, it was thought that the solar wind just gradually fades into the distance once it got far enough. Furthermore, data from Voyager 2 also provides some measurements, providing an image of how the heliosphere is shaped.

“It implies that the heliosphere is symmetric, at least at the two points where the Voyager spacecraft crossed,” Bill Kurth, a research scientist at the University of Iowa and a co-author on one of the studies, said. 

solar system As the Sun ages, scientists predict it may soon run out of fuel and start to expand. Pixabay