On November 5, 2018, NASA’s Voyager 2 joined its sister aircraft Voyager 1 beyond the heliosphere, ‘the protective bubble of particles and magnetic fields created by our Sun’. Considered a ‘watershed moment in our exploration of space’, five new research papers have been published in the journal Nature Astronomy documenting what’s happened since the spacecraft crossed the boundary and raged against the dying of the light.
As per NASA’s Jet Propulsion Laboratory, Voyager 2’s findings will help ‘paint a picture of this cosmic shoreline, where the environment created by our Sun ends and the vast ocean of interstellar space begins’.
As told to IFLScience, NASA astrophysicist Jeffrey Hayes said:
This is a watershed moment in our exploration of space: we have for the first time left the confines of ‘home’ and are taking our very first tentative steps into the interstellar space – the Milky Way galaxy of which we are a part. That’s an amazing distance to come in only 62 years, since the launch of the first satellite. Who knows what the next 62 will bring?
Each of the research papers revolves around the spacecraft’s findings, compiled from its five operating instruments: a magnetic field sensor, two instruments to detect energetic particles in different energy ranges and two instruments for studying plasma (a gas composed of charged particles). But just what is the heliosphere? Hayes offered an explanation, described it as a ‘somewhat porous boundary’.
Inside is the space we live in, which is the very extended influence of the Sun and the solar wind that it generates, and outside is a region that is not under that same influence. Both Voyagers found this to be the case. The original model was that the solar wind would just gradually fade away until one was in the interstellar medium; clearly that’s not the case.
The heliopause acts as a somewhat porous boundary that only allows some particles to traverse it. Because we have only very recently passed through it – in 2012 with Voyager 1, and now with Voyager 2, there are still a lot of aspects of this we don’t understand. Discussing further exploration possibilities, Hayes added:
While the Voyager 2 has yet to enter undisturbed interstellar space, the probes offer a groundbreaking illustration of how the ‘Sun interacts with the stuff that fills most of the space between stars in the Milky Way galaxy’.