The domain of the Sun's influence is called the heliosphere: The Voyagers are approaching the edge of this enormous balloon of charged particles thrown out into space by our star
Humankind's most distant emissaries are flying through a turbulent sea of magnetism as they seek to break free of our Solar System.
Nasa's Voyager probes, which were launched in 1977, are now approaching the very edge of our Sun's influence, more than 14 billion km from Earth; and they are still returning data.
That information has allowed scientists to build a better picture of what conditions are like in the zone where matter blown out from our star pushes up against interstellar space.
Computer modelling based on the Voyager insights suggests the edge of our Solar System is a froth of activity, like "an agitated jacuzzi", said Eugene Parker from the University of Chicago, US.
Magnetic field lines carried in the "wind" of material coming off our star are breaking and reconnecting.
This process is sculpting the wind into discrete bubbles that are many tens of millions of kilometres wide.