Voyager 1 Close to Interstellar Space

Launched in 1977

Ed Stone cannot say when the Voyager-1 spacecraft will leave the Solar System, but he believes the moment is close.

The latest data from this extraordinary probe, reported in this week's Science journal, suggests it is surfing right on the very edge of our Sun's domain.

The particles streaming away from our star have reduced to a trickle at its present location, 18.5 billion km from Earth.