After more than 40 years, the Voyager 2 spacecraft has crossed the boundary that marks the start of interstellar space.
NASA said on Tuesday that the spacecraft had entered the interstellar medium,...the region of space outside the boundary produced by wind streaming from the Sun.
Researchers says Voyager 2 detected abrupt differences in plasma density and magnetic particles upon crossing the heliopause.
It's just the second man-made object ever to depart the solar system after its twin the Voyager 1 entered interstellar space in November last year.
The Voyager twins were launched in 1977, and both are now traversing the Milky Way's interstellar medium.