“Just a few months after celebrating its 41st birthday, the Voyager 2 probe has left its familiar environs and entered interstellar space — only the second human-made object in history to do so, after Voyager 1 did it in 2012.
The moment they were waiting for arrived early last month, when Voyager 2 left what’s known as the heliosphere — the vast bubble of plasma and particles generated by the sun and stirred in solar winds. This bubble ends at a boundary called the heliopause, where the sun’s magnetic field peters out and solar winds give way to interstellar space.
By one definition, that also means Voyager 2 — now more than 11 billion miles from the sun — has achieved another, much simpler-to-say feat: leaving the solar system.
It’s not the only definition, though. And the JPL itself marks the end of the solar system at the edge of the sun’s gravitational influence, on the outer boundaries of the Oort Cloud. By that measure, the lab explained, both Voyager probes “have not yet left the solar system, and won’t be leaving anytime soon.”
“It will take about 300 years for Voyager 2 to reach the inner edge of the Oort Cloud,” it said, “and possibly 30,000 years to fly beyond it.”