Comment Re:not to rain on anyone's parade.... (Score 2) 271
To make things more ambiguous (along the GPs point), "Interstellar space": Voyager 1 is 17 light hours from us (so under 0.2% the distance to Proxima Centauri). Not sure when or how they decided interstellar space starts before the Oort Cloud (1 ly away).
A justification could be made that astronomically-scaled systems may have plenty of in-between objects that are far enough away to be considered interstellar space. However, when defining an interstellar comet: "At present, an interstellar comet can only be detected if it passes through our solar system, and could be distinguished from an Oort cloud comet by its strongly hyperbolic trajectory (indicating that it is not gravitationally bound to the Sun)." - so if interstellar comets are not interstellar unless they originate from outside the Oort Cloud, I don't see why we consider Voyager 1 even remotely approaching interstellar space when it's still so far from the Oort Cloud.
And reversibly, due to Voyager 1's known one-way trajectory out/away from the Sun, it could be considered not gravitationally bound to the Sun. So is or will be interstellar if not destroyed before.
Anyway, I think 'exiting the heliosphere' is the point of the article. 'Interstellar space' is a sensationalist term in the headline.