No human object has left the solar system
The core idea stands, but key numbers or details have changed.
TaughtVoyager 1 is heading out of the solar system and will eventually cross into interstellar space, sometime in the distant future.
NowVoyager 1 crossed the heliopause in August 2012, confirmed by NASA in September 2013. Voyager 2 followed in 2018. Both are now in interstellar space.
What actually happened
The boundary in question is the heliopause: the point where the solar wind streaming off the Sun is finally stopped by the pressure of the interstellar medium. Nobody knew exactly how far out it was, and the crossing was announced only after a year of argument about the data.
The confirming evidence was elegant. Voyager 1's plasma instrument had failed decades earlier, so it could not directly measure the density of the medium it was flying through. Then in 2012 the Sun emitted a coronal mass ejection, and when that wave reached Voyager 1 in 2013 it made the surrounding plasma ring like a bell. The frequency of that ringing revealed a density about forty times higher than in the solar wind, exactly what interstellar space should look like.
A caveat worth keeping: the spacecraft are past the heliopause, but they are still inside the Sun's gravitational reach. The Oort cloud extends far beyond them, and Voyager 1 will not clear it for roughly another 30,000 years.
Newsletter
Get new weekly revisions
Sources
- NASA: Voyager 1 in interstellar spacescience.nasa.gov
- NASA JPL: Voyager mission statusvoyager.jpl.nasa.gov
Who was taught this
Still standard through 2013, so anyone who finished school between 1950 and 2013 learned the earlier version.