the.com/heliopause
where the sun finally stops arguing with the rest of the galaxy.
means the boundary where the sun's solar wind loses its shoving match against interstellar gas and stops pushing outward.
from from helio- (sun) plus pause, coined to mark the point where solar wind pressure equals interstellar medium pressure — the sun's exhale finally runs out of breath.
voyager 1crossed it in 2012, still hasn't left the sun's gravity
distanceroughly 120 astronomical units from the sun
shapelopsided, like a windsock, not a sphere