heliopause
HEE-lee-uh-pawz
Definition
The theoretical boundary where the solar wind is stopped by the interstellar medium and the pressure of the Sun's magnetic field is balanced by the pressure of the surrounding galactic environment.
Etymology
The word is a compound of the Greek 'helios' (Sun) and the English 'pause' (a temporary stop or cessation).
In the news
The article uses heliopause to define the physical boundary Voyager 1 crossed in 2012, marking its entry into interstellar space and differentiating it from the ongoing gravitational influence of the Sun.
NASA has calculated, to the precise second, when Voyager 1 will be exactly one light-day from Earth: 2:16 a.m. on 18 November 2026, at a distance of 16,094,799,096 miles — a number that would have been science fiction when the probe launched in 1977
Read the full article ↗Space Daily