The Sun · Spaceflight
Heliopause
Say it: HEE-lee-uh-pawz IPA: /ˈhiːliəpɔːz/ noun
Heliopause: The boundary separating solar-wind plasma from the surrounding interstellar plasma.
The Sun sends a stream of charged particles outward. The heliopause marks the outer boundary of that solar-wind region, where it meets the interstellar environment.
- Example
- The spacecraft's particle measurements indicated a crossing of the heliopause.
- Why astronomers use it
- It helps define how the Sun's plasma environment interacts with the galaxy around it.
- Tiny cosmic connection
- Crossing the heliopause does not mean escaping the Sun's gravity.
Observatory The Sun Spaceflight
Where to check it
- NASA: Basics of Space Flight glossary (opens in a new tab)
- Wikipedia: Heliosphere (opens in a new tab)
Written for Cool Moon Facts in its own words; the sources cover the same idea in more depth.