heliopause

[hee-lee-uh-pawz]

noun

Astronomy.

1. the boundary of the heliosphere.

heliopause

/ ˈhiːlɪəʊˌpɔːz /

noun

1. the boundary between the region of space dominated by the solar wind and the interstellar medium

heliopause

1. The region surrounding the solar system at which pressure from the outgoing solar wind equals the pressure from the interstellar medium (made up mostly of hydrogen and helium), and the solar wind can penetrate no further. It is considered to be the outer boundary of our solar system.

2. See more at solar wind

Word History and Origins

Origin of heliopause¹

First recorded in 1970–75; helio- + pause

Example Sentences

In 2012, Voyager 1 became the first human-made object to pass the heliopause frontier, where the fierce solar wind of subatomic particles yields to the force of other suns.

Read more on New York Times

In 2012 and 2019, NASA’s Voyager 1 and 2 spacecraft respectively broke through the heliopause, the boundary at which our sun’s sphere of influence gives way to the interstellar medium.

Read more on Scientific American

“The great circle in the sky,” as Brandt calls it, may be a region just beyond the heliopause where ions snared in a magnetic field spawn ENAs.

Read more on Science Magazine

Both probes have, in the past decade, entered “interstellar space” after breaching the heliopause.

Read more on Washington Times

One early guesstimate located the heliopause as close as Jupiter.

Read more on Scientific American