heliopause

American  

[hee-lee-uh-pawz] / ˈhi li əˌpɔz /

noun

Astronomy.

1. the boundary of the heliosphere.

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heliopause British  

/ ˈhiːlɪəʊˌpɔːz /

noun

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

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heliopause Scientific  

/ hē′lē-ə-pôz′ /

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

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Etymology

Origin of heliopause

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.

From 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.

From Scientific American

The solar wind would run farther before sputtering to a stop at the heliopause, where the hot, wispy plasma of our heliosphere gives way to the cold, dense plasma of interstellar space.

From Science Magazine

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

From Washington Times

Almost 20 years passed before one of the Voyagers finally made it to the heliopause.

From Scientific American