heliosphere

American  

[hee-lee-uh-sfeer] / ˈhi li əˌsfɪər /

noun

Astronomy.

1. the region around the sun over which the effect of the solar wind extends.

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heliosphere British  

/ ˈhiːlɪəʊˌsfɪə /

noun

1. the region around the sun outside of which the sun's influence is negligible and interstellar space begins

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heliosphere Scientific  

/ hē′lē-ə-sfîr′ /

1. The large, roughly elliptical region of space around the Sun through which the solar wind extends and through which the Sun exerts a magnetic influence. The heliosphere extends well beyond the orbits of the planets, and its shape and extent fluctuate with changes to the solar wind and other influences.

2. ◆ The boundary between the heliosphere and interstellar space is known as the heliopause.

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Etymology

Origin of heliosphere

First recorded in 1970–75; helio- + -sphere

Example Sentences

By combining these observations, SPO will not only capture images of the poles for the first time but also connect them to the flows of plasma and magnetic energy that shape the heliosphere.

From Science Daily • Oct. 14, 2025

Voyager 1 exited the heliosphere in 2012, the first earthly object to reach interstellar space.

From Science Magazine • May 23, 2024

The heliosphere extends out to about 100 to 120 times further than Earth's distance to the sun.

From Reuters • Aug. 24, 2023

But it no longer needs to wait, and the mission has resumed data transmissions from beyond the solar system’s heliosphere.

From New York Times • Aug. 4, 2023

Voyager 2 and its twin Voyager 1 are the only spacecraft ever to operate outside the heliosphere, the protective bubble of particles and magnetic fields generated by the Sun.

From BBC • Aug. 1, 2023