(Last edited: Friday, 26 May 2023, 5:25 PM)




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Short Definition:

The Heliosphere is the extended layer of the Sun consisting of its magnetosphere, astrosphere and atmosphere. It has a bubble-like shape, covering the entire Solar System. 

Detailed Definition:

The Heliosphere in physics terms is a cavity that is formed by the Sun in its neighbourhood. It binds our solar system together, like an atmosphere on Earth binds life on the surface. It also produces weather conditions like the ones on Earth, but the weather happens on a larger, solar system scale. 

The Heliosphere consists of plasma, particles and magnetic fields that interact with the space environment, producing what we call space weather. It is also a shield, without which we probably would not exist, as it protects our planet from cosmic rays, particles created far away in space. Without the existence of a heliosphere, our living cells would be continuously bombarded, causing damage.

As this wave of solar wind wanders away from the Sun, at some point it reaches termination shock, where its speed suddenly drops from even 700 km/s. Beyond the termination shock lies the heliosheath, the outer region of the heliosphere, where solar wind becomes denser and hotter as it presses towards wind in interstellar space. The boundary between it and the interstellar wind is called heliopause, the pressure of both of the winds stays in balance there. 


helio- +‎ -sphere

helio - from Ancient Greek ἥλιος (hḗlios).

sphere - from Ancient Greek σφαῖρα (sphaîra, “ball, globe”)

Sample Sentence(s):

Voyager 1 travelled through the heliosphere and encountered heliopause in 2015. 

As the heliopause marks the boundary between the matter originating from the Sun and matter originating from the rest of the galaxy, the spacecrafts that left the heliosphere are travelling through interstellar space.

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Die Heliosphäre





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