Interstellar Medium

(Last edited: Friday, 22 September 2023, 6:16 PM) (n.d.). ESO - The Planet, the Galaxy and the Laser. 1999- 2008 ESO. OPIA/Paranal/phot-33a-07.tif.html (n.d.). ESO - The Planet, the Galaxy and the Laser. 1999- 2008 ESO. OPIA/Paranal/phot-33a-07.tif.html

Short Definition:

The interstellar medium (ISM) is a composition of radiation and matter which occurs between star systems, which are compositions of stars orbiting each other. The medium is usually created from various gasses, mostly hydrogen and helium. This matter is a filler between the stars.

Detailed Definition:

The interstellar medium (ISM) is a region filled with gas and dust in between stars. The medium is created when a star dies. As the star collapses into itself, it releases huge amounts of energy and matter at high velocity and high temperature. When this mix encounters patches of interstellar gas, the visible nebulas of interstellar medium are created. The gas is ionized, and space dust blocks certain light waves which. Contrary to common belief, space is not completely empty and is not a full vacuum but is filled with matter such as gas and space dust. The interstellar medium is impactful in formations it is in. Stars which are positioned in the denser areas of ISM supply it with matter and energy through stellar winds or supernovae (the explosion of a star). The inter-influence of stars and ISM formations helps scientists determine the lifespan of given star formations.


This phrase is a conjunction between the words 'interstellar' and 'medium'. The word 'interstellar' comes from combining the prefix 'inter' from Latin for "between" and the word 'stellar' from Latin 'stellaris' meaning "pertaining to a star". The word 'medium' from Latin medium "the middle, midst, center; interval"

Sample Sentence(s):

1. The interstellar medium can be visible with long exposure astrological photography.
2. The Pillars of Creation are a beautiful example of the interstellar medium.


French: milieu interstellaire

German:  interstellares Medium

Italian: mezzo interstellare

Polish: ośrodek międzygwiazdowy

Swedish: interstellärt medium

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