Definitions for interstellar medium
in·ter·stel·lar medi·um

Princeton's WordNetRate this definition:0.0 / 0 votes

1. interstellar mediumnoun

   interstellar space including streams of protons moving from the stars

WikipediaRate this definition:0.0 / 0 votes

1. Interstellar medium

   In astronomy, the interstellar medium (ISM) is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space. The energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation field. The interstellar medium is composed of multiple phases distinguished by whether matter is ionic, atomic, or molecular, and the temperature and density of the matter. The interstellar medium is composed, primarily, of hydrogen, followed by helium with trace amounts of carbon, oxygen, and nitrogen. The thermal pressures of these phases are in rough equilibrium with one another. Magnetic fields and turbulent motions also provide pressure in the ISM, and are typically more important, dynamically, than the thermal pressure is. In the interstellar medium, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm3 (1 million molecules per cm3). In hot, diffuse regions of the ISM, matter is primarily ionized, and the density may be as low as 10−4 ions per cm3. Compare this with a number density of roughly 1019 molecules per cm3 for air at sea level, and 1010 molecules per cm3 (10 billion molecules per cm3) for a laboratory high-vacuum chamber. By mass, 99% of the ISM is gas in any form, and 1% is dust. Of the gas in the ISM, by number 91% of atoms are hydrogen and 8.9% are helium, with 0.1% being atoms of elements heavier than hydrogen or helium, known as "metals" in astronomical parlance. By mass this amounts to 70% hydrogen, 28% helium, and 1.5% heavier elements. The hydrogen and helium are primarily a result of primordial nucleosynthesis, while the heavier elements in the ISM are mostly a result of enrichment (due to stellar gravity and radiation pressure) in the process of stellar evolution. The ISM plays a crucial role in astrophysics precisely because of its intermediate role between stellar and galactic scales. Stars form within the densest regions of the ISM, which ultimately contributes to molecular clouds and replenishes the ISM with matter and energy through planetary nebulae, stellar winds, and supernovae. This interplay between stars and the ISM helps determine the rate at which a galaxy depletes its gaseous content, and therefore its lifespan of active star formation. Voyager 1 reached the ISM on August 25, 2012, making it the first artificial object from Earth to do so. Interstellar plasma and dust will be studied until the estimated mission end date of 2025. Its twin Voyager 2 entered the ISM on November 5, 2018.

ChatGPTRate this definition:0.0 / 0 votes

1. interstellar medium

   The interstellar medium (ISM) is the matter and radiation that exist in the space between the star systems in a galaxy. This includes gas in various phases, dust, cosmic rays, and magnetic fields. The interstellar medium plays a crucial role in the cycle of star formation and evolution.

WikidataRate this definition:0.0 / 0 votes

1. Interstellar medium

   In astronomy, the interstellar medium is the matter that exists in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, dust, and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space. The energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation field. The interstellar medium is composed of multiple phases, distinguished by whether matter is ionic, atomic, or molecular, and the temperature and density of the matter. The thermal pressures of these phases are in rough equilibrium with one another. Magnetic fields and turbulent motions also provide pressure in the ISM, and are typically more important dynamically than the thermal pressure is. In all phases, the interstellar medium is extremely dilute by terrestrial standards. In cool, dense regions of the ISM, matter is primarily in molecular form, and reaches number densities of 106 molecules per cm³. In hot, diffuse regions of the ISM, matter is primarily ionized, and the density may be as low as 10−4 ions per cm³. Compare this with a number density of roughly 10²² molecules per cm³ for liquid water. By mass, 99% of the ISM is gas in any form, and 1% is dust. Of the gas in the ISM, 89% of atoms are hydrogen and 9% are helium, with 2% of atoms being elements heavier than hydrogen or helium, which are called "metals" in astronomical parlance. The hydrogen and helium are a result of primordial nucleosynthesis, while the heavier elements in the ISM are a result of enrichment in the process of stellar evolution.

Matched Categories

1. • Interstellar Space

How to pronounce interstellar medium?

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How to say interstellar medium in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of interstellar medium in Chaldean Numerology is: 8

2. Pythagorean Numerology

   The numerical value of interstellar medium in Pythagorean Numerology is: 2

Examples of interstellar medium in a Sentence

1. Andrea Dupree:

   All stars are losing material to the interstellar medium, and we don't know how this material is lost, we know that other hotter luminous stars lose material and it quickly turns to dust making the star appear much fainter. But in over a century-and-a-half, this has not happened to Betelgeuse. It's very unique.

2. Don Gurnett:

   Think of a cold front that forms when a very cold air mass comes down to the U.S. from Canada, here we find a very hot plasma mass coming outward from the sun that encounters the cold plasma in the interstellar medium. It does not surprise me that a sharp boundary forms.

References

1. ^ Princeton's WordNet
   http://wordnetweb.princeton.edu/perl/webwn?s=interstellar medium
2. ^ Wikipedia
   https://en.wikipedia.org/wiki/Interstellar_Medium
3. ^ ChatGPT
   https://chat.openai.com
4. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=interstellar medium