1. interstellar matter
Wikipedia definition
2. Interstellar mediumIn astronomy, the interstellar medium (or ISM) 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.
Read “Interstellar medium” on English Wikipedia
Read “星間物質” on Japanese Wikipedia
Read “Interstellar medium” on DBpedia


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