Editing Interstellar cloud (section)

{{short description|Accumulation of gas, plasma, and dust in space}}
[[File:Carved by Massive Stars.jpg|thumb|A small part of the [[emission nebula]] [[NGC 6357]]. It glows with the characteristic red of an [[H II region]].<ref>{{cite web |title=Carved by Massive Stars |url=http://www.eso.org/public/images/potw1334a/ |work=ESO Picture of the Week |publisher=[[European Southern Observatory]] |access-date=13 September 2013}}</ref>]]

An '''interstellar cloud''' is an accumulation of [[gas]], [[Plasma (physics)|plasma]], and [[cosmic dust]] in [[galaxies]]. Put differently, an interstellar cloud is a denser-than-average region of the [[interstellar medium]], the [[matter]] and radiation that exists in the [[Interstellar space|space]] between the [[star system]]s in a galaxy. Depending on the [[density]], [[size]], and [[temperature]] of a given cloud, its [[hydrogen]] can be neutral, making an [[H I region]]; ionized, or plasma making it an [[H II region]]; or molecular, which are referred to simply as [[molecular cloud]]s, or sometime dense clouds. Neutral and [[Ionization|ionized]] clouds are sometimes also called ''diffuse clouds''. An interstellar cloud is formed by the gas and dust particles from a [[red giant]] in its later life.