A two-phase model of this phenomenon was proposed by Field, Goldsmith, and Habing; that model was extended to athree-phase model by McKee and Ostriker with the discovery that this phenomenon also included a hot component withtemperatures around 10 to the 6th Kelvin. Gamma ray signals from the decay of aluminum-26 are the most important probesof radioactivity in this material. Structure formation in this material is driven primarily by Jeans collapse and shocks to thismaterial caused by ejecta result in the formation of Herbig-Haro objects. The 
A two-phase model of this phenomenon was proposed by Field, Goldsmith, and Habing; that model was extended to athree-phase model by McKee and Ostriker with the discovery that this phenomenon also included a hot component withtemperatures around 10 to the 6th Kelvin. Gamma ray signals from the decay of aluminum-26 are the most important probesof radioactivity in this material. Structure formation in this material is driven primarily by Jeans collapse and shocks to thismaterial caused by ejecta result in the formation of Herbig-Haro objects. The primary radio signal from this material is the21-centimeter line produced by hyperÂfine transitions in its main constituent. The solar wind's termination shock demarcatesthe boundary between the heliosphere and the region of space occupied by this material, which mostly comprises neutral hydrogen,HII clouds, and dust grains. For 10 points, identify this matter dispersed throughout the Milky Way which permeatesthe space between objects like the Sun and Alpha Centauri.
A two-phase model of this phenomenon was proposed by Field, Goldsmith, and Habing; that model was extended to athree-phase model by McKee and Ostriker with the discovery that this phenomenon also included a hot component withtemperatures around 10 to the 6th Kelvin.
interstellar medium