 Interstellar cloud, an interstellar cloud is generally an accumulation of gas, plasma, and dusting power and other galaxies. Put differently, an interstellar cloud is a denser than average region of the interstellar medium, fissure of the matter and radiation that exists in the space between the star systems 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-I region, or molecular, which are referred to simply as molecular clouds, or sometimes dense clouds. Neutral and 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.