what is this quoted term means?
A molecular cloud, sometimes called a stellar nursery, is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen
Molecular cloud
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen (H).
where does the gas and dust to form stars originate from "molecular clouds"
wiki:25697159
Molecular cloud [SEP] Introduction
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen (H). This is in contrast to other areas of the interstellar medium that contain predominantly ionized gas. Molecular hydrogen is difficult to detect by infrared and radio observations, so the molecule most often used to determine the presence of H is carbon monoxide (CO). The ratio between CO luminosity and H mass is thought to be constant, although there are reasons to doubt this assumption in observations of some other galaxies.