<P> Star formation is the process by which dense regions within molecular clouds in interstellar space , sometimes referred to as `` stellar nurseries '' or `` star - forming regions '' , collapse and form stars . As a branch of astronomy , star formation includes the study of the interstellar medium ( ISM ) and giant molecular clouds ( GMC ) as precursors to the star formation process , and the study of protostars and young stellar objects as its immediate products . It is closely related to planet formation , another branch of astronomy . Star formation theory , as well as accounting for the formation of a single star , must also account for the statistics of binary stars and the initial mass function . </P>
where do most star formation occur in the milky way today
molecular clouds in interstellar space