ABSTRACT
The discussion of cloud collapse due to J. Jeans (1902) has played a foundational role in ideas on star formation. The argument is basically that a large cloud of interstellar material can collapse when its internal pressure is insufficient to balance its self-gravitational attraction. For a given density and temperature, there is a critical mass beyond which gravitational contraction takes over as the predominating process until local fragmentation or star-formation disrupt the infall or change its character.
