gravitational instabilityA situation in which an object's self-gravity exceeds opposing forces such as internal gas pressure or material rigidity, and the object collapses. For a gas, gravitational instability sets in when the mass is greater than a certain critical value known as the Jean's mass. In the early universe, instabilities were large enough to produce galaxies and clusters of galaxies. Related category STELLAR ASTROPHYSICS• GRAVITATIONAL PHYSICS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History |