gravitational instability

gravitational instability

The tendency for fluctuations in an inhomogeneous medium to grow because of self-gravitation. It is opposed by pressure forces. The critical length-scale beyond which such condensations collapse is known as a Jeans length, and the Jeans mass it encloses eventually forms a stable gravitationally bound system. The Jeans length is thus often taken as a characteristic length-scale for gravitational collapse; an interstellar cloud larger than the Jeans length will fragment into clumps with this characteristic size. See also galaxies, formation and evolution.

gravitational instability

[‚grav·ə′tā·shən·əl ‚in·stə′bil·əd·ē]
(mechanics)
Instability of a dynamic system in which gravity is the restoring force.
References in periodicals archive ?
Boss' new model demonstrates how a phase of marginal gravitational instability in the gas disk surrounding a proto-sun, leading to an outburst phase, can explain all of these findings.
In the gravitational instability model, some of the gas and dust suddenly clumps and collapses, simultaneously creating a planet's core and atmosphere.
There has been considerable uncertainty about how systems of planets form, with two leading models, called core accretion and gravitational instability.
Much theoretical effort has gone in to understanding the gravitational collapse of protostar but the question of gravitational instability of partially-ionized gaseous medium in the presence of radiative heat-loss function is of particular interest in cosmogony.
This theorem is applicable exactly to the case of the gravitational instability of the cosmic clouds.
Further, the gravitational instability of oceanic islands indicates that collapses could imperil major cities bordering the ocean basins (McGuire, 1996).
Dynamics of stellar disks (including the equilibrium of the axisymmetric disc, dynamics of perturbations in the disc plane, physics of gravitational instability, the conditions of gravitational stability of the disc, stability of stellar disks in relation to the bending perturbations);
There has been uncertainty about how planets in other solar systems formed, with two leading models, called core accretion and gravitational instability.
In contrast, Nayakshin begins with the giant blob of gas generated by gravitational instability.
Gravitational instability formed galaxies and their clusters whose high temperatures make them observable using X-rays.
It is thought that these short bursts of mass accretion are driven by marginal gravitational instability in the gas disk.
In the competing model, called gravitational instability, a planet forms wholesale when a cloud of gas, ice, and dust breaks into clumps.