This established the size of the accretion disc surrounding the accreting neutron stars. This gravitational accretion led to the formation of the planets. Galaxies grow through mergers and smooth gas accretion. As further accretion occurred, galaxies formed. Water masers are useful to observe nuclear accretion disks in active galaxies. He concluded that these moons formed from equatorial accretion disks. The peninsula was gradually expanded westward by the natural accretion of sand from tidal action. I (thermonuclear flashes) and type II (accretion flow instabilities). The increased growth rates fully depend on the accretion activity. Evidence of the accretion and dispersion of supercontinents is seen in the geological rock record. The study of oscillation modes in accretion disks is referred to as diskoseismology. The physics of accretion disks encounters some problems. The standard picture is of a torus of obscuring material surrounding the accretion disc. Growth later slows and continues as oligarchic accretion. This is a major component of the theory of accretion disks.