The Inner Cloud is also called the Hill Cloud and may be the maker of comets . The inner Oort cloud is also known as the Hills cloud , named after J. G. Hills , who proposed its existence in 1981 . Models predict that the inner cloud should have tens or hundreds of times as many cometary nuclei as the outer halo ; it is seen as a possible source of new comets to resupply the relatively tenuous outer cloud as the latter 's numbers are gradually depleted .