According to the Mormon scriptures (Doctrine and Covenants, Abraham 3) our galaxy, if not all galaxies, is posited to contain countless planets either already, or soon to be, inhabited by human-type life. The greatest of these planets is Kolob.
Kolob is said to be the greatest of the planets because it is "nearest unto the throne of God." But, it is also "the greatest of all the Kokau-beam that thou hast seen" ... "which signifies stars or all the great lights which were in the firmament of heaven." Moreover, at least two stars and possibly fifteen or more stars and planets, the Moon, the Earth, and the Sun receive their light from Kolob. Kolob also is said to be surrounded by many great stars which are near unto it (Abraham 3:2). According to this same passage (Abraham 3) the greater the planet the longer its rotational period. Kolob, the greatest, has a day equal to 1000 years.