Definition of planet object can be irregular in shape, but beyond that point gravity begins to pull an object towards its own centre of mass until the object collapses into an ellipsoid. (None of the large objects of the Solar System are truly spherical. Many are spheroids, and several, such as the larger moons of Jupiter and Saturn and the dwarf planet , have been further distorted into ellipsoids by rapid rotation or tidal forces, but still in hydrostatic equilibrium.) However, there is no precise point at which an object can be said to have reached hydrostatic equilibrium. As Soter noted in his
Mongo (fictional planet) peoples of Mongo have evolved into different forms, such as the winged Hawkmen, the tailed Lion Men, and the underwater dwelling Coralians. Mongo is about half the diameter of Earth but is considerably denser, so its gravity is only slightly weaker than the Earth's, though it still allows Flash Gordon to put his gymnastics skills to good use. Mongo has a variety of climates, and is inhabited by enormous, dinosaur-like monsters. In Alex Raymond's comic strip and the Flash Gordon movie serials, Mongo was shown as a rogue planet that had drifted into Earth's solar system. Later versions of the