If an object is in hydrostatic equilibrium, a global layer of liquid on its surface would form a surface of the same shape as the body, apart from small-scale surface features such as craters and fissures. The body will have a spherical shape if it does not rotate and an ellipsoidal one if it does. The faster it rotates, the more oblate or even scalene it becomes. If such a rotating body were heated until it melts, its shape would not change. The extreme example of a body that may be scalene due to rapid rotation is Haumea, which is twice as long on its major axis as it is at the poles. If the body has a massive nearby companion, then tidal forces gradually slow its rotation until it is tidally locked; that is, it always presents the same face to its companion. Tidally locked bodies are also scalene, though sometimes only slightly so. Earth's Moon is tidally locked, as are all the rounded satellites of the gas giants. Pluto and Charon are tidally locked to each other, as are Eris and Dysnomia, and probably also Orcus and Vanth.