The Gods of Mars the two Viking missions which found a dead, frozen world where water does not exist in a fluid state. The Valley of Dor, with the ring of cliffs around it and Sea of Korus within it, is placed in a mile-deep crater at Mars' South Pole. However, Burroughs makes a mistake in that he has the sun rise in the east and set in the west as elsewhere in the planet, and the moons are visible from the Valley. In reality, at the South Pole, Mars' moons would not be seen, and the sun would not rise in the east
Planet hydrostatic equilibrium (to be rounded under its own gravity), but not enough to sustain core fusion like a star. By definition, all planets are "planetary-mass objects", but the purpose of this term is to refer to objects that do not conform to typical expectations for a planet. These include dwarf planets, which are rounded by their own gravity but not massive enough to clear their own orbit, the larger moons, and free-floating planemos, which may have been ejected from a system (rogue planets) or formed through cloud-collapse rather than accretion (sometimes called sub-brown dwarfs). A dwarf planet is a planetary-mass