Inferior and superior planets Inferior and superior planets In the Solar System, a planet is said to be inferior or interior with respect to another planet if its orbit lies inside the other planet's orbit around the Sun. In this situation, the latter planet is said to be superior to the former. In the reference frame of the Earth, in which the terms were originally used, the inferior planets are Mercury and Venus, while the superior planets are Mars, Jupiter, Saturn, Uranus and Neptune. Dwarf planets like Ceres or Pluto and most asteroids are 'superior' in the sense that they almost all orbit outside
Water on terrestrial planets of the Solar System primordial ×1.6 SMOW ratio suggests that ~ of has been lost to space via solar wind stripping. The cometary and asteroidal delivery of water to accreting Earth and Mars has significant caveats, even though it is favored by D/H isotopic ratios. Key issues include: An alternative to the cometary and asteroidal delivery of HO would be the accretion via physisorption during the formation of the terrestrial planets in the solar nebula. This would be consistent with the thermodynamic estimate of around two Earth masses of water vapor within 3AU of the solar accretionary disk, which would exceed by a factor