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The superior planets, orbiting outside the Earth's orbit, do not exhibit a full range of phases since their maximum phase angles are smaller than 90°. Mars often appears significantly gibbous, it has a maximum phase angle of 45°. Jupiter has a maximum phase angle of 11.1° and Saturn of 6°, [1] so their phases are almost always full.
The current Venusian atmosphere has only ~200 mg/kg H 2 O(g) in its atmosphere and the pressure and temperature regime makes water unstable on its surface. Nevertheless, assuming that early Venus's H 2 O had a ratio between deuterium (heavy hydrogen, 2H) and hydrogen (1H) similar to Earth's Vienna Standard Mean Ocean Water of 1.6×10 −4, [7] the current D/H ratio in the Venusian atmosphere ...
Planets whose orbits lie within the orbit of Earth. [nb 1] Mercury and Venus: Inner planet: A planet in the Solar System that have orbits smaller than the asteroid belt. [nb 2] Mercury, Venus, Earth, Mars: Outer planet: A planet in the Solar System beyond the asteroid belt, and hence refers to the gas giants. Jupiter, Saturn, Uranus and Neptune ...
"Inferior planet" refers to Mercury and Venus, which are closer to the Sun than Earth is. "Superior planet" refers to Mars, Jupiter, Saturn, Uranus, and Neptune (the latter two added later), which are further from the Sun than Earth is. The terms are sometimes used more generally; for example, Earth is an inferior planet relative to Mars.
Earth is the only terrestrial planet known to have an active hydrosphere. Terrestrial planets are substantially different from the giant planets, which might not have solid surfaces and are composed mostly of some combination of hydrogen, helium, and water existing in various physical states.
For some objects, such as the Moon (see lunar phases), Venus and Mercury the phase angle (as seen from the Earth) covers the full 0–180° range. The superior planets cover shorter ranges. For example, for Mars the maximum phase angle is about 45°. For Jupiter, the maximum is 11.1° and for Saturn 6°. [1]
The Earth phase, Terra phase, terrestrial phase, or phase of Earth, is the shape of the directly sunlit portion of Earth as viewed from the Moon (or elsewhere extraterrestrially). From the Moon, the Earth phases gradually and cyclically change over the period of a synodic month (about 29.53 days), as the orbital positions of the Moon around ...
The apparent brightness of Mercury as seen from Earth is greatest at phase angle 0° (superior conjunction with the Sun) when it can reach magnitude −2.6. [14] At phase angles approaching 180° (inferior conjunction) the planet fades to about magnitude +5 [14] with the exact brightness depending on the phase angle at that particular ...