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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.
"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.
Seen from a superior planet, an inferior planet on the opposite side of the Sun is in superior conjunction with the Sun. An inferior conjunction occurs when the two planets align on the same side of the Sun. At inferior conjunction, the superior planet is "in opposition" to the Sun as seen from the inferior planet (see the diagram).
With the development of space travel, as well as in hypothetical observations from other points in space, the notion of phase angle became independent of Sun and Earth. The etymology of the term is related to the notion of planetary phases, since the brightness of an object and its appearance as a "phase" is the function of the phase angle.
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 ...
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 ...
Earth's atmosphere contains 78% nitrogen and 21% oxygen, which is the result of the presence of life. [103] [104] The planet has a complex climate and weather system, with conditions differing drastically between climate regions. [105] The solid surface of Earth is dominated by green vegetation, deserts and white ice sheets.
Earth science or geoscience includes all fields of natural science related to the planet Earth. [1] This is a branch of science dealing with the physical, chemical, and biological complex constitutions and synergistic linkages of Earth's four spheres: the biosphere , hydrosphere / cryosphere , atmosphere , and geosphere (or lithosphere ).