The Moon is a rounded astronomical body of planetary mass, rocky silicate composition and without significant atmosphere, hydrosphere or magnetic field. A full lunar day, the synodic period, takes two days longer as its orbit and has the same length as the completion of the lunar phases observed from Earth. The Moon is thought to have formed about 4. 51 billion years ago, not long after Earth. New research of Moon rocks, although not rejecting the Theia hypothesis, suggests that the Moon may be older than previously thought.
About Moon in brief
The Moon is a rounded astronomical body of planetary mass, rocky silicate composition and without significant atmosphere, hydrosphere or magnetic field. It is orbiting the planet Earth of the inner Solar System, as Earth’s only natural satellite. A full lunar day, the synodic period, takes two days longer as its orbit and has the same length as the completion of the lunar phases observed from Earth. The mean diameter of the Moon is 3474. 8 km, about one fourth of Earth’s and compareable to the width of Australia. The Moon is thought to have formed about 4. 51 billion years ago, not long after Earth. New research of Moon rocks, although not rejecting the Theia hypothesis, suggests that the Moon may be older than previously thought. Both the Moon’s natural prominence in the earthly sky and its regular cycle of phases as seen from Earth have provided cultural references and influences for human societies and cultures since time immemorial. The usual English proper name for Earth’s natural satellite is simply the Moon, with a capital M. The noun moon is derived from Old English mōna, which stems from Proto-Germanic *mēnōn, which may be related to verb mēnsis. The name Luna is used in scientific writing and especially science fiction to distinguish the Earth’s moon from others, while in poetry it has been used to denote Earth’s personification of the moon. The word lūnni, derived from the Latin Moon, is the word for the Greek goddess of the same name, Lunar, which in turn comes from the Proto-Indo-European *menensis, which is related to the word Luna, the name for the month of Luna, from the Greek word lulai, which means’moon’ or ‘lunar’ The Moon was first reached by a human-made object in September 1959, when the Soviet Union’s Luna 2, an uncrewed spacecraft, was intentionally crashed onto the lunar surface.
This accomplishment was followed by the first successful soft landing on the Moon by Luna 9 in 1966. The United States’ NASA Apollo program achieved the only human lunar missions to date, beginning with the first human orbital mission by Apollo 8 in 1968, and six human landings between 1969 and 1972. Since the 1972 Apollo 17 mission, the Moon has been visited only by un-crewed spacecraft. The moon is, after Jupiter’s satellite Io, the moon with the second highest surface gravity and density in the Solar System among those whose densities are known. With this size it is a planetary-sized moon and the fifth-largest satellite in theSolar System, it is larger than any dwarf planet, and by far the largest among planetary satellites relative to the size of the planet that it orbits. The most widely accepted explanation is that the moon formed from the debris left over after a giant impact between Earth and a hypothetical Mars-sized body called Theia.
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This page is based on the article Moon published in Wikipedia (as of Dec. 04, 2020) and was automatically summarized using artificial intelligence.
