Earth Moon

A Earth Moon is a planetary moon that orbits around the Earth and constitutes the Earth's only natural satellite.

• AKA: The Moon, Luna, Lunar Body.
• Context:
  • It can typically contain Earth moon geological compositions including an outer Earth moon anorthositic crust, an Earth moon mantle rich in Earth moon silicate minerals, and a partially molten Earth moon metallic core.
  • It can typically orbit The Earth at an Earth lunar distance (from approximately 16,000 kilometers shortly after formation to current ~384,400 kilometers).
  • It can typically complete Earth moon orbital cycles (from approximately 5-7 Earth days in its early history to current ~27.3 Earth days sidereal period).
  • It can typically maintain tidal lock with the Earth, presenting the same Earth moon face continuously to Earth observers.
  • It can typically influence Earth tidal systems through its Earth moon gravitational pull.
  • It can typically reflect solar light to create Earth night illumination.
  • It can typically undergo Earth moon phases depending on its Earth moon orbital position.
  • ...
  • It can range from being a Full Earth Moon to being a New Earth Moon, depending on its Earth moon illumination state.
  • It can range from being a Perigee Earth Moon to being an Apogee Earth Moon, depending on its Earth moon orbital distance.
  • ...
  • It can serve as an Earth moon exploration target for human space missions.
  • It can influence Earth cultures through Earth moon mythology and Earth moon symbolism.
  • It can affect Earth biological rhythms through its Earth moon phase cycle.
  • It can provide scientific research opportunities for Earth moon composition studies.
  • It can have Earth Moon Surface with diverse Earth moon geological features and Earth moon terrain.
  • It can have Earth Moon Mass of approximately 7.342 × 10^22 kg, about 1/81 of Earth mass.
  • It can have Earth Moon Diameter of approximately 3,474 km, about 1/4 of Earth diameter.
  • It can have Earth Moon Gravity of approximately 1.62 m/s², about 1/6 of Earth gravity.
  • It can have Earth Moon Core consisting of Earth moon solid inner core and possible Earth moon liquid outer core.
  • It can influence Earth rotation through Earth-Moon tidal interaction.
  • It can stabilize Earth axial tilt which helps maintain Earth climate stability.
  • ...
• Examples:
  • Earth Moon Evolutionary Periods, such as:
    • Formative Earth Moon (4.51 billion years ago), characterized by Earth moon coalescence following the Theia impact event.
    • Magma Ocean Earth Moon (4.5-4.3 billion years ago), when the Earth moon surface was covered in Earth moon molten rock.
    • Late Heavy Bombardment Earth Moon (4.1-3.8 billion years ago), experiencing intense Earth moon crater formation.
    • Mare Formation Earth Moon (3.9-3.2 billion years ago), when Earth moon volcanic activity created the dark Earth moon maria.
    • Declining Activity Earth Moon (3.2-1.0 billion years ago), with gradually reduced Earth moon volcanic processes.
    • Quiescent Earth Moon (1 billion years ago to present), characterized by minimal Earth moon geological activity.
  • Earth Moon Regions, such as:
    • Earth Moon Maria (dark plains), such as:
      • Mare Tranquillitatis (Sea of Tranquility), site of the first human Earth moon landing.
      • Mare Imbrium (Sea of Rains), demonstrating ancient Earth moon volcanic activity.
      • Mare Serenitatis (Sea of Serenity), showcasing extensive Earth moon basaltic plains.
    • Earth Moon Highlands (light areas), such as:
      • Terra Crisium surrounding Mare Crisium, showing Earth moon crustal formation.
      • Lunar Alps demonstrating Earth moon mountain formation.
    • Earth Moon Craters, such as:
      • Tycho Crater with its distinctive Earth moon ray system.
      • Copernicus Crater showing Earth moon impact formation.
  • Earth Moon Explorations, such as:
    • Earth Moon Robotic Missions, such as:
      • Luna 2 (1959), first artificial Earth moon impact.
      • Luna 9 (1966), first soft Earth moon landing.
      • Lunar Reconnaissance Orbiter (2009-present), providing detailed Earth moon mapping.
    • Earth Moon Human Missions, such as:
      • Apollo 11 (1969), first human Earth moon landing and Earth moon sample return.
      • Apollo 17 (1972), final Apollo Earth moon mission with extensive scientific Earth moon exploration.
  • Earth Moon Temporal States, such as:
    • Earth Moon Phases, such as:
      • New Earth Moon when the Earth moon illuminated side faces away from Earth observers.
      • Full Earth Moon when the Earth moon illuminated side faces directly toward Earth observers.
    • Earth Moon Positions, such as:
      • Super Earth Moon when at Earth moon perigee during full Earth moon phase.
      • Micro Earth Moon when at Earth moon apogee during full Earth moon phase.
  • ...
• Counter-Examples:
  • Mars Moons, which orbit Mars rather than the Earth.
  • Artificial Earth Satellites, which are human-made orbital objects rather than natural celestial bodies.
  • Earth Trojan Asteroids, which follow the Earth's orbit around the Sun rather than orbiting the Earth directly.
  • Near-Earth Objects, which have solar orbits that bring them near the Earth but do not orbit the Earth.
• See: Exploration of The Moon, Near Side of The Moon, Lunar North Pole, Light-Second, Astronomical Unit, Earth Orbital System, Gravitational Field, Physical Location, Terrestrial Planet.

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References

2023

• (Wikipedia, 2023) ⇒ https://en.wikipedia.org/wiki/Moon Retrieved:2023-9-20.
  • The Moon is Earth's only natural satellite. It orbits around Earth at an average distance of , or about 30 times Earth's diameter, having a sidereal period of 27.3 days and a synodic period of 29.5 days. The Moon faces Earth always with its near side by having a rotation period that equals its orbital period, resulting from being tidally locked to Earth. Its gravitational influence is the main driver of Earth's tides and causes Earth's day to lengthen very slowly. Its diameter is , which is roughly one-quarter that of Earth or twice the width of Australia, making it by far the largest and most massive satellite in the Solar System in relation to its parent planet and the fifth-largest Solar System satellite overall. The Moon is a satellite planet in geophysical terms and among all planetary-mass objects of the Solar System larger and more massive than all known solar dwarf planets. The Moon's mass, density and surface gravity of about one-sixth of Earth's (at ), are rivaled among Solar System satellites only by Jupiter's moon Io. The body of the Moon is differentiated and terrestrial, with no significant atmosphere, hydrosphere, or magnetic field.

    The most widely accepted origin explanation posits that the Moon formed 4.51 billion years ago, not long after Earth's formation, out of the debris from a giant impact between Earth and a hypothesized Mars-sized body called Theia. It receded to a wider orbit because of tidal interaction with the Earth. The near side of the Moon is marked by dark volcanic maria ("seas"), which fill the spaces between bright ancient crustal highlands and prominent impact craters. Most of the large impact basins and mare surfaces were in place by the end of the Imbrian period, some three billion years ago.

    The Moon is the brightest celestial object in Earth's night sky. This is mainly due to its large angular diameter, while the reflectance of the lunar surface is comparable to that of asphalt. The apparent size is nearly the same as that of the Sun, allowing it to cover the Sun almost completely during a total solar eclipse. The Moon is, beside when passing through Earth's shadow during a lunar eclipse, always illuminated by the Sun, but from Earth the visible illumination shifts in the course of its orbit, producing the lunar phases. From Earth about 59% of the lunar surface is visible over time due to cyclical shifts in perspective (libration), making parts of the far side of the Moon visible.

    For Earth and life on it the Moon has been beside the Sun the most influential celestial object.

    Throughout human history the Moon's prominance in Earth's night sky and its consistent cycle of phases have offered a rich source of inspiration and knowledge, for areas from mythology, cosmography, religion, art, and language, to calendar systems, natural science and spaceflight. The first time an artificial object reached the Moon, was September 14, 1959, when the Soviet Union's Luna 2 performed an impact, while the first soft-landing was achieved in 1966 by Luna 9. In 1969 humans for the first time arrived on the Moon, landing on July 16 at Mare Tranquillitatis with the lander Eagle of Apollo 11 as part of the United States' Apollo program. Until 1972 five more crews were sent, with each time two men staying for up to twelve days. These missions remain the only times humans have visited an extraterrestrial body. Continued exploration of the Moon has allowed a detailed understanding of the Moon and its significance for Earth and life on it.

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