Astrophysics (index)about

Moon

(Earth's natural satellite)

A Moon is a natural satellite of a planet. (A Satellite is an object orbiting a planet, and can either be Natural, like the Moon, or Artificial, like HST.)

More specifically, the Earth's natural satellite is called the Moon. Tidal Locking keeps the same face to the Earth, and it rotates roughly perpendicular to the Ecliptic, so its poles have shadows that receive no light from the Sun. Places cold enough to keep water Ice frozen are called Lunar Cold Traps.

Current theory on the origin of the moon (Moon Formation) favors the Giant-Impact Hypothesis, that the moon coalesced from orbiting debris from an impact between Earth and a Mars-sized planet. Characteristics of lunar material show a striking similarity to that of Earth in Abundances and radioactivity, as compared to other planets such as Mars. This supports the giant impact hypothesis, yet it is too much like Earth, providing no evidence of different material from the presumed impacting planet.

The moon is thought to have a relatively small Iron core. The moon does not have the type of Magnetic Field that suggests a current Dynamo and it is thought the moon is solid (unlike Earth), but the Moon's magnetic rocks might reveal its early thermal history, before it cooled.

Other well-known Solar System moons:

Planet Well-known moons 6/2018 total
moon count
Mars Deimos, Phobos 2
Jupiter Io, Europa, Ganymede, Callisto (the Galilean Moons) 69
Saturn Titan, Mimas, Enceladus, Tethys, Dione, Rhea, Iapetus, Hyperion 62
Uranus Miranda, Ariel, Umbriel, Oberon, Titania 27
Neptune Triton 14
Pluto Charon 5

Moons of the planets are still being discovered. None are known for Mercury or Venus, but they have been found for more than 300 Minor Planets.


(moon,object,object type,Earth)
http://en.wikipedia.org/wiki/Moon
http://en.wikipedia.org/wiki/Natural_satellite

Referenced by:
Abundances
Accretion Rate
Aerosols
Albedo
Arecibo Occultation Survey (AO)
Apparent Magnitude (m)
Appulse
Astronomical Quantities
Atmosphere
Atmospheric Temperature Profile
Astronomical Unit (AU)
Barycenter
Basalt
Bathymetry
Callisto
Cassini
Chemical Equilibrium (CE)
Celestial Mechanics
Methane (CH4)
CIG
Circumplanetary Disk
Circular Polarization Ratio (CPR)
Crustal Magnetism
Crustal Plates
Cryovolcano
Carl Sagan Institute (CSI)
Double Transit
Dragonfly
Drogue Chute
Dwarf Planet
Dynamo
Earth
Earthshine
Eccentricity (e)
Enceladus
Enceladus Life Finder (ELF)
Ephemeris
Europa
Europa Clipper
Exosatellite
EXOSAT
47 Tucanae (47 Tuc)
Galileo
Ganymede
General Circulation Model (GCM)
Geochemistry
Gravity
Greenhouse Effect
Hadley Cell
Hill Radius
Hipparchus
Humidity
Hydrology
Hyperion
Impact
In Situ
Internal Gravity Wave
Io
Isolation Mass
Intertropical Convergence Zone (ITCZ)
JUICE
Jupiter
Kozai Mechanism
Lagrangian Point
LCROSS
Late Heavy Bombardment (LHB)
Libration
Love Number
Lunar Reconnaissance Orbiter (LRO)
Lunar Swirl
Lunar Water
Magnetic Anomaly
Magnetic Field
Magnetic Induction
Magnetometer
Mars
Mass Extinction
Mass Spectrometer
Mercury
Meridian
Minor Planet
MMX
Moon Formation
Solar Mass (MSun)
Nebula
Neptune
Neutron Scattering
Ammonia (NH3)
Obliquity
Occultation Observations
Orbital Inclination
Orbital Resonance
Orbital Speed
Polycyclic Aromatic Hydrocarbon (PAH)
Paleomagnetism
Particle Spectrometer
Phase Curve
Planetary Protection
Planet Formation
Planetoid
Pluto
Precession
Radar
Radioactive Dating
Radioactive Heating
Rayleigh Scattering
Reduced Mass
Regolith
Roche Limit
Saturn
Seismic Waves
SELENE
Shepherd Moon
Sidereal
Solar System
SPACEWATCH
SSSB
Standard Gravitational Parameter (μ)
Stellar Radius Determination
Superrotating Wind
Surface Brightness
Synodic Period
Tidal Force
Tidal Heating
Tidal Locking
Tide
Titan
TiNy Titans (TNT)
Transit
Transmission Spectroscopy
Triton
Uranus
USNO
Venus

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