Pronunciation /ˈluːnə/
Adjective Lunar, Selenic, Selenitive
Physical characteristics
Mean radius 1,737.10 km
(0.273 Earths)
Equatorial surface gravity 3.24400 m/s2
(0.330 8 g)
Axial tilt 1.5424° (to ecliptic)

Luna is Earth's only natural satellite and the fifth-largest satellite in the Solar System. It is one-quarter of Earth's diameter and 1⁄81 its mass. It has similar features to Earth itself, such as water, land, animals and even intelligent life forms, the lunans. Luna is sometimes referred to as the Moon, the Green Planet and Selenica.


"Luna" in different languages

Language Name Transliteration
Belarusian Месяц Miesiac
Croatian Mjesec
Classical Chinese
Chinese 卢纳 or 月亮 Luna or The Moon
English Luna or The Moon
French La lune
German Der Mond
Greek Η Σελήνη I Selíni
Greenlandic Qaammat
Georgian მთვარე mt’vare
Hungarian Hold
Hindi चन्द्रमा Candramā
Icelandic Tunglið
Indonesian Bulan
Inuktitut ᑕᖅᑭᖅ Taqqiq
Italian La Luna
Japanese ムーン Mun
Danish, Norwegian, Swedish Månen
Finnish, Estonian Kuu
Kannada చంద్రుడు Candruḍu
Korean Dal
Latin Lunae
Lativan Mēness
Lithuanian Mėnulis
Macedonian Месечината Mesečinata
Mongolian Сар
Portuguese Lua
Russian, Bulgarian Луна Luna
Romanian Lună
Serbian Месец Mesec
Slovak Mesiac
Spanish La Luna
Tatar Ай
Tamil நிலா Nilā
Thai ดวงจันทร์ Dwng cạnthr̒
Turkish Ay'ın
Talnuwathiki Talnuwathi
Ukrainian Місяць Misyatsʹ
Vietnamese Mặt trăng
Welsh Lleuad


A planet that can sustain life is known as habitable, even if life did not originate there. Luna, along with Earth, are the only two known celestial bodies that provide the (currently understood) conditions of liquid water, an environment where complex organic molecules can assemble, and sufficient energy to sustain metabolism. The distance of Luna from the Sun, as well as its orbital eccentricity, rate of rotation, axial tilt, geological history, sustaining atmosphere and protective magnetic field all contribute to the conditions believed necessary to originate and sustain life on this planet.


Natural resources and land use

Luna is a Pangaea-like moon, comprised of one major continent with smaller islands surrounding it. Most of Luna is comprised of land, (unlike Earth which is mostly comprised of water) which is why many humans consider Luna "the Green Planet."


Near side of Luna

Far side of Luna

  • The beginning of the Merkili Rain forest range.
  • Picture of Luna taken from Earth at night.
  • Aitken Basin during "winter."
  • Aurora borealis with Luna in the background.
  • Coast of the Aitken Basin.
  • Middle of the Aitken Basin.
  • The edge of the Aitken Basin, a few days before "winter."
  • A large crater.
  • Aitken Basin during "summer."

The Aitken Basin during the warm 14 Lunar days when the far side of Luna faces the sun.


Details of the Earth-Lunar system. (Photos and data from NASA.)


A scale representation of the relative sizes of, and average distance between, Earth and Luna (click to enlarge).