Earth

Earth Astronomical symbol of Earth
The Earth seen from Apollo 17.jpg
The Blue Marble photograph of Earth, taken during the Apollo 17 lunar mission in 1972
Orbital characteristics
Epoch J2000 [n 1]
Aphelion 152100000 km [n 2]
(94500000 mi; 1.017 AU)
Perihelion 147095000 km [n 2]
(91401000 mi; 0.98327 AU)
149598023 km [1]
(92955902 mi; 1.00000102 AU)
Eccentricity 0.0167086 [1]
365.256363004 d [2]
(1.00001742096  yr)
29.78 km/s [3]
(107200 km/h; 66600 mph)
358.617°
Inclination
−11.26064° [3] to J2000 ecliptic
114.20783° [3]
Satellites
Physical characteristics
Mean radius
6371.0 km (3958.8 mi) [6]
Equatorial radius
6378.1 km (3963.2 mi) [7] [8]
Polar radius
6356.8 km (3949.9 mi) [9]
Flattening 0.0033528 [10]
1/298.257222101 ( ETRS89)
Circumference
  • 510072000 km2 (196940000 sq mi) [13] [14] [n 4]
  • 148940000 km2 land (57510000 sq mi; 29.2%)
  • 361132000 km2 water (139434000 sq mi; 70.8%)
Volume ×1012 km3 (2.59876×1011 cu mi) [3]
Mass 5.97237×1024 kg (1.31668×1025 lb) [15]
(3.0×10−6  M)
Mean density
5.514 g/cm3 (0.1992 lb/cu in) [3]
9.807 m/s2 ( 7000100000000000000♠1 g; 32.18 ft/s2) [16]
0.3307 [17]
11.186 km/s [3]
(40270 km/h; 25020 mph)
0.99726968 d [18]
(23h 56m 4.100s)
Equatorial rotation velocity
0.4651 km/s [19]
(1674.4 km/h; 1040.4 mph)
23.4392811° [2]
Albedo
Surface temp. min mean max
Kelvin 184 K [20] 288 K [21] 330 K [22]
Celsius −89.2 °C 15 °C 56.7 °C
Fahrenheit −128.5 °F 59 °F 134 °F
Atmosphere
Surface pressure
101.325  kPa (at MSL)
Composition by volume

Earth is the third planet from the Sun and the only object in the Universe known to harbor life. According to radiometric dating and other sources of evidence, Earth formed over 4 billion years ago. [24] [25] [26] Earth's gravity interacts with other objects in space, especially the Sun and the Moon, Earth's only natural satellite. Earth revolves around the Sun in 365.26 days, a period known as an Earth year. During this time, Earth rotates about its axis about 366.26 times. [n 5]

Earth's axis of rotation is tilted, producing seasonal variations on the planet's surface. [27] The gravitational interaction between the Earth and Moon causes ocean tides, stabilizes the Earth's orientation on its axis, and gradually slows its rotation. [28] Earth is the densest planet in the Solar System and the largest of the four terrestrial planets.

Earth's lithosphere is divided into several rigid tectonic plates that migrate across the surface over periods of many millions of years. About 71% of Earth's surface is covered with water, mostly by oceans. [29] The remaining 29% is land consisting of continents and islands that together have many lakes, rivers and other sources of water that contribute to the hydrosphere. The majority of Earth's polar regions are covered in ice, including the Antarctic ice sheet and the sea ice of the Arctic ice pack. Earth's interior remains active with a solid iron inner core, a liquid outer core that generates the Earth's magnetic field, and a convecting mantle that drives plate tectonics.

Within the first billion years of Earth's history, life appeared in the oceans and began to affect the Earth's atmosphere and surface, leading to the proliferation of aerobic and anaerobic organisms. Some geological evidence indicates that life may have arisen as much as 4.1 billion years ago. Since then, the combination of Earth's distance from the Sun, physical properties, and geological history have allowed life to evolve and thrive. [30] [31] In the history of the Earth, biodiversity has gone through long periods of expansion, occasionally punctuated by mass extinction events. Over 99% of all species [32] that ever lived on Earth are extinct. [33] [34] Estimates of the number of species on Earth today vary widely; [35] [36] [37] most species have not been described. [38] Over 7.4 billion humans live on Earth and depend on its biosphere and natural resources for their survival. Humans have developed diverse societies and cultures; politically, the world has about 200 sovereign states.

Name and etymology

The modern English word Earth developed from a wide variety of Middle English forms, [n 6] which derived from an Old English noun most often spelled eorðe. [39] It has cognates in every Germanic language, and their proto-Germanic root has been reconstructed as *erþō. In its earliest appearances, eorðe was already being used to translate the many senses of Latin terra and Greek γῆ (): the ground, [n 7] its soil, [n 8] dry land, [n 9] the human world, [n 10] the surface of the world (including the sea), [n 11] and the globe itself. [n 12] As with Terra and Gaia, Earth was a personified goddess in Germanic paganism: the Angles were listed by Tacitus as among the devotees of Nerthus, [48] and later Norse mythology included Jörð, a giantess often given as the mother of Thor. [49]

Originally, earth was written in lowercase, and from early Middle English, its definite sense as "the globe" was expressed as the earth. By early Modern English, many nouns were capitalized, and the earth became (and often remained) the Earth, particularly when referenced along with other heavenly bodies. More recently, the name is sometimes simply given as Earth, by analogy with the names of the other planets. [39] House styles now vary: Oxford spelling recognizes the lowercase form as the most common, with the capitalized form an acceptable variant. Another convention capitalizes "Earth" when appearing as a name (e.g. "Earth's atmosphere") but writes it in lowercase when preceded by the (e.g. "the atmosphere of the earth"). It almost always appears in lowercase in colloquial expressions such as "what on earth are you doing?" [50]

Other Languages
Acèh: Bumoë
адыгабзэ: ЧIыгу
Afrikaans: Aarde
Alemannisch: Erde
አማርኛ: መሬት
Ænglisc: Eorðe
Аҧсшәа: Адгьыл
العربية: الأرض
aragonés: Tierra
ܐܪܡܝܐ: ܐܪܥܐ
armãneashti: Locu
arpetan: Tèrra
অসমীয়া: পৃথিৱী
asturianu: Tierra
Avañe'ẽ: Yvy
Aymar aru: Aka pacha
azərbaycanca: Yer
تۆرکجه: یئر
বাংলা: পৃথিবী
Bahasa Banjar: Bumi
Bân-lâm-gú: Tē-kiû
Basa Banyumasan: Bumi
башҡортса: Ер
беларуская: Зямля (планета)
беларуская (тарашкевіца)‎: Зямля
भोजपुरी: पृथ्वी
Bikol Central: Kinaban
български: Земя
Boarisch: Eadn
བོད་ཡིག: སའི་གོ་ལ།
буряад: Дэлхэй
català: Terra
Чӑвашла: Çĕр (планета)
čeština: Země
Chavacano de Zamboanga: Tierra
chiShona: Rinopasi
Cymraeg: Y Ddaear
dansk: Jorden
Deutsch: Erde
ދިވެހިބަސް: ބިން
Diné bizaad: Nahasdzáán
dolnoserbski: Zemja
Ελληνικά: Γη
emiliàn e rumagnòl: Tèra
español: Tierra
Esperanto: Tero
estremeñu: Tierra
euskara: Lurra
فارسی: زمین
Fiji Hindi: Dunia
føroyskt: Jørðin
français: Terre
Frysk: Ierde
furlan: Tiere
Gaeilge: An Domhan
Gaelg: Yn Dowan
galego: Terra
贛語: 地球
Gĩkũyũ: Thĩ
ગુજરાતી: પૃથ્વી
𐌲𐌿𐍄𐌹𐍃𐌺: 𐌰𐌹𐍂𐌸𐌰
गोंयची कोंकणी / Gõychi Konknni: धर्तरी
客家語/Hak-kâ-ngî: Thi-khiù
хальмг: Делкә һариг
한국어: 지구
Hausa: Duniya
Hawaiʻi: Honua
Հայերեն: Երկիր
हिन्दी: पृथ्वी
hornjoserbsce: Zemja
hrvatski: Zemlja
Ido: Tero
Igbo: Àlà
Bahasa Indonesia: Bumi
interlingua: Terra
Interlingue: Terra
ᐃᓄᒃᑎᑐᑦ/inuktitut: ᓄᓇ
Ирон: Зæхх
isiZulu: Umhlaba
íslenska: Jörðin
italiano: Terra
עברית: כדור הארץ
Basa Jawa: Bumi
kalaallisut: Nunarsuaq
ಕನ್ನಡ: ಭೂಮಿ
Kapampangan: Yatu
къарачай-малкъар: Джер
ქართული: დედამიწა
kaszëbsczi: Zemia
қазақша: Жер
kernowek: Dor
Kinyarwanda: Isi
Kiswahili: Dunia
коми: Му
Kongo: Ntoto
Kreyòl ayisyen: Latè
Kurdî: Erd
Кыргызча: Жер
кырык мары: Мӱлӓндӹ (планета)
Ladino: Tierra
ລາວ: ໂລກ
لۊری شومالی: جأهوٙن
latgaļu: Zeme
latviešu: Zeme
Lëtzebuergesch: Äerd
lietuvių: Žemė
Ligure: Tæra
Limburgs: Eerd
lingála: Mabelé
la .lojban.: terdi
lumbaart: Tera
magyar: Föld
मैथिली: पृथ्वी
македонски: Земја (планета)
Malagasy: Tany
മലയാളം: ഭൂമി
Malti: Art
मराठी: पृथ्वी
მარგალური: დიხაუჩა
مصرى: الارض
مازِرونی: زمین
Bahasa Melayu: Bumi
Baso Minangkabau: Bumi
Mìng-dĕ̤ng-ngṳ̄: Dê-giù
Mirandés: Tierra
монгол: Дэлхий
မြန်မာဘာသာ: ကမ္ဘာဂြိုဟ်
Nāhuatl: Tlalticpactli
Dorerin Naoero: Eb
Nederlands: Aarde (planeet)
Nedersaksies: Eerde
नेपाली: पृथ्वी
नेपाल भाषा: प्रिथिबी
日本語: 地球
Napulitano: Terra
нохчийн: Дуьне
Nordfriisk: Jard
Norfuk / Pitkern: Erth
norsk: Jorden
norsk nynorsk: Jorda
Nouormand: Tèrre
Novial: Tere
occitan: Tèrra
олык марий: Мланде (планет)
ଓଡ଼ିଆ: ପୃଥିବୀ
oʻzbekcha/ўзбекча: Yer
ਪੰਜਾਬੀ: ਧਰਤੀ
Pälzisch: Erd
پنجابی: زمین
Papiamentu: Tera
پښتو: ځمکه
Patois: Oert
Перем Коми: Мушар
ភាសាខ្មែរ: ផែនដី
Picard: Tière
Piemontèis: Tèra (pianeta)
Tok Pisin: Giraun
Plattdüütsch: Eer
polski: Ziemia
português: Terra
Qaraqalpaqsha: Jer
qırımtatarca: Dünya
Ripoarisch: Ääd (Planeet)
română: Pământ
Romani: Phuv
rumantsch: Terra
Runa Simi: Tiksimuyu
русиньскый: Земля (планета)
русский: Земля
саха тыла: Сир
davvisámegiella: Eana
संस्कृतम्: पृथ्वी
sardu: Terra
Scots: Yird
Seeltersk: Äide
Sesotho: Lefatshe
Sesotho sa Leboa: Lefase
shqip: Toka
sicilianu: Terra (pianeta)
සිංහල: මහ පොළොව
Simple English: Earth
سنڌي: زمين
slovenčina: Zem
slovenščina: Zemlja
словѣньскъ / ⰔⰎⰑⰂⰡⰐⰠⰔⰍⰟ: Ꙁємлꙗ
ślůnski: Źymja
Soomaaliga: Dhul
کوردی: زەوی
српски / srpski: Земља
srpskohrvatski / српскохрватски: Zemlja
Basa Sunda: Marcapada
suomi: Maa
svenska: Jorden
Tagalog: Daigdig
தமிழ்: புவி
Taqbaylit: Akal
татарча/tatarça: Җир
తెలుగు: భూమి
tetun: Rai
тоҷикӣ: Замин
ᏣᎳᎩ: ᎡᎶᎯ
ತುಳು: ಭೂಮಿ
Türkçe: Dünya
Türkmençe: Ýer
тыва дыл: Чер
удмурт: Музъем
українська: Земля
اردو: زمین
ئۇيغۇرچە / Uyghurche: يەر شارى
Vahcuengh: Giuznamh
vèneto: Tera
vepsän kel’: Ma
Tiếng Việt: Trái Đất
Volapük: Tal
walon: Daegne
文言: 坤輿
West-Vlams: Eirde (planete)
Winaray: Kalibotan
Wolof: Suuf
吴语: 地球
Xitsonga: Misava
ייִדיש: ערד-פלאנעט
Yorùbá: Ayé
粵語: 地球
Zazaki: Dınya
Zeêuws: Aerde
žemaitėška: Žemė
中文: 地球
डोटेली: पृथ्वी
Kabɩyɛ: Tɛtʋ