document_title: List of tidal power stations

question_text: where is tidal energy used most in the world

text: List of tidal power stations

text: Tidal power stations[edit]

text: Operational[edit]

text: The following table lists tidal power stations that are in operation as of August 2011.

text:
Station
Capacity (MW)
Country
Location
Comm
Ref

Annapolis Royal Generating Station
20
 Canada
44°45′07″N 65°30′40″W / 44.75194°N 65.51111°W / 44.75194; -65.51111 (Annapolis Royal Generating Station)
1984
[1]

Jiangxia Tidal Power Station
3.2
 China
28°20′34″N 121°14′25″E / 28.34278°N 121.24028°E / 28.34278; 121.24028 (Jiangxia Tidal Power Station)
1980
[2][3]

Kislaya Guba Tidal Power Station
1.7
 Russia
69°22′37″N 33°04′33″E / 69.37694°N 33.07583°E / 69.37694; 33.07583 (Kislaya Guba Tidal Power Station)
1968

Rance Tidal Power Station
240
 France
48°37′05″N 02°01′24″W / 48.61806°N 2.02333°W / 48.61806; -2.02333 (Rance Tidal Power Station)
1966

Sihwa Lake Tidal Power Station
254
 South Korea
37°18′47″N 126°36′46″E / 37.31306°N 126.61278°E / 37.31306; 126.61278 (Sihwa Lake Tidal Power Station)
2011
[4][5]

Strangford Lough SeaGen (Decommissioned in 2016)
1.2
 United Kingdom
54°22′04″N 05°32′40″W / 54.36778°N 5.54444°W / 54.36778; -5.54444 (Strangford Lough Seagen)
2008

Uldolmok Tidal Power Station
1.5
 South Korea
34°32′07″N 126°14′06″E / 34.53528°N 126.23500°E / 34.53528; 126.23500 (Uldolmok Tidal Power Station)
2009
[6]

Eastern Scheldt Barrier Tidal Power Plant
1.25
 The Netherlands
51°36′19″N 03°40′59″E / 51.60528°N 3.68306°E / 51.60528; 3.68306 (Eastern Scheldt Barrier Tidal Power Plant)
2015
[7]

text: Under construction[edit]

text: The following table lists tidal power stations that are currently under construction as of the date in each cited source.

text:
Station
Capacity (MW)
Country
Location
Start
Ref

Bluemull Sound
Tidal Stream Array
0.5
 United Kingdom
60°41′01″N 00°59′12″W / 60.68361°N 0.98667°W / 60.68361; -0.98667 (Bluemull Sound)
2016
[8]

Meygen Tidal Project
398
 United Kingdom
58°39′26.1504″N 3°7′1.5456″W / 58.657264000°N 3.117096000°W / 58.657264000; -3.117096000 (pentland firth)
2015
[9]

text: Proposed[edit]

text: There are many stations in proposal at the moment. The following table lists tidal power stations that are only at a proposal stage.

text:
Station
Capacity (MW)
Country
Location
Const
Ref

Garorim Bay Tidal Power Station
520
 South Korea
Garorim Bay

[4]

Incheon Tidal Power Station
818 or 1,320
 South Korea
37°29′48″N 126°20′32″E / 37.49667°N 126.34222°E / 37.49667; 126.34222 (Incheon Tidal Power Station)
2017
[4][10]

Severn Barrage
8,640
 United Kingdom
51°21′30″N 03°06′00″W / 51.35833°N 3.10000°W / 51.35833; -3.10000 (Severn Barrage_dim:8000)

Tugurskaya Tidal Power Plant
3,640
 Russia
Okhotsk Sea

[11]

Mezenskaya Tidal Power Plant
24,000
 Russia
Mezen Bay

[12]

Penzhinskaya Tidal Power Plant
87,100
 Russia
Penzhin Bay

Skerries Tidal Stream Array
10.5
 United Kingdom
53°26′N 04°36′W / 53.433°N 4.600°W / 53.433; -4.600 (Skerries Tidal Farm) approx.

[13]

Tidal Lagoon Swansea Bay
320
 United Kingdom
Swansea Bay
2015–2017
[14]

Gulf of Kutch Project
50
 India
Gulf of Kutch
2012
[15]

Alderney tidal plant
300
 Alderney
49°42′52″N 2°12′19″W / 49.71444°N 2.20528°W / 49.71444; -2.20528 (Alderney)
2020
[16]


document_title: 2018 Commonwealth Games

question_text: who are the host broadcasters of the commonwealth games

root

text: 2018 Commonwealth Games

text: Host selection[edit]

text: On 22 August 2008, the Premier of Queensland, Anna Bligh, officially launched Gold Coast City's bid to host the Commonwealth Games in 2018. On 7 April 2009, the ABC reported a land exchange deal between Gold Coast City and State of Queensland for Carrara Stadium. According to Mayor Ron Clarke, the land would aid a potential bid for the 2018 Commonwealth Games. The land exchanged would be used as the site of an aquatics centre. In the same article, Mayor Clarke raised the question of the Australian Federal Government's commitment to a 2018 Commonwealth Games bid in light of the Government's support for Australia's 2018 FIFA World Cup Finals bid.[9] On 16 April 2009, Queensland Premier Anna Bligh told reporters that a successful Commonwealth Games bid by Gold Coast City could help the tourist strip win a role in hosting the World Cup.[10]

tag: p

text: "Some of the infrastructure that would be built for the Commonwealth Games will be useful for Gold Coast City to get a World Cup game out of the soccer World Cup if we're successful as a nation," she said. However the decision on the venues for the 2018 and 2022 FIFA World Cups were made eleven months prior to the bid decision for the 2018 Commonwealth Games, so the potential World Cup venues had already been chosen. On 3 June 2009, Gold Coast City was confirmed as Australia's exclusive bidder vying for the 2018 Commonwealth Games.[11] "Should a bid proceed, Gold Coast City will have the exclusive Australian rights to bid as host city for 2018," Bligh stated.

text: "Recently I met with the president and CEO of the Australian Commonwealth Games Association and we agreed to commission a full and comprehensive feasibility study into the potential for the 2018 Commonwealth Games," she said. "Under the stewardship of Queensland Events new chair, Geoff Dixon, that study is now well advanced." On 15 March 2010, it was announced that the Queensland Government will provide initial funding of A$11 million for the 2018 Commonwealth Games bid. The Premier of Queensland has indicated the Government's support for the bid to the Australian Commonwealth Games Association.[12] On 31 March 2010, the Australian Commonwealth Games Association officially launched the bid to host the 2018 Commonwealth Games.[13] In October 2011, Gold Coast City Mayor Ron Clarke stated that the games would provide a strong legacy for the city after the games have ended.[14]

text: On 31 March 2010, a surprise bid was made for the 2018 Commonwealth Games by the Sri Lankan city of Hambantota. Hambantota was devastated by the 2004 Indian Ocean Tsunami, and is undergoing a major face lift. The first phase of the Port of Hambantota is nearing completion and it is funded by the government of China. The Mattala International Airport, which is the second international Airport of Sri Lanka is built close to Hambantota. A new Hambantota International Cricket Stadium had also been built, which had hosted matches in the 2011 Cricket World Cup.

text: On 10 November 2011, the Hambantota bidders claimed they had already secured enough votes to win the hosting rights.[15] However, on 11 November it was officially announced Gold Coast City had won the rights to host the games.[16][17]

text:
2018 Commonwealth Games bidding results

City
Country
Votes

Gold Coast City
 Australia
43

Hambantota
 Sri Lanka
27

tag: table

text: Administration[edit]

text: The event was overseen by the Gold Coast 2018 Commonwealth Games Corporation (GOLDOC). The GOLDOC was formed in 2012 by the Government of Queensland.[18] Its headquarters were located in Ashmore, a suburban region of Gold Coast.[19] In February 2012, Mark Peters was appointed Chief Executive Officer of the GOLDOC.[20] The Queensland Government Minister tasked with overseeing the Games was Kate Jones.[21]

text: Preparation[edit]

text: Venues[edit]

text: One of the key technical aspects of Gold Coast City's successful bid was the fact that the city had 80 percent of the planned venues in place before the bidding deadline. The vast majority of venues were located within 20-minutes driving time of the Athletes Village in Parkwood.

text: Venues in Gold Coast[edit]

text: Carrara Stadium, located in the suburb of Carrara, was the main venue for Athletics, the opening ceremony and the closing ceremony. The seating capacity of the stadium was temporarily increased to 40,000 for the games by the installation of a large temporary North Stand.[22]

text: The Gold Coast City Convention and Exhibition Centre, located in the suburb of Broadbeach, hosted Basketball, Netball (preliminaries) and Weightlifting events, also serving as the Main Media Centre and International Broadcast centre hosting over 3000 members of the worlds press.[23] The Broadbeach Bowls Club hosted the Bowls competition.[24]

text: The Hinze Dam, located in the suburb of Advancetown, was the location for the Mountain Bike competition. A new course was constructed to meet international competition requirements and temporary spectator seating for 2,000 spectators.

text: The newly built Coomera Sport and Leisure Centre hosted Gymnastics and Netball (finals).[25] The existing sound stages of the Village Roadshow Studios complex in the suburb of Oxenford hosted the sports of Boxing, Table Tennis and Squash.[26] During Games mode the venue was enhanced to provide for the International Sporting Federation technical venue requirements and provide spectator seating of 3,000 (boxing) and 3,200 (table tennis). The Gold Coast Hockey Centre hosted the men's and women's Hockey events during the games.[27] The Southport Broadwater Parklands hosted Triathlon and athletic events.[28] The Optus aquatic centre hosted the swimming and diving events.[29]

text: Robina Stadium hosted the Rugby 7s competition and upgraded to meet World Rugby standards.[30] The Elanora/Currumbin Valley area hosted the road racing elements of the cycling programme. Coolangatta Beachfront hosted the beach volleyball event.[31]

text: Venues outside Gold Coast[edit]

text: Brisbane, along with the Gold Coast, forms part of the South East Queensland conurbation. Track Cycling was held at the Sleeman Sports Complex in the suburb of Chandler, where a new indoor cycling velodrome (Anna Meares Velodrome) was built. The Velodrome's seat capacity was 4,000 during the games mode.[32]

text: The Shooting disciplines were held at the Belmont Shooting Centre. In Tropical North Queensland, the Cairns Convention Centre and Townsville Entertainment Centre hosted the preliminary rounds of both the men's and women's basketball competitions.[33][34][35]

text: Financing[edit]

text: The Queensland state government spent A$1.5 billion (US$1.2 billion) to deliver the event. Out of this, A$550 million (US$425 million) were spent on the procurement programme. Procurement of the security and security infrastructure included contracts for four prime suppliers which delivered around 4,200 security guards. A$34 million (US$26 million) were spent on the deployment of the armed forces to provide rapid-response squads, bomb detectors, offshore patrols and surveillance. A$657 million (US$509 million) were spent for the construction of the venues and the Games Village.[36]

text: Medals[edit]

text: At a charity gala held on 4 November 2017, the medals for the games were officially unveiled. Australian Indigenous artist Delvene Cockatoo-Collins designed the medals, while they were produced by the Royal Australian Mint. The design of the medals was inspired by the coastline of Gold Coast along with Indigenous culture.[37] Furthermore, Cockatoo-Collins mentioned, "the medal design represents soft sand lines which shift with every tide and wave, also symbolic of athletic achievement, The continual change of tide represents the evolution in athletes who are making their mark, Records are made and special moments of elation are celebrated". Approximately 1,500 medals were created to be distributed to the medallists and each measures approximately 63 millimetres in diameter. The medals weigh between 138 and 163 grams.[38]

text: Athletes village[edit]

text: The 2018 Commonwealth Games Athletes Village was located on 59 hectares at Southport, Gold Coast.[39] which provided accommodation and services to 6,600 athletes and officials in 1252 permanent dwellings. There are 1170 one and two bedroom apartments and 82 three bedroom townhouses which will serve as student accommodation to the nearby Griffith University. It offered services like laundry, refreshments and television and computer spaces and four residential pools. The village consisted a gym which was designed with guidance from the Australian Institute of Sport and equipment and the equipment were sponsored by Technogym. Adjoining the gym was the Athlete Recovery Area which provided services like plunge baths, including accessible baths, saunas, massage and consults from the Sports Medical personnel. The Main Dining served over 18,000 meals per day to the athletes during the games. The village also consisted of retail shops, Optus phone store, salon, bar and a games room which featured a number of arcade games, pool tables and game consoles.[40]

text: Queen's baton relay[edit]

text: The Gold Coast 2018 Queen’s Baton Relay was launched on Commonwealth Day, 13 March 2017, on the historic forecourt at Buckingham Palace, signalling the official countdown to the start of the Games. Accompanied by the Duke of Edinburgh and Prince Edward The Earl of Wessex, Her Majesty Queen Elizabeth II heralded the start of the relay by placing her ‘message to the Commonwealth and its athletes’ into the distinctive loop-design Queen’s Baton which then set off on its journey around the globe. It traveled for 388 days, spending time in every nation and territory of the Commonwealth. The Gold Coast 2018 Queen’s Baton Relay was the longest in Commonwealth Games history. Covering 230,000 km over 388 days, the baton made its way through the six Commonwealth regions of Africa, the Americas, the Caribbean, Europe, Asia and Oceania.

text: The baton landed on Australian soil in December 2017 and then spent 100 days travelling through Australia, finishing its journey at the Opening Ceremony on 4 April 2018, where the message was removed from the Baton and read aloud by Charles, Prince of Wales.[41]

text: Transport[edit]

text: During the games period, free public transportation within Queensland region was provided to ticket and accreditation holders. The free transportation services were available on local buses, train and Gold Coast light rail (G:link) services in Gold Coast and on TransLink and Qconnect bus services in Cairns and Townsville.[42] The Gold Coast light rail system, connected a number of the key games venues including the Optus Aquatic Centre, Broadwater Parklands and the Gold Coast Convention & Exhibition Centre with the major accommodation centres of Surfers Paradise and Broadbeach and the Athletes Village at Parklands. An extension to the system was announced in October 2015, connecting the then current terminus at Gold Coast University Hospital to the railway line to Brisbane at Helensvale. The extension opened in December 2017, in time for the games.[43]

text: Anti-doping[edit]

text: The Australian Sports Anti-Doping Authority conducted an anti-doping drive in the months prior to the games, covering around 2500 tests of Australian athletes, as well as 500 tests against international athletes. Three Australians failed drug tests in this process, along with around 20 international athletes, subject to appeal. The Commonwealth Games Federation conducted in-competition testing and, matching protocol at the Olympic Games, launched a sample storage initiative to allow for future testing of samples up to ten years later, should detection technology improve.[44]

text: Sustainability[edit]

text: The Gold Coast 2018 Commonwealth Games Corporation (GOLDOC) delivered the event with a focus on sustainability under the guidance of the ISO 20121 event sustainability management system and the Global Reporting Initiative (GRI) framework Sustainability Reporting Standards.[45] The GOLDOC received the Sustainability Award in the Australian Business Awards 2016 for focusing on sustainable practices and planning in the preparation of the games.[46] The GOLDOC headquarters received the 4 Star Green Star – Interiors PILOT rating from the Green Building Council of Australia. [47] The new Anna Meares Velodrome, built specifically for the games, is the first velodrome in the world to have full LED broadcast-quality lighting that cuts energy consumption by up to 60% and reduces running costs and carbon emissions.[48]

text: Participating teams[edit]

text: There were 71 nations competing at 2018 Commonwealth Games.[49] Maldives were scheduled to participate, but in October 2016 they withdrew from the Commonwealth.[50] The Gambia returned to the Commonwealth Games after being readmitted as a Commonwealth Games Federation member on 31 March 2018.[3]

text:
hideParticipating Commonwealth Games Associations: country name (number of participants)

 Anguilla (12)
 Antigua and Barbuda (17)
 Australia (469) (hosts)
 Bahamas (31)
 Bangladesh (23)
 Barbados (45)
 Belize (12)
 Bermuda (8)
 Botswana (26)
 British Virgin Islands (10)
 Brunei (8)
 Cameroon (40)
 Canada (282)
 Cayman Islands (21)
 Cook Islands (18)
 Cyprus (46)
 Dominica (13)
 England (390)
 Falkland Islands (15)
 Fiji (96)
 The Gambia (6)
 Ghana (71)
 Gibraltar (22)
 Grenada (14)
 Guernsey (31)
 Guyana (23)
 India (216)
 Isle of Man (31)
 Jamaica (106)
 Jersey (33)
 Kenya (136)
 Kiribati (14)
 Lesotho (20)
 Malawi (19)
 Malaysia (177)
 Malta (24)
 Mauritius (54)
 Montserrat (7)
 Mozambique (26)
 Namibia (28)
 Nauru (16)
 New Zealand (251)
 Nigeria (88)
 Niue (19)
 Norfolk Island (18)
 Northern Ireland (90)
 Pakistan (56)
 Papua New Guinea (56)
 Rwanda (17)
 Saint Helena (9)
 Saint Kitts and Nevis (7)
 Saint Lucia (13)
 Saint Vincent and the Grenadines (20)
 Samoa (38)
 Scotland (226)
 Seychelles (25)
 Sierra Leone (24)
 Singapore (59)
 Solomon Islands (14)
 South Africa (194)
 Sri Lanka (79)
 Swaziland (10)
 Tanzania (15)
 Tonga (13)
 Trinidad and Tobago (51)
 Turks and Caicos Islands (7)
 Tuvalu (7)
 Uganda (69)
 Vanuatu (18)
 Wales (213)
 Zambia (36)

text: Number of athletes by team[edit]

text:
showCGF Code
Country
Athletes

AUS
 Australia
469

ENG
 England
390

CAN
 Canada
282

NZL
 New Zealand
251

SCO
 Scotland
226

IND
 India
216

WAL
 Wales
213

RSA
 South Africa
194

MAS
 Malaysia
177

KEN
 Kenya
136

JAM
 Jamaica
106

FIJ
 Fiji
96

NIR
 Northern Ireland
90

NGR
 Nigeria
88

SRI
 Sri Lanka
79

GHA
 Ghana
71

UGA
 Uganda
69

SIN
 Singapore
59

PAK
 Pakistan
56

PNG
 Papua New Guinea

MRI
 Mauritius
54

TTO
 Trinidad and Tobago
51

CYP
 Cyprus
46

BAR
 Barbados
45

CMR
 Cameroon
40

SAM
 Samoa
38

ZAM
 Zambia
36

JEY
 Jersey
33

BAH
 Bahamas
31

GGY
 Guernsey

IOM
 Isle of Man

NAM
 Namibia
28

BOT
 Botswana
26

MOZ
 Mozambique

SEY
 Seychelles
25

MLT
 Malta
24

SLE
 Sierra Leone

BAN
 Bangladesh
23

GUY
 Guyana

GIB
 Gibraltar
22

CAY
 Cayman Islands
21

LES
 Lesotho
20

SVG
 Saint Vincent and the Grenadines

MAW
 Malawi
19

NIU
 Niue

COK
 Cook Islands
18

NFI
 Norfolk Island

VAN
 Vanuatu

ANT
 Antigua and Barbuda
17

RWA
 Rwanda

NRU
 Nauru
16

FAI
 Falkland Islands
15

TAN
 Tanzania

GRN
 Grenada
14

KIR
 Kiribati

SOL
 Solomon Islands

DMA
 Dominica
13

LCA
 Saint Lucia

TGA
 Tonga

AIA
 Anguilla
12

BIZ
 Belize

IVB
 British Virgin Islands
10

SWZ
 Swaziland

SHN
 Saint Helena
9

BER
 Bermuda
8

BRU
 Brunei

MNT
 Montserrat
7

SKN
 Saint Kitts and Nevis

TCA
 Turks and Caicos Islands

TUV
 Tuvalu

GAM
 The Gambia
6

text: Calendar[edit]

text:
OC
Opening ceremony
●
Event competitions
1
Gold medal events
CC
Closing ceremony

text:
April
4
Wed
5
Thu
6
Fri
7
Sat
8
Sun
9
Mon
10
Tue
11
Wed
12
Thu
13
Fri
14
Sat
15
Sun
Events

Ceremonies
OC

CC
N/A

Aquatics
 Diving

3
2
3
2

10

 Swimming

7
9
8
8
9
9

50

 Athletics

5
6
8
7
10
9
9
4
58

 Badminton

●
●
●
●
1
●
●
●
●
●
5
6

 Basketball

●
●
●
●
●
●

●
1
1
2

 Beach volleyball

●
●
●
●
●
●
2

2

 Boxing

●
●
●
●
●
●
●

●
16

16

Cycling

 Mountain biking

2

2

 Road cycling

2

2

4

 Track cycling

6
4
6
4

20

Gymnastics

 Artistic

1
1
2
5
5

14

 Rhythmic

1
1
4

6

 Hockey

●
●
●
●
●
●
●
●
●
2

2

 Lawn bowls

●
●
●
2
2
●
1
2
3

10

 Netball

●
●
●
●
●
●
●
●

●
1
1

 Powerlifting

4

4

 Rugby sevens

●
●
2
2

 Shooting

3
3
3
3
1
3
3

19

 Squash

●
●
●
●
2
●
●
●
●
1
2
5

 Table tennis

●
●
●
1
1
●
●
●
1
4
2
9

 Triathlon

2

3

5

 Weightlifting

3
3
3
3
4

16

 Wrestling

4
4
4

12

Daily medal events

19
17
22
31
33
26
15
24
27
44
17
275

Cumulative total

19
36
58
89
122
148
163
187
214
258
275

April
4th
Wed
5th
Thu
6th
Fri
7th
Sat
8th
Sun
9th
Mon
10th
Tue
11th
Wed
12th
Thu
13th
Fri
14th
Sat
15th
Sun
Total events

text: Sports[edit]

text: The regulations stated that from the 26 approved sports administered by Commonwealth Governing Bodies, a minimum of ten core sports and maximum of seventeen sports must be included in any Commonwealth Games schedule. The approved sports included the 10 core sports: athletics, badminton, boxing, hockey, lawn bowls, netball (for women), rugby sevens, squash, swimming and weightlifting. Integrated disabled competitions were also scheduled for the Games in nine sports: swimming, athletics, cycling, table tennis, powerlifting and lawn bowls. Along with these events for the first time EAD events in triathlon were held, with the medals added to the final tally for each nation. A record 38 para events were contested at these games.[51] On 8 March 2016, beach volleyball was announced as the 18th sport.[52]

text: The program was broadly similar to that of the 2014 Commonwealth Games, with the major changes being the dropping of judo, the reintroduction of basketball, the debut of women's rugby sevens and beach volleyball.[53]

text: On 7 October 2016, it was announced seven new events for women were added to the sport program, meaning there are an equal number of events for men and women. This marks the first time in history that a major multi-sport event has equality in terms of events. In total 275 events in 18 sports are being contested.[54][55]

text: Numbers in parentheses indicate the number of medal events contested in each sport.

text:
Aquatics

 Diving (10) (details)
 Swimming (50) (details)

 Athletics (58) (details)
 Badminton (6) (details)
 Basketball (2) (details)
 Beach volleyball (2) (details)
 Boxing (16) (details)

 Cycling (details)

Mountain biking (2)
Road (4)
Track (20)

 Gymnastics (details)

Artistic (14)
Rhythmic (6)

 Hockey (2) (details)
 Lawn bowls (10) (details)

 Netball (1) (details)
 Rugby sevens (2) (details)
 Shooting (19) (details)
 Squash (5) (details)
 Table tennis (9) (details)
 Triathlon (5) (details)
 Weightlifting (16) (details)

 Powerlifting (4) (details)

 Wrestling (12) (details)

text: Opening ceremony[edit]

text: The opening ceremony was held at Carrara Stadium in the Gold Coast, Australia, between 20:00 and 22:40 AEST, on 4 April 2018. Tickets for the ceremony started at 100 Australian dollars with half price tickets available for children.[56] The Head of the Commonwealth, Queen Elizabeth II, was represented by her son, Charles, Prince of Wales.[57]

text: Parade of Nations[edit]

text: Following tradition, the host of the previous games, Scotland entered first, followed by the rest of the European countries competing.[58] Following this, all countries paraded in alphabetical order from their respective regions. After the European countries entered, countries from Africa, the Americas, Asia, the Caribbean, and lastly Oceania marched in. The host nation of Australia entered last. Each nation was preceded by a placard bearer carrying a sign with the country's name.

text: Closing ceremony[edit]

text: The closing ceremony was held at Carrara Stadium on Sunday 15 April and was produced by Jack Morton Worldwide at a cost of AU$30 million. Australian pop stars Guy Sebastian, Samantha Jade, Dami Im, Ricki Lee and The Veronicas were among the performers along with children's entertainers, The Wiggles.

text: Prince Edward, Earl of Wessex, declared the Games closed and passed the Commonwealth Games flag to Birmingham, England which will host the 2022 Games.[59]

text: Medal table[edit]

text: Only the top ten successful nations are displayed here.

text: The ranking in this table is consistent with International Olympic Committee convention in its published medal tables. By default, the table is ordered by the number of gold medals the athletes from a nation have won (in this context, a "nation" is an entity represented by a Commonwealth Games Association). The number of silver medals is taken into consideration next and then the number of bronze medals. If nations are still tied, equal ranking is given and they are listed alphabetically by their three-letter country code. Australia tops the medal table rank with 80 gold, second England with 45 gold and third India with 26 gold.

text: *   Host nation (Australia)

text:
2018 Commonwealth Games medal table

Rank
CGA
Gold
Silver
Bronze
Total

1
 Australia (AUS)*
80
59
59
198

2
 England (ENG)
45
45
46
136

3
 India (IND)
26
20
20
66

4
 Canada (CAN)
15
40
27
82

5
 New Zealand (NZL)
15
16
15
46

6
 South Africa (RSA)
13
11
13
37

7
 Wales (WAL)
10
12
14
36

8
 Scotland (SCO)
9
13
22
44

9
 Nigeria (NGR)
9
9
6
24

10
 Cyprus (CYP)
8
1
5
14

Total (43 CGAs)
275
276
289
840

text: Broadcasting[edit]

text: NEP Australia was the host broadcaster of the event. It produced high definition coverage of the event and delivered to the rights-holding broadcasters of other nations.[60][61] In Australia, the games were broadcast live on three Seven Network channels - 7HD, 7TWO and 7Mate.[62] In the United Kingdom, BBC provided Commonwealth Games coverage of more than 200 hours across BBC One, BBC Two, BBC Red Button, BBC Sport website, BBC iPlayer and BBC radio.[63] ESPN provided the games coverage for viewers in the USA.[64] Sony Pictures Networks India broadcast the games for the viewers in India on three channels - Sony Six, Sony Ten 2 in English and Sony Ten 3 in Hindi.[65]

text: Flow Sports provided games coverage in the Caribbean countries such as Anguilla, Antigua & Barbuda, Aruba, The Bahamas, Barbados, Bermuda, Bonaire, British Virgin Islands, Cayman Islands, Curacao, Dominica, Dominican Republic, Grenada, Guadeloupe, Guyana, Haiti, Jamaica, Martinique, Montserrat, Netherlands Antilles, Saint Barthelemy, Saint Kitts & Nevis, St. Martin, St. Vincent & the Grenadines, Saint Lucia, Suriname, Trinidad & Tobago and Turks & Caicos. Flow Sports provided coverage of the event on Flow Sports 1, Flow Sports 2 and up to three additional “Flow Sports Extra” channels.[66]

text: The New Zealand government funded Pacific Cooperation Broadcasting Limited (PCBL) broadcast the event on Pasifika TV in the Oceanian countries such as Cook Islands, Fiji, Nauru, Niue, Papua New Guinea, Samoa, Solomon Islands, Tonga, Vanuatu, Kiribati and Tuvalu.[67]

text:
Territory
Rights holder
Ref

 Australia
Seven Network
[62]

 Canada
DAZN
[68]

Caribbean
Flow
[66]

 India
Sony Pictures Networks India
[65]

 Malaysia
Astro Arena
[69]

 New Zealand
TVNZ
[70]

Oceania
PCBL
[67]

 Singapore
Mediacorp
[71]

 South Africa
SuperSport
[72]

 United Kingdom
BBC
[63]

 United States
ESPN
[64]

text: Marketing[edit]

text: Motto[edit]

text: The official motto for the 2018 Commonwealth Games was "Share the Dream". It was chosen to highlight the dreams and experience at the games that were shared by participants of the games, ranging from athletes to volunteers and the host country Australia to the world including the Commonwealth nations.[73]

text: Emblem[edit]

text: The emblem was launched on 4 April 2013, which marked exactly five years until its opening ceremony.[74] It was unveiled at the Southport Broadwater Parklands. It was designed by the New South Wales based brand consultancy WiteKite.[75] The emblem of the 2018 Commonwealth Games was a silhouette of the skyline and landscape of Gold Coast, the host city of the games.[76] Nigel Chamier OAM, who served as the Chairman of the Gold Coast 2018 Commonwealth Games Corporation till the end of the games, said that it was the result of months of market research.[77]

text: Mascot[edit]

text: Borobi was named as the mascot of the 2018 Commonwealth Games in 2016. Borobi is a blue koala, with indigenous markings on its body. The term "borobi" means koala in the Yugambeh language, spoken by the indigenous Yugambeh people of the Gold Coast and surrounding areas.[78] The song ''Days of Gold'' composed by the Australian Duo band Busby Marou, which was released on 17 October 2014, was considered as the official song of the Mascot Borobi.[79]

text: Sponsors[edit]

text: The official partners of the games were The Star Gold Coast, Griffith University, TAFE Queensland, Longines, Optus, Atos and Woolworths Supermarkets.[80] Griffith University was also also the Creative Arts partner of the games and Presenting partner of the Gold Coast Marathon.[81] TAFE Queensland was responsible for providing vocational education and training program for the volunteers of the games.[82] Longines served as the official timekeeper of the games.[83]

text: Official song[edit]

text: The official song of the 2018 Commonwealth Games ''Welcome to Earth'' was recorded by the Australian Singer Delta Goodrem. The song was performed for the first time by Goodrem during the opening ceremony of the games.[84] The song was worldwide released on 5 April 2018 in Delta Goodrem's official Youtube channel.[85]

text: Concerns and controversies[edit]

text: Missing athletes[edit]

text: At least 13 athletes from four countries - Cameroon, Uganda, Rwanda, and Sierra Leone - absconded during or immediately after the Games. Some missed their competitions.[86] Athletes regularly abscond during major sporting events, and many subsequently claim asylum in their host countries. Most hold nationalities that are deemed high-risk by immigration authorities and find it impossible to get visas outside of exceptional events, such as major games.[87]

text: A month after the games ended, officals estimated that fifty athletes had remained in Australia illegally, with another 200 staying in the country on visas.[88][89]

text: Criticism of the closing ceremony[edit]

text: The organising committee decided to bring in the athletes before the start of the closing ceremony. This caused an uproar on social media as, contrary to public expectations, none of the athletes were shown entering the stadium during the ceremony. Broadcast rights holders Channel 7 complained on air about the decision and concluded that, "it hasn't really lived up to expectations". Many spectators and athletes left during the ceremony, resulting in a half-empty stadium for much of the event.[90] Following this, the ABC claimed that Channel 7 was briefed on the closing ceremony schedule,[91] a claim which Channel 7 later refuted.[92]


document_title: Mount Konocti

question_text: when was the last time mount konocti erupted

text: Mount Konocti

text: Geography[edit]

text: The volcano is the most visible landmark in Lake County other than the lake. The mountain is located between the towns of Lakeport and Clearlake. It lies directly south of Soda Bay and Riviera Heights and east of Kelseyville. Konocti Harbor and Soda Bay sit at the base of the mountain. From the summit of Mount Konocti, the taller peaks and ridges around Snow Mountain can be seen to the northeast.

text: Mount Konocti has five distinctive peaks: Wright Peak (4,299 feet or 1,310 meters), Howard Peak (4,286 ft or 1,306 m), South Peak (4,286 ft or 1,306 m), Buckingham Peak (3,967 ft or 1,209 m) and Clark Peak (2,880 ft or 880 m). Wright Peak, Howard Peak, and South Peak make up the main part of the mountain, while Buckingham Peak and Clark Peak are located off to the side. Konocti Road runs about 4 miles (6.4 km) west from the Taylor Planetarium & Observatory in the town of Kelseyville, snaking between Howard and South Peaks and ending at the mountain's summit, Wright Peak.

text: Benson Ridge lies to the south of Clark Peak and west of South Peak. Buckingham Peak lies north of Howard and Wright Peaks and northeast of Clark Peak. South Peak is directly south of Howard Peak and southwest of Wright Peak. Wright Peak lies east and a little north of Howard Peak.

text: History[edit]

text: Mount Konocti probably first erupted some 350,000 years ago and last erupted 11,000 years ago. Mount Konocti has an explosive, eruptive history with devastating lava flows ending about 13,000 years ago that formed the mountains from Clearlake Oaks to Ukiah, all of which now are covered by trees so the ancient flows are really hard to find.[4] Clear Lake is much older and is possibly the oldest securely dated lake in North America. Core samples taken by U.S. Geological Survey geologists in 1973 and 1980 have been dated to 480,000 years.[citation needed]

text: Archaeologists have found evidence that native people, principally Pomo people and Wappo, have inhabited the area around Konocti for as much as 11,000 years.[citation needed] The name "Konocti" is derived from the Pomo "kno", mountain, and "htai", woman.[6]

text: The mountain is covered with heavy concentrations of chaparral similar to the European maquis shrubland. Oak, Pacific madrone, manzanita, western white pine and other plant species of the California coastal mountains dominate the area. On the northeast slope of Mount Konocti is a steep, heavily forested area known locally as the "Black Forest", because it never gets direct sunshine. The Black Forest contains heavy stands of Douglas fir.

text: Local people have long known that Konocti is riddled with natural caves. Although most of the natural caves collapsed or were filled in for safety in the early 20th century, persistent local belief holds that Konocti's central magma chamber is a vast, empty vertical cavern, partly filled with Clear Lake water and connecting with the lake via an underground seep. This cavern might be the largest on Earth, though its existence is difficult to prove due to the unstable and eroding structure of the volcano's cone. Heavy vegetation also conceals cave entrances. No accurate map or survey of the caves has been created due to the heavy underbrush and unstable hillsides. The majority of Konocti is owned by private parties, who have discouraged exploration and study of the mountain in recent years. The County of Lake recently purchased 1,520 acres on top of the mountain. As a result, Mt. Konocti County Park opened to the public on September 24, 2011.[7]

text: Pomo legend has it that around the year 1818, after a long drought, the level of Clear Lake dropped so low that a previously unknown cave on the eastern flank of Konocti was exposed. A group of Pomo men entered the cave, and discovered a vast underground lake, containing "blind fish". Repeated attempts by divers to locate this cave have been unsuccessful.[8]

text: Although the peak of Konocti was owned privately for a long time, it was acquired by Lake County in 2009. It is now called the Mount Konocti County Park, and is open to the public.[9]

text: Geological status[edit]

text: The U.S. Geological Survey classifies the Clear Lake Volcanic Field, of which Mount Konocti is the most prominent volcano, as High Threat Potential.[4]


document_title: Earth

question_text: what is the diameter of the earth in km

question_tokens: what is the diameter of the earth in km

text: Earth

text: Name and etymology

text: 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 (gē): 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]

text: 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]

text: Chronology

text: Formation

text: The oldest material found in the Solar System is dated to 7000456720000000000♠4.5672±0.0006 billion years ago (Bya).[51] By 7000454000000000000♠4.54±0.04 Bya[52] the primordial Earth had formed. The formation and evolution of Solar System bodies occurred along with the Sun. In theory, a solar nebula partitions a volume out of a molecular cloud by gravitational collapse, which begins to spin and flatten into a circumstellar disk, and then the planets grow out of that disk along with the Sun. A nebula contains gas, ice grains, and dust (including primordial nuclides). According to nebular theory, planetesimals formed by accretion, with the primordial Earth taking 10–7001200000000000000♠20 million years (Mys) to form.[53]

text: A subject of on-going research is the formation of the Moon, some 4.53 Bya.[54] A working hypothesis is that it was formed by accretion from material loosed from Earth after a Mars-sized object, named Theia, impacted Earth.[55] In this scenario, the mass of Theia was approximately 10% of that of Earth,[56] it impacted Earth with a glancing blow,[57] and some of its mass merged with Earth. Between approximately 4.1 and 7000380000000000000♠3.8 Bya, numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of the Moon, and by inference, to that of Earth.

text: Geological history

text: Earth's atmosphere and oceans were formed by volcanic activity and outgassing that included water vapor. The origin of the world's oceans was condensation augmented by water and ice delivered by asteroids, protoplanets, and comets.[58] In this model, atmospheric "greenhouse gases" kept the oceans from freezing when the newly forming Sun had only 70% of its current luminosity.[59] By 7000350000000000000♠3.5 Bya, Earth's magnetic field was established, which helped prevent the atmosphere from being stripped away by the solar wind.[60]

text: A crust formed when the molten outer layer of Earth cooled to form a solid. The two models[61] that explain land mass propose either a steady growth to the present-day forms[62] or, more likely, a rapid growth[63] early in Earth history[64] followed by a long-term steady continental area.[65][66][67] Continents formed by plate tectonics, a process ultimately driven by the continuous loss of heat from Earth's interior. On time scales lasting hundreds of millions of years, the supercontinents have assembled and broken apart. Roughly 7002750000000000000♠750 million years ago (Mya), one of the earliest known supercontinents, Rodinia, began to break apart. The continents later recombined to form Pannotia, 600–7002540000000000000♠540 Mya, then finally Pangaea, which also broke apart 7002180000000000000♠180 Mya.[68]

text: The present pattern of ice ages began about 7001400000000000000♠40 Mya and then intensified during the Pleistocene about 7000300000000000000♠3 Mya. High-latitude regions have since undergone repeated cycles of glaciation and thaw, repeating about every 40,000–7012315576000000000♠100000 years. The last continental glaciation ended 10,000 years ago.[69]

text: Origin of life and evolution

text: Chemical reactions led to the first self-replicating molecules about four billion years ago. A half billion years later, the last common ancestor of all life arose.[70] The evolution of photosynthesis allowed the Sun's energy to be harvested directly by life forms. The resultant molecular oxygen (O2) accumulated in the atmosphere and due to interaction with ultraviolet solar radiation, formed a protective ozone layer (O3) in the upper atmosphere.[71] The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes.[72] True multicellular organisms formed as cells within colonies became increasingly specialized. Aided by the absorption of harmful ultraviolet radiation by the ozone layer, life colonized Earth's surface.[73] Among the earliest fossil evidence for life is microbial mat fossils found in 3.48 billion-year-old sandstone in Western Australia,[74][75][76][77][78] biogenic graphite found in 3.7 billion-year-old metasedimentary rocks in Western Greenland,[79] remains of biotic material found in 4.1 billion-year-old rocks in Western Australia.[30][31]

text: During the Neoproterozoic, 7002750000000000000♠750 to 580 Mya, much of Earth might have been covered in ice. This hypothesis has been termed "Snowball Earth", and it is of particular interest because it preceded the Cambrian explosion, when multicellular life forms significantly increased in complexity.[80] Following the Cambrian explosion, 7002535000000000000♠535 Mya, there have been five major mass extinctions.[81] The most recent such event was 7001660000000000000♠66 Mya, when an asteroid impact triggered the extinction of the non-avian dinosaurs and other large reptiles, but spared some small animals such as mammals, which then resembled shrews. Over the past 7001660000000000000♠66 Mys, mammalian life has diversified, and several million years ago an African ape-like animal such as Orrorin tugenensis gained the ability to stand upright.[82] This facilitated tool use and encouraged communication that provided the nutrition and stimulation needed for a larger brain, which allowed the evolution of humans. The development of agriculture, and then civilization, led to humans having an influence on Earth and the nature and quantity of other life forms that continues today.[83]

text: Future

text: Earth's expected long-term future is closely tied to that of the Sun. Over the next 7000110000000000000♠1.1 Bys, solar luminosity will increase by 10%, and over the next 7000350000000000000♠3.5 Bys by 40%.[84] The Earth's increasing surface temperature will accelerate the inorganic CO2 cycle, reducing its concentration to levels lethally low for plants (6995099999999999999♠10 ppm for C4 photosynthesis) in approximately 500–7002900000000000000♠900 Mys.[85] The lack of vegetation will result in the loss of oxygen in the atmosphere, and animal life will become extinct.[86] After another billion years all surface water will have disappeared[87] and the mean global temperature will reach 7002343150000000000♠70 °C[86] (7002343150000000000♠158 °F). From that point, the Earth is expected to be habitable for another 7016157788000000000♠500 Ma,[85] possibly up to 7016725824800000000♠2.3 Ga if nitrogen is removed from the atmosphere.[88] Even if the Sun were eternal and stable, 27% of the water in the modern oceans will descend to the mantle in one billion years, due to reduced steam venting from mid-ocean ridges.[89]

text: The Sun will evolve to become a red giant in about 7000500000000000000♠5 Bys. Models predict that the Sun will expand to roughly 1 AU (150 million km; 93 million mi), which is about 250 times its present radius.[84][90] Earth's fate is less clear. As a red giant, the Sun will lose roughly 30% of its mass, so, without tidal effects, Earth will move to an orbit 1.7 AU (250 million km; 160 million mi) from the Sun when the star reaches its maximum radius. Most, if not all, remaining life will be destroyed by the Sun's increased luminosity (peaking at about 5,000 times its present level).[84] A 2008 simulation indicates that Earth's orbit will eventually decay due to tidal effects and drag, causing it to enter the Sun's atmosphere and be vaporized.[90]

text: Physical characteristics

text: Shape

text: The shape of Earth is approximately oblate spheroidal. Due to rotation, the Earth is flattened along the geographic axis and bulging around the equator.[92] The diameter of the Earth at the equator is 43 kilometres (27 mi) larger than the pole-to-pole diameter.[93] Thus the point on the surface farthest from Earth's center of mass is the summit of the equatorial Chimborazo volcano in Ecuador.[94][95][96][97] The average diameter of the reference spheroid is 12,742 kilometres (7,918 mi). Local topography deviates from this idealized spheroid, although on a global scale these deviations are small compared to Earth's radius: The maximum deviation of only 0.17% is at the Mariana Trench (10,911 metres (35,797 ft) below local sea level), whereas Mount Everest (8,848 metres (29,029 ft) above local sea level) represents a deviation of 0.14%.[n 13]

text: In geodesy, the exact shape that Earth's oceans would adopt in the absence of land and perturbations such as tides and winds is called the geoid. More precisely, the geoid is the surface of gravitational equipotential at mean sea level.

text: Chemical composition

text:
Chemical composition of the crust[99]

Compound
Formula
Composition

Continental
Oceanic

silica
SiO2
60.2%
48.6%

alumina
Al2O3
15.2%
16.5%

lime
CaO
5.5%
12.3%

magnesia
MgO
3.1%
6.8%

iron(II) oxide
FeO
3.8%
6.2%

sodium oxide
Na2O
3.0%
2.6%

potassium oxide
K2O
2.8%
0.4%

iron(III) oxide
Fe2O3
2.5%
2.3%

water
H2O
1.4%
1.1%

carbon dioxide
CO2
1.2%
1.4%

titanium dioxide
TiO2
0.7%
1.4%

phosphorus pentoxide
P2O5
0.2%
0.3%

Total
99.6%
99.9%

text: Earth's mass is approximately 7024597000000000000♠5.97×1024 kg (5,970 Yg). It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%), with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is estimated to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements.[100]

text: The most common rock constituents of the crust are nearly all oxides: chlorine, sulfur, and fluorine are the important exceptions to this and their total amount in any rock is usually much less than 1%. Over 99% of the crust is composed of 11 oxides, principally silica, alumina, iron oxides, lime, magnesia, potash, and soda.[99][100][101]

text: Internal structure

text: Earth's interior, like that of the other terrestrial planets, is divided into layers by their chemical or physical (rheological) properties. The outer layer is a chemically distinct silicate solid crust, which is underlain by a highly viscous solid mantle. The crust is separated from the mantle by the Mohorovičić discontinuity. The thickness of the crust varies from about 7003600000000000000♠6 km (kilometers) under the oceans to 30–50 km for the continents. The crust and the cold, rigid, top of the upper mantle are collectively known as the lithosphere, and it is of the lithosphere that the tectonic plates are composed. Beneath the lithosphere is the asthenosphere, a relatively low-viscosity layer on which the lithosphere rides. Important changes in crystal structure within the mantle occur at 410 and 7005660000000000000♠660 km below the surface, spanning a transition zone that separates the upper and lower mantle. Beneath the mantle, an extremely low viscosity liquid outer core lies above a solid inner core.[102] The Earth's inner core might rotate at a slightly higher angular velocity than the remainder of the planet, advancing by 0.1–0.5° per year.[103] The radius of the inner core is about one fifth of that of Earth.

text:
Geologic layers of Earth[104]

Earth cutaway from core to exosphere. Not to scale.
Depth[105]
km
Component layer
Density
g/cm3

0–60
Lithosphere[n 14]
—

0–35
Crust[n 15]
2.2–2.9

35–60
Upper mantle
3.4–4.4

  35–2890
Mantle
3.4–5.6

100–700
Asthenosphere
—

2890–5100
Outer core
9.9–12.2

5100–6378
Inner core
12.8–13.1

text: Heat

text: Earth's internal heat comes from a combination of residual heat from planetary accretion (about 20%) and heat produced through radioactive decay (80%).[106] The major heat-producing isotopes within Earth are potassium-40, uranium-238, and thorium-232.[107] At the center, the temperature may be up to 6,000 °C (10,830 °F),[108] and the pressure could reach 360 GPa.[109] Because much of the heat is provided by radioactive decay, scientists postulate that early in Earth's history, before isotopes with short half-lives were depleted, Earth's heat production was much higher. At approximately 7016946728000000000♠3 Ga, twice the present-day heat would have been produced, increasing the rates of mantle convection and plate tectonics, and allowing the production of uncommon igneous rocks such as komatiites that are rarely formed today.[106][110]

text:
Present-day major heat-producing isotopes[111]

Isotope
Heat release
W/kg isotope
Half-life
years
Mean mantle concentration
kg isotope/kg mantle
Heat release
W/kg mantle

238U
94.6 × 10−6
4.47 × 109
30.8 × 10−9
2.91 × 10−12

235U
569 × 10−6
0.704 × 109
0.22 × 10−9
0.125 × 10−12

232Th
26.4 × 10−6
14.0 × 109
124 × 10−9
3.27 × 10−12

40K
29.2 × 10−6
1.25 × 109
36.9 × 10−9
1.08 × 10−12

text: The mean heat loss from Earth is 87 mW m−2, for a global heat loss of 4.42 × 1013 W.[112] A portion of the core's thermal energy is transported toward the crust by mantle plumes, a form of convection consisting of upwellings of higher-temperature rock. These plumes can produce hotspots and flood basalts.[113] More of the heat in Earth is lost through plate tectonics, by mantle upwelling associated with mid-ocean ridges. The final major mode of heat loss is through conduction through the lithosphere, the majority of which occurs under the oceans because the crust there is much thinner than that of the continents.[114]

text: Tectonic plates

text:
Earth's major plates[115]

Plate name
Area
106 km2

  Pacific Plate

103.3

  African Plate[n 16]

78.0

  North American Plate

75.9

  Eurasian Plate

67.8

  Antarctic Plate

60.9

  Indo-Australian Plate

47.2

  South American Plate

43.6

text: The mechanically rigid outer layer of Earth, the lithosphere, is divided into pieces called tectonic plates. These plates are rigid segments that move in relation to one another at one of three types of plate boundaries: convergent boundaries, at which two plates come together, divergent boundaries, at which two plates are pulled apart, and transform boundaries, in which two plates slide past one another laterally. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation can occur along these plate boundaries.[116] The tectonic plates ride on top of the asthenosphere, the solid but less-viscous part of the upper mantle that can flow and move along with the plates.[117]

text: As the tectonic plates migrate, oceanic crust is subducted under the leading edges of the plates at convergent boundaries. At the same time, the upwelling of mantle material at divergent boundaries creates mid-ocean ridges. The combination of these processes recycles the oceanic crust back into the mantle. Due to this recycling, most of the ocean floor is less than 7015315576000000000♠100 Ma old in age. The oldest oceanic crust is located in the Western Pacific and has an estimated age of 7015631152000000000♠200 Ma.[118][119] By comparison, the oldest dated continental crust is 7017127177128000000♠4030 Ma.[120]

text: The seven major plates are the Pacific, North American, Eurasian, African, Antarctic, Indo-Australian, and South American. Other notable plates include the Arabian Plate, the Caribbean Plate, the Nazca Plate off the west coast of South America and the Scotia Plate in the southern Atlantic Ocean. The Australian Plate fused with the Indian Plate between 50 and 7001550000000000000♠55 Mya. The fastest-moving plates are the oceanic plates, with the Cocos Plate advancing at a rate of 75 mm/year[121] and the Pacific Plate moving 52–69 mm/year. At the other extreme, the slowest-moving plate is the Eurasian Plate, progressing at a typical rate of 21 mm/year.[122]

text: Surface

text: The total surface area of the Earth is about 7008510000000000000♠510 million km2 (197 million sq mi).[13] Of this, 70.8%,[13] or 7008361130000000000♠361.13 million km2 (139.43 million sq mi), is below sea level and covered by ocean water.[123] Below the ocean's surface are much of the continental shelf, mountains, volcanoes,[93] oceanic trenches, submarine canyons, oceanic plateaus, abyssal plains, and a globe-spanning mid-ocean ridge system. The remaining 29.2% (7008148940000000000♠148.94 million km2, or 57.51 million sq mi) not covered by water has terrain that varies greatly from place to place and consists of mountains, deserts, plains, plateaus, and other landforms. Tectonics and erosion, volcanic eruptions, flooding, weathering, glaciation, the growth of coral reefs, and meteorite impacts are among the processes that constantly reshape the Earth's surface over geological time.[124][125]

text: The continental crust consists of lower density material such as the igneous rocks granite and andesite. Less common is basalt, a denser volcanic rock that is the primary constituent of the ocean floors.[126] Sedimentary rock is formed from the accumulation of sediment that becomes buried and compacted together. Nearly 75% of the continental surfaces are covered by sedimentary rocks, although they form about 5% of the crust.[127] The third form of rock material found on Earth is metamorphic rock, which is created from the transformation of pre-existing rock types through high pressures, high temperatures, or both. The most abundant silicate minerals on Earth's surface include quartz, feldspars, amphibole, mica, pyroxene and olivine.[128] Common carbonate minerals include calcite (found in limestone) and dolomite.[129]

text: The elevation of the land surface varies from the low point of −418 m at the Dead Sea, to a maximum altitude of 8,848 m at the top of Mount Everest. The mean height of land above sea level is about 797 metres (2,615 ft)[130].

text: The pedosphere is the outermost layer of Earth's continental surface and is composed of soil and subject to soil formation processes. The total arable land is 10.9% of the land surface, with 1.3% being permanent cropland.[131][132] Close to 40% of Earth's land surface is used for cropland and pasture, or an estimated 1.3×107 km2 of cropland and 3.4×107 km2 of pastureland.[133]

text: Hydrosphere

text: The abundance of water on Earth's surface is a unique feature that distinguishes the "Blue Planet" from other planets in the Solar System. Earth's hydrosphere consists chiefly of the oceans, but technically includes all water surfaces in the world, including inland seas, lakes, rivers, and underground waters down to a depth of 2,000 m. The deepest underwater location is Challenger Deep of the Mariana Trench in the Pacific Ocean with a depth of 10,911.4 m.[n 17][134]

text: The mass of the oceans is approximately 1.35×1018 metric tons or about 1/4400 of Earth's total mass. The oceans cover an area of 7014361800000000000♠3.618×108 km2 with a mean depth of 7003368200000000000♠3682 m, resulting in an estimated volume of 7018133200000000000♠1.332×109 km3.[135] If all of Earth's crustal surface were at the same elevation as a smooth sphere, the depth of the resulting world ocean would be 2.7 to 2.8 km.[136][137]

text: About 97.5% of the water is saline; the remaining 2.5% is fresh water. Most fresh water, about 68.7%, is present as ice in ice caps and glaciers.[138]

text: The average salinity of Earth's oceans is about 35 grams of salt per kilogram of sea water (3.5% salt).[139] Most of this salt was released from volcanic activity or extracted from cool igneous rocks.[140] The oceans are also a reservoir of dissolved atmospheric gases, which are essential for the survival of many aquatic life forms.[141] Sea water has an important influence on the world's climate, with the oceans acting as a large heat reservoir.[142] Shifts in the oceanic temperature distribution can cause significant weather shifts, such as the El Niño-Southern Oscillation.[143]

text: Atmosphere

text: The atmospheric pressure on Earth's surface averages 101.325 kPa, with a scale height of about 8.5 km.[3] It has a composition of 78% nitrogen and 21% oxygen, with trace amounts of water vapor, carbon dioxide, and other gaseous molecules. The height of the troposphere varies with latitude, ranging between 8 km at the poles to 17 km at the equator, with some variation resulting from weather and seasonal factors.[144]

text: Earth's biosphere has significantly altered its atmosphere. Oxygenic photosynthesis evolved 7000270000000000000♠2.7 Gya, forming the primarily nitrogen–oxygen atmosphere of today.[71] This change enabled the proliferation of aerobic organisms and, indirectly, the formation of the ozone layer due to the subsequent conversion of atmospheric O2 into O3. The ozone layer blocks ultraviolet solar radiation, permitting life on land.[145] Other atmospheric functions important to life include transporting water vapor, providing useful gases, causing small meteors to burn up before they strike the surface, and moderating temperature.[146] This last phenomenon is known as the greenhouse effect: trace molecules within the atmosphere serve to capture thermal energy emitted from the ground, thereby raising the average temperature. Water vapor, carbon dioxide, methane, nitrous oxide, and ozone are the primary greenhouse gases in the atmosphere. Without this heat-retention effect, the average surface temperature would be −18 °C, in contrast to the current +15 °C,[147] and life on Earth probably would not exist in its current form.[148] In May 2017, glints of light, seen as twinkling from an orbiting satellite a million miles away, were found to be reflected light from ice crystals in the atmosphere.[149][150]

text: Weather and climate

text: Earth's atmosphere has no definite boundary, slowly becoming thinner and fading into outer space. Three-quarters of the atmosphere's mass is contained within the first 11 km (6.8 mi) of the surface. This lowest layer is called the troposphere. Energy from the Sun heats this layer, and the surface below, causing expansion of the air. This lower-density air then rises and is replaced by cooler, higher-density air. The result is atmospheric circulation that drives the weather and climate through redistribution of thermal energy.[151]

text: The primary atmospheric circulation bands consist of the trade winds in the equatorial region below 30° latitude and the westerlies in the mid-latitudes between 30° and 60°.[152] Ocean currents are also important factors in determining climate, particularly the thermohaline circulation that distributes thermal energy from the equatorial oceans to the polar regions.[153]

text: Water vapor generated through surface evaporation is transported by circulatory patterns in the atmosphere. When atmospheric conditions permit an uplift of warm, humid air, this water condenses and falls to the surface as precipitation.[151] Most of the water is then transported to lower elevations by river systems and usually returned to the oceans or deposited into lakes. This water cycle is a vital mechanism for supporting life on land and is a primary factor in the erosion of surface features over geological periods. Precipitation patterns vary widely, ranging from several meters of water per year to less than a millimeter. Atmospheric circulation, topographic features, and temperature differences determine the average precipitation that falls in each region.[154]

text: The amount of solar energy reaching Earth's surface decreases with increasing latitude. At higher latitudes, the sunlight reaches the surface at lower angles, and it must pass through thicker columns of the atmosphere. As a result, the mean annual air temperature at sea level decreases by about 0.4 °C (0.7 °F) per degree of latitude from the equator.[155] Earth's surface can be subdivided into specific latitudinal belts of approximately homogeneous climate. Ranging from the equator to the polar regions, these are the tropical (or equatorial), subtropical, temperate and polar climates.[156]

text: This latitudinal rule has several anomalies:

text:
Proximity to oceans moderates the climate. For example, the Scandinavian Peninsula has more moderate climate than similarly northern latitudes of northern Canada.
The wind enables this moderating effect. The windward side of a land mass experiences more moderation than the leeward side. In the Northern Hemisphere, the prevailing wind is west-to-east, and western coasts tend to be milder than eastern coasts. This is seen in Eastern North America and Western Europe, where rough continental climates appear on the east coast on parallels with mild climates on the other side of the ocean.[157] In the Southern Hemisphere, the prevailing wind is east-to-west, and the eastern coasts are milder.
The distance from the Earth to the Sun varies. The Earth is closest to the Sun (at perihelion) in January, which is summer in the Southern Hemisphere. It is furthest away (at aphelion) in July, which is summer in the Northern Hemisphere, and only 93.55% of the solar radiation from the Sun falls on a given square area of land than at perihelion. Despite this, there are larger land masses in the Northern Hemisphere, which are easier to heat than the seas. Consequently, summers are 2.3 °C (4 °F) warmer in the Northern Hemisphere than in the Southern Hemisphere under similar conditions.[158]
The climate is colder at high altitudes than at sea level because of the decreased air density.

tag: ul

text: The commonly used Köppen climate classification system has five broad groups (humid tropics, arid, humid middle latitudes, continental and cold polar), which are further divided into more specific subtypes.[152] The Köppen system rates regions of terrain based on observed temperature and precipitation.

text: The highest air temperature ever measured on Earth was 56.7 °C (134.1 °F) in Furnace Creek, California, in Death Valley, in 1913.[159] The lowest air temperature ever directly measured on Earth was −89.2 °C (−128.6 °F) at Vostok Station in 1983,[160] but satellites have used remote sensing to measure temperatures as low as −94.7 °C (−138.5 °F) in East Antarctica.[161] These temperature records are only measurements made with modern instruments from the 20th century onwards and likely do not reflect the full range of temperature on Earth.

text: Upper atmosphere

text: Above the troposphere, the atmosphere is usually divided into the stratosphere, mesosphere, and thermosphere.[146] Each layer has a different lapse rate, defining the rate of change in temperature with height. Beyond these, the exosphere thins out into the magnetosphere, where the geomagnetic fields interact with the solar wind.[162] Within the stratosphere is the ozone layer, a component that partially shields the surface from ultraviolet light and thus is important for life on Earth. The Kármán line, defined as 100 km above Earth's surface, is a working definition for the boundary between the atmosphere and outer space.[163]

text: Thermal energy causes some of the molecules at the outer edge of the atmosphere to increase their velocity to the point where they can escape from Earth's gravity. This causes a slow but steady loss of the atmosphere into space. Because unfixed hydrogen has a low molecular mass, it can achieve escape velocity more readily, and it leaks into outer space at a greater rate than other gases.[164] The leakage of hydrogen into space contributes to the shifting of Earth's atmosphere and surface from an initially reducing state to its current oxidizing one. Photosynthesis provided a source of free oxygen, but the loss of reducing agents such as hydrogen is thought to have been a necessary precondition for the widespread accumulation of oxygen in the atmosphere.[165] Hence the ability of hydrogen to escape from the atmosphere may have influenced the nature of life that developed on Earth.[166] In the current, oxygen-rich atmosphere most hydrogen is converted into water before it has an opportunity to escape. Instead, most of the hydrogen loss comes from the destruction of methane in the upper atmosphere.[167]

text: Gravitational field

text: The gravity of Earth is the acceleration that is imparted to objects due to the distribution of mass within the Earth. Near the Earth's surface, gravitational acceleration is approximately 9.8 m/s2 (32 ft/s2). Local differences in topography, geology, and deeper tectonic structure cause local and broad, regional differences in the Earth's gravitational field, known as gravitational anomalies.[168]

text: Magnetic field

text: The main part of Earth's magnetic field is generated in the core, the site of a dynamo process that converts the kinetic energy of thermally and compositionally driven convection into electrical and magnetic field energy. The field extends outwards from the core, through the mantle, and up to Earth's surface, where it is, approximately, a dipole. The poles of the dipole are located close to Earth's geographic poles. At the equator of the magnetic field, the magnetic-field strength at the surface is 3.05 × 10−5 T, with global magnetic dipole moment of 7.91 × 1015 T m3.[169] The convection movements in the core are chaotic; the magnetic poles drift and periodically change alignment. This causes secular variation of the main field and field reversals at irregular intervals averaging a few times every million years. The most recent reversal occurred approximately 700,000 years ago.[170][171]

text: Magnetosphere

text: The extent of Earth's magnetic field in space defines the magnetosphere. Ions and electrons of the solar wind are deflected by the magnetosphere; solar wind pressure compresses the dayside of the magnetosphere, to about 10 Earth radii, and extends the nightside magnetosphere into a long tail.[172] Because the velocity of the solar wind is greater than the speed at which wave propagate through the solar wind, a supersonic bowshock precedes the dayside magnetosphere within the solar wind.[173] Charged particles are contained within the magnetosphere; the plasmasphere is defined by low-energy particles that essentially follow magnetic field lines as Earth rotates;[174][175] the ring current is defined by medium-energy particles that drift relative to the geomagnetic field, but with paths that are still dominated by the magnetic field,[176] and the Van Allen radiation belt are formed by high-energy particles whose motion is essentially random, but otherwise contained by the magnetosphere.[172][177]

text: During magnetic storms and substorms, charged particles can be deflected from the outer magnetosphere and especially the magnetotail, directed along field lines into Earth's ionosphere, where atmospheric atoms can be excited and ionized, causing the aurora.[178]

text: Orbit and rotation

text: Rotation

text: Earth's rotation period relative to the Sun—its mean solar day—is 86,400 seconds of mean solar time (86,400.0025 SI seconds).[179] Because Earth's solar day is now slightly longer than it was during the 19th century due to tidal deceleration, each day varies between 0 and 2 SI ms longer.[180][181]

text: Earth's rotation period relative to the fixed stars, called its stellar day by the International Earth Rotation and Reference Systems Service (IERS), is 86,164.0989 seconds of mean solar time (UT1), or 23h 56m 4.0989s.[2][n 18] Earth's rotation period relative to the precessing or moving mean vernal equinox, misnamed its sidereal day, is 86,164.0905 seconds of mean solar time (UT1) (23h 56m 4.0905s).[2] Thus the sidereal day is shorter than the stellar day by about 8.4 ms.[182] The length of the mean solar day in SI seconds is available from the IERS for the periods 1623–2005[183] and 1962–2005.[184]

text: Apart from meteors within the atmosphere and low-orbiting satellites, the main apparent motion of celestial bodies in Earth's sky is to the west at a rate of 15°/h = 15'/min. For bodies near the celestial equator, this is equivalent to an apparent diameter of the Sun or the Moon every two minutes; from Earth's surface, the apparent sizes of the Sun and the Moon are approximately the same.[185][186]

text: Orbit

text: Earth orbits the Sun at an average distance of about 150 million km (93 million mi) every 365.2564 mean solar days, or one sidereal year. This gives an apparent movement of the Sun eastward with respect to the stars at a rate of about 1°/day, which is one apparent Sun or Moon diameter every 12 hours. Due to this motion, on average it takes 24 hours—a solar day—for Earth to complete a full rotation about its axis so that the Sun returns to the meridian. The orbital speed of Earth averages about 29.78 km/s (107,200 km/h; 66,600 mph), which is fast enough to travel a distance equal to Earth's diameter, about 12,742 km (7,918 mi), in seven minutes, and the distance to the Moon, 384,000 km (239,000 mi), in about 3.5 hours.[3]

text: The Moon and Earth orbit a common barycenter every 27.32 days relative to the background stars. When combined with the Earth–Moon system's common orbit around the Sun, the period of the synodic month, from new moon to new moon, is 29.53 days. Viewed from the celestial north pole, the motion of Earth, the Moon, and their axial rotations are all counterclockwise. Viewed from a vantage point above the north poles of both the Sun and Earth, Earth orbits in a counterclockwise direction about the Sun. The orbital and axial planes are not precisely aligned: Earth's axis is tilted some 23.44 degrees from the perpendicular to the Earth–Sun plane (the ecliptic), and the Earth–Moon plane is tilted up to ±5.1 degrees against the Earth–Sun plane. Without this tilt, there would be an eclipse every two weeks, alternating between lunar eclipses and solar eclipses.[3][187]

text: The Hill sphere, or the sphere of gravitational influence, of the Earth is about 1.5 million kilometres (930,000 mi) in radius.[188][n 19] This is the maximum distance at which the Earth's gravitational influence is stronger than the more distant Sun and planets. Objects must orbit the Earth within this radius, or they can become unbound by the gravitational perturbation of the Sun.

text: Earth, along with the Solar System, is situated in the Milky Way and orbits about 28,000 light-years from its center. It is about 20 light-years above the galactic plane in the Orion Arm.[189]

text: Axial tilt and seasons

text: The axial tilt of the Earth is approximately 23.439281°[2] with the axis of its orbit plane, always pointing towards the Celestial Poles. Due to Earth's axial tilt, the amount of sunlight reaching any given point on the surface varies over the course of the year. This causes the seasonal change in climate, with summer in the Northern Hemisphere occurring when the Tropic of Cancer is facing the Sun, and winter taking place when the Tropic of Capricorn in the Southern Hemisphere faces the Sun. During the summer, the day lasts longer, and the Sun climbs higher in the sky. In winter, the climate becomes cooler and the days shorter. In northern temperate latitudes, the Sun rises north of true east during the summer solstice, and sets north of true west, reversing in the winter. The Sun rises south of true east in the summer for the southern temperate zone and sets south of true west.

text: Above the Arctic Circle, an extreme case is reached where there is no daylight at all for part of the year, up to six months at the North Pole itself, a polar night. In the Southern Hemisphere, the situation is exactly reversed, with the South Pole oriented opposite the direction of the North Pole. Six months later, this pole will experience a midnight sun, a day of 24 hours, again reversing with the South Pole.

text: By astronomical convention, the four seasons can be determined by the solstices—the points in the orbit of maximum axial tilt toward or away from the Sun—and the equinoxes, when the direction of the tilt and the direction to the Sun are perpendicular. In the Northern Hemisphere, winter solstice currently occurs around 21 December; summer solstice is near 21 June, spring equinox is around 20 March and autumnal equinox is about 22 or 23 September. In the Southern Hemisphere, the situation is reversed, with the summer and winter solstices exchanged and the spring and autumnal equinox dates swapped.[190]

text: The angle of Earth's axial tilt is relatively stable over long periods of time. Its axial tilt does undergo nutation; a slight, irregular motion with a main period of 18.6 years.[191] The orientation (rather than the angle) of Earth's axis also changes over time, precessing around in a complete circle over each 25,800 year cycle; this precession is the reason for the difference between a sidereal year and a tropical year. Both of these motions are caused by the varying attraction of the Sun and the Moon on Earth's equatorial bulge. The poles also migrate a few meters across Earth's surface. This polar motion has multiple, cyclical components, which collectively are termed quasiperiodic motion. In addition to an annual component to this motion, there is a 14-month cycle called the Chandler wobble. Earth's rotational velocity also varies in a phenomenon known as length-of-day variation.[192]

text: In modern times, Earth's perihelion occurs around 3 January, and its aphelion around 4 July. These dates change over time due to precession and other orbital factors, which follow cyclical patterns known as Milankovitch cycles. The changing Earth–Sun distance causes an increase of about 6.9%[n 20] in solar energy reaching Earth at perihelion relative to aphelion. Because the Southern Hemisphere is tilted toward the Sun at about the same time that Earth reaches the closest approach to the Sun, the Southern Hemisphere receives slightly more energy from the Sun than does the northern over the course of a year. This effect is much less significant than the total energy change due to the axial tilt, and most of the excess energy is absorbed by the higher proportion of water in the Southern Hemisphere.[193]

text: Habitability

text: A planet that can sustain life is termed habitable, even if life did not originate there. Earth provides liquid water—an environment where complex organic molecules can assemble and interact, and sufficient energy to sustain metabolism.[194] The distance of Earth from the Sun, as well as its orbital eccentricity, rate of rotation, axial tilt, geological history, sustaining atmosphere, and magnetic field all contribute to the current climatic conditions at the surface.[195]

text: Biosphere

text: A planet's life forms inhabit ecosystems, whose total is sometimes said to form a "biosphere". Earth's biosphere is thought to have begun evolving about 7000350000000000000♠3.5 Gya.[71] The biosphere is divided into a number of biomes, inhabited by broadly similar plants and animals. On land, biomes are separated primarily by differences in latitude, height above sea level and humidity. Terrestrial biomes lying within the Arctic or Antarctic Circles, at high altitudes or in extremely arid areas are relatively barren of plant and animal life; species diversity reaches a peak in humid lowlands at equatorial latitudes.[196]

text: In July 2016, scientists reported identifying a set of 355 genes from the Last Universal Common Ancestor (LUCA) of all organisms living on Earth.[197]

text: Natural resources and land use

text:
Estimated human land use, 2000[198]

Land use
Mha

Cropland
1,510–1,611

Pastures
2,500–3,410

Natural forests
3,143–3,871

Planted forests
126–215

Urban areas
66–351

Unused, productive land
356–445

text: Earth has resources that have been exploited by humans. Those termed non-renewable resources, such as fossil fuels, only renew over geological timescales.

text: Large deposits of fossil fuels are obtained from Earth's crust, consisting of coal, petroleum, and natural gas. These deposits are used by humans both for energy production and as feedstock for chemical production. Mineral ore bodies have also been formed within the crust through a process of ore genesis, resulting from actions of magmatism, erosion, and plate tectonics.[199] These bodies form concentrated sources for many metals and other useful elements.

text: Earth's biosphere produces many useful biological products for humans, including food, wood, pharmaceuticals, oxygen, and the recycling of many organic wastes. The land-based ecosystem depends upon topsoil and fresh water, and the oceanic ecosystem depends upon dissolved nutrients washed down from the land.[200] In 1980, 5,053 Mha (50.53 million km2) of Earth's land surface consisted of forest and woodlands, 6,788 Mha (67.88 million km2) was grasslands and pasture, and 1,501 Mha (15.01 million km2) was cultivated as croplands.[201] The estimated amount of irrigated land in 1993 was 2,481,250 square kilometres (958,020 sq mi).[14] Humans also live on the land by using building materials to construct shelters.

text: Natural and environmental hazards

text: Large areas of Earth's surface are subject to extreme weather such as tropical cyclones, hurricanes, or typhoons that dominate life in those areas. From 1980 to 2000, these events caused an average of 11,800 human deaths per year.[202] Many places are subject to earthquakes, landslides, tsunamis, volcanic eruptions, tornadoes, sinkholes, blizzards, floods, droughts, wildfires, and other calamities and disasters.

text: Many localized areas are subject to human-made pollution of the air and water, acid rain and toxic substances, loss of vegetation (overgrazing, deforestation, desertification), loss of wildlife, species extinction, soil degradation, soil depletion and erosion.

text: There is a scientific consensus linking human activities to global warming due to industrial carbon dioxide emissions. This is predicted to produce changes such as the melting of glaciers and ice sheets, more extreme temperature ranges, significant changes in weather and a global rise in average sea levels.[203]

text: Human geography

text:
North America
  South America
  Antarctica

  Europe
  Africa

  Asia
  Australia

v
t
e

text: Cartography, the study and practice of map-making, and geography, the study of the lands, features, inhabitants and phenomena on Earth, have historically been the disciplines devoted to depicting Earth. Surveying, the determination of locations and distances, and to a lesser extent navigation, the determination of position and direction, have developed alongside cartography and geography, providing and suitably quantifying the requisite information.

text: Earth's human population reached approximately seven billion on 31 October 2011.[205] Projections indicate that the world's human population will reach 9.2 billion in 2050.[206] Most of the growth is expected to take place in developing nations. Human population density varies widely around the world, but a majority live in Asia. By 2020, 60% of the world's population is expected to be living in urban, rather than rural, areas.[207]

text: It is estimated that one-eighth of Earth's surface is suitable for humans to live on – three-quarters of Earth's surface is covered by oceans, leaving one-quarter as land. Half of that land area is desert (14%),[208] high mountains (27%),[209] or other unsuitable terrains. The northernmost permanent settlement in the world is Alert, on Ellesmere Island in Nunavut, Canada.[210] (82°28′N) The southernmost is the Amundsen–Scott South Pole Station, in Antarctica, almost exactly at the South Pole. (90°S)

text: Independent sovereign nations claim the planet's entire land surface, except for some parts of Antarctica, a few land parcels along the Danube river's western bank, and the unclaimed area of Bir Tawil between Egypt and Sudan. As of 2015[update], there are 193 sovereign states that are member states of the United Nations, plus two observer states and 72 dependent territories and states with limited recognition.[14] Earth has never had a sovereign government with authority over the entire globe, although some nation-states have striven for world domination and failed.[211]

text: The United Nations is a worldwide intergovernmental organization that was created with the goal of intervening in the disputes between nations, thereby avoiding armed conflict.[212] The U.N. serves primarily as a forum for international diplomacy and international law. When the consensus of the membership permits, it provides a mechanism for armed intervention.[213]

text: The first human to orbit Earth was Yuri Gagarin on 12 April 1961.[214] In total, about 487 people have visited outer space and reached orbit as of 30 July 2010[update], and, of these, twelve have walked on the Moon.[215][216][217] Normally, the only humans in space are those on the International Space Station. The station's crew, made up of six people, is usually replaced every six months.[218] The farthest that humans have traveled from Earth is 400,171 km, achieved during the Apollo 13 mission in 1970.[219]

text: Moon

text:
Characteristics

Diameter
3,474.8 km

Mass
7.349×1022 kg

Semi-major axis
384,400 km

Orbital period
27 d 7 h 43.7 m

text: The Moon is a relatively large, terrestrial, planet-like natural satellite, with a diameter about one-quarter of Earth's. It is the largest moon in the Solar System relative to the size of its planet, although Charon is larger relative to the dwarf planet Pluto. The natural satellites of other planets are also referred to as "moons", after Earth's.

text: The gravitational attraction between Earth and the Moon causes tides on Earth. The same effect on the Moon has led to its tidal locking: its rotation period is the same as the time it takes to orbit Earth. As a result, it always presents the same face to the planet. As the Moon orbits Earth, different parts of its face are illuminated by the Sun, leading to the lunar phases; the dark part of the face is separated from the light part by the solar terminator.

text: Due to their tidal interaction, the Moon recedes from Earth at the rate of approximately 38 mm/yr. Over millions of years, these tiny modifications—and the lengthening of Earth's day by about 23 µs/yr—add up to significant changes.[220] During the Devonian period, for example, (approximately 7002410000000000000♠410 Mya) there were 400 days in a year, with each day lasting 21.8 hours.[221]

text: The Moon may have dramatically affected the development of life by moderating the planet's climate. Paleontological evidence and computer simulations show that Earth's axial tilt is stabilized by tidal interactions with the Moon.[28] Some theorists think that without this stabilization against the torques applied by the Sun and planets to Earth's equatorial bulge, the rotational axis might be chaotically unstable, exhibiting chaotic changes over millions of years, as appears to be the case for Mars.[222]

text: Viewed from Earth, the Moon is just far enough away to have almost the same apparent-sized disk as the Sun. The angular size (or solid angle) of these two bodies match because, although the Sun's diameter is about 400 times as large as the Moon's, it is also 400 times more distant.[186] This allows total and annular solar eclipses to occur on Earth.

text: The most widely accepted theory of the Moon's origin, the giant-impact hypothesis, states that it formed from the collision of a Mars-size protoplanet called Theia with the early Earth. This hypothesis explains (among other things) the Moon's relative lack of iron and volatile elements and the fact that its composition is nearly identical to that of Earth's crust.[223]

text: Asteroids and artificial satellites

text: Earth has at least five co-orbital asteroids, including 3753 Cruithne and 2002 AA29.[224][225] A trojan asteroid companion, 2010 TK7, is librating around the leading Lagrange triangular point, L4, in the Earth's orbit around the Sun.[226][227]

text: The tiny near-Earth asteroid 2006 RH120 makes close approaches to the Earth–Moon system roughly every twenty years. During these approaches, it can orbit Earth for brief periods of time.[228]

text: As of June 2016[update], there were 1,419 operational, human-made satellites orbiting Earth.[5] There are also inoperative satellites, including Vanguard 1, the oldest satellite currently in orbit, and over 16,000 pieces of tracked space debris.[n 3] Earth's largest artificial satellite is the International Space Station.

text: Cultural and historical viewpoint

text: The standard astronomical symbol of Earth consists of a cross circumscribed by a circle, ,[229] representing the four corners of the world.

text: Human cultures have developed many views of the planet. Earth is sometimes personified as a deity. In many cultures it is a mother goddess that is also the primary fertility deity,[230] and by the mid-20th century, the Gaia Principle compared Earth's environments and life as a single self-regulating organism leading to broad stabilization of the conditions of habitability.[231][232][233] Creation myths in many religions involve the creation of Earth by a supernatural deity or deities.[230]

text: Scientific investigation has resulted in several culturally transformative shifts in people's view of the planet. In the West, belief in a flat Earth[234] was displaced by the idea of spherical Earth, credited to Pythagoras in the 6th century BC.[235] Earth was further believed to be the center of the universe until the 16th century when scientists first theorized that it was a moving object, comparable to the other planets in the Solar System.[236] Due to the efforts of influential Christian scholars and clerics such as James Ussher, who sought to determine the age of Earth through analysis of genealogies in Scripture, Westerners before the 19th century generally believed Earth to be a few thousand years old at most. It was only during the 19th century that geologists realized Earth's age was at least many millions of years.[237]

text: Lord Kelvin used thermodynamics to estimate the age of Earth to be between 20 million and 400 million years in 1864, sparking a vigorous debate on the subject; it was only when radioactivity and radioactive dating were discovered in the late 19th and early 20th centuries that a reliable mechanism for determining Earth's age was established, proving the planet to be billions of years old.[238][239] The perception of Earth shifted again in the 20th century when humans first viewed it from orbit, and especially with photographs of Earth returned by the Apollo program.[240]