117-402: The World Press Freedom Index ( WPFI ) is an annual ranking of countries compiled and published by Reporters Without Borders (RSF) since 2002 based upon the non-governmental organization 's own assessment of the countries' press freedom records in the previous year. It intends to reflect the degree of freedom that journalists , news organizations, and netizens have in each country, and
234-540: A circumstellar disk , and then the planets grow out of that disk 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 being estimated as likely taking anywhere from 70 to 100 million years to form. Estimates of the age of the Moon range from 4.5 Ga to significantly younger. A leading hypothesis
351-526: A 2005 essay, "Unsettlement": ...What is this thing country? What does country mean? ... I spoke with others who said country meant Home, but who added the caveat that Home resided in people rather than places – a kind of portable Country... I tried to tease out some ways in which non-Indigenous people have understood country. I made categories: Country as Economy. Country as Geography. Country as Society. Country as Myth. Country as History. For all that I walked, slept, breathed and dreamed Country,
468-540: A combination of many different feelings, and language relating to one's homeland, including ethnic, cultural, political, or historical aspects. It encompasses a set of concepts closely related to nationalism , mostly civic nationalism and sometimes cultural nationalism . Several organizations seek to identify trends to produce economy country classifications. Countries are often distinguished as developing countries or developed countries . The United Nations Department of Economic and Social Affairs annually produces
585-492: 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 Sun and Earth's north poles, Earth orbits in
702-548: 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 . The Hill sphere , or
819-649: A country in its own right, called constituent countries. The Danish Realm consists of Denmark proper , the Faroe Islands , and Greenland . The Kingdom of the Netherlands consists of the Netherlands proper , Aruba , Curaçao , and Sint Maarten . The United Kingdom consists of England , Scotland , Wales , and Northern Ireland . Dependent territories are the territories of a sovereign state that are outside of its proper territory. These include
936-420: 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 from Earth to the Moon, 384,400 km (238,900 mi), in about 3.5 hours. The Moon and Earth orbit
1053-421: A globe-spanning mid-ocean ridge system. At Earth's polar regions , the ocean surface is covered by seasonally variable amounts of sea ice that often connects with polar land, permafrost and ice sheets , forming polar ice caps . Earth's land covers 29.2%, or 149 million km (58 million sq mi) of Earth's surface. The land surface includes many islands around the globe, but most of
1170-457: A government not under another, and the capacity to interact with other states. The declarative theory outlined in the 1933 Montevideo Convention describes a state in Article 1 as: The Montevideo Convention in Article 3 implies that a sovereign state can still be a sovereign state even if no other countries recognise that it exists. As a restatement of customary international law ,
1287-412: A number of non-sovereign entities are commonly called countries. No definition is binding on all the members of the community of nations on the criteria for statehood. State practice relating to the recognition of a country typically falls somewhere between the declaratory and constitutive approaches. International law defines sovereign states as having a permanent population, defined territory,
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#17327732120751404-807: A political entity may be referred to as a "country", such as the West Country in England, "big sky country" (used in various contexts of the American West ), "coal country" (used to describe coal-mining regions ), or simply "the country" (used to describe a rural area ). The term "country" is also used as a qualifier descriptively, such as country music or country living . The word country comes from Old French contrée , which derives from Vulgar Latin ( terra ) contrata ("(land) lying opposite"; "(land) spread before"), derived from contra ("against, opposite"). It most likely entered
1521-436: A separate " country of origin " in international trade, such as Hong Kong , Greenland , and Macau . Symbols of a country may incorporate cultural , religious or political symbols of any nation that the country includes. Many categories of symbols can be seen in flags, coats of arms, or seals. Most countries have a long name and a short name. The long name is typically used in formal contexts and often describes
1638-456: 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 6 kilometres (3.7 mi) under the oceans to 30–50 km (19–31 mi) for the continents. The crust and the cold, rigid, top of the upper mantle are collectively known as
1755-485: Is a distinct part of the world , such as a state , nation , or other political entity . When referring to a specific polity, the term "country" may refer to a sovereign state , states with limited recognition , constituent country , or a dependent territory . Most sovereign states, but not all countries, are members of the United Nations . There is no universal agreement on the number of "countries" in
1872-539: Is also used for the sense of native sovereign territory , such as the widespread use of Indian country in the United States. The term "country" in English may also be wielded to describe rural areas , or used in the form "countryside." Raymond Williams , a Welsh scholar, wrote in 1975: 'Country' and 'city' are very powerful words, and this is not surprising when we remember how much they seem to stand for in
1989-480: Is an act of sovereignty pertaining each member of the international community, an act to be taken individually, and it is, therefore, up to member states and each OAU power [to decide] whether to recognise or not the newly independent state. Some countries, such as Taiwan , Sahrawi Republic and Kosovo have disputed sovereignty and/or limited recognition among some countries. Some sovereign states are unions of separate polities, each of which may also be considered
2106-535: Is approximately 9.8 m/s (32 ft/s ). Local differences in topography, geology, and deeper tectonic structure cause local and broad regional differences in Earth's gravitational field, known as gravity anomalies . 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
2223-435: Is at least somewhat humid and covered by vegetation , while large sheets of ice at Earth's polar deserts retain more water than Earth's groundwater , lakes, rivers and atmospheric water combined. Earth's crust consists of slowly moving tectonic plates , which interact to produce mountain ranges, volcanoes , and earthquakes. Earth has a liquid outer core that generates a magnetosphere capable of deflecting most of
2340-518: Is clear that the relationships between 'country' and 'nation' are so different from one [place] to the next as to be impossible to fold into a dichotomous opposition as they are into a promiscuous fusion." Areas much smaller than a political state may be referred to as countries, such as the West Country in England, "big sky country" (used in various contexts of the American West ), "coal country" (used to describe coal-mining regions in several sovereign states) and many other terms. The word "country"
2457-529: Is contained in 3.45 billion-year-old Australian rocks showing fossils of microorganisms . During the Neoproterozoic , 1000 to 539 Ma , 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. Following
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#17327732120752574-457: Is farthest out from its center of mass at its equatorial bulge, the summit of the volcano Chimborazo in Ecuador (6,384.4 km or 3,967.1 mi) is its farthest point out. Parallel to the rigid land topography the ocean exhibits a more dynamic topography . To measure the local variation of Earth's topography, geodesy employs an idealized Earth producing a geoid shape. Such a shape
2691-516: Is gained if the ocean is idealized, covering Earth completely and without any perturbations such as tides and winds. The result is a smooth but irregular geoid surface, providing a mean sea level (MSL) as a reference level for topographic measurements. Earth's surface is the boundary between the atmosphere, and the solid Earth and oceans. Defined in this way, it has an area of about 510 million km (197 million sq mi). Earth can be divided into two hemispheres : by latitude into
2808-413: Is not clear how they should be assessed. We attribute so many different kinds of properties to countries, speaking as though a country can feature wheat fields waving or be girt by sea, can have a founding date and be democratic and free, can be English speaking, culturally diverse, war torn or Islamic. Melissa Lucashenko , an Aboriginal Australian writer, expressed the difficulty of defining "country" in
2925-513: Is now slightly longer than it was during the 19th century due to tidal deceleration , each day varies between 0 and 2 ms longer than the mean solar day. 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 23 56 4.0989 . Earth's rotation period relative to
3042-622: Is rare, though the alternative spelling Gaia has become common due to the Gaia hypothesis , in which case its pronunciation is / ˈ ɡ aɪ . ə / rather than the more classical English / ˈ ɡ eɪ . ə / . There are a number of adjectives for the planet Earth. The word "earthly" is derived from "Earth". From the Latin Terra comes terran / ˈ t ɛr ə n / , terrestrial / t ə ˈ r ɛ s t r i ə l / , and (via French) terrene / t ə ˈ r iː n / , and from
3159-487: Is that it was formed by accretion from material loosed from Earth after a Mars -sized object with about 10% of Earth's mass, named Theia , collided with Earth. It hit Earth with a glancing blow and some of its mass merged with Earth. Between approximately 4.1 and 3.8 Ga , numerous asteroid impacts during the Late Heavy Bombardment caused significant changes to the greater surface environment of
3276-453: Is the basis for the astronomical unit (AU) and is equal to roughly 8.3 light minutes or 380 times Earth's distance to the Moon . Earth orbits the Sun every 365.2564 mean solar days , or one sidereal year . With an apparent movement of the Sun in Earth's sky at a rate of about 1°/day eastward, 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
3393-457: Is tied to that of the Sun. Over the next 1.1 billion years , solar luminosity will increase by 10%, and over the next 3.5 billion years by 40%. Earth's increasing surface temperature will accelerate the inorganic carbon cycle , possibly reducing CO 2 concentration to levels lethally low for current plants ( 10 ppm for C4 photosynthesis ) in approximately 100–900 million years . A lack of vegetation would result in
3510-410: The constitutive theory a state is a legal entity of international law if, and only if, it is recognised as sovereign by at least one other country. Because of this, new states could not immediately become part of the international community or be bound by international law, and recognised nations did not have to respect international law in their dealings with them. In 1912, L. F. L. Oppenheim said
3627-583: 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 . The axial tilt of Earth is approximately 23.439281° 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
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3744-759: 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 55 Ma . The fastest-moving plates are
3861-562: The Sun and the only astronomical object known to harbor life . This is enabled by Earth being an ocean world , the only one in the Solar System sustaining liquid surface water . Almost all of Earth's water is contained in its global ocean, covering 70.8% of Earth's crust . The remaining 29.2% of Earth's crust is land, most of which is located in the form of continental landmasses within Earth's land hemisphere . Most of Earth's land
3978-627: The United Kingdom , Russia , and the Soviet Union ). These are sometimes referred to as national anthems even though they are not sovereign states (for example, " Hen Wlad Fy Nhadau " is used for Wales, part of the United Kingdom). A positive emotional connection to a country a person belongs to is called patriotism . Patriotism is a sense of love for, devotion to, and sense of attachment to one's country. This attachment can be
4095-606: The World Economic Situation and Prospects Report classifies states as developed countries, economies in transition, or developing countries. The report classifies country development based on per capita gross national income (GNI). The UN identifies subgroups within broad categories based on geographical location or ad hoc criteria. The UN outlines the geographical regions for developing economies like Africa, East Asia, South Asia, Western Asia, Latin America, and
4212-419: The asthenosphere , the solid but less-viscous part of the upper mantle that can flow and move along with the plates. 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
4329-407: The autonomy of media and the degree of support to the media to keep government and officials accountable. The questionnaire takes account of the legal framework for the media (including penalties for press offences, the existence of a state monopoly for certain kinds of media and how the media are regulated) and the level of independence of the public media . It also includes violations of
4446-415: 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. Earth orbits the Sun, making Earth the third-closest planet to the Sun and part of the inner Solar System . Earth's average orbital distance is about 150 million km (93 million mi), which
4563-410: The equatorial region receiving more sunlight than the polar regions) drive atmospheric and ocean currents , producing a global climate system with different climate regions , and a range of weather phenomena such as precipitation , allowing components such as nitrogen to cycle . Earth is rounded into an ellipsoid with a circumference of about 40,000 km. It is the densest planet in
4680-408: The ocean floor form the top of Earth's crust , which together with parts of the upper mantle form Earth's lithosphere . Earth's crust may be divided into oceanic and continental crust. Beneath the ocean-floor sediments, the oceanic crust is predominantly basaltic , while the continental crust may include lower density materials such as granite , sediments and metamorphic rocks. Nearly 75% of
4797-624: The overseas territories of New Zealand , the dependencies of Norway , the British Overseas Territories and Crown Dependencies , the territories of the United States , the external territories of Australia , the special administrative regions of China , the autonomous regions of the Danish Realm, Åland , Overseas France , and the Caribbean Netherlands . Some dependent territories are treated as
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4914-430: The precessing or moving mean March equinox (when the Sun is at 90° on the equator), is 86,164.0905 seconds of mean solar time (UT1) (23 56 4.0905 ) . Thus the sidereal day is shorter than the stellar day by about 8.4 ms. 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
5031-474: The sphere of gravitational influence , of Earth is about 1.5 million km (930,000 mi) in radius. This is the maximum distance at which Earth's gravitational influence is stronger than that of the more distant Sun and planets. Objects must orbit Earth within this radius, or they can become unbound by the gravitational perturbation of the Sun. Earth, along with the Solar System, is situated in
5148-464: The "last ice age", covered large parts of the continents, to the middle latitudes, in ice and ended about 11,700 years ago. 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 current life arose. The evolution of photosynthesis allowed the Sun's energy to be harvested directly by life forms. The resultant molecular oxygen ( O 2 ) accumulated in
5265-541: The 19th century, national flags came to represent most of the states of Europe. Flags also began fostering a sense of unity between different peoples, such as the Union Jack representing a union between England and Scotland , or began to represent unity between nations in a perceived shared struggle, for example, the Pan-Slavic colors or later Pan-Arab colors . As Europeans colonized significant portions of
5382-668: The 19th century, some national anthems predate this period, often existing as patriotic songs long before designation as national anthem. Several countries remain without an official national anthem. In these cases, there are established de facto anthems played at sporting events or diplomatic receptions. These include the United Kingdom (" God Save the King ") and Sweden ( Du gamla, Du fria ). Some sovereign states that are made up of multiple countries or constituencies have associated musical compositions for each of them (such as with
5499-592: The 2020 fiscal year, the World Bank defines low-income economies as countries with a GNI per capita of $ 1,025 or less in 2018; lower-middle-income economies as countries with a GNI per capita between $ 1,026 and $ 3,995; upper-middle-income economies as countries with a GNI per capita between $ 3,996 and $ 12,375; high-income economies as countries with a GNI per capita of $ 12,376 or more.. It also identifies regional trends. The World Bank defines its regions as East Asia and Pacific, Europe and Central Asia, Latin America and
5616-484: The Cambrian explosion, 535 Ma , there have been at least five major mass extinctions and many minor ones. Apart from the proposed current Holocene extinction event, the most recent was 66 Ma , when an asteroid impact triggered the extinction of non-avian dinosaurs and other large reptiles, but largely spared small animals such as insects, mammals , lizards and birds. Mammalian life has diversified over
5733-468: The Caribbean, Middle East and North Africa, North America, South Asia, and Sub-Saharan Africa. Lastly, the World Bank distinguishes countries based on its operational policies. The three categories include International Development Association (IDA) countries, International Bank for Reconstruction and Development (IBRD) countries, and Blend countries. Earth Earth is the third planet from
5850-651: The Caribbean. The 2019 report recognizes only developed countries in North America, Europe, Asia, and the Pacific. The majority of economies in transition and developing countries are found in Africa, Asia, Latin America, and the Caribbean. The World Bank also classifies countries based on GNI per capita. The World Bank Atlas method classifies countries as low-income economies, lower-middle-income economies, upper-middle-income economies, or high-income economies. For
5967-654: The Earth. Terra is also the name of the planet in some Romance languages , languages that evolved from Latin , like Italian and Portuguese , while in other Romance languages the word gave rise to names with slightly altered spellings, like the Spanish Tierra and the French Terre . The Latinate form Gæa or Gaea ( English: / ˈ dʒ iː . ə / ) of the Greek poetic name Gaia ( Γαῖα ; Ancient Greek : [ɡâi̯.a] or [ɡâj.ja] )
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#17327732120756084-555: The English language after the Franco-Norman invasion during the 11th century. In English the word has increasingly become associated with political divisions, so that one sense, associated with the indefinite article – "a country" – is now frequently applied as a synonym for a state or a former sovereign state. It may also be used as a synonym for "nation". Taking as examples Canada , Sri Lanka , and Yugoslavia , cultural anthropologist Clifford Geertz wrote in 1997 that "it
6201-533: The Latin Tellus comes tellurian / t ɛ ˈ l ʊər i ə n / and telluric . The oldest material found in the Solar System is dated to 4.5682 +0.0002 −0.0004 Ga (billion years) ago. By 4.54 ± 0.04 Ga the primordial Earth had formed. The bodies in the Solar System formed and evolved 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
6318-717: The Montevideo Convention merely codified existing legal norms and its principles, and therefore does not apply merely to the signatories of international organizations (such as the United Nations ), but to all subjects of international law as a whole. A similar opinion has been expressed by the European Economic Community , reiterated by the European Union , in the principal statement of its Badinter Committee , and by Judge Challis Professor , James Crawford . According to
6435-426: The Moon and, by inference, to that of Earth. Earth's atmosphere and oceans were formed by volcanic activity and outgassing . Water vapor from these sources condensed into the oceans, augmented by water and ice from asteroids, protoplanets , and comets . Sufficient water to fill the oceans may have been on Earth since it formed. In this model, atmospheric greenhouse gases kept the oceans from freezing when
6552-416: The Solar System . Of the four rocky planets , it is the largest and most massive. Earth is about eight light-minutes away from the Sun and orbits it , taking a year (about 365.25 days) to complete one revolution. Earth rotates around its own axis in slightly less than a day (in about 23 hours and 56 minutes). Earth's axis of rotation is tilted with respect to the perpendicular to its orbital plane around
6669-458: The Solar System's planetary-sized objects, Earth is the object with the highest density . Earth's mass is approximately 5.97 × 10 kg ( 5.970 Yg ). It is composed mostly of iron (32.1% by mass ), 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 gravitational separation ,
6786-623: The Solar System, formed 4.5 billion years ago from gas and dust in the early Solar System . During the first billion years of Earth's history , the ocean formed and then life developed within it. Life spread globally and has been altering Earth's atmosphere and surface, leading to the Great Oxidation Event two billion years ago. Humans emerged 300,000 years ago in Africa and have spread across every continent on Earth. Humans depend on Earth's biosphere and natural resources for their survival, but have increasingly impacted
6903-403: The Sun when the star reaches its maximum radius, otherwise, with tidal effects, it may enter the Sun's atmosphere and be vaporized. Earth has a rounded shape , through hydrostatic equilibrium , with an average diameter of 12,742 kilometres (7,918 mi), making it the fifth largest planetary sized and largest terrestrial object of the Solar System . Due to Earth's rotation it has
7020-465: The Sun, producing seasons . Earth is orbited by one permanent natural satellite , the Moon , which orbits Earth at 384,400 km (1.28 light seconds) and is roughly a quarter as wide as Earth. The Moon's gravity helps stabilize Earth's axis, causes tides and gradually slows Earth's rotation . Tidal locking has made the Moon always face Earth with the same side. Earth, like most other bodies in
7137-481: The WPFI was dramatically changed in 2022. The thresholds for each categorisation have been shifted accordingly. The methodology from 2013 to 2021 used seven general criteria: pluralism (measures the degree of representation of opinions in the media space ), media independence , environment and self-censorship , legislative framework , transparency , infrastructure , and abuses . This category aims to evaluate
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#17327732120757254-425: The atmosphere and due to interaction with ultraviolet solar radiation, formed a protective ozone layer ( O 3 ) in the upper atmosphere. The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes . True multicellular organisms formed as cells within colonies became increasingly specialized. Aided by the absorption of harmful ultraviolet radiation by
7371-426: The atmosphere, particularly carbon dioxide (CO 2 ), creates the conditions for both liquid surface water and water vapor to persist via the capturing of energy from the Sun's light . This process maintains the current average surface temperature of 14.76 °C (58.57 °F), at which water is liquid under normal atmospheric pressure. Differences in the amount of captured energy between geographic regions (as with
7488-450: The center, the temperature may be up to 6,000 °C (10,830 °F), and the pressure could reach 360 GPa (52 million psi ). 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 3 Gyr , twice the present-day heat would have been produced, increasing
7605-454: The continental crust , particularly during the early stages of Earth's history. New continental crust forms as a result of plate tectonics , a process ultimately driven by the continuous loss of heat from Earth's interior. Over the period of hundreds of millions of years, tectonic forces have caused areas of continental crust to group together to form supercontinents that have subsequently broken apart. At approximately 750 Ma , one of
7722-616: The continental surfaces are covered by sedimentary rocks, although they form about 5% of the mass of the crust. Earth's surface topography comprises both the topography of the ocean surface , and the shape of Earth's land surface. The submarine terrain of the ocean floor has an average bathymetric depth of 4 km, and is as varied as the terrain above sea level. Earth's surface is continually being shaped by internal plate tectonic processes including earthquakes and volcanism ; by weathering and erosion driven by ice, water, wind and temperature; and by biological processes including
7839-419: 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. The extent of Earth's magnetic field in space defines the magnetosphere . Ions and electrons of the solar wind are deflected by
7956-527: The core is primarily composed of the denser elements: iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. The most common rock constituents of the crust are oxides . Over 99% of the crust is composed of various oxides of eleven elements, principally oxides containing silicon (the silicate minerals ), aluminium, iron, calcium, magnesium, potassium, or sodium. The major heat-producing isotopes within Earth are potassium-40 , uranium-238 , and thorium-232 . At
8073-463: 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 T , with a magnetic dipole moment of 7.79 × 10 Am at epoch 2000, decreasing nearly 6% per century (although it still remains stronger than its long time average). The convection movements in
8190-419: The country's form of government. The short name is the country's common name by which it is typically identified. The International Organization for Standardization maintains a list of country codes as part of ISO 3166 to designate each country with a two-letter country code . The name of a country can hold cultural and diplomatic significance. Upper Volta changed its name to Burkina Faso to reflect
8307-539: The days shorter. Above the Arctic Circle and below the Antarctic Circle there is no daylight at all for part of the year, causing a polar night , and this night extends for several months at the poles themselves. These same latitudes also experience a midnight sun , where the sun remains visible all day. By astronomical convention, the four seasons can be determined by the solstices—the points in
8424-441: The destructive solar winds and cosmic radiation . Earth has a dynamic atmosphere , which sustains Earth's surface conditions and protects it from most meteoroids and UV-light at entry . It has a composition of primarily nitrogen and oxygen . Water vapor is widely present in the atmosphere, forming clouds that cover most of the planet. The water vapor acts as a greenhouse gas and, together with other greenhouse gases in
8541-611: The earliest known supercontinents, Rodinia , began to break apart. The continents later recombined to form Pannotia at 600–540 Ma , then finally Pangaea , which also began to break apart at 180 Ma . The most recent pattern of ice ages began about 40 Ma , and then intensified during the Pleistocene about 3 Ma . High- and middle-latitude regions have since undergone repeated cycles of glaciation and thaw, repeating about every 21,000, 41,000 and 100,000 years. The Last Glacial Period , colloquially called
8658-516: The efforts made by authorities to respect this freedom. Reporters Without Borders is careful to note that the WPFI only deals with press freedom and does not measure the quality of journalism in the countries it assesses, nor does it look at human rights violations in general. The WPFI is partly based on a questionnaire The scores are evaluated against five distinct categories: political context , legal framework , economic context , sociocultural context and safety . The methodology for
8775-531: The end of French colonization, and the name of North Macedonia was disputed for years due to a conflict with the similarly named Macedonia region in Greece . The ISO 3166-1 standard currently comprises 249 countries, 193 of which are sovereign states that are members of the United Nations. Originally, flags representing a country would generally be the personal flag of its rulers; however, over time,
8892-544: The equally large area of land under permafrost ) or deserts (33%). The pedosphere is the outermost layer of Earth's land surface and is composed of soil and subject to soil formation processes. Soil is crucial for land to be arable. Earth's total arable land is 10.7% of the land surface, with 1.3% being permanent cropland. Earth has an estimated 16.7 million km (6.4 million sq mi) of cropland and 33.5 million km (12.9 million sq mi) of pastureland. The land surface and
9009-404: The experience of human communities. In English, 'country' is both a nation and a part of a 'land'; 'the country' can be the whole society or its rural area. In the long history of human settlements, this connection between the land from which directly or indirectly we all get our living and the achievements of human society has been deeply known. The unclear definition of "country" in modern English
9126-508: The following, regarding constitutive theory: International Law does not say that a State is not in existence as long as it is not recognised, but it takes no notice of it before its recognition. Through recognition only and exclusively a State becomes an International Person and a subject of International Law. In 1976 the Organisation of African Unity define state recognition as: ..the recognition of an independent and sovereign state
9243-505: The free flow of information on the Internet . This category aims to evaluate economic constraints put on the press by carrying out its mission. This category aims to evaluate the social and cultural constraints put on journalists to self-censor against covering specific issues because it would be in opposition to the predominant culture of a country. This category aims to evaluate journalists' safety in disseminating news without
9360-638: The growth and decomposition of biomass into soil . Earth's mechanically rigid outer layer of Earth's crust and upper mantle , the lithosphere , is divided into tectonic plates . These plates are rigid segments that move relative to each other at one of three boundaries types: at convergent boundaries , two plates come together; at divergent boundaries , two plates are pulled apart; and at transform boundaries , two plates slide past one another laterally. Along these plate boundaries, earthquakes, volcanic activity , mountain-building , and oceanic trench formation can occur. The tectonic plates ride on top of
9477-404: 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. The gravity of Earth is the acceleration that is imparted to objects due to the distribution of mass within Earth. Near Earth's surface, gravitational acceleration
9594-406: The land surface is taken by the four continental landmasses , which are (in descending order): Africa-Eurasia , America (landmass) , Antarctica , and Australia (landmass) . These landmasses are further broken down and grouped into the continents . The terrain of the land surface varies greatly and consists of mountains, deserts , plains , plateaus , and other landforms . The elevation of
9711-513: The land surface varies from a low point of −418 m (−1,371 ft) at the Dead Sea , to a maximum altitude of 8,848 m (29,029 ft) at the top of Mount Everest . The mean height of land above sea level is about 797 m (2,615 ft). Land can be covered by surface water , snow, ice, artificial structures or vegetation. Most of Earth's land hosts vegetation, but considerable amounts of land are ice sheets (10%, not including
9828-454: The language still would not come. When referring to a specific polity, the term "country" may refer to a sovereign state , states with limited recognition , constituent country , or a dependent territory . A sovereign state is a political entity that has supreme legitimate authority over a part of the world. There is no universal agreement on the number of "countries" in the world since several states have disputed sovereignty status, and
9945-399: The lithosphere, which is divided into independently moving tectonic plates. 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 660 km (250 and 410 mi) below the surface, spanning a transition zone that separates the upper and lower mantle. Beneath
10062-410: The loss of oxygen in the atmosphere, making current animal life impossible. Due to the increased luminosity, Earth's mean temperature may reach 100 °C (212 °F) in 1.5 billion years, and all ocean water will evaporate and be lost to space, which may trigger a runaway greenhouse effect , within an estimated 1.6 to 3 billion years. Even if the Sun were stable, a fraction of the water in
10179-456: The lowercase when it is preceded by "the", such as "the atmosphere of the earth". It almost always appears in lowercase in colloquial expressions such as "what on earth are you doing?" The name Terra / ˈ t ɛr ə / occasionally is used in scientific writing and especially in science fiction to distinguish humanity's inhabited planet from others, while in poetry Tellus / ˈ t ɛ l ə s / has been used to denote personification of
10296-497: The magnetosphere. 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 an aurora . 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 ). Because Earth's solar day
10413-409: The magnetosphere; solar wind pressure compresses the day-side of the magnetosphere, to about 10 Earth radii, and extends the night-side magnetosphere into a long tail. Because the velocity of the solar wind is greater than the speed at which waves propagate through the solar wind, a supersonic bow shock precedes the day-side magnetosphere within the solar wind. Charged particles are contained within
10530-483: The magnetosphere; the plasmasphere is defined by low-energy particles that essentially follow magnetic field lines as Earth rotates. 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, and the Van Allen radiation belts are formed by high-energy particles whose motion is essentially random, but contained in
10647-417: The mantle, an extremely low viscosity liquid outer core lies above a solid inner core . Earth's inner core may be rotating at a slightly higher angular velocity than the remainder of the planet, advancing by 0.1–0.5° per year, although both somewhat higher and much lower rates have also been proposed. The radius of the inner core is about one-fifth of that of Earth. The density increases with depth. Among
10764-612: The mantle. Due to this recycling, most of the ocean floor is less than 100 Ma old. The oldest oceanic crust is located in the Western Pacific and is estimated to be 200 Ma old. By comparison, the oldest dated continental crust is 4,030 Ma , although zircons have been found preserved as clasts within Eoarchean sedimentary rocks that give ages up to 4,400 Ma , indicating that at least some continental crust existed at that time. The seven major plates are
10881-548: The modern oceans will descend to the mantle , due to reduced steam venting from mid-ocean ridges. The Sun will evolve to become a red giant in about 5 billion years . Models predict that the Sun will expand to roughly 1 AU (150 million km; 93 million mi), about 250 times its present radius. 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
10998-399: The mother of Thor . Historically, "Earth" has been written in lowercase. Beginning with the use of Early Middle English , its definite sense as "the globe" was expressed as "the earth". By the era of Early Modern English , capitalization of nouns began to prevail , and the earth was also written the Earth , particularly when referenced along with other heavenly bodies. More recently,
11115-424: The name is sometimes simply given as Earth , by analogy with the names of the other planets , though "earth" and forms with "the earth" remain common. House styles now vary: Oxford spelling recognizes the lowercase form as the more common, with the capitalized form an acceptable variant. Another convention capitalizes "Earth" when appearing as a name, such as a description of the "Earth's atmosphere", but employs
11232-425: The newly forming Sun had only 70% of its current luminosity . By 3.5 Ga , Earth's magnetic field was established, which helped prevent the atmosphere from being stripped away by the solar wind . As the molten outer layer of Earth cooled it formed the first solid crust , which is thought to have been mafic in composition. The first continental crust , which was more felsic in composition, formed by
11349-593: The ocean may have covered Earth completely. The world ocean is commonly divided into the Pacific Ocean, Atlantic Ocean, Indian Ocean, Antarctic or Southern Ocean , and Arctic Ocean, from largest to smallest. The ocean covers Earth's oceanic crust , with the shelf seas covering the shelves of the continental crust to a lesser extent. The oceanic crust forms large oceanic basins with features like abyssal plains , seamounts , submarine volcanoes , oceanic trenches , submarine canyons , oceanic plateaus , and
11466-670: The oceanic plates, with the Cocos Plate advancing at a rate of 75 mm/a (3.0 in/year) and the Pacific Plate moving 52–69 mm/a (2.0–2.7 in/year). At the other extreme, the slowest-moving plate is the South American Plate, progressing at a typical rate of 10.6 mm/a (0.42 in/year). Earth's interior, like that of the other terrestrial planets, is divided into layers by their chemical or physical ( rheological ) properties. The outer layer
11583-599: The orbit of maximum axial tilt toward or away from the Sun—and the equinoxes , when Earth's rotational axis is aligned with its orbital axis. 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
11700-649: The ozone layer, life colonized Earth's surface. Among the earliest fossil evidence for life is microbial mat fossils found in 3.48 billion-year-old sandstone in Western Australia , biogenic graphite found in 3.7 billion-year-old metasedimentary rocks in Western Greenland , and remains of biotic material found in 4.1 billion-year-old rocks in Western Australia. The earliest direct evidence of life on Earth
11817-474: The partial melting of this mafic crust. The presence of grains of the mineral zircon of Hadean age in Eoarchean sedimentary rocks suggests that at least some felsic crust existed as early as 4.4 Ga , only 140 Ma after Earth's formation. There are two main models of how this initial small volume of continental crust evolved to reach its current abundance: (1) a relatively steady growth up to
11934-501: The past 66 Mys , and several million years ago, an African ape species gained the ability to stand upright. This facilitated tool use and encouraged communication that provided the nutrition and stimulation needed for a larger brain, which led to 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 to this day. Earth's expected long-term future
12051-478: The planet's environment . Humanity's current impact on Earth's climate and biosphere is unsustainable , threatening the livelihood of humans and many other forms of life, and causing widespread extinctions . The Modern English word Earth developed, via Middle English , from an Old English noun most often spelled eorðe . It has cognates in every Germanic language , and their ancestral root has been reconstructed as * erþō . In its earliest attestation,
12168-421: The polar Northern and Southern hemispheres; or by longitude into the continental Eastern and Western hemispheres. Most of Earth's surface is ocean water: 70.8% or 361 million km (139 million sq mi). This vast pool of salty water is often called the world ocean , and makes Earth with its dynamic hydrosphere a water world or ocean world . Indeed, in Earth's early history
12285-499: The practice of using personal banners as flags of places was abandoned in favor of flags that had some significance to the nation, often its patron saint. Early examples of these were the maritime republics such as Genoa which could be said to have a national flag as early as the 12th century. However, these were still mostly used in the context of marine identification. Although some flags date back earlier, widespread use of flags outside of military or naval context begins only with
12402-495: The present day, which is supported by the radiometric dating of continental crust globally and (2) an initial rapid growth in the volume of continental crust during the Archean , forming the bulk of the continental crust that now exists, which is supported by isotopic evidence from hafnium in zircons and neodymium in sedimentary rocks. The two models and the data that support them can be reconciled by large-scale recycling of
12519-404: The press as reported by the organization. The questionnaire is sent to Reporters Without Borders's partner organizations: 18 freedom of expression non-governmental organizations located in five continents, its 150 correspondents around the world and journalists, researchers, jurists and human rights activists . Countries are ranked on a scale from 0–100 points. Country A country
12636-493: The rates of mantle convection and plate tectonics, and allowing the production of uncommon igneous rocks such as komatiites that are rarely formed today. The mean heat loss from Earth is 87 mW m , for a global heat loss of 4.42 × 10 W . 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 . More of
12753-561: The rise of the idea of the nation state at the end of the 18th century and particularly are a product of the Age of Revolution . Revolutions such as those in France and America called for people to begin thinking of themselves as citizens as opposed to subjects under a king, and thus necessitated flags that represented the collective citizenry, not just the power and right of a ruling family. With nationalism becoming common across Europe in
12870-415: The risk of bodily harm , psychological or emotional distress or professional harm . Violence against journalists, netizens, and media assistants, including abuses attributable to the state , armed militias , clandestine organizations or pressure groups , are monitored by RSF staff during the year and are also part of the final score. A higher score on the report corresponds to greater freedom of
12987-522: The shape of an ellipsoid , bulging at its Equator ; its diameter is 43 kilometres (27 mi) longer there than at its poles . Earth's shape also has local topographic variations; the largest local variations, like the Mariana Trench (10,925 metres or 35,843 feet below local sea level), shortens Earth's average radius by 0.17% and Mount Everest (8,848 metres or 29,029 feet above local sea level) lengthens it by 0.14%. Since Earth's surface
13104-463: The study of flags, vexillology , at both professional and amateur levels, emerged. After World War II, Western vexillology went through a phase of rapid development, with many research facilities and publications being established. A national anthem is a patriotic musical composition symbolizing and evoking eulogies of the history and traditions of a country or nation. Though the custom of an officially adopted national anthem became popular only in
13221-461: The word eorðe was used to translate the many senses of Latin terra and Greek γῆ gē : the ground, its soil , dry land, the human world, the surface of the world (including the sea), and the globe itself. As with Roman Terra /Tellūs and Greek Gaia , Earth may have been a personified goddess in Germanic paganism : late Norse mythology included Jörð ("Earth"), a giantess often given as
13338-422: The world since several states have disputed sovereignty status, limited recognition and a number of non-sovereign entities are commonly considered countries. The definition and usage of the word "country" are flexible and have changed over time. The Economist wrote in 2010 that "any attempt to find a clear definition of a country soon runs into a thicket of exceptions and anomalies." Areas much smaller than
13455-460: The world, they exported ideas of nationhood and national symbols, including flags, with the adoption of a flag becoming seen as integral to the nation-building process. Political change, social reform, and revolutions combined with a growing sense of nationhood among ordinary people in the 19th and 20th centuries led to the birth of new nations and flags around the globe. With so many flags being created, interest in these designs began to develop and
13572-620: 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 in the Southern Hemisphere when the Tropic of Capricorn faces the Sun. In each instance, winter occurs simultaneously in the opposite hemisphere. During the summer, the day lasts longer, and the Sun climbs higher in the sky. In winter, the climate becomes cooler and
13689-504: Was further commented upon by philosopher Simon Keller: Often, a country is presumed to be identical with a collection of citizens. Sometimes, people say that a country is a project, or an idea, or an ideal. Occasionally, philosophers entertain more metaphysically ambitious pictures, suggesting that a country is an organic entity with its own independent life and character, or that a country is an autonomous agent, just like you or me. Such claims are rarely explained or defended, however, and it
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