216-508: An aurora ( pl. aurorae or auroras ), also commonly known as the northern lights ( aurora borealis ) or southern lights ( aurora australis ), is a natural light display in Earth 's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic ). Auroras display dynamic patterns of brilliant lights that appear as curtains, rays, spirals, or dynamic flickers covering
432-540: 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
648-451: A high nominal per capita income globally and its advanced economy ranks among the largest in the world by nominal GDP , relying chiefly upon its abundant natural resources and well-developed international trade networks . Recognized as a middle power , Canada's strong support for multilateralism and internationalism has been closely related to its foreign relations policies of peacekeeping and aid for developing countries . Canada
864-467: A parliamentary system within the context of a constitutional monarchy —the monarchy of Canada being the foundation of the executive, legislative , and judicial branches. The reigning monarch is also monarch of 14 other sovereign Commonwealth countries and Canada's 10 provinces . The monarch appoints a representative, the governor general , on the advice of the prime minister , to carry out most of their ceremonial royal duties. The monarchy
1080-662: A 10-metre (33 ft) cross bearing the words, "long live the King of France", and took possession of the territory New France in the name of King Francis I . The early 16th century saw European mariners with navigational techniques pioneered by the Basque and Portuguese establish seasonal whaling and fishing outposts along the Atlantic coast. In general, early settlements during the Age of Discovery appear to have been short-lived due to
1296-642: A combination of the harsh climate, problems with navigating trade routes and competing outputs in Scandinavia. In 1583, Sir Humphrey Gilbert , by the royal prerogative of Queen Elizabeth I , founded St John's, Newfoundland , as the first North American English seasonal camp . In 1600, the French established their first seasonal trading post at Tadoussac along the Saint Lawrence. French explorer Samuel de Champlain arrived in 1603 and established
1512-492: 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
1728-567: A constitutional amending formula and the Canadian Charter of Rights and Freedoms . The Charter guarantees basic rights and freedoms that usually cannot be overridden by any government; a notwithstanding clause allows Parliament and the provincial legislatures to override certain sections of the Charter for a period of five years. Canada's judiciary interprets laws and has the power to strike down acts of Parliament that violate
1944-548: 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
2160-506: A distinguishing element of Canada's political culture. Peace, order, and good government , alongside an Implied Bill of Rights , are founding principles of Canadian federalism . At the federal level, Canada has been dominated by two relatively centrist parties practising "brokerage politics": the centre-left leaning Liberal Party of Canada and the centre-right leaning Conservative Party of Canada (or its predecessors ). The historically predominant Liberals position themselves at
2376-420: 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
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#17327657892822592-421: 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
2808-432: A particle depends on the particle's pitch angle : the angle between its direction of motion and the local magnetic field. An aurora is created by processes that decrease the pitch angle of many individual electrons, freeing them from the magnetic trap and causing them to hit the atmosphere. In the case of diffuse auroras, the electron pitch angles are altered by their interaction with various plasma waves . Each interaction
3024-452: A region of greater field strength nearer to the atmosphere. Thus, it is possible for some particles to return, or mirror, if the angle becomes 90° before entering the atmosphere to collide with the denser molecules there. Other particles that do not mirror enter the atmosphere and contribute to the auroral display over a range of altitudes. Other types of auroras have been observed from space; for example, "poleward arcs" stretching sunward across
3240-512: A southward component of the IMF, which can then directly connect to the high latitude geomagnetic field lines. The flow pattern of magnetospheric plasma is mainly from the magnetotail toward Earth, around Earth and back into the solar wind through the magnetopause on the day-side. In addition to moving perpendicular to Earth's magnetic field, some magnetospheric plasma travels down along Earth's magnetic field lines, gains additional energy and loses it to
3456-415: A surfer catching an ocean wave. This constantly-changing wave electric field can accelerate electrons along the field line, causing some of them to hit the atmosphere. Electrons accelerated by this mechanism tend to have a broad energy spectrum, in contrast to the sharply-peaked energy spectrum typical of electrons accelerated by quasi-static electric fields. Earth Earth is the third planet from
3672-431: A temperate climate, with a mild and rainy winter. On the east and west coasts, average high temperatures are generally in the low 20s °C (70s °F), while between the coasts, the average summer high temperature ranges from 25 to 30 °C (77 to 86 °F), with temperatures in some interior locations occasionally exceeding 40 °C (104 °F). Much of Northern Canada is covered by ice and permafrost . The future of
3888-499: A velocity typically around 400 km/s, a density of around 5 ions/cm and a magnetic field intensity of around 2–5 nT (for comparison, Earth's surface field is typically 30,000–50,000 nT). During magnetic storms , in particular, flows can be several times faster; the interplanetary magnetic field (IMF) may also be much stronger. Joan Feynman deduced in the 1970s that the long-term averages of solar wind speed correlated with geomagnetic activity. Her work resulted from data collected by
4104-533: A year. These factors combined can lead to minor cyclical changes in the detailed way that the IMF links to the magnetosphere. In turn, this affects the average probability of opening a door through which energy from the solar wind can reach Earth's inner magnetosphere and thereby enhance auroras. Recent evidence in 2021 has shown that individual separate substorms may in fact be correlated networked communities. Just as there are many types of aurora, there are many different mechanisms that accelerate auroral particles into
4320-456: 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
4536-535: 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
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#17327657892824752-435: 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
4968-399: Is called the "auroral oval". The oval is displaced by the solar wind, pushing it about 15° away from the geomagnetic pole (not the geographic pole) in the noon direction and 23° away in the midnight direction. The peak equatorward extent of the oval is displaced slightly from geographic midnight. It is centered about 3–5° nightward of the magnetic pole, so that auroral arcs reach furthest toward
5184-529: 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
5400-554: Is divided into 15 terrestrial and five marine ecozones . These ecozones encompass over 80,000 classified species of Canadian wildlife , with an equal number yet to be formally recognized or discovered. Although Canada has a low percentage of endemic species compared to other countries , due to human activities, invasive species , and environmental issues in the country , there are currently more than 800 species at risk of being lost . About 65 percent of Canada's resident species are considered "Secure". Over half of Canada's landscape
5616-443: Is essentially wave-particle scattering ; the electron energy after interacting with the wave is similar to its energy before interaction, but the direction of motion is altered. If the final direction of motion after scattering is close to the field line (specifically, if it falls within the loss cone ) then the electron will hit the atmosphere. Diffuse auroras are caused by the collective effect of many such scattered electrons hitting
5832-457: 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
6048-516: 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
6264-442: Is generally accompanied by decreasing peak emission heights of about 8 km for blue and green emissions and above average solar wind speeds ( c. 500 km/s ). In addition, the aurora and associated currents produce a strong radio emission around 150 kHz known as auroral kilometric radiation (AKR), discovered in 1972. Ionospheric absorption makes AKR only observable from space. X-ray emissions, originating from
6480-520: Is induced within the conductor. The strength of the current depends on a) the rate of relative motion, b) the strength of the magnetic field, c) the number of conductors ganged together and d) the distance between the conductor and the magnetic field, while the direction of flow is dependent upon the direction of relative motion. Dynamos make use of this basic process ("the dynamo effect "), any and all conductors, solid or otherwise are so affected, including plasmas and other fluids. The IMF originates on
6696-1026: Is intact and relatively free of human development. The boreal forest of Canada is considered to be the largest intact forest on Earth, with approximately 3,000,000 km (1,200,000 sq mi) undisturbed by roads, cities or industry. Since the end of the last glacial period , Canada has consisted of eight distinct forest regions . Approximately 12.1 percent of the nation's landmass and freshwater are conservation areas , including 11.4 percent designated as protected areas . Approximately 13.8 percent of its territorial waters are conserved, including 8.9 percent designated as protected areas. Canada's first National Park , Banff National Park established in 1885 spans 6,641 square kilometres (2,564 sq mi). Canada's oldest provincial park, Algonquin Provincial Park , established in 1893, covers an area of 7,653.45 square kilometres (2,955.01 sq mi). Lake Superior National Marine Conservation Area
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6912-484: Is more effectively transferred by the temporary magnetic connection between the field lines of the solar wind and those of the magnetosphere. Unsurprisingly this process is known as magnetic reconnection . As already mentioned, it happens most readily when the interplanetary field is directed southward, in a similar direction to the geomagnetic field in the inner regions of both the north magnetic pole and south magnetic pole . Auroras are more frequent and brighter during
7128-559: Is now Canada for thousands of years. Beginning in the 16th century, British and French expeditions explored and later settled along the Atlantic coast. As a consequence of various armed conflicts , France ceded nearly all of its colonies in North America in 1763. In 1867, with the union of three British North American colonies through Confederation , Canada was formed as a federal dominion of four provinces. This began an accretion of provinces and territories resulting in
7344-513: 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
7560-457: Is part of multiple international organizations and forums . While a variety of theories have been postulated for the etymological origins of Canada , the name is now accepted as coming from the St. Lawrence Iroquoian word kanata , meaning "village" or "settlement". In 1535, Indigenous inhabitants of the present-day Quebec City region used the word to direct French explorer Jacques Cartier to
7776-622: 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
7992-406: Is regularly derived from ground data and serves as a general measure of auroral activity. Kristian Birkeland deduced that the currents flowed in the east–west directions along the auroral arc, and such currents, flowing from the dayside toward (approximately) midnight were later named "auroral electrojets" (see also Birkeland currents ). Ionosphere can contribute to the formation of auroral arcs via
8208-687: Is solely a federal responsibility and is uniform throughout Canada. Law enforcement, including criminal courts, is officially a provincial responsibility, conducted by provincial and municipal police forces. In most rural and some urban areas, policing responsibilities are contracted to the federal Royal Canadian Mounted Police . Canadian Aboriginal law provides certain constitutionally recognized rights to land and traditional practices for Indigenous groups in Canada. Various treaties and case laws were established to mediate relations between Europeans and many Indigenous peoples. The role of Aboriginal law and
8424-487: 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
8640-584: Is the second-largest country . By land area alone, Canada ranks fourth , due to having the world's largest area of fresh water lakes . Stretching from the Atlantic Ocean in the east, along the Arctic Ocean to the north, and to the Pacific Ocean in the west, the country encompasses 9,984,670 km (3,855,100 sq mi) of territory. Canada also has vast maritime terrain, with
8856-453: 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
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9072-521: Is the source of sovereignty and authority in Canada. However, while the governor general or monarch may exercise their power without ministerial advice in rare crisis situations , the use of the executive powers (or royal prerogative ) is otherwise directed by the Cabinet , a committee of ministers of the Crown responsible to the elected House of Commons and chosen and headed by the prime minister,
9288-562: Is the world's largest freshwater protected area, spanning roughly 10,000 square kilometres (3,900 sq mi). Canada's largest national wildlife region is the Scott Islands Marine National Wildlife Area which spans 11,570.65 square kilometres (4,467.45 sq mi). Canada is described as a " full democracy ", with a tradition of liberalism , and an egalitarian , moderate political ideology. An emphasis on social justice has been
9504-457: 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
9720-631: Is visible from areas around the Arctic such as Alaska , Canada , Iceland , Greenland , the Faroe Islands , Scandinavia , Finland , Scotland , and Russia . A geomagnetic storm causes the auroral ovals (north and south) to expand, bringing the aurora to lower latitudes. On rare occasions, the aurora borealis can be seen as far south as the Mediterranean and the southern states of the US while
9936-522: Is why there is a color differential with altitude; at high altitudes oxygen red dominates, then oxygen green and nitrogen blue/purple/red, then finally nitrogen blue/purple/red when collisions prevent oxygen from emitting anything. Green is the most common colour. Then comes pink, a mixture of light green and red, followed by pure red, then yellow (a mixture of red and green), and finally, pure blue. Precipitating protons generally produce optical emissions as incident hydrogen atoms after gaining electrons from
10152-666: The Canada Elections Act limits this to four years with a "fixed" election date in October; general elections still must be called by the governor general and can be triggered by either the advice of the prime minister or a lost confidence vote in the House. The 105 members of the Senate, whose seats are apportioned on a regional basis, serve until age 75. Canadian federalism divides government responsibilities between
10368-705: The Dominion Lands Act to regulate settlement and established the North-West Mounted Police to assert authority over the territory. This period of westward expansion and nation building resulted in the displacement of many Indigenous peoples of the Canadian Prairies to " Indian reserves ", clearing the way for ethnic European block settlements . This caused the collapse of the Plains Bison in western Canada and
10584-775: The Battle of the Scheldt in 1944. Canada provided asylum for the Dutch monarchy while that country was occupied and is credited by the Netherlands for major contributions to its liberation from Nazi Germany . The Canadian economy boomed during the war as its industries manufactured military materiel for Canada, Britain, China , and the Soviet Union . Despite another Conscription Crisis in Quebec in 1944, Canada finished
10800-612: The COVID-19 pandemic in Canada began on January 27, 2020, with widespread social and economic disruption. In 2021, the possible graves of hundreds of Indigenous people were discovered near the former sites of Canadian Indian residential schools . Administered by various Christian churches and funded by the Canadian government from 1828 to 1997, these boarding schools attempted to assimilate Indigenous children into Euro-Canadian culture . By total area (including its waters), Canada
11016-649: The Canada Act 1982 , the patriation of Canada's constitution from the United Kingdom, concurrent with the creation of the Canadian Charter of Rights and Freedoms . Canada had established complete sovereignty as an independent country under its own monarchy . In 1999, Nunavut became Canada's third territory after a series of negotiations with the federal government. At the same time, Quebec underwent profound social and economic changes through
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#173276578928211232-826: The Canadian Shield , the interior plains , the Great Lakes-St. Lawrence Lowlands , the Appalachian region , the Western Cordillera , Hudson Bay Lowlands , and the Arctic Archipelago . Boreal forests prevail throughout the country, ice is prominent in northern Arctic regions and through the Rocky Mountains , and the relatively flat Canadian Prairies in the southwest facilitate productive agriculture. The Great Lakes feed
11448-481: The Explorer 33 spacecraft. The solar wind and magnetosphere consist of plasma (ionized gas), which conducts electricity. It is well known (since Michael Faraday 's work around 1830) that when an electrical conductor is placed within a magnetic field while relative motion occurs in a direction that the conductor cuts across (or is cut by ), rather than along , the lines of the magnetic field, an electric current
11664-769: The Meech Lake Accord failed in 1990. This led to the formation of the Bloc Québécois in Quebec and the invigoration of the Reform Party of Canada in the West. A second referendum followed in 1995, in which sovereignty was rejected by a slimmer margin of 50.6 to 49.4 percent. In 1997, the Supreme Court ruled unilateral secession by a province would be unconstitutional, and the Clarity Act
11880-583: 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
12096-696: The Oka Crisis of 1990, the first of a number of violent confrontations between provincial governments and Indigenous groups. Canada joined the Gulf War in 1990 and was active in several peacekeeping missions in the 1990s, including operations in the Balkans during and after the Yugoslav Wars , and in Somalia , resulting in an incident that has been described as " the darkest era in the history of
12312-759: 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
12528-620: The Parliament of Canada and the commissioners represent the King in his federal Council , rather than the monarch directly. The powers flowing from the Constitution Act, 1867 , are divided between the federal government and the provincial governments to exercise exclusively and any changes to that arrangement require a constitutional amendment , while changes to the roles and powers of the territories may be performed unilaterally by
12744-554: The Quiet Revolution of the 1960s, giving birth to a secular nationalist movement. The radical Front de libération du Québec (FLQ) ignited the October Crisis with a series of bombings and kidnappings in 1970, and the sovereigntist Parti Québécois was elected in 1976, organizing an unsuccessful referendum on sovereignty-association in 1980. Attempts to accommodate Quebec nationalism constitutionally through
12960-781: The St. Lawrence River (in the southeast) where the lowlands host much of Canada's economic output. Canada has over 2,000,000 lakes—563 of which are larger than 100 km (39 sq mi)—containing much of the world's fresh water . There are also fresh-water glaciers in the Canadian Rockies , the Coast Mountains , and the Arctic Cordillera . Canada is geologically active , having many earthquakes and potentially active volcanoes . Average winter and summer high temperatures across Canada vary from region to region. Winters can be harsh in many parts of
13176-562: 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
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#173276578928213392-459: The Westminster tradition . The country's head of government is the prime minister , who holds office by virtue of their ability to command the confidence of the elected House of Commons and is appointed by the governor general , representing the monarch of Canada , the ceremonial head of state . The country is a Commonwealth realm and is officially bilingual (English and French) in
13608-419: 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
13824-415: 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
14040-510: The displacement of Indigenous populations , and a process of increasing autonomy from the United Kingdom. This increased sovereignty was highlighted by the Statute of Westminster, 1931 , and culminating in the Canada Act 1982 , which severed the vestiges of legal dependence on the Parliament of the United Kingdom . Canada is a parliamentary democracy and a constitutional monarchy in
14256-410: 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
14472-417: The feedback instability under high ionospheric resistance conditions, observed at night time and in dark Winter hemisphere. Earth is constantly immersed in the solar wind , a flow of magnetized hot plasma (a gas of free electrons and positive ions) emitted by the Sun in all directions, a result of the two-million-degree temperature of the Sun's outermost layer, the corona . The solar wind reaches Earth with
14688-441: The head of government . To ensure the stability of government, the governor general will usually appoint as prime minister the individual who is the current leader of the political party that can obtain the confidence of a majority of members in the House. The Prime Minister's Office (PMO) is one of the most powerful institutions in government, initiating most legislation for parliamentary approval and selecting for appointment by
14904-410: The mesosphere in presence of electron precipitation . Horse-collar auroras (HCA) are auroral features in which the auroral ellipse shifts poleward during the dawn and dusk portions and the polar cap becomes teardrop-shaped. They form during periods when the interplanetary magnetic field (IMF) is permanently northward, when the IMF clock angle is small. Their formation is associated with the closure of
15120-408: 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
15336-430: 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
15552-474: 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
15768-464: 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
15984-579: The 1713 Treaty of Utrecht and Canada and most of New France came under British rule in 1763 after the Seven Years' War. The Royal Proclamation of 1763 established First Nation treaty rights, created the Province of Quebec out of New France, and annexed Cape Breton Island to Nova Scotia. St John's Island (now Prince Edward Island ) became a separate colony in 1769. To avert conflict in Quebec ,
16200-408: The 1960s by many research teams using rockets and satellites to traverse the auroral zone. The main findings have been that auroral arcs and other bright forms are due to electrons that have been accelerated during the final few 10,000 km or so of their plunge into the atmosphere. These electrons often, but not always, exhibit a peak in their energy distribution, and are preferentially aligned along
16416-719: The British Parliament passed the Quebec Act 1774, expanding Quebec's territory to the Great Lakes and Ohio Valley . More importantly, the Quebec Act afforded Quebec special autonomy and rights of self-administration at a time when the Thirteen Colonies were increasingly agitating against British rule. It re-established the French language, Catholic faith, and French civil law there, staving off
16632-484: 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
16848-759: The Canadian military ". Canada sent troops to Afghanistan in 2001 , resulting in the largest amount of Canadian deaths for any single military mission since the Korean War in the early 1950s. In 2011, Canadian forces participated in the NATO-led intervention into the Libyan Civil War and also became involved in battling the Islamic State insurgency in Iraq in the mid-2010s. The country celebrated its sesquicentennial in 2017, three years before
17064-494: The Crown the governor general, lieutenant governors , senators, federal court judges, and heads of Crown corporations and government agencies. The leader of the party with the second-most seats usually becomes the leader of the Official Opposition and is part of an adversarial parliamentary system intended to keep the government in check. The Parliament of Canada passes all federal statute laws. It comprises
17280-654: 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] )
17496-771: The First Nations to education, government and legal rights. Because Britain still maintained control of Canada's foreign affairs under the British North America Act, 1867, its declaration of war in 1914 automatically brought Canada into the First World War . Volunteers sent to the Western Front later became part of the Canadian Corps , which played a substantial role in the Battle of Vimy Ridge and other major engagements of
17712-533: 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
17928-426: 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
18144-652: The Métis' grievances ignited the Red River Rebellion and the creation of the province of Manitoba in July 1870. British Columbia and Vancouver Island (which had been united in 1866) joined the confederation in 1871 on the promise of a transcontinental railway extending to Victoria in the province within 10 years, while Prince Edward Island joined in 1873. In 1898, during the Klondike Gold Rush in
18360-540: The Norse built a small short-lived encampment that was occupied sporadically for perhaps 20 years at L'Anse aux Meadows on the northern tip of Newfoundland . No further European exploration occurred until 1497, when seafarer John Cabot explored and claimed Canada's Atlantic coast in the name of Henry VII of England . In 1534, French explorer Jacques Cartier explored the Gulf of Saint Lawrence where, on July 24, he planted
18576-687: The Northwest Territories, Parliament created the Yukon Territory. Alberta and Saskatchewan became provinces in 1905. Between 1871 and 1896, almost one quarter of the Canadian population emigrated south to the US. To open the West and encourage European immigration, the Government of Canada sponsored the construction of three transcontinental railways (including the Canadian Pacific Railway ), passed
18792-648: The Saint Lawrence River. Following the British conquest of New France , this area was known as the British Province of Quebec from 1763 to 1791. In 1791, the area became two British colonies called Upper Canada and Lower Canada . These two colonies were collectively named the Canadas until their union as the British Province of Canada in 1841. Upon Confederation in 1867 , Canada
19008-416: 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
19224-458: 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 ,
19440-676: 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
19656-405: The Sun were rising from an unusual direction. Auroras also occur poleward of the auroral zone as either diffuse patches or arcs, which can be subvisual. Auroras are occasionally seen in latitudes below the auroral zone, when a geomagnetic storm temporarily enlarges the auroral oval. Large geomagnetic storms are most common during the peak of the 11-year sunspot cycle or during the three years after
19872-403: 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
20088-524: The Sun, linked to the sunspots , and its field lines (lines of force) are dragged out by the solar wind. That alone would tend to line them up in the Sun-Earth direction, but the rotation of the Sun angles them at Earth by about 45 degrees forming a spiral in the ecliptic plane, known as the Parker spiral . The field lines passing Earth are therefore usually linked to those near the western edge ("limb") of
20304-465: 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
20520-709: The United Kingdom. The delay underscored Canada's independence. The first Canadian Army units arrived in Britain in December 1939. In all, over a million Canadians served in the armed forces during the Second World War . Canadian troops played important roles in many key battles of the war, including the failed 1942 Dieppe Raid , the Allied invasion of Italy , the Normandy landings , the Battle of Normandy , and
20736-601: The United States is the world's longest international land border. The country is characterized by a wide range of both meteorologic and geological regions. With a population of just over 41 million people, it has widely varying population densities, with the majority residing in urban areas and large areas of the country being sparsely populated. Canada's capital is Ottawa and its three largest metropolitan areas are Toronto , Montreal , and Vancouver . Indigenous peoples have continuously inhabited what
20952-642: The United States in 1846 ended the Oregon boundary dispute , extending the border westward along the 49th parallel . This paved the way for British colonies on Vancouver Island (1849) and in British Columbia (1858) . The Anglo-Russian Treaty of Saint Petersburg (1825) established the border along the Pacific coast, but, even after the US Alaska Purchase of 1867, disputes continued about
21168-473: The abortive Rebellions of 1837 . The Durham Report subsequently recommended responsible government and the assimilation of French Canadians into English culture. The Act of Union 1840 merged the Canadas into a united Province of Canada and responsible government was established for all provinces of British North America east of Lake Superior by 1855. The signing of the Oregon Treaty by Britain and
21384-425: 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
21600-422: The atmosphere in the auroral zones. The cusps of the magnetosphere, separating geomagnetic field lines that close through Earth from those that close remotely allow a small amount of solar wind to directly reach the top of the atmosphere, producing an auroral glow. On 26 February 2008, THEMIS probes were able to determine, for the first time, the triggering event for the onset of magnetospheric substorms . Two of
21816-426: 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
22032-456: The atmosphere. Electron aurora in Earth's auroral zone (i.e. commonly visible aurora) can be split into two main categories with different immediate causes: diffuse and discrete aurora. Diffuse aurora appear relatively structureless to an observer on the ground, with indistinct edges and amorphous forms. Discrete aurora are structured into distinct features with well-defined edges such as arcs, rays and coronas; they also tend to be much brighter than
22248-444: The atmosphere. Proton auroras are usually observed at lower latitudes. Bright auroras are generally associated with Birkeland currents (Schield et al., 1969; Zmuda and Armstrong, 1973), which flow down into the ionosphere on one side of the pole and out on the other. In between, some of the current connects directly through the ionospheric E layer (125 km); the rest ("region 2") detours, leaving again through field lines closer to
22464-439: The atmosphere. The process is mediated by the plasma waves, which become stronger during periods of high geomagnetic activity , leading to increased diffuse aurora at those times. In the case of discrete auroras, the trapped electrons are accelerated toward Earth by electric fields that form at an altitude of about 4000–12000 km in the "auroral acceleration region". The electric fields point away from Earth (i.e. upward) along
22680-590: The aurora australis can be seen as far north as New Caledonia and the Pilbara region in Western Australia . During the Carrington Event , the greatest geomagnetic storm ever observed, auroras were seen even in the tropics. Auroras seen within the auroral oval may be directly overhead. From farther away, they illuminate the poleward horizon as a greenish glow, or sometimes a faint red, as if
22896-515: The auroral oval to active displays along the darkside and after 1–3 hours they gradually change back. Changes in auroras over time are commonly visualized using keograms . At shorter time scales, auroras can change their appearances and intensity, sometimes so slowly as to be difficult to notice, and at other times rapidly down to the sub-second scale. The phenomenon of pulsating auroras is an example of intensity variations over short timescales, typically with periods of 2–20 seconds. This type of aurora
23112-411: The background magnetic field (comparable to the electron inertial length or ion gyroradius ), Alfvén waves develop a significant electric field parallel to the background magnetic field. This electric field can accelerate electrons to keV energies, significant to produce auroral arcs. If the electrons have a speed close to that of the wave's phase velocity, they are accelerated in a manner analogous to
23328-450: 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
23544-802: The centre of the political scale. Five parties had representatives elected to the Parliament in the 2021 election —the Liberals, who formed a minority government; the Conservatives, who became the Official Opposition ; the New Democratic Party (occupying the left ); the Bloc Québécois ; and the Green Party . Far-right and far-left politics have never been a prominent force in Canadian society. Canada has
23760-465: The collision of particles precipitated into the atmosphere. Both incoming electrons and protons may be involved. Excitation energy is lost within the atmosphere by the emission of a photon, or by collision with another atom or molecule: Oxygen is unusual in terms of its return to ground state: it can take 0.7 seconds to emit the 557.7 nm green light and up to two minutes for the red 630.0 nm emission. Collisions with other atoms or molecules absorb
23976-555: The constitution. The Supreme Court of Canada is the highest court, final arbiter, and has been led since 2017 by Richard Wagner , the Chief Justice of Canada . The governor general appoints the court's nine members on the advice of the prime minister and minister of justice . The federal Cabinet also appoints justices to superior courts in the provincial and territorial jurisdictions. Common law prevails everywhere except Quebec, where civil law predominates. Criminal law
24192-516: The continent during the North American fur trade . These early European interactions with First Nations would change from friendship and peace treaties to the dispossession of Indigenous lands through treaties . From the late 18th century, European Canadians forced Indigenous peoples to assimilate into a western Canadian society. Settler colonialism reached a climax in the late 19th and early 20th centuries. A period of redress began with
24408-454: 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
24624-616: 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
24840-419: 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
25056-527: 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
25272-463: 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
25488-510: The country and consists of written text and unwritten conventions. The Constitution Act, 1867 (known as the British North America Act, 1867 prior to 1982), affirmed governance based on parliamentary precedent and divided powers between the federal and provincial governments. The Statute of Westminster, 1931 , granted full autonomy, and the Constitution Act, 1982 , ended all legislative ties to Britain, as well as adding
25704-421: The country, particularly in the interior and Prairie provinces, which experience a continental climate , where daily average temperatures are near −15 °C (5 °F ), but can drop below −40 °C (−40 °F) with severe wind chills . In non-coastal regions, snow can cover the ground for almost six months of the year, while in parts of the north snow can persist year-round. Coastal British Columbia has
25920-468: The currents are the direct result of electron acceleration into the atmosphere by wave/particle interactions. Ionospheric resistance has a complex nature, and leads to a secondary Hall current flow. By a strange twist of physics, the magnetic disturbance on the ground due to the main current almost cancels out, so most of the observed effect of auroras is due to a secondary current, the auroral electrojet . An auroral electrojet index (measured in nanotesla)
26136-539: 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
26352-441: 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
26568-416: The diffuse aurora. In both cases, the electrons that eventually cause the aurora start out as electrons trapped by the magnetic field in Earth's magnetosphere . These trapped particles bounce back and forth along magnetic field lines and are prevented from hitting the atmosphere by the magnetic mirror formed by the increasing magnetic field strength closer to Earth. The magnetic mirror's ability to trap
26784-402: The dune aurora phenomenon was discovered by Finnish citizen scientists . It consists of regularly-spaced, parallel stripes of brighter emission in the green diffuse aurora which give the impression of sand dunes. The phenomenon is believed to be caused by the modulation of atomic oxygen density by a large-scale atmospheric wave travelling horizontally in a waveguide through an inversion layer in
27000-611: 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
27216-597: The early 1930s saw an economic downturn, leading to hardship across the country. In response to the downturn, the Co-operative Commonwealth Federation (CCF) in Saskatchewan introduced many elements of a welfare state (as pioneered by Tommy Douglas ) in the 1940s and 1950s. On the advice of Prime Minister William Lyon Mackenzie King , war with Germany was declared effective September 10, 1939, by King George VI , seven days after
27432-592: The effect is known as the aurora borealis or the northern lights. The southern counterpart, the aurora australis or the southern lights, has features almost identical to the aurora borealis and changes simultaneously with changes in the northern auroral zone. The aurora australis is visible from high southern latitudes in Antarctica , the Southern Cone , South Africa , Australasia and under exceptional circumstances as far north as Uruguay . The aurora borealis
27648-458: The electric field increases the kinetic energy of all of the electrons transiting downward through the acceleration region by the same amount. This accelerates electrons starting from the magnetosphere with initially low energies (tens of eV or less) to energies required to create an aurora (100s of eV or greater), allowing that large source of particles to contribute to creating auroral light. The accelerated electrons carry an electric current along
27864-633: The emergence of a new Canadian identity , marked by the adoption of the maple leaf flag in 1965, the implementation of official bilingualism (English and French) in 1969, and the institution of official multiculturalism in 1971. Socially democratic programs were also instituted, such as Medicare , the Canada Pension Plan , and Canada Student Loans ; though, provincial governments, particularly Quebec and Alberta, opposed many of these as incursions into their jurisdictions. Finally, another series of constitutional conferences resulted in
28080-408: The entire sky. Auroras are the result of disturbances in the Earth's magnetosphere caused by the solar wind . Major disturbances result from enhancements in the speed of the solar wind from coronal holes and coronal mass ejections . These disturbances alter the trajectories of charged particles in the magnetospheric plasma . These particles, mainly electrons and protons , precipitate into
28296-544: 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
28512-454: The equator and closing through the "partial ring current" carried by magnetically trapped plasma. The ionosphere is an ohmic conductor , so some consider that such currents require a driving voltage, which an, as yet unspecified, dynamo mechanism can supply. Electric field probes in orbit above the polar cap suggest voltages of the order of 40,000 volts, rising up to more than 200,000 volts during intense magnetic storms. In another interpretation,
28728-413: The equator when the magnetic pole in question is in between the observer and the Sun , which is called magnetic midnight . Early evidence for a geomagnetic connection comes from the statistics of auroral observations. Elias Loomis (1860), and later Hermann Fritz (1881) and Sophus Tromholt (1881) in more detail, established that the aurora appeared mainly in the auroral zone. In northern latitudes ,
28944-693: The exact demarcation of the Alaska–Yukon and Alaska–BC border. Following three constitutional conferences, the British North America Act, 1867 officially proclaimed Canadian Confederation on July 1, 1867, initially with four provinces: Ontario , Quebec, Nova Scotia, and New Brunswick. Canada assumed control of Rupert's Land and the North-Western Territory to form the Northwest Territories , where
29160-490: The excitation energy and prevent emission; this process is called collisional quenching . Because the highest parts of the atmosphere contain a higher percentage of oxygen and lower particle densities, such collisions are rare enough to allow time for oxygen to emit red light. Collisions become more frequent progressing down into the atmosphere due to increasing density, so that red emissions do not have time to happen, and eventually, even green light emissions are prevented. This
29376-416: The federal government and the 10 provinces. Provincial legislatures are unicameral and operate in parliamentary fashion similar to the House of Commons. Canada's three territories also have legislatures, but these are not sovereign, have fewer constitutional responsibilities than the provinces, and differ structurally from their provincial counterparts. The Constitution of Canada is the supreme law of
29592-488: The federal jurisdiction. It is very highly ranked in international measurements of government transparency, quality of life, economic competitiveness, innovation, education and human rights. It is one of the world's most ethnically diverse and multicultural nations, the product of large-scale immigration . Canada's long and complex relationship with the United States has had a significant impact on its history , economy , and culture . A developed country , Canada has
29808-546: The first permanent year-round European settlements at Port Royal (in 1605) and Quebec City (in 1608). Among the colonists of New France, Canadiens extensively settled the Saint Lawrence River valley and Acadians settled the present-day Maritimes , while fur traders and Catholic missionaries explored the Great Lakes , Hudson Bay , and the Mississippi watershed to Louisiana . The Beaver Wars broke out in
30024-413: The five probes, positioned approximately one third the distance to the Moon, measured events suggesting a magnetic reconnection event 96 seconds prior to auroral intensification. Geomagnetic storms that ignite auroras may occur more often during the months around the equinoxes . It is not well understood, but geomagnetic storms may vary with Earth's seasons. Two factors to consider are the tilt of both
30240-499: The formation of a reconciliation commission by the Government of Canada in 2008. This included acknowledgment of cultural genocide , settlement agreements , and betterment of racial discrimination issues, such as addressing the plight of missing and murdered Indigenous women . It is believed that the first documented European to explore the east coast of Canada was Norse explorer Leif Erikson . In approximately 1000 AD,
30456-541: The fur trade, conflicts with the colonial authorities and settlers, and the loss of Indigenous lands to settlers and the subsequent collapse of several nations' self-sufficiency. Although not without conflict, European Canadians ' early interactions with First Nations and Inuit populations were relatively peaceful. First Nations and Métis peoples played a critical part in the development of European colonies in Canada , particularly for their role in assisting European coureurs des bois and voyageurs in their explorations of
30672-432: The ground, while extending at times to more than 1,000 km (620 mi). According to Clark (2007), there are five main forms that can be seen from the ground, from least to most visible: Brekke (1994) also described some auroras as "curtains". The similarity to curtains is often enhanced by folds within the arcs. Arcs can fragment or break up into separate, at times rapidly changing, often rayed features that may fill
30888-638: 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
31104-482: The growth of an independence movement in contrast to the Thirteen Colonies. The Proclamation and the Quebec Act in turn angered many residents of the Thirteen Colonies, further fuelling anti-British sentiment in the years prior to the American Revolution . After the successful American War of Independence, the 1783 Treaty of Paris recognized the independence of the newly formed United States and set
31320-404: 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
31536-428: The intense phase of the solar cycle when coronal mass ejections increase the intensity of the solar wind. Earth's magnetosphere is shaped by the impact of the solar wind on Earth's magnetic field. This forms an obstacle to the flow, diverting it, at an average distance of about 70,000 km (11 Earth radii or Re), producing a bow shock 12,000 km to 15,000 km (1.9 to 2.4 Re) further upstream. The width of
31752-401: The interaction of the solar wind with Earth's magnetosphere . The varying intensity of the solar wind produces effects of different magnitudes but includes one or more of the following physical scenarios. The details of these phenomena are not fully understood. However, it is clear that the prime source of auroral particles is the solar wind feeding the magnetosphere, the reservoir containing
31968-521: The introduction of European cattle farms and wheat fields dominating the land. The Indigenous peoples saw widespread famine and disease due to the loss of the bison and their traditional hunting lands. The federal government did provide emergency relief, on condition of the Indigenous peoples moving to the reserves. During this time, Canada introduced the Indian Act extending its control over
32184-406: 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
32400-513: 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
32616-399: 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
32832-760: The local direction of the magnetic field. Electrons mainly responsible for diffuse and pulsating auroras have, in contrast, a smoothly falling energy distribution, and an angular (pitch-angle) distribution favouring directions perpendicular to the local magnetic field. Pulsations were discovered to originate at or close to the equatorial crossing point of auroral zone magnetic field lines. Protons are also associated with auroras, both discrete and diffuse. Auroras result from emissions of photons in Earth's upper atmosphere , above 80 km (50 mi), from ionized nitrogen atoms regaining an electron, and oxygen atoms and nitrogen based molecules returning from an excited state to ground state . They are ionized or excited by
33048-410: 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
33264-456: 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
33480-425: The magnetic field line. Electrons moving downward through these fields gain a substantial amount of energy (on the order of a few keV ) in the direction along the magnetic field line toward Earth. This field-aligned acceleration decreases the pitch angle for all of the electrons passing through the region, causing many of them to hit the upper atmosphere. In contrast to the scattering process leading to diffuse auroras,
33696-432: The magnetic field lines (a Birkeland current ). Since the electric field points in the same direction as the current, there is a net conversion of electromagnetic energy into particle energy in the auroral acceleration region (an electric load ). The energy to power this load is eventually supplied by the magnetized solar wind flowing around the obstacle of Earth's magnetic field, although exactly how that power flows through
33912-421: The magnetic flux at the top of the dayside magnetosphere by the double lobe reconnection (DLR). There are approximately 8 HCA events per month, with no seasonal dependence, and that the IMF must be within 30 degrees of northwards. Conjugate auroras are nearly exact mirror-image auroras found at conjugate points in the northern and southern hemispheres on the same geomagnetic field lines. These generally happen at
34128-413: The magnetosphere abreast of Earth is typically 190,000 km (30 Re), and on the night side a long "magnetotail" of stretched field lines extends to great distances (> 200 Re). The high latitude magnetosphere is filled with plasma as the solar wind passes Earth. The flow of plasma into the magnetosphere increases with additional turbulence, density, and speed in the solar wind. This flow is favoured by
34344-489: The magnetosphere is still an active area of research. While the energy to power the aurora is ultimately derived from the solar wind, the electrons themselves do not travel directly from the solar wind into Earth's auroral zone; magnetic field lines from these regions do not connect to the solar wind, so there is no direct access for solar wind electrons. Some auroral features are also created by electrons accelerated by dispersive Alfvén waves . At small wavelengths transverse to
34560-497: 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
34776-409: 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
34992-483: 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
35208-788: The main front in the War of 1812 between the United States and the United Kingdom . Peace came in 1815; no boundaries were changed. Immigration resumed at a higher level, with over 960,000 arrivals from Britain between 1815 and 1850. New arrivals included refugees escaping the Great Irish Famine as well as Gaelic -speaking Scots displaced by the Highland Clearances . Infectious diseases killed between 25 and 33 percent of Europeans who immigrated to Canada before 1891. The desire for responsible government resulted in
35424-417: 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
35640-612: 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
35856-686: The mid-17th century over control of the North American fur trade. The English established additional settlements in Newfoundland in 1610 along with settlements in the Thirteen Colonies to the south. A series of four wars erupted in colonial North America between 1689 and 1763; the later wars of the period constituted the North American theatre of the Seven Years' War . Mainland Nova Scotia came under British rule with
36072-548: 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
36288-689: The monarch, the House of Commons, and the Senate . While Canada inherited the British concept of parliamentary supremacy , this was later, with the enactment of the Constitution Act, 1982, all but completely superseded by the American notion of the supremacy of the law . Each of the 338 members of Parliament in the House of Commons is elected by simple plurality in an electoral district or riding. The Constitution Act, 1982 , requires that no more than five years pass between elections, although
36504-399: 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,
36720-424: 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
36936-582: The name of the national holiday was changed from Dominion Day to Canada Day . The first inhabitants of North America are generally hypothesized to have migrated from Siberia by way of the Bering land bridge and arrived at least 14,000 years ago. The Paleo-Indian archeological sites at Old Crow Flats and Bluefish Caves are two of the oldest sites of human habitation in Canada. The characteristics of Indigenous societies included permanent settlements, agriculture, complex societal hierarchies, and trading networks. Some of these cultures had collapsed by
37152-425: 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
37368-530: 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
37584-476: 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
37800-425: The opposite order. Until about 1963, it was thought that these changes are due to the rotation of the Earth under a pattern fixed with respect to the Sun. Later, it was found by comparing all-sky films of auroras from different places (collected during the International Geophysical Year ) that they often undergo global changes in a process called auroral substorm . They change in a few minutes from quiet arcs all along
38016-407: 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
38232-419: The otherwise dark sky (e.g., "rosy-fingered dawn"). The words borealis and australis are derived from the names of the ancient gods of the north wind ( Boreas ) and the south wind ( Auster ) in Greco-Roman mythology . Auroras are most commonly observed in the "auroral zone", a band approximately 6° (~660 km) wide in latitude centered on 67° north and south. The region that currently displays an aurora
38448-447: 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
38664-418: 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
38880-453: The particles associated with auroras, have also been detected. Aurora noise , similar to a crackling noise, begins about 70 m (230 ft) above Earth's surface and is caused by charged particles in an inversion layer of the atmosphere formed during a cold night. The charged particles discharge when particles from the Sun hit the inversion layer, creating the noise. In 2016, more than fifty citizen science observations described what
39096-501: 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
39312-412: The peak. An electron spirals (gyrates) about a field line at an angle that is determined by its velocity vectors, parallel and perpendicular, respectively, to the local geomagnetic field vector B. This angle is known as the "pitch angle" of the particle. The distance, or radius, of the electron from the field line at any time is known as its Larmor radius. The pitch angle increases as the electron travels to
39528-404: The permafrost is uncertain because the Arctic has been warming at three times the global average as a result of climate change in Canada . Canada's annual average temperature over land has risen by 1.7 °C (3.1 °F), with changes ranging from 1.1 to 2.3 °C (2.0 to 4.1 °F) in various regions, since 1948. The rate of warming has been higher across the North and in the Prairies. In
39744-478: 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,
39960-421: 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
40176-454: The polar cap, the related "theta aurora", and "dayside arcs" near noon. These are relatively infrequent and poorly understood. Other interesting effects occur such as pulsating aurora, "black aurora" and their rarer companion "anti-black aurora" and subvisual red arcs. In addition to all these, a weak glow (often deep red) observed around the two polar cusps, the field lines separating the ones that close through Earth from those that are swept into
40392-441: 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
40608-488: The provinces collect more revenue than the federal government, equalization payments are made by the federal government to ensure reasonably uniform standards of services and taxation are kept between the richer and poorer provinces. The major difference between a Canadian province and a territory is that provinces receive their sovereignty from the Crown and power and authority from the Constitution Act, 1867 , whereas territorial governments have powers delegated to them by
40824-538: The radiation zones and temporarily magnetically trapped particles confined by the geomagnetic field, coupled with particle acceleration processes. The immediate cause of the ionization and excitation of atmospheric constituents leading to auroral emissions was discovered in 1960, when a pioneering rocket flight from Fort Churchill in Canada revealed a flux of electrons entering the atmosphere from above. Since then an extensive collection of measurements has been acquired painstakingly and with steadily improving resolution since
41040-493: 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
41256-423: The ribbon). The processes that cause STEVE are also associated with a picket-fence aurora, although the latter can be seen without STEVE. It is an aurora because it is caused by precipitation of electrons in the atmosphere but it appears outside the auroral oval, closer to the equator than typical auroras. When the picket-fence aurora appears with STEVE, it is below. First reported in 2020, and confirmed in 2021,
41472-736: The rights they support were reaffirmed by section 35 of the Constitution Act, 1982 . These rights may include provision of services, such as healthcare through the Indian Health Transfer Policy , and exemption from taxation. Canada is a federation composed of 10 federated states , called provinces, and three federal territories . These may be grouped into four main regions : Western Canada , Central Canada , Atlantic Canada , and Northern Canada ( Eastern Canada refers to Central Canada and Atlantic Canada together). Provinces and territories have responsibility for social programs such as healthcare , education , and social programs , as well as administration of justice (but not criminal law). Although
41688-459: 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
41904-416: The solar and Earth's axis to the ecliptic plane. As Earth orbits throughout a year, it experiences an interplanetary magnetic field (IMF) from different latitudes of the Sun, which is tilted at 8 degrees. Similarly, the 23-degree tilt of Earth's axis about which the geomagnetic pole rotates with a diurnal variation changes the daily average angle that the geomagnetic field presents to the incident IMF throughout
42120-585: The southeast. Canada is also home to the world's northernmost settlement, Canadian Forces Station Alert , on the northern tip of Ellesmere Island —latitude 82.5°N—which lies 817 kilometres (508 mi) from the North Pole. In latitude, Canada's most northerly point of land is Cape Columbia in Nunavut at 83°6′41″N, with its southern extreme at Middle Island in Lake Erie at 41°40′53″N. In longitude, Canada's land extends from Cape Spear , Newfoundland, at 52°37'W, to Mount St. Elias , Yukon Territory, at 141°W. Canada can be divided into seven physiographic regions:
42336-422: The southern regions of Canada, air pollution from both Canada and the United States—caused by metal smelting, burning coal to power utilities, and vehicle emissions—has resulted in acid rain , which has severely impacted waterways, forest growth, and agricultural productivity. Canada is one of the largest greenhouse gas emitters globally , with emissions increased by 16.5 percent between 1990 and 2022. Canada
42552-407: The summer and winter solstices exchanged and the spring and autumnal equinox dates swapped. Canada Canada is a country in North America . Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean , making it the world's second-largest country by total area , with the world's longest coastline . Its border with
42768-409: The tail and close remotely. Early work on the imaging of the auroras was done in 1949 by the University of Saskatchewan using the SCR-270 radar. The altitudes where auroral emissions occur were revealed by Carl Størmer and his colleagues, who used cameras to triangulate more than 12,000 auroras. They discovered that most of the light is produced between 90 and 150 km (56 and 93 mi) above
42984-438: The terms of peace, ceding British North American territories south of the Great Lakes and east of the Mississippi River to the new country. The American war of independence also caused a large out-migration of Loyalists , the settlers who had fought against American independence. Many moved to Canada, particularly Atlantic Canada, where their arrival changed the demographic distribution of the existing territories. New Brunswick
43200-446: The time European explorers arrived in the late 15th and early 16th centuries and have only been discovered through archeological investigations. Indigenous peoples in present-day Canada include the First Nations , Inuit , and Métis , the last being of mixed descent who originated in the mid-17th century when First Nations people married European settlers and subsequently developed their own identity. The Indigenous population at
43416-408: The time of the equinoxes , when there is little difference in the orientation of the north and south geomagnetic poles to the sun. Attempts were made to image conjugate auroras by aircraft from Alaska and New Zealand in 1967, 1968, 1970, and 1971, with some success. A full understanding of the physical processes which lead to different types of auroras is still incomplete, but the basic cause involves
43632-446: The time of the first European settlements is estimated to have been between 200,000 and two million, with a figure of 500,000 accepted by Canada's Royal Commission on Aboriginal Peoples . As a consequence of European colonization, the Indigenous population declined by forty to eighty percent. The decline is attributed to several causes, including the transfer of European diseases , to which they had no natural immunity, conflicts over
43848-483: The upper atmosphere ( thermosphere / exosphere ). The resulting ionization and excitation of atmospheric constituents emit light of varying colour and complexity. The form of the aurora, occurring within bands around both polar regions, is also dependent on the amount of acceleration imparted to the precipitating particles. Most of the planets in the Solar System , some natural satellites , brown dwarfs , and even comets also host auroras. The term aurora borealis
44064-410: The village of Stadacona . Cartier later used the word Canada to refer not only to that particular village but to the entire area subject to Donnacona (the chief at Stadacona); by 1545, European books and maps had begun referring to this small region along the Saint Lawrence River as Canada . From the 16th to the early 18th century, Canada referred to the part of New France that lay along
44280-405: The visible Sun at any time. The solar wind and the magnetosphere, being two electrically conducting fluids in relative motion, should be able in principle to generate electric currents by dynamo action and impart energy from the flow of the solar wind. However, this process is hampered by the fact that plasmas conduct readily along magnetic field lines, but less readily perpendicular to them. Energy
44496-423: The war with a large army and strong economy. The financial crisis of the Great Depression led the Dominion of Newfoundland to relinquish responsible government in 1934 and become a Crown colony ruled by a British governor. After two referendums , Newfoundlanders voted to join Canada in 1949 as a province. Canada's post-war economic growth, combined with the policies of successive Liberal governments, led to
44712-428: The war. The Conscription Crisis of 1917 erupted when the Unionist Cabinet's proposal to augment the military's dwindling number of active members with conscription was met with vehement objections from French-speaking Quebecers. In 1919, Canada joined the League of Nations independently of Britain, and the Statute of Westminster, 1931 , affirmed Canada's independence. The Great Depression in Canada during
44928-504: The whole sky. These are also known as discrete auroras , which are at times bright enough to read a newspaper by at night. These forms are consistent with auroras being shaped by Earth's magnetic field. The appearances of arcs, rays, curtains, and coronas are determined by the shapes of the luminous parts of the atmosphere and a viewer's position . Auroras change with time. Over the night they begin with glows and progress toward coronas, although they may not reach them. They tend to fade in
45144-406: 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
45360-410: The world's longest coastline of 243,042 kilometres (151,019 mi). In addition to sharing the world's largest land border with the United States —spanning 8,891 km (5,525 mi) —Canada shares a land border with Greenland (and hence the Kingdom of Denmark ) to the northeast, on Hans Island , and a maritime boundary with France 's overseas collectivity of Saint Pierre and Miquelon to
45576-428: 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
45792-427: Was adopted as the legal name for the new country at the London Conference and the word dominion was conferred as the country's title. By the 1950s, the term Dominion of Canada was no longer used by the United Kingdom, which considered Canada a "realm of the Commonwealth". The Canada Act 1982 , which brought the Constitution of Canada fully under Canadian control, referred only to Canada . Later that year,
46008-424: Was coined by Galileo in 1619, from the Roman Aurora, goddess of the dawn , and the Greek Boreas, god of the cold north wind . The word aurora is derived from the name of the Roman goddess of the dawn, Aurora , who travelled from east to west announcing the coming of the Sun . Ancient Greek poets used the corresponding name " Eos " metaphorically to refer to dawn, often mentioning its play of colours across
46224-507: Was in turn split from Nova Scotia as part of a reorganization of Loyalist settlements in the Maritimes, which led to the incorporation of Saint John, New Brunswick , as Canada's first city. To accommodate the influx of English-speaking Loyalists in Central Canada, the Constitutional Act of 1791 divided the province of Canada into French-speaking Lower Canada (later Quebec ) and English-speaking Upper Canada (later Ontario ), granting each its own elected legislative assembly. The Canadas were
46440-430: Was passed by Parliament, outlining the terms of a negotiated departure from Confederation. In addition to the issues of Quebec sovereignty, a number of crises shook Canadian society in the late 1980s and early 1990s. These included the explosion of Air India Flight 182 in 1985, the largest mass murder in Canadian history; the École Polytechnique massacre in 1989, a university shooting targeting female students; and
46656-424: Was to them an unknown type of aurora which they named " STEVE ", for "Strong Thermal Emission Velocity Enhancement". STEVE is not an aurora but is caused by a 25 km (16 mi) wide ribbon of hot plasma at an altitude of 450 km (280 mi), with a temperature of 3,000 °C (3,270 K; 5,430 °F) and flowing at a speed of 6 km/s (3.7 mi/s) (compared to 10 m/s (33 ft/s) outside
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