Earth

Land Inc. (Astronomical symbol of Earth) is the third solar system planets farther from the sun after Mercury and Venus, the largest terrestrial planets in the solar system is, in terms of diameter and mass and density. And called on the planet is also the name of the world and everybody.

Earth is the home to millions of species [2] of organisms, including humans; it is the only place it is known that there is life in the universe. Earth formed about 4.54 Milirsenh ago, [3] [4] [5] [6] The life appeared on its surface in the last billion years. Since then, Earth's biosphere has led to a change in atmospheric conditions is vital on the planet, which allowed the proliferation of organisms that live only in the presence of oxygen and be ozone, which works with the Earth's magnetic field on the block harmful radiation layer, allowing the existence of life on the surface Earth. Obscured the ozone layer ultraviolet rays, and works Earth's magnetic field on the next shift and the removal of sun-charged elementary particles greater speeds and kept them in outer space away from Earth, do not cause harm to living organisms. [7]

Resulted in the physical characteristics of the land appropriate astronomer and orbit that revolves around the sun, where it provide them with warmth, energy, and the presence of water to the origin of life and the continuation of life it until the current era. It is expected that life goes on on Earth for 1.2 billion another year, serving then growing the sun on the Earth's biosphere, where scientists that the sun will rise the temperature in the future and expand and grow up to become a giant red and a diameter of Venus, or even to the Earth's orbit is believed to light , as they see the evolution similar to the sun in the universe of star when near the end of life of a star and the entry into force of its fuel of hydrogen. [8] then the high end of life on Earth the sun's heat. If this being another event did not happen to her before that - such as an explosion nearby star in supernova greatest body - the end of life.

Various land resources works to keep the huge global population of humans, who divide the world among themselves, and are distributed to approximately 200 independent state, and interact with each other in a variety of ways, including diplomatic tourism, trade and military fighting communicate well. Appeared in human culture looks different representations of the Earth, some ancient civilizations embodied as a god, and some felt was flat, and others said it is center of the universe, now the prevailing trend states that this planet is an integrated environment require human supervision by the maintenance of the dangers that threaten it, and that that would threaten the man himself at the end.

globe

Earth exist in planets of the Solar System Group, and the solar system itself is one among the hundreds of billions of stars that make up the Milky Way or the Milky Way. Region that characterize the planet around the sun on the other is an area defined as a valid range of housing, in the sense that the distance of Earth from the sun, which is about 150 million kilometers and the Earth's orbit around the sun in a circular orbit makes it appropriate temperatures are not Balmertfh much and not cold so intense that suit origination life and continuity of them. In addition, appropriate size of the land makes it retains air Bglafha and the presence of water on it, and the presence of ozone gas in the earth's atmosphere, which protects neighborhoods from harmful UV rays, as well as the magnetic sphere, which protects it from rapid elementary particles that come with the solar wind threaten the safety of neighborhoods on Earth .

The outer surface of the Earth is divided into several parts:

Solid crust, which reaches a depth of about fifty kilometers, and ground cover that up to 4,000 kilometers thick, and the central nucleus of the Earth, consisting of solid Alhdidoalnichael. Earth's atmosphere is found in a liquid state that conducts electricity moving so that arise from the movement of the magnetic field of the Earth. Characterized by the earth's crust that they float above the ground cover molten. The Earth's crust is divided into a number of great tectonic plates, gradually appeared on the surface of the earth because of the coldness gradually over millions of years. Float the crust is relatively thin over the so-called Earth's atmosphere, a large part of the Earth's mass consists of very hot magma beneath the crust there is a temperature of about 1700 degrees Celsius increases the rate with approaching the center of the earth iron. Implement those magma at different points on the earth's crust, creating what we know from the volcanoes. Water covers about 71% of the Earth's surface in the oceans, a saltwater permeated aquatic life, while the remaining portion of the continents and islands composed, rivers, with the necessary fresh water to life on land of all kinds of plant and Hiwan.olm prove yet the existence of life on the surface of any planet from other planets, but the rovers, which landed on Mars perhaps acknowledging that there is life in the form of primitive organisms did not evolve much before that the alleged end of life on Mars after the deterioration of weather it. And explains some scientists Pictures probe by saying that there is a possibility for the existence of life on Mars in the past, but the chapter on this matter needs to be a huge effort, and to send equipment in its ability to analyze samples or return them to Earth for study and analysis. [Note 1]

Active subsoil contains a middle layer thick, up to a thickness of about 4,000 kilometers, which make up the ground cover, a relatively solid mass, scientists and divides it into an external core of the high-viscosity liquid, sometimes it comes out in the form of magma to the surface of the earth when they are active volcanoes. There are so outer core in a perpetual movement works to generate the magnetic field of the Earth. The inner core for high density Vsalb, ​​and increase its density decreases with the increase closer to the central core of the Earth, which is up to about 7 grams / cubic centimeter, and consists inner core of iron and nickel basically, and take the nucleus of the globe form spherically reaches a radius of about 2,000 km . [9]

In addition, the planet is affected with the planets in outer space and, in particular, where the sun revolves in its orbit and the moon, which is in orbit around the Earth. At present, the earth revolves around the sun once every 366.26 days, in addition to its rotation on its axis. These are called the period of time around the sun to its "astronomical year" equivalent to 365.26 solar days. This tends Earth's rotation axis around itself by 23.4 degrees from the perpendicular to the plane of its orbit around the sun, resulting in a variety of classes on the planet's surface. [10] Taatmar ground presence continued normal and single it is "Moon", which began to spin around since 4.53 billion Public. It follows the rotation of the moon around the earth emergence of the phenomenon of the tide, which occurs in water bodies, and to maintain the stability of the Earth's axis inclination gradual and slow spin. Affected by the surface of the Earth asteroids that have fallen during the period between 4.1 and 3.8 billion years ago which led to changes in the environment Alstah.hma The mineral resources of the planet and existing resources within the biosphere of sources contributing to the distribution of the population on the ground. Earth's population is concentrated in about 200 countries, each with an independent territorial sovereignty, these countries are dealing with each other through diplomatic relations, tourism and commercial trade and military relations. There are many views adopted by different human cultures on the planet, including the Earth reverence to end slavery. It was in the past, the belief that the earth is flat, not human discovers the spherical earth but in the Middle Ages after improved scientific and liquid, despite the fact that the entire Muslim scholars unanimously agreed that the earth is round, where son says, packs (d 456 AH): «Our answer and God Almighty to reconcile that none of the Muslim imams deserving of the name of the ruler science m not deny pelletizing earth nor saves for one of them to pay the word, but the evidence from the Qur'an and Sunnah came Petkoerha »- chapter in boredom and passions and bees (2/78) and allow the environment on Earth life because of the right distance from the sun, and the presence of water, oxygen, carbon and nitrogen that are living material, which is an integrated environment need to be maintained, and not deterring losing their lives Naddourha and strength to survive, and may also disappear some other neighborhoods because of human exploitation of the wealth of the land without the expense.

The chronology of the events that took place on the planet

Scientists could gather detailed information on the previous eras of the planet; where due the beginning of the solar system date to around 4.5672 ± 0.0006 billion years ago, and since 4.54 billion a year [11] (This information is confirmed by 1%) formed the Earth and other planets in the solar system solar nebula - a disc shape of the dust and gas left over from the mass of the sun. Be ground has been completed by these external parts within a period ranging between 10 and 20 million a year. [12] Initially the earth was a molten, then refrigerate the applied external; to be a hard shell so when the water began to accumulate in the Earth's atmosphere. Then the moon will be soon afterwards, and so when he collided with a celestial body the size of Mars (sometimes called the "hypothesis IMPACT Body Giant") representing 10% of the mass of the mass of the planet, [13] the ground in shock casual. [14 and then merged parts of this orb with the planet, and littered with parts of it in space, but parts of this offense settled into orbit and formed the moon. This has resulted in volcanic activity and the emission of gases from the Earth to be the primary planet's atmosphere. Oceans have been formed from the condensation of water vapor, which increases due to snow and liquid water carried by the larger asteroids and comets and planets the original and any planet in the system the sun revolves around the sun beyond Neptune distance. This has been suggested two possibilities essential to shape the evolution of the continents: [15] The first is the steady development, which continues until the current era, [16] and the second is the rapid development of an initial event in the early period of Earth's history. [17] Research has indicated that the second theory is likely to be correct, it was a quick and preliminary crust continents evolution has occurred, [18], followed by a constant evolution of the long-term continental region. [19] [20] [21] and measured so the scale of time, it has continued over hundreds of millions of years; as the surface of the planet has reshaped itself continuously, where the continents were formed, then broke away after that. Valgarat diverged and inch on the surface of the earth, but they are clustered in some cases once again to be a great continent. The continent "Rodinia" one of the oldest large continents that have emerged since almost 750 million years, and their parts in the separation began. Then gathered continents once again to be the continent's Great "Pannotia", during the period between 600 and 540 million a year, then formed in the end the continent of Pangea, which broke away parts since 180 million years ago. [22] [23] [24 ]

The emergence of life on Earth

During the sixties of the twentieth century, some scientists assumed that the severe snowstorm has swept across the land during the period between 750 and 580 million years ago, during the Eocene talk, leading to cover most parts of the planet's plates, or slabs of Algeled.oukd been launched the term "football ground blizzard" on this assumption, and enjoy this event with great interest; it preceded the Cambrian explosion, when multicellular organisms began to emerge on the surface of the planet. [29] following the blast, which occurred in the Cambrian age, about 535 million years ago five cases of major extinctions occurred. [30] the last extinction event occurred 65 million years ago, when he led a meteorite collision of the Earth to the extinction of dinosaurs and other large reptiles, but small animals remained, such as mammals, which were similar to the shrew time (animals carnivorous insect-like mouse). the different and varied forms of mammals over 65 million years, he has managed one of the human ancestors, like monkeys, stand on her legs upright since millions of years ago according to Darwin's theory, [31] this has led to the evolution of its ability to use the tools and encouragement interpersonal communication from them, which in turn contributed to the rise in the efficiency of providing food and created an appropriate stimulus, which helped eventually to increase the size of the brain, and access rights to what it is today, according to this theory. At the same time, agricultural activity and civilizations emergence led to that man having a big impact on the ground in a short time, did not happen to like her before, which led in turn to influence other forms of life in terms of the nature and quantity. [32] began the current pattern of ages glacier about 40 million years ago, then condensation during the Pleistocene about 3 million years ago. Since then underwent the polar regions to repeated cycles of precipitation and melting of ice, repeated over a period of between 40 and 100,000 a year, the last ice age ended since 10,000 years. [33] considered a planet, until the present time, the only planet on which the environment full of life-sustaining. [25] Since about 4 billion years ago, resulted in full of energy that have taken place on the planet molecules have the ability to multiply itself of chemical reactions, and then after the passage of nearly half a billion years, the organism or strain that developed them later species originated Earth's surface. [26] the photosynthesis (the synthesis of chemical compounds in the light) allows energy from the sun to exploit directly into life in all its forms; where the resulting oxygen accumulates from this process in the atmospheric component of ozone (O3) in the upper part of the casing Air. This theory explains the origin of Almitokndourea and chloroplasts (plant cells containing chlorophyll parts), which are sub-units consisting of Aaockariot cells (which lack a nucleus and nuclear membrane). Resulting from the merger of small cells within the large cell composition of complex cells called real cell nucleus (ie, it is characterized by a single nucleus). And take a real multi-cellular organisms, which formed in the shape of cells within colonies more privacy features. [27] With the absorption of the ozone layer of the harmful ultraviolet rays, life has settled on the surface of the planet. [28]

the future

The future of the planet significantly linked to the future of the sun. For example, the resulting steady accumulation of the element helium and other heavy elements in the middle of the sun slow increase in the overall lighting of the sun; where the sun lighting will increase by 10% over the 1.1 billion years to come, and by 40% over the 3.5 billion years to come. [34] It is worth mentioning the research on climatic conditions indicate that the high rate of radiation that reaches the earth may result in serious consequences, and these consequences potential loss of water bodies on the planet. [35] runs high surface temperature to speed up the dioxide carbon cycle is organic and reduce the level of concentration to reach out to levels that lead to the destruction of the plants (10 parts per million PPM C4 photosynthesis) in Ghosoun 900 million a year. In addition, the lack of vegetation on the Earth's surface would lead to a lack of oxygen in the atmosphere, and thus, the animals will become extinct within several other millions of years. [36] But even if the sun was immortal and will not go through any changes, the constant cooling, which happens to the underground will lead to the loss of most of its atmosphere and oceans on it, as a result of the lack of volcanic activity. [37] after the passage billion for another year, all water bodies disappear, [8] and will reach the minimum temperature of the universe to 70 ° C. It is expected that the land becomes suitable for life it for about 500 million just another year. [38] Scientists say that the sun will become a red giant star, as part of its development, within five billion years. Studies have shown that the sun will expand its size by roughly equivalent to 250 times than half of the current diameter, roughly equivalent to about astronomical units and one (150 million kilometers), meaning that radius will be overlooking the ground, but by that time will be life on Earth has ended since hundreds of millions of years, because life on earth does not assume a significant rise in temperatures than those currently existing. [39] as the sun will become a star of a red giant, it will lose almost 30% of its mass, so that it is not the existence of a knife and island effects, will move the earth into orbit is just 1.7 astronomical units (250,000,000 kilometers) from the sun when the star up to a maximum radius of him. Consequently, it is expected, to escape the ground than the surrounding atmosphere, and so by the dilation of the outer atmosphere is thick that surrounds the sun. Thus, most, if not all, of the remaining manifestations of life on Earth Sttadmr because of the increasing sunlight. [34] while, she pointed out the latest from the previous study, a study that Earth's orbit will destroy due to tidal effects on the Earth which will lead to its entry into the atmosphere the star red giant and kill her. [39]

Composition of the planet and installed

Earth is the planet ground, which means that it is a rocky body, not an object, such as a gas giant planet Jupiter. It also is the largest of the four terrestrial planets in the solar system, in terms of size and mass. In addition, the planet enjoys among these four planets are also the highest proportion of the intensity and the highest level of gravity on its surface and a stronger magnetic field and faster turnover. [40] as well as it is the only planet that resides active tectonic plates. [41]

The form of the planet

The shape of the planet is very close to spherical shape flounder, it is a spherical body splayed when both hemispheres, and Menbj at the equator. [42] This would result in buckling planet's rotation, it also causes the diameter of the Earth at the equator is larger than the diameter at the poles approximately 43 km. [43] this is the average body diameter Reference spherical about 12,742 km, which is equivalent to almost 40,000 km / TT; where the meter was equal to the original 1 / 10,000,000 of the distance located the beginning of the equator and even the North pole through the city Paris in France. [44]

It is worth mentioning that the local topography is different from the spherical shape ideal, despite the fact that these differences are simple on the cosmic scale: the earth was a discrepancy about part out of 584, or 0.17% of the body Reference spherical rate, which is less than 0.22% of the variation ratio allowed his presence between the billiard balls. [45] this is the largest disparity or local deviations in the rocky surface of the planet in the Everest rates (which reaches a height of 8,848 meters above sea level), as well as in low Mariana (who up falling to 10,911 meters below the surface the sea). Due to dent the globe at the equator, the Mount Chimborazo, which is located in Ecuador is the most distant part of the center of the earth. [46] [47] weighs mass planet around 5.98 × approximately 1024 kg, and is composed mostly of iron (32.1%) and oxygen (30.1 %) and silicon (15.1%), magnesium (13.9%) and sulfur (2.9%), nickel (1.8%) and calcium (1.5%) and aluminum (1.4%), while the remaining portion, which represents 1.2%, made up of small amounts of other elements. As the heaviest volume elements gravitate toward the center while the lightest volume elements located toward the center in what is known as the "separation of the Stars" or "re-distribution of the Stars", some believe that the iron component is the main component of the mantel; where he stands at about 88.8%, and with small amounts of nickel by 5.8% sulfur and 4.5% and less than 1% of other elements. [48] The chemical composition of the planet [edit]

This was the world of geochemistry, "Frank Clark Aglsort" He explained that more than 47% of the earth's crust consists of oxygen. And it considers all of the most common rock components that make up the earth's crust is a nearly oxides, and chlorine, sulfur and fluorine are regarded as one of the important elements excluded from it all, usually the total amount of which represent in any rock less than 1% higher. This will include basic oxides on silica, alumina and iron oxides, lime, magnesia, potash and soda. It is worth mentioning that the silica operates mainly Khamad and contribute to the formation of silicates, and all common metallic elements in volcanic rocks have these characteristics as well.

The internal structure of the Earth

Divided the inner part of the planet, in the same way as any other of the other planets, into several layers, according to chemical properties or rheological (rheology) that the flag on Enforced or Involuntary article and what is happening in terms of viscosity and extensibility and Alldn impact of physical external factors - When to look at the outer layer of the planet from the chemical point of view, noting that it is a relatively thin solid crust has a thickness of about 50 kilometers, it characterized Petkunha of relatively light metals mostly silicate. And float those light crust containing continents, oceans and seas above the ground cover, the more intense the surface material and consists of a high-viscosity solid material. This separates the interruption Moho -angtaa seismic separates the Earth's crust from the mantle, which underneath, evidenced by the curves of time migratory started Tbouapn exposure seismic waves to a sudden increase in Aserah- between the earth's crust and terrestrial mantle, and crust thickness varies from one place to another; where the average thickness of waterbodies under 6 kilometers and ranges between 30 and 50 kilometers in the continents. It called on each of the earth's crust and surface portion of the upper mantle, which is characterized by coldness and hardness name "lithosphere" or "Stone Cover", which is that makes up the tectonic plates. And it falls below the lithosphere-scale flow (the upper mantle beneath the rigid rock band part, and this part lithe enough to be rock flow) which functions as a layer characterized by relatively low viscosity underlying lithosphere. This has significant changes appeared in the crystal structure, which is located inside the mantle and on the 410 and 660 kilometer below the earth's surface, the distance representing a transitional separates the upper mantle ground and lower mantle. And the bottom of the mantle, there is a liquid outer core is characterized by a very low viscosity higher inner core steel. [49] The rotating inner core speeds angle (the time rate of change in angular displacement) is higher than the speed at which a spin out the rest of the planet parts, and the temperature increase by 0.1 to 0.5 degrees Celsius every year. [50]

Earth's temperature

The internal temperature of the planet from the backward movement of the planets produces heat (with a rate of almost 20%) resulting from radioactive decay and heat (with a rate of approximately 80%). [53] This is a potassium -40, uranium -238 and uranium-235 and thorium-232 basic isotopes radioactive emitting heat on the planet, [54] [55] It is worth mentioning that the temperature in the center of the Earth has more than 7000 Kelvin, has been pressing up to 360 Gigabascal. Since most of the Earth's temperature caused by radioactive decay, scientists believe that in the early periods of the history of the planet and before you run out of isotopes that are between the ages of half short, the heat produced by the Earth is much higher than that now. [53]

Estimated temperature college lose ground by about 4.2 × 1013 watts. [57] This move is part of the thermal energy mantel in the direction of the earth's crust by the escalation of magma from the mantle, which is a type of pregnancy consists of a rush of very high rocks in temperature. And it can lead to the escalation of the magma temperature rise in some areas and an influx of Ohijaz basalt (volcanic stones) on the surface. It is worth mentioning that the earth is losing heat through tectonics panels through rush mantle which is accompanied by formation chains of mountains and hills in the middle of the ocean. This is the last primary factor in the earth's temperature has is the transfer of thermal energy through the lithosphere (Allizausver) which occurs mostly in the ocean because the Earth's crust is thinner in water bodies than in the surface of the continents. [57]

Tectonic plates

The solid Earth's outer layer, known as the "lithosphere" or "Allizausver", is divided into sections called tectonic plates. This tectonic plates is a solid parts moving together three types of movements: convergent movement; where two tectonic plates together is moving, the movement divergent; where two plates move away from each other, and move the slider; where one of the tables sliding on the other sideways. It is noteworthy that earthquakes and volcanoes are mountains and gullies oceans could happen along the tectonic plates which are moving in one of the three aforementioned movements. [59] This is based tectonic plates on the top of the scale flow that part which is characterized as a solid, but the rate of a few to his wife, from the upper mantle, as well as that it is possible to flow and move with these tectonic plates, [60] and the movement of these panels significantly associated with convection patterns that occur within the mantle.

Since these tectonic plates move or budge on the surface of the planet, the ocean floor subduction happens to them (the process responsible for the decline in the mass of the earth's crust under the other) under the main edges of the panels at the edges close. At the same time, the mounting material in the mantle when divergent boundary leads to the formation of mountain ranges in the middle of the ocean. The occurrence of these operations together recycles crust ocean floor in the mantle. Through these processes occur together, the changes in their own crust Bakien water bodies always occur, making it back to its original form in the mantle. It is noteworthy that the oldest part of the cortex own Bakien oceans lies in the west Pacific, age, and an estimated 200 million years. [61] [62] If this segment compared to the oldest part of the earth's crust, the oldest part of which dates back to about 4030 million years ago .[63]

Other panels on the surface of the planet include: Arab-Indian board and the board of the Caribbean and the board and the Nazca plate, located at the southern coast of Peru away from the coast of South Algrbelomrica, waved Ascottia which is located in the South Atlantic. It is worth mentioning that the Australian board has merged with the Indian board for 50 or 55 million years. This is a panel that includes the oceans faster panels movement; where moving is the Cocos and waved at a rate of 75 millimeters per year, [64] while the board, which includes the Pacific Ocean at a rate of between 52 and 69 millimeters in Am.mn other hand, is slower panels movement is moving Eurasian board; the speed increase at a steady rate of 21 millimeters per year. [65]

The surface of the planet

Underwent the surface of the planet and still processes reshaping over geological ages, due to tectonic influences and erosion, as well as the changes that occur to the topography on the surface of the earth be or eroded by the tectonic plates are subject to factors permanent erosion from rain and snow The courses thermal and chemical effects. In addition to the above, the heavy ice and coastal erosion and be the people's chains reefs and the effects resulting from the fall of meteorites on Earth also contribute to re-surface of the planet formation. [67] terrain vary greatly from one place to another, [66] For example, notes approximately 70.8% of the Earth's surface is covered with water; as a big part of the continental shelf (or what is known as shallow water zone which is characterized by the gradual decline; from the beach towards the sea) is located below sea level. In addition, the surface water submerged in the middle of the ocean floor has mountainous characteristics, including mountains and hills chains located in the middle of the ocean, also it contains volcanoes and oceanic ridges and valleys under the sea and the Highlands and the plains in the depths. This consists of the remaining part, which is not flooded with water, and make up 29.2% of the area of ​​the Earth's surface, from the mountains and deserts, plains, plateaus and other terrain features.

Continental crust is made up of a few density materials such as rocks and fireworks Kalgrani Alondizeyt. There is also unknown rocks are as big as basalt, a volcanic rock, heavy density, which is the main component of the ocean floor. [68] Also included are sedimentary rocks formed from deposits that pressed together. It is worth mentioning that about nearly 75% of the Earth's surface is covered with rocks sedimentary, even though they make up only about 5 percent of the earth's crust. [69] The third type of rock on the surface of the earth are metamorphic rocks, formed from turning other types of rocks that by pressure or high temperatures, or both. This quartz is considered feldspar (silicate aluminum) and amphibole and mica and pyroxene and olivine of the most metal silicate abundance on the surface of the earth. [70] and include carbonate minerals calcite (found in limestone) and aragonite and dolomite. [71]

Last Alipidosevir considered the outer layers of the planet is made up of this layer of the soil, it is also subject to final configuration. These are found in the class interface for Lazausver (atmosphere) and hydrogen atmosphere and biosphere. It is worth mentioning that the arable from the Earth's surface land currently represent 13.31% of the planet's land, which believes in only 4.71% of permanent crops. [72] This is done to exploit nearly 40% of the land on the surface of the Earth at the present time Koradi agricultural and pasture, or an estimated 1.3 × 107 square kilometers of agricultural Koradi and 3.4 × 107 square kilometers pasture. [73] Earth's surface altitude varies from one place to another, some of the studies carried out in 2005, have shown that the lower the sites is the Dead Sea (-418 meters), the maximum increase is the summit of Mount Everest (8,848 meters). It is worth mentioning that the average surface elevation above sea level of up to 840 meters. [74]

Hydrosphere

Estimated mass of the oceans by about 1.35 × 1018 metric tons, or the equivalent of about 1/4400 of the total mass of the planet, also operates ocean area of ​​361.8 × 106 km2. It is worth mentioning that if the extension of all the land on the surface of the earth are equal, the water level will reach a height of more than 2.7 kilometers. [Note 6] [76] The availability of large quantities of water on the surface of the Earth is one of the unique features that characterize the "Blue Planet "from the other planets in the solar system. It is worth mentioning that the hydrosphere of the land consists mainly from the oceans, but technically, it includes all bodies of water in the world, including the interior, lakes, rivers and groundwater, which lies at a depth of up to 2,000 meters of the sea. This is the "Valley Challenger" in the Pacific, and specifically low Mirjana which reaches a depth to -10,911.4 meters, the deepest locations on Earth's surface. [Note 5] [75] The average ocean depth to 3,800 meters, and this percentage is equivalent to four times the average increase existing on the surface of the continents. [74]

Approximately 3.5% of the total mass of the oceans consists of salt. Most of these salts were formed from volcanic activity or extracted from the cold volcanic rocks. [77] ocean is the repository for gases dissolved in the atmosphere, which are essential for the survival of many aquatic organisms. [78] as well as the sea water has an important influence on the global climate ; where they work and oceans large reservoirs of heat. [79] the changes in the temperature distribution in the oceans could significantly impact of climate change on sea level changes, such as the Niño-southern oscillation, known as "El Nino" phenomenon. [ 80]

The atmosphere

The average atmospheric pressure on the surface of the Earth to 101.325 kPa, at the height of trays of 8.5 kilometers. [81] It is worth mentioning that the atmosphere is composed of 78% nitrogen and 21% oxygen, as well as trace amounts of water and carbon vapor of carbon dioxide and particles other gas. This differs high troposphere (lower atmosphere) according to latitude, where the height ranges between 8 km at the poles and 17 km at the equator, so with some differences due to weather and seasonal factors. [82]

The existence of the biosphere of the planet has led to a change in their atmospheres; the metabolism or photosynthesis synthesis that relies on oxygen began 2.7 billion years ago which led to the formation of the atmosphere, which consists mainly of oxygen and nitrogen present now. This change has led to a proliferation of air inhaled organisms, and be the ozone layer that works is the magnetic field of the planet together to block sun's ultraviolet rays, which allows the existence of life on Earth. Other important functions of the atmosphere: water vapor and provide useful gases and help move the burning meteors before they hit the Earth's surface and adjust the temperature. [83] defines the recent phenomenon of such phenomena as the "greenhouse effect"; as the tiny particles found in the atmosphere helps in solitary thermal energy emitted from the Earth, leading to rising average temperatures on the earth's surface. It should be noted that carbon dioxide and water vapor, methane, ozone is one of the raids greenhouse for the land, it is not the existence of the greenhouse effect, the average temperature on the surface of the Earth will reach -18 ° C, has been non-existent life then. [66]

Weather and climate on the Earth's surface

Water vapor caused by the escalation of the vapors from the surface of the earth in a way that moves air patrol. When the weather allows moist air to escalate warm, the water contained in the air condenses, and then fall to the surface again in the form of rain and snow. [84] Thus, most of the water evaporated back again low-lying areas of the Earth's surface through rivers, which usually return to the ocean or collects in lakes. The water cycle of biological mechanisms that support the existence of life on the surface of the planet, as well as from the primary factors leading to the erosion of the terrain on the surface of the earth over geological periods. The rainfall amounts vary between several meters of water per year to less than a millimeter. It is worth mentioning that the air circulation in the atmosphere and features of topographic variation different temperatures contribute to determine the average amount of rain that falls on each region. [87] There is no known limits of the atmosphere of the Earth; as it becomes thinner gradually fading into outer space. That there are three-quarters of the mass of the atmosphere in the first eleven kilometers from the planet's surface. The lowest layer known as the "troposphere" or "bottom cover." The energy emitted from the sun heats this layer and the surface located underneath, leading to the air stretched, and then the hot air rises a little higher density and is replaced by cool air more intense. The result is the circulation of air in the atmosphere that directs the weather and climate through the re-thermal energy distribution. [84] [85] It consists of basic rotation belts in the atmosphere of the trade winds blowing in the tropical area below the latitude of 30 ° West and the wind blowing on mid-latitudes between 30 ° and 60 °. As ocean currents from the fundamental factors are also considered in determining climate, particularly the movement of water in the depths of the oceans that contribute to the distribution of thermal energy from the ocean, located at the equator to the polar regions. [86]

Earth can be divided into the same climatic conditions almost homogeneous belts, according to latitude. For example, it can belts, located the beginning of the equator and even polar regions divided into tropical and semi-tropical regions of moderate and polarity. It can also climate classification is also in accordance with the temperatures and amounts of rainfall as well as the classification of climatic regions according Bikes blocks a regular basis. [88] climate classification Koppen system consists (according to the amendment, conducted and Ldermir Koppen pupil "Rudolf Geir") of the five major groups namely: the tropics wet and dry and wet areas, which are located in the mid-latitudes, and regions of the continental and cold polar regions, which have been divided later to more specific areas. [85]

The upper atmosphere

Due to the presence of thermal energy on the planet, some of the molecules that are on the outer edge of the atmosphere of the planet increases its speed to the point where it escapes from the scope of the planet's gravity. This leads to leakage or escape from the atmosphere into space slowly, but always was. Because hydrogen gas be mild and The low molecular weight, the escape into space at a speed higher, and the escape rate is greater than the escape of gases other rate. [91] This is a hydrogen gas leak in the outer space of contributing to change the ground situation of factors the case of the initial reduction to the current state of oxidation. It is worth mentioning that the process of photosynthesis as a source of free oxygen, but some believe that it has shorthand such as hydrogen gas factors is a necessary precondition for the accumulation of oxygen in the atmosphere on a large scale. [92] Thus, the hydrogen gas's ability to escape from the atmosphere of a planet Earth may have influenced the nature of life on the planet. [93] at the present time, it is in the presence of rich gas oxygen atmosphere, most of the hydrogen gas turns into water before it has a chance to escape from the atmosphere to outer space. But because most of the hydrogen gas loss to the destruction of methane in the upper atmosphere. [94] divided the atmosphere above the troposphere usually to the stratosphere (the upper part of the atmosphere, mesosphere (middle atmosphere) and Iyrmosver (thermal cover). [83] Each a layer of the aforementioned classes depending on the temperature drop rate, which shows the extent of change in temperature according to altitude. this fade layer Alaksossador (the last layer in the atmosphere) behind these layers in the magnetosphere; where this is the point at which interacts field Magnetic solar Amaariyah. is the ozone layer important part of the atmosphere to sustain life on the surface of the planet, and the longer this layer is a component of the stratosphere (stratospheric), which protects the Earth's surface are part of the ultraviolet radiation. [89] this is called "the line Carman "the area above the ground at about 100 kilometers, which separates between the atmosphere and space. [90]

the magnetic field

This will be the Earth's magnetic field Almagentosevar magnetic cover which helps deflection in the solar wind on the Earth fine particles. Edge is just in front of the sun and the special reduction interval between the magnetosphere and surround the center by 13 times the radius of the planet. As results from the collision that occurs between the Earth's magnetic field and solar wind belts so-called "Van Allen" radiological and two concentric zones with a round protrusions present the minute particles charged energy. Once you enter the plasma (high gas ionization) to the magnetic poles, consists Twilight. [97] earth's magnetic field is formed on the magnetic field body almost bipolar, with the convergence of the poles of the magnetic field at the moment of the bipolar coordinates of the planet. According to the dynamo theory, the magnetic field of the planet breeding within the molten outer core layer; the heat in this place lead to the presence of convection movements of the material conductive heat, which leads to the generation of electrical currents. This leads in turn to generate the magnetic field of the planet. It is worth mentioning that the convective movements in the Earth's core are random nature of the change in the League align. This leads in turn to the reflections in the magnetic field at irregular intervals occur averaging a few times every million years. It is worth mentioning that another reversal in the magnetic field has occurred for nearly 700,000 years. [95] [96]

Orbit and rotation of the Earth

Rotation

Apart from meteors that enter the scope of the atmosphere and the moons that orbit in low orbits, the major phenomenon movements of celestial bodies in the sky of the planet the west occur at a rate of 5 ° / Q = 15 '/ d. It is worth mentioning that this ratio equal to the true diameter of the sun or the moon, which is calculated every two minutes; the apparent size of the sun and the moon will be almost equal. [103] [104] estimated the Earth's rotation period around its axis to the sun - the solar day average - about 86,400 seconds of the mean solar time. It is noteworthy that every second of these seconds is the longest of the second period in the international system slightly units; because the solar day is now little more than the solar day during the nineteenth century longer, due to the acceleration of the tides and the islands. [98] The Earth's rotation period of about centered according to the fixed stars, which was launched by the Commission today name interstellar medium. [99] estimated 86164.098903691 seconds of mean solar time (UT1) or (23 x 56 d 4.09053083288 s). As for the period of the Earth's rotation around itself in accordance with the moderation Rubaie Intermediate and Advanced, which some call an "astral today" or "astronomical," it is estimated 86164.09053083288 seconds of mean solar time (23 x 56 d 4.09053083288 s). [100] Thus, the astronomical day shorter of the day by about 8.4 interstellar fraction of a second. This can be determined by the length of the mean solar day period between the years 1623-2005 and 1962-2005 periods. [101] by resorting to "references to measure the global body rotation of the Earth." [102]

Orbit

A planet orbits the Earth around the sun, about 150 million kilometers every 365.2564 solar day average or astronomical year, which makes the sun appear to the viewer from the ground, moving east for the stars at a rate of 1 ° / day or Qatar, the sun or the moon every 12 hours. Because of this movement, it is, on average, the Earth takes 24 hours - the equivalent of a solar day - in order to be a complete cycle on its axis so that the sun returns to the meridian circle. The estimated average orbital speed of the planet at about 30 km / sec (108.000 km / h), which is considered sufficient speed to cover diameter distance of the planet (about 12,600 kilometers) in seven minutes and the distance to the moon (384,000 kilometers) in four hours. [81]

The moon revolves around the earth with the center of mass every 27.32 days, according to the Star in the background. When the above is added to the rotation of the Earth around the sun and the moon, the lunar month period (the period that stretches between the two satellites to be) about 29.53 day. Beholder notes for the land of the north celestial pole, the movement of the earth and the moon and all Doranhma be pivotal counterclockwise. But if one has to look better than the highest point of the North poles of the sun and the moon, the earth Vstbdo as if it revolves around the sun counterclockwise. The orbital and axial levels are not completely straight; where the Earth's axis is tilted 23.5 degrees from Taamayor on the ground level and the Sun, and tends ground level, and the moon is about 5 degrees away from the earth and the sun level. Without this tilt, there will be an eclipse and lunar eclipse every two weeks, and then alternately between the lunar and solar eclipses. [105] estimated the radius of influence of Earth's gravity area of ​​about 1.5 GB meters (1.5 million kilometers). [106] This is the maximum distance that is the influence of Earth's gravity is stronger than the sun and the planets furthest distance. It is worth mentioning that the objects must revolve around the earth within this radius, or they become uncontrolled due to the attractiveness of the sun disorder.

Chapters and the tendency of the Earth's axis

The land is located is the solar system in the Milky Way, where there are just 28,000 light years from the galactic center. The land is located at the moment is 20 light-years above the level of the equator of the galaxy on the Orion spiral arm. [107]

Given the tendency of the Earth's axis, the amount of sunlight reaching any given point on the Earth's surface varies over the year months; where solves the summer in the northern hemisphere when heading Arctic sun hand, and the onset of winter when it is moving the pole away from sunlight. During the summer, the day lasts longer and the sun is highest in the sky, while in winter the climate becomes more generally cooler in the daytime and it becomes shorter. Above the Arctic Circle, the situation has become extreme, because the sun does not shine at all but eliminates the polar night over 6 months. In the southern half of the ball shall be the exact opposite situation; where the South Pole in the direction opposite to the direction of the North Pole.

At the present time, the perihelion (closest point in the orbit of the planet or another celestial body to the sun) for the planet happen on January 3, almost, while happening apogee (the point at which the planet farthest from the sun) in the July 4 . But these dates change over time; and that given the advanced traffic and other tropical factors that follow regular patterns known as "Milankovitch cycles." This results in changing the distance between the Earth and the sun to increase the solar energy reaching the Earth at perihelion by an estimated 6.9% stage, compared to the thermal energy that reaches the planet when it is in the apogee stage, a further possible point from the sun. Since the southern part of the Earth tilted toward the sun almost at the same time when the Earth reaches the closest possible point from the sun, the Southern Hemisphere is receiving power sun larger than those received by the Northern Hemisphere throughout the year. But the impact of this matter is less important than the overall change in energy, which occurs due to the inclination of the Earth axis, as is the extra energy absorption due to the high percentage of water in the Southern Hemisphere. [110] According to astronomical rules, is determined the four seasons through coups (point in the orbit of maximum axial tilt toward the sun or away from) as well as the Equinox when the direction of tilt and direction toward the sun vertically. It is worth mentioning that the winter solstice occurs on December 21 and the summer solstice occurs on June 21, almost, and the vernal equinox occurs in about March 20, while the autumnal equinox in September 23 happened. [108] This will be the angle of inclination of the Earth relatively constant over long periods of time . However, the axis is also subject to ataxia (Shivers or irregular movements occur in the axis of the Earth by the sun and the moon) every 18.6 years. Also, the direction of the Earth's axis (not corner) also changed over time, moving in a circle to be a complete cycle every 25,800 annual session This phenomenon is called axial precession, this ring of progress is the difference between the cause of the astrological year and tropical year. He spoke these movements because of the different attraction of the sun and the moon when buckling located in the equator of the planet. If one looks at the poles of the earth, it is noted that the poles also Atzhzhan few meters on the surface of the earth. These polar movement consists of several periodic components called all quasi-periodic motion name. In addition to the annual component to this motion, there is no cycle occurs every 14 months known as "ataxia Chandler," a movement that plague the Earth's axis and rotation lasts about 14 months. This varies the speed of rotation of the Earth, resulting in a phenomenon known as the differing length of the daytime period. [109]

the moon

Caused by gravity between the Earth and the moon occurrence of the phenomenon of the tides on the earth's surface. This is the same effect on the Moon has led to Alanhsar Range: ie the rotation period are the same period it takes to be in the rotation around the Earth. As a result, it is always just one particular planet faces. During the rotation of the moon around the earth, the sun illuminates different parts of the face, leading to the emergence of different lunar phases. And inseparable part of the moon shining on the dark part of the route of the separation line between the solar segment illuminating the dark part. Due to tidal interactions that occur on the surface of the earth, the moon is from the sun by 38 millimeters per year approx. Over millions of years, these changes Mini-addition to increasing the length of the day on the planet by 23 fraction of a second each year-there will be tremendous changes. [111] For example, it is noted that during the Devonian Period (410 million years ago almost) there was 400 days a year and it was every day lasts 21.8 hours. [112] is the moon follower ground like a large planet, and a diameter of up to a quarter of the diameter of the planet. The moon is the largest in the solar system continued, and that relative to the size of the planet to him, this is called the disciples orbiting other planets satellite named after the satellite ground.

Moon significantly affect the evolution of life on Earth's surface, so by helping to moderate climate on the planet. Each of paleontology studies and simulations using computers show that the stability of a mile Earth's axis and its stability on this situation happens due to tidal interactions with the Moon. [113] Some theorists believe that without this stability to occur in the Earth's axis versus torque that occurs due to the sun and other planets on buckling located at the equator, the spindle may be fixed at random, leading to dramatic changes of the planet over millions of years, such as that with the planet Mars. [114] in the event that the Earth's rotation axis close to the surface virtual circuit to the ecliptic, it leads to very harsh weather occurring as a result of the very large seasonal variations that will occur; as a poles will go directly toward the sun during the summer and will go away from them during the winter. It is worth noting that scientists studying the planets and celestial bodies who have studied the impact of this matter on the planet, has a prediction that this could lead to the death of all the large-size animals and the eradication of plant life. [115], but this topic is still the subject of controversy, it has been resolved by future studies of Mars - the planet on which it is in a period and a tendency to spin axis like the Earth, but not followed by a large-sized moon, and its core is not liquid.

Beholder notes to the Moon from the Earth, it is long enough so that it appears Al form a clear shaped like the sun disk. It is worth mentioning that the size angular (or solid angle) of the two bodies are similar; because although the Qatar sun largest at about 400 times the diameter moon, it is also away from the Earth is approximately equivalent to 400 times the distance that spared the moon from the earth. [104] this would allow a total eclipse and annular eclipse on Earth.

It is the theory of the effect of bumping giant object of the most accepted theories that explain the origin of the moon. According to a theory that the moon may be a result of the collision of a primitive planet the size of Mars called "Thea" planet in its early stages. This is explained by the assumption (among other assumptions) the relative lack of iron metal and volatile elements on the surface of the moon, as well as the fact that indicate that the composition of the moon was almost identical to the Earth's crust formation. [116]

The validity of the planet for life

Biosphere [edit] called on the planet that is fit for a life of him he is good to settle even if it did not already lives. Earth believes necessary for the existence of water and basic conditions appropriate that can accumulate in which organic molecules vehicle and the energy needed to support and enhance the metabolism of food and the environment. [117] There are several factors that contribute to the provision of the necessary conditions for the establishment of life on the planet, these factors are in after the planet for the sun and its movement in the orbit and the lack of stability and the rate of rotation on its axis and deviation him and geological history and its atmosphere Permanent magnetic and scope condom. [118]

Tabieihiqal exploitation of land and resources that sometimes forms of life on Earth represents the biosphere. And it is generally believed that the biosphere has begun in the upbringing and formation about 3.5 billion years ago. The planet Earth is the only place in the universe in which the life. Even more, some scientists believe that the appropriate places for life, like Earth are rare in the universe. [119] The biosphere is divided into a number of dynamic environments where a large number of plants and animals similar lives. It is the interval between the factors critical environments Latitude circle and land elevation above sea level. And devoid of vital terrestrial environments in the Arctic or the Antarctic Circle or high elevations of any form of life, whether animal or vegetable, while there is a greater variety of life forms at the equator. [120]

Land needed for the human resources in order to provide exploited to achieve useful goals. Some of these non-renewable resources such as mineral fuels, are characterized by these resources could not be restored in a short period of time. It has been getting large amounts of fossil fuel deposits of the earth's crust, which consists of coal, oil, natural gas and methane compounds. Human has used these deposits to produce energy and as a raw material for chemical reactions. It consists of mineral raw materials also in the crust of the planet through a process to be ore or earth metals from corrosion layers and geological movements Altknunah panels. [121] This is a material rich sources of many metals and other useful elements.

Biosphere on Earth provides products for many vital for a person, for example, but not limited to: food, wood, drugs and medicines, oxygen and re-exploit a lot of organic waste and residues. Based ecosystem depends on land and on the presence of soil, clean water surface, while for the private ecosystem oceans depends on dissolved nutrients washed from the land. [122] rights and lives on land, through the use of primary building materials in the construction of shelters intended for housing. In 1993, the proportions of the human use of the land was as follows:

Natural and environmental risks

Exposed to large tracts of land to severe weather conditions such as cyclones and tropical storms, and tropical Aloaseijer. As many places exposed to earthquakes, landslides, seismic waves freely tsunami and explosions Barakanahooasir repressive and depressions are ground and snow storms, floods, droughts and other natural disasters.

In addition, it exposed many of the areas where human inhabited by many kinds of pollution that human-induced himself, such as air and water pollution, acid rain, are toxic substances and the disappearance of the plant by the life (and it is due for many reasons, including overgrazing, deforestation and desertification) and the disappearance of wildlife and extinction some kinds of animals, soil erosion, lack of some useful elements out and the depletion of the soil and the onset of extraneous objects.

Scientists agree that there is a close link between human activities and global warming due to increase carbon dioxide emissions from factories and exhaust means of transport increased, operating on fuel. It owns the land's population, numbering about 6 billion people now, about 500 million cars and a bus the whole issue of carbon dioxide and other harmful gases, all of which works to increase these gases accumulate in the atmosphere. This is expected to lead to serious changes on the ground, such as high temperature and Dhubanalonhar glacial melting Antarctic ice, which would lead to increased water levels in the oceans and seas, which means that the islands are endless and all low-such as the Netherlands land will be doomed to drowning . As the severe change in temperature will increase the intensity of hurricanes and cyclones, and increase the proportion generated by the mass return. [123]

Human Geography

The study of cartography and geography among the sciences that have been allocated throughout history to describe the earth. Surveys have appeared (to identify the places and spaces between them) and navigation (locating things and trends) Besides these two flags, which worked to provide accurate information. The number of the world's population in November 2008 about 6.74 billion people. Indicators show that the global population density will reach in 2013 to 7 billion, and in 2050 this figure will rise to 9.2 billion. [125] It is expected that most of the population growth in developing countries are. The population density varies from place to place in the world, but increased significantly in the continent of Asia. It is expected that by 2020 about 60% of the world's population live in cities rather than rural areas. [126]

Moreover, it is likely that less land area to the price of the current area; any human would not be able to live only on this space, and the reason for this is that three-quarters of the Earth's surface is covered by oceans, in addition to that would be half the land has shifted either to the desert barren (14%), [127] and the rest will remain a highlands and mountains (27%) or the terrain is suitable for live human on them. [128] maximum human colonies to the north is Alert city in Olzimaar island in Nonavat in Canada, [129] (when length of 82 degrees and 28 minutes) line, and a maximum of the south is the Amundsen-Scott South Pole Station in Antarctica at (90 degrees south).

Operates independent sovereign states all the land on the planet, except for some parts of Antarctica. In 2014, there were 206 independent sovereign, including one hundred and ninety-three at the United Nations member states occupy the land the state, [130] In addition, there are 59 province-state and a number of self-governance and land independent regions humans differs from the rule. [ 72] Historically, it did not happen that ruled the land by the government and Ahdhmsatrh on the whole world in spite of the outbreak of many conflicts between states in order to control the world, but all attempts failed. [131] the United Nations is a global organization working to resolve disputes between nations and thus avoid the outbreak of armed conflict, [132] However, they are not considered a world government. And despite the fact that the United Nations organization that provides a way for the application of international law and despite that sometimes there is unanimous consent of its members to intervene Aeksri, [133] it is considered basically a forum for international diplomacy. Was the first man to orbit the earth is Yuri Gagarainfe April 12, 1961. [134] In 2004, the 400-person tours to outer space and then returned back the same way to the Earth's orbit, has stepped onto the feet of 12 people, including the surface of the moon. [135] [136] [ 137] the people who live in space for a long time understand the workers in the international space Station, and is altered space station crew, which consists of three members every six months. [138] was the longest trip of human into outer space in 1970 when cutting crew spaceship Apollo 13, which consists of three members, 400.171 km away from the earth's surface. [139] [140]

In human culture

Often the land was being raised to the rank of worship or sanctification and make them gods. In many cultures, the mother of the gods, also known as Mother Earth, is portrayed as the goddess of fertility. And remember creation myths in many religions, the story of the creation of the earth by a group of gods with supernatural powers. Confirms many religious groups, in the Christian doctrine or Islam, [143] that different interpretations of how to create a ground mentioned in the Scriptures actual fact and should be considered in line with the discoveries of modern or replace conventional scientific explanations concerning the science formation of the Earth and the origin of life on and development. [144] opposes scientific communities [145] and other religious groups such interpretations. [146] [147] [148] [149] Among the most famous high-profile example of this is the controversy over the origin of Alkhalq.oma Arabic word now used to describe the planet "Earth" are used in Arabic language since the fourth century at least, it has been mentioned in the Koran about 444 Mrh.achtq earth English name "Earth" from the word "erda" it Onkulosacksona origin, which means the soil or surface that we're on.