Earth (English name: Earth; Latin: Terra is distance Sun 150 million miles from the third one planet It is also the only one known to breed and support life Celestial body . About 29.2% of the Earth's surface is made up of mainland and island constituent terrene Most of the remaining 70.8% were ocean , bay And other saltwater bodies are covered, too lakes , glacier , river And other freshwater bodies, especially glaciers, which together form hydrosphere . Most of the earth Polar region It's all covered in ice. The outer layer of the Earth is divided into several rigid tectonic plates that migrate across the surface over millions of years, while its interior remains active.

The Earth's atmosphere is mainly composed of nitrogen and oxygen Make up. Tropical region Receives more solar energy than the polar regions and passes through the atmosphere and Ocean circulation Redistribute. Greenhouse gas In regulation Surface temperature It also plays an important role. The climate of a region is not only determined by latitude The decision is also determined by factors such as altitude and proximity to the area and the sea. Tropical cyclone , thunder , Heat wave Such severe weather occurs in vast areas and has a great impact on life.

The gravitational pull of the earth will match Outer space Interact with other objects, especially seleno It is unique to the earth Natural satellite . Earth orbit Sun One orbit takes about 365.25 days. The Earth's axis of rotation is tilted relative to its orbital plane, creating seasons on Earth. Caused by gravitational interactions between the Earth and the moon tide It stabilizes the orientation of the Earth on its axis and gradually slows down its rotation. ^[34]

The earth is the common home of human life, Humans There's only one Earth. ^[35]

Chinese name: The earth
Foreign name: English name : Earth
Greek : Γαῖα (Gaia)
Latin : Terra
alias: Blue star , Third planet
categorize: planet
Mass and quantity: 5.97237 ✕ 10 24 kg
Mean density: 5507.85 kg/m³
Straight diameter: 12742 km
Surface temperature: 14 ℃ (287 K)
Escape velocity: 11.186 km/s
albedo: 0.367 (Geometry, 0.306 sphere)
Rotation period: 23 hours, 56 minutes and 4 seconds (Sidereal day)
Right ascension: To be defined
declination: + 90 °
Semi-major axis: 149598023 km
eccentricity: 0.0167086

Period of revolution: About 365.24219 days
Flat near point Angle: 358.617 degrees
Orbital inclination: 7.155 degrees
Longitude of ascending node: -11.26064 degrees
volume: 1.0832073 x 10 antispasmodics km after
Aphelion distance: 152097701 km
Perihelion distance: 147098074 km
Orbit circumference: 924375700 km
Perihelion Angle: 114.20783 °
Average velocity of revolution: 29.783 km/s (107,218 km/h)
Maximum velocity of revolution: 30.287 km/s (109033 km/h)
Minimum revolution velocity: 29.291 km/s (105,448 km/h)
Cosmic velocity: 11.186 km/s (39600 km/h)
Equatorial circumference: 40075.017 km
flattening: 0.0033528
Area product: 510072000 km²
Angle of rotation: 23.44 °
satellite: seleno

catalogue

name

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EDITOR

The English name Earth comes from Middle English Its history dates back to Old English (often Orðe), in The Germanic language family There are cognates in all languages, their original The Germanic language The root is "*erþ". Latin is called "Terra", for the ancient Roman mythology of the earth goddess Thea The name of... In Greek, it is called Γαῖα (Gaia), after the Greek goddess of the earth Gaea The name of... ^[1]

The Chinese word "earth" first appeared in the eastern period of Western learning in the Ming Dynasty, and it was first introduced by the Italian missionary Matteo Ricci (1552-1610). Universal map of the world The word is used in ". In the late Qing Dynasty, Western modern science was introduced into China. Earth circle theory Gradually accepted by the Chinese people, the word "earth" (also known as "earth") was widely used, and the article "Earth Talk" was published in the first month of the publication.

Revolution and rotation

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EDITOR

revolution

Earth around the sun revolution The average distance of its orbit from the Sun is about 150 million kilometers (93 million miles) every 365.2564 Mean solar day (365 days 6:9:10 seconds) Turn around, called one Sidereal year . In 1990, Voyager 1 captured an image of Earth (a faint blue dot) from 6.4 billion kilometers (4 billion miles) away. This revolution causes the Sun to move eastward about 1° per day relative to the star, which is equivalent to the Sun or Moon moving every 12 hours Apparent diameter . Because of this motion, the Earth takes an average of 24 hours, or one solar day, to complete one rotation on its axis, allowing the sun to pass through the meridian again. Earth revolution At an average speed of about 29.8 km/s (107,000 km/h), it is possible to travel 12,742 km (7,918 mi) in seven minutes, equivalent to the diameter of the Earth. It can travel about 384,000 kilometers in about 3.5 hours Earth-moon distance . ^[2]

The orbit of the Earth

In modern times, Earth's perihelion and aphelion They occur around January 3 and July 4 each year. Due to the precession sum Orbit parameter The impact of the change, these two dates will change over time. This change is characterized by periodicity, that is The Milankovitch hypothesis . The change in the distance between the Earth and the Sun causes the Earth to gain 6.9% more solar energy as it moves from aphelion to perihelion. Because the southern hemisphere always faces the sun near perihelion at the same time each year, the southern hemisphere receives a fraction of the Sun's energy over the course of the year The northern hemisphere A little more. However, this effect is much smaller than the influence of the rotation Angle on the total energy change, and most of the received energy is The southern Hemisphere A high proportion of the surface water is absorbed.

Relative to the background stars, the Moon and Earth orbit each other every 27.32 days barycenter One revolution. Since the Earth-moon system orbits the Sun together, the interval between two adjacent moons, i.e Synodic month The average period is 29.53 days. Seen from the North Pole of the celestial sphere, the moon's orbit around the Earth and their rotation are counterclockwise. From the high point beyond the Earth and the sun's North Pole, the Earth also orbits the sun in a counterclockwise direction, but the orbital plane of its orbit (i.e ecliptic ) and the Earth equator It does not coincide - the ecliptic plane and the equatorial plane present an Angle of 23.439281° (about 23°26'), which is also the Angle between the spin axis and the common axis, known as the orbital inclination, axial inclination, or orbital inclination The intersection Angle of the yellow . The plane of the moon's orbit around the Earth ( White path The Angle to the ecliptic is 5.1°. Without these tilts, there would be an alternate solar eclipse and a lunar eclipse every month. ^[2]

Earth's gravitational sphere of influence ( Hill ball The radius is about 1.5 × 10 6 Kilometers (930,000 miles). An object must fall within this range in order to be considered to be orbiting the Earth, otherwise its orbit would become unstable due to gravitational perturbations from the Sun and could break free from Earth. The entire solar system, including Earth, is located in Milky Way galaxy Flat (plane) Galactic circle About 20 light-years above Orion arm Inside, it orbits the center of the Milky Way at a distance of 28,000 ly.

autorotation

The average of the Earth relative to the sun Rotation period A mean solar day is defined as mean solar time of 86,400 seconds (equal to SI86,400.0025 seconds). Because of the tidal slowdown, Earth's solar day is already slightly longer than it was in the 19th century, between 0 and 2 SI ms per day. International Earth Rotation Service (IERS), measured in seconds in the International System of Units from 1623 to 2005 and 1962 to 2005, determined Mean solar day The length of. ^[3]

The rotation period of the Earth with respect to the sun is called one Sidereal day According to the IERS, 1 sidereal day is equal to Mean solar time (UT1) 86,164.098903691 seconds, or 23 hours, 56 minutes, 4.098903691 seconds. In astronomy, the Earth is often compared to Flat equinox The rotation period as a sidereal day in 1982 was mean solar time (UT1) 86164.09053083288 seconds, i.e. 23 hours 56 minutes 4.09053083288. On account of Spring equinox Will be because precession This sidereal day is about 8.4 milliseconds shorter than a true sidereal day.

As seen from Earth, objects in the sky move at 15° per hour, or 15' per minute Angular velocity Moving westward (except for satellites in low orbit and meteors in the atmosphere). An object near the celestial equator moves about the same distance every two minutes as the apparent diameter of the Moon or sun as seen from the surface of the Earth (both are nearly identical).

Angle of rotation

Orbital inclination The presence of the Earth around the sun, the sun directly at the point The Tropic of Capricorn and The Tropic of Cancer This is a tropic year with a duration of 365.24219 mean solar days (i.e. : 365 days, 5 hours, 48 minutes and 46 seconds). The length of day and night and the height of the sun vary at different latitudes on the Earth, making these areas receive more or less the same amount of sunlight in a day Solar radiation The total amount changes, resulting in season Change. when North Pole Relative to South Pole Closer to the sun, the point of direct sunlight is The northern hemisphere At this time, the northern Hemisphere day is long and the night is short, and the sun's altitude Angle is large Summer half year ; The southern Hemisphere The days are short and the nights are long, and the sun's altitude Angle is small Winter half year ; And vice versa. North of the Tropic of Cancer The north temperate zone The sun always rises in the southeast and sets in the southwest; in The south temperate zone The sun rises in the northeast and sets in the northwest.

During the summer half of the northern and southern hemispheres, latitude The higher the altitude, the longer the days, the shorter the nights, in the polar circle may appear all day day situation, called Polar day . Near the pole, six months of the summer half are in perpetual daylight; The higher the latitude in the winter half year, the shorter the days and the longer the nights, and the situation that the polar circle may be dark all day is called Polar night . It is polar night in the winter half year near the pole. ^[2] In a year of regression, the sun's direct point is The Tropic of Cancer Move between. The day when the direct point falls on the Tropic of Cancer and the Tropic of Capricorn solstice . It crosses the equator twice and is called equinox . In the Northern Hemisphere, the winter solstice occurs around December 21, the summer solstice around June 21, the spring equinox usually on March 20, and the autumn equinox usually on September 22 or 23. In the southern hemisphere, Vernal equinox , Autumnal equinox ; Summer solstice , Winter Solstice Festival The date is the opposite of the northern Hemisphere.

Because the earth is not ideal sphere The ecliptic plane, the white plane, and the equatorial plane all have intersecting angles, which the Sun and moon exert on the Earth Moment of force There is a component perpendicular to the angular momentum of the rotation, which causes the Earth to rotate at the same time precession Its period is 25,800 years, resulting in Sidereal year and Tropical year The difference, i.e precession . The tilt Angle of the earth almost does not change with time, but due to the changes in the position of the sun and the moon relative to the Earth, the external force on the Earth changes, and the tilt Angle of the earth will still be slight and irregular during rotation and precession nutation Its maximum periodic component is 18.6 years, which is consistent with the precession period of the lunar node. The earth is not ideal Rigid body , receive Geological change , Atmospheric motion As a result of these effects, the Earth's mass distribution will change, and the rotation pole will also shift slightly relative to the Earth's surface, changing the position of the pole by several meters per year, and the pole has shifted by about twenty meters since 1900. This drift is called Polar motion . The polar shift is a quasi-periodic motion, with the main periodic components consisting of a motion with a period of one year and a motion with a period of 14 months. The former is often thought to be related to the movement of the atmosphere, and the latter is called Chandler swing . Because the Earth's rotational angular velocity is greater than the angular velocity of the moon and the Earth, it is affected Tidal friction The angular speed of the Earth's rotation slowly decreases with time, in other words, the time of day gradually becomes longer.

satellite

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EDITOR

seleno

seleno Is the Earth's natural satellite, because the ancient night can provide a certain lighting function, also often called "moon", the diameter of the moon is about a quarter of the diameter of the Earth, the structure and Terrestrial planet Similar. The moon is the largest satellite in the solar system by volume. though Pluto and Charon The ratio between the two is bigger, but Pluto belongs to Dwarf planet . The gravitational interaction between the moon and the earth is caused by the Earth Tidal phenomenon The main reason while the moon is being Earth Tidal locking Therefore, the rotation period of the moon is equal to the period of revolution around the Earth, so that the moon always faces the Earth with the same side. Changes in the side of the moon illuminated by the sun and facing the Earth, resulting in Phase of the moon The dark part and the light part are separated by the terminator. Due to the tidal interaction between the Earth and the Moon, the moon gradually moves away from the Earth at a distance of about 38 millimeters per year, and the length of the Earth's rotation increases by about 23 microseconds per year. Over millions of years, these small changes add up to significant changes. For example, in Devonian period The year had 400 days, while the day was only 21.8 hours long. ^[4]

seleno

The moon's regulation of Earth's climate could dramatically affect the development of life on Earth. paleontology Evidence and computer simulations show that Earth's axial tilt is stabilized by tidal interactions with the Moon. Some theorists believe that without this stabilizing force to counter the torque generated by the sun and other planets on Earth's equatorial bulge, the Earth's axis of rotation would point to it chaos Impermanence; Mars is a case in point. The diameter of the sun is about 400 times that of the Moon, but the sun is also 400 times farther away from the Earth, so the moon and Sun are almost the same size as seen from Earth. This causes the angular diameters (or solid angles) of the two objects to match, so that they can be observed from Earth Total solar eclipse and Annular eclipse . About the origin of the moon, Giant impact hypothesis Is the most supported Scientific hypothesis But there are still some unexplained problems with this hypothesis. The hypothesis is that 4.5 billion years ago, an object the size of Mars Theia It collided with the early Earth, leaving behind debris that formed the moon. This hypothesis explains the moon's lack of iron and iron relative to Earth Volatile element And the fact that its composition is almost identical to the Earth's crust. ^[5]

Artificial earth satellite

Artificial earth satellite It's a spacecraft built by humans to orbit the Earth. As of early August 2020, Earth has 6,613 satellites in orbit, including Pioneer 1, the oldest surviving US satellite in Earth's orbit, and more than 300,000 pieces of space junk in orbit around the Earth. The world's largest artificial satellite is International Space Station (International Space Station). ^[6] On April 12, 1961, Yuri Alexievich Gagarin Yuri Alekseyevich Gagarin became the first human to reach Earth's orbit. As of July 30, 2010, a total of 487 people have been in space and orbited the Earth, including 12 who have participated Apollo program And walk on the moon. Under normal circumstances, International Space Station The membership is made up of six people, and members are generally replaced every six months. Apollo 13 During its 1970 mission, it flew 400,171 km from Earth, the farthest distance ever traveled by a human being.

satelloid

In addition to the moon and satellites, Earth has at least five co-orbiting asteroids (quasi-satellites), four of which are asteroids that orbit the Sun in Earth's orbit Cruithne (3753 Crutithne), 2002 AA29 , 2016 HO 3 And guide the earth The Lagrange point L 4 the Trojan asteroid 2010 TK 7 . A near-Earth asteroid just five meters in size 2006 RH120 It gets closer every 20 years or so Earth-moon system Once, as it approaches, it will briefly enter orbit around the Earth. ^[7]

History and future

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EDITOR

Earth formation

An artistic imagination of the protoplanetary disk of the early solar system

Earth history Very long ago. On the basis of Radiocarbon dating The solar system formed about 45.6±0.08 million years ago, ^[8] The original Earth formed about 45.4±0.04 million years ago. In theory, the formation of the sun began 4.56 billion years ago with a giant cloud of hydrogen Molecular cloud the Gravitational collapse Most of the collapsed mass is concentrated in the center and formed Sun ; The rest of it rotates and flattens, forming one Protoplanetary disk And then formed planet , satellite , asteroid , comet , meteoroid And other Solar system small body . Nebular hypothesis Claims that formed the earth planetesimal Left over from accretion collapse gas A mass of ice and dust one to ten kilometers in diameter. This material grew over 10 to 20 million years, eventually forming the protoEarth. ^[9] The nascent surface of the Earth was formed by magma The composition of the "ocean".

The moon formed about 4.53 billion years ago, ^[10] Research on the origin of the moon is inconclusive, and the most popular is Giant impact hypothesis . ^[11] The hypothesis is that there's a star called Theia The object was about the size of Mars and 10 percent the mass of Earth. The collision caused a huge explosion. The material exploded into space, where it accreted to form the Moon, and some of Theia's mass melted into the Earth. About 4.1 billion to 3.8 billion years ago, the Earth-Moon system entered the late heavy bombardment period, numerous asteroids hit the surface of the moon, causing huge changes in the surface of the moon, and it is assumed that the Earth also suffered a lot of impacts at that time.

from Archaean Eon As the Earth's surface began to cool and solidify, forming solid rock, Volcanic eruption The released gas forms Secondary atmosphere . The initial atmosphere was probably composed of Water vapour , Carbon dioxide , nitrogen The evaporation of water vapor accelerated the cooling of the surface, and when it was sufficiently cooled, the rain continued for thousands of years, filling the basin and forming the ocean. While heavy rains reduce water vapor in the air, they also remove a lot of carbon dioxide from the atmosphere. In addition, asteroids, protoplanets and comet Water and ice are also a source of water. The Dim Sun paradox states that while the early sun was only about 70 percent as bright as it is today, there were enough greenhouse gases in the atmosphere to keep liquid water in the oceans from freezing. About 3.5 billion years ago, Earth magnetic field The appearance helps prevent the atmosphere from being Solar wind Peel off. Its outer layer cools and solidifies, and in atmosphere The crust is formed by water vapor. There are two models that explain the formation of land, one that sees continuous growth of land, and the other, more likely model, that sees rapid formation of land early in Earth's history and then maintenance to the present day. The heat inside is constantly lost, driving Plate tectonics Movement forms continents. On the basis of Continental drift hypothesis Over hundreds of millions of years, the supercontinent has broken up and broken up three times. About 750 million years ago, the earliest known supercontinent The continent of Rodinia It began to break apart and then coalesced between 600 and 450 million years ago The continent of Panocia And then merged into Pangea It finally split about 180 million years ago. The Earth is in the midst of a Pleistocene epoch that began 2.58 million years ago Ice age The middle and high latitudes undergo several cycles of freezing and thawing, which occur every 400,000 to 1 million years. The last time the continent froze was about 10,000 years ago. ^[12]

Life evolution

Earth provides the only one that can sustain the known Life evolution The environment. High-energy chemical reactions around 4 billion years ago are thought to have produced self-replicating molecules, and another 500 million years later the common ancestor of all life emerged and then diverged bacteria with archaea . Early life forms developed the ability to photosynthesize, which can be used directly Solar energy And release it into the atmosphere Breath . The accumulated oxygen in the atmosphere is emitted by the sun Ultraviolet light The effect is formed in the upper atmosphere ozone (O 3 ), and then appeared Ozone layer . Early life takes prokaryote The form exists. On the basis of Endosymbiosis theory In the process of life evolution, some small cells are swallowed into large cells, and are co-born in large cells, becoming large cells organelle Thus forming a relatively complex structure Eukaryotic cell . After that, the cells in each part of the cell community gradually differentiated into different functions, forming a true Multicellular organism . As the ozone layer absorbed harmful ultraviolet rays from the sun, the land became suitable for life, and life began to multiply on the land. The earliest known fossil evidence of life is Western Australia Fossil microbial MATS from 3.48 billion years ago in sandstone, West Greenland metamorphism Clastic rock From 3.7 billion years ago graphite . ^[13]

Dr. Joseph Kosivenk first suggested in 1992 that it was between 750 million and 580 million years old Neoproterozoic Glacial epoch The Great Ice Age When intense glacial activity left most of the Earth's surface under ice, it was for Snowball Earth (Snowball Earth) hypothesis. It happened 542 million years ago Ediacaran The final extinction event, followed by the final extinction event Cambrian explosion of life The diversity of multicellular organisms on Earth has skyrocketed (e.g trilobite , anomalocenid Etc.). Cambrian period After the explosion, Earth experienced five more Mass extinction Event. Of these, 251 million years ago Permian-triassic extinction event It's the largest in known geological history Species extinction Event; The last mass extinction occurred 66 million years ago Cretaceous-paleogene extinction event The asteroid impact made non-birds Dinosaur And other large reptiles went extinct, but some smaller animals survived, as was the case at the time shrew The same size mammal . Over the past 66 million years, mammals have continued to diverge. Millions of years ago, African ape-like animals (e.g The Tugen people Learned to stand upright. So they can be used better tool And communicate with each other to get more nutrition and stimulation, brain And it became more and more developed and eventually evolved into Humans . Human aid agriculture The development of civilization has enjoyed a quality of life unmatched by any other species on Earth, which in turn has affected the Earth and the natural environment. ^[14]

Future evolution

In 1.5 to 4.5 billion years, the tilt of the Earth's axis could change by as much as 90 degrees. It is assumed that complex life on the surface of the Earth is still young, and activity can continue to reach a maximum and last for about 700-800 million years. However, if the oxygen in the atmosphere disappeared completely, this time period would be extended to 2.3 billion years. The fate of the Earth in the distant future is closely linked to the evolution of the sun, along with Solar core the hydrogen continue Nuclear fusion generate helium The sun's luminosity will continue to increase slowly, predicted to increase by 10% after 1.1 billion years and by as much as 40% after 3.5 billion years, and the intensity of solar thermal radiation will also continue to increase. According to climate models, the Earth's surface will eventually rise due to solar radiation, with severe consequences, initially in the tropics and then to the poles, and over time, the oceans will evaporate and disappear.

Rising Earth surface temperatures will accelerate inorganic Carbon cycle Reduce atmospheric carbon dioxide levels: In about 600 million years, C3 plants will be out of the Earth's life stage; In about 800 million years, the amount of carbon dioxide in the atmosphere will gradually drop to 10 parts per million, and without the evolution of photosynthesis, C4 plants will be deprived of their right to survive. The absence of vegetation would reduce the oxygen content of the Earth's atmosphere, and the Earth's plants and animals would become extinct within millions of years. After that, it is expected that in more than 2 billion years, the surface water will completely evaporate, and the average temperature of the Earth will exceed 100°C. Even if the sun is always stable, because Mid-ocean ridge Less water vapor comes out, and after about 1 billion years, 27% of the sea water will enter mantle The decrease in ocean water makes the temperature change too drastic for complex life.

5 billion years later, after the sun enters the red giant phase, the earth will be burned to the ground.

Seven billion years later, the sun evolved into Red giant star At this point, the Earth's surface is no longer capable of forming complex molecules. Models predict that the Sun will expand to about 234 times its current radius, or about 1 astronomical unit (150 million kilometers), leaving the fate of Earth unclear. When the sun becomes a red giant, it loses 30 percent of its mass. So if you don't consider Tidal force When the sun is at its largest, the Earth moves about 1.7 AU (250 million km) away from the Sun, escaping its fate of falling into the expanding sun's outer atmosphere. But even if that were true, the sun's peak brightness would be 5,000 times greater than it is today, and the rest of life on Earth would be destroyed by the sun's rays. A simulation conducted in 2008 showed that the Earth's orbit would change due to Tidal effect As a result, it falls into the atmosphere of the Sun, which has become a red giant, and eventually evaporates. ^[15]

trait

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EDITOR

form

Earth shape It is roughly ellipsoidal. The effect of the Earth's rotation causes a slight flattening along the axis that runs through the poles and a slight bulge near the equator. ^[16] From the center of the Earth, the equatorial radius is 43 kilometers (27 miles) higher than the polar radius. Therefore, the farthest point on the Earth's surface from the Earth's center of mass is not the highest Mount Everest It's Ecuador on the equator Mount Chimborazo The top of the mountain. The average diameter of the Earth's reference ellipsoid is about 12,742 km (7,918 mi), equal to about (40,000 km)/π, an integer not coincidentally, but because the original definition of the unit of length meter was one ten-thousand of the distance between the equator and the North Pole on the longitude passing through Paris, France. Somewhere on the equator at sea level Acceleration of gravity The value of ga=9.780m/s^2, the value of the acceleration of gravity at a certain sea level in the Arctic gb=9.832m/s^2, the global standard value of acceleration of gravity g=9.807m/s^2, Earth rotation The cycle is 23 hours, 56 minutes and 4 seconds ( Sidereal day T=8.616×10^4s.

Due to local fluctuations, the Earth deviates slightly from the ideal ellipsoid, but on a planetary scale, these fluctuations are small compared to the Earth's radius, with a maximum deviation of only 0.17%. The Mariana Trench, located 10,911 meters (35,797 feet) below sea level, diverts only 0.14 percent from Mount Everest, which is 8,844 meters (29,016 feet) above sea level. If the Earth were shrunk to the size of a billiard ball, places like large mountains and ocean trenches would feel like tiny blemishes, while most of the rest, including the Great Plains and abyssines, would feel smoother. The total area of the Earth is about 510.1 million square kilometers, of which about 29.2% (148.94 million square kilometers) is land and the remaining 70.8% (3611.32 million square kilometers) is water. Land is mainly in the Northern Hemisphere and there are five continents: Eurasia , African continent The American continent, Mainland Australia and Antarctic continent There are also many islands. The ocean includes Pacific , Atlantic , The Indian Ocean , The Arctic Ocean and Antarctic Ocean Five oceans and their associated seas. The coastline is 356,000 kilometers. Lowest point on land: Dead Sea (-418 m), lowest point in the world: The Mariana Trench (-11,034 m), highest point in the world: Mount Everest (8848.86 m)

Chemical composition

The total mass of the Earth is about 5.97×10 24 Kilograms, about 60 trillion billion tons. The main components of the earth Chemical element There are iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), aluminum (1.4%); The remaining 1.2% is other Trace element , for example tungsten , gold , mercury , fluorine , boron , xenon Let's wait. Due to mass stratification (concentration of higher mass towards the center), it is estimated that the main chemical element constituting the Earth's core is iron (88.8%), and other components Earth's core Elements include nickel (5.8%) and sulfur (4.5%), as well as trace elements with a total mass of less than 1%. constitute mantle The main minerals include pyroxene (Chemical formula (Mg,Fe,Ca,Na)(Mg,Fe,Al)(Si,Al) 2 O 6 ), olivine (Chemical formula (Mg,Fe) 2 SiO 4 ), etc. ^[17]

As for Earth's crust The chemical composition of oxygen Is in the crust abundance The highest element, 46 percent. Oxygen compounds in the earth's crust include water , Silicon dioxide , Calcium sulfate , Calcium carbonate , Aluminium oxide The 10 compounds with the highest content in the crust and most of the compounds that make up the common rocks in the crust are oxygen-containing compounds. Some rocks are fluoride , sulphide and chloride But the total amount of fluorine, sulfur, and chlorine in any given rock layer is usually much less than 1%. Accounting for more than 90% of the volume of the superficial crust Igneous rock Mainly composed of silica and silicate Constitute. Geochemist Frank Wiggeville Clark calculated on the basis of 1,672 analyses of various rocks and concluded that 99.22% of the rocks are listed in the table below oxide Composition, there are also other less content of components.

Internal structure

The interior of the Earth, like other terrestrial planets, can be determined by chemical properties or physical ( rheology Properties are divided into several layers. However, the earth's Core , Outer core There is a clear difference, which is not a feature of other terrestrial planets. The outer layer of the earth is made up of silicate minerals Earth's crust There's a layer of sticky solid underneath mantle . The boundary between the mantle and the crust is The Moho discontinuity . The thickness of the Earth's crust varies with location, ranging from 6 km on the ocean floor to 30 to 50 km on land. The crust and mantle The cooler, harder upper layer is collectively called lithosphere , plate It was also formed in this area. Below the lithosphere is less viscous asthenosphere The lithosphere slides just above the asthenosphere. Major changes in the crystal structure of the mantle occur between 410 and 660 kilometers below the surface, which are compartments Upper mantle and Lower mantle The transition zone. Below the mantle is the core-mantle boundary that separates the mantle from the Earth's core. Gutenberg discontinuity ), followed by a very low-viscosity liquid outer core, and at the innermost is a solid inner core. The inner core may be rotating at a slightly faster angular rate than the rest of the Earth, by about 0.1-0.5 ° per year. The inner core has a radius of 1220 km, which is about one-fifth the radius of the Earth. ^[18]

The earth

Magnetic field and magnetosphere

There is stillness in and around the earth Magnetic field . According to the multipole expansion of the static magnetic field, if the Earth is approximated as one A magnetic dipole , of its Magnetic moment The size is 7.91 x 10 15 T m 3 , Geomagnetic axis Direction and Axis of rotation Approximately coincident but slightly off, the Angle between the two is called Geomagnetic declination . Formed at the intersection of a plane perpendicular to the magnetic axis and the Earth's surface Geomagnetic equator On the circle, the magnetic induction intensity is about 3× 10 5 - T, where the geomagnetic axis intersects the Earth's surface, Magnetic induction intensity About twice as high as at the geomagnetic equator. On the basis of Dynamo hypothesis Geomagnetism mainly comes from the movement of conductive fluids composed of iron and nickel in the Earth's core. In the outer core of the Earth's core, hot, conductive fluids are subjected to convection from the center outward Geostrophic deflection force Formation of the role of vortex To generate a magnetic field. The magnetic field generated by eddy currents will have a reaction on the flow of the fluid, so that the movement of the fluid and even the magnetic field generated by it will be approximately stable. But because the convective motion itself is unstable, the direction of the geomagnetic axis will change slowly and irregularly, resulting in Geomagnetic reversal . The cycle of geomagnetic reversals is irregular and can occur several times every million years, with the most recent reversal occurring 780,000 years ago Buronis-matsuyama inversion . ^[19]

The area of geomagnetic influence in space is called magnetosphere . Solar wind The ions and electrons are deflected by the magnetosphere and therefore cannot directly hit the Earth. The pressure of the solar wind compresses the region of the magnetosphere near the Sun to 10 Earth radii, while the region away from the Sun extends into a tail shape. The solar wind blows into the sunny side of the magnetosphere at supersonic speeds, creating a bow shock wave that slows down the solar wind, converts some kinetic energy into heat, and heats up the nearby area. in ionosphere Above, the low-energy charged particles in the magnetosphere form the plasma layer, whose motion is dominated by the geomagnetic field. Because the rotation of the Earth affects the motion of the plasma, the plasma layer is co-rotating with the Earth. The energetic particles in the magnetosphere rotate and flow around the Earth's axis, forming Annular current . In addition to helical movement along the magnetic field line, charged particles will also produce directional drift under the gradient and curvature of the geomagnetic field, electrons drift east, positive ions drift west, thus forming a ring current. The Van Allen radiation belts It is a two-layer, donut-like radiation region, with the inner layer made up mostly of high-energy protons and electrons, and the outer layer containing heavier ions such as helium. These high-energy particles are trapped by the magnetic field and move in a spiral pattern along the field lines. When... happens Magnetic storm When charged particles deflect from the outer magnetosphere along magnetic field lines into the ionosphere, where they collide with atmospheric atoms, exciting and ionizing them, high latitudes are created aurora . ^[20]

Earth internal heat

Of the heat produced inside the Earth, accretion Residual heat is about 20%, Radioactive decay Heat accounts for 80%. Heat production within the Earth isotope There are mainly potassium-40 , uranium-238 , uranium-235 and thorium-232 . The Earth's core reaches temperatures up to 6,000 °C (10,830 °F) and pressures up to 360 GPa. Because much of the heat comes from radioactive decay, scientists speculate that it was early in Earth's history Half-life period Before the short isotopes were used up, the Earth's internal heat would have been produced more, perhaps twice as much as it is now, 3 billion years ago. So it was extending the radius of the ball Temperature gradient It would have been much larger, and the rate of mantle convection and plate tectonics would have been much faster, possibly creating something like The Komati Rock Such rocks are difficult to form under current geological conditions. ^[21]

The average heat dissipation power density of the Earth surface is 87 mWm 2 - The total heat dissipation power of the entire earth is 4.42×10 13 W. Some of the heat from the core rises up to the Earth's crust through hot lava. This convection is called Mantle plume . So you get hot spots and spills in the mantle basalt . The Earth's heat energy also gradually rises through the mantle in plate tectonics Mid-ocean ridge And drain. Another major way heat is lost is through the lithosphere Heat conduction It mainly occurs at the bottom of the sea, because the bottom of the sea Oceanic crust Thinner than on land. ^[22]

Plate tectonics

Rigid in the outer layers of the earth lithosphere Divided into several plates. These plates are rigid, and the relative motion between plates occurs at three kinds of edges Convergent plate The edge, where the two plates are close to each other; The second is the separating plate margin, where the two plates are separated from each other; The third is the transformational plate margin, where the two plates move sideways against each other. At the edges of these plates, there will be earthquake , Volcanic activity , orogeny And form Oceanic trench . These plates float on asthenosphere On top. ^[23]

As the plates drift, Oceanic plate Dive to Convergent plate Edge below the leading edge. At the same time, mantle material rises to the crust at the edge of the separating plate, producing Mid-ocean ridge . These processes cause the oceanic crust to be continuously produced from the mantle and recycled back into the mantle, so Oceanic crust Most are less than 100 million years old. The oldest present-day oceanic crust is located in the Western Pacific and is estimated to be about 200 million years old. By comparison, the oldest continental crust is about 4.03 billion years old. ^[24]

The main plates of the Earth are Pacific plate , American Plate, Eurasian plate, African plate , Antarctic plate Indian Ocean plate; In addition to Arabian plate , Caribbean plate , Philippine sea plate Off the west coast of North America The Cocos Plate Off the west coast of South America The Nazca Plate And the South Atlantic The Scotia Plate Such plates are more famous. Indo-australian plate Is the Australian plate and Indian plate Formed between 50 and 55 million years ago. Within these plates, Oceanic plate The displacement rate is fast, Continental plate Slow moving: of an oceanic plate The Cocos Plate The displacement rate is 75 mm per year, and the Pacific plate is shifting at a rate of 52 to 69 mm per year; The Eurasian plate, which is a continental plate, moves at an average rate of about 21 millimeters per year.

The earth's surface

The earth Surface area In total, about 510 million square kilometers, about 70.8% of the surface area is covered by water, with most of the crust surface (361.13 million square kilometers) in Sea level The following. The crustal surface of the seafloor has mountainous features, including a global one Mid-ocean ridge System, as well as Submarine volcano Ocean trenches, submarine canyons, submarine plateaus and abyssal plains. The remaining 29.2% (148.94 million square kilometers, or 57.51 million square miles) is not covered by water, including Mountainous region , basin , plain , plateau Such terrain. The surface has been reshaped over a long period of time by tectonics and erosion. Plate tectonics alter the landscape, as do erosion of the surface by winds, precipitation, thermal cycling and chemical processes. Glacial action , coastal erosion, Coral reef The formation, and the impact of large meteorites will have an impact on the reshaping of the landscape. ^[25]

The rocks on the Earth's surface can be roughly divided into three groups according to their origin: Igneous rock , Sedimentary rock and Metamorphic rock . Igneous rock is a rock formed by the cooling and solidification of magma or lava that rises to the surface, also known as igneous rock Magmatic rock Is the main rock that makes up the Earth's crust. Igneous rocks can be roughly divided into two categories according to their origin: one is formed by magma intrusion into the surface Intrusive rock According to the formation of different positions can be divided into Plutonic rock and Hypabyssal rock , common granite It's an intrusive rock. The second is formed by magma erupting from the surface Extrusive rock , also known as Volcanic rock , for example andesite , basalt . The continental crust is mainly composed of low-density granite and andesite, and the oceanic crust is mainly composed of dense basalt. Sedimentary rocks are formed by deposits that are piled up, buried, and tightly bound together. Nearly 75% of the surface of the continent is covered by sedimentary rocks, although they form only about 5% of the crust, metamorphic rocks are a type of rock that is formed by the deterioration of the original rock through high pressure and high temperature environment, such as marble . The most abundant silicate minerals on the Earth's surface are quartz , feldspar , hornblende , mica , pyroxene and olivine Let's wait. Common carbonate minerals are calcite Found in limestone and dolomite ), etc.

The lowest surface is located in Western Asia Dead Sea At an altitude of about -420 meters, Altitude The highest point is at China and Nepal frontier Himalayas the Mount Everest It is more than 8,848 meters above sea level. The average elevation above sea level is 840 m. Traditionally, the Earth's surface has been divided into Seven continents , Four oceans And different seas. It also divides the Earth into poles The southern Hemisphere and The northern hemisphere Two hemispheres, divided by longitude The Eastern Hemisphere and The Western Hemisphere Or roughly according to land and sea distribution Water hemisphere and The continental hemisphere . pedosphere It's the outermost layer of the Earth's land surface, made of soil Is composed of and influenced by soil formation processes. Arable land accounts for 10.9% of the total surface area, of which 1.3% is permanent plowland . Nearly 40% of the earth's surface is used cropland and pasture It includes 1.3×107 square kilometers of farmland and 3.4×107 square kilometers of pasture.

Three rounds

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EDITOR

hydrosphere

In the solar system, the surface is covered by a large area of water is one of the remarkable characteristics of the Earth is different from other planets, Earth's nickname "blue planet" is from this. The Earth's hydrosphere is mainly composed of oceans, but land and sea, lakes, rivers, and groundwater as low as 2,000 meters also account for a certain proportion. The Challenger Deep in the Mariana Trench in the Pacific Ocean is 10,911.4 meters deep, the deepest point in the ocean.

The total mass of the Earth's oceans is about 1.35×10 18 A ton, equivalent to 1/4,400 of the mass of the Earth; The ocean covers an area of 3.618×10 8 Square kilometers, the average depth is 3682 meters, the total volume is about 1.332×10 9 Cubic kilometers. If all the Earth's surfaces were at the same elevation and were a smooth sphere, the average depth of the Earth's oceans would be 2.7 to 2.8 kilometers.

About 97.5% of the Earth's water is seawater 2.5% is Fresh water . Of that 2.5%, 68.7% is fresh water Ice cap or glacier The same form exists. The average salinity of the Earth's oceans is about 3.5%, that is, there are about 35 grams of salt per kilogram of seawater. Much of this salt is produced by volcanic action and cooling of igneous rocks. The ocean is also a reservoir of dissolved atmospheric gases, which are essential for the survival of many aquatic life forms. The ocean is a large reservoir of heat, and its seawater has a significant impact on the global climate. Changes in ocean temperature distribution can have a big impact on weather changes, for example El Nino - Southern Oscillation Phenomenon. earthbound Planetary wind system Among other factors, the Earth's oceans have been relatively stable Ocean current Ocean currents are mainly divided into Warm current and Cold snap The warm current mainly plays a "warming and humidifying" effect on the climate of the nearby area it flows through, and the cold current is vice versa.

biosphere

Due to the existence Earth atmosphere The Earth's hydrosphere and The earth's surface the mineral In this suitable temperature condition on Earth, the formation of suitable for biological survival Natural environment . By living things, people usually mean living objects, including plant , zoon and microorganism . It is estimated that there are about 400,000 species of plants living today, more than 1.1 million species of animals, and at least 100,000 species of microorganisms. According to statistics, there have been about 500 million to 1 billion species of living organisms in geological history, however, in the long evolution of the Earth, most of them have been extinct. Living organisms live in the upper part of the lithosphere, the lower part of the atmosphere, and all of the hydrosphere, forming a unique sphere on Earth called biosphere . The biosphere is a unique circle of all the planets in the solar system that exists only on Earth. ^[26]

atmosphere

The average atmospheric pressure at the Earth's surface is 101.325 kilopascals, Atmospheric elevation It's about 8.5 kilometers. The Earth's atmosphere is 78% nitrogen , 21% Breath Mixed trace amounts steam , Carbon dioxide And other gaseous molecules. The height of the troposphere varies with latitude, located near the equator troposphere The height of the troposphere near the poles is only 8 kilometers, and the height of the troposphere also varies with weather and seasonal factors.

The Earth's biosphere has a significant influence on the Earth's atmosphere. Photosynthesis began to produce oxygen 2.7 billion years ago, eventually forming an atmosphere composed mainly of nitrogen and oxygen. This change allows aerobic organisms to multiply, and then oxygen in the atmosphere is converted into ozone, forming Ozone layer . The ozone layer blocks radiation from the sun Ultraviolet light So that life on Earth could survive. Other important functions of the atmosphere for life include transporting water vapor, providing gases necessary for life, allowing meteoroids to burn up before they hit the ground, and regulating temperature. Certain trace gas molecules in the atmosphere can absorb radiation emitted from the earth's surface Long-wave radiation And thus increase the average temperature of the earth Greenhouse effect . The main greenhouse gases in the atmosphere are water vapor, carbon dioxide, methane And ozone. If there were no greenhouse effect on Earth, the average surface temperature would be only −18°C (currently 14°C), and life would probably not exist. ^[27]

Upper atmosphere

in troposphere The upper, relative upper atmosphere is usually divided into stratosphere , interlayer , thermosphere and exosphere The temperature of each layer varies with the height. The upper stratosphere is the ozone layer, which partly absorbs ultraviolet light from the sun, which is important for life on Earth. This also causes the temperature in the stratosphere to increase with height. The temperature in the middle layer decreases with the increase of height. in thermosphere Due to the strong absorption of short-wave components of solar radiation by gas atoms, the temperature rises sharply with the increase of height. In the upper thermosphere, due to the thin air and high temperature, gas molecules will ionize and form plasma And form the ionosphere. exosphere It extends outward, thinner and thinner, until it reaches the magnetosphere, where the Earth's magnetic field interacts with the solar wind. 100 km above the surface is Karman line In practice, it is thought that the atmosphere and Outer space The boundary of...

On account of Thermal motion Some molecules at the outer edge of the atmosphere can travel fast enough to escape Earth's gravity. This causes a slow but steady loss of atmospheric gases into space. Because free hydrogen has a small molecular weight, it reaches cosmic velocity more easily and escapes to outer space at a faster rate. In terms of hydrogen loss, it is the Earth's atmosphere and surface from early times reducibility Turn into oxidizability One of the reasons. Although photosynthesis also provided some oxygen, the disappearance of reducing agents such as hydrogen is thought to have been necessary for the widespread accumulation of oxygen in the atmosphere, and thus for the emergence of life forms on Earth. Although atmospheric oxygen and hydrogen can be converted to water, most of the loss comes from the destruction of methane in the upper atmosphere. ^[28]

habitability

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EDITOR

climate

The Earth's atmosphere has no definite boundary. The further you get from the surface, the thinner the air gets, and eventually it stops in outer space. Three-quarters of the atmosphere's mass is concentrated in the troposphere, 11 kilometers above the surface. The energy from the sun heats the gases on the surface and in the troposphere above, and the air expands as the heat decreases, causing it to rise, and the cooler, denser gases around it fill in, forming Atmospheric circulation . This redistributes the heat and produces various Weather phenomenon and Climatic condition .

The main atmospheric circulation contains equatorial trade winds below 30° latitude and mid-latitude westerlies between 30° and 60° latitude. Also important in determining climate are ocean currents, particularly those that carry heat from the equatorial seas to the polar regions Thermohaline circulation .

Water vapor from surface evaporation is also transported by atmospheric circulation. if Atmospheric environment Suitable, warm moist air rises, and then the water vapor in it condenses and forms precipitation Fall back to the ground. Most of the precipitation passes through river Systems flow to lower elevations, often returning to the ocean or aggregating lakes Inside. This kind of Water cycle It is an important reason why the earth can sustain life, and it is also a major factor in the erosion of the surface structure over a long geological period. Precipitation varies widely, from a few thousand millimeters a year to less than a millimeter. The average precipitation in a region is determined by atmospheric circulation, geomorphic features and temperature differences.

The amount of solar energy obtained by the Earth's surface decreases with increasing latitude. At high latitudes, the sun hits the ground at a smaller Angle, and the atmosphere through which sunlight must pass is thicker, so the average annual temperature is lower. For every 1 degree increase in latitude, the annual mean temperature at sea level decreases by about 0.4 °C (0.7 °F). The Earth's surface can be divided into several latitudinal zones with roughly similar climates, from the equator to the poles tropics , subtropics , Temperate zone and Polar regions The climate. Different climate types can be defined according to the differences in temperature and precipitation. Commonly used Koppen's climate classification The global climate is divided into five categories: Category A Tropical climate , Category B Arid climate , Category C Temperate climate , Class D cold temperate climate, Class E Polar climate and Alpine climate Each major category is further divided into several subcategories.

Latitude is not a determinant of climate. Because the specific heat of water is greater than that of soil, Marine climates tend to be milder than continental climates. In fact, the Earth is closer to the sun in the southern Hemisphere during summer, resulting in the southern Hemisphere receiving more total radiation throughout the year than the northern hemisphere. Were it not for the larger water area in the Southern Hemisphere, which absorbs the excess radiation, average temperatures in the southern Hemisphere would be 2.3 °C warmer than in the Northern Hemisphere. The effects of atmospheric circulation and ocean currents are equally important. At high latitudes, the climate on the west coast of the continent tends to be milder than that on the interior and east coast of the continent at the same latitude, driven by warm currents and westerly winds. Northern Europe is located in the Arctic Circle, but the climate is more suitable. The lower latitudes of northern Canada and the Russian Far East have cold polar climates instead. In the low latitudes of South America on the west coast, by Peru cold current The impact of summer without heat. In addition, climate is also related to height, the higher the altitude, the colder the climate. ^[29]

temperature

The temperature of the Earth's surface is affected by solar radiation, and the average temperature of the global surface is about 15℃. In the deep underground, where there is no sunlight, the temperature is mainly affected by geothermal heat and increases with depth. At the center of the earth Earth's core The temperature is higher than 6000℃, which is higher than the surface temperature of the solar sphere (5778K, 5500℃). The hottest place on the earth's surface is Basra The highest temperature is 58.8℃. "Northern hemisphere" Cold pole At... East Siberian mountains the Oymyakon The lowest temperature recorded in January 1961 was -71 ° C. The "cold pole" of the world is the Antarctic continent, and in early 1967, the Russians were in Oriental post The lowest temperature ever recorded was -89.2 ° C. 1913 California, USA Death Valley The highest temperature recorded was 56.7 °C (134.1 °F) in Furnace Creek Valley in the National Park. In 1983 in Antarctica Vostok Station Temperatures as low as −94.7 °C (−138.5 °F) have been recorded by remote sensing satellites in eastern Antarctica, although the lowest temperature was −89.2 °C (−128.6 °F). These temperatures have only been measured using modern instruments since the 20th century and may not fully reflect the range of Earth's temperatures. ^[29]

ASSETS

The earth contains all kinds of natural resources for human exploitation. Many of them are like Fossil fuel Of the same kind Non-renewable energy The regeneration rate of these resources is very slow. Fossil fuels are mostly obtained from the Earth's crust, for example coal , petroleum and Natural gas . Humans mainly use these fossil fuels to obtain raw materials for energy and chemical production. Ore Metallogenic processes formed in the Earth's crust, caused by magmatic activity, erosion, and plate tectonics. ^[30]

The Earth's biosphere can produce many biological products of benefit to mankind, including food , Timber , restoratives And can make many organic waste recycling. Terrestrial ecosystems are sustained by topsoil and fresh water, while Marine ecosystems are sustained by dissolved nutrients washed in from the land. In 1980, the world had 5.053 billion hectares (50.53 million square kilometers). Forest land 6.788 billion hectares (67.88 million square kilometers) meadow and pasture And 1,501 million hectares (15.01 million square kilometers) are used plowland . In 1993, 2,481,250 square kilometres (958,020 sq mi) of land was irrigated worldwide. Humans build their dwellings on land using a variety of building materials. ^[31]

disaster

Large areas of the earth's surface are affected Tropical cyclone , typhoon Such as the impact of extreme weather, these disasters affect the survival of life in the affected areas. Between 1980 and 2000, an average of 11,800 people died each year from natural disasters. Between 1900 and 1999, drought precipitant famine Is the most deadly disaster. In addition, mantle convection drives plate movement and causes earthquake and Volcanic activity And other environmental hazards. The Earth's natural and environmental hazards also include Mountain fire , flood , landslip , avalanche Etc., can result in death. Human activities have caused environmental problems in many areas: water pollution, air pollution, acid rain, toxic substances, vegetation destruction (overgrazing, deforestation and deforestation) desertification ), the death of wildlife, species extinction, soil degradation and erosion, and soil erosion. According to the United Nations, carbon dioxide emissions from industrial activities are closely linked to global warming. Projections show that global warming will bring melting glaciers and ice sheets, more extreme temperature ranges, major weather shifts, and rising sea levels to the Earth's environment. ^[32]

Human geography

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EDITOR

World population The total is the number of humans living on Earth at a given time. On the basis of United States Census Bureau The world's population continued to grow after the Industrial Revolution in the 18th century, with the fastest world population growth rate (above 1.8%) occurring in the 1950s. By 2023, there will be about 8 billion people in the world. The world's population is projected to continue to grow, reaching 9.2 billion people by 2050, of whom Developing country Rapid population growth is likely to occur. Population density varies widely around the world, with most people living in Asia. By 2020, 60% of the world's population is expected to live in metropolis In, not village Area.

As of 2015, there are 193 sovereign states in the world The United Nations Member States, in addition to 2 observer States, and 72 dependent and limited recognition States. Asia (48 countries), Europe (44 countries /2 territories), Africa (53 countries /3 territories), Oceania (14 countries /10 territories), North America (23 countries /13 territories), South America (12 countries /1 region). The land surface of the Earth, except for parts of Antarctica, along Danube Some land in the West Bank as well as located Egypt with Sudan Between terra nullius Bill Teweiler All are owned by sovereign and independent states. While there have been nation-states that have attempted to rule the world, no single sovereign government has ever ruled the entire planet. ^[33]

It is estimated that only one in eight places on Earth is suitable for human habitation. Three quarters of it is covered with sea water and one quarter is land. desert (14 per cent), high mountains (27 per cent) and other terrain unsuitable for human habitation make up half of the total land area. locate Canada Nunavut Ellesmere Island Alet (82° 28’n) is the northernmost permanently inhabited place in the world. And located in Antarctica Amundsen-scott Station (90°S) is the southernmost permanent settlement in the world, almost exactly close to the South Pole.

Earth Day

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EDITOR

Earth Day (The World Earth Day) Every year, April 22 is a day dedicated to the world's environmental protection, which aims to raise public awareness of existing environmental issues and mobilize public participation Environmental protection movement Medium, through green Low-carbon life To improve the overall environment of the earth. Earth day Gaylord Nelson and Dennis Hayes It was launched in 1970. Today, Earth Day is celebrated in 192 countries around the world by more than 1 billion people each year, making it the world's largest environmental festival. China Biodiversity Conservation and Green Development Foundation China Green Development Council (CGDC) is a partner organization of Earth Day. ^[36] China Biodiversity Conservation and Green Development Foundation Vice Chairman and Secretary General Zhou Jinfeng "This event can be said to be the beginning of modern environmental activities, it has promoted Western countries Pay attention to Environmental pollution And the problem of destruction is of landmark significance. At the same time, the event took place in 1972 The United Nations The first time Conference on the human environment It has also played a positive role in promoting human beings to fully realize the important connotation of 'only one Earth'." ^[41]

Engineering technical problem

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EDITOR

June 27, 2022, in The 24th Annual Meeting of China Association for Science and Technology At the closing ceremony, China Association for Science and Technology 10 engineering and technology challenges that are critical to engineering and technology innovation are released, including "How to use remote sensing technology to effectively diagnose, identify and evaluate the health of the Earth." ^[37]

Scientific research

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EDITOR

2022 According to a new study published in Nature Geoscience, by analyzing rare diamond inclusions 660 kilometers below the surface, researchers have found a widespread water-saturated environment extending into the lower mantle, which may improve people's understanding of the water cycle deep in the Earth. ^[38]

In November 2022, Harvard University In a paper published in the latest issue of the Astrophysical Journal, astronomers say they have confirmed that the meteor CNEOS 2014-01-08, which entered Earth's atmosphere in 2014, came from another star system and was the first known interstellar visitor to Earth The guest ^[39] .

World record

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EDITOR

Earth has an average density of 5,513 kg/m3 (the planets have the highest density) Guinness World Records ) . ^[40]

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