The appearance of the Earth as the planet. The origin of the planet
The issue of the origin of the Earth, the planets and the solar system as a whole worried people since deep antiquity. Myths about the origin of the Earth are traced in many ancient peoples. The Chinese, Egyptians, Sumerians, Greeks had their idea of \u200b\u200bthe formation of the world. At the beginning of our era, their naive ideas were replaced by religious dogmas, not tolerance. In medieval Europe, the truth is attempted sometimes ended in the Kostroma of the Inquisition. The first scientific explanations of the problems are only in the XVIII century. Even now there is no single hypothesis of the origin of the Earth, which gives space for new discoveries and food for an inquisitive mind.
The mythology of the ancients
Man is an inquisitive being. Since ancient times, people differed from animals not only by the desire to survive in the harsh wild world, but also an attempt to understand him. Recognizing the total superiority of the forces of nature over themselves, people began to deify the processes occurring. Most often, it is not the credentials of the world's creation.
Myths about the origin of the Earth in different parts of the planet were significantly different from each other. According to the ideas of the ancient Egyptians, it hatched from a sacred egg, blinded by God with a common clay. According to the beliefs of the island peoples, the earth awaited gods from the ocean.
Chaos theory
The closer to the scientific theory came the ancient Greeks. According to their concepts, the birth of the Earth occurred from the original chaos filled with a mixture of water, land, fire and air. This is joined with the scientific postulates of the theory of the Earth's origin. The rattling mixture of items is chaotically rotated, filling all things. But at some point, the Earth was born from the depths of the firstborn chaos - the goddess Gaya, and her eternal satellite, the sky, - God Uranus. Joint efforts they filled lifeless expanses with a variety of life.
Similar myth formed in China. Chaos Hun-Tun, filled with five elements - wood, metal, earth, fire and water - circled in the shape of an egg on the boundless universe, until the God of Pan-Gua originated in it. Waking up, he discovered around him only lifeless darkness. And this fact has greatly missed him. Having gathered with the forces, the deity of Pan-Gu broke the egg-chaos shell, released two starts: Yin and Yang. Heavy Yin fell down, forming the land, bright and light Yang chemged up, forming the sky.
Class theory of land formation
The origin of the planets, and in particular the Earth, modern scientists are sufficiently studied. But there are a number of fundamental questions (for example, where the water came from), causing hot disputes. Therefore, the science of the universe develops, each new discovery becomes a brick in the foundation of the hypothesis of the Earth's origin.
The famous Soviet scientist is more famous for the polar studies, grouped all the proposed hypotheses and united them into three classes. The first is theories coming from the postulate on the formation of the Sun, planets, moon and comet from a single material (nebula). These are well-known hypotheses of Lotkevich, Laplas, Kanta, Fesenkov, recently recycled by the mine, Sobotovich and other scientists.
The second class combines the views according to which the planets were formed directly from the substance of the Sun. These are the hypotheses of the origin of the Earth of Jeans Scientists, Jeffreys, Multon and Chamberlin, Buffon, and others.
And finally, the third class includes theories that do not combine the sun and the planet with the generality of origin. The most famous Schmidt hypothesis. Let's focus on the characteristics of each class.
Hypothesis Kanta
In 1755, the German philosopher Kant The origin of the Earth briefly described as follows: The initial universe consisted of fixed dust particles of various density. Gravity forces led their movement. It was sticking them to each other (the accretion effect), ultimately leading to the formation of a central red chock - the Sun. Further collisions of the particles led to the rotation of the Sun, and with it and the dust clouds.
In the latter, individual thrickens of substances were gradually formed - embryos of future planets, around which satellites were formed in such a scheme. Educated by the Earth at the beginning of its existence seemed to be cold.
Laplas concept
French astronomer and mathematician P. Laplas proposed a somewhat excellent option explaining the origin of the planet Earth and other planets. The solar system, in his opinion, was formed from a chopped gas nebula with a piece of particles in the center. She rotated and squeezed under the action of global gravity. With further cooling, the speed of rotation of the nebula grew, along the periphery, the rings were peeled from it, which disintegrates on the samples of future planets. The latter at the initial stage was hot gas balls that were gradually cooled and hardening.
Lack of hypothesis of Kant and Laplace
Cant and Laplas hypothesis, explaining the origin of the planet Earth, were dominant in cosmogony until the beginning of the twentieth century. And they played a progressive role, serving the basis of natural sciences, especially geology. The main disadvantage of the hypothesis is the inability to explain the distribution within the solar system of the moment of movement (MKR).
MKP is defined as a product of body mass by distance from the center of the system and the speed of its rotation. Indeed, based on the fact that the sun has more than 90% of the entire mass of the system, it must have a high MKP. In fact, the Sun has only 2% of the general MKR, the planet, especially the giants, are endowed with the rest of 98%.
Theory of Fesenkov
The specified contradiction in 1960 tried to explain the Soviet scientist of Fesenkov. According to his version of the origin of the Earth, the Sun with Planets was formed as a result of the sealing of the Giant Nebula - "Globals". The nebula possessed very sparse matter, composed mainly of hydrogen, helium and a small amount of heavy elements. Under the action of gravity strength in the central part of the globule, star-shaped condensation appeared - the sun. It quickly rotated. As a result of a substance in its surrounding gas-dust medium, ejection of matter was carried out from time to time. This led to the loss of its mass of its mass and the transmission created by the planets a significant part of the MKP. The formation of the planets took place by accretion of the substance of the nebula.
Multon and Chamberlin theories
American researchers Astronomer Moton and Geologist Chamberlin proposed similar hypothesis of the origin of the Earth and the Solar System, according to which the planets were formed from the substance of gas branches of spirals, "elongated" from the sun by an unknown star, which went on a fairly close distance from him.
Scientists were introduced into the cosmogony concept of "Plazinzimal" - these are bunches condensed from the gases of the initial substance that became the embryos of planets and asteroids.
Jeans judgments
English astronomer and physicist D. Jeans (1919) suggested that when with a rapprochement with the sun, another star with the latter broke off a cigar-shaped protrusion, which in the future collapsed into separate clots. Moreover, large planets were formed from the middle thickened part of the "cigar", and in its edges - small.
Schmidt hypothesis
In matters of the theory of the origin of the Earth, Schmidt expressed the original point of view in 1944. This is the so-called meteorite hypothesis, subsequently physico-mathematically substantiated students of the famous scientist. By the way, in the hypothesis, the problem of the formation of the Sun is not considered.
According to the theory, the sun on one of the stages of its development captured (pulled to himself) a cold gas-dust meteorite cloud. Prior to that, it owned very small MKR, the cloud was rotated at considerable speed. In the strengths of the Sun, the differentiation of the meteorite clouds by weight, density and sizes began. Part of the meteorite material fell on the shining, the other, as a result of the accretion processes, formed a bunch-embryo planets and their satellites.
In this hypothesis, the origin and development of the Earth depending on the impact of the "solar wind" - the pressure of solar radiation, which repelled the light gas components to the periphery of the solar system. The land formed in this way was a cold body. Further heating binds to radiogenic heat, gravitational differentiation and other sources of internal energy of the planet. Larger disadvantage of hypothesis, researchers consider a very low probability of the sun capture such a meteorite cloud.
The assumptions of mine and sobotovich
The history of the origin of the Earth still worries scientists. Recently (in 1984) V. Rudnik and E. Sobotovich presented their own version of the planets and the Sun. According to their ideas, the initiator of the processes in the gas-dust nebula could serve as a close explosion of a supernovae. Further events, according to researchers, looked like this:
- Under the influence of the explosion began compressing the nebula and the formation of the central clock - the sun.
- From the emerging Sun, the IRK was transferred by planets with an electromagnetic or turbulent-convective way.
- Giant rings resembling Saturn rings began to form.
- As a result of the accretion of the material of the rings, the planetsimali appeared, subsequently formed into modern planets.
All evolution took place very quickly - for about 600 million years.
Formation of the composition of the Earth
There is a different understanding of the sequence of forming the inner parts of our planet. According to one of them, the protochel was an unsalted conglomerate of iron-silicate substance. In the future, as a result of gravity, it was divided into an iron core and a silicate mantle - the phenomenon of homogeneous accretion. Supporters of heterogeneous accretion believe that the refractory iron core was first accumulated, then more low-melting silicate particles were imposed on it.
Depending on the solution of this issue, we can talk about the degree of initial heating of the Earth. Indeed, immediately after its formation, the planet began to warm up due to joint action of several factors:
- The bombardment of its surface by planezimals, which was accompanied by heat release.
- Isotopes, including short-lived isotopes of aluminum, iodine, plutonium, etc.
- Gravitational subsoil differentiation (if you take homogeneous accretion).
According to a number of researchers, at this early stage of formation of the planet, the external parts could be in a state close to the melt. In the photo of the planet, the Earth would look a hot bowl.
Contracting theory of the formation of continents
One of the first hypotheses of the mainland's origin was a contractual, according to which the pea formation was associated with the cooler of the Earth and the reduction of its radius. It was she who served the foundation of early geological research. At its base, the Austrian geologist E. Zyuss synthesized all the knowledge of the structure of the earth's crust at the same time in the monograph "Lick Earth". But at the end of the XIX century. Data appeared, testifying that in one part of the earth's crust there is a compression, to another - stretching. The contractual theory finally collapsed after the opening of radioactivity and the presence of large reserves of radioactive elements in the Korea.
Drift of the mainland
At the beginning of the twentieth century The hypothesis of the drift of the continents is born. Scientists have long noticed the similarity of the coastal lines of South America and the Arabian Peninsula, Africa and Industan, and others. The first compared the data of Pilligrini (1858), later than Bihanov. The idea of \u200b\u200bthe drift of the mainland was formulated by American geologists by Taylor and Baker (1910) and the German meteorologist and Geophysian Vegener (1912). The latter substantiated this hypothesis in his monograph "The origin of the continents and the oceans", which was published in 1915. Arguments that were brought to protect this hypothesis:
- The similarity of the outlines of the continents on both sides of the Atlantic, as well as the continents, the founding of the Indian Ocean.
- The similarity of the structure on adjacent continents of the Late Paleozoic and Rannienezozoic rocks.
- The fossil remains of animals and plants, which indicate that the ancient flora and the fauna of southern continents have formed a single grouping: especially the fossil remains of dinosaurs of the genus Lorezavrov, found in Africa, India and Antarctica.
- Paleoclimatic data: for example, the presence of traces of the Late Paleozoic coating glaciation.
Formation of the earth's crust
The origin and development of the Earth is inextricably linked with the mountain formation. A. Vegener argued that the mainstream consisting of sufficiently light mineral masses, as it were floating on the underlying severe plastic substance of basalt beds. It is assumed that at first a thin layer of the granite material allegedly covered the whole land. It was gradually the integrity of it was disturbed by the tidal forces of the attraction of the moon and the sun, acting on the surface of the planet from the east to the west, as well as centrifugal forces from the rotation of the Earth, acting from the poles to the equator.
Of the granite (presumably) consisted of a single supermaid pangea. He existed to the middle and collapsed in the Jurassic period. The supporter of this hypothesis of the Earth was a scientist chavis. Then there was a unification of the continents of the Northern Hemisphere - Lavravia, and the union of the mainland of the Southern Hemisphere - Gondwan. Between them were clamped rocks of the Pacific Ocean. Under the least sealed the sea of \u200b\u200bmagma, according to which they moved. Laurels and Gondwan rhythmically moved to the equator, then to the poles. When shifting to the equator, supermasters are fronotally compressed, with flanks pressed on the Pacific Mass. These geological processes, many consider the main factors for the formation of large mountainous massifs. Movement to the equator happened three times: during the Caledonian, Hercinsky and Alpine Gorough formation.
Output
A lot of popular science literature, children's books, specialized publications issued on the formation of the solar system. The origin of the Earth for children in an affordable form is set forth in school textbooks. But if you take a literature of 50 years ago, it can be seen that there are already modern scientists at some problems differently. Cosmology, geology and related sciences do not stand still. Thanks to the conquest of the near-earth space, people already know what seen in the photo Planet Earth from space. New knowledge forms a new idea of \u200b\u200bthe laws of the Universe.
It is obvious that the mighty forces of nature were involved in the creation of the Earth, the mighty forces of nature. It is not surprising that ancient ancestors compared them with the accomplishments of the gods. It is even figuratively impossible to present the origin of the Earth, the pictures of reality would certainly exceed the most courageous fantasies. But the host of knowledge collected by scientists is gradually a holistic picture of the surrounding world is gradually lined up.
In one galaxy there are about 100 billion stars, and there are 100 billion galaxies in our universe. If you were thinking to go on a journey from the ground to the very edge of the Universe, it would take more than 15 billion years old, provided that you will move at the speed of light - 300,000 km per second. But where did the cosmic matter come from? How did the universe originate? The history of the land has about 4.6 billion years. During this time, it arose and died many millions of plants and animals; grew up and treated in dust the highest mountain ranges; Those rushed continuity on the part and ran into different directions, then came across each other, forming new giant sushi arrays. Where do we all know all this? The fact is that, despite all the catastrophes and cataclysms, which is so rich in the history of our planet, surprisingly much of her stormy past is imprinted in rocks that exist and today, in fossils, which are found in them, as well as in the organisms of living beings living on earth these days. Of course, this chronicle is incomplete. We only come across her fragments, the voids are gaping between them, entire chapters fall out of the story, extremely important for understanding what happened in fact. Nevertheless, even in such a trimmed form, the history of our Earth will not give way to fascinating any detective novel.
Astronomers believe that our world arose as a result of a large explosion. Exploding, a giant fireball ranked in the space of matter and energy, which subsequently thickened, forming billions of stars, and those, in turn, united into numerous galaxies.
The Big Bang Theory.
The theory that most modern scientists adheres to, argues that the Universe was formed as a result of the so-called large explosion. An incredibly hot fiery ball, the temperature of which reached billion of degrees, at some point exploded and scattered in all directions of energy flows and particles of matter, giving them a colossal acceleration.
Any substance consists of tiny particles - atoms. Atoms are the smallest material particles that can take part in chemical reactions. However, they, in turn, consist of even smaller, elementary, particles. There are many varieties of atoms that are called chemical elements in the world. Each chemical element includes atoms of certain sizes and weights and differs from other chemical elements. Therefore, during the chemical reactions, each chemical element behaves only in one inherent. All in the universe, from the largest galaxies to the smallest living organisms, consists of chemical elements.
After a big explosion.
Since the fiery ball, scattered apart as a result of a large explosion, had a colossal temperature, tiny particles of matter had at first too much energy and could not connect with each other to form atoms. However, after about a million years, the temperature of the Universe dropped to 4000 "C, and various atoms began to be formed from elementary particles. At first, the easiest chemical elements - helium and hydrogen occurred. Gradually, the universe was cooled and more severe elements were harvested and formed. The process of formation of new atoms and elements It continues to this day in the depths of such stars, like, for example, our sun. Their temperature is extremely high.
The universe cooled. Newly formed atoms gathered in giant clouds of dust and gas. Dust particles faced each other, merged into a single whole. Gravitational forces attracted small objects to larger. As a result, galaxies, stars, planets were formed in the Universe over time.
The land has a molten core, rich in iron and nickel. The earth's crust consists of lighter elements and as it were, it floats on the surface of partially molten rocks forming the land mantle.
Expanding universe.
The big explosion turned out to be so powerful that the whole matter of the universe was scattered at a huge speed on space space. Moreover, the Universe continues to expand to this day. We can confidently assert this because remote galaxies are still postponed from us, and the distances between them are constantly increasing. So, once the galaxies were located much closer to each other than these days.
No one knows exactly how the solar system was formed. The main theory says that the sun and planets were formed from the envious clouds of space gas and dust. More dense parts of this cloud with the help of gravitational forces attracted an increasing amount of substance from the gravitational forces. As a result, the sun arose from it and all his planets.
Microwaves from the past.
Based on the assumption that the universe was formed as a result of a "hot" large explosion, that is, it arose from a giant fiery ball, scientists tried to calculate, to what extent it had to cool to date. They concluded that the temperature of the intergalactic space should be about -270 ° C. The temperature of the Universe scientists determine the intensity of microwave (thermal) radiation, which is from the depths of the cosmos. The measurements confirmed that it actually constitutes about -270 "with.
What is the age of the universe?
To find out the distance to one or another galaxy, the astronomers determine its size, brightness and the color of the light emitted by it. If the theory of a large explosion is correct, then, that means all the existing galaxies now were originally gritted into one super-plate and hot fireball. It is enough for you to divide the distance from one galaxy to the other to the speed, with which they are removed from each other to establish how long ago they constituted a single integer. This will be the age of the universe. Of course, this method does not allow to obtain accurate data, but still it gives reason to believe that the age of the universe is 12 to 20 billion years.
The lava flow follows from the Kilauea Volcano Crater, located on the O-ve Hawaii. When Lava goes to the surface of the Earth, it freezes, forming new rocks.
The formation of the solar system.
The galaxies were formed, in all likelihood, after about 1 - 2 billion years after a large explosion, and the solar system arose about 8 billion years later. After all, the matter was distributed in the space by no means evenly. More dense areas, thanks to the gravitational forces, attracted more and more dust and gas. The dimensions of these areas rapidly increased. They turned into gigantic swirls of dust and gas clouds - the so-called nebula.
One such nebula - namely the solar nebula - thickening, formed our sun. From other parts of the cloud, a bunch of substances occurred, which became planets, including the Earth. They held on their near-air orbits with a powerful gravitational field of the Sun. As the gravitational forces attracted a solar particle closer and closer to each other, the sun became less and more dense. In this case, monstrous pressure occurred in the sunny core. It was transformed into colossal thermal energy, and this, in turn, accelerated the course of thermonuclear reactions inside the Sun. In (a result, new atoms were formed and even more heat was highlighted.
The emergence of conditions for life.
Approximately the same processes, although at a much smaller scale, occurred on Earth. The earth's core was swirling rapidly. Due to nuclear reactions and decay of radioactive elements in the depths of the Earth, so much heat was distinguished that the formulations of its rocks were melted. Lighter substances rich in silicon are similar to glass mineral, they separated in the earth's core from more dense iron and nickel and formed the first earthly bark. After about a billion years, when the Earth cooled significantly, the earth's crust hardened and turned into a strong outer sheath of our planet consisting of solid rocks.
Cooling, the Earth threw many different gases from its core. It usually happened when volcanic eruptions. Light gases, such as hydrogen or helium, mostly disappeared into outer space. However, the force of attraction of the Earth was large enough to keep heavier gases at its surface. They were the basis of the earth's atmosphere. Part of water vapor from the atmosphere was condensed, and oceans arose on Earth. Now our planet was completely ready to become a cradle of life.
Birth and death of rocks.
Ground land is formed by solid rocks, often covered with a layer of soil and vegetation. But where do these rock breeds come from? New rock rocks are formed from a substance that is born deep in the depths of the Earth. In the lower layers of the earth's crust, the temperature is much higher than the surface of the surfaces, and their rock formations are under tremendous pressure. Under the influence of heat and pressure, rock breeds bend and soften, or even melted at all. As soon as in the earth's crust, a weak place is formed, molten rocks - they are called magma - break into the surface of the Earth. Magma follows from the stalls of volcanoes in the form of lava and applies to a large area. Thoroughly, the lava turns into a solid rock.
Explosions and fiery fountains.
In some cases, the birth of rocks is accompanied by ambitious cataclysms, in others it goes quietly and unnoticed. There are many varieties of magma, and different types of rocks are formed. For example, basalt magma is very fluid, easily goes to the surface, spreads wide streams and quickly freezes. Sometimes it breaks out of the vulcan agriculture with a bright "fiery fountain" - this happens when the earth bark does not withstand its pressure.
Other types of magma are much thicker: their density, or consistency, is more like a black molasses. The gases contained in such magma with great difficulty make their way to the surface through its dense mass. Remember how easily air bubbles break out of boiling water and how slowly it happens when you heat something more thick, for example, Kissel. When a more dense magma rises closer to the surface, the pressure on it decreases. Dissolved gases tend to expand, but cannot. When Magma finally breaks out, the gases expand so rapidly that a grand explosion occurs. Lava, wreckage of rocks and ashes scatter in all directions as shells released from guns. Such an eruption happened in 1902 on the O-ve Martinique in the Caribbean. The catastrophic eruption of the volcanic Moptapy Pele completely destroyed the port of Sep-Pierre. About 30,000 people died.
The formation of crystals.
Mountain breeds formed from the cooled lava are called volcanic, or erupted, rocks. While the lava cools, the minerals contained in the molten rocks are gradually converted into solid crystals. If the lava cools fast, the crystals do not have time to grow and remain very small. This happens when the basalt is formed. Sometimes the lava is cooled so quickly that it turns out a smooth glass breed from it, which does not contain crystals, such as obsidian (volcanic glass). A similar, as a rule, it happens during underwater eruption or when small lava particles are thrown out of the vulcan ventilation high in cold air.
Erosion and weathered rocks in Canyon Cydar Breix, Utah, USA. These canyons were formed as a result of the erosion impact of the river, which lasted their channel through the layers of sedimentary rocks, "extruded" up the movements of the earth's crust. The exposed mountain slopes gradually weathered, and the fragments of rocks were formed on them stony scree. In the midst of these shots, protrusions stick out all the solid rocks, which form the edges of the canyons.
Certificate of missing.
The dimensions of the crystals contained in volcanic rocks allow us to judge how quickly the lava cooled and at what distance from the surface of the earth it ran. Before you a piece of granite, as it looks in polarized light under a microscope. Various crystals have different color in this image.
Gneis is a metamorphic rock formation formed from a sedimentary breed under the influence of heat and pressure. A drawing of multi-colored bands that you see on this piece of gneiss, allows you to determine the direction in which the earth's crust, moving, pressed on rock layers. So we get an idea of \u200b\u200bthe events that took place 3.5 billion years ago.
In the rocks and faults (ruptures) in rocks, we can judge in which direction acted with colossal stresses in the earth's crust in the long-lasting geological era. These folds arose as a result of the burning movements of the earth's crust, which began 26 million years ago. In these places, the monstrous forces squeezed the layers of sedimentary rocks - and folds were formed.
Magma does not always reaches the surface of the Earth. It can linger in the lower layers of the earth's crust and then cools much slower, forming amazing major crystals. This is how granite arises. The magnitude of the crystals in some barers allows you to establish how many millions of years ago this breed was formed.
Huduz, Albert Province, Canada. Rain and sand storms destroy soft rocks faster than solid, and as a result, remains (protrusions) with fancy outlines arise.
Sediment "sandwiches".
Not all rocks are similar to volcanic, such as granite or basalt. Many of them consist of a variety of layers and look like a huge stack of sandwiches. They were formed once out of destroyed by the wind, the rains and rivers of other rocks, whose debris was washed into the lake or the sea, and they donkeys on the bottom under the thickness of water. Gradually, such precipitation accumulates a huge amount. They are roughened by each other, forming layers thick hundreds and even thousands of meters. The water of the lake or the sea presses on these sediments with colossal power. Inside them, the water is squeezed out, and they are crushed into a dense mass. At the same time, mineral substances previously dissolved in extruded water, as if cementing all this mass, and as a result, a new rock formation is formed, which is called sediment.
And volcanic, and sedimentary rocks can be pushed up by the movements of the earth's crust, forming new mining systems. Envasional forces participate in the mountain formation. Under their impact, rock rocks are either very hot, or monstrously compress. At the same time, they are transformed - transform: one mineral can turn into another, the crystals are flattened and take another location. As a result, the place of one mountain breed occurs another. Mountain breeds formed during the transformation of other rocks under the influence of the aforementioned forces are called metamorphic.
Nothing forever, even the mountains.
At first glance, nothing can be stronger and more durable than a huge mountain. Alas, it is just an illusion. If it is based on a geological scale of time, where the account goes to millions and even hundreds of millions of years, then the mountains turn out to be as transient as everything else, including us with you.
Any rock, as soon as it starts to be exposed to the atmosphere, will instantly collapse. If you take a look at the fresh chip of the rock or chuck naked, you will see that the newly formed rock surface is often completely different color than the old, who has long spent the air. This is explained by the effect of oxygen contained in the atmosphere, and in many cases - and rainwater. Because of them, various chemical reactions occur on the surface of the rock, gradually changing its properties.
Over time, these reactions lead to the release of minerals, fastening the breed, and it begins to crumble. Crocheted cracks are formed in the breed, in which water penetrates. Freezing, this water expands and breaks the breed from the inside. When the ice is melted, such a breed is simply falling apart in pieces. Very soon, the falling pieces of the breed will melt rain. This process is called erosion.
Glacier Mwer in Alaska. The destructive impact of the glacier and stones frightened in it from the bottom and from the sides, gradually causes the erosion of the walls and the bottom of the valley, on which it is moving. As a result, long stripes of rock fragments are formed on ice - the so-called moraine. When merging two adjacent glaciers, their moraine are connected.
Water-destroyer.
The pieces of the destroyed rock end up in the river. The current drags them on the river bed and becomes them the rock, which forms itself, until the surviving fragments are finally the quiet refractory at the bottom of the lake or the sea. Frozen water (ice) has even greater destructive power. Glaciers and glacier covers of the fiber behind themselves a variety of large and small wreckage of rocks, frozen in their ice sides and bugs. These debris are made deep furrows in the rocks, which are moving glaciers. The glacier can carry the fragments of the rocks that fall on it from above, for many hundreds of kilometers.
Sculptures created by the wind
The wind also destroys rocks. Especially often it happens in the deserts, where the wind transfers millions of smallest grain. Peschins mostly consist of quartz, extremely durable mineral. The whirlwind of the sand strikes the rock, knocking out all new and new grains from them.
Often the wind sticks out sand into large sandy hills, or dunes. Each gust of the wind applies a new layer of sands on the dune. The location of the slopes and the steepness of these sandy hills allow us to judge the direction and strength of the wind, which created them.
Glaciers do deep U-shaped valleys on their way. In Nantefronkone, Wales, the glaciers disappeared even in prehistoric times, leaving behind a wide valley, which is clearly large for a small river flowing through it now. A small lake in the foreground is overclocked by a strip of a particularly durable rock.
It is so nice to realize that the planet Earth turned out to be the most suitable for various forms of life. Here are ideal temperature conditions, enough air, oxygen and safe light. It's hard to believe that there was no choice. Or almost nothing but the molten cosmic mass of an indefinite shape floating under weightlessness. But first things first.
Explosion of an universe scale
Early theories of the origin of the Universe
Scientists have advanced different hypotheses explaining the birth of the Earth. In the 18th century, the French argued that the reason was the cosmic catastrophe as a result of the collision of the Sun with a comet. The British assured that the asteroid compartment pasteing by the luminaries, from which a number of celestial bodies appeared.
German minds advanced further. The prototype of the formation of the planets of the solar system, they considered a cold dust cloud of incredible sizes. Later decided that the dust was hot. One thing is clear: the formation of land is inextricably linked with the formation of all planets and stars that are part of the system of the Sun.
Materials on the topic:
How fast is the earth moving around his axis and the sun?
Today, astronomers and physicists are unanimous in the opinion that the Universe was formed after Big explosion. Billions of years ago, a giant fireball flew into pieces in outer space. This caused a gigantic emission of matter, the particles of which possessed colossal energy. It is the power of the latter prevented the elements to create atoms, forcing me to repel apart from each other. It also contributed to the high temperature (about a billion degrees). But after a million years, the space cooled to approximately 4000º. From this point on, the attraction and formation of atoms of light gaseous substances (hydrogen and helium) began.
Over time, they were grouped into clusters, called nebulae. Such were the prototypes of future celestial bodies. Gradually, the particles inside rotated faster, increasing the temperature and energy, forcing the nebula to shrink. Having reached the critical point, at a certain point, the thermonuclear reaction was launched, which contributes to the formation of the kernel. This bright sun was born.
The appearance of land - from gas to a solid body
The young shine had powerful gravity forces. Their effects caused the formation at different distances of other planets from the clusters of cosmic dust and gases, including the Earth. If you compare the composition of different celestial bodies of the solar system, it will become noticeable that they are not the same.
Materials on the topic:
Why is the land axis inclined?
Mercury mainly consists of metal, the most resistant to the effects of solar luminescence. Venus, land have a rocky surface. And Saturn and Jupiter remain gas giants due to the greatest remoteness. By the way, they protect other planets from meteorites, repaying them from their orbits.
Formation of land
The formation of the Earth began on the same principle that lay at the basis of the appearance of the sun itself. It happened about 4.6 billion years ago. Heavy metals (iron, nickel) as a result of gravity and compression penetrated the center of a young planet, forming a kernel. High temperature created all conditions for a series of nuclear reactions. The separation of mantle and kernel occurred.
Heat release melted and threw light silicon on the surface. He became the prototype of the first bark. As the planet is cooling, the volatile gases broke out from the depths. This was accompanied by volcanic eruptions. The molten lava formed the mining rocks.
Gas mixtures were held at a distance around the Earth by the force of attraction. They amounted to the atmosphere, at first without oxygen. Meetings with ice comets, meteorites led to the emergence of oceans from the condensate of vapors and melted ice. The main students were disconnected, again connected, swimming in a hot mantle. It was repeated many times almost 4 billion years.
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