question of the origin of the Earth, the planets and the solar system as a whole concerned by people since ancient times.Myths about the origin of the Earth can be traced in many ancient peoples.The Chinese, Egyptians, Sumerians, the Greeks had their own idea about the formation of the world.At the beginning of our era of naive representations replaced religious dogma that brooked no argument.In medieval Europe, attempts to find the truth sometimes ended in fires of the Inquisition.The first scientific explanation of the problems relate only to the XVIII century.Even now, there is no unified theory of the origin of the Earth, which gives room for new discoveries and food for the inquisitive mind.
mythology of ancient man - being inquisitive.Since ancient times, humans differ from animals not only by the desire to survive in the harsh world of the wild, but also an attempt to understand it.Recognizing total supremacy over the forces of nature themselves, people began to idolize the processes.The most common inhabitants of heaven is credited with the creation of the world.
myths about the origin of the Earth around the globe were significantly different from each other.According to the ancient Egyptians, she hatched from the eggs of the sacred, the god Khnum sleplennogo of ordinary clay.According to the beliefs of the peoples of the island, the land of the gods fished out of the ocean.
closest to the scientific theory of the ancient Greeks came.In their minds, the birth of the original earth was Chaos, filled with a mixture of water, earth, fire and air.This fits with the scientific postulates of the theory of the origin of the Earth.Mixed elements randomly rotated, filling all things.But at some point, the first-born from the bowels of the earth was born of Chaos - the goddess Gaia, and her eternal companion, sky - god Uranus.Together, they filled the lifeless expanse of diversity of life.
similar myth was generated in China.Chaos Hun-tun, filled with the five elements - wood, metal, earth, fire and water - circling in the form of eggs boundless universe, it is not born a god Pan Gu.Waking, he found around him just lifeless darkness.And this fact greatly saddened him.Gathering his strength, the god Pan Gu faults shell eggs, chaos, releasing two principles: Yin and Yang.The heavy Yin sank down to form the earth, light and easy Yang soared skyward, forming the sky.
class theory of the formation of Earth
origin of the planets, and in particular the Earth, modern scientists studied enough.But there are a number of important issues (for example, where did the water), causing heated debate.Therefore, the science of the universe develops, each new discovery becomes a building block in the foundation of the hypothesis of the origin of the Earth.
famous Soviet scientist Otto Schmidt, best known for polar research, has grouped all the proposed hypotheses and combined them into three classes.The first group includes theories coming from the postulate of the formation of the sun, planets, moons and comets from a single material (nebula).It is known Voitkevich hypothesis, Laplace, Kant Fesenkov recently revised mines, Sobotovich and other scientists.
second class combines the concepts according to which the planets were formed directly from the material sun.This hypothesis of the origin of the Earth scientists Jeans Jeffreys Multona and Chamberlin, Buffon and others.
Finally, the third class includes the theory, combining the Sun and planets common origin.The most famous hypothesis of Schmidt.Let us consider the characteristics of each class.
In 1755 the German philosopher Kant origin of Earth summarized as follows: the original universe consisted of a stationary dust particles of different densities.Gravitational forces have led their movement.There was sticking them on top of each other (the effect of accretion), eventually led to the formation of the central bunch of hot - the sun.Further particle collisions lead to the rotation of the sun, and with it the dust cloud.
In the latter gradually formed some clots of matter - the germs of future planets around such a scheme by which satellites are formed.Thus formed the Earth at the beginning of its existence seemed cold.
French astronomer and mathematician Laplace proposed a somewhat different version, explains the origin of the planet Earth and other planets.The solar system, in his opinion, formed from a hot gaseous nebula with a bunch of particles in the center.She spun and compressed under the influence of gravity.On further cooling, the speed of rotation of the nebula was growing on the periphery of the peeled off her ring, which fell into prototypes of the future planets.Latest in the initial stage were a red-hot balls of gas that gradually cools and solidifies.
disadvantage hypothesis of Kant and Laplace
Kant and Laplace hypotheses explaining the origin of the planet Earth, were dominant in the cosmogony until the early twentieth century.And played a progressive role, serving as the basis for the natural sciences, particularly geology.The main drawback is the inability to explain the hypothesis of distribution within the solar system angular momentum (CDM).
MCR is defined as the product of the mass of the body at a 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 total mass of the system, it must have both high CDM.In fact, Sun has only 2% of CDM same planet, especially the giants are endowed with the remaining 98%.
This contradiction in the 1960s tried to explain Soviet scientist Fesenko.According to his version of the origin of the Earth, the Sun and planets formed by sealing a giant nebula - "globules".The nebula has a very tenuous matter, composed mainly of hydrogen, helium and small amounts of heavier elements.Under the influence of gravity in the central part of the star-shaped globules appeared thickening - the sun.It is a rapidly rotating.As a result of the evolution of solar material into the surrounding gas-dust environment from time to time carried emissions matter.This led to the loss of mass of the Sun and its planets created by the transfer of a significant part of CDM.The formation of the planets held by the accretion of matter nebula.
Theory Multona and Chamberlin
American researchers astronomer Multon and geologist Chamberlin proposed a similar theory of the origin of the Earth and the solar system, according to which the planets were formed from a material gas branches of spirals, "stretched" from the Sun unknown star, which passed close enough to him.
Scientists was introduced in the cosmogony of the concept of "planetesimal" - a clot condensed gases from the initial substances which were the embryos of planets and asteroids.
English astrophysicist J. Jeans (1919) suggested that the approach of another star to the Sun broke the last cigar-shaped protrusion, which later broke up into separate bunches.And from the middle of the thicker portion of the "cigar" large planets formed, and on the edges - small.
In matters of theory of the origin of the Earth an original point of view in 1944 stated Schmidt.This so-called meteoric hypothesis, then physically and mathematically justified disciples of the famous scientist.By the way, the problem of education in the hypothesis of the Sun is not considered.
According to the theory, the sun on one of the stages of its development seizure (pulled him) cold gas and dust cloud of meteoric.Prior to that it owned a very small CDM cloud is rotated at a significant rate.The strong gravitational field of the sun began differentiation meteor cloud mass, density and size.Part of meteoritic material came to light, the other as a result of accretion processes, form clots-germ planets and their satellites.
In this hypothesis, the origin and evolution of the earth, regardless of the impact of "solar wind" - the pressure of solar radiation, which repel light gas components to the periphery of the solar system.Thus formed the Earth was a cold body.Further warming associated with radiogenic heat, gravitational differentiation and other sources of internal energy of the planet.The big drawback of the hypothesis the researchers considered a very low probability of capturing the sun of this meteoric clouds.
Assumptions mines and Sobotovich
The origins of the Earth are still worried scientists.More recently (in 1984) and E. B. Rudnik Sobotovich presented its own version of the origin of the planets and the sun.According to their ideas, initiate processes in the gas-dust cloud could serve as a close supernova explosion.Subsequent events, according to the researchers, looked like:
- Under the influence of the explosion started the compression of the nebula and the formation of the central bunch - the sun.
- emerging from the Sun planets IRAs transmitted electromagnetic or turbulent convection-by.
- began to form a giant ring resembling the rings of Saturn.
- a result of accretion material rings first appeared planetesimals subsequently formed in the modern world.
whole evolution took place very quickly - over 600 million years.
Formation of Earth
There is a different understanding of the sequence of formation of the inner parts of our planet.According to one of them, Proto was a conglomerate of unsorted iron-silicate material.In the future as a result of gravity separation was on an iron core and a silicate mantle - a phenomenon homogeneous accretion.Supporters of heterogeneous accretion believe that the first refractory iron core has accumulated, and then stick to it more fusible silicate particles.
Depending on the solution of this problem we can talk about the extent of the initial warming of the Earth.Indeed, immediately after its formation the planet began to heat up as a result of joint action of several factors:
- bombardment of the surface of planetesimals, which was accompanied by the release of heat.
- decay of radioactive isotopes, including the short-lived isotopes of aluminum, iodine, plutonium, and others.
- gravitational differentiation of mineral resources (if we assume a homogeneous accretion).
According to some researchers, at this early stage of formation of the outer parts of the world might be in a state close to the melt.The photo planet Earth would look like a hot ball.
The contraction theory of the formation of the continents
One of the first hypotheses for the origin of the continents was, contractual, in which the mountain building associated with the cooling of the Earth and the reduction of its radius.That it is the foundation of the early geological studies.On its basis the Austrian geologist E. Suess synthesize all existing at the time knowledge of the structure of the crust in the monograph "The Face of the Earth."But at the end of the XIX century.there is evidence that in one part of the earth's crust is compressed in the other - stretching.Finally, contractual theory collapsed after the discovery of radioactivity and the presence of the Earth's crust in large inventories of radioactive elements.
In the early twentieth century.emerging hypothesis of continental drift.Scientists have noticed similarities coastlines of South America and Africa, Africa and the Arabian Peninsula, the Indian subcontinent and Africa, and others. The first compared the data Pilligrini (1858), later Bihanov.The idea of continental drift was formulated by American geologists Taylor and Baker (1910) and the German geophysicist and meteorologist Wegener (1912).Last substantiate this hypothesis in his monograph "The Origin of Continents and Oceans", which was published in 1915.The arguments cited in favor of this hypothesis:
- similarity outlines of the continents on both sides of the Atlantic, as well as the continents bordering the Indian Ocean.
- similarity of the structure on the adjacent continents and geological sections Late Early Mesozoic rocks.
- fossils of animals and plants, which indicate that the ancient flora and fauna of the southern continents formed a single group: particularly evidenced by the fossilized remains of dinosaurs listrozavrov kind found in Africa, India and Antarctica.
- paleoclimatic data: for example, the presence of traces of Late Paleozoic glaciation.
formation of the Earth's crust
origin and evolution of the earth is inextricably linked to mountain building.Wegener argued that the continents are composed of fairly light mineral masses, as if floating on the underlying substance of their heavy plastic basalt bed.It is assumed that the first thin layer of granitic material supposedly covered the entire Earth.Gradually, his integrity was disrupted by tidal forces of attraction of the Moon and the Sun acting on the surface of the planet from east to west, and the centrifugal forces of the rotation of the Earth, affecting from the poles to the equator.
of granite (allegedly) was a single supercontinent Pangaea.It lasted until the middle of the Mesozoic era, and collapsed in the Jurassic period.Proponents of this theory of the origin of the Earth was a scientist Staub.Then there was the union of the Northern Hemisphere continents - Laurasia, and the union of the continents of the southern hemisphere - Gondwana.Between them they were trapped rock bottom of the Pacific Ocean.Under the continents lies the sea of magma in which they moved.Laurasia and Gondwana moved rhythmically to the equator, then the poles.By moving to the equator supercontinent frontally compressed, thus pushing the Pacific wing mass.These geological processes many consider the main factors of formation of large mountain ranges.Going to the equator happened three times: during the Caledonian, Hercynian and Alpine orogeny.
Conclusion On the topic of the formation of the solar system produced a lot of non-fiction, children's books, specialized publications.The origin of Earth's children in an accessible form set out in textbooks.But if you take the literature 50 years ago, it is clear that some of the problems modern scientists are looking in a different way.Cosmology, geology and related sciences are not standing still.Due to conquer Earth space people already know what is seen in the photo planet Earth from space.New knowledge creates a new understanding of the laws of the universe.
is obvious that the creation of the original chaos of the Earth, the planets and the Sun were involved mighty forces of nature.No wonder that the ancient ancestors to compare them with the achievements of the Gods.Even literally impossible to imagine the origin of the Earth, pictures of reality would certainly have surpassed the wildest fantasies.But the crumbs of knowledge, scientists collected and gradually built up a holistic picture of the world.