When you come out early frosty morning outside and feel the crunching underfoot snowflakes or greet the dawn on the river in a hot July, it is very difficult to imagine that once upon a time was nothing like that.Nothing at all: no snow, no river, no grass, not even the sun.There was a boundless space in which particles of dust floated, bumping into each other at tremendous speeds.This period is difficult to somehow call.He did not prehistoric, it some ahistorical: so inconceivably long ago it happened, and so hopeless lifeless space was then ...
However, the origin of the Earth is closely connected with this phase of formation of the universe.Terms and later led to the emergence of our planet began to form from the moment of the Big Bang.Various hypotheses about the origin of the Earth and the birth of the world arose in the minds of people since then, when man first began to think about its place in the universe and that exists beyond his usual territory.
Mythology
All nations have a legend about the origin of the world.They combined the divine underlying mythological creatures.Out of the chaos there are the first deity, which give rise to doubts of supernatural beings, and all that is: the ocean, land, day and night, people.Concepts of origin of the Earth in different nations are often associated with the desire of God to create an expanse between the waters of the world.At different times the myths about the creation of the world supplemented or new versions.For example, in Hinduism, the origins of the Earth and the whole universe is seen in five variants.The basis for the universe, according to various legends, is considered sacred sound Om, first man Purusha, donated part of his body to create the world, the breath of Maha-Vishnu.Also, as the beginning of all things speaks' primary heat "and" cosmic egg. "
cosmogony Slavs
origin of Earth's ancient Slavs, much like other mythological beliefs.Initially, the universe has not been ordered.At that time there was only one God Rod, who structured the primeval chaos.He created the earth connection of the marine and celestial elements.Then his son Svarog began to organize the space.He breathed life into all the earth, and created man first told the people the laws by which to live.
Under the influence of Christianity myth somewhat modified.In the annals of legend about God found floating on the pristine waters by boat and meet the devil.God sends a demon to the bottom of the sea for a handful of sand and built it into terra firma.
name
mythological tales about the world order and related origin of the name "Earth".In thinking ancestors of all modern nations there was no idea of the spherical shape of the planet, and of the planet itself, too.Origin of the name "Earth" is due, on the one hand, with the legend of the plane like a saucer, with a surface of the land and the seas, resting on the backs of giant animals.Different people they were elephants, a turtle or a whale.On the other hand, the origin of the word "land" due to the division of the universe into three levels: the sky, the space inhabited by humans and animals, and the grave, or the underworld.Both these have influenced the emergence of the usual designation of the world in different languages.Origin of the name "Earth" in the ancient Slavs associated with the concepts of "down" and "soil".Earth - is that under the sky, below: the ground beneath their feet, the base.Thus, the origin of the name "Earth" is based on an understanding of the world of men as "flat saucer" and the spaces located below the celestial home of the gods.
In addition, in the culture of our ancestors word "earth" is associated with the whole family, with a familiar territory.Alien and often hostile designated as distant, and his name was similar origin."For the end of the world" - idiom meaning "far away."The ancient Slavs often designated as the kingdom of the dead.
Interestingly, similar to Slavic roots and the importance, from which came the name of the planet in other languages.Thus, the origin of the word "Land» (Earth) in English is also associated with the concept of the bottom and the soil underfoot.
How to get something out of nothing
Naturally, modern scientific ideas about the appearance of the universe are very different from those that form the basis of any religion.Today, all built on the model of the universe Big Bang theory.According to her, about 13.77 billion years ago the universe is the result of hard presentable for its explosive power.The state, in which it remained up to this point is called singular.According to its characteristics, it is so different from anything we know now that even the scientists struggle to understand what processes are taking place in it.
Shortly after the Big Bang, the universe began to expand young.The huge temperature data and the speed of its constituent particles does not allow them to be combined into larger objects.However, as the expansion reduces the temperature.It took about a million years before the universe cooled down to 4000 ° C, and elementary particles began to form atoms.The first appeared helium and hydrogen, formed behind them and the atoms of heavier elements.
In the next stage of development of the universe particles of dust and gas that made up her face and began to form a larger and larger objects.Slowly formed galaxies with stars and planets.The universe continues to expand at the same time, and this process goes so far.
First piece of the Milky Way
Presentation of "The Origin of the Earth" in the classroom often begins with a story about the history of the solar system.It started about 4.6 billion years ago.The appearance of our galaxy piece brought the same processes, which resulted in many parts of the universe were formed.The Milky Way itself appeared about 7-8 billion years earlier.By the formation of the solar system led the gravitational collapse of a relatively small portion of the interstellar molecular clouds.Understanding the processes that occurs at this point of the universe - is quite a difficult task due to their remoteness in time.To judge the events that gave impetus to the formation of the solar system as we know it, is possible only by building a theory based on the study of cosmic or physical laws and correlate their findings with what we actually observe.
«hot" hypothesis
At the end of the XIX century the origin of the Earth and the solar system, astronomers are actively studied Chamberlain T. and F. Multon.They put forward a so-called hot hypothesis.On the creation of the theory pushed their discovery made at the time.It was learned that deep beneath the Earth's surface is literally hellish heat: the temperature reaches 1000 ° C subsoil.
«hot" hypothesis suggests that the Earth, like other planets, originally was a glowing ball, which then gradually became cool.The appearance of these hot clots of matter was explained by the interaction of the sun with the other young, comparable in strength of gravitational attraction, the object.Star took place in relative proximity to our luminary.As a result, between the two formed a kind of bridge, consisting of both the substance of celestial bodies.Gradually the stars dispersed, and the bridge collapsed into separate hot "islets" of matter called planetesimals.They later became the planets and satellites, is now known.
At first it was cold
However, this is not the only theory that explains the origin of the Earth.The hypotheses in the scientific world begin to dominate when due to the large amount of visible facts.In the second half of the last century, astronomers and physicists have turned their attention again to the concept initially cold planets.
nebular theory was first formulated in the XVIII century.Presumably, it expressed Emanuel Swedenborg, Immanuel Kant, and then picked up.The basic hypothesis was the development in the writings of Pierre-Simon Laplace.Stages of the origin of the Earth and the solar system as a whole, according to this theory, line up a little differently than described above, the first of which was the formation of the nebula, or nebula.It was a bunch of gas and dust are concentrated in the collapse of interstellar clouds of molecular site.Nebula, due to exposure to the forces of gravity from adjacent similar formations become rotatable.The nebula of the rotation of the force of gravity appeared, which led to a decrease in its radius.The result was an increase in speed.Young nebula resembled a centrifuge, and its close to the original bowl shape becomes more like an ellipse.After some time, the centrifugal force at the equator trimmed the force of gravity, and the average area of the nebula began to peel off one by one ring.They consisted of all of the same particles of dust and gas, which gradually began to unite into larger objects.Over time, they are "mature enough" to the planets, and the temperature of the new cosmic bodies not allowed to call them hot.
subsoil heat
Today nebular theory is considered the most likely scenario for the formation of the solar system.The development took place with the participation of the hypothesis of many scientific disciplines, some provisions of the Laplace were amended or supplemented.Heat the Earth's interior also received an explanation that does not contradict the theory.
There are two basic reasons for warming up: the radioactive decay and gravitational differentiation of the mineral resources.The first provides about 15% of the heating.The main importance is the separation of elements originally mixed for several layers by gravity.This process has led not only to an increase in the temperature of the subsoil, but also to the formation of the internal structure of the planet, we all study at school: the core, mantle, crust.
young Earth was a ball close to the shape space object consisting of several elements randomly mixed.Recent observations, however, show that the structure of the planet has a fairly ordered structure.The main elements that constitute the Earth - is composed of oxides, oxygen, silicon, iron and aluminum.Each of them thus affects the density of the substance.
Differentiation
mass and volume of the Earth, some in the XVIII century, allowed the scientists to calculate its average density.It was found to be about 5.5 g / cm3.The value of the parameter for the surface - only 2.8 g / cm3.Detected values suggest that the heavier components are concentrated in the center of the globe, and the lungs are surface layers.
Organize items began with the appearance of the planet.Under the influence of gravity iron became "sag" in the center, and an aluminum compound and silicon, on the contrary, "float" on the surface.Iron, changing the place of his position, and shifts the center of gravity of the planet.Due to certain physical laws at the same time, a large amount of heat energy, which leads to heating of the inner layers of the Earth.The amount of energy generated is enormous.At the same time studies show that the planet has never been completely molten.This once again confirms the nebular hypothesis.
Cooling and heating
course, subsoil heat fixed costs for heating the surface, and some of the energy is lost.However, it is successfully compensated by solar radiation.Energy differentiation is used in all the processes taking place in the world: moving continents, mountain formation, volcanism.
Scientists estimate that to date, the process of separating the elements was completed at 85%.After the end of the differentiation of the Earth will be geologically inactive planet, similar in this respect to the Moon.It will happen in about 1.5 billion years.
bombing
addition differentiation of mineral resources and the decay of radioactive elements in the early stages of formation of the Earth, a role in the heating of its inner layers of playing asteroids.Elevated temperatures contributed to frequent clashes small space bodies to the planet.According to one version, the most impressive of these collisions led to the moon.With it collided with the Earth's body the size of Mars.As a result of the planet was knocked out a pretty impressive piece of cloth, which later became a companion.The clash had other results: significantly increased the speed of Earth's rotation axis and tilt it.Also, asteroids and comets are considered one of the possible sources of water.
emergence of life-giving water
origin of water on Earth - is a vast topic.The most likely is today considered a version of its "delivery" asteroids.Indirectly, the data confirm the hypothesis of space research, as a result of which the water has been detected in several small bodies of the solar system.Scientists are leaning towards this version, indicate that the water - quite a volatile substance, but because in the hot conditions of the young Earth, likely to evaporate completely.Hence, the low probability of terrestrial origin of water.Probably so necessary for all living matter on the planet fell to the astroid and comets from the main belt located between Mars and Jupiter.
However, the exact origin of water on Earth - is still a question without a clear answer.It is believed that in the process played a role several factors.Among them, and degassing of magma melted from her volatile elements.Water vapor and some other compounds were thrown on the earth's surface during volcanic eruptions.Then evaporation condensed, so gradually accumulating oceans formed hydrosphere.
appearance of the water, and the problem of the origin of the earth - is not settled until the end of the issue.Probably, his role was played by two processes: the bombing, and degassing of magma.The latter also contributed to the formation of the atmosphere.
origin of life on Earth
Another widely discussed issue related to the history of the Earth - is the emergence of living organisms.Today, there are several hypotheses, which describe the origin of life on Earth.Biology, taught ten years ago, he reveals to his disciples the mystery: life appeared in the waters of the ocean, the so-called primordial soup.Since then, the picture has changed, has acquired new data.
Lesson "The Origin of Life on Earth" begins today with a story about the RNA world.Ribonucleic acid, according to recent studies - the first molecule on a planet with the ability to reproduce.The next step on the way from the inanimate world to the organic was finding boundaries.RNA molecules may in some way being inside hollow spheres which are formed thicker ocean fatty acids.So there was a very simple prototype of the cell: RNA molecule surrounded by a membrane.
Formation metabolism between the external environment and the RNA was made possible by the ability of the latter to attract some and repel other nucleotides.The origin of life on Earth biology and related sciences have not studied until the end.There are still many outstanding issues.Among them, for example, occurrence of division and formation of multicellular organisms.
great symbiosis
less hazy now it considered the history of the emergence of different organelles within the cell.It all started with the appearance of the first organisms capable of phagocytosis, the absorption of nutrients from the environment to form a food vacuole.A new way of eating has led to an increase in cell size: the predator has to be the biggest victims.Hereditary material while stored as genofor precursors chromosomes.They were attached directly to the membrane.Phagocytosis was accompanied by the emergence of strong currents in the cytoplasm, which appeared in the area and genofory.There is a danger of the loss of genetic material, or violation of its structure.As a result, in the cell form a cavity, separated from the cytoplasmic membrane.Gradually, it was transformed into the core.Thus it appeared the first eukaryotic cells.
organelles such as mitochondria and flagella are likely to have arisen in the process of phagocytosis.The predecessors of modern cells, absorbing food, got symbionts, friendly microorganisms.They use the nutrients entering the cytoplasm, began to carry out various functions of the regulation of intracellular processes.According to the concept symbiogenesis thus appeared already in the cell called mitochondria, and flagellum.
