Is it possible to say with certainty how did the Earth, which it undergoes a metamorphosis and through what stages of development took place?Planet over four and a half billion years, so it does not have reliable information no.Science can offer only theories that are supported by various facts, or finds its logical conclusion.Evidence of the processes occurring in the universe, allows to make assumptions.
all started with a rotation of interstellar cloud, or nebula, which during its movement changed the density due to the effect of gravitational forces on each individual item.As a result of the dust cloud appeared our solar system.This process takes about five billion years ago.
Our planet Earth was inhabited for about three and a half billion years ago, and the time elapsed since then, there have been many changes.The most notable of these were geographical.For example, the lithospheric plates earlier arranged in such a way that many inhabitants of the Earth could freely migrate from North America to Australia.
But back to how Earth appeared.Heavy metal-rock sank deeper into the planet, and hundreds and hundreds of millions of years formed the core.Lighter elements in the form of rocks rocky crust formed on the surface.Compression under the influence of gravity and the release of energy due to radioactive decay of certain chemical compounds leads to more intense heat the interior regions of the Earth.The temperature rose, so the foci of tension began to appear at the junction with the bark.It was in those places where the convection of hot mantle material rings converge at flow upward.
currents forced mantle lithospheric plates are constantly in motion and move relative to each other.They move and now, a year moving to a distance of a centimeter.It is an eye unnoticed, however centimeter, multiplied by billions of years, giving a tangible distance.According to the theory of continental drift, which was first proposed by A. Veneger, Africa and South America were once a single continent.The theory was confirmed in a much more recent studies of the ocean floor.It was also found that before there was Earth in the form in which we know it, the South Magnetic Pole has changed places with the North as much as 16 times.
Not to mention the stages of development of life on the planet, because it was uninhabitable for a very long time after it appeared.The land was initially atmosphere consisting of carbon dioxide, ammonia, methane and hydrogen sulfide.Oxygen in it was not, as a couple of billion years ago there was not even a potential source of gas - photosynthetic organisms.At the beginning of its history, our planet was inhabited by anaerobes.They, of course, produce some oxygen, but all of it went to the oxidation of dissolved gases and compounds.This process was completed by the beginning of the Paleoproterozoic era: all that could already oxidized, and oxygen began to accumulate in the free form.There was a rearrangement of forces: the unit is still aerobic organisms in the biosphere began to dominate, displacing anaerobes.The atmosphere turned into nitrogen and oxygen, and ozone has formed over her screen.Now, cosmic rays can not penetrate to the surface of the planet, typical earlier eras and reduced greenhouse climate has changed dramatically.
before appearing Earth with its continents and continents, land on it is a monolith called the birthplace of scientists and water space is a single ocean of the world.For the first time Rodinia broke up into pieces of about seven hundred and fifty million years ago, and then geography has changed drastically several times.In particular, the thirty million years ago formed the continents that we can see today on the world map.In addition, the scientists suggest that the movement of lithospheric plates lead to a new union of pieces of sushi in a single continent, which have even invented a name - Pangaea Ultima.This will take place presumably in two hundred million years.
