How did the Earth appear?

Is it possible to say with certainty how the Earth appeared, which metamorphoses underwent it, and through what stages of development did it pass? Planet more than four and a half billion years, so no one has reliable information. Science can offer only theories, which are confirmed by some facts, findings or logical conclusions. Evidence of the processes that took place in the universe allow us to make assumptions.

It all started with the rotation of the interstellar cloud or nebula, which during its movement changed the density due to the action of gravitational forces on each individual element. As a result, our solar system appeared from the gas-dust cloud. This process took place about five billion years ago.

Our planet Earth was inhabited approximately three and a half billion years ago, and during the time that has passed since that time, there have been many changes. The most notable of these were geographical ones. For example, lithospheric plates used to be located in such a way that many inhabitants of the Earth could freely migrate from North America to Australia.

But back to how the Earth appeared. Heavy metal-bearing rocks descended deeper into the planet, and for hundreds and hundreds of millions of years they formed a nucleus. Lighter elements in the form of rocky rocks formed a bark on the surface. Compression under the influence of gravity and the release of energy due to the radioactive decay of certain chemical compounds led to an even stronger heating of the interior regions of the Earth. The temperature grew, so the focus of tension at the junction with the bark began to appear. This happened in those places where the convective rings of the red-hot substance of the mantle converge into a stream directed upward.

The currents of the mantle made the lithospheric plates constantly in motion and shifted relative to each other. They are moving now, moving every year to a distance of a centimeter. This is invisible to the eye, but a centimeter, multiplied by billions of years, gives a tangible distance. According to the theory of continental drift, which was first advanced by A. Veninger, Africa and South America were once a single continent. The theory found its confirmation in much later studies of the ocean floor. It was also found out that before the Earth appeared in the form in which we know it, the Southern Magnetic Pole changed places with the North as much as 16 times.

It is impossible not to mention the stages of the development of life on the planet, because it was uninhabited for a very long time after it appeared. The Earth initially had an atmosphere consisting of carbon dioxide, ammonia, methane and hydrogen sulfide. Oxygen in it was not, because even a couple of billion years ago there were not even potential sources of this gas - photosynthetic organisms. At the beginning of its history, our planet was inhabited by anaerobes. They, of course, produced some oxygen, but all of it was spent on oxidizing gases and dissolved compounds. This process was completed by the beginning of the Paleoproterozoic era: everything that could have already oxidized, and oxygen began to accumulate in a free form. There was a rearrangement of forces: individual so far aerobic organisms began to predominate in the biosphere, replacing anaerobes. The atmosphere turned into a nitrogen-oxygen, and above it formed an ozone screen. Now the cosmic rays could not penetrate to the surface of the planet, the greenhouse effect of the earlier eras diminished and the climate changed greatly.

Before the appearance of the planet Earth with its continents and continents, the land on it was a monolith called the Rodinia, and the water space was a single ocean of Mirovia. For the first time, Rodinia broke up into parts about seven hundred and fifty million years ago, after which the geography changed a few more times. In particular, thirty million years ago, continents were formed, which we can still see on the world map today. In addition, scientists believe that the movement of lithospheric plates will lead to a new union of parts of the land in a single continent, which has even been coined the name - Pangea Ultima. It will happen in two hundred million years.