Scientists believe that the formation of the solar system began about five billion years ago. According to the generally accepted existing theory, the Earth and its surrounding planets were formed from cosmic dust located in the vicinity of the Sun. According to the assumptions, the dust particles consisted of iron and nickel atoms, as well as silicates. The gases present near the dust, which formed carbonic organic compounds, were also subject to condensation . Later, nitrogenous substances and hydrocarbons appeared.
The structure of the solar system: hypotheses
A well-known hypothesis of the emergence of our solar system is the electromagnetic theory, which is based on the assumption of scientists that the sun once had a powerful electromagnetic field, and the nebula surrounding the luminary consisted of neutrally charged atoms. As a result of radiation and collisions, the particles were ionized, which fell into traps from magnetic lines of force and were sent after the star. Many years later, the Sun began to lose its moment of rotation, passing it to the cloud of gas from which the planets began to form.
However, this theory is unlikely. In fact, the atoms of light substances should have been ionized closer to the Sun, and heavy metals - further. And the result would be that the planets closest to the star should consist of the lightest chemical elements - helium and hydrogen, and the distant ones - of nickel and iron. However, today you can see the opposite picture.
To get rid of the contradiction, a new hypothesis was created, indicating that the Sun began to nucleate in the bowels of the nebula. The star rotated very quickly, and the nebula gradually became more and more flat until it turned into a disk. After a certain period, it gained acceleration, and the Sun, on the contrary, slowed down. After that, processes began to occur in the disk, as a result of which the formation of the solar system began.
A well-known hypothesis of the origin of planets is the theory of the appearance of the solar system from the cold gas and dust cloud surrounding the sun.
The structure of the solar system: planets
Today it is believed that the solar system consists of a star, the sun and eight planets. According to the physical characteristics of celestial objects can be attributed to two types. One group includes the Earth and planets that have similarities with it - Mars, Venus, Mercury. The second includes such giant planets of the solar system as Neptune, Uranus, Saturn, Jupiter.
Planets are separated according to three characteristics: mass, density and size. The average density of the planets belonging to the terrestrial group is five times higher than the same indicator of giant planets. The structure of the solar system indicates that the objects of the earth group closest to the sun have oxides and heavy compounds of chemical elements: aluminum, magnesium, iron, silicon, and also non-metals. The low density of giants is explained by their structure. They are in a liquid or gaseous state and have the bulk hydrogen or helium.
However, the structure of the solar system shows that any of the giant planets is superior in mass to all the celestial objects of the earth group taken together. All giants have long powerful atmospheres, which are composed of molecular hydrogen, and contain ammonia, methane, helium and water. The remaining substances make up no more than one percent of their mass. By their composition, giant planets are similar to other stars, and first of all - to the Sun.
Atmospheric hydrogen can change from a gaseous form to a liquid form, and even to solid form. The compression of the giants is due to the speed of their rotation around the axis.
Giant planets have many satellites: Jupiter has more than 60, Uranus has 27, Saturn has 62, Neptune has 13, as well as orbital rings, which, according to scientists, are composed of the material of destroyed satellites.
Beyond the giant planets is a relatively small space object - Pluto. It was opened in 1930 and is still not well studied. Until 2006, it was believed that our solar system includes nine planets, and Pluto was the last of them. At present, it is ranked among the dwarf planets.