The structure of the Solar system
The planetary system called the Solar, includes a Central luminary – the Sun, as well as many space objects of different size and status. Formed this system by compressing clouds of dust and gas over 4 billion years ago. The main part of the Solar mass of the planet is concentrated in the Sun. Eight major planets revolve around the stars in nearly circular orbits, located within a flat disc.
The inner planets of the Solar system is considered to be mercury, Venus, Earth and Mars (in order of distance from the Sun). These heavenly bodies are referred to the planets of terrestrial group. This is followed by the largest planets, Jupiter and Saturn. Rounding out the series Uranus and Neptune, the furthest located from the center. On the edge of the system rotates the dwarf planet Pluto.
Earth is the third planet of the Solar system. Like other large bodies, it revolves around the Sun in a closed orbit, subject to the gravity of the star. The sun attracts to itself the celestial bodies, not allowing them any closer to the center of the system, nor to fly in the space. With the planets around the sun revolve the smaller bodies – meteors, comets, asteroids.
Features of the planet Earth
The average distance from the Earth to the center of the Solar system is 150 million km from the Location of the third planet was extremely favorable from the point of view of the origin and development of life. The earth receives from the Sun a tiny part of the heat, but this energy is quite sufficient for the limits of the planet could exist organisms. On Venus and Mars, the nearest neighbors of the Land, conditions in this respect are less favorable.
Among the planets the earth the so called Earth stands the highest density and size. Unique is the composition of the local atmosphere that contains free oxygen. The uniqueness of the Ground gives and the availability of powerful hydrosphere. These factors became one of the main conditions for the existence of biological forms. Scientists believe that the formation of the internal structure of the Earth continues through tectonic processes occurring in its interior.
In the vicinity of Earth is the Moon, her natural satellite. This is the only space object, which to date has been people. The average distance between Earth and its satellite is about 380 thousand kilometers of the lunar surface is covered with dust and fragments of rocks. The atmosphere on the Earth's satellite is missing. It is possible that in the distant future, the territory of the moon will be utilized at the earth's civilization.