The planet, very first from the Sun, - Mercury - will be spaced from the earth to space measures absolutely nearby. However on the properties this celestial body considerably differs from the more successful sister's life in the development plan - Earth.
Mercury: both cold, and heat
The planet consists of the substance having high density, at the same time 80% of weight are concluded in an iron kernel. Cover thickness (on Earth it is a cloak plus bark) only 500-600 km. The surface is pitted by craters which were formed from the falling meteorites and as a result of the movement of once young bark. Some signs indicate presence far back in the past of the atmosphere which, however, was more rarefied by 1000 times if to compare to a terrestrial air cover. Due to the lack of the atmosphere the planet on average is heated to +440os in the afternoon, and cools down to minus 110 wasps at night.
Because of the high speed of rotation and a short orbit the year on Mercury lasts only 88 terrestrial days, but merkuriansky day extends for 176 terrestrial. Once was considered that Mercury as the Moon, all the time will be turned to the Sun one party, and only in 1965 it became clear that it not so: the planet makes 1.5 revolutions around own axis. Diameter of this celestial body is more lunar by 1.5 times less terrestrial in 2.5. If to speak terrestrial language, then Mercury is the kingdom of deserts: on the one hand the ice silence covered with the frozen gases with another – the heated stony surface.
Planet researches
This small celestial body is located absolutely near a solar disk which blinds him the light therefore to consider Mercury with the naked eye or in the field-glass it is possible only those days when the planet is on the maximum removal from a star. In the telescope it is well visible that the planet is covered with darkish spots, like lunar "seas". For the first time information on the surface of the planet appeared after the successful travel of the Mariner-10 spacecraft which started from Earth 3.11.1973. In the beginning it was planned to direct the device to Venus, however in its gravitational field Mariner received dispersal and took off from an orbit of Venus straight to Mercury. The device managed to make 3 flights of the planet during which several pictures were made. They showed surprising similarity of a relief of Mercury with the surface of the Moon, at the same time depth of abysses on the celestial body, closest to the Sun, can reach 3 km, and length – 700 km. During the first round (height of 705 km) found magnetic field and shock plasma; also specified body radius – 2439 km and weight. The second flight took place at more considerable distance in 48,000 km. It allowed to establish temperature differences on a surface. The third flight at the height of 318 km confirmed existence of magnetic field (his tension – 1% of terrestrial). Only the western hemisphere underwent a research, east and remained unexplored. "Mariner-10" - the only terrestrial device which flew Mercury.