November 22, 1971 (, Xinhai October fifth day), the human "messenger" for the first time to reach Mars.

Mars is one of the solar system, the nine planets, according to the order of the distance of the sun and fourth teeth. With the average distance of the sun is 1.52 astronomical units, or 227,940,000 km. Equatorial diameter is 53% of the Earth's, the quality of Earth 11%, the density is 3.9 times that of water, the orbital period 687 days, the rotation period of 24 hours 37 minutes. On Mars has seasons six long months, on a quarterly basis. The surface of Mars, unlike the moon as densely covered with craters, more like rocks on Earth, volcanoes and desert areas. Much like the Earth due to its surface, in the past people have always thought that Mars is a planet of the solar system most likely to have life. There are even many science fiction novels, there have been a "Martian". What Mars people? This is the people have a secret desire to know.
1971 11 22, the Soviet unmanned spacecraft "Mars" sent a lander on Mars, this is the first human sent to this planet "messenger & rdquo ;. After that, the United States also sent to Mars this "messenger". From the messages returned by the Soviet Union, the U.S. spacecraft sent to Mars in the past few years on Mars, Martian, even traces of life have not been found. Mars is a barren, lonely wilderness, covered with sand dunes, rocks, climate as dry as a desert, but also much colder than Antarctica. The average temperature of the surface of Mars to minus 23 degrees Celsius, the coldest place in the low to minus 137 degrees Celsius. The atmosphere on Mars is essentially carbon dioxide. However, the scientists also found that, in some places on Mars steam more, many organisms on Earth can survive under these conditions. So, now can not be absolutely sure that there is no possibility of the existence of life on Mars.
Mars has two moons, called Phobos. One near the Martian, the average distance of about 9400 km; Second farther away from the Mars, the average distance of about 23,500 kilometers. Rotation cycle around Mars were 7:39 and 30 hours 30 minutes. (Lsjt.org)