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| Mars the Red Planet |
Mars the fourth plane has a diameter of 6,794 kilometres and it orbits at a distance of 228 million kilometres from the sun. The surface gravity on Mars is 0.38 of the Earth’s gravity and the planet is about one-tenth the size of the Earth. Mars moves at a speed of 24 kilometres per second and takes about 780days to complete one revolution around the Sun.
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One rotation on its own axis is completed in about 24 hours and 37 minutes. It has two moons called Phobos, which is 23 kilometers in diameter and Demos which is 13 kilometres in diameter.
Since it is relatively closer to the Sun as compared to the other outer planets, the surface temperature ranges from –9° to –23° centigrade. In the earlier centuries the astronomers believed that Mars was very much like Earth.
The first photographs of Mars were taken by the Mariner IV spacecraft in the year 1965, subsequently Mariner VIII took some in the year 1971. As a result of these pictures it was discovered that the surface of the planet was red in colour, rocky and dry. In 1976 two unmanned Viking spacecraft were sent to this planet. The data sent back by these spacecraft showed an absence of carbon atoms and living organisms in the atmosphere and soil. From these findings the scientists concluded that there could be no life on Mars and that it was a dead planet.
Mars has a red colour because of two reasons firstly the soil and rocks are largely composed of Iron which has rusted due to exposure to weather thus giving them a reddish appearance, secondly the entire surface is covered with a fine dust which hangs in the air as a result of which the sky tends to have a reddish colour rather than the usual blue. Mars has two polar caps both of which are frozen and covered with ice. Mars also has a number of volcanoes and valleys which indicates that there may have been or there may still be geological activity on this planet.
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