用英文介绍火星

麻烦用英文介绍火星，不要从百度上抄

Mars is the solar system's ninth planet, according to distance from the Sun from near to far order in the fourth. Ancient Chinese Ying Huo said. Mars, the red fire appearance, brightness changes significantly, depending on the magnitude +1.5 to wait in between -2.9 and so on. Satellite 2, from Hall in 1877 Huoxingtaichong found.

Elliptical orbits of Mars orbital plane and the ecliptic is the inclination of 1.9 °, orbital semi-major axis of about 1.524 astronomical units, orbital eccentricity of 0.093. As the eccentricity larger and far away from the Martian day has a difference of 42 million kilometers away, so red on Mars with the Earth's distance greater changes. Mars orbital period of 686.980 days, with an average orbital speed of 24.13 kilometers / second. Mars rotation period is 24 hours 37 minutes 22.6 seconds, the equatorial plane and the surface inclination orbits for the 23 ° 59 '(slightly larger than the Earth), so that on Mars there was a marked change in seasons.

Mars equatorial radius of 3395 kilometers, is 53% of the Earth, volume 15% of the earth mass of 6.42 × 1026 g, 10.8% of the earth, with an average density of 3.96 g / cm 3, the surface gravity for 38% of the earth .

Martian atmosphere is much thinner than the Earth's atmosphere, the main component is carbon dioxide (95%), nitrogen (3%), argon (1-2%), water vapor and oxygen content is extremely low. The Martian surface atmospheric pressure is 7.5 millibars, equivalent to 30-40 km above the Earth's atmospheric pressure. Martian dust storms is a unique phenomenon in the atmosphere, small-scale dust storms occurred frequently. Will occur once each Martian year major dust storms sweeping through the world. In most parts of the surface of Mars was red silicate, hematite and other iron oxide and other metal compounds covered, thus showing a bright orange-red.

Martian surface temperatures above 30 ℃ lower than the Earth day and night temperature difference often Chao Guo 100 ℃. Mars near the equator, the maximum temperature is 20 ℃ or so, the lowest temperature of the polar regions up to -139 ℃. The surface of Mars has many craters, volcanoes and canyons. Northern hemisphere, mainly by a huge volcanic lava plains, and some extinct; the southern hemisphere around the rugged, dotted with craters. There is no liquid water on Mars, but there are thousands of dry river bed, the longest about 1,500 kilometers wide and 60 km, indicating past Mars may have had a lot of liquid water. Mars polar region is covered by a white polar cap. The surface of Mars polar cap is the most significant symbol of its size with the seasons change, in the summer hemisphere polar cap is not the scope, but in the winter hemisphere polar cap may be extended to latitude 60 ° Office. Polar cap of ice and solid carbon dioxide (dry ice), with a temperature between -70 ℃ to -139 ℃, due to constant changes in carbon dioxide with temperature gasification and condensation, making the size of the polar cap is changing. Polar cap, approximately 20% of the preservation of the atmosphere, carbon dioxide, water content than the atmosphere a lot more, if the polar cap in the ice all melted into liquid water formed on the surface of Mars can be a 10-meter-thick water layer. Polar cap in the 17th century by the Dutch physicist Christiaan Huygens discovered.

Mars and the Earth in many ways similar to being surrounded by the atmosphere of the solid surface, there are four seasons and seasonal changes in the delivery of its narrow polar cap in summer, winter and expand, such as ice and snow melting and freezing, the color of the surface of Mars changes with the seasons, such as plant growth and declining in number, the 19th century, observed Mars above the "Canal." Therefore, whether there is life on Mars, or even whether there are higher life forms like people became very interested in the people problem. The 20th century, 60's, Mars probe sends back data to show that the so-called "Mars Canal" is the illusion caused by the human eye, they actually did not exist. Mars surface color with the seasons change is a purely meteorological phenomena,

The surface of Mars is an extremely desolate world, there is no liquid water, the atmosphere is extremely thin, and very cold, is not suitable for life exist. In 1976, the "pirate" 1, 2 probe on Mars in the pre-selected the most promising areas where there is life, a soft landing, collecting the soil samples, soil samples occurred during the experiment some changes, but can not determine the This change is caused by microbial metabolism, or some kind of chemical processes in soil results. Therefore, it can not be completely ruled out on Mars, there is the possibility of lower organisms.