英文介绍火星

火星

火星是八大行星之一，按照距离太阳由近及远的次序为第四颗。肉眼看去，火星是一颗引人注目的火红色星，它缓慢地穿行于众星之间，在地球上看，它时而顺行时而逆行，而且亮度也常有变化，最暗时视星等为+1.5，最亮时比天狼星还亮得多，达到-2.9。由于火星荧荧如火，亮度经常变化，位置也不固定，所以中国古代称火星为“荧惑”。而在古罗马神话中，则把火星比喻为身披盔甲浑身是血的战神“玛尔斯”。在希腊神话中，火星同样被看做是战神“阿瑞斯”。有时火星也被称为“红色行星”。

质量 6.421e+23 kg

赤道半径 3,397.2 km

平均密度 3.94 gm/cm3

平均日距 227,940,000 km

自转周期 24.6229 小时

公转周期 686.98 天

赤道地表重力 3.72 m/sec2

赤道逃逸速度 5.02 km/sec

最低地表温度 -140 ℃

平均地表温度 -63 ℃

最高地表温度 20 ℃

大气压力 0.007 bars

大气组成二氧化碳 95.32% 氮 2.7% 氩 1.5% 氧 0.13% 一氧化碳 0.07% 水 0.03% 其他 0.000291%

火星表面的土壤中含有大量氧化铁，由于长期受紫外线的照射，铁就生成了一层红色和黄色的氧化物。夸张一点说，火星就像一个生满了锈的世界。由于火星距离太阳比较远，所接收到的太阳辐射能只有地球的43％，因而地面平均温度大约比地球低30多摄氏度，昼夜温差可达上百摄氏度。在火星赤道附近，最高温度可达20℃左右。火星上也存在大气。其主要成份是二氧化碳，约占95％，还有极少量的一氧化碳和水汽。

火星比地球小，赤道半径为3395公里，是地球的一半，体积不到地球的1/6，质量仅是地球的1/10。火星的内部和地球一样，也有核、幔、壳的结构。

火星的自转和地球十分相似，自转一周为24小时37分22.6秒。火星上的一昼夜比地球上的一昼夜稍长一点。火星公转一周约为687天，火星的一年约等于地球的两年。

火星有两个卫星。靠近火星的一个叫火卫一，较远的一个叫火卫二。由于火星在希腊神话中被看做是战神阿瑞斯，所以天文学家以阿瑞斯的两个儿子——福波斯和德瑞斯命名它的两颗卫星。

火卫一

Phobos

火卫一呈土豆形状，一日围绕火星3圈，距火星平均距离约9378公里。

它是火星的两颗卫星中较大，也是离火星较近的一颗。火卫一与火星之间的距离也是太阳系中所有的卫星与其主星的距离中最短的，从火星表面算起，只有6000千米。它也是太阳系中最小的卫星之一。

在希腊神话中，火卫一是阿瑞斯（火星）和阿芙罗狄蒂（金星）的一个儿子。“phobos”在希腊语中意味着“恐惧”（是“phobia”－恐惧的构词成分）。

火卫一在1877年由Hall发现，1971年由“水手9号”首次拍得照片，并由1977年的“海盗1号”、1988年的“火卫一号”进行观测。

火卫二

Deimos

火卫二是火星的两颗卫星中离火星较远也是较小的一颗，也是太阳系中最小的卫星。

公转轨道: 距火星23,459 千米

卫星直径: 12.6 千米 (15 x 12.2 x 11)

质量: 1.8e15 千克

在希腊神话中，火卫二是阿瑞斯（火星）与阿芙罗狄蒂（金星）的另一个儿子。“deimos”在希腊语中意味着“惊慌”。火卫二在1877年8月10日被Hall发现，在1977年由海盗1号首次拍得其照片。火卫二和火卫一是由像C型小行星那般的富含碳的岩石组成的，并且它们都有很深的地坑。火卫二和火卫一可能是由于小行星的扰动与木星的作用才使它们围着火星运动的。

火星上有明显的四季变化，这是它与地球最主要的相似之处。但除此之外，火星与地球相差就很大了。火星表面是一个荒凉的世界，空气中二氧化碳占了95%。浓厚的二氧化碳大气造成了金星上的高温，但在火星上情况却正好相反。火星大气十分稀薄，密度还不到地球大气的1%，因而根本无法保存热量。这导致火星表面温度极低，很少超过0℃，在夜晚，最低温度则可达到-123℃。

这是美国宇航局海盗号环绕器拍摄的火星全球照片。图中可以清晰地看到巨大的“水手谷”。水手谷长约4000公里，深度约8公里。(USGS)

火星被称为红色的行星，这是因为它表面布满了氧化物，因而呈现出铁锈红色。火星表面的大部分地区都是含有大量的红色氧化物的大沙漠，还有赭色的砾石地和凝固的熔岩流。火星上常常有猛烈的大风，大风扬起沙尘能形成可以覆盖火星全球的特大型沙尘暴。每次沙尘暴可持续数个星期。

Mars

Mars is one of the eight planets, according to the Sun from near and far away from the order of the fourth stars. Looked the naked eye, Mars is an eye-catching fire red stars, which slowly walk through in the trans-pacific, between the Earth's point of view, it is sometimes shun row and retrograde, but also often change the brightness, the most dark, as the magnitude +1.5, the brightest when the much brighter than Sirius has also reached -2.9. As fiery Mars Yingying, brightness constantly changing, the location is not fixed, so that Mars in ancient China as "Ying Huo." In ancient Roman mythology, put the Mars compared to wearing armor was covered in blood of the God of War "Mars." In Greek mythology, Mars also be seen as God of War "Ares." Mars is sometimes also called "Red Planet."

Quality 6.421e +23 kg

Equatorial radius 3,397.2 km

The average density of 3.94 gm/cm3

Average daily distance 227,940,000 km

Rotation cycle of 24.6229 hours

Orbital period 686.98 days

Equatorial surface gravity 3.72 m/sec2

Equatorial escape velocity 5.02 km / sec

Minimum surface temperature -140 ℃

Average surface temperature of -63 ℃

The maximum surface temperature of 20 ℃

Atmospheric Pressure 0.007 bars

Of atmospheric carbon dioxide, 95.32% nitrogen composition of 2.7% Argon 1.5% Oxygen 0.13% Carbon monoxide 0.07% Water 0.03% Others 0.000291%

The surface of Mars soil contains large amounts of iron oxide, due to long term ultraviolet exposure, generating a layer of iron oxide red and yellow. Exaggeration to say that Mars is like a health filled with rusty world. As the distant planet from the sun, the solar radiation received only 43% of the Earth, so Earth's average surface temperature of about less than 30 degrees Celsius, up to hundreds of degrees Celsius temperature difference between day and night. On Mars near the equator, the maximum temperature up to about 20 ℃. There are also the atmosphere on Mars. Its main component is carbon dioxide, accounting for about 95%, there is a very small amount of carbon monoxide and water vapor.

Mars smaller than Earth's equatorial radius of 3395 kilometers, half of the planet, smaller than Earth's 1 / 6, the quality of the Earth is only 1 / 10. Mars, like Earth's interior and, there are core, mantle and shell structure.

To the rotation of Mars and Earth are very similar to the rotation a week for 24 hours 37 minutes 22.6 seconds. A day and night on Mars than on Earth in a slightly longer day and night. Mars revolution is about 687 days a week, Mars year, equivalent to about two years of the Earth.

Mars has two satellites. Near Mars called Phobos, one farther away is called Deimos. As in Greek mythology, Mars was seen as a god of war Ares, so astronomers to Ares two sons - Phobos and Idris named its two satellites.

Phobos

Phobos was a potato shape, on the 1st 3 laps around Mars from the Mars average distance is about 9378 kilometers.

It is the larger of Mars's two satellites, but also from the Mars closer to one. Phobos and Mars is the distance between the satellite and its solar system, all the main stars in the shortest distance from the surface of Mars date, only 6,000 km. It is also one of the solar system's smallest satellite.

In Greek mythology, Phobos is Ares (Mars) and Aphrodite (Venus) and a son. "Phobos" in Greek means "fear" (a "phobia" - fear of word-building components).

Phobos in 1877 by Hall discovered in 1971 by the "Mariner 9" first looks pictures by 1977, "Viking 1", 1988's "Phobos" observations.

Deimos

Deimos is the two satellites of Mars from the Mars is also a smaller one farther away, but also the smallest in the solar system satellites.

Orbits: 23,459 km from Mars

Satellite has a diameter: 12.6 km (15 x 12.2 x 11)

Quality: 1.8e15 kg

In Greek mythology, Deimos is the Ares (Mars) and Aphrodite (Venus) and another son. "Deimos" in Greek means "alarm." Phobos 2 in the August 10, 1877 by Hall discovered in 1977 by Viking 1, the first photograph in the photo. Deimos and Phobos is made of, like C-type asteroid like that of the composition of carbon-rich rocks, and they have a very deep pit. Deimos and Phobos may be due to disturbance of asteroids and Jupiter's role was to make them around Mars movement.

A clear four seasons on Mars change, which is the most important similarities with the Earth. But beyond that, the big difference between Mars and Earth had. The surface of Mars is a desolate world, the air of carbon dioxide accounted for 95%. Thick carbon dioxide atmosphere on Venus caused the high temperature, but on Mars the situation is just the opposite. Martian atmosphere is very thin, density is less than 1% of the Earth's atmosphere and thus unable to save calories. This has led to the Martian surface temperature is very low, rarely more than 0 ℃, at night, the lowest temperature can reach -123 ℃.

It is surrounded by NASA's Viking Mars Global device taken photos. Figure can clearly see the huge "Mariner Valley." Valles Marineris is about 4,000 km, a depth of about 8 km. (USGS)

Mars is known as the red planet, it is because its surface covered with oxide, thus showing a rust red. In most parts of the surface of Mars are rich in red oxide desert, as well as ocher gravel land and solidified lava flows. Mars often have fierce winds, strong winds stirring up the dust can form around the world can cover large Martian dust storms. Each dust storms that last several weeks.