火星
火星是八大行星之一,按照距離太陽由近及遠(yuǎn)的次序?yàn)榈谒念w.肉眼看去,火星是一顆引人注目的火紅色星,它緩慢地穿行于眾星之間,在地球上看,它時(shí)而順行時(shí)而逆行,而且亮度也常有變化,最暗時(shí)視星等為+1.5,最亮?xí)r比天狼星還亮得多,達(dá)到-2.9.由于火星熒熒如火,亮度經(jīng)常變化,位置也不固定,所以中國古代稱火星為“熒惑”.而在古羅馬神話中,則把火星比喻為身披盔甲渾身是血的戰(zhàn)神“瑪爾斯”.在希臘神話中,火星同樣被看做是戰(zhàn)神“阿瑞斯”.有時(shí)火星也被稱為“紅色行星”.
質(zhì)量 6.421e+23 kg
赤道半徑 3,397.2 km
平均密度 3.94 gm/cm3
平均日距 227,940,000 km
自轉(zhuǎn)周期 24.6229 小時(shí)
公轉(zhuǎn)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
最低地表溫度 -140 ℃
平均地表溫度 -63 ℃
最高地表溫度 20 ℃
大氣壓力 0.007 bars
大氣組成 二氧化碳 95.32% 氮 2.7% 氬 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鐵,由于長期受紫外線的照射,鐵就生成了一層紅色和黃色的氧化物.夸張一點(diǎn)說,火星就像一個(gè)生滿了銹的世界.由于火星距離太陽比較遠(yuǎn),所接收到的太陽輻射能只有地球的43％,因而地面平均溫度大約比地球低30多攝氏度,晝夜溫差可達(dá)上百攝氏度.在火星赤道附近,最高溫度可達(dá)20℃左右.火星上也存在大氣.其主要成份是二氧化碳,約占95％,還有極少量的一氧化碳和水汽.
火星比地球小,赤道半徑為3395公里,是地球的一半, 體積不到地球的1/6,質(zhì)量僅是地球的1/10.火星的內(nèi)部和地球一樣,也有核、幔、殼的結(jié)構(gòu).
火星的自轉(zhuǎn)和地球十分相似,自轉(zhuǎn)一周為24小時(shí)37分22.6秒.火星上的一晝夜比地球上的一晝夜稍長一點(diǎn).火星公轉(zhuǎn)一周約為687天,火星的一年約等于地球的兩年.
火星有兩個(gè)衛(wèi)星.靠近火星的一個(gè)叫火衛(wèi)一,較遠(yuǎn)的一個(gè)叫火衛(wèi)二.由于火星在希臘神話中被看做是戰(zhàn)神阿瑞斯,所以天文學(xué)家以阿瑞斯的兩個(gè)兒子——福波斯和德瑞斯命名它的兩顆衛(wèi)星.
火衛(wèi)一
Phobos
火衛(wèi)一呈土豆形狀,一日圍繞火星3圈,距火星平均距離約9378公里.
它是火星的兩顆衛(wèi)星中較大,也是離火星較近的一顆.火衛(wèi)一與火星之間的距離也是太陽系中所有的衛(wèi)星與其主星的距離中最短的,從火星表面算起,只有6000千米.它也是太陽系中最小的衛(wèi)星之一.
在希臘神話中,火衛(wèi)一是阿瑞斯（火星）和阿芙羅狄蒂（金星）的一個(gè)兒子.“phobos”在希臘語中意味著“恐懼”（是“phobia”－恐懼的構(gòu)詞成分）.
火衛(wèi)一在1877年由Hall發(fā)現(xiàn),1971年由“水手9號(hào)”首次拍得照片,并由1977年的“海盜1號(hào)”、1988年的“火衛(wèi)一號(hào)”進(jìn)行觀測.
火衛(wèi)二
Deimos
火衛(wèi)二是火星的兩顆衛(wèi)星中離火星較遠(yuǎn)也是較小的一顆,也是太陽系中最小的衛(wèi)星.
公轉(zhuǎn)軌道: 距火星23,459 千米
衛(wèi)星直徑: 12.6 千米 (15 x 12.2 x 11)
質(zhì)量: 1.8e15 千克
在希臘神話中,火衛(wèi)二是阿瑞斯（火星）與阿芙羅狄蒂（金星）的另一個(gè)兒子.“deimos”在希臘語中意味著“驚慌”.火衛(wèi)二在1877年8月10日被Hall發(fā)現(xiàn),在1977年由海盜1號(hào)首次拍得其照片. 火衛(wèi)二和火衛(wèi)一是由像C型小行星那般的富含碳的巖石組成的,并且它們都有很深的地坑.火衛(wèi)二和火衛(wèi)一可能是由于小行星的擾動(dòng)與木星的作用才使它們圍著火星運(yùn)動(dòng)的.
火星上有明顯的四季變化,這是它與地球最主要的相似之處.但除此之外,火星與地球相差就很大了.火星表面是一個(gè)荒涼的世界,空氣中二氧化碳占了95%.濃厚的二氧化碳大氣造成了金星上的高溫,但在火星上情況卻正好相反.火星大氣十分稀薄,密度還不到地球大氣的1%,因而根本無法保存熱量.這導(dǎo)致火星表面溫度極低,很少超過0℃,在夜晚,最低溫度則可達(dá)到-123℃.
這是美國宇航局海盜號(hào)環(huán)繞器拍攝的火星全球照片.圖中可以清晰地看到巨大的“水手谷”.水手谷長約4000公里,深度約8公里.(USGS)
火星被稱為紅色的行星,這是因?yàn)樗砻娌紳M了氧化物,因而呈現(xiàn)出鐵銹紅色.火星表面的大部分地區(qū)都是含有大量的紅色氧化物的大沙漠,還有赭色的礫石地和凝固的熔巖流.火星上常常有猛烈的大風(fēng),大風(fēng)揚(yáng)起沙塵能形成可以覆蓋火星全球的特大型沙塵暴.每次沙塵暴可持續(xù)數(shù)個(gè)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
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
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.