solar system

1、The sun is a star, and it is very important for our planet Earth. It gives us light and heat. However, Earth is not alone. It shares the sun with other planets. Together, these planets revolve around the sun in a solar system. Other bodies travel in this solar system, such as moons, asteroids, and c

2、omets. They all move around the sun because the suns gravity is very strong.類地行星水星 Mercury Each planet in our solar system is unique. For example, Mercury is the smallest planet. It has lots of craters, just like our moon.金星 Venus地球 Earth火星 Mars水星是太陽系內(nèi)與地球相似的4顆類地行星之一，有著與地球一樣的巖石個體。它是太陽系中最小的行星，在赤道的半徑是2

3、,439.7公里。水星由大約70%的金屬和30%的硅酸鹽材料組成，水星的密度是5.427克/cm，在太陽系中是第二高的，僅次于地球的5.515克/cm。如果不考慮重力壓縮對物質密度的影響，水星物質的密度將太陽系八大行星及冥王星是最高的未經(jīng)重力壓縮的水星物質密度是5.3克/cm，相較之下的地球物質只有4.4克/cm。從水星的密度可以推測其內(nèi)部結構的詳細資料。地球的高密度，特別是核心的高密度是由重力壓縮所導致的。水星是如此的小，因此它的內(nèi)部不會被強力的擠壓。所以它要有如此高的密度，它的核心必然很大且含有許多的鐵。 金星 中國古人稱金星為“太白太白”或“太白金星”，也稱“啟明”或“長庚” 古希臘人稱

4、為阿佛洛狄忒，是希臘神話中愛與美的女神。而在羅馬神話中愛與美的女神是維納斯，因此金星也稱作維納斯維納斯（Venus）。 科學家推測金星的內(nèi)部構造可能和地球相似，依地球的構造推測，金星地函主要成分以橄欖石及輝石為主的矽酸鹽，以及一層矽酸鹽為主的地殼，中心則是由鐵鎳合金所組成的核心。金星的平均密度為5.24g/cc，次于地球與水星，為八大行星（冥王星已于2006年劃歸為矮行星，故稱八大行星）中第三位的。 structureIron and rock make up most of the four smaller inner planets of our solar system. Gas and

5、 water make up most of the four larger outer planets. This means that you can stand on the surface of the earth, but you cant stand on Saturn. In fact, if you try to stand on Saturn, you would sink down to the core of the planet. 火星Mars is a neighboring planet, and scientist are learning a lot about

6、 it. They send many space probes to Mars. A space probecalled Curiosity landed on Mars on August 6,2012. Curiosity is as big as a car , and it moves over the surface of Mars. It recently found rocks that had strange shapes. Running water made these shapes. This is an important discovery. Space probe

7、s like curiosity continue to explore the planets, moons, and other bodies in our solar system. If technology continues to grow, we will travel to space ourselves.火星火星直徑約是地球的一半，體積為15%，質量為11%，表面積相當于地球陸地面積，密度則比其他三顆類地行星（地球、金星、水星）還要小很多。 以半徑、質量、表面重力來說，火星約介于地球和月球中間：火星直徑約為月球的兩倍、地球的一半;質量約為月球九倍、地球的1/9，表面重力約為月

8、球的2.5倍、地球的2/5?；鹦腔旧鲜巧衬行?，地表沙丘、礫石遍布，沒有穩(wěn)定的液態(tài)水體，以二氧化碳為主的大氣既稀薄又寒冷，沙塵懸浮其中，每年常有塵暴發(fā)生。與地球相比，地質活動不活躍，地表地貌大部份于遠古較活躍的時期形成有密布的隕石坑、火山與峽谷，包括太陽系最高的山：奧林帕斯山和最大的峽谷：水手號峽谷另一個獨特的地形特征是南北半球的明顯差別：南方是古老、充滿隕石坑的高地，北方則是較年輕的平原火星兩極皆有主要以水和冰組成的極冠，而且上面覆蓋的干冰會隨季節(jié)消長。Each planets path around the sun is called an orbit. The planet that

9、are close to the sun have smaller orbits, so they take less time to go around it. Mercury（水星）takes 88 days to complete one orbit. Earth complete one orbit in 365days, or one year. Neptunes (海王星)orbit takes 60,200 days, or almost 165 years.類木行星木星（Jupiter）Jupiter is the biggest planet. Its diameter is

10、 eleven times bigger than earths. 土星（Saturn）Saturn has giant rings of matter around it.天王星（Uranus）海王星（Neptune）Neptune is the farthst from the sun.Drawings of our solar system show the planets close to the sun. However, the distance between the planets and the sun is very far. For example, it would take 176 years to drive a car from earth to the sun. it would take 5300 years to driv