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.类地行星水星 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水星是太阳系内与地球相似的4颗类地行星之一，有着与地球一样的岩石个体。它是太阳系中最小的行星，在赤道的半径是2

3、,439.7公里。水星由大约70%的金属和30%的硅酸盐材料组成，水星的密度是5.427克/cm，在太阳系中是第二高的，仅次于地球的5.515克/cm。如果不考虑重力压缩对物质密度的影响，水星物质的密度将太阳系八大行星及冥王星是最高的未经重力压缩的水星物质密度是5.3克/cm，相较之下的地球物质只有4.4克/cm。从水星的密度可以推测其内部结构的详细资料。地球的高密度，特别是核心的高密度是由重力压缩所导致的。水星是如此的小，因此它的内部不会被强力的挤压。所以它要有如此高的密度，它的核心必然很大且含有许多的铁。 金星 中国古人称金星为“太白太白”或“太白金星”，也称“启明”或“长庚” 古希腊人称

4、为阿佛洛狄忒，是希腊神话中爱与美的女神。而在罗马神话中爱与美的女神是维纳斯，因此金星也称作维纳斯维纳斯（Venus）。 科学家推测金星的内部构造可能和地球相似，依地球的构造推测，金星地函主要成分以橄榄石及辉石为主的矽酸盐，以及一层矽酸盐为主的地壳，中心则是由铁镍合金所组成的核心。金星的平均密度为5.24g/cc，次于地球与水星，为八大行星（冥王星已于2006年划归为矮行星，故称八大行星）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.火星火星直径约是地球的一半，体积为15%，质量为11%，表面积相当于地球陆地面积，密度则比其他三颗类地行星（地球、金星、水星）还要小很多。 以半径、质量、表面重力来说，火星约介于地球和月球中间：火星直径约为月球的两倍、地球的一半;质量约为月球九倍、地球的1/9，表面重力约为月

8、球的2.5倍、地球的2/5。火星基本上是沙漠行星，地表沙丘、砾石遍布，没有稳定的液态水体，以二氧化碳为主的大气既稀薄又寒冷，沙尘悬浮其中，每年常有尘暴发生。与地球相比，地质活动不活跃，地表地貌大部份于远古较活跃的时期形成有密布的陨石坑、火山与峡谷，包括太阳系最高的山：奥林帕斯山和最大的峡谷：水手号峡谷另一个独特的地形特征是南北半球的明显差别：南方是古老、充满陨石坑的高地，北方则是较年轻的平原火星两极皆有主要以水和冰组成的极冠，而且上面覆盖的干冰会随季节消长。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.类木行星木星（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