巍峨山峰尽连绵，绿松蒿草覆前川。雾汽抬升循坡上，云海苍茫笼群山。

  The Solar System

  We live in a solar system--a place where planets move in invisible paths, called orbits, around a star in the middle.

  Our star is the Sun. It is the biggest and strongest object in our solar system . Its giant size gives it more gravity, or pull, than anything else.

  Gravity keeps evething around the Sun from floating away. This powerful force holds planets, moons, asteroids, comets, meteors, and more in place. Each has its own special orbit around the Sun.

  Sun

  The Sun is the only star in our solar system. It is a giant ball of hot, glowing gas. Its huge size makes it so powerful that the Sun holds our solar system together.

  The Sun is so bright and hot that it also makes all the light and heat for all the planets in our solar system.

  1.Mercury

  Mercury is the closest planet to the Sun.

  It orbits the Sun in only 88 days. That is faster than any other planet.

  Mercury is hard to see because it is so far away.

  The best times to look for Mercury are before the sun rises or sets.

  As a rocky inner planet, Mercury has a solid surface. 

  During the day , it gets super hot. At night, it gets super cold. Mercury is too hot and too cold for us.

   2.Venus 

  Venus is the second planet from the Sun. Venus spins slowly backwards compared to the other planets. This means that the sun rises in the west and sets in the east.

  It is the hottest planet in our solar system. A layer of thick clouds covers Venus like a blanket, trapping super high heat.

  Sunlight bounces off Venus' clouds. This makes it the brightest planet in our solar system.

  3.Earth 

  Earth is the third planet from the Sun. It is the largest of all the rocky, or terrestrial, planets.

  Earth is also the fifth biggest planet in the solar system.

  Most of Earth is covered with water. There is so much water, Earth looks like a blue marble in outer space.

  Many planets have atmospheres, but only Earth's is safe to breathe.

  Moon--A satellite of the earth

  The moon is smaller than Earth, which gives it less gravity. Gravity holds things down, which gives them weight. This means everything weighs less on the moon. One hundred pounds (45.4kg) on Earth is abount the same as 16 pounds (7.3kg) on the moon.

  There is no air or water on the moon, so there is no weather like rain or snow or wind.

  4.Mars

  Mars is the fourth planet from the Sun. It is a rocky planet like Earth, but much colder because of its thinner atmosphere.

  Mars is nicknamed "The Red Planet" because it is covered in red dust. There is a metal called iron in rocks on Mars. When the iron rusts, it turns red and dusty.

  ( Scientists think Mars is more like Earth than any other planet in our solar system. They believe Mars used to have rivers, and perhaps an ocean, a very long time ago. )

  5.Jupiter

  Jupiter is the fifth planet from the Sun. It is the biggest planet in the solar system.

  Jupiter's surface is an ocean of many different gases and water.

  6.Saturn

  Saturn is the sixth planet from the Sun. It is the second largest planet in our solar system.

  Saturn is best known for its big , bright rings. These rings are made from billions of pieces of ice, dust, and rock that orbit Saturn. Some pieces are as tiny as a speck of dust. A few pieces are as big as mountains. 

  7.Uranus

  Uranus is the seventh planet from the Sun. It looks blue and green from methane gas covering its surface. It is the coldest of all eight planets in our solar system.

  Like Saturn, Uranus has rings. But these rings are not as easy to see because they are much thinner. They are made from billions of pieces of dust.

  8.Neptune

  Neptune is the eighth planet from the Sun. It has wild and windy weather .

  Neptune is a very dark and very , very cold planet.

  Neptune is bright blue because of methane gas in its atmosphere.

  名称的来源：

  1. 水星--Mercury.

  名称来源：在古罗马神话中Mercury是商业，旅行和偷窃之神，即古希腊神话中的赫耳墨斯，为众神传信的神。

  2。 金星--Venus.

   金星(希腊语：阿佛洛狄忒；巴比伦语：Ishtar) 是爱和美的女神，之所以会如此命名，也许是对古代人来说，它是已知行星中最亮的一颗。

  3. 地球--Earth

  名称来源：地球是唯一一个不是从希腊或罗马神话中得到的名字。Earth一词来自于古英语及日耳曼语。在罗马神话中，地球女神叫Tellus--肥沃的土地（希腊语：Gaia, 大地母亲）

  4.火星--Mars

  名称来源：火星（希腊语：阿瑞斯）被称为战神。这或许是由于它红色的颜色；火星有时被称为“红色行星”。

  5.木星--jupiter

  名称来源：木星（a.k.a. Jove; 希腊人称之为宙斯）是上帝之王，奥林匹斯山的统治者和罗马国的保护人，它是Cronus （土星）的儿子。

  6.土星--Saturn.

  名称来源：在罗马神话中，土星（Saturn）“萨图尔努斯”是农神的名称。希腊神话中的农神Cronus和Uranus(天王星) 和盖亚的儿子，也是宙斯（木星）的父亲。土星也是英语中“星期六”（Saturday）的词根。

  7.天王星--Uranus

  名称来源：乌拉诺斯是古希腊神话中的宇宙之神，是最早的至高无上的神。他是盖亚的儿子兼配偶，是Cronus（农神土星），独眼巨人和泰坦（奥林匹斯山神的前辈）的父亲。

  海王星--Neptune.

  名称来源：在古罗马神话中海王星（古希腊神话：波塞冬Poseidon--代表海神）

  ( 40年前，在学地理的时候，书中学到介绍太阳系中的九大行星是：水星（Mercury）, 金星（Venus）, 地球 ( Earth), 火星 ( Mars ), 木星 ( Jupiter ), 土星 ( Saturn ) , 天王星 ( Uranus )  , 海王星 ( Neptune ), 冥王星 ( Pluto ). 后来在一元店买了一本科普书，上面介绍的太阳系是八大行星。为什么呢？于是就去网上查了一下。原来冥王星于2006年时在布拉格举行的第26届国际天文学联会通过决议，冥王星被移出九大行星行列，降级成为矮行星。因为冥王星的质量和体积都在不断的“缩水”，即越变越小。还有冥王星做不到清除轨道附近的其他物体。所以冥王星就被排出了太阳系。自此太阳系只剩八大行星。觉得小科普知识介绍得很好，所以就转摘了下来。）

  希望人类在了解和掌握星球以及地球的知识之后，研究大自然，让地球变得更加美丽。

  ---知识介绍来自科普书《The Solar System》. 而名称的来源介绍来自网络。