Heaven in the Eyes of Ancient Chinese People
古人观天
It is said in the ancient times, Gong Gong (a half man and half snake monster) and Zhuan Xu (a god) had a hard fight for control of the heaven, with Zhuan Xu emerging as the victor.Exasperated by failure, Gong Gong went to the northwest corner of the earth and knocked down the Buzhou Mountain,which was one of the eight pillars supporting the sky. As a result, the northwest sky collapsed and the southeast earth sank. Subsequently, the sun, moon, and stars in the sky all slid to the northwest, while the water and silt on the earth flowed to the southeast.
相传在远古时候，共工和颛顼两人为了争夺天下发生了争战。共工失败后，一气之下跑到了大地的西北角，撞倒了那里的不周山。不周山原是八根擎天柱之一，撞倒之后，西北方的天就塌了，东南方的地也陷了下去。于是，天上的日月星辰都滑向西北方，地上的流水泥沙都流向了东南方。
Whenever encountered with natural phenorpena they could not explain, the ancient Chinese people tended to create various legends with their imagination to show their conjectures.The abovementioned is a legend vMdly showing their spec-ulation on the cosmic structure.
当古人对自然现象的成因不能理解时，他们往往会借助想象，创造出各种各样的神话传说，以表达他们对自然界发生的各种现象的揣测。这则神话生动地反映了古人对于天地结构的推测。
The period between the 3rd and 6th centuries witnessed enormous develop-ment in China's astronomy, with the rise of many theories on the cosmic structure.The most important of these were the theory of canopy-heavens, the theonrt of sphere heavens, and the theory of expounding appearance in the night sky.
公元3到6世纪是中国天文学快速发展的时代。在这段时期内，涌现了许多讨论天地结构的学说，其中最重要的是盖天说、浑天说和宣夜说。
The Theory of Canopy-Heavens
盖天说
The oldest theory on cosmic structure, the early school of canopy-heavens claimed that the heaven, shaped like a big pan, covered the earth, shaped like a chessboard.
盖天说是中国最古老的讨论天地结构的体系。早期的盖天说认为：天就像一个扣着的大锅覆盖着棋盘一样的大地。
According to the theory, the sun moves all year round along seven paths,called Qi Heng, and the innermost one was called Nei Heng (Inner Path) , along which the sun moved on the Summer Solstice ( around June 22～ 23).he outer-most one was called Wai Heng ( Outer Path) ,and the sun moved along on the Winter Solstice (around December 22～ 23).During other solar terms, the sun moved along the middle five paths.Advocators of this school also claimed the sun-light could only reach a maximum distance of 167,000 11 (83,500 km) , and noth-ing could be seen beyond. Therefore, they said, the sun moved within the said distance during the day, and beyond during the night.
盖天说认为，太阳在天盖上的周日运动一年中有七条道路，称为“七衡”。最内一道叫“内衡”，夏至日太阳就沿内衡走一圈；最外一圈叫“外衡”，是冬至日太阳的路径；其他节气里，太阳沿中间的五道运行。他们还主张，太阳只能照射16.7万里（83500千米），超过这个距离就什么也看不见了。因此白天就是太阳走到距离我们16.7万里以内的范围，而晚上则在该范围之外。
The Theory of Sphere-Heavens
浑天说
In his book Note to the Arm,illary Sphere , Zhang Heng(78～ 139) , a famous astronomer in the Eastern Han Dynasty,wrote that the heaven was like an egg,with the earth as the yolk inside, and that the heaven wrapped up the earth just as the eggshell did the yolk. This represents a classic elaboration on the theory of sphere-heavens.
东汉著名天文学家张衡(78—139)在《浑天仪注》一文中写道：“浑天如鸡子，天体圆如弹丸。地如鸡子中黄，孤居于内，天大地小……天之包地如壳之裹黄”。天就像一个鸡蛋，大地像其中的蛋黄，天包着地如同蛋壳包着蛋黄一样。这是对浑天说的经典论述之一。
According to the theory, the heaven was higher in the north and lower in thesouth, revoMng around a north-south axis. The east-west axis, vertical to the north-south one, was the heavenly equator. The plane to which the equator is tilt-ed 24。was the ecliptic, and the sun moved along the plane.
浑天说还认为．天球北高南低，通过南北天极的轴旋转。垂直于南北极轴把天球平分成南北两半的大圆就是天赤道。与赤道斜交成大约240角的大圆是黄道，太阳在黄道上运行。
The theory of sphere-heavens played an important part in the history of Chi-nese astronomy, exerting significant influence on the design and manufacture of anaent astronomic instruments, as well as on the explanation of relevant astro-nomic theories.
浑天说在中国天文学史上占有重要的地位，对中国古代天文仪器的设计与制造产生了重大的影响，对天文学的有关理论问题的解释也产生了重大影响。
The Theory of Expounding Appearance in the Night Sky
宣夜说
As a legend goes, during the Warring States Period, a man from the Qi State,having known that the heaven was constituted of gas, in which the moon and stars floated, feared the heaven might collapse one day. Thinking that he would have nowhere to go by then, the man became deeply worried, and lost his appetite.One of his friends brought him to a wise man that helped him to put the things in the right perspective by saying, "The sun, the moon, and the stars are also com-posed of gas. Even if they drop from the heaven, it would mean a collision be-tween gas, and no harm will be caused."
传说战国时期，杞国有一个人听说天是由气体形成的，日月星辰就漂浮其中之后，他非常担心天体会掉下来，让他无处躲藏，于是整日忧心忡忡，茶饭不思。朋友1把他拉到一位智者那里，智者开导他说：“日月星辰也是气体形成的，即使它们掉下来，也是气体落入气体中，不会造成任何损伤。”
In the previously two cosmic theories, the sun, the moon, and the stars all had a shell, meaning there was no reason for them to fall from the heaven.Later,however, the ancient people found the celestial bodies moved freely from one place to another at a fast or slow speed, and sometimes, they might not move atall, hence giving rise to the new theory of expounding appearance in the night sky.
盖天说和浑天说中的日月星辰都有一个可供附着的天壳，都不用担心会掉下来。但是后来人们观测到日月星辰的运动各自不同，有的快、有的慢，有的甚至在一段时间中停滞不前。所以就又产生了一种新的理论“宣夜说”。
The advocators claimed the heaven was composed of boundless gas with no shape.They said the reason that people felt themselves so small was that the heaven was too far away from earth. The celestial bodies floated in the gas with no support, following their own movement rules. The theory broke the boundary ofheaven, exhibiting a boundless universe.
宣夜说主张：天是无边无涯的气体，没有任何形质，我们之所以看天有一种苍苍然的感觉，是因为它离我们太深远了。日月星辰漂浮在空气中，不需要任何依托，因此它们各自遵循自己的运动规律。宣夜说打破了天的边界，为我们展示了一个无边无际的宇宙空间。