"The sky is round and the earth is round" and others
People usually think that the ancient Chinese only knew "the sky is round and the earth is round". In fact, there were three understandings of the universe model in ancient China: the first was the Gaitian theory, the second was the Xuanye theory, and the third was the Huntian theory.
The theory of Gaitian holds that the sky is like a "cover", that is, the shape of a southern hat, with a high center and low surroundings. The earth is like a buckled plate, also with a high center and low surroundings. The cosmological model of "Zhou Bi" is Gaitian theory. "Jin Shu Tianwen Zhi" says: "Below the North Pole is among the heavens and the earth, and the earth is the highest... The sky is higher than the Waiheng, and the winter solstice is 60,000 miles away. The height below the North Pole is 60,000 miles below the Waiheng. The Waiheng is 60,000 miles away. It is 20,000 miles above the North Pole and below the ground. The sky and the earth rise and rise together, and the sun sets and the earth is 80,000 miles away..." "Zhou Bi" applies the Pythagorean theorem in the calculation process of the sundial shadow. The author of "Zhou Bi" believes: "The sky is round like a cover, the ground is like a chess game, the sky turns like a grindstone and goes left, the sun and moon go right, and turn left with the sky, so the sun and moon actually go east, and the sky leads them to the west No." This is the complete expression of the sky is round and the place is round.
The cosmological model recorded in "Yixi Ci" is mainly the Xuan Ye theory. The theory of "Yi" is based on astronomical calculations, but the specific calculation method of Xuan Ye's theory has not been handed down. "Book of Jin Astronomical Chronicles" says that Xuan Ye's book died, but Han secretary Lang Ximeng recorded the theory taught by his predecessor: "The sky has no quality, look up at it, it is infinitely high... The sun, the moon and the stars, naturally Floating in the void, everything needs Qi to move and stop. "Celestial bodies float in space, and "Qi" drives them. Yu Xi of the Jin Dynasty wrote "An Theory of Peace": "The sky is as high as infinity, and the earth is as deep as the unpredictable. The sky is indeed above, with the shape of everlasting peace; the earth is below, with the body of tranquility." He believed that heaven and earth " When they overlap, the squares are all square, the circles are all round, and there is no difference in the meaning of the square and the round." This is to question the unreasonable concept of "the sky is round and the earth is round". Yu Xi's clan ancestor Hejian Xiang Yushu wrote the "Treatise on the Sky" and believed that "the sky is like a dome, like a chicken's chicken, and the sky is connected with the surface of the four seas, floating on the vitality. ...The sun circles around the pole of the celestial body and disappears in the west. Return to the east and do not enter or exit the earth. ...The one under the Dipper should not be in the middle of the earth, but should be in the position of Maoyou of heaven and earth..." Wu Taichang Yao Xin wrote "Xin Tian Lun" and believed that "the body of heaven is lowered to the south. The north is higher. And the winter solstice is extremely low...the summer solstice is when the extreme is rising...when the extreme is standing, the sun is moving in the middle and the earth is shallow, so the night is short; when the sky is high and the earth is high, the day is long; when the extreme is low, the sun is moving in the middle and the earth is deep. , so the night is long; the sky goes away from the earth, so the day is short." At that time, people rejected these statements. However, "Yixi Ci" says, "Heaven is superior and earth is inferior, and the universe is fixed. The humble and the high are established, and the noble is in position. Movement and stillness are constant, and hardness and softness are broken...." It is very similar to "An Tian Lun" and has the same meaning. There are similarities in the wording. There are many statements throughout "Xici" that reflect the views of Xuan Ye theory. For example, "We worship heaven and despise the earth", "We can know the way of day and night, so the gods have no direction and can easily have no body. One yin and one yang is called the way", "When the sun goes, the moon comes, and when the moon goes, the sun comes." , the sun and the moon push each other and the sun comes; when the cold goes, the heat comes, and when the heat goes, the cold comes; the cold and the heat push each other and the years come together." According to these records, it can be seen that the theory of Xuanye has been formed in the Spring and Autumn Period, and did not appear only in the Han Dynasty. By the Han Dynasty, Xuanye said that he had "absolutely no imitation". If "Xici" is indeed from Confucius, then Confucius accepted Xuan Ye's theory.
Huntian theory believes that the sky is like an egg and the earth is like an egg yolk. The sky is big and the earth is small, half of which is underground. Therefore, the twenty-eight constellations are half hidden and half visible, and the sky rotates like a wheel. Zhang Heng of the Eastern Han Dynasty made an armillary sphere to demonstrate that the celestial phenomena were completely consistent with the real starry sky. The principles of Hun Tian are wonderful, but scholars are doubtful about them. King Zhongren of the Han Dynasty refuted the armillary sphere based on the theory of Gaitian, saying: "In the old days, it was said that the sky rotates through the ground. Nowadays, there is water every ten feet of the ground. How can the sky move through the water? This is not the case. The sun rotates with the sky and does not enter. The earth... is regarded as the sun entering, not entering, and far away. When the sun enters the west, the people below it will also call it the middle. People in the four directions will refer to the one who is close to it and the one who is far away. Come on..." Its point of view can be proved by observing the torch in the distance. This understanding actually means that "the earth is round." Those who study ancient history often make subjectivist mistakes in the location of "Yutani", that is, they fail to realize that the place where the sun rises and sets is relative and not unique. However, Tanggu and Yugu in ancient China were specific concepts for the Chinese ancestors. They became specific places and were no longer common terms.
Among the three theories, the Gaitian theory has the existence of magic numbers, which has made a contribution to the development of mathematics, but "tests the state of heaven, and many things are violated." Xuanye theory only preserved some theories, but "Book of Changes·Xici" preserved its theories, which has value in cultural history.
The armillary sphere is said to be "subtle and profound, and has been difficult to learn for hundreds of generations." The armillary sphere is also convincing, but "the official has his own tools but no book." Only the theory of Gaitian includes the view that "the sky is round and the earth is round". The theory of Huntian explains that the earth is oval and wrapped by the sky - this statement is close to the truth.
"The Classic of Mountains and Seas·Haiwai Nan Jing": "What is contained in the earth is between the Liuhe and the four seas. It is illuminated by the sun and the moon, it is passed by the stars, it is recorded by the four seasons, and it is measured by Tai Sui. "Born by the gods, the objects have different shapes and may die young or live long, but only the sage can understand them." There are exactly the same words and sentences at the beginning of "Huainanzi Terrain". "Huainanzi·Shi Ze" states that the distance between east and west, north and south of the earth, and the height of the sky are all techniques of "Zhou Bi". The opinions of the three schools recorded in "Book of Jin" can provide a general understanding of the three theories, but they are not necessarily authentic. In ancient times, the geocentric theory was a taken-for-granted concept. Ancient Chinese cosmology showed the coexistence of different theories, which reflected the exploration spirit of our ancestors.
The view at the beginning of the sixth chapter of "The Classic of Mountains and Seas" and the "Overseas Classic", "Haineijing" (four chapters), and "Dahuang Jing" is that the earth is square, while the ninth-century Joseon Dynasty's "Under the World" "Map", the Earth is drawn as a circle, indicating that some people at that time had already determined that the Earth was round. The content is related, but the form is different. The two have the same geographical knowledge, but the cosmology is opposite. There should be one of them that is not authentic.