The ancient astronomer Todmi proposed a theory of what to say around 140 A.D

In the second century A.D., Ptolemy put forward his own theory of the structure of the universe, known as the "geocentric theory". In fact, geocentrism was first coined by Aristotle, who believed that the movement of the universe was driven by God. He said that the universe is a finite sphere, divided into two layers, heaven and earth, and the earth is located in the center of the universe, so the sun and moon orbit the earth, and objects always fall to the ground.

There are 9 equidistant horizons outside the Earth, in order from the inside out: Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, Stellar and Prime Force, and nothing else. Each celestial layer does not move by itself, God pushes the stellar celestial layer, and the stellar celestial layer drives all the celestial strata to move.

The earth, where people live, stands quietly at the center of the universe. Ptolemy fully inherited Aristotle's geocentric theory and wrote the eight-volume Treatise on Greatness, using the data accumulated by his predecessors and his own long-term observations. In the book, he expanded Aristotle's 9 heavens to 11 layers, changed the prime mover heaven to a crystalline heaven, and added the highest heaven and the pure fire heaven to the outside.

Ptolemy conceived that each planet moved around a smaller circumference, and that the center of each circle moved around a circumference centered on the Earth. He called the circle that circles the earth "the chakra," and each small circle "the chakra." At the same time, it is assumed that the earth is not exactly in the center of the average wheel, but deviates from a certain distance, and the average wheel is some eccentric circle; In addition to the above-mentioned orbits, the Sun and Moon planets, together with the stars, also orbit the Earth once a day.

Ptolemy's mathematical picture, which did not reflect the actual structure of the universe, was widely believed as a complete explanation of the observed planetary motions at that time, and achieved practical value for navigation.

Geocentrism says. In fact, it is the culmination of astronomy in the classical period, and the geocentric theory was founded long before it, and his main contribution was to slightly push the earth away from the spherical center of the planet's revolution, so that the model simulation results were very close to the observations, and made a very good fit at that time. And in line with these ideas of the Greco-Roman era, it became the dominant doctrine for more than a thousand years to come.

Ptolemy. Think that the earth is round. The Earth is the center of the universe, and together the celestial bodies move around the Earth.

Ptolemy's System of Universe:

The Ascending Dribble is stationary and at the center of the universe. Each planet and the moon rotate at a uniform speed on the "current wheel", and the center of the wheel revolves around the earth on the "average wheel", and only the noisy finger beam sun directly rotates around the earth on the average wheel. The earth deviates from the center of each wheel at a certain distance.

Mercury. and the center of the current cycle of Venus is always on the Sun-Earth line, which revolves around the Earth once a year; Mars, Jupiter.

Saturn's straight line to the center of their respective cycles is always parallel to the line of the Sun and Earth, and they orbit their respective centers once a year. All stars are located above the outermost solid spherical shell "sidereal sky" and follow the "sidereal day" around the earth once a day; The sun, moon, and planets also move around the earth with the "sidereal sky".

The ancient Greek astronomer Ptolemy came up with the theory of geocentrism about the earth and its motion.

Ptolemy believed that the Earth was stationary at the center of the universe. From the Earth outward, there are the Moon, Mercury, Venus, the Sun, Mars, Jupiter, and Saturn, which orbit the Earth in their respective orbits. Among them, the movement of the planets is more complex than that of the sun and the moon

The planets move on this wheel, which in turn orbits the earth along the average wheel.

Beyond the Sun, Moon, and Planets, there is a celestial sphere stellar sky inlaid with all the stars. Outside, there is the prime mover that moves the celestial bodies. Geocentrism is the world's first model of a planetary system.

Claudius Ptolemaeus, Claudius; Ptolemy (c. 90, Egyptian Ptolemaday 168, Alexandria) was an ancient Greek geographer, astronomer, and mathematician. He was translated as Ptole Mei and Dolu. Long-term astronomical observations.

He wrote extensively throughout his life that he believed that the earth was the center of the universe and that it was stationary, with the sun, moon, planets, and stars moving around it. He was the first scientist in the world to systematically study the composition and movement of the sun, moon and stars. It was revered as the standard work of astronomy until the publication of Copernicus's heliocentric theory in the 16th century, when geocentrism was overturned.

Ptolemy summarized the astronomical achievements of ancient Greece and proposed a complete system of dissipation letters. （）

a.That's right. b.Mistake.

Correct answer to the Nathan source case: a

Personally, I think so: "Ancient Greek astronomy was characterized from the beginning by the search for rational, physical explanations of celestial phenomena. "Yes, his greatest characteristic is rationality, and he wants to explain the celestial phenomena through physics rather than gods as much as possible.

We might as well use our own civilization, ancient Chinese astronomy, to make a comparison. First of all, our model of the universe, such as the Hun Tian Theory, the Gaitian Theory, and the Xuanye Theory, are all relatively general, with few precise quantitative calculations, and more related to philosophy. In contrast, the model of ancient Greek astronomy was based on mathematics and physics for inference and improvement.

For example, our ancestors paid attention to the unity of heaven and man, and the light and shade of the stars in the sky were the judgment of the heavens on the king's government, and if there was any abnormality in the position, it was caused by the erection of rent. This was not the case in ancient Greek astronomy, which hoped to compensate for these errors by revising the theoretical model (because it was determined by quantitative calculations, so there was a basis and feasibility for modification).

Personally, I also have a certain understanding of the astronomy of Arab, Maya and other civilizations, although the astronomy of these civilizations has also reached a high level of achievement, but to a certain extent, it is relatively close to Chinese culture. Arabic astronomy, in particular, originated from Greece and was higher than that of Greece, but an important reason for achieving the glory of the crown was the need of the king (astrology), so it also stagnated in the later period (of course, there were also reasons for social unrest). In contrast, ancient Greek astronomy is indeed unique in terms of rationality.

Claudius Ptolemy.

Ancient Greek astronomer, geographer, and optician.

Representative works: Astronomy Masterpiece, Geography Guide, Four Books.

Ptolemy summarized the achievements of Greek antiquity in astronomy and wrote the thirteen volumes of the Almagest. It determines the duration of the year, compiles a catalog, explains the corrections caused by precession and refraction, and gives the calculation method of the solar and lunar eclipses. He used a large number of observations and research results of Greek astronomers, especially Hipparchus, to systematize various geocentric theories that explain the motion of celestial bodies by eccentric circles or small wheel systems, and later generations gave this geocentric system his name, called the Ptolemaic geocentric system.

The thirteen volumes of the magnum opus Astronomy were the encyclopedia of astronomy at the time, and until Kepler's time, it was a must-read for astronomers. The eight-volume Guide to Geography is an instruction manual for his map of the world, which also discusses astronomical principles. He is also the author of five volumes of Optics, the first of which deals with the relationship between the eye and light, the second on the conditions of virtual visibility and the binocular effect, the third on the reflection of flat and curved mirrors and the size of the sun's visual aperture at noon and in the morning and evening, and the fifth volume attempts to find out the laws of refraction and describes his experiments and discusses the phenomena of atmospheric refraction.

In addition, there are works on chronology and astrology.