In the 3rd century BC, the concept of spherical earth appeared, but after all, there was no direct evidence, so people did not form a * * * knowledge about it. Until 15 19 ~ 1522, the fleet led by Portuguese Magellan completed the round-the-world voyage, further confirming that the earth is indeed a sphere. Since then, people have called the "Earth" where we live "Earth". The realization of Magellan's voyage around the world is a milestone for mankind to finally prove that the earth is a big ball. The best gift given to the navigators by the Spanish king at that time was a globe, which was a model of colorful earth owned by human beings but not really recognized by people. It is engraved with a meaningful inscription-"You hugged me first".
The earth is spherical. In the16th century, there is nothing to argue about. But human understanding of the shape of the earth is not over. What kind of sphere is the earth? Is it a * * * body or an ellipsoid, a flat sphere or a long sphere, regular or irregular?
Newton, a famous British physicist, put forward the law of universal gravitation in the 1980s. Based on this theory, he proposed that the earth can't be a regular sphere, because it rotates around its own axis, but can only be a flat sphere with polar compression and equatorial uplift, like an orange. In other words, the radius of the earth becomes shorter with the increase of latitude, the radius of the equator is the longest and the radius of the pole is the shortest. When the French astronomer Richard observed astronomy in South America, he found that the pendulum clock only oscillated under the action of ground gravity, and the period of oscillation in Paris, France was different from that in South America. He thought it was caused by the difference of ground gravity, and then explained the change of ground gravity. His speculation is completely consistent with Newton's theory, and Richir formally put forward his own conclusion. However, the authority of the Paris Academy of Sciences at that time could not accept the objective fact that the ground gravity would change. In The Shape of the Earth, the representatives who opposed Newton's theory were Cassini and his son, who was the first director of the Paris Observatory under the Paris Academy of Sciences at that time. They made a very inaccurate arc measurement of the meridian between Paris and the northern city of Dunkirk. Their measurement results are completely contrary to Richir's conclusion. So Voltaire said in his article: "The shape of the earth is considered as an orange in London, but it is imagined as a watermelon in Paris."
In the 1930s from 65438 to 2008, the debate about flat land and long land became more and more intense. The French Academy of Sciences in Paris is divided into two factions, and those who theoretically support Newton's flat ball theory form a powerful force in the institute. In order to solve this dispute, King Louis XIV of France sent two expeditions to measure the radian of meridian again. One team went to Lapland at 66 degrees north latitude, and the other team crossed the ocean to Peru in South America (2 degrees south latitude). This is a great feat in the history of science in18th century. The South American expedition returned to Paris after working for 10 years. As soon as this precise meridian measurement result was published, it caused a sensation in the Paris Academy of Sciences and the whole scientific community, because they proved that Newton's flat ball theory was completely correct with facts. For this reason, Voltaire wrote humorously that the two expeditions "finally suppressed the poles together with Cassini" with the most eloquent facts.
It should be said that Eratosthenes, a Greek geographer in the 3rd century BC, was the first to calculate the size of the earth. He successfully measured the meridian length between Aswan and Alexandria by triangulation, and calculated that the circumference of the earth was about 250,000 Greek miles (39,600 kilometers), only 340 kilometers away from the actual length, which was really remarkable more than 2,000 years ago.
Since 1950s, the rapid development of science and technology has opened up many avenues for geodesy. High-precision microwave ranging, laser ranging, especially satellite launch, coupled with the application of computers and international cooperation, enable people to accurately measure the size and shape of the earth. Through actual measurement and analysis, the exact data are finally obtained: the average equatorial radius of the earth is 6738. 14 km, the polar radius is 6356.76 km, and the equatorial perimeter and meridian perimeter are 40075 km and 3994 1 km respectively. The survey also found that the North Pole is about 18.9 meters high and the South Pole is 24 ~ 30 meters low. It seems that the earth is shaped like a pear: its equatorial part protrudes, which is its "pear body"; The North Pole is a bit sharp, like "pear pedicle"; The South Pole is a little concave, like a "pear navel", and the whole earth is like a pear-shaped rotating body, so people call it a "pear-shaped earth". To be exact, the earth is a triaxial ellipsoid.
1. What have you learned from people's understanding of the shape of the earth? ..... What have you learned from people's understanding of the shape of the earth?
A: I realize that if human society wants to develop and progress normally, it must learn tolerance and scientific freedom. The argument that the earth is round has been discriminated against in history.
Retell the process of human understanding the shape of the earth. Ancient Indians thought that the earth was carried by four elephants and stood on a huge turtle. In ancient China, it was thought that the sky was like a pot, and it was semicircular. The ground is as flat as a square chessboard.
Zhang Heng, an astronomer in the Eastern Han Dynasty in China, believed that the sky is like an egg and the earth is like an egg yolk. There is water on the surface of the sky, like a yellow-wrapped eggshell.
Aristotle, an ancient Greek scholar, believed that the edge of the moon covered by the shadow of the earth was round, so the earth was a sphere or an approximate sphere.
What hypotheses have emerged in the slow process of human understanding of the shape of the earth? 1. The sky is round (the earth is square and the sky is round)
2. Geocentric theory (the earth is the center of the universe)
What is the process of human understanding the shape of the earth? Humans' understanding of the shape of the earth has generally gone through such a process: in ancient times, people only saw a small part of their living area because of their small range of activities, so they intuitively came up with various sayings of "the sky is round and the place is round". For example, in China, as early as the Zhou Dynasty more than two thousand years ago, there was a saying that "the sky is round and the place is like a chess board". The earth is like a square box. Russians think that the earth is like a shield, carried by three giant whales, drifting in the vast ocean. Indians have a similar legend, but they think that it is not a whale that carries the earth, but three elephants standing on the back of a turtle. When elephants move, they cause earthquakes? The shape and size of the earth affect the development of production technology, the expansion of human activities and the accumulation of various knowledge. People gradually realize that the earth cannot be flat in a large range, but should be curved. Because you see an offshore ship at the seaside, first the hull disappears, and then the mast sails. People who travel on land will lose some stars on the horizon in the south if they go north. Other stars appear on the northern horizon. If you go to the south, the situation is just the opposite. These phenomena can only be explained if the earth is curved. Aristotle, a famous scientist and philosopher in ancient Greece, demonstrated for the first time that the earth is spherical. He observed the celestial phenomena and inferred that the shape of the earth was spherical from the projection of the earth on the moon during the solar eclipse. At that time, some people who opposed it suggested: If the earth is really spherical, why should we live on the other side of the earth? Great geographical discoveries 15 and16th century, especially1519-1521year, the fleet led by Magellan successfully sailed around the earth once, which provided strong evidence that the earth was spherical. Matteo Ricci Tang Ruowang, a western missionary in the late Ming Dynasty, with the continuous progress of surveying technology, especially the use of artificial earth satellites, now the equatorial radius and polar radius of the earth are 6378 km and 6356 km respectively, with a difference of 2 1 km, and the equatorial circumference is 40000km. If we simplify this huge earth into a globe with a diameter of 1 m, the equatorial radius is only longer than the polar radius of1mm.
What is the process of human understanding of the shape of the earth? In ancient China, there was a saying that the sky was round like a cover and the place was like a chessboard, and there was also a saying that the sky was like a hat and the earth was like a cover. Sphere: Later, people speculated that the earth was a sphere according to the shapes of the sun and the moon, and Magellan's voyage around the world proved that the earth was a sphere. Ellipsoid: With the development of science and technology, people find that the earth is not a sphere through accurate measurement. It is a sphere with slightly flattened poles and slightly protruding equator. Irregular sphere: after further accurate measurement, it is found that the radius of different parts of the earth is not equal to the equatorial radius, and it is an irregular sphere. In the 20th century, satellite photographs of the earth confirmed that the earth was an irregular sphere. So the process of human understanding of the shape of the earth is: a round place-a sphere-an ellipsoid-an irregular sphere.
The process of human understanding the shape of the earth: Gaitian theory and Heliocentrism's geocentric theory
Geocentric theory is a cosmological theory that prevailed in ancient Europe for a long time. It was first put forward by the ancient Greek scholar Odysseus, and was gradually established and perfected by the further development of Aristotle and Ptolemy.
Ptolemy believed that the earth was at rest in the center of the universe. Seen from the earth, there are the moon, mercury, Venus, the sun, Mars, Jupiter and Saturn in turn, orbiting the earth in their respective circular orbits. Among them, the motion of the planet is more complicated than that of the sun and the moon: the planet moves on this wheel, which is executed along a uniform wheel. Beyond the sun and the moon, there is a celestial sphere inlaid with all the stars-the starry sky. Outside, it is the primitive earth that drives the movement of celestial bodies. The following is a schematic diagram of this theory:
Geocentric theory is the first planetary system model in the world. Although it is wrong to regard the earth as the center of the universe, its historical achievements should not be denied. Geocentric theory recognizes that the earth is "spherical" and distinguishes planets from stars, focusing on exploring and revealing the laws of planetary motion, which marks a great progress in human understanding of the universe. The most important achievement of geocentric theory is to calculate the execution of planets by mathematics. Ptolemy also put forward the concept of "execution orbit" for the first time and designed the current wheel balance model. According to this model, people can quantitatively calculate the motion of planets and guess the position of planets, which is an amazing creation. In a certain period of time, according to this model, the astronomical phenomena can be predicted correctly to a certain extent, so it also plays a certain role in production practice.
After all, Ptolemy pieced together the current wheel model in geocentric theory based on limited observation data, and he made this model consistent with the measured results by artificially specifying the current wheel and the size of the wheel and the execution speed of the planet. However, in the late Middle Ages, with the continuous improvement of observation instruments, the measurement of planetary position and motion became more and more accurate, and the deviation between the observed actual position of the planet and the calculated results of this model gradually appeared.
Those who believe in geocentric theory do not realize that this is caused by the error of geocentric theory itself, but use the method of adding this round to remedy geocentric theory. At first, this method can barely cope. Later, the number of small wheels increased to more than 80, but the exact position of the planet could not be calculated satisfactorily. This cannot but make people doubt the correctness of geocentric theory. /kloc-in the 6th century, Copernicus finally founded the "Heliocentrism" on the basis of the enthusiasm of ancient Greek ancestors and contemporary scholars for the sun. Since then, geocentric theory has been gradually eliminated.
Heliocentrism: The sun is the center of the universe, and the earth and other planets revolve around the sun. Heliocentrism is also called "Heliocentrism" or "Heliocentrism System". 16th century, after nearly 40 years of hard research, Copernicus, a Polish astronomer, systematically put forward Heliocentrism in his "On the Operation of Celestial Bodies" published in 1543 on the basis of analyzing a lot of previous data and his long-term observation. In Ptolemy's geocentric system, every planetary movement contains a one-year cycle, but Ptolemy can't give a reasonable explanation for this. Copernicus believed that the earth is not the center of the universe, but an ordinary planet, and the sun is the center of the universe. The one-year cycle of planetary motion is a reflection of the earth's annual revolution around the sun. Other contents of the Copernican system are:
(1) Mercury, Venus, Mars, Jupiter, Saturn and the Earth all revolve around the sun in uniform circular orbits.
The moon is a satellite of the earth. It orbits the earth once a month in a circular orbit centered on the earth, and at the same time revolves around the sun with the earth.
(3) The earth rotates once a day, but the sky doesn't actually rotate. It is precisely because of the rotation of the earth that the sun, moon and stars rise and set in the west every day.
(4) The distance between the star and the sun is far away, much larger than the distance between the sun and the earth. Copernicus listed the names of many ancient scholars who advocated the rotation of the earth and the revolution of the planets around the sun. He carried forward the thoughts of these scholars, spared no effort in his life, and established the Heliocentrism system with strict scientific argumentation through hard observation and mathematical calculation. Subsequent observations have continuously confirmed and developed this theory.
Limited to the level of scientific development at that time, Heliocentrism of Copernicus also had shortcomings and mistakes, that is:
(1) thinks that the sun is the center of the universe, but in fact the sun is only a central celestial body in the solar system, not the center of the universe;
(2) The old idea that planets move in a uniform circle is followed. In fact, the orbit of the planet is elliptical, and the speed of motion is not constant.
The story of Heliocentrism.
In ancient times, human ancestors stood in the wild desert and looked up at the sun, moon and stars in the sky, generating endless reverie.
Some people say that the sky is carried by a giant god standing on the ground. The theory of "covering the sky" is thus formed: the ground is flat, the sky is round, the middle rises, and the sides droop, just like a large hemispherical tent covering the ground.
Later, it was found in observation that Gai Tian Shuo could not explain the rise and fall of the sun, moon and stars, and only half a spherical shell was added under Gai Tian Shuo. Thus, "Huntington Theory" came into being.
In the 4th century BC, Aristotle founded "geocentric theory". Aristotle believes that the universe is a limited sphere, which is divided into two layers: heaven and earth. The earth is located in the center of the universe, so the sun and the moon revolve around the earth and objects always fall to the ground. There are nine equidistant celestial spheres outside the earth, and each celestial sphere will not move by itself. It is God who drives the celestial sphere of the star and drives all the celestial spheres. The earth where human beings live stands motionless in the center of the universe.
Ptolemy, as the last great astronomer in ancient Greece, completely inherited Aristotle's geocentric theory and expanded Aristotle's nine-level sky to 1 1.
Ptolemy imagined that all the planets move around a small circle, and the center of each circle moves on a circle centered on the earth. He called the circle around the earth "even wheel" and each small circle "current wheel". At the same time, he assumes that the earth is not completely in the center of the even wheel, but at a certain distance, and the even wheel is an eccentric circle. In addition to the above orbits, the sun, moon and planets also orbit the earth once a day with the stars, which makes the calculated results consistent with the measured results and has achieved practical value in navigation.
Ptolemy's geocentric theory caters to Christianity and is used by Christianity to maintain biblical theory. The Bible proclaims that the universe and the earth were created by God and the Lord, the earth is at rest in the center of the universe, the holy land Jerusalem is in the center of the earth, human beings are God's favorite children, and everything in the universe is created by God to meet human needs. ...
Thus, Ptolemy's "geocentric theory" became the Bible, and astronomy became the handmaiden of religion, which lasted until the Copernican era.
Copernicus was born in 1473 in a merchant family in Torun, Poland. When he was 10 years old, the plague took away his father. From then on, Copernicus began to live with his uncle Vukash. /kloc-When he was 0/8 years old, his uncle sent him to Krakow University, where Copernicus, with a keen mind, became very interested in astronomy and mathematics. He delved into mathematics, extensively dabbled in ancient astronomical books, devoted himself to the study of "geocentric theory", made many notes and calculations, began to observe astronomical phenomena with instruments, and began to conceive a new astronomical system in his mind.
Later, Copernicus came to study in Italy and studied at the University of Padua, where the academic atmosphere was very active. Nofara, a professor of astronomy at the university, expressed doubts about "geocentric theory" and thought that the structure of the universe could be expressed by a simpler schema. Under the influence of his thoughts, Copernicus germinated his views on the rotation of the earth and the revolution of the earth and planets around the sun.
After Copernicus returned to Poland, he continued his long-term astronomical observation and research, further confirming that the sun is the center of the universe. Because the forward and backward motion of the planet is an illusion caused by the different periods of the earth and other planets revolving around the sun. On the surface, it seems that the sun goes around the earth, but in fact, the earth goes around the sun with other planets. It's like sitting on a boat, obviously the boat is moving, but we feel the shore is retreating.
Copernicus observed and calculated day and night, and finally broke through many obstacles and founded the "Heliocentrism" with the sun as the center.
Copernicus once wrote a short talk about the main points of his "Heliocentrism" and copied it to some friends. His views immediately attracted the attention of European countries, but he dared not write them all for fear of persecution by the church.
However, Copernicus once said: "The bounden duty of human beings is to explore the truth." Under the strong impulse to explore the truth, he began to write the book Evolution with hesitation.
After many twists and turns, this six-volume scientific masterpiece "Theory of Evolution" finally came out with difficulty. At this time, Copernicus's life has come to an end. An hour before his death, he saw the book, which still smells like ink. He wiped the page with trembling hands and died suddenly.
The theory of celestial bodies clearly points out that all planets revolve around the sun as the center. The book says:
"The earth is moving."
"In addition to the rotation of the earth, there are still some movements that are still wandering. It is actually a planet. "
"among all these planets, the sun is proudly located in the town ... the sun is so high on the throne, ruling the planets around the children."
Although there are some shortcomings in the theory of natural evolution, it depicts the real picture of the structure of the solar system for the first time in human history, reveals the essence of the earth's rotation around the sun, reverses the relationship between the sun and the earth that has been reversed for more than 1000 years, causes a complete revolution in the world outlook in the Middle Ages, and deals a heavy blow to the theocracy of the feudal church.
geocentric theory
Geocentric theory holds that the earth is at the center of the universe, motionless, and the sun, moon, planets and other satellites all revolve around the earth.
The origin of geocentric theory is very early, which was originally put forward by the ancient Greek philosopher Aristotle. Around AD 140, the astronomer Ptolemy further developed his predecessors' theories and established the geocentric theory of the universe. The main points of Ptolemy's geocentric theory are as follows: First, the earth is at the center of the universe and stands still. Second, every planet rotates at a constant speed in a small circular orbit called the current wheel. However, the center of this circle revolves around the earth at a constant speed on a huge circular orbit called "even wheel", but the earth is not in the center of the even wheel, and it has a certain distance from the center. Third, the centers of Mercury and Venus are located on the line between the Earth and the Sun. The centers of Mercury and Venus turn once a year on even-numbered wheels, and the straight lines from Mars, Jupiter and Saturn to their respective centers are absolutely one week. Fourth, all the stars are located on a solid shell called "star sky". In addition to the above movements, the sun, moon and planets, together with the "starry sky", circle the earth once a day.
"Geocentric theory" was always dominant in 100016th century before the foundation of Heliocentrism.
The process of people knowing the shape of the earth; ()-() said you asked a professional question! I suggest you go to the library to find books on the history of geographical development!
What enlightenment have you got from the process of human understanding the shape of the earth? First, people's knowledge is limited, so we have to keep learning and making progress to find the real answer.
Second, we must have a big picture, and we must not lose sight of one thing and lose sight of another.
Third, the development path of everything is tortuous, and difficulties and setbacks on the road of truth are inevitable.
The long course of human understanding of the shape and size of the earth is recorded in the story of Pangu in ancient China, where a mother snail filled the sky. When talking about the creation of the world, ancient Greek mythology also refers to the birth of the universe from chaos, and the first god to appear is Gaia, the god of the earth. The sky, land and sea were born because of her. She is one of the most qualified and powerful gods, so people respectfully call her "Mother Earth".
Mankind has been exploring the essence of this land under our feet since it entered the civilized era.
As early as the 5th and 6th century BC, the Greek philosopher Pythagoras put forward the idea that the earth is spherical, and Aristotle inferred that the earth is round according to the circular shadow on the surface of the moon during the eclipse. This is the first time that mankind has explored the shape of the earth from a scientific point of view. /kloc-Copernicus, a Dutch astronomer in the 6th century, put forward the famous Heliocentrism after long-term observation and calculation, paving the way for human beings to know the earth. Later, Galileo, Kepler, Newton and other scientists continued to explore, especially after the 1960s, with the rapid development of science and technology and the launch of satellites, they found new means for geodesy. People already know that the earth is an extremely ordinary star in the vast universe-one of the nine planets in the solar system.