What is the shape of the earth? This is an interesting and important question.
In ancient times, because of the small range of activities, people only saw a small part of their living area.
Therefore, just by intuition, there are various sayings of "the sky is round and the place is round". For example, as early as two thousand years in China.
Many years ago, in the Zhou Dynasty, there was a saying that "the sky is round as a cover and the ground is like a chess board". Ancient Egypt
As we all know, the sky is like a dome-shaped ceiling and the earth is like a square box. Russians believe that the earth
Like a shield, carried by three giant whales, floating in the vast ocean. Indians have similar ones.
Legend has it, but they think that it is not the giant whale that carries this land, but the three heads standing on the back of the turtle.
Elephant. When an elephant moves, it will cause an earthquake.
With the development of production technology, the expansion of human activities and the accumulation of all kinds of knowledge, people gradually
It is recognized that the earth cannot be flat in a large range, but should be curved and arc-shaped. Because in the sea
Looking at the offshore ships, first the hull disappears, and then the mast sails. People who travel on land, if they go to the north,
Walking, some stars will disappear on the southern horizon, while others will be on the northern horizon.
Appear on the internet. If you go to the south, the situation is just the opposite. These phenomena can only be understood if the earth is curved.
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Around 500 BC, the ancient Greek mathematician Pythagoras and his disciples first put forward great ideas.
The hypothesis that the earth is spherical. They advocate using mathematics to explain the universe, thinking that in all three-dimensional graphics, the sphere
Is the most beautiful. The shape of the universe should be spherical, and all celestial bodies in the universe, including the earth, should be
It should be spherical. It took Aristotle, a famous scientist and philosopher in ancient Greece 100 years to visit the earth for the first time.
Prove that the earth is spherical. He observed the celestial phenomena from the projection of the earth on the moon during the eclipse.
It is inferred that the shape of the earth is spherical. At that time, some people opposed it: if the earth is really
It is spherical. Why don't people who live on the other side of the earth fall into the air below? At that time,
Because people don't understand gravity, it is difficult to answer this question.
Zhang Heng, an astronomer in the Eastern Han Dynasty in China, once said that "the sky is like a chicken, and the ground is like a chicken yellow".
Compare the universe to an egg, and the earth is like the yolk in an egg. This theory is called Huntian theory, which is better than the previous theory of covering the sky.
Great progress has been made.
15 and 16 century's great geographical discoveries, especially1519-1521a ship led by Magellan.
The team successfully sailed around the earth, which provided strong evidence that the earth was spherical. In the late Ming Dynasty,
Western missionaries Matteo Ricci and Tang Ruowang came to China and introduced scientific knowledge such as astronomy, geography and mathematics.
Knowledge, the translated name of "Earth" appeared in China.
So, is the earth a round right sphere? /kloc-at the end of 0/7, British physicist Newton root
According to the theory of gravity he discovered, due to the inertial centrifugal force produced by rotation, the earth's
Matter moves in the equatorial direction, so he came to the conclusion that the earth should have an equatorial radius greater than the polar radius.
Flat sphere. However, according to their meridian survey, the faction headed by Cassini, director of the Paris Observatory,
According to inaccurate data, when the earth revolves around the sun, it should extend to the poles, and it is a long ball, not a flat ball.
Ball. This argument lasted for half a century. Voltaire, a French enlightenment thinker, argued about the shape of the earth.
Once said: "In London, it is considered an orange, but in Paris, it is imagined as a watermelon." Until 18.
In 1930s, the French Academy of Sciences sent two expeditions, one to Lapland near the Arctic Circle and the other to Lapland.
Peru, near the equator in South America, measured the meridian length between the two places, but found that Cassini's measurement results were as follows
Wrong, and Newton's inference is correct.
With the continuous progress of measurement technology, especially the use of artificial earth satellites, earth measurement is now
The equatorial radius is 6378 140m and the polar radius is 6356755m. The difference between them is 2 1385m, and its flatness is
1/298.2。 In this respect, the earth is much more round than oranges.
In addition, people also found from the measurement that the equator of the earth is not a perfect circle, but is similar to an ellipse, which is the largest.
The radius differs from the minimum radius by more than 200 meters. It is also found that the northern hemisphere of the earth is thinner than the southern hemisphere; Arctic region
The geoid (mean sea level) in this area is about 10 meter higher than that in the reference oblate sphere and Antarctic area.
It should be recessed about 30 meters. So some people compare the shape of the earth to a pear and describe the globe as a pear.
Body.
In fact, the earth is neither like an orange nor a pear, but a sphere with its own unique shape.
If this huge earth is shrunk into a globe with a diameter of 1 m, the equatorial radius is only polar.
The radius is greater than 1mm, which is a subtle difference that cannot be expressed on the globe, so we use it.
The globe is still round.
Chen ershou
Why do we believe that the earth is round?
I don't mean thousands of astronomers and geographers, but ordinary citizens who read newspapers, such as you and me.
By John Orwell
In some places or other places-I think it is in the preface of Joan of Arc-Bernard Shaw thinks that we are more gullible and superstitious today than in the Middle Ages. As an example of modern credulity, he quoted a widely circulated example of believing that the earth is round. Ordinary people, Bernard Shaw, can't just give a reason to think that the earth is round. He just swallowed the theory, because something attracted the ideas of the 20th century.
Now, Bernard Shaw is exaggerating, but there is some truth in what he said. This problem is worth discussing to clarify modern knowledge. But why do we believe that the earth is round? I don't mean thousands of astronomers, geographers, etc. They can produce obvious evidence or theoretical basis, but ordinary citizens who read newspapers, such as you and me.
As for the plane earth theory, I believe I can refute it. If you stand by on the sea on a sunny day, you can see the masts and chimneys of the ships passing over the horizon, but the ships can't see them. This phenomenon can only be explained by assuming that the surface of the earth is curved. But it doesn't mean that the earth is spherical. Imagine another theory called the egg-shaped earth, which claims that the earth is shaped like an egg. What can I object to?
For those who hold the theory of spherical earth, the first card I played was to compare the appearance of the sun and the moon. The spherical man quickly replied that he didn't know. Through my own observation, those celestial bodies are spherical. All I know is that they are curved or flat. I didn't answer that man. Besides, he continued, why do I think the earth must be in the shape of the sun and the moon? I can't answer this question either.
The second card I played was the shadow of the earth: when there was an eclipse, the earth was projected on the moon, and it appeared as the shadow of a round object. But how do I know, ask the spherical earth theorist, is the eclipse caused by the shadow of the earth? The answer is I don't know. I just got this information blindly from newspaper articles and science books.
After failing in this unimportant communication, I now play my trump card: expert opinion. The royal astronomer, who should know, told me that the earth is round. The globe covered the queen card with his king card. I have tested the claims of the Royal Astronomers, and I even know a test method? So I played my trump card. Yes, I know a test. Astronomers can predict solar eclipses, which mentions that their solar system is quite sound. As for me, for my happiness, I can judge by accepting what they say about the formation of the earth.
If the spherical earth theorist answers-I believe what is true-the ancient Egyptians thought that the sun could also predict solar eclipses, so I lost my A card, and I only have one card left: sailing. People can sail around the world and reach their destinations, which is calculated on the assumption that the earth is a sphere. I believe I can completely defeat the spherical earth theorist in the argument, although he may have some chips.
It will be able to see why my view that the earth is round is the result of quite credulity. But this is the basic information outside the regulations. On most other issues, I will have to turn to an early expert, and it is unlikely to verify his statement. Most of our knowledge is at this level. It does not rely on reasoning or experiment, but on authority. Then, when the mountain of knowledge is so huge that once an expert leaves his professional field, he becomes an ignorant person himself. What's the difference? Most people, if they want to prove that the earth is round, will not even hinder the rather weak argument I mentioned above. They will say "everyone knows" that the earth is round first, and then they will get angry if they go forward. To some extent, Bernard Shaw is right. This is an age of credulity, and the knowledge load we have to bear now is part of the reason.