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# The diameter of the sun is 400 times that of the moon, but they look the same size

Some people say that the sun, the moon, and the earth are a pair of mysterious combinations! Because the diameter of the sun is about 400 times the diameter of the moon, and the distance from the sun to the earth is exactly 400 times the distance from the earth to the moon, the moon in the sky is as big as the sun when viewed from the ground. The diameter of the sun is 1.392 million kilometers, and the diameter of the moon is 3446 kilometers. The average distance between the sun and the earth is 150 million kilometers, and the average distance between the earth and the moon is 380,000 kilometers. From the data point of view, this is indeed very coincidental.

Astronomers explain that this is an astronomical coincidence! It is precisely because of the existence of this wonderful coincidence that we can see the wonderful scene of the total solar eclipse on the earth. During a total solar eclipse, the moon completely blocks the sun's light, and the entire earth becomes dark. In the solar system, no special combination like the sun, moon, and earth has been found so far. Moreover, the mass of the moon accounts for 1.23% of the mass of the earth. It is quite unique in the solar system that such a small rocky planet as the earth can have a satellite as large as the moon.

Regarding this miraculous phenomenon, some people think that this is not a coincidence, because this kind of coincidence seems so incredible to them, it is hard not to make people suspect that it was designed. This designer, people think it is a god, and some people think it is an alien. However, the various opinions are all speculations, not only without substantive evidence but also with poor logic. Many people have refuted this conspiracy theory, but many people still believe it. This is actually understandable, after all, everyone's cognitive level is different. Everyone was told that the earth is a sphere when they were in elementary school, and they gave you many examples, but do you know? There are still some people in the world who think the earth is flat.

In fact, it is really a coincidence that the moon in the sky looks as big as the sun, and it is a coincidence that only exists in this time period. This coincidence is an episode in hundreds of millions of years! According to scientists' research, the moon was formed as a part of a large celestial body at the beginning of the solar system that collided with the original earth. When the moon was just born, it was very close to the earth at that time, only tens of thousands of kilometers, and the rotation speed of the earth was also very fast at that time. As the moon is gradually moving away, the moon is now 380,000 kilometers away from the earth, and the earth's rotation speed is much slower than when it was born. The rotation period is currently about 24 hours.

In the 4.5 billion years of life on the earth, the orbit of the earth has hardly changed much. Based on this, we can know that, more than a billion years ago, the moon in the earth's sky looked bigger than the sun. And in that period, there was no such coincidence between the sun, the moon, and the earth at all. In fact, the source power that makes all this happen is inertia and gravity, and the ruler that produces this wonderful combination is the law of physics. All kinds of celestial bodies in the universe are constantly moving, and their relative positions and motion states will change with time, and they are not eternal. For example, the Polaris we know well is not a constant star in the sky, it will also change with time. After tens of thousands of years, the shape of the Big Dipper will also change significantly due to the movement of distant stars, and finally, the shape of the Big Dipper will become fragmented.

To answer another netizen's question, why are the earth, moon, and sun suspended in space and not falling down? The reason why objects on the earth fall down is because of the existence of gravity, but there is no gravity in space, and of course, there is no such direction as up and down. Since there is no such thing as up and down, of course, there will be no falling down. Suspension force is the reaction force generated by gravity. Space is a vacuum without gravity, so they are not suspended in space. There is no force in space to support their existence, and they do not need such support or suspension force. As for why they run very regularly, it is because of the existence of universal gravitation.