When is the sun closest to us and farthest from us?

The distance between the sun and the earth is the same in the morning and at noon. The reason is that the sun is about 6,400 kilometers away from us (that is, radius of the earth), but this difference is negligible compared with the distance from the earth to the sun (the distance from the earth to the sun is about150,000,000 kilometers), so the sun in the morning and at noon can basically be said to be the same distance. Why does the sun look bigger in the morning than at noon? This is a visual error and illusion. The same object appears small in a group of larger objects, but large in a group of smaller objects. Similarly, the morning sun rises from the horizon with trees, houses, distant mountains and a small corner of the sky as the background. In this contrast, the sun looks bigger at this time. At noon, the sun rises high and the vast sky is the background. At this time, the sun appears small. Secondly, the white object of the same object is bigger than the black object. This physical phenomenon is called "light penetration". When the sun rises, the background is a dark sky and the sun is particularly bright; At noon, the background is the blue sky in Wan Li, and there is little contrast between the sun and its brightness, so it is smaller. It's nearly noon, and we are far away from the morning sun. The reason is that at the same position from the sun, at noon, there is an angle difference between the time when the earth rotates facing the sun and the time when it looks at the sun in the morning. Geometric calculation, assuming that the sun is stationary, is a point, and the observation of the earth in the morning and at noon differs by an arc on a sphere. I haven't worked out the details, but I can think about it. 3. Discuss according to the situation. If it is at the poles, it will be close to noon in the morning or evening. If you are on the equator, the diameter of the earth is less at noon than at midnight. I think the above three explanations seem reasonable, but they are not considered comprehensively. The time for the earth to move from perihelion to apohelion is a case, and the time for the earth to move from apohelion to perihelion is an hour. These two situations are mainly caused by the revolution of the earth. The sun looks big and round in the morning and evening, but it looks smaller at noon. So, in a day, is the noon sun near us, or the morning and evening sun near us? As we all know, the earth's orbit around the sun is elliptical. Apogee is 6.5438+0.52 million kilometers from the sun, and perigee is 6.5438+0.47 million kilometers, with a difference of 5 million kilometers. It takes 365 days, or 8760 hours, for the earth to orbit the sun once, and its radial movement distance is 654.38+0 million kilometers. The average speed of radial motion is1141.5 km/h, and the time from morning to noon is counted as 6 hours, so the displacement between the earth and the sun is 6849km due to the radial motion speed of the earth, which is obviously larger than the radius of the earth. From the above analysis, we can see that when the sun is closer to us in a day is determined by the position of the earth in the sun's orbit. When the earth reaches perihelion (about 65438+February 22, winter solstice), the sun is closest to the earth. From this day on, the earth began to move away from the sun and reached the farthest point until the apohelion (around June 22, summer solstice). Therefore, during the earth's movement from perihelion to apohelion, the morning sun is always closer to us than the noon sun. In the process of moving from apohelion to perihelion, the morning sun is always farther than the noon sun.