Why does the sunset look bigger than when it is high in the sky?

As you know, the shape of the Earth's orbit is an ellipse that is close to a perfect circle, and the distance between the Sun and the Earth changes constantly as the Earth revolves around the Sun. The closest point in the Earth's orbit to the Sun, that is, the end of the long axis of the elliptical orbit closer to the Sun, is called perihelion. In modern times, the date of the Earth's perihelion is around the beginning of January every year.

At this time, the Earth is about 147.1 million kilometers from the Sun, commonly known as perihelion. The farthest point in the Earth's orbit from the Sun is called aphelion. The date of the aphelion of the Earth is approximately at the beginning of July each year.

At this time, the Earth is about 152.1 million kilometers from the Sun, which is commonly known as aphelion. The average of the perihelion and aphelion is 149.6 million kilometers, which is the average distance between the Sun and the Earth, or 1 astronomical unit. From the above, we will know that although the sun is far away from the earth in time, it is by no means a single day, so this assertion is wrong.

As for why the sun looks smaller at noon and the rising sun and sunset are larger, let's first discuss two questions:1How vision is formed.

The light emitted by the object is imaged on the retina by the lens (lens) of the human eye, which sensitizes the photoreceptor cells, and then transmits the information to the cerebral cortex by the optic nerve, and forms vision after information processing and processing. To a certain extent, the original has been modified. For example, an object of the same size, a black one appears smaller than a white one, a blue sky in a painting appears farther away than a building, and so on.

In short, the contrast between the target and the background, the difference in color, the contrast of the color, etc., will be modified to varying degrees. 2.The role of the Earth's atmosphere.

Whether the sun rises over the eastern horizon or before it descends into the mountains to the west, the light waves it emits travel more than twice as far through the Earth's atmosphere as it would if it were shining directly overhead. At this time, after the sunlight is absorbed and scattered by gas molecules, small dust, ice crystals, and water droplets suspended in the earth's atmosphere, most of the blue light and violet light with shorter wavelengths in the light wave are absorbed or scattered, leaving only the red light and orange light with longer wavelengths to reach the surface and be observed, so the rising sun and sunset look not golden, but red.

We understand these two questions, and the results come out: because the background of the morning sun and the setting sun is darker, the bright target on the dark back appears larger, and the morning sun and the setting sun are red, and people use the ground objects as references, so the morning sun looks big and round. But the evening sun appears flattened, which is caused by the refraction of light.

At noon, the sun is high in the sky, and with the sky as the background, there is no other reference, so it looks smaller.

When hanging high in the sky, the reference is the vast sky.

The morning sun and the sunset reference are buildings and trees.

It will be one big and one small in comparison.

This is due to the refraction caused by the fog, which is a kind of "parhelion" phenomenon, because in the fog there are many columnar ice crystals floating in the air, from an optical point of view, it is like a multi-prism, when the sun is shining on this ice crystal, it will occur very regular refraction, so we can see "two sunsets".

The main reasons why you feel like the sun is big at sunrise and sunset are:

1. The illusion of jujube made by reference. Under certain conditions, people will have the illusion of seeing objects, an object will appear larger in the middle of some small objects, and an object will appear smaller in the middle of some large objects. In the same way, in the morning and dusk, only one corner of the horizon is the sky, and the rest of the sun is backed by trees, stools, houses, etc., and at noon, the sun is overhead, and the sky is extremely large overhead, so it seems that the sun at noon is smaller than the morning sun.

2. The effect of "light osmosis". The white figure is larger than looking at a black figure of the same size. In physics, it is called "photoosmosis".

When the sun rises, the surrounding sky is dark and dreary, so the sun appears bright, and at noon, the surrounding sky is very bright, and the difference in brightness between the sun and the backing is not so great, which is why the sun is larger in the morning and evening than at noon.

3. The refraction of light produced by the atmosphere. Due to the existence of the atmosphere, and the lower terrain has a higher density of the atmosphere, and the density of the atmosphere is lower than that of the higher terrain, the sun looks larger in the morning and evening, and smaller at noon.

Regarding this issue, the "Two Children's Debate" first appeared in "Liezi".

The story tells that when Confucius was traveling to the East to study, he saw two children arguing, and Confucius asked them the reason for the argument. One child said, "I think the sun is close to people when it comes out, but far away at noon."

Another child thinks that the sun is far away when it first comes out and close at noon. A child said, "When the sun first comes out it looks like a big round canopy, and at noon it looks like a plate or a bowl.

Another child said, "The sun has just come out and it is cool and cold, and when it comes to noon, it is so hot that it is like reaching into hot water." Isn't this just the feeling of being hot when you are close and the feeling of being cold when you are far away?

Confucius could not determine who was right and who was wrong. The two children laughed and said, "Who says you know a lot of things?"

This story was made up, and it was used by Liezi to ridicule Confucius's ignorance. In fact, the questions raised by the two children are also the questions raised by Liezi. This question cannot be solved by Liezi. Because this was a problem that people at that time simply could not solve.

Now we know that the average distance between the Earth and the Sun is 149.6 million kilometers. Although there is a difference between the distance between the sun and the earth in the morning and noon, the difference is so small as the distance between the earth and the sun that it does not produce changes in the size of the sun or the heat or cold that we perceive.

So why is the morning sun big and round, while the midday sun looks much smaller?

It turns out that under certain conditions, people can have an illusion of vision of objects. An object appears larger in the middle of some small objects, and an object appears smaller in the middle of some larger objects. It's the same with looking at the sun.

Because in the morning, the sun is rising, and people use the ground objects as references, so the morning sun looks big and round. This is also true for the evening sun to appear larger, but the evening sun appears flatter due to the refraction of light. At noon, the sun is high in the sky, with the sky as the background, and there is no other reference, so it looks smaller.

Also, we look at a white figure that is larger than a black figure of the same size. This is called "photoosmosis" in physics. When the sun rises, the surrounding sky is dark and gloomy, so the sun appears bright.

At noon, the sky is bright all around, and the difference between the brightness of the sun and the backing is not so great, which is why it looks like the sun is bigger in the morning than at noon.

As for the change of heat and cold, it is not caused by distance or proximity. Noon is hotter than morning because the sun shines directly on the ground at noon, while the morning sun shines obliquely on the ground. When the sunlight is direct, the ground and air receive more radiant heat from the sun at the same time and in the same area than when the sunlight is oblique in the morning, so the heat is the strongest.

So it is hotter at noon than in the morning and late afternoon. Of course, by noon the sun is exposed for a long time, and the ground absorbs a lot of solar radiant heat, which is also what makes the temperature rise. And in the morning, when the sun has just risen, it is naturally not too hot.

caused by human visual illusions. The sun itself has not "gotten bigger".

At dusk, when the sun is closer to the horizon, the buildings and landscapes on the ground that are much smaller and darker than the sun become the reference of the sun, and the vast sky becomes the reference of the sun during the day, in contrast, we will feel that the sun at dusk is larger than during the day.

There is a similar example, the white dots on black paper look larger than the black dots on white paper, which is also due to the illusion caused by the different references to the naked eye, as well as the visual expansion of bright colors, which is also the reason why fat people like to wear black dark clothes.

At noon, the sunlight is perpendicular to the ground, and the light is basically not refracted when it passes through the atmosphere, and the angle between the sunlight and the ground gradually decreases after noon, and the refraction phenomenon becomes more and more obvious when the sunlight passes through the atmosphere. So the sunset gets bigger.

The sun is the same distance from the earth in the morning and at noon. Why does the sun look bigger in the morning than at noon? It's a visual error, an illusion.

The same object, placed in a group of objects larger than it, appears small, while placed in a group of objects smaller than it appears large. In the same way, the morning sun rises from the horizon against the backdrop of trees, houses, distant mountains and a small corner of the sky, and in this comparison, the sun appears larger. At noon, when the sun rises high and the vast sky is the backdrop, the sun appears smaller.

Secondly, the white part of the same object appears larger than the black one, and this physical phenomenon is called "photoosmosis". When the sun is rising, the background is a dark and dreary sky, and the sun is exceptionally bright; At noon, the background is a blue sky, and the sun does not contrast much with its brightness, so it appears smaller.

The temperature is higher at noon than in the morning, is the sun closer to us at this time than in the morning? Neither is it. The main reason is that the sun hits the earth obliquely in the morning and the sun shines directly on the earth at noon.

At the same time and in the same area, direct radiation is higher than oblique heat. At the same time, at night, the heat of the sun shining on the ground dissipates, so it feels cool in the morning; At noon, the heat of the sun hits the ground, so it feels hot. The temperature is hot or cold, and it does not indicate how far or near the sun is from the ground.

Because the refraction of light gives people the illusion that the sun is actually the same size.

ps.The sun we see at sunrise and sunset is just an image of the sun, not a real sun.