When is the sun closest to us? Two children debate the day! Brief description of the applicant !!!!!

The Earth's orbit around the Sun is a nearly circular ellipse, and the Sun is located at a focal point of the elliptical orbit, so that the distance between the Sun and the Earth is constantly changing over the course of a year or even a day.

At the beginning of January every year, the Earth is at the perihelion of its orbit around the Sun, and the distance between the Sun and the Earth reaches a minimum value, which is about 100 million kilometers.

At the beginning of July every year, the Earth is located at the aphelion point of its orbit around the Sun, and the distance between the Sun and the Earth reaches its maximum value, which is about 100 million kilometers.

Compared with the average distance between the Sun and the Earth (100 million km), the difference in the distance between the Sun and the Earth in one year (100 million km) is almost negligible. Then in a single day, the change in the distance between the sun and the earth is even more insignificant.

If you had to compare the distance between the sun and the earth in the morning and at noon, one would think that the sun at noon would be closer, because the morning sun shines from the horizon and is a distance of the radius of the earth than the sun at noon.

Whether this statement is correct or not, let's analyze it.

From the above data, it can be seen that from January to July, in half a year, the change range of the distance between the sun and the earth reached 5 million kilometers (100 million kilometers minus 100 million kilometers), the change value in each day was 10,000 kilometers, from morning to noon about 6 hours, for a quarter of a day, and the change value of the distance between the sun and the earth was about 6868 kilometers, which was greater than the radius of the earth.

If the Earth is moving towards perihelion, from morning to noon, on the one hand, it is indeed closer to the distance of the Earth's radius (more than 6,300 kilometers), and on the other hand, after a quarter of a day, the distance between the Sun and the Earth is also 6,868 kilometers.

But if the earth is moving towards aphelion, from morning to noon, on the one hand, from the earth to the sun is also close to the distance of about a radius of the earth (more than 6,300 kilometers), but on the other hand, after a quarter of a day, the distance between the sun and the earth is 6,868 kilometers, and the two are superimposed, and the noon is even farther from the sun.

Therefore, whether it is closer to the sun at noon or closer to the sun in the morning depends on what time of year it is.

The second pair. Ignoring the revolution of the earth and considering only the rotation, from the center of the sun to a fixed point on the earth's surface, the distance must be long in the morning and short at noon. It's just that this change in distance is not enough to cause hot at noon and cool in the morning, and the hot at noon and cool in the morning is caused by the angle of incidence of the sun, not the truth mentioned in "Two Children's Debate".

Uh, there's one more answer

The farthest place to reach the sun is in July every year.

The Earth's orbit around the Sun is elliptical rather than a standard circle. Every year on the first day of July, we reach the farthest point in orbit from the Sun. So why was it so hot at that time?

In fact, there is not much difference between the impact of the Earth being "close to the Sun" and "being far from the Sun" on the Earth's climate.

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.

At 2 p.m. The diurnal range is minimal, and the Sun is closest to the Earth 1. The distance of the Sun from the Earth is the same in the morning and at noon. 2. It is close at noon, and we are far away from the sun in the morning

Because there are clouds on the surface of the earth in the morning, if you look at the sun through the clouds, the sun is bigger. When the clouds dissipate at noon, the sun appears small, but the size of the sun has not changed. It is not correct to describe the distance of the ground from the sun according to different senses.

A child said that the sun is cool in the morning and hot at noon, and it is also incorrect to explain the distance of the sun from the ground from the body's perception of temperature. Because the heat of the sun shining on the ground dissipates at night, it feels cool in the morning; At noon, the heat of the sun hits the ground, so it feels hot. The heat and coolness of this temperature does not indicate how close the sun is to the ground.

Later, scientists finally calculated that the average distance between the Earth and the Sun was 149.6 million kilometers.

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 dark, so that the sun appears bright, and at noon, the sky is bright, and the difference between the brightness of the sun and the backing is not so great, which is why it seems that the sun is bigger in the morning than at noon.

In short, the sun is at the same distance from us in the morning and at noon, so its size is the same, and it seems that the sun is bigger in the morning than at noon because of the illusion of the eye.

Also, is it because the sun is closer to us at noon than in the morning? Neither is it. So why?

Noon is hotter than morning because the sunlight is directly on the ground at noon, and the morning sunlight is obliquely on the ground. So noon is hotter than morning.

In fact, the heat and coldness of the weather are mainly determined by the temperature of the air. The main factor affecting the air temperature is determined by the intensity of the sun's radiation, but the solar heat is not the main reason for the direct increase in air temperature. Because the heat energy directly absorbed by the air into the sunlight is only a small fraction of the total heat energy of solar radiation, most of which is absorbed by the ground.

The ground absorbs the heat of solar radiation, and then conducts it upwards to the air through heat transfer methods such as radiation and convection, which is the main reason for the increase in temperature.

In short, the fact that the sun is hot at noon and colder in the morning is not because the sun is far or near our earth.

At noon on the day of the winter solstice, the sun is closest at this time of the year.

The second one is right, when you look at a basketball with your eyes, what you see is a circle, do you say that the center of the circle is close to your eyes or the edge of the circle is close to your eyes?

And the eyes represent the sun, the basketball is the earth, the earth is autobiographical, our position is also rebecome, the center of the circle is our position at noon, the circle edge is our position in the morning, which one do you say is close?

You should get the idea, right?

The sun is the same at any time of the day.

In fact, the sun is always as close at all times.

According to the ancient Chinese "Liezi Tang Wen Chapter", in the Spring and Autumn Period more than 2,000 years ago, some people debated the question of when the sun was closest to us. One says: The closer an object is to us, the bigger it looks; The farther away from us, the smaller it looks.

The sun that rises in the morning looks bigger than the sun at noon, so the morning sun is close to us. The other said: The closer we are to the furnace, the hotter it gets; The farther away you are, the less hot it feels.

The midday sun is hotter than the morning sun, so the midday sun is closer to us. Both of these statements seem to be reasonable, and no one can convince anyone. But when exactly is the Sun closest to Earth?

As we all know, in addition to its rotation, the earth also revolves around the sun, and the orbit is an ellipse. The Sun is located at one focal point of the ellipse. If we take the sun as the coordinate origin and the major axis of the ellipse as the polar axis, then the equation of motion of the earth can be written as:

where e is the eccentricity of the ellipse, therefore, when cos?=1, r is the minimum, when the earth is closest to the sun, and the corresponding time is January 2 of each year. When cos?

-1, r is the maximum, when the Earth is farthest from the Sun, corresponding to July 5 of each year. Thus, for the time of the year, the Earth is at perihelion on January 2 and aphelion on July 5. During the period when the Earth moves from perihelion to aphelion, the Sun is farther than sunrise at noon, 1,000 kilometers in early February and 6,400 kilometers in early April.

When the Earth moves to aphelion, this difference disappears. Conversely, as the Earth moves from aphelion to perihelion, the Sun is closer at noon than at sunrise, nearly 5,800 km in mid-July and 16,000 km in mid-September, when the difference disappears again at perihelion. And so on year after year, never stopping.

Therefore, we can neither judge when the sun is closer to us by its visual size during the day, nor can we judge its distance by how hot or cold it is.

At noon on the summer solstice, think for yourself.