The question of how far the sun is, why is the sun so big and so small

Regarding the distance of the sun from people, it is necessary to combine the revolution and rotation of the earth, and also to see the latitude and time of people on the earth.

The earth revolves around the sun, and the orbit is an ellipse, and the sun is at a focal point of this ellipse, so the distance of the earth from the sun is related to the position of the earth in the orbit of the earth. On the summer solstice, the Earth is at aphelion.

The Earth is farthest from the Sun; During the winter solstice, the Earth is at perihelion.

The Earth is closest to the Sun. From perihelion to aphelion, i.e., from the winter solstice to the summer solstice, the Earth revolves.

, constantly moving away from the sun; During the summer solstice and winter solstice, the Earth is getting closer and closer to the Sun. It can be seen that the sun is the closest at the winter solstice. This is from a year, if you look at it from one day, how does the distance of the earth from the sun change?

If the Earth moves no other than its rotation, and its axis of rotation is perpendicular to the straight line between the Sun and the Earth, then at the same time people at the equator are closest to the Sun and people at the poles are farthest. However, the Earth rotates at an angle, so the difference between morning and evening is greater at the equator, and the greater the latitude (i.e., the farther away from the equator), the smaller the difference between the distance between the Sun at noon and between morning and evening.

If the Earth is completely stationary, the area in the middle hour is closer to the Sun than the area in the morning hour. But the earth is not completely stationary, but is in constant rotation and revolution, so the distance between the sun and the person who is observing it is the shape of the earth and the latitude of the earth.

Sunrise time and the rotation of the Earth.

The slow change in the direction of the axis is related to the slight effect of the gravitational pull of the planets on the Earth's orbit, but the change in distance is negligible compared to the straight-line distance between the Sun and the Earth.

It can be seen that on the same day, at different times, in different places, the sun is far and near from people. It's just that this distance is so small compared to the distance of the sun from the earth that it doesn't need to be considered at all, like a heavy elephant.

The weight of a few hairs on the body is negligible. So, in a day, in the same place, the sun should be the same distance from the earth in the morning and at noon.

In the temperate regions of the northern and southern hemispheres of the earth, there are four seasons of spring, summer, autumn and winter throughout the year, which is caused by the direct sunlight shining at different latitudes on the earth.

Near big and far small"It is the objective law by which people observe objects, and it is precisely because of this law that the relative position relationship between various objects can be reflected in the field of vision.

People see that the sun at sunrise and sunset is "bigger" than the sun at noon, not because it is "near and far small". From sunrise to sunset, the distance between people and the sun basically does not change, and the reason for this visual effect is that the "reference" of people when observing the sun is different.

At sunrise, the sun appears to be "bigger" because the sun is in the same field of view as nearby objects on the horizon, and the reference object is an object on the ground. At noon, because the sun is in the vast sky, the reference object is the vast and infinite space, and the sun seems to be relatively "small".

It is indeed large and near, but the sun is oblique in the morning, and the sun is direct at noon, and the sunlight will be lost through the atmosphere, so the energy brought by direct radiation is more, so it is hot at noon.

When the Earth is at perihelion, it is winter in the Northern Hemisphere and summer in the Southern Hemisphere, because the Sun is directly shining in the Southern Hemisphere, and the Earth is in the Northern Hemisphere at aphelion, and it is winter in the Southern Hemisphere, because the Sun is directly shining in the Northern Hemisphere.

In fact, the change of the seasons is mainly due to the problem of the angle of direct sunlight, the closer the angle is to 90°, the hotter it is, and vice versa.

The reason why the angle of direct radiation always changes is that the earth's rotation plane and rotation axis have a certain angle.