Why is the sun bigger at sunset than at sunrise

The sun at sunset appears larger than the sun at sunrise because of the diffraction effect of light rays during propagation. When sunlight encounters obstacles such as air molecules and dust in the atmosphere during propagation, it will deviate from the straight line, that is, diffraction. Due to the short wavelength of sunlight (white light), this deviation is not noticeable and difficult to detect.

However, when the Sun is near the horizon, the sunlight passes through a thicker atmosphere, and the diffraction is relatively more pronounced, and the Sun appears larger than at sunrise.

In addition, the sun at sunset appears higher than the sun at sunrise, also because of the refraction effect of the atmosphere. When sunlight passes through the atmosphere, the light rays are bent due to factors such as temperature, pressure, density, etc. of the earth's atmosphere. The deflection effect of the atmosphere on sunlight makes the sun appear higher than it actually is.

So, on the whole, the sun at sunset is larger than at sunrise, which is related to both the diffraction effect and the refraction effect of the atmosphere.

Because the sun in the morning obliquely touches the ground, and the sun hits the earth at noon, the direct radiation is higher than the oblique heat. At the same time, at night, the heat of the sun shining on the ground has long since been lost. So it feels cool in the morning, and at noon when the sun hits the ground, it feels hot.

The temperature is hot or cold, which does not indicate how far or near the sun is from the ground, but how long the sun shines on the ground.

The sky was still a light blue, very shallow, very shallow. In the blink of an eye. A red glow appeared where the sky and water met. The range of the red glow slowly expands, getting brighter and brighter. I knew that the sun was about to rise over the horizon, so I couldn't take my eyes off it.

Sure enough, after a while, the little half of the sun's face appeared, very red, but there was no light. The sun seemed to be carrying some kind of burden, slowly, vertically and vertically, and rose vigorously. In the end, it finally broke through the clouds and jumped out of the sea completely, and the color was so lovely red.

In an instant, the crimson round thing shone brightly, making people's eyes hurt. The clouds next to it suddenly shone brightly.

Sometimes the sun hides in the clouds. The sunlight shines directly through the cracks in the clouds to the surface of the water, and it is difficult to distinguish **is water, **is the sky, and only a brilliant light is seen.

At sunrise, the angle between the sun and the ground is 0° 180°.

At noon, the angle between the sun and the ground is theoretically 90°, but this is called the noon solar altitude angle, and the noon solar altitude angle is determined by the latitude position of the place and the position of the direct point of the sun.

At sunset, the angle between the sun and the ground is 0° 180°.

Introduction to the direct sun point:

The direct solar point is the point where the angle of incidence of sunlight on the earth's surface (i.e., the angle of solar altitude) is 90 degrees, and it is the intersection of the geocentric and heliocentric lines and the earth's spherical surface. It is 12 noon at the meridian where the direct point of the sun is located.

The pattern of activity is as follows: at the vernal equinox (around March 21), the direct point of the sun is at the equator (0°), and then moves northward. On the summer solstice (around June 22), the direct point of the sun is on the Tropic of Cancer (23°26 N) and then moves south.

At the autumnal equinox (around September 23), the direct point of the sun is on the equator (0°) and continues to move south. On the winter solstice (around December 22), the direct point of the sun is on the Tropic of Capricorn (23°26 s), after which it moves northward.

This natural phenomenon is caused by the rotation of the earth.

The rotation of the earth] The rotation of the earth can be related to the day and night that you can see. Because the earth is an opaque sphere, at any given moment, the sun's rays can only illuminate half of the earth, and the hemisphere illuminated by the sun is daylight; The hemisphere that is not illuminated by the sun is night. Coupled with the fact that the rotation of the Earth ensures that a certain hemisphere is not always in day or night, a day-night alternation is formed.

This is the rotation of the earth (you can refer to the People's Education Publishing House, Grade 7 Geography, Volume I [Figure.])

People's Education Edition Geography 7th Grade Volume 1 Map.

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

1. Refer to the illusion caused by burying slow objects. 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 evening sun, only one corner of the horizon is the sky, and the rest of the sun is backed by trees, houses, etc., while at noon, the sun is overhead with an incomparably large sky as its backing, so it seems that the noon sun 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 first rises, the sky is dark and dreary, so that the sun appears bright before the bend, 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 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 density of the atmosphere is relatively low and the density of the atmosphere is relatively high, the density of the atmosphere is smaller, so that the sun looks larger in the morning and evening, and it looks smaller at noon.