There is a "blue sun" over Beijing again. What caused it?

The color of the sun depends only on itself. During the sandstorm, dust particles get bigger and occur? Michaelis scattering? Activities. At this time, the particle size of dust is usually larger than the wavelength of visible light, and the red and orange light with the wavelength closest to the particle size will be significantly scattered, thus reducing the red light seen by the naked eye, so the sun looks slightly blue. In fact, as long as there is similar air suspension, it will cause the blue sun phenomenon. So there is no need to panic in this situation.

Usually, the sun in the sky is white. Why does it become in dusty weather? Blue sun? ? What is the principle? Hu Xiao, chief meteorological analyst of China Meteorological Network, gave a simple answer. Although this is because the particles in the sand tend to absorb longer red light, he did not introduce the principle in detail. So my class tried to explain it. What we think of as white sunlight is actually not white. It consists of seven colors: red, orange, yellow, green, blue, indigo and purple. The seven colors of the sun are separated, with beautiful colorful light, just like a rainbow.

Why do ordinary prisms separate seven kinds of sunlight? The main reason is that the wavelength of each color light is different. The wavelength of red light is the longest, reaching 740 nanometers. The wavelength of violet light is the shortest, only 380 nanometers. Different wavelengths have different refractive indices. This is why a prism can divide sunlight into seven colors. Like electromagnetic waves, the longer the wavelength, the stronger the penetration of light, so the penetration of red light is higher than other light intensities. I don't know if you have ever played with a laser pointer. You can shoot a bright red spot far away, and hundreds of meters is not a problem. In addition to the low production cost, there is another reason that the light emitted by the red light is far away.

But everything has its vanquisher. When a large number of coarse particles are suspended in the atmosphere, some particles even exceed 75 microns. They only absorb the red light in sunlight and let other light pass through. The red light doesn't work. Blue light will be significantly enhanced and will appear? Blue sun? . It can also be seen from the photos that the weather in Beijing is really bad, the visibility is not very high, and the houses in the distance are not very clear. Is there one in the sky? Blue sun? . Don't contact too much. It is not a harbinger of a phenomenon, nor is it that we have really been to Mars. This is an irresistible natural phenomenon, which is only related to dusty weather. Of course, we can change in the future. What should I do in such bad weather? I believe Beijingers must be experienced. Wear masks when going out and close doors and windows to avoid unnecessary respiratory diseases. Everyone has only one life.