What color is the sun?

Take the seven colors of the rainbow as an example. The "light" of the sun consists of seven colors: red, orange, yellow, green, blue, indigo and purple. Light is an electromagnetic wave, and its color will be different with different wavelengths. Among them, the wavelength of red light is the longest and that of violet light is the shortest, so the wavelengths of seven colors are red, orange, yellow, green, blue, indigo and purple in turn. Due to the short wavelength of violet light, the refraction amplitude is larger than that of red light with long wavelength. This is why purple light is located inside the rainbow and red light is located outside the rainbow.

Let's go back to the sun itself. You must think how can it be green? After all, when watching the sunset, the sun is obviously white, orange and red, but it won't be green anyway! In fact, this is because at night, when the sun shines obliquely, the distance through the atmosphere becomes longer and the number of encounters with obstacles (air, etc.) is more. ) increase. ) becomes more frequent. However, the light of other colors with shorter wavelength scatters at high altitude and can hardly reach the ground, leaving only red light and orange light with longer wavelength to reach the ground, so the sun will appear orange-red.

Taking the sun as a star, its radiation peak is just at the junction of blue and green in the spectrum, so from the perspective of light, the sun is a green star! Or better yet, blue-green stars. The temperature of a star will also be directly reflected in the color it displays. For the sun, its surface temperature is about 6000 degrees. As mentioned above, we always think that the sun is actually yellow and white because of the error of human eye color discrimination.

As mentioned above, the longer the wavelength of light, the more it can pass through obstacles in the atmosphere (such as oxygen, nitrogen molecules, dust, water vapor); Blue, indigo and violet light are easy to scatter when encountering obstacles in the atmosphere because of their short wavelengths, so when we look at sunlight, blue-green is blurred, which is why we think it is white. I know you may say, isn't the sky blue, too That's because the human eye is very sensitive to blue, so we usually see the blue sky.

Do we have a chance to see the green sun? If we sum up the above statement, the first or last thing we see at sunrise or sunset should be blue light. But blue light is easy to scatter in the air, so it is difficult to see. Usually, we see green light with a slightly longer wavelength than blue light. So, if you have a chance to watch the sunrise at the seaside when the weather is clear, you can see the green sun when only a small part of the sun is above the horizon and the air quality is fresh! But only for a few seconds!

This should be the coolest little knowledge you have seen today! No matter how complicated it is. In short, the color of light will change because of temperature and wavelength, and the wavelength of light that human eyes can see is limited, which is why the sun we usually see is not green!