Stay indoors at sunrise and travel thousands of miles at sunset. What does this proverb mean?

Literally, this proverb means that when people get up in the morning, if they see a red cloud on the horizon, it indicates that it may rain today and it is not suitable to go out. If they see burning clouds at night, tomorrow will be a better weather and suitable for going out.

The appearance of Xia Hong means that the clouds and rain in the west will move, so "the morning glow never dies" and you see the sunset glow at night, which means that the clouds and rain have moved to the east and the weather will clear up, so "the sunset glow goes to Wan Li Road."

Scientific principle

Sunlight is a mixture of red, orange, yellow, green, cyan, blue and purple. The wavelengths of these colors of light are different. The red light wave is the longest, followed by the orange light wave, and the purple light wave is the shortest. Molecules in the air and countless tiny dust and water droplets float in the air, which can disperse various rays of the sun. This is called scattering.

The shorter the wavelength of light waves in the sun, the easier it is to scatter light such as purple and blue. The longer the wavelength, such as red and orange light, the less likely it is to scatter. In the morning or evening, the sunlight is oblique, and its distance through the air layer is relatively long, so the scattering is greatly weakened. The most attenuation is violet light, and the least attenuation is red light or orange light. These weakened colored sunlight shines on the sky and clouds, forming bright and dazzling rosy clouds.