Sunset – extraordinary beautiful and pacifying show. Inspired by this phenomenon, artists create fine cloths, photographers - delightful shots. Scientists explain red color of a sunset with physical properties of a certain length of the light wave perceived by a human eye.
Sunlight passes deep layers of air before reaching the earth. The color light spectrum is extremely wide, however in it it is possible to mark out seven primary colors, from red to violet which are the main flowers of a range. The color seen by an eye is explained by length of a light wave. Respectively, red color gives the longest light wave, and violet – the shortest.
During a decline of people can observe the disk of the sun which is quickly coming to the line of the horizon. At the same time sunlight passes through the increasing thickness of atmospheric air. The more length of a light wave, the less it is subject to absorption by an atmospheric layer and aerosol suspensions which are present at it. That to explain this phenomenon, it is necessary to consider physical properties of blue and red colors, habitual shades of the sky.
When the sun is in a zenith, the observer can tell that the sky blue. It is connected with differences in optical properties of blue and red colors, namely abilities to dispersion and absorption. Blue color is absorbed stronger red, however its ability to dispersion is much (four times) higher than similar ability of red color. The wavelength attitude towards intensity of light – the proved physical regularity having the name "Rayleigh law of the blue sky". When the sun is highly, the layer of the atmosphere and suspensions separating the sky from eyes of the observer rather small, the short wave of blue color is not absorbed completely, and the high ability to dispersion "muffles" other colors. Therefore in the afternoon the sky seems blue. When there comes sunset time, the sun begins to fall promptly to the line of the true horizon, and the atmosphere layer sharply increases. After certain time the layer becomes so dense that blue color is almost completely absorbed, and red color thanks to high resistance to absorption comes to the forefront. Thus, at sunset the sky and a star seems to a human eye in various shades red, from orange to bright red. It should be noted that the same is at sunrise observed and for the same reasons.