You must have seen the bright shining sun changing to red color many times. Often this happens when the sun rises and sets. The sun turns red, the sky turns orange, dark red or purple. But in reality there are completely scientific reasons behind it. The answer is 'scattering'.
In the 19th century, British physicist Lord Reilly was the first person to explain the incident of light scattering. The scattering of light is the process in which when sunlight comes out into the atmosphere, then dust and soil particles collide and spread around.
Near the horizon, sunlight passes through thicker layers of air having larger particles that scatter light of longer wavelength such as the red end of the spectrum. Also, it travels a larger distance at the horizon before reaching the earth. However, light from the Sun overhead travels a relatively shorter distance. At noon, the Sun appears white as only a little of the blue colour is scattered whereas, near the horizon, most of the light of shorter wavelength at the blue end of the spectrum is scattered away by the small particles of the atmosphere. Therefore, the light that reaches our eyes is of a longer wavelength which gives rise to the reddish appearance of the Sun.