The scattering of light is the phenomenon by which a beam of light is redirected in different directions on interacting with the particles present in the medium. The scattered light's colour depends on the size of the scattering particles. The particles of very small size scatter mainly blue light whereas, the particles of larger size scatter lights of longer wavelengths. The sky appears blue because the fine particles in the atmosphere scatter blue light the most among all the components of white light. At sunrise, the Sun is located near the horizon. Hence, the light has to travel a long distance through the Earth’s atmosphere. At the time of sunrise or sunset, when white sunlight falls on suspended atmospheric particles, the blue colour light scatters out in the atmosphere, while the red colour light scatters less and reaches the eyes of the observer on the surface of the Earth. Hence, when this less scattered red light reaches eyes of the observer, the Sun and its surroundings appear reddish.