Why does the rising and setting Sun appear red?

When the Sun rises in the east, it appears like a red ball. As the day advances, its colour appears white, but again at the time of sunset in the evening, it appears red. Do you know why is it so? We know that the blanket of air called atmosphere surrounds our Earth. Sunlight passes through the atmosphere before it reaches us. We also know that sunlight is composed of seven colours — violet, indigo, blue, green, yellow, orange and red. In the mornings and evenings, when the Sun is near the horizon, the rays travel about 50 times longer a path in the atmosphere to reach us than they do in the noon. The dust, smoke and water vapour present in the atmosphere scatter away these colours differently. Violet, indigo and blue are scattered most and red and orange are scattered least. That is why most of these two colours reach our eyes. As a result, the rising and setting Sun appears red.