Why does the sun appear red during the sunrise and the sunset?
All of the above.
The visible light’s rays are white and consist of seven colours – violet, indigo, blue, green, yellow, orange and red (known simply as VIBGYOR). The earth’s dust, gas and air particles scatter the sun’s light in different directions. Violet light has a peculiar property due to which it gets scattered the most. Red light gets scattered the least. At sunrise, the earth is rotating towards the sun. Similarly, during sunset, the earth is rotating away from the sun. During these times, the sunlight has to travel at an angle and thus cover a longer distance through the atmosphere. It encounters more obstacles in its path. Most of the colours, like green and violet, get scattered before the light reaches the earth. Since red is scattered the least, it is this colour that we see as it reaches us.