Why are sunrises and sunsets often orange or red?

During the evening and early morning, when the sun is lower in the horizon, the light that the sun emits has to travel through more of the atmosphere to reach us than it does during midday, when the path through the atmosphere is shorter. Since the distance through the atmosphere is much larger for sunlight in the morning and evening than during midday, more of the shorter wavelengths of light are scattered out of the direct light from the sun. Thus the sun’s color goes from yellow to orange and finally to red. Dust and water vapor in the atmosphere enhance this effect, making sunsets even redder.


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