The sky appears purple because of the way sunlight interacts with the atmosphere, especially when the sun is low on the horizon.
Understanding the Purple Sky Phenomenon
When the sun is low in the sky (during sunrise or sunset), the sunlight travels through a greater amount of atmosphere. This longer path causes the blue and violet light to scatter away, leaving the longer wavelengths, like red and orange, to dominate. According to the reference, this happens when the sun is low in the sky so that the light will pass through more air. The rosy hues of evening or dawn are superimposed on the scattered blue and violet light, creating a purple blend. This combination of scattered blue/violet light and the red/orange light results in the purple color we sometimes observe.
Factors Contributing to a Purple Sky:
- Sun's Position: Low sun angle at sunrise or sunset.
- Atmospheric Conditions: Presence of particles in the air (dust, pollutants) that scatter light.
- Scattering of Light: Blue and violet light scattered away, red and orange light dominating.
- Blending of Colors: Rosy hues superimposed on scattered blue/violet light.
