Question map
The Sun appears reddish during sunrise and sunset. The phenomenon in optics which is responsible for this appearance of the Sun is
Explanation
The reddish appearance of the Sun during sunrise and sunset is primarily due to the phenomenon of scattering, specifically Rayleigh scattering [1]. Sunlight consists of various wavelengths; shorter wavelengths (blue and violet) are scattered more effectively by nitrogen and oxygen molecules in the atmosphere. During sunrise and sunset, sunlight travels a much longer path through the atmosphere to reach the observer. This extended path causes the shorter blue wavelengths to be almost completely scattered away from the line of sight. Consequently, only the longer wavelengths, such as red and orange, penetrate the atmosphere and reach our eyes. While larger particles like dust and aerosols can also contribute through Mie scattering, the fundamental optical process responsible for the color shift is the selective scattering of light [1].
Sources
- [1] Physical Geography by PMF IAS, Manjunath Thamminidi, PMF IAS (1st ed.) > Chapter 20: Earths Atmosphere > Solid Particles > p. 273