ESS55
Prof. Jin-Yi Yu
Scattering and Colors
qShort wavelengths (blue and violet) of visible light are scattered more effectively than are longer wavelengths (red, orange). Therefore, when the Sun is overhead, an observer can look in any direction and see predominantly blue light that was selectively scattered by the gases in the atmosphere.
qAt sunset,
the path of light must take through
the atmosphere is much longer.
Most of the blue light is scattered
before it reaches an observer.
Thus the Sun appears reddish in
color.
