Optical Scatter Page
(all photographs by J. Gerencher)

Scatter affects blue light more than red light, causing both the blue sky and the red sunset.  The more air involved with the light path, the greater the scatter.  The light path near sunset involves much more air than the light path near noon, so the amount of scatter is greater near sunset, significantly modifying both the color and the intensity of the light.

Red sky at sunset, Bethlehem, PA.
Sunset seen from roof of Collier Hall of Science,
Moravian College, Bethlehem, PA.
Martin Tower is right of center in the photograph.

Reflected versus direct rays, seen from airplane.
Low sun reflecting from ocean surface off New Jersey coast.
Note how reflected light is redder than direct light from sun
because reflected light path involves more air than direct light.

Red reflected sunlight near sunset, Greece.
Sunset reflected from ocean surface,
with reflection redder than direct path.
Nauflion, Peloponnesus, Greece.