"Closer to the horizon, the sky fades to a lighter blue or white. The
sunlight reaching us from low in the sky has passed through even more air
than the sunlight reaching us from overhead. As the sunlight has passed
through all this air, the air molecules have scattered and rescattered the
blue light many times in many directions. Also, the surface of Earth has
reflected and scattered the light. All this scattering mixes the colors
together again so we see more white and less blue."
-----Original Message-----
From: Bob Sciamanda
Sent: Sunday, August 18, 2013 10:50 PM
To: PHYS-L
Subject: [Phys-L] Where is the sky?
How is it that the blue sky of scattered sunlight appears to come from a
highly localized source confined to a distant hemispherical surface? Does
not the entire atmosphere participate in this scattering?