My question is if more light is getting scattered as light travels from just above the horizon to an observer, wouldn't the sky appear darker rather than lighter at that point? The fact that it is light implies that there is more light, not less, reaching you.
How can this be if the sun is directly overhead and there is no other source of light in that direction?
I have an idea, but I would like to first see what others say.
The horizon is pale blue because that is where the blue light is scattered the least. When light is scattered, it is more likely to scatter at shallow angles (light is less likely to scatter at 90 degrees than it is to scatter at, say, 10 degrees). The sky will display the most scattering in the region directly around the sun itself. In other words, during midday, the area surrounding the sun is the blue-est. The horizon is the furthest area from the sun at midday, and therefore displays the least scattering.
When the sun itself is on the horizon, the sun's light is filtered through a greater amount of the Earth's atmosphere. At the point where you see the sun's light, most of the blue has been already scattered, and this is why the sun appears to be red/orange.
Any more questions?
light in the tunnel
20th September 2009 - 10:15 AM
QUOTE (flyingbuttressman+Sep 20 2009, 02:55 AM)
Any more questions?
Are there any tests that prove these explanations? Or are they just the most logical?
flyingbuttressman
20th September 2009 - 03:14 PM
QUOTE (light in the tunnel+Sep 20 2009, 06:15 AM)
Are there any tests that prove these explanations? Or are they just the most logical?
My original statement was slightly off in that the effect is dipole scattering, this means that the scattered photon is most likely to scatter forwards or backwards, but is least likely to scatter at right angles.
Blue Sky and Rayleigh Scattering.
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