Open Question: Why does planet earth's sky appear to be the color blue?

Open Question: Why does planet earth's sky appear to be the color blue?

It's due to scattering of light.

When you look at the sun, it's yellowish because you are looking at it head on.

When you look at the sky, you are looking at indirect light. That is light that is coming in perpendicular to your sight and then it scatters in the perpendicular direction (towards your eye).

Longer wavelengths scatter more forward (i.e. when you look directly at the sun) and shorter wavelengths scatter more in the perpendicular direction (i.e. when you look away from the sun at the sky).

Therefore more blue light scatters in the perpendicular direction and more red light scatters in the forward direction.

You can read this wiki article for more details:

http://en.wikipedia.org/wiki/Rayleigh_scattering

Edit:

Conversely, this also explains the red when the sun is setting/rising. When you see the sun setting, the sun's light has to go through A LOT of the atmosphere, since you're seeing mostly the forward scattering you see more red/orange (longer wavelengths).


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Open Question: How far down is the Earth's core? How hot is it down there?
Open Question: Physics!:How much energy is stored in 0.955 m3 of Earth’s atmosphere?

Open Question: Physics!:How much energy is stored in 0.955 m3 of Earth’s atmosphere?

Home >All Categories > Science & Mathematics >Physics >Open QuestionKing King Member since:January 21, 2007Total points:80 (Level 1)Near the surface of the Earth, the magni-
tude of the Earth’s magnetic field is about
4.32 × 10-5 T.
The permeability of free space is 4pi×
10-7 T · N/A.
How much energy is stored in 0.955 m3 of
Earth’s atmosphere?
Answer in units of J.Answer Question

Be the first to answer this question.


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