Open Question: Why does planet earth's sky appear to be the color blue?
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).
Open Question: Water has no color why?
by Greg Member since:April 08, 2011Total points:102 (Level 1)Water does have colour - blue. It's just so weak that you don't see it unless it is in large abundance such as in oceans or lakes. The reason? Because of the way that the bonding in the water interacts with light. It's not merely a reflection of the sky.
