Contradictory: Sky blue and sunset red?

[Pranav Jha]

Sky is supposed to blue during the day because of maximum scattering of violet and blue light. But if they get scattered in the sky, how do they reach our eyes? With this logic i think the sky should be yellowish red during the day (which it surely isn't!)
With this notion i can understand why sunsets are red as most blue light has been scattered and the majority of visible light reaching our eyes is red.
So, what is amiss with my understanding here?

 

[Dale]

Scattered light still reaches our eyes, just from a different direction. You are confusing scattering and absorbing.

 

[Pranav Jha]

duh! Indeed, I was confusing the two terms

 

[D H]

Scattered light still reaches our eyes, just from a different direction. You are confusing scattering and absorbing.

There is no confusing of scattering and absorbing here. Just confusion. Rayleigh scattering explains both red sunsets and blue skies. There is no need to invoke the concept of absorption.

Pranav Jha, think of it as a one person's gain and another person's loss. Those blue photons you see when you look at the sky are blue photons that someone else did not see when they looked at the sunset.

 

[Pranav Jha]

Pranav Jha, think of it as a one person's gain and another person's loss. Those blue photons you see when you look at the sky are blue photons that someone else did not see when they looked at the sunset.

i don't get what you mean

 

[D H]

Suppose that Rayleigh scattering did not occur. Were that the case, our sky would be black rather than blue and the sun would appear to be the same color all day long.

Rayleigh scattering however does occur. You see a blue sky because the sky selectively scatters blue photons. Let's focus on one such photon. This photon came from the Sun, but the at a slightly different angle from the line between the Sun and you. Let's trace where that blue photon would have gone had it not been scattered. There are three possibilities: It would either have gone back out into space, it would have hit the Earth somewhere, or it would have hit someone's retina who was watching the sunset.

That the sky is blue inherently means that the Sun has to be red at sunset. There is no contradiction here.