Why the sky is blue? The sky is blue because the molecules and atoms in the atmosphere scatter light from the sun. What is scattering? read more
Because sky and space are fundamentally different from each other. Sky is nothing but a thin layer of atmosphere around a planet while space is the rest of the void/vacuum, everything else basically. read more
For the same reason the sky is blue, the sky scatters blue light, while the redder light passes through unmolested. At dusk and dawn, you see the red light coming straight through to your position, because so much scattering is taking place that the blue light is no longer making it to you. read more