Below is a phenomena I have seen only in my so-called "Secret Camp," which I learned this week, can be attributed to the fact that only in this location am I likely to be looking many miles east during a sunset.
I thought that the sky was blue at the horizon, and pink above, because the scattering of the long rays of the setting sun simply didn’t reach the horizon. But no! A meterologist explains it this way:
Looking WEST you see the effects of scattering with blue skies above the reddening (pink) sunset sky near the horizon as only the longer wavelengths (red) reach our eyes through the denser air near the surface. Looking EAST, the sunlight is also scattered, changing from blue to the longer wavelength (reddish or pink). Then below that is the rising shadow of the earth against the sky called the twilight wedge, again bluish.
Got that? Let me put it this way: it’s easier to remember than to explain: