This was sunset viewed from our window two days ago.
That red cloud was such a sight to behold.
I did some research to find out why the autumn and winter sunsets are so vivid.
During sunrise and sunset the light of the sun must pass more of our atmosphere to reach our eyes. In the process it comes in contact with more molecules in the air.
Blue light gets scattered easiest by air molecules, nitrogen and oxygen, because it has a shorter wavelength.
You can see a little area of blue sky to the left, in the middle of the photo.
Reds and oranges have longer wavelength light and aren't as easily scattered by air molecules.
Much of the blue light gets scattered away, while the reds and oranges are more pronounced.