When the sun is low in the sky at sunrise or sunset, you’re seeing it straight-on through a great distance of atmosphere.
While traversing all that atmosphere, a lot of the blue light that started out in your direction gets scattered into many other directions, so the light that reaches you straight-on is depleted in blue.
Sunlight that is depleted in blue looks red, orange or yellow, depending on what size particles of dust happen to be in the air, and what other colors they are therefore scattering. If that kills the romance, forget that I ever said anything.
Make your own sunset.
Add a few drops of milk to a clear glass of water and look through the glass at a light bulb. The bulb will look red, yellow or orange. The light coming to you from the bulb is depleted in blue because of scattering from the tiny casein particles and butterfat globules suspended in the milk.
The exact color that you see depends on the size and concentration of these particles in the water.
