The sky was photographed just before the sun reaches the horizon(sunrise)which essentiallyis showing nothing but the breaking light on the tiny particles the air is made of. Here and there some clouds break the gradation of colors or pollution is muting the color saturation. The scattering of light through miniscule particles creates the color schemes visible to us at this time of the day but just like photography in general this surface is an illusion of color created by our eyes capacity of seeing blue lightwaves.
These images of the exotic or romantic depending who you talk to are purely made of the quintessence of photography, light.