These double bows at sunset are a study in red, a gorgeous pair of rainbows, and a lesson in optics.
This is photograph is something special. Captured at sunset on April 27th, 2014 by Manolis Thravalos from Samos Island, Greece, the sun was behind the camera. The list of optical phenomena is substantial: rainbows, red-tinted sunsets, and brightened sky within the bow.
Rainbows are formed when light catches raindrops just right for a million tiny prisms, splitting the white light into an arc of colour. The raindrops don't just split the light into rainbows; a portion is also directly reflected. This creates a brightened area below the primary bow. Rayleigh scattering through thicker atmosphere around the horizon means we only see the longest wavelengths, tinting the entire rainbow into sunset reds.