While shooting a sunset in New Jersey, photographer John Entwistle observed a magnificent picture: a sky colored with five rainbows!
Unusual rainbows like this are made up of a primary rainbow - the brightest - plus at least two others. Multiple rainbows are quite common, according to retired climatologist Gunther Kennen of the Royal Netherlands Meteorological Institute. There are many pictures where you can see two or three, but five rainbows at once is an exceptional event.
Raymond Lee, a research professor at the US Naval Academy in Annapolis, agreed, noting that multiple rainbows are an integral part of any rainbow. Despite this, they are difficult to see because they are not as bright as the main parent arc - they tend to be hidden behind the bright colors of the primary rainbow.
The two types of rainbows form roughly the same, with one difference. A basic rainbow is formed when sunlight hits a drop of water and then refracts. As different wavelengths of light bend in different amounts, and the process takes place in a large number of tiny droplets, you see a rainbow. Multiple rainbows form due to interference between light waves that follow slightly different paths within the droplet. Multiple rainbows are more likely to be seen when the raindrops are relatively uniform in size, as light rays that pass through the raindrop are more likely to create colors. With droplets of different sizes, light waves are more likely to cancel each other out, which means no light and multiple rainbows.
In this image, the rainbows are conical - this means that the mutual distance between the rainbows is less at the horizon than at the top. Lee stressed that if you have not seen multiple rainbows before, then you should just look at the pictures with them to understand how they look. After that, you will begin to notice them constantly in many different rainbows.