Extraordinary Quadruple Rainbow Captured in Photograph
A photograph of a very rare quadruple rainbow was published online at LiveScience.com Thursday.
Only five such rainbows have been reported during the last 250 years.
Reports from LiveScience.com described the image as resembling a double rainbow since it only shows the third-order multi-colored arc in the sky along with the fourth-order rainbow.
These appear on the sunward side at approximately 40 and 45 degrees respectively from the sun.
The primary and secondary rainbows are located on the other side and cannot be seen in the new photograph.
Tertiary and quatenary rainbows are a result of the amalgamation of refraction, dispersion and reflection inside raindrops. While the processes that produce rainbows are all the same, they are taken to the maximum to produce these variations.
Refraction occurs when sunlight bends as it moves from air into water and vice versa. Water droplets bend each of the colors in sunlight by a slightly different angle. This is called dispersion, and it separates the colors to create a rainbow.
A large amount of that multicolored light passes through the other side of the raindrop, but some is reflected. This intense light is bright enough to create a visible primary rainbow.
A double rainbow takes place because not all that light exits the raindrop. A certain amount of this light is reflected back into the raindrop and goes through the entire procedure again. Although this light is dimmer, sometimes it is bright enough to produce a secondary rainbow just outside the first, according to the report at Yahoo News.
Raymond Lee, a professor of meteorology at the U.S. Naval Academy, has already made a prediction that tertiary rainbows might appear and challenged rainbow chasers to find them.
These popular optical rarities, caused by three reflections of each light ray within a raindrop, have finally been confirmed, thanks to photographic perseverance and a new meteorological model that provides the scientific underpinnings to find them, according to a published article in the Applied Optics Journal.