LE RAYON VERT

“Le Rayon Vert” is French for the Green Ray, although most people call it the Green Flash. It is a real optical phenomenon that can be seen at either sunset or sunrise. It takes the form of a sudden burst of green light shooting upward from the horizon.

So seldom were people able to catch a glimpse of the “Green Flash” that it was thought to be something mystical until the mid-nineteenth century. Writer Jules Verne knew about the flash and used it as a theme in his novel “Le Rayon Vert” in 1882. His characters included a pair of lovers who were attempting to view the green flash while in Scotland. They were continuously frustrated by conditions. Finally, the flash was clearly visible one evening but, because the two were so in love, they only looked into each

other’s eyes; and they missed it.

Verne described the flash as “a green which no artist could ever obtain on his palette, a green of which neither the varied tints of vegetation nor the shades of the most limpid sea could ever produce the like! If there is a green in Paradise, it cannot be but of this shade, which most surely is the true green of Hope.”

There is also an old Scottish legend about the green flash. It says that “someone who has seen the flash is incapable of being deceived. They are enabled to see closely into their own heart and to read the thoughts of others.”

But what causes it? If you look at a bright star through a telescope, instead of a pinpoint of white light it will appear as a spectrum with bands of color ranging from blue to green to yellow to red.  A similar effect occurs with our Sun as it sets (and rises). At sunset the red of the Sun disappears first as its light is bent the least. The yellow and orange bands are absorbed by ozone. The blue, indigo, and violet bands are almost never seen because they are scattered by our atmosphere. The last color band that can be seen is green. When the Sun rises, the bands are displayed in the same way although in reverse order - the green band is the first to be seen.

The green flash phenomenon can appear either as flattened oval shape that is pinched off or, more impressively, a burst of green light shooting upward. I have spent many sunsets standing on the shore line to see the green flash but as yet I’ve been unsuccessful. There are many things that can happen to hide the flash - clouds, haze, passing ships. And if the conditions are right, the green flash will only last about 1.4 seconds on average. If you get distracted, which I always do, you could miss it altogether.

Here are some tips for seeing the green flash. Your best hope for seeing the flash is to look for it on a clear night (or morning) just as the sun is at the horizon. Clouds can scatter the light and ruin the effect. In addition to the sea shore, being on a tall building, a mountain, or in an airplane is also good. The green can be seen only after the red image is gone (if in the evening). A good alternative is to view the planets of Venus and Jupiter with a telescope as they pass below the horizon. The Moon also exhibits a slight green flash.

There is an associated phenomenon called a “green rim” where the outer edges of a bright object will turn different colors as the object sets or rises in the sky. The lower rim is always red because our atmosphere is denser closer to the horizon; the upper rim is likely to be green or blue because of the decrease of particulates in the atmosphere. The longest recorded duration of a green rim occurred in 1935 in Antarctica when members of the Byrd Expedition experienced it for 35 minutes. A green rim can sometimes transform into a green flash as the object sets below the horizon.

Try your luck at seeing the elusive green flash but don’t get frustrated if it takes a few attempts. I have been trying my entire life. Well, there will always be another sunset tomorrow.