The Green Flash

Ah, the Green Flash - the mystery, the wonder, the quest. After watching decades of sunsets, I finally saw a Green Flash. And, yes, I deem it worthy of capitalization because it is a marvel, like a god, that many pursue and only a few witness. I know the Green Flash is a simple optical refraction phenomenon, not an illusion, but I was still pretty stoked and doubly excited because I was looking through a camera lens and snapped a picture of this rara avis. Now I can prove to friends that this wonder was truly physical and not physiological, psychological, or a figment of a Mai Tai.

We have all heard sailors and old timers wax on about the beauty of the Green Flash; they say it is a brilliant emerald color not seen in any artist’s palette. I always assumed that the people who claimed to see it fell into one of several categories: those who habitually see pink elephants; those who have stared at the sun so long they have destroyed the retinal rods that transmit any color other than green; and those who lie about what they have seen in order to score deference, dates, or drinks.

From a scientist’s perspective, the Green Flash is a phenomenon due to the dispersion of atmospheric refraction. As the sun drops below the horizon, the shorter wavelength green light has a longer refractive delay and hence is the last to disappear - which is really a good thing if you like Green Flashes. Now the astute reader will be saying, “But blue is an even shorter wavelength than green so why don’t we get a blue flash?” The very short wavelength blue light of the setting sun is scattered away by air molecules and aerosol particles before it gets to your eye. That’s why the sky is blue.

From a nonscientific perspective, observing Green Flashes is a result of people relaxing and watching the sunset regularly enough that they get treated to a nonpareil vision - sort of the visual equivalent of stopping to smell the roses.

Jules Verne was so enamored by the Green Ray, as he called it, that he wrote the novel Le Rayon Verte, a story of people traveling to Scotland in quest of the Green Flash. At the end of his novel, they prevail. Verne’s description¹ of the event is:

Motionless, and with intense excitement, they watched the fiery globe  as it sank  nearer and nearer the horizon, and,  for  an   instant,  hung   suspended  over  the  abyss. Then, through the refraction of the rays, its disk seemed to change till it looked like an Etruscan vase, with bulging sides, standing on the   water. There was no longer any doubt as to the appearance of the phenomenon. Nothing could now interfere with this glorious sunset! Nothing could prevent its last ray from being seen! ... At last only a faint rim of gold skimmed the surface of the sea.

"The Green   Ray! the  Green Ray!" cried  in  one breath  the  brothers,  Dame  Bess and  Partridge,  whose eyes for one second had reveled in the incomparable tint of liquid jade.

Since Jules Verne wrote this so well in 1882, all I can add to it is the picture I took. Alas, I did not get a photo of the Etruscan vase - maybe next time.  

The Green Flash - Pacific Ocean off the coast of Baja California

Right before the flash - almost an Etruscan vase.

1 – Jules Verne, The Green Ray, 1882. Translated from the French Le Rayon Vert by Mary De Hautesville. Published by Sampson Low, Marston, Searle, & Rivington; London, 1883. Copy obtained via The Internet Archive. http://www.archive.org/details/greenraytrbymde00verngoog