Twice in the past week I have seen the green flash.
The flash is a brief (blink and you'll miss it) ray of emerald green light that can sometimes be seen just at the top of the Sun's disk as the Sun sinks below the western horizon or rises in the east. It is caused by a combination of refraction and scattering in the Earth's atmosphere. To see it one needs a clear, flat horizon and atmospheric conditions have to be just right.
I started looking for the flash when I read an article about it in a 1965 issue of Scientific American, with a photo on the cover. For decades I pursued it, on three continents, at sunrise and sunset, fruitlessly. I told the story of the long search in Globe columns and Honey From Stone.
I might have been forgiven for thinking the flash was mythical, but, no, readers kept sending me photographs from all over the world, even inviting me to visit exotic locations where "we see the green flash all the time." (Today, photos and videos are all over the web.)
Then we came to Exuma, with a splendid sunrise horizon. I now see the green flash several times each winter. I never miss a sunrise.
Having spent so much of my life in a vain pursuit of the flash, it has become a kind of benediction -- if I may use a sacred term for a natural phenomenon -- a communication between whatever is deepest and most mysterious in the world and -- and me.
When I was an undergraduate at the University of Notre Dame, I would often go late at night to the replica of the Lourdes grotto to pray. I would focus my vision intently on just one random votive candle in the racks of flickering lights and whisper, "God, if you exist, let this candle go out now."
No candle was extinguished, but nevertheless my faith tottered on for some years more. Soon enough, as a student of the experimental method, I learned to distinguish coincidence from causality -- a confusion that is seemingly endemic in the human psyche.
I know the physical causes of the green flash, but it is rare and extraordinary enough to be the answer to a prayer: "God, if you exist, let the Sun rise in a blaze of green." And it is an answer to a kind of prayer, if prayer consists of silent attention to whatever is most beautiful and ephemeral in the world.