What is the green flash and where can you see it
Geographical phenomena #2: Green flash
The remarkable explained
By
If you ever find yourself with an uninterrupted view of the horizon at sunset or sunrise on an exceptionally clear day, you might, if you’re very lucky, catch a glimpse of a rare spectacle: the so-called green flash, when, for just a second or two, the upper edge of the sun becomes bathed in a vivid green hue. Many believe the elusive marvel is a myth or the sort of story beach bartenders use to persuade you to buy another drink.
However, there is a scientific explanation. When sunlight passes through a prism, it refracts, revealing the rainbow of colours exhibited by its differing wavelengths. The red and orange light has the longest wavelengths, so they’re more penetrating and are what we see when the sun is low in the sky and the Earth’s atmosphere acts as a prism. The blue and green light’s wavelengths are at the other end of the spectrum and tend not to be visible.
Occasionally, a burst of the green can be seen just above the sun. A mirage effect caused by temperature differences in the atmosphere that can intensify the separation of colours and create the elusive green flash when the sun is near the horizon. It lasts for a mere blink of an eye.
Jules Verne was captivated by the phenomenon – so much so, that he wrote what turned out to be one of his least popular novels, Le Rayon Vert, in 1882. His charming conceit was that the green ray gives the viewer a heightened perception, allowing them to fully understand their feelings and those of others. The protagonists are a young couple who go chasing the green flash across Scotland. Verne’s love story formed the inspiration for Éric Rohmer’s 1986 film The Green Ray.
Because the Sun’s relative motion is slightly slower for airline pilots flying west over the Atlantic, they’re more likely to see the green flash than anyone else.
