Light rays in the sun

At sunset or sunrise, it can sometimes see how a portion of the visible sun above the horizon suddenly changes color, becoming an intense green. This unusual phenomenon - known as the "green radius" - is rarely seen and rarely could be photographed. Recently, however, Nigella Hillgarth, director of the Birch Aquarium at Scripps Oceanography Institute in San Diego, USA, has managed to "catch" the green radius in a superb shot.

The green radius usually lasts only a second or two and is due to complex optical phenomena that occur during the interaction between the sun's rays and the atmospheric air.At sunset or sunrise, it can sometimes see how a portion of the visible sun above the horizon suddenly changes color, becoming an intense green. This unusual phenomenon - known as the "green radius" - is rarely seen and rarely could be photographed. Recently, however, Nigella Hillgarth, director of the Birch Aquarium at Scripps Oceanography Institute in San Diego, USA, has managed to "catch" the green radius in a superb shot.The green radius usually lasts only a second or two and is due to complex optical phenomena that occur during the interaction between the sun's rays and the atmospheric air.Nigella Hillgarth certainly has one of the most beautiful photos of the "green beam" ever made.
Atomosphere acts as a prism that decomposes sunlight in different colors (bright radiations with different wavelengths). When the solar disc is completely visible above the horizon, different colors of light overlap in such a way that they can not be individually distinguished with the naked eye.
But as the sun falls below the horizon, the spectrum colors disappear one by one, starting with the ones with the highest wavelength and ending with the low wavelengths. At sunrise, the process unfolds, the colors "appearing" in a row below the horizon.Usually, the green radius is the one that draws attention, in contrast to the red, the orange and the yellow that usually accompany the sunrise and sunset. Rarely, when the air is very clear, the blue and violet rays also pass through the atmosphere, producing a short glow in these colors. However, green is more often seen and surprised in photos.The green ray can appear in several forms, most often two optical phenomena: inferior mirage (about two-thirds of the observed green ray) and false mirage.

The inferior mirage produces an oval and flat image that appears close to the surface of the sea when its surface is warmer than the top air.

The false mirage appears higher in the sky when the surface is cooler than the air above it, and it has the appearance of "sun strips".It is most likely that the green radius is observed in areas with a wide view, open to the horizon, in very serene weather, in areas with unpolluted air.

The picture was used by Jules Verne in his novel Raza Green, whose heroes take a long journey to see this rare phenomenon.