Those who have ever followed the sunset to the very last moment, when the upper edge of the disk comes into contact with the horizon and then completely disappears, could see an amazing natural phenomenon. At this moment, the sun shone in clear weather and a clear sky casts its amazing last ray.
general information
For our eyes, the atmosphere is presented as a huge airy prism, facing down with its base. In the sun at the horizon it looks through a gas prism. Above, the solar disk receives a border of green and blue, and below - yellow-red.
At a time when the Sun is above the horizon, the light of the disk interrupts less bright multi-colored stripes with its brightness, so we do not notice them. However, when the Sun rises and sets, when the disk is almost hidden behind the horizon, you can see the blue border of its upper edge. Moreover, it is two-tone: below is a blue strip (from a mixture of green and blue rays), and above is blue.
What is the name of the flash of light at the moment the solar disk disappears? You can learn more about this optical phenomenon by reading this article.
A bit about the optical phenomena associated with the sun
The spectrum of sunlight, consisting of a huge variety of colors, is continuous. Violet, blue, blue and green rays have the property of refraction in the earth's atmosphere more strongly than red and yellow. This is due to the fact that the first rays that appear at sunrise (green and blue) are the last rays of the sun at sunset.
Due to its strong scattering, the blue ray is practically not observed in the atmosphere. The same green ray is an extremely rare phenomenon, manifesting itself as a green flash of light at the moment the sun disappears beyond the horizon or, conversely, when it appears over the horizon.
A rare natural phenomenon or optical illusion?
Many legends are composed about the famous magical "Green Ray" from the earliest times. These are mainly tales of happiness.
Many peoples have a tradition according to which those who see the "Green Ray" at the last moment of sunset, will forever find a rich and happy fate that brings only joy in life.
The lucky ones are more travelers and sailors. Even the famous writer Jules Verne in his novel entitled "Green Ray" presented a wonderful natural phenomenon. Many of his characters were eager to see this miracle, to become thanks to him the masters of fate and to possess huge treasures.
In many well-known cases, a green flash of light beyond the horizon appears for a short moment, like a fairy tale ghost.
The story of the Green Ray
There is a very curious story about the Green Ray, passing from generation to generation. She was once heard by a famous businessman and could not forget. It so happened that his business was greatly shaken. Nobody took his goods, so he was in deepest despair.
Once, trying all the ways to improve his position, he accidentally remembered that legend and went on a journey by sea to calm down and get the maximum benefit from pleasant impressions. There was also hope that it would be lucky to see the magical "Green Ray of Happiness" and get rich. He invited his friends on a trip, who agreed to a rather long voyage.
Every day they watched the sun go down. A week has passed, but no one has ever seen this miracle. Desperate, they had already stopped watching the sunset, but the businessman himself was patient with this lesson and did not miss a single evening. With an obsession, he went out onto the deck every night as a job.
A flash of light has occurred. His patience and perseverance were generously rewarded. A fabulously beautiful glow of green on the edge of the disk of the departing sun, he still saw. This spectacle caused him indescribable delight. He was in a real euphoric shock for a while, because he achieved his goal. Then, after the miracle he saw, he returned home, after which his affairs got better. And he connected all this with that very beautiful ray of happiness.
Literally after a short period of time, he became fabulously rich. Friends accompanying him on the journey began to regret that they were lazy and did not go on deck that significant evening. Apparently, the green happy ray illuminates the path only to the elect - persistent and patient.
What is a flash of light called?
The characteristic color of the sunset is due to the properties of refraction and scattering of sunlight in the atmospheric layers of the Earth.
Little is known about the optical phenomenon called the green ray. It occurs during sunset and is also associated with the passage of light in the earth's atmosphere. This is a unique natural phenomenon - the appearance of green light, which manifests itself in extremely rare cases and only in some places.
Where can I see?
For the most part, a green ray can be seen above the surface of the ocean or sea. It manifests itself only a moment. In central Russia, it can be observed extremely rarely and only with a combination of almost all favorable factors.
The most ideal place for observation, besides the water surface of the seas and oceans, can be the steppe, desert and mountains.
Conditions and Obstacles
To see a very rare unusual optical phenomenon with your own eyes, you need an open horizon, clean air and the absence of clouds. Such a miracle can be seen every day in the presence of all these conditions.
The main obstacle to observing a mysterious green ray is its scattering by suspended particles of dust, fog, smoke and other natural air pollution, as well as by inhomogeneities of airspace.
In addition to the above, the length from the point of entry of sunlight into the Earth’s atmosphere to the place of observation should be considerable, therefore, as noted above, it is best to observe a similar phenomenon at sunrise and sunset in vast water expanses.
A flash of green light in woodland and in the steppe is practically invisible.
In addition to the above conditions for detecting such an unusual phenomenon, there should be no upward convection flows in the atmosphere.
Origin
A flash of light lasts only a few seconds. At the moment of the disappearance of the solar circle, the so-called refraction of the sun's rays in the atmosphere occurs. The rays of light passing through the atmosphere, bending, are decomposed into several primary colors. This happens because the red rays are refracted less than the green and blue. In this case, the angle of refraction of the rays increases as the Sun approaches the horizon.
With a quiet calm state of the atmosphere, the “stretching” of the spectrum from the uppermost (violet) to red (lower) edge reaches 30 “. On such a long path through the lower atmospheric layers, a large mass of orange and yellow rays are absorbed by oxygen molecules and water vapor, while blue and violet rays are much weakened due to scattering. Therefore, mainly green and red remain, which leads to the fact that two discs of the Sun become visible, red (for the most part) and green, but they do not completely overlap each other. In this regard, at the very last moment, before the disk disappears beyond the horizon, precisely when its red part is completely below the horizon, the upper edge of the green strip is seen for a short time. In very clean air, a blue beam can also be seen. A green ray can also be seen at sunrise.
About the signs of a unique phenomenon
G. A. Tikhov (Pulkovo astronomer) devoted special investigations to the "green ray", thanks to which he identified some signs that make it possible to see this natural phenomenon.
1. If at sunset the sun has a reddish color and it is easy to observe it with a simple eye, then you can be sure that the green ray will not manifest itself. The reason for this is understandable: such a bright color of the disk indicates that there was a strong scattering in the atmosphere of green and blue rays (the entire upper border of the disk).
2. If the Sun does not change its usual whitish-yellow color and goes very bright beyond the horizon (this means that the absorption of rays in the atmospheric layers is small). In this case, there is a high probability that a flash of light will occur, you can see a green ray. But for this it is important that the horizon has a sharp even line, without buildings, forests, etc. Therefore, this beam is quite well known to many sailors.
Conclusion
In southern countries, the sky near the horizon is much more transparent than in more northern ones, therefore a flash of light ("green ray") is observed there more often. And in Russia it is not so rare that this happens, as many people think, perhaps under the influence of the writer Jules Verne.
In any case, the persistent and patient search for the "green ray" is rewarded with success. Some managed to capture this bewitching phenomenon even in a regular telescope.