Jules Verne. Green Ray

Basically, the lucky ones who had the opportunity to see this are sailors. They believe that his appearance is a good omen, a sign of a successful completion of the journey. People believed that the one who saw the green beam would find his happiness. Bright flashes of blue-green color, at the edge of the Sun, leave indelible impressions and memories for a lifetime.

Skeptics consider the green beam to be fiction or an optical illusion. Some believe that this is the reaction of the human eye, tired of contemplating the sun. It is for the latter that the famous popularizer of science Ya. I. Perelman in his book "Entertaining Physics" not only explains in detail the cause of the natural phenomenon "green ray", but also cites facts that refute various misconceptions about this. And in our time, when photographic technology makes it possible to capture numerous cases of the appearance of a green beam, it seems that doubts should leave skeptics.

The reasons for this extraordinary spectacle can be easily explained based on the knowledge gained in high school. It is known that sunlight consists of a set of electromagnetic waves, each of which has its own frequency and length. A wave of a certain frequency is perceived by the human eye as a color: red, orange, yellow, green, blue, indigo and violet (every hunter wants to know where the pheasant is sitting). Red color has the largest wavelength in this spectrum, which is about 0.7-0.6 micrometers. For green and violet colors, the wavelength is approximately 0.5 and 0.4 micrometers, respectively. Despite such seemingly small differences in wavelength, rays of different colors propagate differently in matter, in particular, they have different speeds. The dependence of the speed of light waves in a substance on their length or frequency is a manifestation of a more general dependence of the speed of the response of a substance to the frequency of oscillations of the electric field in a light wave. In physics, this phenomenon is called dispersion. In most substances and environments, including the earth's atmosphere, red light propagates at a higher speed than blue-green. This dependence, called normal dispersion, corresponds to lower refractive indices for red light than for blue-green. Recall that the refractive index is a value showing how much the speed of light in a substance v is less than in vacuum: n = c/v, where c ≈ 3.108 m/s is the speed of light in vacuum.

And if you also know the law of refraction of light, everything is generally simple. According to this law, with an oblique incidence of light on the boundary of media with different refractive indices, the light beam deviates from the original direction of propagation, that is, it is refracted. When a light beam hits from a region with a smaller value of n, for example, from a vacuum, where n = 1, into a medium with a larger value of n, the angle of refraction is always less than the angle of incidence. Recall that both angles are measured from the normal (perpendicular) to the interface between the regions. Since the refractive indices for waves of different lengths are different, the angles of refraction will also be different, namely: red light will be refracted less than green. This, in particular, is the reason for the decomposition of white light into a spectrum when it is passed through a glass prism. A similar decomposition of sunlight into a spectrum takes place in the Earth's atmosphere. However, it is observed only in individual cases and in special places. So, at sunset or sunrise, its rays, visible to an observer on Earth, fall obliquely from outer space (vacuum). Since the density of the atmosphere increases as you approach the surface of the Earth, the refractive index of light also increases. Light, propagating from space to the earth's surface, is constantly refracted, and therefore decomposed into a spectrum, and, as in a glass prism, the rays of red light are refracted least of all. Although the difference in the refractive indices for red and blue-green light rays in the atmosphere is extremely small, but at large distances (hundreds of kilometers), the effect of their separation is quite observable. This is precisely the reason for the appearance of the green beam. Indeed, while the sun is already actually below the horizon and its red rays pass above the observer, the shorter wavelength green rays, which are more deflected, can be seen. Of course, blue, blue and violet rays, which have an even shorter wavelength, are refracted much more strongly, but it is almost impossible to see them: they are very strongly scattered and absorbed in the earth's atmosphere.

The main obstacle to observing the green beam is scattering on suspended particles of fog, dust, smoke and other terrestrial air pollution, as well as on atmospheric inhomogeneities. In addition, as already mentioned, the length of the path of sunlight from the point of entry into the Earth's atmosphere to the point of observation must be sufficiently long. All these conditions are most easily met when observing a sunset or sunrise over large expanses of water. It is almost impossible to see a green beam in the steppe or in a wooded area. Even understanding all the physical causes and the natural origin of the green ray, it is difficult to get rid of a strong emotional impact. Therefore, like sailors and poets, I would like to believe that the appearance of this miracle of nature will serve as a good omen for the country and the people living in it.

Most often, the solar disk looks familiar to us: blinding bright white during the day, it turns red in the morning and evening.

The green beam, also called green lightning, can only be seen by chance. Here is a description of an eyewitness of such a phenomenon. Fuerteventura in the Canary Islands, early January 1995. I got up early to watch the sunrise on the beach. Soon, a luminary rose above the sea horizon in the east, but not gradually, as it always happens, but suddenly, as if someone unseen had flipped a switch. I was surprised, but even more struck by the emerald green tones that were visible for several seconds on the upper edge of the sun. Was it the same famous and rare green ray, about which the Scottish legend says that a person who once saw it would never again be mistaken in his feelings?

The ancient Egyptians, who revered the Sun as a deity, depicted green rays on a stone stele 4 thousand years ago, and the French writer Jules Very dedicated to them the novel The Green Ray, atypical for his work, and described the beauty of this phenomenon in sublime tones: “If there is a green color in paradise, it cannot be otherwise, for it is the true flower of hope.”

However, such higher pleasure can be received not only by "early birds"; a short and colorful spectacle can also take place at sunset, shortly before the luminary disappears over the horizon. But this requires appropriate conditions - a clear horizon, not covered by clouds, and transparent air. Most often this happens at sea and on the coast.

The explanation for this impressive spectacle is the simplest: the scattering and refraction of light in the atmosphere. Many other colorful celestial phenomena are associated with them, including the rainbow.

As you know, sunlight consists of light rays with different wavelengths corresponding to different colors. Violet light has the shortest wavelength, followed by blue, cyan, green, yellow, orange, and finally red long wavelength light. Passing through a layered atmosphere, light is refracted, but the angle of refraction depends on the wavelength: the shorter the wavelength, the stronger the refraction. Thus, it turns out that the strongest refraction is experienced by violet and blue rays, and the least by red ones. But light is not only refracted in the layers of the atmosphere, but also scattered by air. Moreover, mainly violet and blue rays are scattered. There are two obvious consequences of this: the blue color of the sky and the orange-red color of the sun at the horizon. As the sun descends towards the horizon, the differences in refraction begin to show up as a narrow green border appears at the top edge of the orange-red disk, while a bright red border appears at the bottom edge. And now the sun has almost disappeared behind the horizon, and at this moment only a green border remains visible - a green beam. At sunrise, everything happens in the reverse order: first, a green beam flashes and then the luminary itself appears.

Especially impressive is the phenomenon of green surf, which is sometimes observed in the oceans. A green beam for a few moments turns the foamy wave crests near the horizon green.

In a word, the green beam is not such a rare phenomenon as it is believed. It is only necessary to have accurate information, namely to know when and to know where. That is, to know the time of sunrise or sunset to the nearest second, and it is best to go to the Arctic or Antarctic (for those who can afford it). When the Sun first appears after the long polar night and moves along the horizon, the green beam can be observed for a longer time. During one of the expeditions to Antarctica, the American polar explorer Richard Byrd admired it for 35 minutes.

Refracted sunlight. The sun's rays that enter the Earth's atmosphere at an acute angle do not pass through it in a straight line, but are refracted and break up into a spectrum of colors. At a certain point in time at sunset, only green light is visible.

green beam- an optical phenomenon, a flash of green light at the moment the solar disk disappears behind the horizon (usually sea) or it appears from behind the horizon.

"Have you ever observed the Sun setting below the horizon of the sea? Yes, without a doubt. Have you followed it until the moment when the upper edge of the disk touches the horizon and then disappears? Probably yes. But have you noticed the phenomenon what happens at the moment when the luminous luminary throws its last ray, if the sky is cloud-free and completely transparent? a color such that no artist can obtain on his palette and that nature itself does not reproduce, either in the various shades of vegetation, or in the color of the most transparent sea.

An article in an English newspaper from Jules Verne's novel "The Green Ray"

Such a note brought the young heroine of Jules Verne's novel "The Green Ray" into an enthusiastic state and prompted her to undertake a series of journeys with the sole purpose of seeing the green beam with her own eyes. The young Scot failed, as the novelist says, to observe this beautiful natural phenomenon. But it still exists. The green beam is not a legend, although there is a lot of legend associated with it. This is a phenomenon that every nature lover can admire if he searches for it with due patience. Why does the green beam appear?
You will understand the cause of the phenomenon if you remember in what form objects appear to us when we look at them through a glass prism. Do this experiment: hold the prism near the eye horizontally with the wide side down and look through it at a piece of paper pinned to the wall. You will notice that the leaf, firstly, has risen much higher than its true position, and secondly, it has a violet-blue border at the top, and a yellow-red one at the bottom. The rise depends on the refraction of light, the colored borders - on the dispersion of glass, i.e. the properties of glass to refract rays of different colors unequally. Violet and blue rays are refracted more strongly than others, so we see a violet-blue border at the top; red ones are refracted the weakest, and therefore the lower edge of our paper sheet has a red border.

For a better understanding of what follows, it is necessary to dwell on the origin of these colored borders. The prism decomposes the white light emanating from the paper into all the colors of the spectrum, giving many color images of the paper sheet, arranged, partly superimposed on one another, in the order of refraction. From the simultaneous action of these superimposed. On top of each other of color images, the eyes get a sense of white color (the addition of spectral colors), but at the top and bottom there are rims of immiscible colors.

The famous poet Goethe, who did this experiment and did not understand its meaning, imagined that he had thus exposed the falsity of Newton's doctrine of colors, and then wrote his own "Science of Flowers", which is almost entirely based on false ideas.

The earth's atmosphere is for our eyes like a huge air prism, turned base down. Looking at the Sun at the horizon, we look at it through a gas prism. The disk of the Sun receives a border of blue and green at the top, and red-yellow at the bottom. As long as the Sun is above the horizon, the light of the disk interrupts much less bright colored stripes with its brightness, and we do not notice them at all. But at the moments of sunrise and sunset, when almost its entire disk is hidden under the horizon, we can see the blue border of the upper edge. It is two-tone: above is a blue stripe, below - blue, from a mixture of blue and green rays. When the air near the horizon is completely clear and transparent, we see a blue border - the "blue ray". But more often the blue rays are scattered by the atmosphere and only one green border remains: the "green ray" phenomenon. Finally, in most cases, blue and green rays are also scattered by the cloudy atmosphere - then no border is noticed: the Sun sets in a crimson ball.

Pulkovo astronomer G. A. Tikhov, who devoted a special study to the "green ray", reports some signs of the visibility of this phenomenon. " If the Sun is red at sunset and easy to look at with a simple eye, it is safe to say that no green light"The reason is clear: the red color of the solar disk indicates a strong scattering of blue and green rays by the atmosphere, i.e., the entire upper rim of the disk. "On the contrary, - the astronomer continues, - if the Sun has changed little from its usual whitish-yellow color and sets very brightly(i.e., if the absorption of light by the atmosphere is small. - Ya. P.), then it is possible with a high probability wait for the green light. But here it is just important that the horizon be a sharp line, without any irregularities, nearby forest, buildings, etc. These conditions are best met at sea; that is why the green beam is so well known to sailors."

So, to see the "green beam", you need to observe the Sun at the time of sunset or sunrise with a very clear sky. In southern countries, the sky near the horizon is more transparent than ours, so the phenomenon of the "green beam" is observed there more often. But in our country it is not as rare as many people think, probably under the influence of Jules Verne's novel. The persistent search for the "green ray" is sooner or later rewarded with success. It happened to capture this beautiful phenomenon even with a telescope. Two Alsatian astronomers describe such an observation as follows:
"... In the last minute before sunset, when, therefore, a noticeable part of it is still visible, the disk, which has a wavy moving, but sharply defined border, is surrounded by a green rim. Until the Sun has completely set, this rim is not visible to the naked eye. It becomes visible only at the moment of the complete disappearance of the Sun behind the horizon.If you look through a telescope with a sufficiently strong magnification (about 100 times), you can trace all the phenomena in detail: the green border becomes noticeable at the latest 10 minutes before sunset; the upper part of the disk, while from the bottom there is a red border.The width of the border, at first very small (only a few seconds of arc), increases as the Sun sets, it sometimes reaches up to half a minute of the arc.Above the green rim, green protrusions are often observed, which, with a gradual the disappearance of the Sun, as it were, glide along its edge to the highest point; sometimes they break away from the rim and shine separately for several seconds, until they go out "Usually, the phenomenon lasts a second or two. But under exceptional circumstances, its duration is noticeably lengthened. A case was noted when the "green beam" was observed for more than 5 minutes! The sun was setting behind a distant mountain, and a fast-paced observer saw a green border of the solar disk, as if sliding along the mountainside.

Very instructive are the cases of observing the "green beam" at sunrise, when the upper edge of the luminary begins to appear from under the horizon. This refutes the often expressed conjecture that the "green beam" is an optical illusion that the eye succumbs to when weary of the bright brilliance of the Sun that has just set.

“Have you ever watched the Sun set below the horizon of the sea? Yes, without a doubt. Have you followed it to the point where the top edge of the disk touches the horizon and then disappears? Probably yes. But have you noticed the phenomenon that occurs at the moment when the luminous luminary throws its last ray, if at the same time the sky is free from clouds and completely transparent?

Perhaps not. Do not miss the opportunity to make such an observation: it is not a red beam that will strike your eye, but a green, marvelous green color, such that no artist can get on his palette and that nature itself does not reproduce either in various shades of vegetation or in color. the most transparent sea.

A similar note in an English newspaper brought the young heroine of Jules Verne's The Green Ray into an enthusiastic state and prompted her to undertake a series of journeys with the sole purpose of seeing the green beam with her own eyes.

The young Scot failed, as the novelist says, to observe this beautiful natural phenomenon. But it still exists. The green beam is not a legend, although there is a lot of legend associated with it. This is a phenomenon that every nature lover can admire if he searches for it with due patience.

Why does the green beam appear?

You will understand the cause of the phenomenon if you remember in what form objects appear to us when we look at them through a glass prism. Do this experiment: hold the prism near the eye horizontally with the wide side down and look through it at a piece of paper pinned to the wall. You will notice that the leaf, firstly, has risen much higher than its true position, and secondly, it has a violet-blue border at the top, and a yellow-red one at the bottom.

The rise depends on the refraction of light, the colored borders - on the dispersion of glass, i.e. the properties of glass to refract rays of different colors unequally. Violet and blue rays are refracted more strongly than others, so we see a violet-blue border at the top; red ones are refracted the weakest, and therefore the lower edge of our paper sheet has a red border.

For a better understanding of what follows, it is necessary to dwell on the origin of these colored borders. The prism decomposes the white light emanating from the paper into all the colors of the spectrum, giving many color images of the paper sheet, arranged, partly superimposed on one another, in the order of refraction.

From the simultaneous action of these superimposed. On top of each other of color images, the eyes get a sense of white color (the addition of spectral colors), but at the top and bottom there are rims of immiscible colors. The famous poet Goethe, who did this experiment and did not understand its meaning, imagined that he had thus exposed the falsity of Newton's doctrine of colors, and then wrote his own "Science of Flowers", which is almost entirely based on false ideas.

The reader, presumably, will not repeat the delusions of the great poet and will not expect that the prism will repaint all objects for him. The earth's atmosphere is for our eyes like a huge air prism, turned base down. Looking at the Sun at the horizon, we look at it through a gas prism.

The disk of the Sun receives a border of blue and green at the top, and red-yellow at the bottom. As long as the Sun is above the horizon, the light of the disk interrupts much less bright colored stripes with its brightness, and we do not notice them at all. But at the moments of sunrise and sunset, when almost its entire disk is hidden under the horizon, we can see the blue border of the upper edge. It is two-tone: above is a blue stripe, below - blue, from a mixture of blue and green rays.

When the air near the horizon is completely clear and transparent, we see a blue border - the “blue ray”. But more often the blue rays are scattered by the atmosphere and only one green border remains: the “green ray” phenomenon. Finally, in most cases, blue and green rays are also scattered by the cloudy atmosphere - then no border is noticed: the Sun sets in a crimson ball.

The Pulkovo astronomer G. A. Tikhov, who devoted a special study to the “green ray”, reports some signs of the visibility of this phenomenon. “If the Sun is red at sunset and easy to look at with the naked eye, then it is safe to say that there will be no green beam.”

The reason is clear: the red color of the solar disk indicates a strong scattering of blue and green rays by the atmosphere, i.e., the entire upper rim of the disk. “On the contrary,” the astronomer continues, “if the Sun has little changed its usual whitish-yellow color and sets very brightly (i.e., if the absorption of light by the atmosphere is small. - Ya. P.), then we can most likely expect a green beam.

But here it is just important that the horizon be a sharp line, without any irregularities, nearby forest, buildings, etc. These conditions are best met at sea; that is why the green beam is so well known to sailors.”

So, in order to see the “green beam”, you need to observe the Sun at the time of sunset or sunrise with a very clear sky. In southern countries, the sky near the horizon is more transparent than ours, so the “green beam” phenomenon is observed there more often.

But in our country it is not as rare as many people think, probably under the influence of Jules Verne's novel. The persistent search for the “green ray” is sooner or later rewarded with success. It happened to capture this beautiful phenomenon even with a telescope. Two Alsatian astronomers describe such an observation as follows:

“.. In the last minute before sunset, when, therefore, a noticeable part of it is still visible, the disk, which has a wavy moving, but sharply defined border, is surrounded by a green rim. Until the Sun has completely set, this rim is not visible to the naked eye. It becomes visible only at the moment of complete disappearance of the Sun behind the horizon.

If you look through a telescope with a sufficiently strong magnification (about 100 times), you can trace all the phenomena in detail: the green border becomes noticeable no later than 10 minutes before sunset; it limits the upper part of the disk, while a red border is observed from the lower one.

The width of the rim, initially very small (only a few seconds of arc), increases as the Sun sets; it sometimes reaches up to half a minute of the arc. Above the green rim, green protrusions are often observed, which, with the gradual disappearance of the Sun, seem to slide along its edge to the highest point; sometimes they break away from the rim and glow separately for several seconds until they go out” (Fig. 119).

Rice. 119. Long-term observation of the "green beam"; the observer saw a “green beam” behind the ridge for 5 minutes.

Above on the right is a “green beam” visible through a telescope. The disk of the Sun has irregular contours. In position 1, the brilliance of the solar disk blinds the eye and makes it difficult to see the green border with the naked eye. In position 2, when the disk of the Sun almost disappears, the "green beam" becomes available to the simple eye.

Usually the phenomenon lasts a second or two. But under exceptional circumstances, its duration is noticeably lengthened. A case was noted when the “green beam” was observed for more than 5 minutes! The sun was setting behind a distant mountain, and a fast-paced observer saw a green border of the solar disk, as if sliding along the mountainside (Fig. 119).

Very instructive are the cases of observing the “green beam” at sunrise, when the upper edge of the star begins to appear from under the horizon. This refutes the often expressed conjecture that the “green beam” is an optical illusion that the eye succumbs to when weary of the bright brilliance of the just setting Sun.

The sun is not the only luminary that sends out a “green beam”. It happened to see this phenomenon generated by the setting Venus. Fizmatgiz, 1958. Note. ed.].

Why does the green beam appear?

You will understand the cause of the phenomenon if you remember in what form objects appear to us when we look at them through a glass prism. Do this experiment: hold the prism near the eye horizontally with the wide side down and look through it at a piece of paper pinned to the wall. You will notice that the leaf, firstly, has risen much higher than its true position, and secondly, it has a violet-blue border at the top, and a yellow-red one at the bottom. Raising depends on the refraction of light, colored borders - on dispersion glass, i.e. glass properties unequally refract rays of different colors. Violet and blue rays are refracted more strongly than others, so we see a violet-blue border at the top; red ones are refracted the weakest, and therefore the lower edge of our paper sheet has a red border.

For a better understanding of what follows, it is necessary to dwell on the origin of these colored borders. The prism decomposes the white light emanating from the paper into all the colors of the spectrum, giving many color images of the paper sheet, arranged, partly superimposed on one another, in the order of refraction. From the simultaneous action of these color images superimposed on each other, the eye receives a sensation of white color (the addition of spectral colors), but rims of immiscible colors protrude above and below. The famous poet Goethe, who did this experiment and did not understand its meaning, imagined that he had thus exposed the falsity of Newton's doctrine of colors, and then wrote his own "Science of Flowers", which is almost entirely based on false ideas. The reader, presumably, will not repeat the delusions of the great poet and will not expect that the prism will repaint all objects for him. The earth's atmosphere is for our eyes like a huge air prism, turned base down. Looking at the Sun at the horizon, we look at it through a gas prism. The disk of the Sun receives a border of blue and green at the top, and red-yellow at the bottom. As long as the Sun is above the horizon, the light of the disk interrupts much less bright colored stripes with its brightness, and we do not notice them at all. But at the moments of sunrise and sunset, when almost its entire disk is hidden under the horizon, we can see the blue border of the upper edge. It is two-colored: above is a blue stripe, below - blue, from a mixture of blue and green rays. When the air near the horizon is completely clear and transparent, we see a blue border - a “blue ray”. But more often the blue rays are scattered by the atmosphere and only one green border remains: the "green beam" phenomenon. Finally, in most cases, blue and green rays are also scattered by the cloudy atmosphere - then no border is noticed: the Sun sets in a crimson ball.

Pulkovo astronomer G. A. Tikhov, who devoted a special study to the "green ray", reports some signs of the visibility of this phenomenon. “If the Sun is red at sunset and easy to look at with the naked eye, then it is safe to say that there will be no green beam.” The reason is clear: the red color of the solar disk indicates a strong scattering of blue and green rays by the atmosphere, i.e., the entire upper rim of the disk. “On the contrary,” the astronomer continues, “if the Sun has little changed its usual whitish-yellow color and sets very bright (that is, if the absorption of light by the atmosphere is small. - I.P.), then we can most likely expect a green beam. But here it is just important that the horizon be a sharp line, without any irregularities, nearby forest, buildings, etc. These conditions are best met at sea; that is why the green beam is so well known to sailors.”

So, to see the "green beam", you need to observe the Sun at the time of sunset or sunrise with a very clear sky. In southern countries, the sky near the horizon is more transparent than ours, so the phenomenon of the "green beam" is observed there more often. But in our country it is not as rare as many people think, probably under the influence of Jules Verne's novel. The persistent search for the "green ray" is sooner or later rewarded with success. It happened to capture this beautiful phenomenon even with a telescope. Two Alsatian astronomers describe such an observation as follows:

“... In the last minute before sunset, when, therefore, a noticeable part of it is still visible, the disk, which has a wavy moving, but sharply defined border, is surrounded by a green rim. Until the Sun has completely set, this rim is not visible to the naked eye. It becomes visible only at the moment of complete disappearance of the Sun behind the horizon. If you look through a telescope with a sufficiently strong magnification (about 100 times), you can trace all the phenomena in detail: the green border becomes noticeable no later than 10 minutes before sunset; it limits the upper part of the disk, while a red border is observed from the lower one. The width of the rim, initially very small (only a few seconds of arc), increases as the Sun sets; it sometimes reaches up to half a minute of the arc. Above the green rim, green protrusions are often observed, which, with the gradual disappearance of the Sun, seem to slide along its edge to the highest point; sometimes they break away from the rim and glow separately for several seconds until they go out” (Fig. 119).

Rice. 119. Long-term observation of the "green beam"; the observer saw the "green beam" behind the ridge for 5 minutes. Above on the right is the "green beam" visible through a telescope. The disk of the Sun has irregular contours. In position 1, the brilliance of the solar disk blinds the eye and makes it difficult to see the green border with the naked eye. In position 2, when the disk of the Sun almost disappears, the "green beam" becomes available to the simple eye.

Usually the phenomenon lasts a second or two. But under exceptional circumstances, its duration is noticeably lengthened. A case was noted when the "green beam" was observed for more than 5 minutes! The sun was setting behind a distant mountain, and a fast-paced observer saw a green border of the solar disk, as if sliding along the mountainside (Fig. 119).

Very instructive cases of observation of the "green beam" in sunrise Sun, when the upper edge of the luminary begins to appear from under the horizon. This refutes the often expressed conjecture that the "green beam" is an optical illusion that the eye succumbs to, tired of the bright brilliance of the just setting Sun.

The sun is not the only luminary that sends out a "green beam". It happened to see this phenomenon generated by the setting Venus. Fizmatgiz, 1958 Note. ed. ].