We present to you a selection of 20 of the most beautiful natural phenomena associated with the play of light. Truly natural phenomena are indescribable - you have to see it! =)

Let us conditionally divide all light metamorphoses into three subgroups. The first is Water and Ice, the second is Rays and Shadows, and the third is Light contrasts.

Water and Ice

“Near-horizontal Arc”

This phenomenon is also known as a “fire rainbow”. Created in the sky when light is refracted through ice crystals in cirrus clouds. This phenomenon is very rare, since both the ice crystals and the sun must be exactly in a horizontal line for such a spectacular refraction to occur. This particularly successful example was captured in the skies over Spokane in Washington, DC, in 2006.

A couple more examples of fire rainbows

When the sun shines on a climber or other object from above, a shadow is projected onto the fog, creating a curiously enlarged triangular shape. This effect is accompanied by a kind of halo around the object - colored circles of light that appear directly opposite the sun when sunlight is reflected by a cloud of identical water droplets. This natural phenomenon received its name due to the fact that it was most often observed on the low German peaks of Brocken, which are quite accessible to climbers, due to frequent fogs in this area

In a nutshell - it’s a rainbow upside down =) It’s like a huge multi-colored smiley face in the sky) This miracle is achieved due to the refraction of the sun’s rays through horizontal ice crystals in clouds of a certain shape. The phenomenon is concentrated at the zenith, parallel to the horizon, the color range is from blue at the zenith to red towards the horizon. This phenomenon is always in the form of an incomplete circular arc; bringing this situation full circle is the exceptionally rare Infantry Arc, which was first captured on film in 2007

Misty Arc

This strange halo was spotted from the Golden Gate Bridge in San Francisco - it looked like an all-white rainbow. Like a rainbow, this phenomenon is created due to the refraction of light through water droplets in the clouds, but, unlike a rainbow, due to the small size of the fog droplets, there seems to be a lack of color. Therefore, the rainbow turns out to be colorless - just white) Sailors often refer to them as “sea wolves” or “foggy arcs”

Rainbow halo

When light is scattered back (a mixture of reflection, refraction and diffraction) back to its source, the water droplets in the clouds, the shadow of an object between the cloud and the source can be divided into bands of color. Glory is also translated as unearthly beauty - a fairly accurate name for such a beautiful natural phenomenon) In some parts of China, this phenomenon is even called the Light of Buddha - it is often accompanied by the Brocken Ghost. In the photo, beautiful stripes of color effectively surround the shadow of the airplane opposite the cloud.

Halos are one of the most famous and common optical phenomena, and they appear under many guises. The most common phenomenon is the solar halo phenomenon, caused by the refraction of light by ice crystals in cirrus clouds at high altitude, and the specific shape and orientation of the crystals can create a change in the appearance of the halo. During very cold weather, halos formed by crystals near the ground reflect sunlight between them, sending it in several directions at once - this effect is known as “diamond dust.”

When the sun is at exactly the right angle behind the clouds, the water droplets in them refract the light, creating an intense trail. Coloration, as in a rainbow, is caused by different wavelengths of light - different wavelengths are refracted to different degrees, changing the angle of refraction and therefore the colors of light as we perceive them. In this photo, the iridescence of the cloud is accompanied by a sharply colored rainbow.

A few more photos of this phenomenon

The combination of a low Moon and dark skies often creates lunar arcs, essentially rainbows produced by the light of the moon. Appearing at the opposite end of the sky from the Moon, they usually appear completely white due to the faint coloring, but long exposure photography can capture the true colors, as in this photo taken in Yosemite National Park, California.

A few more photos of the lunar rainbow

This phenomenon appears as a white ring surrounding the sky, always at the same height above the horizon as the Sun. Usually it is possible to catch only fragments of the whole picture. Millions of vertically arranged ice crystals reflect the sun's rays across the sky to create this beautiful phenomenon.

So-called false Suns often appear on the sides of the resulting sphere, such as in this photo

Rainbows can take many forms: multiple arcs, intersecting arcs, red arcs, identical arcs, arcs with colored edges, dark stripes, “spokes” and many others, but what they have in common is that they are all divided into colors - red, orange, yellow , green, blue, indigo and violet. Do you remember from childhood the “memory” of the arrangement of colors in a rainbow - Every Hunter Wants to Know Where the Pheasant Sits? =) Rainbows appear when light is refracted through drops of water in the atmosphere, most often during rain, but haze or fog can also create similar effects, and are much rarer than one might imagine. At all times, many different cultures have attributed many meanings and explanations to rainbows, for example, the ancient Greeks believed that rainbows were the path to heaven, and the Irish believed that in the place where the rainbow ends, the leprechaun buried his pot of gold =)

More information and beautiful photos on the rainbow can be found

Rays and Shadows

A corona is a type of plasma atmosphere that surrounds an astronomical body. The most famous example of such a phenomenon is the corona around the Sun during a total eclipse. It extends thousands of kilometers in space and contains ionized iron heated to almost a million degrees Celsius. During an eclipse, its bright light surrounds the darkened sun and it seems as if a crown of light appears around the luminary

When dark areas or permeable obstacles, such as tree branches or clouds, filter the sun's rays, the rays create entire columns of light emanating from a single source in the sky. This phenomenon, often used in horror films, is usually observed at dawn or dusk and can even be witnessed under the ocean if the sun's rays pass through strips of broken ice. This beautiful photo was taken in Utah National Park

A few more examples

Fata Morgana

The interaction between cold air near ground level and warm air just above can act as a refractive lens and turn upside down the image of objects on the horizon, along which the actual image appears to oscillate. In this photo taken in Thuringia, Germany, the horizon in the distance appears to have disappeared altogether, although the blue portion of the road is simply a reflection of the sky above the horizon. The claim that mirages are completely non-existent images that appear only to people lost in the desert is incorrect, likely confused with the effects of extreme dehydration, which can cause hallucinations. Mirages are always based on real objects, although it is true that they may appear closer due to the mirage effect

The reflection of light by ice crystals with almost perfectly horizontal flat surfaces creates a strong beam. The light source can be the Sun, the Moon, or even artificial light. An interesting feature is that the pillar will have the color of that source. In this photo taken in Finland, the orange sunlight at sunset creates an equally orange gorgeous pillar

A couple more “solar pillars”)

Light contrasts

The collision of charged particles in the upper atmosphere often creates magnificent light patterns in the polar regions. Color depends on the elemental content of the particles - most auroras appear green or red due to oxygen, but nitrogen sometimes creates a deep blue or purple appearance. In the photo - the famous Aurora Borilis or Northern Lights, named after the Roman goddess of the dawn Aurora and the ancient Greek god of the north wind Boreas

This is what the Northern Lights look like from space

Condensation trail

The trails of steam that follow an airplane across the sky are some of the most stunning examples of human intervention in the atmosphere. They are created either by aircraft exhaust or air vortices from the wings and appear only in cold temperatures at high altitudes, condensing into ice droplets and water. In this photo, a bunch of contrails criss-cross the sky, creating a bizarre example of this unnatural phenomenon.

High-altitude winds bend the wakes of rockets, and their small exhaust particles turn sunlight into bright, iridescent colors that are sometimes carried by those same winds thousands of kilometers before they finally dissipate. The photo shows traces of a Minotaur missile launched from the US Air Force Base in Vandenberg, California.

The sky, like many other things around us, scatters polarized light that has a specific electromagnetic orientation. Polarization is always perpendicular to the light path itself, and if there is only one direction of polarization in the light, the light is said to be linearly polarized. This photo was taken with a polarized wide-angle filter lens to show how exciting the electromagnetic charge in the sky looks. Pay attention to what shade the sky has near the horizon, and what color it is at the very top.

Technically invisible to the naked eye, this phenomenon can be captured by leaving the camera with the lens open for at least an hour, or even overnight. The natural rotation of the Earth causes the stars in the sky to move across the horizon, creating remarkable trails in their wake. The only star in the evening sky that is always in one place is, of course, Polaris, since it is actually on the same axis with the Earth and its vibrations are noticeable only at the North Pole. The same would be true in the south, but there is no star bright enough to observe a similar effect

And here is a photo from the pole)

A faint triangular light seen in the evening sky and extending towards the heavens, the Zodiacal light is easily obscured by light atmospheric pollution or moonlight. This phenomenon is caused by the reflection of sunlight from dust particles in space, known as cosmic dust, hence its spectrum is absolutely identical to that of the Solar System. Solar radiation causes dust particles to slowly grow, creating a majestic constellation of lights gracefully scattered across the sky

REFRACTION OF LIGHT WHEN PASSING FROM WATER INTO AIR

A stick dipped into water, a spoon in a glass of tea, due to the refraction of light on the surface of the water, seems refracted to us.

Place a coin at the bottom of an opaque container so that it is not visible. Now pour water into the vessel. The coin will be visible. The explanation for this phenomenon is clear from the video.

Look at the bottom of the reservoir and try to estimate its depth. Most often it is not possible to do this correctly.

Let us trace in more detail how and to what extent the depth of the reservoir seems reduced to us if we look at it from above.

Let H (Fig. 17) be the true depth of the reservoir, at the bottom of which lies a small object, for example a pebble. The light reflected by it diverges in all directions. A certain beam of rays falls on the surface of the water at point O from below at an angle a 1, is refracted on the surface and enters the eye. In accordance with the law of refraction, we can write:

but since n 2 = 1, then n 1 sin a 1 = sin ϒ 1.

The refracted ray enters the eye at point B. Note that not one ray enters the eye, but a bundle of rays, the cross section of which is limited by the pupil of the eye.

In Figure 17, the beam is shown with thin lines. However, this beam is narrow and we can neglect its cross section, taking it as line AOB.

The eye projects A to point A 1, and the depth of the reservoir seems to us equal to h.

The figure shows that the apparent depth of the reservoir h depends on the true value of H and on the viewing angle ϒ 1.

Let us express this dependence mathematically.

From triangles AOC and A 1 OC we have:

Excluding OS from these equations, we get:

Considering that a = ϒ 1 and sin ϒ 1 = n 1 sin a 1 = n sin a, we obtain:

In this formula, the dependence of the apparent depth of the reservoir h on the true depth H and the observation angle does not appear explicitly. To present this dependence more clearly, let us express it graphically.

On the graph (Fig. 18), the values ​​of observation angles in degrees are plotted along the abscissa axis, and the corresponding apparent depths h in fractions of the actual depth H are plotted along the ordinate axis. The resulting curve shows that at small observation angles the apparent depth

is about ¾ of the actual value and decreases as the viewing angle increases. When the viewing angle is a = 47°, total internal reflection occurs and the beam cannot escape from the water.

MIRAGES

In an inhomogeneous medium, light travels non-linearly. If we imagine a medium in which the refractive index changes from bottom to top, and mentally divide it into thin horizontal layers,

then, considering the conditions for the refraction of light when passing from layer to layer, we note that in such a medium the light ray should gradually change its direction (Fig. 19, 20).

The light beam undergoes such bending in the atmosphere, in which for one reason or another, mainly due to its uneven heating, the refractive index of air changes with height (Fig. 21).

The air is usually heated by the soil, which absorbs energy from the sun's rays. Therefore, the air temperature decreases with height. It is also known that air density decreases with height. It has been established that with increasing altitude the refractive index decreases, so rays passing through the atmosphere are bent, bending towards the Earth (Fig. 21). This phenomenon is called normal atmospheric refraction. Due to refraction, the celestial bodies appear to us somewhat “raised” (above their true height) above the horizon.

It is calculated that atmospheric refraction “raises” objects located at a height of 30° by 1"40", at a height of 15° by 3"ZO", at a height of 5° by 9"45". For bodies located on the horizon, this value reaches 35". These figures deviate in one direction or another depending on the pressure and temperature of the atmosphere. However, for one reason or another, in the upper layers of the atmosphere there may be masses of air with a temperature higher than lower layers. They can be brought by winds from hot countries, for example, from a hot desert area. If at this time there is cold, dense air of an anticyclone in the lower layers, then the phenomenon of refraction can significantly intensify and rays of light emerging from earthly objects upward at a certain angle to the horizon, can return back to the ground (Fig. 22).

However, it may happen that at the surface of the Earth, due to its strong heating, the air becomes so hot that the refractive index of light near the soil becomes less than at a certain height above the soil. If the weather is calm, this condition can persist for quite a long time. Then the rays from objects falling at some rather large angle to the Earth’s surface can be bent so much that, having described an arc near the Earth’s surface, they go from bottom to top (Fig. 23a). The case shown in Figure 236 is also possible.

The conditions described above in the atmosphere explain the occurrence of interesting phenomena - atmospheric mirages. These phenomena are usually divided into three classes. The first class includes the most common and simple in origin, the so-called lake (or lower) mirages, which cause so much hope and disappointment among desert travelers.

The French mathematician Gaspard Monge, who participated in the Egyptian campaign of 1798, describes his impressions of this class of mirages:

“When the surface of the Earth is strongly heated by the Sun and is just beginning to cool before the onset of twilight, the familiar terrain no longer extends to the horizon as during the day, but turns, as it seems, at about one league into a continuous flood.

The villages further away look like islands in a vast lake. Under each village is its overturned reflection, only it is not sharp, small details are not visible, like a reflection in water shaken by the wind. If you begin to approach a village that seems to be surrounded by a flood, the shore of the imaginary water moves away, the water arm that separated us from the village gradually narrows until it disappears completely, and the lake... now begins behind this village, reflecting in itself the villages located further" (Fig. 24).

The explanation for this phenomenon is simple. The lower layers of air, heated from the soil, have not yet had time to rise upward; their refractive index of light is less than the upper ones. Therefore, rays of light emanating from objects (for example, from point B on a palm tree, Fig. 23a), bending in the air, enter the eye from below. The eye projects a beam to point B 1. The same happens with rays coming from other points of the object. The object appears to the observer to be overturned.

Where does the water come from? Water is a reflection of the sky.

To see a mirage, there is no need to go to Africa. It can be observed on a hot, quiet summer day above the heated surface of an asphalt highway.

Mirages of the second class are called superior or distant vision mirages. The “unheard-of miracle” described by N.V. Gogol is most similar to them. Here are descriptions of several such mirages.

From the Cote d'Azur of France, on an early clear morning, from the waters of the Mediterranean Sea, from beyond the horizon, a dark chain of mountains rises, in which residents recognize Corsica. The distance to Corsica is more than 200 km, so line of sight is out of the question.

On the English coast, near Hastings, you can see the French coast. As the naturalist Nie Digue reports, “near Reggio in Calabria, opposite the Sicilian coast and the city of Messina, entire unfamiliar areas with grazing herds, cypress groves and castles are sometimes visible in the air. After staying in the air for a short time, the mirages disappear.”

Distant vision mirages appear if the upper layers of the atmosphere turn out to be especially rarefied for some reason, for example when heated air gets there. Then the rays emanating from earthly objects are bent more strongly and reach the earth's surface, going at a large angle to the horizon. The observer's eye projects them in the direction in which they enter it.

Apparently, the Sahara Desert is to blame for the fact that a large number of distant vision mirages are observed on the Mediterranean coast. Hot air masses rise above it, then are carried north and create favorable conditions for the occurrence of mirages.

Superior mirages are also observed in northern countries when warm southern winds blow. The upper layers of the atmosphere are heated, and the lower layers are cooled due to the presence of large masses of melting ice and snow.

Sometimes forward and backward images of objects are observed simultaneously. Figures 25-27 show exactly such phenomena observed in Arctic latitudes. Apparently, above the Earth there are alternating denser and more rarefied layers of air, bending the rays of light approximately as shown in Figure 26.

Mirages of the third class - ultra-long-range vision - are difficult to explain. Here is a description of several of them.

“Based on the testimony of several trustworthy persons,” writes K. Flamarion in the book “Atmosphere,” “I can report on a mirage that was seen in the city of Verviers (Belgium) in June 1815. One morning, the residents of the city saw an army in the sky, and it was so clear that they could distinguish the artillerymen’s costumes, a cannon with a broken wheel that was about to fall off... It was the morning of the Battle of Waterloo!” The distance between Waterloo and Verviers in a straight line is 105 km.

There are cases when mirages were observed at a distance of 800, 1000 or more kilometers.

Let us give another striking case. On the night of March 27, 1898, in the middle of the Pacific Ocean, the crew of the Bremen ship Matador was frightened by a vision. Around midnight, the crew spotted a ship about two miles (3.2 km) away that was battling a strong storm.

This was all the more surprising given that there was calm all around. The ship crossed the course of the Matador, and there were moments when it seemed that a collision between the ships was inevitable... The crew of the Matador saw how, during one strong wave impact on an unknown ship, the light in the captain's cabin went out, which was visible all the time in two portholes . After some time, the ship disappeared, taking with it the wind and waves.

The matter was clarified later. It turned out that all this happened with another ship, which at the time of the “vision” was located 1,700 km from the Matador.

What paths does light take in the atmosphere so that clear images of objects are preserved at such great distances? There is no exact answer to this question yet. Suggestions were made about the formation of giant air lenses in the atmosphere, the delay of a secondary mirage, that is, a mirage from a mirage. It is possible that the ionosphere * plays a role here, reflecting not only radio waves, but also light waves.

Apparently, the described phenomena have the same origin as other mirages observed on the seas, called the “Flying Dutchman” or “Fata Morgana,” when sailors see ghostly ships that then disappear and strike fear into superstitious people.

RAINBOW

Rainbow is a beautiful celestial phenomenon that has always attracted human attention. In earlier times, when people still knew very little about the world around them, the rainbow was considered a “heavenly sign.” So, the ancient Greeks thought that the rainbow was the smile of the goddess Iris.

A rainbow is observed in the direction opposite to the Sun, against the background of rain clouds or rain. A multi-colored arc is usually located at a distance of 1-2 km from the observer, sometimes it can be observed at a distance of 2-3 m against the background of water drops formed by fountains or water sprays.

The center of the rainbow is located on the continuation of the straight line connecting the Sun and the observer's eye - on the antisolar line. The angle between the direction towards the main rainbow and the anti-solar line is 41-42° (Fig. 28).

At the moment of sunrise, the antisolar point (point M) is on the horizon line and the rainbow has the appearance of a semicircle. As the Sun rises, the antisolar point moves below the horizon and the size of the rainbow decreases. It represents only part of a circle. For an observer located high up, for example on. on an airplane, the rainbow is seen as a complete circle with the observer's shadow in the center.

A secondary rainbow is often observed, concentric with the first, with an angular radius of about 52° and the colors are reversed.

When the Sun's altitude is 41°, the main rainbow ceases to be visible and only part of the side rainbow protrudes above the horizon, and when the Sun's altitude is more than 52°, the side rainbow is not visible either. Therefore, in mid- and equatorial latitudes this natural phenomenon is never observed during the midday hours.

The rainbow, like the spectrum, has seven primary colors that smoothly transform into one another. The type of arc, the brightness of the colors, and the width of the stripes depend on the size of the water droplets and their number. Large drops create a narrower rainbow, with sharply prominent colors; small drops create a vague, faded and even white arc. That is why a bright narrow rainbow is visible in the summer after a thunderstorm, during which large drops fall.

The theory of the rainbow was first given in 1637 by R. Descartes. He explained rainbows as a phenomenon related to the reflection and refraction of light in raindrops.

The formation of colors and their sequence were explained later, after unraveling the complex nature of white light and its dispersion in the medium. The diffraction theory of rainbows was developed by Ehry and Pertner.

Let's consider the simplest case: let a beam of parallel solar rays fall on a droplet shaped like a ball (Fig. 29). A ray incident on the surface of a drop at point A is refracted inside it according to the law of refraction: n 1 sin a = n 2 sin β, where n 1 = 1, n 2 ≈ 1.33 are the refractive indices of air and water, respectively, a is the angle incidence, β is the angle of refraction of light.

Inside the drop, the beam travels along straight line AB. At point B, the beam is partially refracted and partially reflected. Note that the smaller the angle of incidence at point B, and therefore at point A, the lower the intensity of the reflected beam and the greater the intensity of the refracted beam.

Beam AB, after reflection at point B, passes at an angle β 1 " = β 1 and reaches point C, where partial reflection and partial refraction of light also occur. The refracted ray leaves the drop at an angle y2, and the reflected ray can travel further to point D and etc. Thus, a ray of light in a drop undergoes repeated reflection and refraction. With each reflection, some of the light rays come out and their intensity inside the drop decreases. The most intense of the rays emerging into the air is the ray that exits the drop at point B. However, it is difficult to observe it, since it is lost against the background of bright direct sunlight.The rays refracted at point C create a primary rainbow against the background of a dark cloud, and the rays refracted at point D

give a secondary rainbow, which, as follows from the above, is less intense than the primary one.

For the case K=1 we get Θ = 2 (59°37" - 40°26") + 1 = 137° 30".

Therefore, the viewing angle of a first-order rainbow is:

φ 1 =180° - 137°30" = 42°30"

For the ray DE" giving a second-order rainbow, i.e. in the case K = 2, we have:

Θ = 2 (59°37" - 40°26") + 2 = 236°38".

Second-order viewing angle of a rainbow φ 2 = 180° - 234°38" = - 56°38".

It follows from this (this can also be seen from the figure) that in the case under consideration, a second-order rainbow is not visible from the ground. In order for it to be visible, light must enter the drop from below (Fig. 30, b).

When considering the formation of a rainbow, one more phenomenon must be taken into account - the unequal refraction of light waves of different lengths, that is, light rays of different colors. This phenomenon is called dispersion. Due to dispersion, the angles of refraction ϒ and the angles of deflection of rays Θ in a drop are different for rays of different colors. The course of three rays - red, green and violet - is shown schematically in Figure 30, a for a first-order arc and in Figure 30, b for a second-order arc.

From the pictures it is clear that the sequence of colors in these arcs is opposite.

Most often we see one rainbow. There are often cases when two rainbow stripes appear simultaneously in the sky, located one above the other; They observe, however, quite rarely, and an even larger number of rainbow celestial arcs - three, four and even five at the same time. This interesting phenomenon was observed by Leningraders on September 24, 1948, when in the afternoon four rainbows appeared among the clouds over the Neva. It turns out that rainbows can occur not only from direct sunlight; It often appears in the reflected rays of the Sun. This can be seen on the shores of sea bays, large rivers and lakes. Three or four such rainbows - ordinary and reflected - sometimes create a beautiful picture. Since the rays of the Sun reflected from the water surface go from bottom to top, the rainbow formed in these rays can sometimes look completely unusual.

You should not think that rainbows can only be seen during the day. It also happens at night, although it is always weak. You can see such a rainbow after a night rain, when the Moon appears from behind the clouds.

Some semblance of a rainbow can be obtained in the following experiment. Take a flask of water, illuminate it with sunlight or a lamp through a hole in a white board. Then a rainbow will become clearly visible on the board (Fig. 31, a), and the divergence angle of the rays compared to the initial direction will be about 41-42° (Fig. 31,6). Under natural conditions, there is no screen; the image appears on the retina of the eye, and the eye projects this image onto the clouds.

If a rainbow appears in the evening before sunset, then a red rainbow is observed. In the last five or ten minutes before sunset, all the colors of the rainbow except red disappear, and it becomes very bright and visible even ten minutes after sunset.

A rainbow on the dew is a beautiful sight.

It can be observed at sunrise on the grass covered with dew. This rainbow is shaped like a hyperbola.

HALMOS

Looking at a rainbow in a meadow, you will involuntarily notice an amazing uncolored halo of light - a halo surrounding the shadow of your head. This is not an optical illusion or a contrast phenomenon. When the shadow falls on the road, the halo disappears. What is the explanation for this interesting phenomenon? Dew drops certainly play an important role here, for when the dew disappears the phenomenon disappears.

To find out the cause of the phenomenon, perform the following experiment. Take a spherical flask filled with water and place it in sunlight. Let her represent a drop. Place a piece of paper behind the flask close to it, which will act as grass. Look at the bulb at a low angle relative to the direction of the incident rays. You will see it brightly illuminated by the rays reflected from the paper. These rays go almost exactly towards the rays of the Sun falling on the bulb. Take your eyes a little to the side, and the bright illumination of the bulb is no longer visible.

Here we are dealing not with a scattered, but with a directed beam of light emanating from a bright spot on the paper. The bulb acts as a lens, directing the light towards us.

A beam of parallel solar rays, after refraction in a bulb, gives on paper a more or less focused image of the Sun in the form of a bright spot. In turn, quite a lot of the light emitted by the spot is captured by the bulb and, after refraction in it, is directed back towards the Sun, including into our eyes, since we stand with our backs to the Sun. The optical disadvantages of our lens - the bulb - provide some scattered light flux, but still the main flux of light emanating from a bright spot on the paper is directed towards the Sun. But why is the light reflected from the blades of grass not green?

It does have a slight greenish tint, but it is essentially white, just like light reflected directionally from smooth painted surfaces, such as the reflections from a green or yellow chalkboard or stained glass.

But dew droplets are not always spherical. They may be distorted. Then some of them direct the light to the side, but it goes past the eyes. Other droplets, such as those shown in Figure 33, have such a shape that the light falling on them, after one or two reflections, is directed back towards the Sun and enters the eyes of an observer standing with his back to it.

Finally, one more ingenious explanation of this phenomenon should be noted: only those grass leaves on which the direct light of the Sun falls, i.e. those that are not obscured by other leaves from the Sun, reflect light directionally. If we consider that the leaves of most plants always turn their plane towards the Sun, then it is obvious that there will be quite a lot of such reflective leaves (Fig. 33, e). Therefore, halos can also be observed in the absence of dew, on the surface of a smoothly mown meadow or compressed field.

Whenever a rainbow appears, it is always formed by the play of light on drops of water. Usually these are raindrops, occasionally small drops of fog. On the smallest drops, such as those that make up clouds, rainbows are not visible.

Rainbows occur because the sun light undergoes refraction in water droplets, suspended in the air. These droplets bend light of different colors differently, causing white light to split into a spectrum.

On a bright moonlit night you can see rainbow from the moon. Since human vision is designed in such a way that in low light the eye does not perceive colors well, a lunar rainbow appears whitish; The brighter the light, the more “colorful” the rainbow.

According to an old English belief, a pot of gold can be found at the foot of every rainbow. Even now there are people who imagine that they can really get to the foot of the rainbow and that a special flickering light is visible there.

It is quite obvious that the rainbow is not in any specific place, similar to the real thing; it is nothing more than light coming from a certain direction.

Most often observed primary rainbow, in which light undergoes one internal reflection. The path of the rays is shown in the figure below. In the primary rainbow, the red color is outside the arc, its angular radius is 40-42°.

Sometimes you can see another, less bright rainbow around the first one. This secondary rainbow, in which light is reflected twice in a drop. In a secondary rainbow, the order of colors is “inverted” - purple is on the outside and red is on the inside. The angular radius of the secondary rainbow is 50-53°.

The order of the colors in the second rainbow is the reverse of the order in the first; they face each other with red stripes.

Rainbow formation diagram

1. spherical drop,
2. internal reflection,
3. primary rainbow,
4. refraction,
5. secondary Rainbow,
6. incoming ray of light,
7. the course of rays during the formation of the primary rainbow,
8. the course of rays during the formation of a secondary rainbow,
9. observer,
10. rainbow formation area,
11. rainbow formation area.
12. rainbow formation area.

The center of the circle that a rainbow describes always lies on a straight line passing through the Sun (Moon) and the observer’s eye, that is, it is impossible to see the sun and a rainbow at the same time without using mirrors.

Strictly speaking, a rainbow is a complete circle. We can't follow it beyond the horizon just because we can't see the raindrops falling below us.

From an airplane or higher ground, the full circle can be seen.

"Seven Colors of the Rainbow" exist only in the imagination. This is a rhetorical turn of phrase that lasts so long because we rarely see things as they really are. In fact, the colors of the rainbow gradually transform into one another, and only the eye involuntarily combines them into groups.

The tradition of highlighting in the rainbow 7 colors went from Isaac Newton, for which the number 7 had a special symbolic meaning (for either Pythagorean or theological reasons). The tradition of identifying 7 colors in the rainbow is not universal; for example, Bulgarians have 6 colors in the rainbow.

To remember the sequence of colors in the rainbow, there are mnemonic phrases, the first letters of each word in which correspond to the first letters in the names of the colors (Red, Orange, Yellow, Green, Light Blue, Blue, Purple

"TO every O hunter and wants h nah, G de With goes f adhan". "How Jacques the Bell-ringer once broke a lantern with his head".

The man is a great master at building castles in the air on the sand. However, practice shows that he is far from Mother Nature. The craftswoman from God is capable of such deception of our feelings that it takes our breath away! But no matter how magical the optical phenomena, examples of which we will consider, may look, they are not a phantasmagoria, but the result of the flow of physical processes. In the heterogeneous atmosphere of the Earth, rays of light are bent, causing a host of illusions. But is it possible to imagine a world without dreams and visions? He would be so gray...

Light and color

Speaking about light and the forms of which have been observed by more than one generation of people, we emphasize that colors appear in the atmosphere due to the fact that white light, during interaction with materials in the atmosphere, is divided into its component parts (spectrum). This interaction occurs through one of three main forms: reflection, refraction (refraction) and diffraction.

If we're talking about the spectrum, think about how to teach your child to remember the collection of color stripes that are produced when a light beam passes through a refractive medium. A simple phrase will help: “Every (red) hunter (orange) wants (yellow) to know (green) where the (blue) pheasant (purple) sits.”

There is the emergence of secondary waves propagating from the boundary of two media back to the first medium. Refraction is the refraction of rays at the boundary of two media. Diffraction is the bending of solid particles, liquid droplets, and other materials present in the atmosphere by light fluxes. All this is the reason for the “optical illusion of vision” that flourishes in the Universe. There are many examples: from the blue color of the sky, mirages and rainbows to false suns and solar pillars.

Internal reflection

Optical phenomena in physics are an important section worthy of in-depth study. So let's continue. Reflection occurs when they fall on a smooth surface and return at an angle equal to the incoming one. This phenomenon explains the origin of color: some parts of white are more easily absorbed and reflected than others. For example, an object that appears to be green appears green because it absorbs all wavelengths of white light except green, which is what is reflected.

One form, internal reflection, is often present in the explanation of optical phenomena. Light enters a transparent physical body (material), for example a drop of water, through the outer surface and shines from the inner one. Then, a second time - from the material. The color of the rainbow can be partly explained in terms of internal reflection.

Rainbow-arc

A rainbow is an optical phenomenon that occurs when sunlight and rain combine in a specific way. Rays of sunlight are separated into the colors we see in the rainbow when they enter raindrops. This happens when the beam falls on the “rains” directed towards the Earth at a certain angle, the colors are separated (white light is decomposed into a spectrum), and we see a bright, festive rainbow, reminiscent of a giant semicircular bridge.

The variegation of curved stripes seems to hang directly overhead. The emitting source will always be behind us: it is impossible to see the clear sun and the beautiful rainbow at once (unless you use a mirror for this purpose). The phenomenon is not alien to the Moon. When the moonlit night is bright, you can see a rainbow “fan” in the vicinity of Selena.

When almost nothing is visible around, the most light-sensitive photoreceptors of the human eye, the “rods,” work. They are sensitive to the emerald green part of the spectrum and “do not see” other colors. As a result, the rainbow appears whitish. When the lighting intensifies, the “cones” are connected, thanks to these nerve endings the arc looks more colorful.

Mirage

From Earth we see only part of the circumference of the primary rainbow. In this case, the light undergoes one reflection. You can see a round rainbow in the mountains. Did you know that there are two or even three “beauties”? The rainbow that rises above the rainbow is less bright and “inverted” (after all, it is a reflection of the first). The third happens where the air is crystal clear and transparent (for example, in the mountains). This is about the usual spectacle.

A mirage is an optical phenomenon that cannot be called ordinary. In Russia it is relatively rare. Every time we pronounce the magic word, we remember the legend of the ghost ship "The Flying Dutchman". According to legends, for the captain’s crimes, he will sail the oceans until the second coming.

And here is another “Dutch”. The cruiser Repulse, which sank in December 1941 off the coast of Ceylon, became volatile. He was seen “very close” by the crew of the British ship Vendor, who was in the Maldives area. In fact, the ships were separated by 900 kilometers!

Fata Morgana

“The Flying Dutchman” and others are optical phenomena, examples from the cohort of stunning “Fata Morgana” mirages (named after the heroine of the British epic). An unusual optical phenomenon is a combination of several forms at once. A complex, rapidly changing image is formed in the sky. Looking at the views of what is far beyond the horizon, it seems that you can go crazy, they are so “tangible”.

Miracles caused by atmospheric conditions can baffle anyone. Especially such as the appearance of a “layer of water” in the desert or on a hot road, caused by the refraction of rays. Not only children, but also adults cannot get rid of the feeling that animals, wells, trees, buildings are real. But, alas!

Light passes through layers of unevenly heated air, creating a kind of 3D image. Mirages can be inferior (a distant flat surface takes on the appearance of open water), lateral (they appear next to a very heated vertical surface), or chrono (they reproduce events of the past).

Northern lights

When thinking about what optical phenomena there are, it is impossible not to talk about the northern (polar) lights. It has two main forms: beautiful sparkling ribbons and cloud-like spots. Intense radiance, as a rule, is “ribbon-like.” It happens that colored luminous stripes cease to exist without breaking into components.

In the darkness of the sky, the curtain, as a rule, stretches in the direction from east to west. The “trail” can reach several thousand kilometers in width and several hundred in height. This is not a dense, but a thin “screen” through which the stars sparkle. A very beautiful sight.

The lower edge of the “scene” is clear, has a reddish or pink tint, the upper one seems to dissolve in the darkness, thanks to which the inexpressible depth of space is clearly felt. Let's discuss four types of auroras.

Homogeneous structure

A calm, simple form of radiance, bright from below and dissolving at the top, is called a uniform arc; active, mobile, with small folds and streams - a radiant arc. Shining folds overlapping each other (large to small) are called “radiant stripe”.

And the fourth type is when the area of ​​folds and loops becomes very large. After the end of activity, the tape acquires a homogeneous structure. There is an opinion that homogeneity is the main property of “His Excellency.” Folds appear only during periods of increased atmospheric activity.

There are other optical phenomena. We will not hesitate to list examples below. A squall is a glow that gives the entire polar cap a whitish-green glow. It is observed at the south and north poles of the Earth, in Iceland, Norway, etc. The phenomenon occurs as a result of the glow of the magnetized upper layers of the atmosphere when interacting with charged particles of the solar wind (this is the name given to the outflow of plasma from helium and hydrogen into space).

The following can be said about this: they are frequent on frosty days and are very effective.

Saint Elmo in crowns of green rays and halo

There are other optical phenomena. For example, a halo, the appearance of which is associated with ice crystals formed in the atmosphere. It is similar to a rainbow by dispersion (the decomposition of light into components), only not in a drop, but in the solid structure of ice.

Rainbows are similar to each other, because the drops are the same, they can only fall. The halo has a hundred types, since the crystals are different and very “nimble”: they either soar, or spin, or rush towards the Earth.

Dreaming of being “deceived” once again, you can admire the false sun (parhelion) or the Last Ones “sitting” on the sharp tops of tall buildings. Mysticism has nothing to do with it. This is an electrical discharge in the atmosphere. It often occurs during a thunderstorm or sandstorm (when particles become electrified).

Photographers love to catch the “green ray” (the flash above the sun and the refraction of rays at the horizon). It is best captured in open spaces, in cloudless weather. But the crowns (diffraction of light) are clearly visible when the area is shrouded in fog (rainbow circles around the headlights of your car - these are the crowns) and the sky is covered with a veil of clouds. In the fog of small droplets, the circles are especially beautiful. When the fog thickens, they blur. Therefore, a decrease in the number of rainbow rings is regarded as a signal of worsening weather. What a huge world this is - optical phenomena! The examples we have discussed are just the tip of the iceberg. Knowing about these phenomena, we can scientifically explain any atmospheric illusion.