Seeing a rainbow, most of us smile and remember our childhood when this natural phenomenon was seen for the first time. There are many signs associated with, but a multi-colored arc that closes around the sun looks especially unusual and mystical. In science, this phenomenon is called a halo.

What is the phenomenon of a rainbow around the sun?

There are many types of halo, but all are caused by ice crystals in cirrus clouds. It is from their shape and location that the appearance of the halo depends. The light reflected and refracted by ice crystals is often decomposed into a spectrum, which makes the halo look like a rainbow. The halo that forms around the moon has no color, because at dusk it is simply impossible to distinguish it. This phenomenon is fixed in any weather, and in frost, the crystals are located very close to the surface of the earth and resemble shining precious stones, the so-called diamond dust.

The lower part of the halo can be seen against the background of the surrounding landscape if the main luminary is located low above the horizon. However, halos are not the same as crowns. The last natural phenomenon is associated with the formation of light hazy rings in the sky around the Sun or Moon.

What does a rainbow around the sun mean?

Those who are lucky enough to see this rare phenomenon should expect all the very best - well-being, prosperity, good luck and love. If before that there was not the easiest period in life, then it will definitely end and everything will work out in the best way.

If there are such signs associated with a circular rainbow around the sun:

There is a mass historical facts associated with the halo, when this natural phenomenon helped those who saw it in any business or vice versa, was interpreted as a bad sign. In particular, the Tale of Igor's Campaign says that the army was finally defeated when four Suns appeared in the sky. Ivan the Terrible regarded the natural phenomenon he saw as an omen of imminent death. There are a lot of signs about the rainbow. Such a belief is quite interesting: having taken a sip of water from the river from where the rainbow originates, she can guess the gender of her child. True, this applies only to those women who already have three daughters or three sons.

Halo is an interesting and unusual natural phenomenon. It appears as a luminous ring or halo around a bright light source. Most often this is the sun, but a similar halo can be seen around the moon (lunar halo), as well as other bright sources, such as street lamps. different types There are quite a lot of haloes, but at their core it has the same source - these are ice crystals. These crystals, most often, are located in cirrus clouds at a height of 5-10 km, but they are also found right near the ground. That's when you might see an "aura" around street lights or a halo around someone's head.

The type and shape of the halo is highly dependent on the shape and location of the crystals, and under certain conditions, even parhelion (false sun) can occur. Light passing through ice crystals is refracted and reflected at different angles. The value of this angle depends on the location of the crystals. If the halo is observed in good light conditions, then you can see the likeness of a rainbow. In fact, it's just refracted light decomposed into a spectrum. In low light, the “rainbow” cannot be seen due to the peculiarities of human vision, although in fact it is.

Disks around the sun can appear not only as a result of refraction on ice crystals, but also on water droplets that form a cloud or fog. Such discs are called crowns. They can be distinguished from halos by the fact that their radius is much smaller than that of a halo and does not exceed 5%.

I think I won’t surprise anyone if I say that in the past our ancestors endowed the halo around the sun with mystical properties and, most often, considered the appearance of such a miracle in the sky as a bad sign.

A few more photos of the sun halo:

The halo of the sun is not necessarily a single halo. There may be several.

The refraction of the sun's rays in the atmosphere gives rise to many optical illusions that can be observed from Earth with the naked eye. One of the most spectacular phenomena of this kind is the solar halo. This phenomenon has many varieties, each of which is beautiful in its own way. But for the occurrence of any kind of this optical illusion, a certain set of conditions is necessary.

So what is a solar halo and why does it appear? First, let's answer the first question. Basically, a halo is a rainbow around the sun. However, it differs from an ordinary rainbow in both appearance, as well as in terms of their characteristics.

A halo appears in the sky due to a combination of several factors. Most often it is observed in frosty weather in conditions of high humidity. In the air, there is a large number of ice crystals. Passing through them, sunlight is refracted in a special way, forming an arc around the Sun.

Do not confuse the halo with the "solar crowns". The latter are areas of hazy glow located around the Sun, Moon or other bright light sources - for example, street lamps and searchlights.

Despite some resemblance with a rainbow, the solar halo has a number of differences from it. The first of these is that a rainbow is usually observed while standing with your back to the luminary. A halo occurs only around the Sun, with the exception of a few extremely rare varieties.

In the rainbow, most often you can observe the entire spectrum of colors, from red to purple. The solar halo, on the other hand, is usually colored only in red and orange tones. The remaining colors of the spectrum mix with each other and therefore look white. However, it is very rare to observe a halo in which all colors of the spectrum are distinguished. This is a very impressive sight.

In a rainbow, the red spectrum is located on the outer side (farthest from the horizon). In the halo, it is as close as possible to the center, that is, to the Sun.

The main difference between a rainbow and a halo is that we see a rainbow as a result of the refraction of light in water droplets. These droplets always look and behave the same in the atmosphere, only their sizes can differ. Ice crystals, in which the light of the Sun is refracted during the observation of the halo, are quite another matter. They may have the most different shape and size. Yes, and crystals can move in completely different ways - calmly soar, fall down, rotate, etc. The result of this is the variety of types of solar halo.

Varieties of the solar halo

So, we learned what a solar halo is, and what are the reasons for its appearance. Now consider its main types.

The solar halo differs in its location in the sky relative to the Sun. Most often, you can observe halos located close to the star - the so-called 22-degree halos. Less common are halos located at an angle of 46 degrees or more with respect to the Sun, and the rarest are its varieties that occupy the entire sky.

According to their coloration, halos are divided into white (light, colorless), red-orange, and full spectrum. The most common 22-degree halos are usually only red, orange, and white. Halos can be located not only in the vertical, but also in the horizontal plane. They are called subhalos.

The attitude of people to the halo

In the past, this phenomenon sowed fear and panic among people. Due to the insufficient development of science, people did not know that an optical illusion was opening up to their eyes, and considered the halo to be an unkind sign, especially if it was accompanied by parhelia (light spots that looked like the Sun and were located next to it). Sometimes the appearance of a halo became the reason for making important political decisions. One of the most striking examples is the refusal of Emperor Charles V from the siege of Magdeburg in 1551. Seeing a halo with false suns over the city, he considered it a symbol of the heavenly protection of the besieged.

How to look at the solar halo

Halo is an unusual optical phenomenon that always attracts people's attention. But in order to enjoy its beauty without unpleasant consequences, one must not only know what a solar halo is, but also understand what danger it poses to the organs of vision. Sunlight refracted in ice crystals is too bright for our eyes. Therefore, it is best to observe the halo in sunglasses. It is wiser to use for this (as well as for being in the sun in any other conditions) high-quality glasses with a high level of UV protection. Looking at the halo, it is best to cover the sun with some object or, for example, with a palm. The same should be done when photographing this phenomenon. Otherwise, the image may not be clear enough.

Three suns rose in the sky over Chelyabinsk yesterday morning.

Local residents have witnessed the optical phenomenon of the halo, which can be observed in winter in frosty weather.

“In the Urals, it got colder to 23-25 ​​degrees below zero. Small hexagonal ice crystals formed in the air, which cannot be seen with the naked eye. The rays of the sun are refracted through them. As a result, an optical halo effect is created, ”explained the chief weather forecaster. Sverdlovsk region Galina Sheporenko.

“The type of halo can be varied - it can be iridescent or white stripes, spots, arcs and circles in the sky,” the forecaster said. According to her, it is extremely difficult to predict the onset of this phenomenon. It can happen several times over the winter.

Halo(from other Greek ἅλως - circle, disk; also aura, nimbus, halo) is an optical phenomenon, a luminous ring around a light source.

The halo usually appears around the Sun or Moon, sometimes around other powerful light sources such as street lights. There are many types of this natural phenomenon and they are caused mainly by ice crystals in cirrus clouds at an altitude of 5-10 km in the upper troposphere. The appearance depends on the shape and location of the crystals. The light reflected and refracted by ice crystals is often decomposed into a spectrum, which makes this phenomenon look like a rainbow. Parhelia and the zenith arc are the brightest and most full-color, while the tangents of the small and large halo are less bright. In a small 22-degree halo, only part of the colors of the spectrum (from red to yellow) is distinguishable, the rest looks white due to the repeated mixing of refracted rays. An interesting feature of the large 46-degree halo is that it is dim and of little color, while the upper tangential arc, which almost coincides with it at a low altitude of the Sun above the horizon, has pronounced iridescent colors. In the dim lunar halo, colors are not visible to the eye, which is associated with the peculiarities of twilight vision.

Sometimes in frosty weather, the halo is formed by crystals very close to earth's surface. In this case, the crystals resemble shining gems (the so-called diamond dust), and Bottom part The glow can be seen against the background of the surrounding landscape if the Sun is low enough above the horizon.

Light phenomena in clouds: halo, crowns

Halo- this is the refraction and reflection of light in the ice crystals of the clouds of the upper tier; are bright or iridescent circles around the sun or moon ( sample photo of the lunar halo), separated from the luminary by a dark gap. Halos are often observed in front of cyclones (in cirrostratus their clouds warm front) and therefore can serve as a sign of their approach.


Halo around the Sun in cirrostratus clouds

As a rule, halos appear as circles with a radius of 22 or 46°, the centers of which coincide with the center of the solar (or lunar) disk. The circles are faintly colored in iridescent colors (red inside).
Halos are the most sure sign worsening weather. So, at the end of March 1988, calm, sunny spring weather settled in Moscow and the Moscow region. But one evening, a halo was observed around the Moon; and the next day the weather deteriorated sharply.
From the book "Meteorology and Climatology" S.P.Khromov, M.A.Petrosyants: "In addition to the main halo forms, false suns are observed - slightly colored light spots at the same level with the Sun and at an angular distance from it also 22 or 46 °. K sometimes various tangent arcs are attached to the main circles.There are still uncolored vertical columns passing through the solar disk, i.e., as if continuing it up and down, as well as an uncolored horizontal circle at the same level with the Sun.
The colored halos are explained by the refraction of light in hexagonal prismatic crystals of ice clouds, the uncolored (colorless) forms are explained by the reflection of light from the faces of the crystals. The variety of halo shapes depends mainly on the types and movement of crystals, on the orientation of their axes in space, and also on the height of the Sun. The 22° halo is due to the refraction of light by the lateral faces of the crystals with a random orientation of their principal axes in all directions. If the main axes have a predominantly vertical direction, then on both sides of the solar disk (also at a distance of 22 °), instead of a bright circle, two bright spots appear - false suns.

The halo at 46° (and false suns at 46°) are due to the refraction of light between the side faces and bases of the prisms, i.e. with a refractive angle of 90°.
The horizontal circle is due to the reflection of light by the side faces of vertically arranged crystals, and the sun column is due to the reflection of light from crystals located predominantly horizontally.

In thin water clouds consisting of small homogeneous droplets (usually altocumulus) and luminaries covering the disk, due to diffraction, the phenomena of the crowns.

altocumulus

Crowns also appear in fog near artificial light sources. The main, and often the only part of the crown is a light circle of small radius, closely surrounding the disk of the luminary (or an artificial light source). The circle is mostly bluish in color and only reddish on the outer edge. It is also called a halo. It may be surrounded by one or more additional rings of the same, but of a lighter color, not close to the circle and to each other. Halo radius 1-5°. It is inversely proportional to the diameters of the droplets in the cloud, so it can be used to determine the size of the droplets in the clouds.
Crowns around artificial light sources of small size (compared to the disks of luminaries) have richer iridescent colors.

Folk omens halo related:

After the appearance of fast moving cirrus clouds, the sky is covered with a transparent (like a veil) layer of cirrostratus clouds. They are found in circles near the Sun or Moon (a sign of worsening weather).

cirrostratus clouds

A halo is visible around the Sun or Moon (a sign of worsening weather).
- In winter - white crowns of large diameter around the Sun or Moon, as well as pillars near the Sun, or the so-called false suns (a sign of frosty weather).
- The ring around the moon - to the wind (weather deterioration).

Let us quote the book by V.A. Mezentsev "Religious superstitions and their harm" (Moscow, 1959). Here is what is written there about the above phenomena: "Here, for example, what a complex and rare halo in its form was actually observed in the spring of 1928 in the city of Bely, Smolensk region. At about 8-9 o'clock in the morning on both sides of the Sun - to the right and left - two bright, iridescent, false suns are visible. They had short, slightly curved whitish tails. The real Sun was in the center of a luminous circle. In addition, several luminous arcs were visible in the sky. It was such arcs that in past centuries were taken for curves fiery swords hanging in the sky.
And on November 28, 1947, a complex halo around the Moon was observed in the city of Poltava. The moon was in the center of the light circle. New moons were also visible on the circle to the right and left, or, as they are often called, paracelens; the left paraselen was brighter and had a tail. The halo circle was not visible in its entirety. It was brightest in its upper part and on the left. At the top of the halo circle was a bright tangent arc.

How can such extraordinary images be obtained in the air? What are the reasons for this interesting natural phenomenon? Studying the appearance of a halo in the sky, scientists have long noticed that they occur when the Sun is covered with a white, brilliant haze - a thin veil of high cirrus clouds .

Spindrift clouds

Such clouds float at a height of 6-8 kilometers above the earth and consist of the smallest ice crystals, which are most often in the form of hexagonal columns or plates. Rising and falling in the air currents, ice crystals, like a mirror, reflect or, like a prism, refract the sun's rays falling on them. At the same time, reflected rays from some crystals can enter our eyes. Then we watch various forms halo. Here is one of these forms: a light horizontal circle appears in the sky, encircling the sky parallel to the horizon. Scientists conducted special experiments and found that such a circle arises due to reflection sunlight from the side faces of ice hexagonal crystals floating in the air in a vertical position. The rays of the Sun fall on such a crystal, are reflected from it, as from a mirror, and fall into our eyes. But our eyes cannot detect the curvature of light rays, so we see the reflected image of the Sun not where it actually is, but on a straight line coming from the eyes, and the image will be seen at the same height at the same height above the horizon as actual sun.

This phenomenon is similar to how we see the image of a light bulb in a mirror at the same time as the light bulb itself. There are a lot of such vertically floating mirror crystals in the air. They all reflect the sun's rays. The mirror images of the Sun, falling into our eyes from individual crystals, merge, and we see a solid bright circle parallel to the horizon. Or it happens like this: the Sun has just gone below the horizon, and in the dark evening sky suddenly appears light pillar . In this play of light, as shown by special experiments, ice plates participate, floating in the atmosphere in a horizontal position. The rays of the Sun, which has just gone beyond the horizon, fall on the oscillating lower edges of such plates, are reflected and fall into the eyes of the observer. When there are many such crystals in the air, the mirror images of the Sun that fall into our eyes from individual ice plates merge into one, and we see a stretched image of the solar disk distorted beyond recognition - a luminous column appears in the sky. Against the background of the evening dawn, it sometimes has a reddish color. With a phenomenon like this, each of us met more than once. Remember the solar or lunar "path" on the water. Here we see exactly the same distorted reflected Sun or Moon, only the role of a mirror is performed not by ice crystals, but by the surface of the water. Have you ever seen a bright rainbow circle surrounding the Sun? This is also one of the forms of the halo. It has been established that this halo is formed when there are many hexagonal ice crystals in the air, which refract the sun's rays like a glass prism. We do not see most of these refracted rays, they are scattered in the air. But from some crystals, directed rays also enter our eyes. Such crystals are located in the sky in a circle around the Sun. All of them seem to us illuminated, and in this place we see a light circle, slightly colored in iridescent tones. We do not always see one form or another of the halo completely in the sky. For example, in winter, during severe frosts, two light spots appear on both sides of the Sun. These are parts of the halo circle. In another case, only the upper part of such a circle is visible - above the Sun. In the past, it was often mistaken for a luminous crown. The same happens with a horizontal circle passing through the Sun. Most often, only that part of it that adjoins the Sun is visible; then we observe in the sky, as it were, two bright tails stretching to the right and left of the Sun. It is not difficult to understand how luminous crosses appear in the air. From the Sun, which is low at the horizon or has already gone beyond the horizon, a long luminous column stretches upward. This column intersects with the part of the halo circle visible above the Sun, and a large luminous cross appears in the sky. Two crosses may appear. This happens when the sky shows the vertical parts of the halo circle and parts of the horizontal circle adjacent to the Sun; intersecting, they give two crosses on either side of the Sun. In other cases, instead of crosses, only luminous spots are visible, which are close in size to the Sun.

They are called false suns. Usually this type of halo is observed when the Sun is not high above the horizon. Specially conducted experiments show that hexagonal crystals participate in the formation of false suns, which float in the air not randomly, but in such a way that their axes are predominantly vertical. In the northern regions, where a halo is generally observed much more often, suns can be seen dozens of times a year. Often they are so bright that they are not inferior to the Sun itself. Thus science explains the manifold, mysterious phenomena halo and exposes religious superstitions. By studying various phenomena associated with the passage of light in the atmosphere, our scientists not only give them a scientifically correct, materialistic explanation, but also use the acquired knowledge for the development of science. So, the observations of the crowns, which we talked about, helps to determine the size of ice crystals and water drops, from which various clouds are formed. Observations of crowns and halos also make it possible to predict the weather scientifically. So, if the crown that appears gradually decreases, precipitation can be expected. An increase in crowns, on the contrary, portends the onset of dry, clear weather.

Prepared by O. Malakhov. Photo by Meteoweb.ru