Why do stars twinkle in the night sky? Why do stars twinkle? How the glow of a star appears and disappears.

Quite often, the stars in the sky flicker noticeably - they flash, tremble, and quickly change brightness. Although the twinkling of stars interferes with high-quality astronomical observations, this phenomenon makes the night sky seem alive and close.

The twinkling of stars is especially noticeable on windy and frosty nights, and in the summer, strong twinkling indicates the approach of a strong cyclone. In winter, the stars often shimmer different colors, similar precious stones in the light. This applies primarily to stars located low above the horizon. Thus, the brightest star of the night sky, Sirius, twinkles and shimmers in different colors almost always, attracting increased attention.

Even the most beautiful photos the night sky cannot convey the twinkling of stars. Photo: Ruslan Merzlyakov

What is the reason for such phenomena?

Twinkling and shimmering of stars in different colors- these are not properties inherent in the stars themselves, but phenomena generated by the earth's atmosphere. The air envelope of our planet is restless: air masses are in constant movement- rise and fall, move in different sides. In addition, they have different temperatures and density depending on the height above the Earth’s surface, atmospheric currents and many other factors. As a result, air lenses and prisms are formed in the atmosphere, refracting and deflecting the light of distant celestial bodies passing through them.

But it's just air, you might object. How can it play the role of a prism or lens?

Light doesn't care what is in front of it - solid material, air or liquid. Light inevitably refracts at the boundary of two media having different densities. How more difference in density, the more noticeably the light is refracted. Classic examples are a prism or a glass of water. A spoon standing in a glass appears to be broken due to the refraction of light at the boundary of air and water.

Because air masses in the atmosphere have different densities depending on the height, currents, Hadley cells formed here and there and other factors, then they themselves are capable of playing the role of such prisms and lenses, albeit rather weak ones. When the light of a star passes through a lens, it comes to us amplified; when it is deflected, it comes attenuated. This rapid fluctuation of light is what we call flickering.

Why do stars twinkle and shimmer in different colors? Source: Natskies Observatory

Regarding stars changing colors, then the reason here is air circulation in the atmosphere. Using an ordinary prism as an example, it can be seen that light different lengths waves are bent differently. The same thing happens to starlight when it passes through air prisms. But first one color reaches us, then another, then a third. If you photograph such a star trembling and flickering in different colors with very short exposures, then in the photographs we will see literally the entire palette of colors!

Stars twinkle much more at the horizon than at the zenith because their light passes through more air. Figure: Bob King/Big Universe

We just have to explain why stars located low above the horizon twinkle and shimmer in different colors much more strongly than stars near the zenith. The explanation is surprisingly simple: before reaching our eyes, light from low-lying stars passes through a large thickness of the atmosphere! Accordingly, it is distorted much more strongly.

Do stars in space also tremble and twinkle? Of course not! Flying in orbit around the Earth outside the dense layers of the atmosphere, astronauts observe smooth and calm light stars

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Have you ever noticed how the straight lines on the bottom of a tiled pool seem to sway from side to side? This phenomenon occurs because the water in the pool refracts the rays of light reflected from the bottom of the pool. Similarly, stars twinkle due to turbulence in the Earth's atmosphere. must pass through several kilometers of the earth's atmosphere before reaching the eye of the observer. Here the Earth's atmosphere acts like water in a swimming pool.

Much depends on the air

Why do stars twinkle? Yes, because a lot depends on the air temperature. It usually decreases by 6.5°C with every kilometer we go up. This is why it is cold in the mountains. The Earth's atmosphere consists of several "layers". Each layer has a different temperature and density. Warm air refracts light rays less, and cool air distorts more because in warm air the air molecules are further apart from each other, producing less light scattering.

Our atmosphere is filled with very turbulent currents and vortices of air. These circumstances, coupled with changes in temperature in the atmosphere, act as lenses and prisms that shake the incoming light from the star from side to side, several times per second. This causes a change in brightness and location.

The higher the place for stargazing, the better.

Because of this effect, observatories for studying stars are located on mountain tops. The reason for this is that the higher you go, the thinner the layers of air become and less likely to cause the flickering effect. Scientists are conducting experiments to compensate for the flickering effect by adapting the optics of telescopes. As a result, astronomers will soon be able to see much clearer images of stars here on earth.

Have you noticed that stars located closer to the horizon twinkle more, this is because the atmosphere between you and the stars above the horizon is richer than between you and the star directly overhead.

The telescope was launched in outer space, because there is no atmosphere, which allowed scientists to see clear images of the Universe.

Planets don't twinkle like stars. This is because planets shine with reflected light and are closer than stars, causing less refraction. In fact, this is good way find out whether the object you see in the sky is a planet or a star. For a planet, light that is reflected from a group of points on the planet's disk, and flickers and changes colors. However, the flickering of one part of the planet is complemented by another flickering part of the planet. Thus, the planet appears to glow constantly, and the stars around it twinkle in the sky.

Undoubtedly main star in winter. This brightest diamond literally catches your eye, it is so bright! However, people far from astronomy are still to a greater extent surprises star behavior: Sirius usually flickers strongly and shimmers with all the colors of the rainbow, so quickly that you can’t even tell right away what color it is. Why is this so?

Before we go into explanations, let us assure you that they flicker all stars, not just Sirius. (If you see a very bright, but practically not flickering star in the sky, then most likely it is a planet - Venus or Jupiter.) Those stars that are closer to the horizon twinkle more strongly; those at the zenith, on the contrary, flicker much more weaker.

The same applies to the rapid change of colors: Sirius is not the only one that demonstrates a similar effect, but in the case of this star it is especially striking - simply because Sirius is the brightest star in the night sky and attracts primary attention. And, frankly, in our latitudes Sirius almost always twinkles, since it does not rise high above the horizon.

Behind all these phenomena is earth's atmosphere. The fact is that the air envelope around our planet is not at all homogeneous. On different heights the air has different temperatures, which leads to the formation of air currents, vortices, Hadley cells and other formations. Air cells have different densities due to different temperatures, which means they refract and deflect light passing through them differently. For simplicity, such atmospheric cells can be compared to very weak lenses capable of focusing and deflecting rays of light passing through them.

Stars twinkle much more at the horizon than at the zenith because their light passes through more air. Drawing: Bob King

For this reason, even on the calmest and most transparent night, the light of the stars reaches us at least a little, but distorted. Passing through the turbulent atmosphere, the light of the star will either be focused and completely fall into the eye (and at this moment we will see it bright), or mostly deviate to the side (and then it will dim). We call this rapid fluctuation in brightness flickering.

By the way, the bending of light can be seen directly, if you observe Sirius through a telescope with high magnification. Not only will the star appear in the eyepiece as a spot of light that is not fully focused, but it will also dance from side to side as if it were alive!

But the most striking consequence of this effect is the fact that the star can completely disappear for an instant! Watch Sirius closely for a while on a night when he's twinkling intensely, and you're almost guaranteed to catch one!

The second point is the transfusion of Sirius with all the colors of the rainbow. And this is where it all comes down to atmospheric circulation, because light of different wavelengths bends differently! It turns out that the air behaves like a prism, splitting the star's light into a spectrum! But first one color reaches us, then another, then a third. If we photograph Sirius sequentially with very short exposures, we will see literally the entire palette of colors in the photographs!

A series of instant photographs of Sirius, illustrating the star's chaotic color changes. Sirius appears in circles in the photographs because it was deliberately taken out of focus to show the color more clearly. Photo: Bob King

If you shoot a star with a longer exposure, but at the same time move the camera from side to side so that the star constantly moves in the lens, then Sirius will appear in the photo as a beautiful multi-colored curve.

Scintillations (flickering) of Sirius, filmed through a shaky camera. Photo: www.cosmicriver.net

In fact, the color of Sirius is white. This hot star, the surface temperature of which is almost twice the temperature of the surface of the Sun! IN southern countries, where Sirius rises to the zenith and does not flicker so much, white the stars are visible very clearly.

The starry night sky always evokes special feelings; often all earthly affairs become unimportant, and a person begins to feel like a small part of the vast Universe, part of something larger than just planet Earth.

Why do stars twinkle? Many people have probably asked themselves this question. An incredibly beautiful sight, especially after the rain, when the stars shimmer with all the colors of the rainbow. People don’t always know how to answer such a seemingly childish question.

A simple answer to a simple question

Stellar twinkling is caused directly by air vibrations. Due to the heterogeneity of the Earth's atmosphere, air masses move at unequal speeds, and real currents and streams are formed that differ in temperature properties, density and other parameters. Therefore, starlight passing through the atmosphere can be refracted by the most in different ways. So a semblance of this mysterious flickering appears.

Twinkling star

A twinkling star in the sky is like a light big city, if you look at it from afar. And if the air is saturated with moisture, then the glow will change its trajectory and refract, shimmering with all the colors of the rainbow. The answer to the question of why stars twinkle turns out to be so simple. When the star begins to approach the horizon, refraction occurs even more intensely due to the thickness of the air, thereby making the flickering more distinct.

Can planets twinkle?

Stars differ from planets in a huge number of ways physical characteristics, it is not surprising that these space inhabitants shine in different ways. Even on a beautiful night with many twinkling stars, the light emanating from the planets can be clearly seen solar system. Their light can be described as even and constant. Like the Moon or the Sun, they do not flicker. This can be seen even without an ultra-precise microscope.

Why is this happening? If we take into account the factors that the light of stars, like the light of a planet, must be refracted in the layers of the atmosphere, we can conclude that the stars twinkle pointwise, the planet does the same, but due to the fact that it has many such points, the illusion of an even Sveta. It's all about quantity.

Such different stars

If you look at the stars with the naked eye, they all seem almost the same, differing only in brightness. But this is far from true; if you look more closely, you can even distinguish the stars by color. This applies to the largest and bright stars. For example, the stars Arcturus and Aldebaran are orange, while Betelgeuse and Antares are red. Sirius and Vega are called white, Spica and Regulus are white with a blue tint. There are even yellow giants Capella and

Astronomers associate the color of stars with a parameter such as temperature. Red stars with a surface temperature of up to 4 thousand degrees are considered relatively cold; the hottest are white-blue stars, reaching an incredible temperature of 10-30 thousand degrees Celsius! It becomes completely clear why stars twinkle, with such temperature data they are capable of much.

Why do stars twinkle and do they twinkle at all? The answer to this question depends on how you look at it. If this process is identified with refraction, then it can well be called flicker. But, as you know, the stars themselves do not glow; this is just the impression the viewer gets when watching this interesting phenomenon from Earth. If you contemplate this picture from space, there will be no flickering. According to the astronauts, the stars glow brightly and evenly, and they only wink at those watching who remain on Earth.

>> Why do stars twinkle

It will be interesting for children to know why do stars twinkle different colors in the sky: how many stars can be seen in the sky, refraction of light in the Earth's atmosphere, Hubble.

Let's talk about why stars twinkle in language that children can understand. This information will be useful for children and their parents.

For the little ones and the curious will be interested to hear the answer, especially since the twinkling stars look incredibly beautiful in the sky. What's the matter? If you focus on a specific star, you will notice that it sparkles. To explain to the children process, parents or teachers at school should delve into science and remember “stellar scintillation” (as flicker is called). Without the use of technology, up to 6,000 stars can be distinguished.

Children should know that stars twinkle because we look at them through an atmosphere in which air is constantly moving. The light is refracted (bent) in different directions, which causes these glares.

To give full explanation for children Regarding twinkling stars, it should also be noted that the color of the glow can change. Light itself includes the entire spectrum (red, orange, yellow, green, blue, indigo and violet). It comes to us in the form of a wave at different frequencies (each frequency is a specific color). Since the beam bends at a large angle, it changes speed when entering the atmosphere. This leads to the fact that the sparkle becomes multi-colored. This can be checked by taking a prism. The light will refract and you will get a rainbow.

Then have the youngest The question may arise: why don’t planets twinkle? Because they are located closer to us. The stars are far away, and the light travels a huge distance. But the planets are closer and do not produce their own light, but reflect the sun.

Children should know: what closer stars towards the horizon, the more they flicker. This happens because the atmosphere is thicker in these places. If we were in space, we would not notice any flickering, because the light is not distorted. This is why the Hubble Space Telescope is so important. He is already in space and can study objects without interference.

Earth-based telescopes can also see stars without sparkling. For this purpose, complex mirrors are used that do not stop moving. With their help, light is concentrated into a consistent beam to reduce the influence of atmospheric turbulence. This is called adaptive optics, which helps you see the stars more clearly. Now you understand why stars twinkle. Use our photos, videos, drawings and moving models online to better understand the description and characteristics of space objects.