All stars have a color. From red dwarfs and red giants to white and yellow stars, to blue giants and supergiants. The color of a star depends on temperature. When photons burst from inside a star into space, they have different amounts of energy. can emit infrared, red, blue and ultraviolet light at the same time. They even emit X-rays and.

If the star is cold, less than 3,500 Kelvin, its color will be red. This is because more red photons are emitted than any other in visible light. If the star is very hot, over 10,000 Kelvin, its color will be blue. And again, because there are more blue photons streaming out of the star.

The temperature of the Sun is approximately 6,000 Kelvin. The Sun, and stars like our Sun, appear white. This is because we observe all the different color photons coming from the Sun at the same time. When you add these colors together, you get pure white.

The white color inside this black square is approximately the color of the Sun.

So why does the Sun look yellow here on Earth? Earth's atmosphere scatters sunlight, removing shorter wavelengths of light - blue and violet. Once you remove these colors from the spectrum of light coming from the Sun, it looks yellow. But if you were to fly and look at the Sun from space, the color of the Sun would be pure white.

Sun temperature

The surface of the Sun, the part we can see, is called the photosphere. Photons streaming from the surface of the Sun vary in temperature from 4500 Kelvin to over 6000 Kelvin. The average temperature of the Sun is about 5800 Kelvin. In other units, the Sun is 5500°C or 9,900°F.

Photosphere of the Sun. Credit: NASA/SOHO.

But this is only the average temperature. Individual photons can be colder and redder, or hotter and bluer. The color of the Sun that we see here on Earth is, on average, all the photons streaming from the Sun.

But that's just the surface. The sun is held together by the mutual gravity of its mass. If you could go down below the Sun, you would feel the temperature and pressure increase all the way to the core. And down to the core temperatures reach 15.7 million Kelvin. At such a pressure and temperature, hydrogen nuclear fusion can already take place. This is where hydrogen atoms fuse together to form helium, releasing photons of gamma radiation. These photons are released and absorbed by atoms in the Sun as they slowly make their way into space. It may take 100,000 years for a photon produced in the nucleus to eventually reach the photosphere and jump into space.

Sun surface

Perhaps the most familiar feature on the surface of the Sun is sunspots. These are relatively colder regions on the Sun's surface where magnetic field lines pierce the Sun's surface. Sunspots can be the source of solar flares and coronal mass ejections.


View of the surface of the Sun from the scientific Japanese satellite Hinode.

When we look at the Sun, we notice that the center of the Sun looks much brighter than the edges. This is called "limb dimming" and happens because we're seeing light that has passed through the Sun's surface at an angle, and has more obstruction - and is therefore darker.

With a good telescope (and even a better solar filter), it is possible to see that the photosphere is not smooth. Instead, it is covered in convection cells called granules. They are caused by convective plasma flows inside the Sun's convection zone. Hot plasma rises in columns through this convection region of the Sun, releases its energy and then cools and sinks. Imagine bubbles rising to the surface in boiling water. These granules can be 1000 km wide and last 8-20 minutes before dissipating.

Huge coronal mass ejections can also be seen shooting from the surface of the Sun. They are created when the sun's coiled magnetic field abruptly breaks off and separates. This decoupling releases an enormous amount of energy, and ejects charged plasma into space. When this plasma reaches the Earth, it creates beautiful aurorae, best seen at the Earth's poles.

Luminosity of the Sun

Astronomers measure the brightness of stars with various instruments, but they need a way to compare. This is where our Sun appears. As everyone knows, the Sun gives off approximately 3.839 x 10 33 erg per second of energy. Other stars in the universe can only give off a fraction of the solar luminosity, or a few multiples of it. Our Sun is the stellar criterion.


Massive coronal mass ejection. This photo shows the size of the Earth for comparison (top left). Credit: NASA/SDO/J. Major.

Imagine that the Sun is surrounded by rows of transparent spheres - like the layers of an onion. The amount of energy, the solar luminosity, passing through each of these spheres every second is always the same. However, the surface area of ​​the sphere is getting bigger and bigger. This is why the farther away you get from the star, the less light you see.

This is called the inverse square law, and allows astronomers to calculate the solar luminosity; in fact, it allows them to calculate the luminosity of all stars. Scientists have sent missions into space that measure the total amount of energy falling on their sensors. From this information, astronomers can calculate how much energy falls on the entire Earth, and then how much comes from the Sun.

And it also works for stars. The spacecraft detects the luminosity of another star, factors in distance, and helps calculate the star's original luminosity.

Although our Sun is stable, it experiences minor changes in solar luminosity. These changes are caused by sunspots that darken regions and bright structures on the solar disk during the 11-year solar cycle. Detailed measurements over the past 30 years have found that they are not sufficient to lead to the acceleration of global warming that we are experiencing here on Earth.

We rarely think about the color of our natural star that illuminates the Earth during the day. Thinking about it now, most people will say either yellow or white. And I must say that they are all partly right.

The fact is that due to the presence of many different factors and aspects, the color of the Sun changes. However, in reality, the luminary has a white color. And today we will understand why the Sun is white.

Does the sun change color?

The first step is to deal with the color changes of our luminary. Of course, when it comes to the fact that the Sun changes its color, we really mean an optical illusion, because this star has only one static shade of color.

The reason that we are able to observe different color shades of the Sun, ranging from white to scarlet red, is our atmosphere. The specificity of our atmosphere is such that the light passing through it experiences a kind of filtering, and longer wavelengths of the color spectrum pass through it much better than short-type waves. And the long waves, by the way, include the colors of the yellow-red segment.

As for what directly affects the shade in which we have the opportunity to observe our natural luminary at certain points in time, this is, first of all, the composition of our atmosphere. In addition, all kinds of chemicals, gas emissions into the atmosphere, caused by man, have a fairly significant effect on the visible color.

Why is the sun white

As we have already noted above, often our natural luminary has a yellowish or even orange tint. Probably most people are accustomed to this color scheme. However, sometimes we have the opportunity to observe a completely white Sun, and here a completely logical question arises as to why the Sun is suddenly white.

The most interesting thing in this situation is that the natural color of this star is just white. And if we have the opportunity to observe the Sun in such a shade, it only means that its rays made their way through our atmosphere to our views with minimal distortion.

By the way, in deserts and on distant islands, which are as far as possible from all kinds of industrial emissions and gases, the Sun is almost always white, because the sky is absolutely not polluted there.

Even from a young age, a child looks at the sun's rays, understands that they are blinding, sees sunsets and sunrises, and sooner or later wonders why the Sun is yellow.


Not every adult is able to explain the reason for the solar yellowness, because for this it is necessary not only to know what our star is, but also to have at least a rough idea of ​​​​its structure and properties.

What is the Sun?

The Sun is the only star in the galaxy in which our Earth is located. Many other satellites, asteroids, and other celestial bodies that make up the solar system revolve around it.

Scientists still cannot reliably establish the history of its occurrence, but according to one of the most common theories, the Sun appeared as a result of the explosion of one or more supernovae about 4.57 billion years ago.

In addition to the Sun, there are many other stars in the Universe, which are divided into several varieties. Scientists distinguish between red giants, white and brown dwarfs, new, supernovae stars.


Our star belongs to yellow dwarfs, that is, to the type of small stars with a surface temperature of 5000 to 6000 kelvin and an average life of about 10 billion years. As their name suggests, they are yellow, which is one of the reasons why the Sun is considered yellow.

Why does the sun shine?

The Sun has a huge mass (more than 99% of the mass of the entire solar system) and contains over 73% of hydrogen in its composition. Thermonuclear reactions constantly occur on the solar surface, as a result of which helium is released from hydrogen.

Previously, scientists believed that the star shines due to the combustion of the elements that make up its composition, but not so long ago they managed to prove that it is thanks to thermonuclear reactions that the star maintains its temperature and emits an enormous amount of energy.

Solar radiation is the main source of life on Earth. Without it, there would be neither plants, nor animals, nor people themselves on our planet. And although the distance between the Earth and the Sun is almost 150 million kilometers, due to the high temperature and brightness, the sun's rays easily overcome this gap.


When passing through the atmosphere, they lose about one-third of the energy, but what reaches the surface is quite enough for the existence of all life.

Why is the sun yellow?

In children's drawings, the Sun is always painted yellow, but in reality it has a dazzling white color. Its yellowness is explained by the fact that when passing through the atmosphere, part of the spectrum of sunlight is absorbed.

They partially scatter without losing their wavelengths. Another reason lies in the peculiarities of the structure of the human eye. The perception of yellow is due to an optical effect in which we see a white Sun in yellow tones against a blue sky.

The human eye is designed in such a way that it perceives only 3 colors - green, blue, red. In sunlight, our pupils react to the waves of these particular shades. However, some rays are longer, others are shorter.

Those that are shorter dissipate faster and are perceived by the eye much more strongly. For example, blue atmospheric rays are the shortest, so we see the sky blue. The white rays of the sun are longer, and when they enter the atmosphere, they combine with blue rays, so that we see them as yellow.

Why is the sun different colors?

In addition to yellow and white, the Sun can have other shades. Sometimes it is seen red, sometimes purple or orange. Why is this happening? The red or orange Sun is usually at sunset or dawn.


Since the Earth rotates on its axis, during these periods the star is at a more distant distance from our planet. In order to reach the earth's surface, in the morning and in the evening the sun's rays have to travel a little further than in the daytime.

Because of this, they scatter more and mix with more blue waves, as a result, our eye perceives them as red or orange. The lilac (violet) color of the sun usually occurs when it is covered by a veil of black smoke, for example, during volcanic eruptions.

"I came into this world

To see the Sun and the blue outlook.

I came into this world

To see the Sun and the heights of the mountains.

Our planet and earthly inhabitants cannot exist without the familiar, warm solar ball. A person is sad in cloudy weather, and when the sun shimmers cheerfully in the sky, the fiery luminary inspires hope and confidence that everything will be fine. Why is the sun yellow? Have you thought about it?

What is the Sun

The solar star is a hot ball of gas, the central figure of the solar system. The center of the cluster of planets, celestial bodies, consisting of heavy elements. Hydrogen in the composition of the Sun is compressed under the influence of gravitational forces. Inside the star, a thermonuclear reaction continuously proceeds, creating helium from hydrogen.

The solar star arose after a series of supernova explosions five billion years ago. Thanks to the ideal location to the Sun, life originated on the third planet. This is Earth.

Helium leaks and radiates through the photosphere (the thin surface layer of a star) into outer space. The star has a boundary atmosphere - the solar corona, which merges with the interstellar medium. We cannot see the corona because the gas is very rarefied. It becomes visible during eclipses.

The main luminary of the solar system has the 11th cycle of activity. During this period, the number of sunspots (darkened zones of the photosphere), flares (dazzling glows of the chromosphere), prominences (hydrogen clouds condensing in the corona) increases/decreases.

The chromosphere is the boundary layer between the photosphere and the corona. A person sees it during solar eclipses in the form of a bright red rim. The mass of the star is gradually decreasing. A star loses some of its weight when converting hydrogen into helium (synthesizing energy).

The warmth that pleases people is the lost stellar mass (sun rays). Weight is also lost due to the winds on the Sun, regularly blowing the star's electrons and protons into space.

Why is the heavenly body yellow?

Not every person is able to explain the reason for the pleasant, warm shade of a solar star. A scientific explanation requires knowledge about the structure of celestial bodies, the properties of the earth's atmosphere, and the abilities of the human eye. The explanation why the Sun is yellow is given from two perspectives.

beautiful illusion

In fact, the color of the sun star is white. But human eyes stubbornly present a shade of yellow. This is the color perception of light waves in humans. When the sun's rays pass through the earth's atmosphere, they lose part of the light spectrum, but retain their wavelength.

Nature arranged the human eye in a cunning way. We perceive only three colors: blue, red, green.

Some spectral radiations are long, others are shorter. A short spectrum of waves scatter at a faster rate, people perceive them more sensitively. The shortest color spectrum consists of blue wavelengths. Therefore, the sky seems to be a noble blue hue.

The white rays of the Sun are longer. When they penetrate the atmosphere and merge with the blue spectrum, the result is the yellow color that we see. The more piercing the shade of the sky, the brighter, the more yellow the luminary seems. Please note - such an optical effect is noticeable after rain in cloudless weather.

And in winter, when the sky is gloomy, bleak, the sun dims and is perceived by people as a whitish circle.

Astronomy speaks

What color is the Sun according to astronomers? The warm luminary is the "yellow dwarf". This is the type of star that determines the size. Compared to other stars in the Galaxy, the solar star is tiny, and the gamut of its color radiance is yellow.

The color of the radiance of a star depends on the size, distance from the Earth, and the characteristics of the chemical reactions taking place inside.

The young star has a bright glow and long light pulses of a certain frequency. Such "newborn" stars have a sparkling white with a blue glow (young stars are white). Our middle-aged sunny lady has rays of a different frequency and is perceived by people as yellow.

For astronomers, the color of the sun is important. Using a special spectroscope device, scientists study other stars by spectral decomposition. The composition is determined (metal or helium with hydrogen left in space after the Big Bang). Understand the surface temperature of the stars.

  • Cold red stars (Gliese, Arcturus, Cepheus, Betelgeuse).
  • The hot ones (Rigel, Zeta Orion, Alpha Giraffe, Tau Canis Major) have a glow of a pleasant bluish tint.

Outside the atmosphere, the Sun looks like a white star. The color of the bewitching heavenly beauties is surprisingly diverse. From white-blue to crimson-red. The hotter the star, the longer the wavelength range.

Blue has shorter wavelengths than red. Therefore, hot stars radiate more strongly in the blue range and appear blue, while cold stars pierce the red spectrum more powerfully, we see them in a red hue.

Interesting fact. Why the sun is yellow was explained in 1871. British physicist John Rayleigh created the theory of molecular scattering of a light beam. The law that explains the intensity of light scattered by air was named after him - Rayleigh's law.

Explanation for children

The mind of children is inquisitive and inquisitive. The young "why" asks thousands of questions. Sometimes adults get lost, choosing the answer so that the baby understands better. How to explain obvious things to a small person (why the sun shines, why is it yellow, and the sky is blue)? How to choose words so as not to scare away with abstruse phrases, but to push the little researcher to study and knowledge? Consider the age of the child in the explanation.

We explain to kids. It’s too early to talk to little children about the spectra of colors, light waves. Come up with a fascinating fairy tale to satisfy the curiosity of the crumbs.

“In the world lived a fairy-tale wizard. He loved to draw, and wore magic colors all the time. Every morning he painted the sky blue and the sun yellow, so that people would be cheerful, warm and joyful. The magician has an older fairy sister. She watches over him, and in the evenings, when the children get tired, the fairy wraps the sky, the sun in a dark blanket and scatters the stars so that the kids have wonderful dreams.

When a wizard is sad, his colors also cry. Then the blue color of the sky is blurred, hiding the sun. It becomes sad, but not for long. The fairy sister comes to the aid of the magician, draws a multi-colored rainbow and again paints the sun, giving it a golden ray. After all, wizards do not know how to be sad!

Or this story: “Once upon a time there were magical colors. They loved to walk and went outside every day. Once they woke up in the morning, ran out into the yard - and there everything was gray, dull! It doesn’t matter, said the paints, we will return the colors! Blue painted the sky, puddles, river - let the kids splash in the water!

Yellow went to decorate the sun so that it would become warm and warm everyone around. Green decorated grass, trees, black - pebbles, earth. Then the paints painted the flowers together - look how colorful they are! The colors worked well, they got tired, they went to sleep. And on the street, everything remained painted - after all, the colors are magical!

Older kids. Older children can be explained why the Sun seems yellow, in adult language, but in accessible words:

"Remember the rainbow? It has seven colors. But in the rainbow, the colors go separately, one after another. The light of a solar star is the same rainbow, but the colors of a bright star are connected, mixed. The sun is far away from us and launches the sun's rays towards our planet.

The sky has an atmosphere, it is like a sieve. Sunlight, reaching the Earth, “splashes into separate colors (like a rainbow). Rays pass through the heavenly "sieve" in different ways. They are fast, while other colors are so lazy that they don’t even reach us and “get stuck” in the strainer atmosphere. The most persistent, strong - blue and yellow rays. Therefore the sun is yellow and the sky is blue. This is how we see them."

Come up with your own answers, turn on your imagination, awaken the storytellers in yourself!

"Colorful" star

If you are one of the observant people, then you know that the Sun comes in a different color. Not only yellow or whitish. Before leaving or ascending into the sky, a solar star shines with an orange, purple or reddish hue.

Why was it red at sunset and pink at dawn? Our planet rotates around its axis, receding and approaching the Sun. In the evening, morning, the Earth occupies the most distant distance from the hot star.

In order to reach the earth's surface in the evening or in the morning, the sun's rays spend more time traveling. On the way, they dissipate faster, mixing with more color waves of a blue tint. Therefore, at this time the Sun is a different color.

If a hot star is covered by a black cloud of ash or smoke (during a strong fire, volcanic eruption), the star will acquire a purple-violet, frightening hue. The more dust in the air, the richer the hue of the star becomes. Microscopic dust particles pass only violet and red light waves, they "take" the rest of the spectrum, absorb it.

The same thing happens when the humidity rises. Water vapor transmits only red spectral waves. Therefore, during a period of high humidity, before heavy rain, the sun star acquires a red hue.

Do not be alarmed when the familiar yellow sun appears before us in a different color guise. These are "jokes" of human visual perception, an optical effect. Any shade of the Sun is explainable, and does not pose any threat to people.

Interesting observations!

The answer to the question "What color is the Sun really?" seems obvious - yellow. To be convinced of this, it is enough to raise your eyes to the blue sky on a clear day and see a bright yellow circle ... But not everything is as simple as it seems at first glance.

The true color of the Sun is white. But the star appears yellow to us because of our planet's atmosphere. The fact is that the white color of the Sun is obtained as a result of a combination of light waves of different lengths. And if you decompose the waves one by one, you get a kind of rainbow - the length of each wave will indicate its color. The shorter the wavelength, the more likely the light wave will hit a gas molecule in the atmosphere and bounce off in the other direction, in other words, will dissipate. But long-wavelength colors easily bypass gas molecules and reach the retina of our eye. If you look at the picture below, it becomes clear why we observe the Sun is yellower than it really is. Blues and purples dissipate while reds and yellows reach the surface.

If the Sun is declining, then its rays are directed tangentially to the earth's surface, and they need to overcome a much greater distance through the atmosphere. Accordingly, even more light waves will be scattered by the atmosphere and the most persistent and reddest colors will reach us.

Where does the color of short light waves go? It scatters in the layers of the atmosphere in different directions many times, which is why the sky takes on a blue tint. The higher from the ground, the darker it becomes around - there are fewer gas molecules that scatter light. Now we know why our sky is blue.

But after all, judging by the picture with the lengths, the waves of purple are shorter than the waves of blue or cyan. Why isn't our sky purple then? Here our eyes play a big role, which are much more sensitive to shades of blue than purple. In addition, most violet rays are scattered in the upper atmosphere.


As you can see from the article, to answer seemingly simple questions, like "What color is the Sun?" or “Why is the sky blue?”, mankind had to advance far in their knowledge of physics, chemistry and astronomy. Modern science helps us take a fresh look at familiar things that people who lived several centuries ago did not even think about.

It is interesting: traffic lights, emergency lights and all kinds of signal beacons glow red for a reason. It is this color that is least scattered in the earth's atmosphere.

Illustration: Paul Paladin | bigstockphoto.com

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