Who does not like to admire the most beautiful view of the starry sky at night, look at thousands of bright and not very stars. About why the stars shine, our article will tell.

Stars are cosmic objects that emit a huge amount of heat energy. Such a large release of heat energy, of course, is accompanied by strong light radiation. The light that has reached us, we can observe.

When you look at the starry sky, you will notice that most of the stars are different. Some stars shine with the past, others with blue light. There are also stars that shine orange. Stars are large balls of very hot gases. Since they are heated differently, they have a different glow color. So, the hottest ones shine with blue light. Stars that are slightly colder are white. Even colder stars shine yellow. Then come the "orange" and "red" stars.

It seems to us that the stars twinkle with an unstable light, and the planets shine with a steady and steady light. Actually it is not. Stars do not twinkle, but we think so because the light of stars passes through the thickness of our earth's atmosphere. As a result of this, a ray of light, having overcome the distance from the star itself to the surface of our planet, undergoes a large number of refractions, changes, and much more.

Our Sun is also a star, although not very big and bright. Compared to other stars, the Sun occupies an average position according to the above parameters. Many millions of stars are much smaller than our Sun, while other stars are many times larger than it.

But why do stars glow at night? In fact, the stars shine not only at night, but also during the day. However, in the daytime, they are not visible to us because of the Sun, which brightly illuminates the entire surface of our planet with its rays, and space and stars are hidden from our view. In the evening, when the Sun sets, this veil opens slightly, and we can see the radiance of the stars until the morning, until the Sun rises again.

Now you know why the stars shine!

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Why do the stars shine

INTRODUCTION

astronomy star universe

By the beginning of our century, the boundaries of the explored Universe had expanded so much that they included the Galaxy. Many, if not all, thought then that this huge star system is the entire Universe as a whole.

But in the 1920s, new large telescopes were built, and completely unexpected horizons opened up before astronomers. It turned out that the world does not end outside the Galaxy. Billions of star systems, galaxies similar to ours and different from it, are scattered here and there throughout the expanses of the Universe.

Photographs of galaxies taken with the largest telescopes are striking in their beauty and variety of forms: these are mighty whirlwinds of star clouds, and regular balls, while other star systems do not show any definite forms at all, they are ragged and shapeless. All these types of galaxies are spiral, elliptical, irregular - named after their appearance in photographs, discovered by the American astronomer E. Hubble in the 20-30s of our century.

If we could see our Galaxy from afar, then it would appear before us not at all the same as in the schematic drawing. We would not see a disk, a halo, and, of course, a crown. From great distances, only the brightest stars would be visible. And all of them, as it turned out, are collected in wide bands that arc out from the central region of the Galaxy. The brightest stars form its spiral pattern. Only this pattern would be distinguishable from afar. Our Galaxy in a picture taken by an astronomer from some stellar world would look very similar to the Andromeda Nebula.

Research recent years showed that many large spiral galaxies, like our Galaxy, have extended and massive invisible coronas. This is very important: after all, if so, then, in general, almost the entire mass of the Universe (or, in any case, the overwhelming part of it) is a mysterious, invisible, but gravitating hidden mass

Many, and perhaps almost all, galaxies are collected in various collectives, which are called groups, clusters and superclusters, depending on how many there are. A group may include only three or four galaxies, and a supercluster may contain up to a thousand or even several tens of thousands. Our Galaxy, the Andromeda Nebula and more than a thousand of the same objects are included in the so-called Local Supercluster. It does not have a clearly defined shape.

The heavenly bodies are in constant motion and change. When and how exactly they occurred, science seeks to find out by studying the celestial bodies and their systems. The branch of astronomy that deals with the origin and evolution of celestial bodies is called cosmogony.

Modern scientific cosmogonic hypotheses are the result of physical, mathematical and philosophical generalization of numerous observational data. In the cosmogonic hypotheses inherent in this era, to a large extent is reflected general level development of natural science. The further development of science, which necessarily includes astronomical observations, confirms or refutes these hypotheses.

In this work, the following questions are considered:

· The structure of the universe is presented, the characteristics of its main elements are given;

Shows the main methods of obtaining information about space objects;

The concept of a star, its characteristics and evolution is defined

The main sources of stellar energy are presented

Description of the closest star to our planet - the Sun

1. HISTORICAL DEVELOPMENT OF CONCEPTS ABOUT THE UNIVERSE

Even at the dawn of civilization, when the inquisitive human mind turned to sky-high heights, great philosophers thought of their idea of the Universe as something infinite.

The ancient Greek philosopher Anaximander (6th century BC) introduced the idea of a certain unified infinity that did not have any of the usual observations and qualities. The elements were thought at first as semi-material, semi-divine, spiritualized substances. So, he said that the beginning and element of being is the Infinite, giving the first name to the beginning. In addition, he spoke of the existence of perpetual motion, in which the creation of the heavens takes place. The earth, on the other hand, floats in the air, supported by nothing, but remains in place due to an equal distance from everywhere. Its shape is curved, rounded, similar to a segment of a stone column. On one of its planes we walk, the other is on opposite side. The stars are a fiery circle, separated from the world fire and surrounded by air. But in the air shell there are vents, some kind of tubular, i.e., narrow and long holes, in the downward direction from which the stars are visible. As a result, when these vents are blocked, an eclipse occurs. The moon, on the other hand, seems either full or at a loss, depending on the closing and opening of the holes. The solar circle is 27 times larger than the earthly and 19 times larger than the lunar one, and the sun is above everything, and behind it the moon, and below all the circles of fixed stars and planets. Another Pythagorean Parmenides (VI-V cc. AD). Heraclid Pontus (V-IV century BC) also claimed its rotation around its axis and conveyed to the Greeks the even more ancient idea of the Egyptians that the sun itself could serve as the center of rotation of some planets (Venus, Mercury).

The French philosopher and scientist, physicist, mathematician, physiologist Rene Descartes (1596-1650) created a theory about the evolutionary vortex model of the Universe based on heliocentralism. In his model, he considered celestial bodies and their systems in their development. For the XVII century. his idea was extraordinarily bold.

According to Descartes, all celestial bodies were formed as a result of vortex movements that occurred in the homogeneous at the beginning, world matter. Absolutely identical material particles, being in continuous motion and interaction, changed their shape and size, which led to the rich diversity of nature that we observe.

The great German scientist, philosopher Immanuel Kant (1724-1804) created the first universal concept of the evolving Universe, enriching the picture of its even structure and representing the Universe as infinite in a special sense.

He substantiated the possibility and significant probability of the emergence of such a universe solely under the influence of mechanical forces attraction and repulsion and tried to find out the further fate of this Universe at all its scale levels - from the planetary system to the world of the nebula.

Einstein made a radical scientific revolution by introducing his theory of relativity. Einstein's special or particular theory of relativity was the result of a generalization of Galileo's mechanics and Maxwell Lorentz's electrodynamics.

It describes the laws of all physical processes at speeds close to the speed of light. For the first time, fundamentally new cosmological consequences general theory relativity was revealed by the outstanding Soviet mathematician and theoretical physicist Alexander Fridman (1888-1925). Speaking in 1922-24. he criticized Einstein's findings that the universe is finite and shaped like a four-dimensional cylinder. Einstein made his conclusion based on the assumption of the stationarity of the Universe, but Friedman showed the groundlessness of his original postulate.

Friedman gave two models of the universe. Soon, these models found surprisingly accurate confirmation in direct observations of the movements of distant galaxies in the effect of "redshift" in their spectra. In 1929, Hubble discovered a remarkable pattern, which was called "Hubble's law" or "redshift law": lines of galaxies shifted to the red end, and the shift is greater, the farther away the galaxy is.

2. TOOLS OF OBSERVATION ASTRONOMY

telescopes

The main astronomical instrument is the telescope. A telescope with a concave mirror lens is called a reflector, and a telescope with a lens lens is called a refractor.

The purpose of a telescope is to collect more light from celestial sources and increase the angle of view from which a celestial object is visible.

The amount of light that enters the telescope from the observed object is proportional to the area of the lens. The larger the lens of a telescope, the fainter luminous objects can be seen through it.

The scale of the image given by the lens of the telescope is proportional to the focal length of the lens, i.e., the distance from the lens that collects light to the plane where the image of the star is obtained. An image of a celestial object can be photographed or viewed through an eyepiece.

The telescope increases the apparent angular dimensions of the Sun, the Moon, the planets and details on them, as well as the angular distances between the stars, but the stars, even with a very strong telescope, are visible only as luminous points due to their great distance.

In the refractor, the rays, passing through the lens, are refracted, forming an image of the object in the focal plane . In a reflector, rays from a concave mirror are reflected and then also collected in the focal plane. In the manufacture of a telescope lens, they strive to minimize all the distortions that the image of objects inevitably has. A simple lens greatly distorts and colors the edges of the image. To reduce these shortcomings, the lens is made from several lenses with different surface curvature and from different types of glass. To reduce distortion, the surfaces of a concave glass mirror are given not a spherical shape, but a slightly different (parabolic) one.

Soviet optician D.D. Maksutov developed a telescope system called the meniscus. It combines the advantages of a refractor and a reflector. According to this system, one of the models of the school telescope is arranged. There are other telescopic systems.

The telescope produces an inverted image, but this does not matter when observing space objects.

When observing through a telescope, magnifications over 500 times are rarely used. The reason for this is air currents, which cause image distortions, which are more noticeable, the greater the magnification of the telescope.

The largest refractor has a lens with a diameter of about 1 m. The world's largest reflector with a concave mirror diameter of 6 m was made in the USSR and installed in the Caucasus mountains. It allows you to photograph stars 107 times fainter than those visible to the naked eye.

Spectral charter

Until the middle of the XX century. our knowledge of the universe was due almost exclusively to mysterious light rays. A light wave, like any other wave, is characterized by a frequency x and a wavelength l. There is a simple relationship between these physical parameters:

where c is the speed of light in vacuum (emptiness). And the photon energy is proportional to the radiation frequency.

In nature, light waves propagate best in the vastness of the universe, since there is the least interference on their path. And a man, armed with optical instruments, learned to read the mysterious light writing. With the help of a special device - a spectroscope adapted to a telescope, astronomers began to determine the temperature, brightness and size of stars; their speeds, chemical composition and even the processes occurring in the depths of distant luminaries.

Isaac Newton also established that white sunlight consists of a mixture of rays of all colors of the rainbow. When passing from air to glass, color rays are refracted in different ways. Therefore, if a trihedral prism is placed in the path of a narrow solar ray, then after the beam leaves the prism, a rainbow strip appears on the screen, which is called the spectrum.

Spectrum contains essential information about a celestial body that emits light. It can be said without any exaggeration that astrophysics owes its remarkable successes primarily to spectral analysis. Spectral analysis is nowadays the main method for studying the physical nature of celestial bodies.

Each gas, each chemical element gives its own lines in the spectrum, only to it alone. They may be similar in color, but necessarily differ from one another in their location in the spectral strip. In a word, the spectrum of a chemical element is its kind of "passport". And an experienced spectroscopist only needs to look at a set of colored lines to determine which substance emits light. Consequently, in order to determine the chemical composition of a luminous body, there is no need to pick it up and subject it to direct laboratory research. Distances here, even if they are space, are not a hindrance either. It is only important that the body under study be in a hot state - it glows brightly and gives a spectrum. When examining the spectrum of the Sun or another star, the astronomer is dealing with dark lines, the so-called absorption lines. The absorption lines coincide exactly with the emission lines of the given gas. It is because of this that absorption spectra can be used to study the chemical composition of the Sun and stars. By measuring the energy emitted or absorbed in individual spectral lines, it is possible to carry out a quantitative chemical analysis heavenly bodies, that is, to learn about percentage various chemical elements. So it was found that hydrogen and helium predominate in the atmospheres of stars.

A very important characteristic of a star is its temperature. As a first approximation, the temperature of a heavenly body can be judged by its color. Spectroscopy makes it possible to determine the surface temperature of stars with very high accuracy.

The temperature of the surface layer of most stars lies in the range from 3000 to 25000 K.

The possibilities of spectral analysis are almost inexhaustible! He convincingly showed that the chemical composition of the Earth, Sun and stars is the same. True, there may be more or less of some chemical elements on individual celestial bodies, but the presence of some special “unearthly substance” has not been found anywhere. The similarity of the chemical composition of celestial bodies serves as an important confirmation of the material unity of the Universe.

Astrophysics - a large branch of modern astronomy - deals with the study physical properties and chemical composition of celestial bodies and the interstellar medium. She develops theories of the structure of celestial bodies and the processes occurring in them. One of the most important tasks facing astrophysics today is to clarify the internal structure of the Sun and stars and their energy sources, to establish the process of their emergence and development. And all the richest information that comes to us from the depths of the Universe, we owe to the messengers of distant worlds - the rays of light.

Everyone who has observed the starry sky knows that the constellations do not change their shape. Ursa Major and Ursa Minor look like a bucket, the Cygnus constellation looks like a cross, and the zodiac constellation Leo resembles a trapezoid. However, the impression that the stars are fixed is misleading. It is created only because the heavenly lights are very far from us, and even after many hundreds of years the human eye is not able to notice their movement. Currently, astronomers measure the proper motion of stars from photographs of the starry sky taken at intervals of 20, 30 or more years.

The proper motion of stars is the angle that a star moves across the sky in one year. If the distance to this star is also measured, then its own speed can be calculated, that is, that part of the speed of the celestial body that is perpendicular to the line of sight, namely, the “observer-star” direction. But in order to get the full speed of the star in space, it is also necessary to know the speed directed along the line of sight - towards or away from the observer.

Fig.1 Determination of the spatial velocity of a star at a known distance to it

The radial velocity of a star can be determined from the location of the absorption lines in its spectrum. As you know, all lines in the spectrum of a moving light source are displaced in proportion to the speed of its movement. In a star flying towards us, the light waves are shortened and the spectral lines are shifted to the violet end of the spectrum. As a star moves away from us, the light waves lengthen and the lines shift towards the red end of the spectrum. In this way, astronomers find the speed of the star along the line of sight. And when both velocities (natural and radial) are known, then it is not difficult to calculate the total value using the Pythagorean theorem. spatial speed stars relative to the sun.

It turned out that the speeds of the stars are different and, as a rule, are several tens of kilometers per second.

Having studied own movements stars, astronomers were able to imagine the appearance of the starry sky (constellation) in the distant past and in the distant future. The famous "ladle" of the Big Dipper in 100 thousand years will turn, for example, into an "iron with a broken handle."

Radio waves and radio telescopes

Until recently, celestial bodies were studied almost exclusively in the visible rays of the spectrum. But in nature there are still invisible electromagnetic radiation. They are not perceived even with the help of the most powerful optical telescopes, although their range is many times wider than the visible region of the spectrum. So, behind the violet end of the spectrum are invisible ultraviolet rays, which actively affect the photographic plate - causing it to darken. Behind them are X-rays and finally, gamma rays, with the shortest wavelength.

To capture the radio emission coming to us from space, special radio-physical devices are used - radio telescopes. The principle of operation of a radio telescope is the same as that of an optical one: it collects electromagnetic energy. Only instead of lenses or mirrors, antennas are used in radio telescopes. Very often, the antenna of a radio telescope is constructed in the form of a huge parabolic bowl, sometimes solid, and sometimes trellis. Its reflective metal surface concentrates the radio emission of the observed object on a small receiving antenna-feed, which is placed at the focus of the paraboloid. As a result, weak alternating currents arise in the irradiator. By waveguides electric currents transmitted to a very sensitive radio receiver tuned to the operating wavelength of the radio telescope. Here they are amplified, and by connecting a loudspeaker to the receiver, one could listen to the "voices of the stars." But the voices of the stars are devoid of any musicality. These are not “cosmic melodies” that enchant the ear at all, but a crackling hiss or a piercing whistle ... Therefore, a special self-recording device is usually attached to the receiver of a radio telescope. And now, on a moving tape, the recorder draws a curve of the intensity of the input radio signal of a certain wavelength. Consequently, radio astronomers do not "hear" the rustle of the stars, but "see" it on graph paper.

As you know, with an optical telescope we observe at once everything that falls into its field of view.

With a radio telescope, the situation is more complicated. There is only one receiving element (feeder), so the image is built line by line - by sequentially passing the radio source through the antenna beam, that is, similar to the way it is on a television screen.

Wine Law

Wine Law- the dependence that determines the wavelength during the radiation of energy by a completely black body. It was bred by a German physicist, Nobel laureate Wilhelm Wien in 1893.

Wien's Law: The wavelength at which a black body radiates the most energy is inversely proportional to that body's temperature.

A black body is a surface that completely absorbs radiation falling on it. The concept of a black body is purely theoretical: in reality, objects with such an ideal surface that completely absorbs all waves do not exist.

3. MODERN CONCEPTS ON THE STRUCTURE, MAIN ELEMENTS OF THE VISIBLE UNIVERSE AND THEIR SYSTEMATIZATION

If we describe the structure of the Universe, as it seems to scientists now, then we get the following hierarchical ladder. There are planets - celestial bodies that orbit around a star or its remnants, massive enough to become rounded under the influence of their own gravity, but not massive enough to start a thermonuclear reaction, which are "tied" to a particular star, that is, they are in its zone gravitational influence. So, the Earth and several other planets with their satellites are in the zone of gravitational influence of a star called the Sun, move in their own orbits around it and thereby form the solar system. Such star systems, which are nearby in huge numbers, form a galaxy - a complex system with its own center. By the way, regarding the center of galaxies there is no consensus yet what they are - it is suggested that black holes are located in the center of galaxies.

Galaxies, in turn, make up a kind of chain that creates a kind of grid. The cells of this grid are made up of chains of galaxies and central "voids", which are either completely devoid of galaxies or have a very small number of them. The main part of the Universe is occupied by vacuum, which, however, does not mean the absolute emptiness of this space: there are also individual atoms in the vacuum, there are photons (relic radiation), and particles and antiparticles appear as a result of quantum phenomena. The visible part of the Universe, that is, that part of it that is accessible to the study of mankind, is characterized by homogeneity and constancy in the sense that, as is commonly believed, the same laws operate in this part. Whether this is also the case in other parts of the universe is impossible to determine.

In addition to planets and stars, the elements of the Universe are such celestial bodies as comets, asteroids and meteorites.

A comet is a small celestial body revolving around the Sun in a conic section with a very stretched orbit. When approaching the Sun, a comet forms a coma and sometimes a tail of gas and dust.

Conventionally, a comet can be divided into three parts - the core, coma, tail. Everything in comets is absolutely cold, and their glow is only the reflection of sunlight by dust and the glow of ultraviolet-ionized gas.

The core is the heaviest part of this celestial body. It contains the bulk of the comet's mass. It is rather difficult to study the composition of the comet nucleus precisely, since at a distance accessible to the telescope, it is constantly surrounded by a gaseous mantle. In this regard, the theory of the American astronomer Whipple was adopted as the basis for the theory of the composition of the comet nucleus.

According to his theory, the nucleus of a comet is a mixture of frozen gases mixed with various dusts. Therefore, when a comet approaches the Sun and heats up, the gases begin to "melt", forming a tail.

The tail of a comet is its most expressive part. It is formed near a comet as it approaches the Sun. The tail is a luminous strip that stretches from the nucleus in the opposite direction from the Sun, "blown away" by the solar wind.

A coma is a cup-shaped light cloudy shell surrounding the nucleus, consisting of gases and dust. Usually stretches from 100 thousand to 1.4 million kilometers from the core. Light pressure can deform the coma, stretching it in the antisolar direction. The coma, together with the nucleus, makes up the head of the comet.

Asteroids are called celestial bodies, which have a mostly irregular stone-like shape, ranging in size from a few meters to thousands of kilometers. Asteroids, like meteorites, are composed of metals (mainly iron and nickel) and stony rocks. In translation latin word asteroid means "like a star". Asteroids got this name for their resemblance to stars when observing them with not very powerful telescopes.

Asteroids can collide with each other, with satellites and with large planets. As a result of the collision of asteroids, smaller celestial bodies are formed - meteorites. When colliding with a planet or satellite, asteroids leave traces in the form of huge multi-kilometer craters.

The surface of all asteroids, without exception, is very cold, since they themselves are like large stones and do not form heat, but are at a considerable distance from the sun. Even if the asteroid is heated by the Sun, it quickly gives off heat.

Astronomers have two of the most popular hypotheses regarding the origin of asteroids. According to one of them, they are fragments of once-existing planets that were destroyed as a result of a collision or explosion. According to another version, asteroids were formed from the remnants of the substance from which the planets of the solar system were formed.

meteorites- small fragments of celestial bodies, consisting mainly of stone and iron, falling to the surface of the Earth from interplanetary space. For astronomers, meteorites are a real treasure: it is rarely possible to carefully study a piece of space in the laboratory. Most experts consider meteorites to be fragments of asteroids that are formed during the collision of space bodies.

4. THEORY OF STARS

A star is a massive gas ball that emits light and is held by its own gravity and internal pressure, in the depths of which thermonuclear fusion reactions take place (or have taken place before).

The main characteristics of the stars:

Luminosity

Luminosity is determined if the apparent magnitude and distance to the star are known. If astronomy has quite reliable methods for determining the apparent magnitude, then it is not so easy to determine the distance to the stars. For relatively close stars, the distance is determined by the trigonometric method known since the beginning of the last century, which consists in measuring negligible angular displacements of stars when they are observed with different points Earth orbit, that is, at different times of the year. This method has a fairly high accuracy and is quite reliable. However, for most other more distant stars, it is no longer suitable: too small shifts in the positions of stars must be measured - less than one hundredth of a second of arc. Other methods come to the rescue, much less accurate, but, nevertheless, quite reliable. In a number of cases, the absolute magnitude of stars can also be determined directly, without measuring the distance to them, from certain observable features of their radiation.

Stars vary greatly in their luminosity. There are white and blue supergiant stars (there are, however, relatively few of them), the luminosities of which exceed the luminosity of the Sun by tens and even hundreds of thousands of times. But most of the stars are "dwarfs", the luminosity of which is much less than the sun, often thousands of times. A characteristic of luminosity is the so-called "absolute value" of a star. The apparent stellar magnitude depends, on the one hand, on its luminosity and color, on the other hand, on the distance to it. High luminosity stars have negative absolute magnitudes, eg -4, -6. Low luminosity stars are characterized by large positive values, such as +8, +10.

Chemical composition of stars

The chemical composition of the outer layers of the star, from where their radiation "directly" comes to us, is characterized by the complete predominance of hydrogen. In second place is helium, and the abundance of other elements is relatively small. For every 10,000 hydrogen atoms, there are about a thousand helium atoms, about ten oxygen atoms, slightly fewer carbon and nitrogen atoms, and just one iron atom. The abundance of other elements is absolutely negligible.

It can be said that the outer layers of stars are giant hydrogen-helium plasmas with a small admixture of heavier elements.

Although the chemical composition of the stars is the same to a first approximation, there are still stars that show certain features in this respect. For example, there is a star with an anomalously high carbon content, or there are objects with an anomalously high content of rare earths. If the vast majority of stars have an abundance of lithium is completely negligible (approximately 10 11 of hydrogen), then occasionally there are "unique" ones where this rare element is quite abundant.

Spectra of stars

Exceptionally rich information is provided by the study of the spectra of stars. The so-called Harvard spectral classification has now been adopted. It has ten classes, denoted in Latin letters: O, B, A, F, G, K, M. The existing system for classifying stellar spectra is so accurate that it allows you to determine the spectrum with an accuracy of one tenth of a class. For example, part of the sequence of stellar spectra between classes B and A is designated as B0, B1 ... B9, A0, and so on. The spectrum of stars in the first approximation is similar to the spectrum of a radiating "black" body with a certain temperature T. These temperatures smoothly change from 40-50 thousand kelvins for stars of the spectral class O to 3000 kelvins for stars of the spectral class M. In accordance with this, the main part of the radiation of stars spectral classes O and B fall on the ultraviolet part of the spectrum, inaccessible to observation from the earth's surface.

Another characteristic feature of stellar spectra is the presence of a huge number of absorption lines belonging to various elements. A fine analysis of these lines made it possible to obtain particularly valuable information about the nature of the outer layers of stars. The differences in the spectra are primarily explained by the difference in temperatures of the outer layers of the star. For this reason, the state of ionization and excitation of different elements in the outer layers of stars differ sharply, which leads to strong differences in the spectra.

Temperature

Temperature determines the color of a star and its spectrum. So, for example, if the temperature of the surface of the layers of stars is 3-4 thousand. K., then its color is reddish, 6-7 thousand K. - yellowish. Very hot stars with temperatures above 10-12 thousand K. have a white or bluish color. In astronomy, there are quite objective methods for measuring the color of stars. The latter is determined by the so-called "color index", equal to the difference between the photographic and visual values. Each value of the color index corresponds to a certain type of spectrum.

The spectra of cool red stars are characterized by absorption lines of neutral metal atoms and bands of some of the simplest compounds (for example, CN, SP, H20, etc.). As the surface temperature increases, molecular bands disappear in the spectra of stars, many lines of neutral atoms, as well as lines of neutral helium, weaken. The very form of the spectrum changes radically. For example, in hot stars with surface layer temperatures exceeding 20 thousand K, predominantly lines of neutral and ionized helium are observed, and the continuous spectrum is very intense in the ultraviolet. Stars with a surface layer temperature of about 10 thousand K have the most intense hydrogen lines, while stars with a temperature of about 6 thousand K have ionized calcium lines located on the border of the visible and ultraviolet parts of the spectrum.

mass of stars

Astronomy did not have and does not currently have a method of direct and independent determination of the mass (that is, not part of multiple systems) of an isolated star. And this is a very serious shortcoming of our science of the universe. If such a method existed, the progress of our knowledge would be much more rapid. The masses of stars vary within relatively narrow limits. There are very few stars whose masses are 10 times greater or less than the sun's. In such a situation, astronomers tacitly accept that stars with the same luminosity and color have the same masses. They are defined only for binary systems. The statement that a single star with the same luminosity and color has the same mass as its "sister", which is part of a binary system, should always be taken with some caution.

It is believed that objects with masses less than 0.02 M are no longer stars. They are devoid of internal sources of energy, and their luminosity is close to zero. Usually these objects are classified as planets. The largest directly measured masses do not exceed 60 M.

STAR CLASSIFICATION

Classifications of stars began to be built immediately after they began to receive their spectra. At the beginning of the 20th century, Hertzsprung and Russell plotted various stars on a diagram, and it turned out that most of them were grouped along a narrow curve. Hertzsprung diagram--shows the relationship between absolute magnitude, luminosity, spectral type, and surface temperature of a star. The stars in this diagram are not arranged randomly, but form well-defined areas.

The diagram makes it possible to find the absolute value by the spectral class. especially for spectral classes O-F. For later classes, this is complicated by the need to make a choice between a giant and a dwarf. However, certain differences in the intensity of some lines allow us to confidently make this choice.

About 90% of the stars are on the main sequence. Their luminosity is due to thermonuclear reactions of the conversion of hydrogen into helium. There are also several branches of evolved stars - giants, in which helium and heavier elements are burned. At the bottom left of the diagram are fully evolved white dwarfs.

TYPES OF STARS

Giants-- a type of star with a much larger radius and high luminosity than main sequence stars that have the same surface temperature. Usually giant stars have radii from 10 to 100 solar radii and luminosities from 10 to 1000 solar luminosities. Stars with a luminosity greater than that of giants are called supergiants and hypergiants. Hot and bright main sequence stars can also be classified as white giants. In addition, due to their large radius and high luminosity, giants lie above the main sequence.

Dwarfs-type of stars of small sizes from 1 to 0.01 radius. of the Sun and low luminosities from 1 to 10-4 of the luminosity of the Sun with a mass of 1 to 0.1 solar masses.

· white dwarf- evolved stars with a mass not exceeding 1.4 solar masses, deprived of their own sources of thermonuclear energy. The diameter of such stars can be hundreds of times smaller than the sun, and therefore the density can be 1,000,000 times that of water.

· red dwarf-- a small and relatively cool main sequence star, having a spectral type M or upper K. They are quite different from other stars. The diameter and mass of red dwarfs does not exceed a third of the solar mass (the lower mass limit is 0.08 solar, followed by brown dwarfs).

· brown dwarf- substellar objects with masses in the range of 5--75 Jupiter masses (and a diameter approximately equal to the diameter of Jupiter), in the depths of which, unlike main sequence stars, there is no thermonuclear fusion reaction with the conversion of hydrogen into helium.

· Subbrown dwarfs or brown subdwarfs are cold formations below the mass limit of brown dwarfs. They are generally considered to be planets.

· black dwarf are white dwarfs that have cooled down and therefore do not radiate in the visible range. Represents the final stage in the evolution of white dwarfs. The masses of black dwarfs, like the masses of white dwarfs, are limited from above by 1.4 solar masses.

neutron star- stellar formations with masses on the order of 1.5 solar masses and sizes noticeably smaller than white dwarfs, on the order of 10-20 km in diameter. The density of such stars can reach 1,000,000,000,000 of the densities of water. And the magnetic field is as many times greater than the Earth's magnetic field. Such stars consist mainly of neutrons tightly compressed by gravitational forces. Often these stars are pulsars.

New star Stars that suddenly increase in luminosity by a factor of 10,000. A nova is a binary system consisting of a white dwarf and a main sequence companion star. In such systems, gas from the star gradually flows into the white dwarf and periodically explodes there, causing a burst of luminosity.

Supernova is a star ending its evolution in a catastrophic explosive process. The flare in this case can be several orders of magnitude larger than in the case new star. Such a powerful explosion is a consequence of the processes taking place in the star at the last stage of evolution.

double star are two gravitationally bound stars revolving around a common center of mass. Sometimes there are systems of three or more stars, in such a general case the system is called a multiple star. In cases where such a star system is not too far removed from the Earth, individual stars can be distinguished through a telescope. If the distance is significant, then it is possible to understand that a double star is possible for astronomers only by indirect signs - fluctuations in brightness caused by periodic eclipses of one star by another and some others.

Pulsars- These are neutron stars, in which the magnetic field is inclined to the axis of rotation and, rotating, they cause modulation of the radiation that comes to Earth.

The first pulsar was discovered at the radio telescope of the Mullard Radio Astronomy Observatory. University of Cambridge. The discovery was made by graduate student Jocelyn Bell in June 1967 at a wavelength of 3.5 m, i.e. 85.7 MHz. This pulsar is called PSR J1921+2153. Observations of the pulsar were kept secret for several months, and then he received the name LGM-1, which means “little green men”. The reason for this was the radio pulses that reached the Earth with a uniform periodicity, and therefore it was assumed that these radio pulses were of artificial origin.

Jocelyn Bell was in Hewish's group, they found 3 more sources of similar signals, after that no one doubted that the signals were not of artificial origin. By the end of 1968, 58 pulsars had already been discovered. And in 2008, 1790 radio pulsars were already known. The closest pulsar to our solar system is 390 light-years away.

Quasars are sparkling objects that radiate the most significant amount of energy found in the universe. Being at a colossal distance from the Earth, they demonstrate greater brightness than cosmic bodies located 1000 times closer. According to the modern definition, a quasar is an active galactic nucleus, where processes take place that release a huge mass of energy. The term itself means "star-like radio source". The first quasar was noticed by the American astronomers A. Sandage and T. Matthews, who were observing the stars at the California observatory. In 1963, M. Schmidt, using a reflector telescope that collects electromagnetic radiation at one point, discovered a red deviation in the spectrum of the observed object, which determines that its source is moving away from our system. Subsequent studies have shown that the celestial body, recorded as 3C 273, is at a distance of 3 billion light years. years and moves away at a tremendous speed - 240,000 km / s. Moscow scientists Sharov and Efremov studied the available early photographs of the object and found that it repeatedly changed its brightness. The irregular change in brightness intensity suggests a small source size.

5. SOURCES OF STAR ENERGY

For a hundred years after the formulation of the law of conservation of energy by R. Mayer in 1842, many hypotheses were expressed about the nature of the energy sources of stars, in particular, a hypothesis was proposed about the fallout of meteoroids onto a star, the radioactive decay of elements, and the annihilation of protons and electrons. Only gravitational contraction and thermonuclear fusion are of real importance.

Thermonuclear fusion in the interior of stars

By 1939, it was established that the source of stellar energy is thermonuclear fusion occurring in the interior of stars. Most stars radiate because, in their interiors, four protons combine through a series of intermediate steps into a single alpha particle. This transformation can proceed in two main ways, called proton-proton or p-p-cycle and carbon-nitrogen or CN-cycle. In low-mass stars, energy release is mainly provided by the first cycle, in heavy stars - by the second. The supply of nuclear energy in a star is finite and is constantly spent on radiation. The process of thermonuclear fusion, which releases energy and changes the composition of the star's matter, in combination with gravity, which tends to compress the star and also releases energy, and radiation from the surface, which carries away the released energy, are the main driving forces of stellar evolution.

Hans Albrecht Bethe is an American astrophysicist who won the Nobel Prize in Physics in 1967. The main works are devoted nuclear physics and astrophysics. It was he who discovered the proton-proton cycle of thermonuclear reactions (1938) and proposed a six-stage carbon-nitrogen cycle, which makes it possible to explain the process of thermonuclear reactions in massive stars, for which he received Nobel Prize in physics for "contributions to the theory of nuclear reactions, especially for discoveries relating to the energy sources of stars."

Gravitational contraction

Gravitational compression is an internal process of a star due to which its internal energy is released.

Let at some point in time, due to the cooling of the star, the temperature in its center will decrease somewhat. The pressure in the center will also decrease, and will no longer compensate for the weight of the overlying layers. The forces of gravity will begin to compress the star. In this case, the potential energy of the system will decrease (since the potential energy is negative, its modulus will increase), while the internal energy, and hence the temperature inside the star, will increase. But only half of the released energy will be spent on raising the temperature. potential energy, the other half will go to maintain the radiation of the star.

6. EVOLUTION OF STARS

Stellar evolution in astronomy is the sequence of changes that a star undergoes during its life, that is, over millions or billions of years, while it radiates light and heat. During such colossal periods of time, the changes are quite significant.

The main phases in the evolution of a star are its birth (star formation), a long period of (usually stable) existence of a star as complete system, which is in hydrodynamic and thermal equilibrium, and, finally, the period of its "death", i.e. an irreversible imbalance that leads to the destruction of a star or to its catastrophic compression. The evolution of a star depends on its mass and initial chemical composition, which, in turn, depends on the time of formation of the star and its position in the Galaxy at the moment of formation. The greater the mass of a star, the faster its evolution and the shorter its "life".

A star begins its life as a cold rarefied cloud of interstellar gas that contracts under its own gravity and gradually takes on the shape of a ball. When compressed, the gravitational energy is converted into heat, and the temperature of the object increases. When the temperature in the center reaches 15-20 million K, thermonuclear reactions begin and the compression stops. The object becomes a full-fledged star.

After a certain time - from a million to tens of billions of years (depending on the initial mass) - the star depletes the hydrogen resources of the core. In large and hot stars, this happens much faster than in small and colder ones. The depletion of the supply of hydrogen leads to the cessation of thermonuclear reactions.

Without the pressure generated by these reactions to balance the internal gravity in the body of the star, the star begins to contract again, as it did earlier in the process of its formation. The temperature and pressure increase again, but, unlike the protostar stage, to much more high level. The collapse continues until, at a temperature of approximately 100 million K, thermonuclear reactions involving helium begin.

The thermonuclear "burning" of matter resumed at a new level causes a monstrous expansion of the star. The star "swells up", becoming very "loose", and its size increases by about 100 times. So the star becomes a red giant, and the helium burning phase lasts about several million years. Almost all red giants are variable stars.

After the termination of thermonuclear reactions in their core, they, gradually cooling down, will continue to weakly radiate in the infrared and microwave ranges of the electromagnetic spectrum.

SUN

The sun is the only star in the solar system, all the planets of the system, as well as their satellites and other objects, move around it, up to cosmic dust.

Characteristics of the Sun

Mass of the Sun: 2,1030 kg (332,946 Earth masses)

Diameter: 1,392,000 km

Radius: 696,000 km

· Average density: 1 400 kg/m3

Axial tilt: 7.25° (relative to the plane of the ecliptic)

Surface temperature: 5,780 K

Temperature at the center of the Sun: 15 million degrees

Spectral class: G2 V

Average distance from Earth: 150 million km

Age: about 5 billion years

Rotation period: 25.380 days

Luminosity: 3.86 1026W

Apparent magnitude: 26.75m

The structure of the sun

According to the spectral classification, the star belongs to the “yellow dwarf” type, according to rough calculations, its age is just over 4.5 billion years, it is in the middle of its life cycle. The sun, which consists of 92% hydrogen and 7% helium, has a very complex structure. At its center is a core with a radius of approximately 150,000-175,000 km, which is up to 25% of the total radius of the star; at its center, the temperature approaches 14,000,000 K. The core rotates around its axis at high speed, and this speed significantly exceeds indicators of the outer shells of the star. Here, the reaction of the formation of helium from four protons takes place, as a result of which a large amount of energy is obtained, passing through all layers and radiating from the photosphere in the form of kinetic energy and light. Above the core is a radiative transport zone, where temperatures are in the range of 2-7 million K. Then follows a convective zone about 200,000 km thick, where there is no longer reradiation for energy transfer, but plasma mixing. At the surface of the layer, the temperature is approximately 5800 K. The atmosphere of the Sun consists of the photosphere, which forms the visible surface of the star, the chromosphere about 2000 km thick and the corona, the last outer solar shell, the temperature of which is in the range of 1,000,000-20,000,000 K. From the outer part corona is the release of ionized particles, called the solar wind.

Magnetic fields play an important role in the occurrence of phenomena occurring on the Sun. The matter on the Sun is everywhere a magnetized plasma. Sometimes tensions in certain areas magnetic field increases rapidly and strongly. This process is accompanied by the appearance of a whole complex of phenomena of solar activity in different layers of the solar atmosphere. These include faculae and spots in the photosphere, flocculi in the chromosphere, prominences in the corona. The most remarkable phenomenon, covering all layers of the solar atmosphere and originating in the chromosphere, are solar flares.

In the course of observations, scientists found that the Sun is a powerful source of radio emission. Radio waves penetrate into interplanetary space, which are emitted by the chromosphere (centimeter waves) and the corona (decimeter and meter waves).

The radio emission of the Sun has two components - constant and variable (bursts, "noise storms"). During strong solar flares, the radio emission from the Sun increases thousands and even millions of times compared to the radio emission from the quiet Sun. This radio emission has a non-thermal nature.

X-rays come mainly from the upper layers of the chromosphere and the corona. The radiation is especially strong during the years of maximum solar activity.

The sun radiates not only light, heat and all other types of electromagnetic radiation. It is also the source of a constant stream of particles -- corpuscles. Neutrinos, electrons, protons, alpha particles, and heavier atomic nuclei all together constitute the corpuscular radiation of the Sun. A significant part of this radiation is a more or less continuous outflow of plasma - the solar wind, which is a continuation of the outer layers of the solar atmosphere - the solar corona. Against the background of this constantly blowing plasma wind, individual regions on the Sun are sources of more directed, enhanced, so-called corpuscular flows. Most likely, they are associated with special regions of the solar corona - coronary holes, and also, possibly, with long-lived active regions on the Sun. Finally, the most powerful short-term particle fluxes, mainly electrons and protons, are associated with solar flares. As a result, the most powerful flashes particles can acquire velocities that are a significant fraction of the speed of light. Particles with such high energies are called solar cosmic rays.

Solar corpuscular radiation has strong influence to the Earth, and above all to the upper layers of its atmosphere and magnetic field, causing many interesting geophysical phenomena.

The evolution of the sun

It is believed that the Sun was formed about 4.5 billion years ago, when the rapid compression under the action of gravitational forces of a cloud of molecular hydrogen led to the formation of a star of the first type of stellar population of the T Taurus type in our region of the Galaxy.

A star of the same mass as the Sun should exist on the main sequence for a total of about 10 billion years. Thus, now the Sun is approximately in the middle of its life cycle. At the present stage, thermonuclear reactions of the conversion of hydrogen into helium are taking place in the solar core. Every second in the core of the Sun, about 4 million tons of matter is converted into radiant energy, resulting in the generation of solar radiation and a stream of solar neutrinos.

When the Sun reaches an age of about 7.5 - 8 billion years (that is, after 4-5 billion years), the star will turn into a red giant, its outer shells will expand and reach the Earth's orbit, possibly pushing the planet more far distance. Under the influence of high temperatures, life in today's sense will become simply impossible. The Sun will spend the final cycle of its life in the state of a white dwarf.

CONCLUSION

From this work, the following conclusions can be drawn:

The main elements of the structure of the universe: galaxies, stars, planets

Galaxies - systems of billions of stars revolving around the center of the galaxy and connected by mutual gravity and common origin,

Planets are bodies that do not emit energy, with a complex internal structure.

The most common celestial body in the observable universe are stars.

According to modern concepts, a star is a gas-plasma object in which thermonuclear fusion occurs at temperatures above 10 million degrees K.

· The main methods of studying the visible Universe are telescopes and radio telescopes, spectral reading and radio waves;

The main concepts describing stars are:

A magnitude that characterizes not the size of a star, but its brilliance, that is, the illumination that a star creates on Earth;

...

Explanation of the glow of stars

Stars are inherently gas balls, therefore, they emit light in the course of their existence and the chemical processes taking place in them. Unlike the moon, which simply reflects the light of the sun, stars, like our sun, glow on their own. If we talk about our sun, it is a medium in size, as well as in age, a star. As a rule, those stars that visually appear larger in the sky are closer, those that are barely visible are further away. There are millions more that are not visible to the naked eye at all. People got acquainted with them when the first telescope was invented.

The star, although it is not alive, has its own life cycle, therefore, at its different stages, it has a different glow. When her life path comes to an end, it gradually turns into a red dwarf. In this case, its light, respectively, is reddish, as if impulses are possible, the light seems to flash, like the glow of an incandescent lamp during sudden voltage drops in the network. Certain parts of it are now covered with a crust, then explode again with renewed vigor, visually forming such flashes.

Another reason for the difference in the cross section of stars lies in their spectrality. It's like the length and frequency of the light rays they emit. It depends on the chemical composition of the star, as well as its size.

All stars are also different in size. But what is meant here is not how they look to us when looking at the sky in the evening or at night, but their real sizes, which are calculated by astronomers with varying degrees of accuracy.

I must say that the stars shine not only at night, but also during the day. It's just that the sun in the daytime illuminates the atmosphere, we see it, consisting of many layers of clouds. At night, the sun illuminates the other side of the earth, and where it is dark, the atmosphere becomes transparent. This is how we see what surrounds our planet - the stars, its satellite, the Moon, sometimes even meteorites, comets, even another planet in the solar system - Venus. It seems to be a big star, but its glow, like the moon, is due to the fact that it reflects sunlight. Venus is seen mostly in the early evening or at dawn.

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If the baby has grown to the age of "why" and bombards you with questions about why the stars shine, how far to the sun and what a comet is, it's time to introduce him to the basics of astronomy, help him understand the structure of the world, support research interest.

"If there was only one place on Earth from where one could see the stars, then people would flock there in droves to contemplate the wonders of the sky and admire them." (Seneca, 1st century AD) It is hard to disagree that in this sense, little has changed on earth for thousands of years.

The bottomlessness and immensity of the starry sky still inexplicably attracts the views of people,

fascinates, hypnotizes, fills the soul with quiet and gentle joy, a feeling of unity with the entire universe. And if even an adult imagination sometimes draws amazing pictures, then what can we say about our children, dreamers and inventors who live in fairy-tale worlds, fly in a dream and dream of space travel and meetings with an alien mind...

Where to begin?

Acquaintance with astronomy should not begin with the "big bang theory". It is sometimes difficult even for an adult to realize the infinity of the Universe, and even more so for a baby, for whom even his own home is still akin to the Universe. It is not necessary to buy a telescope right away. This is a unit for "advanced" young astronomers. In addition, many interesting observations can be made with the help of binoculars. And it’s better to start with buying a good book on astronomy for kids, with a visit to the children’s program at the planetarium, the space museum, and, of course, with interesting and intelligible stories from mom and dad about planets and stars.

Tell your child that our Earth is a huge ball on which there was a place for rivers, mountains, forests, deserts, and, of course, all of us, its inhabitants. Our Earth and everything that surrounds it is called the Universe or space. Space is very large, and no matter how much we fly in a rocket, we will never be able to get to its edge. In addition to our Earth, there are other planets, as well as stars. Stars are huge luminous fireballs. The sun is also a star. It is located close to the Earth, and therefore we see its light and feel heat. There are stars many times larger and hotter than the Sun, but they shine so far from the Earth that they seem to us just small dots in the night sky. Often kids ask why the stars are not visible during the day. Compare with your child the light of a flashlight during the day and in the evening in the dark. In the daytime, in bright light, the beam of the flashlight is almost invisible, but it shines brightly in the evening. The light of the stars is like the light of a lantern: during the day it is outshone by the sun. Therefore, the stars can only be seen at night.

In addition to our Earth, 8 more planets circle the Sun, many small asteroids and comets. All these celestial bodies form the solar system, the center of which is the sun. Each planet has its own path, which is called an orbit. To remember the names and order of the planets, the baby will help "Astronomical rhyme" by A. Usachev:

An astrologer lived on the moon, He counted the planets. Mercury - one, Venus - two, three - Earth, four - Mars. Five - Jupiter, six - Saturn, Seven - Uranus, eighth - Neptune, Nine - farthest - Pluto. Who does not see - get out.

Tell your child that all the planets in the solar system vary greatly in size. If you imagine that the largest of them, Jupiter, is the size of a large watermelon, then the smallest planet, Pluto, will look like a pea. All planets in the solar system, except for Mercury and Venus, have satellites. Our Earth also has it...

mysterious moon

Even a one and a half year old toddler is already enthusiastically looking at the moon in the sky. And for a grown-up kid, this satellite of the Earth can become an interesting object of study. After all, the Moon is so different and is constantly changing from a barely noticeable "sickle" to a round bright beauty. Tell the kid, and even better, demonstrate with the help of a globe, a small ball (this will be the Moon) and a flashlight (this will be the Sun), how the Moon revolves around the Earth and how it is illuminated by the Sun.

In order to better understand and remember the phases of the moon, start an observation diary with your baby, where every day you will sketch the moon as it is visible in the sky. If on some days clouds interfere with your observations, it does not matter. Still, such a diary will be an excellent visual aid. And to determine whether the moon is waxing or waning in front of you is very simple. If her sickle looks like the letter "C" - she is old, if the letter "R" without a stick - growing.

Of course, the baby will be interested to know what is on the moon. Tell him that the surface of the moon is covered with craters caused by asteroid impacts. If you look at the Moon with binoculars (it is better to install it on a photo tripod), then you can notice the unevenness of its relief and even craters. The moon has no atmosphere, so it is not protected from asteroids. But the Earth is protected. If a stone shard enters its atmosphere, it immediately burns up. Although sometimes asteroids are so fast that they still have time to fly to the surface of the Earth. Such asteroids are called meteorites.

Star riddles

While relaxing with your grandmother in the village or in the country, devote a few evenings to stargazing. There is nothing to worry about if the child breaks the usual routine a little and goes to bed later. But how many unforgettable minutes he will spend with his mom or dad under a huge starry sky, peering into the shimmering mysterious points. August is the best month for such observations. The evenings are quite dark, the air is transparent and it seems that you can reach the sky with your hands. In August, it is easy to see an interesting phenomenon, which is called a "shooting star". Of course, in fact, this is not a star at all, but a burning meteor. But still very beautiful. Our distant ancestors looked at the sky in the same way, guessing various animals, objects, people, mythological heroes in the clusters of stars. Many constellations bear their names from time immemorial. Teach your child to find a particular constellation in the sky. Such an activity awakens imagination in the best possible way and develops abstract thinking. If you yourself are not very good at navigating the constellations, it does not matter. Almost all children's books on astronomy have a map of the starry sky and descriptions of the constellations. In total, 88 constellations have been identified on the celestial sphere, 12 of which are zodiacal. The stars in the constellations are designated by letters of the Latin alphabet, and the brightest ones have their own names (for example, the star Altair in the constellation Eagle). To make it easier for a child to see this or that constellation in the sky, it makes sense to first carefully examine it in the picture, and then draw or lay it out of cardboard stars. You can make constellations on the ceiling using special luminous star stickers. Once having found a constellation in the sky, the child will never forget it.

At different peoples the same constellation could be called differently. It all depended on what their fantasy suggested to people. So, the well-known Ursa Major was depicted both as a ladle and as a horse on a leash. Amazing legends are associated with many constellations. It would be great if mom or dad would read some of them in advance, and then retell them to the baby, peering into the luminous dots with him and trying to see the legendary creatures. The ancient Greeks, for example, had such a legend about the constellations Ursa Major and Ursa Minor. The almighty god Zeus fell in love with the beautiful nymph Callisto. The wife of Zeus Hera, having learned about this, was terribly angry and turned Callisto and her friend into a she-bear. The son of Callisto Araks met two bears during a hunt and wanted to kill them. But Zeus prevented this by throwing Callisto and her friend into the sky and turning them into bright constellations. And, throwing, Zeus held the bears by the tails. Here are the tails and have become long. And here is another beautiful legend about several constellations at once. A long time ago, Cepheus lived in Ethiopia. His wife was the beautiful Cassiopeia. They had a daughter, the beautiful princess Andromeda. She grew up and became the most beautiful girl in Ethiopia. Cassiopeia was so proud of her daughter's beauty that she began to compare her with goddesses. The gods were angry and sent a terrible misfortune to Ethiopia. Every day a monstrous whale swam out of the sea, and the most beautiful girl was given to him to be eaten. The turn of the beautiful Andromeda has come. No matter how Cepheus begged the gods to spare his daughter, the gods remained adamant. Andromeda was chained to a rock by the sea. But at this time, the hero Perseus flew past in winged sandals. He had just accomplished the feat of killing the dreaded Medusa Gorgon. Instead of hair, snakes moved on her head, and one look from her turned all living things into stone. Perseus saw a poor girl and a terrible monster, pulled out the severed head of Medusa from the bag and showed it to the whale. The whale was petrified, and Perseus freed Andromeda. Delighted, Cepheus gave Andromeda as his wife to Perseus. And the gods liked this story so much that they turned all its heroes into bright stars and placed them in the sky. Since then, you can find there: Cassiopeia, and Cepheus, and Perseus, and Andromeda. And the whale became an island off the coast of Ethiopia.

It is not difficult to find the Milky Way in the sky. It is clearly visible to the naked eye. Tell your child that the Milky Way (namely, this is the name of our galaxy) is a large cluster of stars that looks like a luminous strip of white dots in the sky and resembles a milk path. The ancient Romans attributed the origin of the Milky Way to the sky goddess Juno. When she was breastfeeding Hercules, a few drops fell and, turning into stars, formed the Milky Way in the sky ...

Choosing a telescope

If a child is seriously interested in astronomy, it makes sense to purchase a telescope for him. True, a good telescope is not cheap. But even inexpensive models of children's telescopes will allow a young astronomer to observe many celestial objects and make his first astronomical discoveries. Mom and dad should remember that even the simplest telescope is a rather complicated thing for a preschooler. Therefore, firstly, the child can not do without your active help. And, secondly, the simpler the telescope, the easier it will be for the baby to manage it. If in the future the child becomes seriously interested in astronomy, it will be possible to purchase a more powerful telescope.

So, what is a telescope and what to look for when choosing one? The principle of operation of the telescope is not based on the magnification of the object, as many people think. It is more correct to say that the telescope does not enlarge, but brings the object closer. The main task of the telescope is to create an image of a distant object close to the observer and allow details to be distinguished; not accessible to the naked eye; The second task is to collect as much light as possible from a distant object and transmit it to our eye. So, the larger the lens, the more light the telescope collects and the better the detail of the objects in question will be.

All telescopes are divided into three optical classes. Refractors(refracting telescopes) a large objective lens is used as a light-collecting element. IN reflex(reflecting) telescopes, concave mirrors play the role of an objective. The most common and easiest to manufacture reflector is made according to the Newton optical scheme (named after Isaac Newton, who first put it into practice). Often these telescopes are called "Newton". Mirror lens Telescopes use both lenses and mirrors at the same time. Due to this, they allow you to achieve excellent image quality with high resolution. Most children's telescopes that you will find in stores are refractors.

An important parameter to pay attention to is lens diameter(aperture). It determines the light gathering power of the telescope and the range of possible magnifications. It is measured in millimeters, centimeters or inches (for example, 4.5 inches is 114 mm). The larger the diameter of the lens, the more "weak" stars can be seen through a telescope. The second important feature is focal length. The aperture ratio of the telescope depends on it (as in amateur astronomy they call the ratio of the diameter of the lens to its focal length). Pay attention also to eyepiece. If the main optic (objective lens, mirror or system of lenses and mirrors) serves to form an image, then the purpose of the eyepiece is to magnify this image. Eyepieces come in different diameters and focal lengths. Changing the eyepiece will also change the magnification of the telescope. To calculate the magnification, you need to divide the focal length of the telescope objective (say, 900 mm) by the focal length of the eyepiece (for example, 20 mm). We get a magnification of 45 times. This is quite enough for a novice young astronomer to consider the Moon, star clusters and a lot of other interesting things. The telescope kit may include a Barlow lens. It is installed in front of the eyepiece, which increases the magnification of the telescope. In simple telescopes, the double barlow lens. It allows you to double the magnification of the telescope. In our case, the increase will be 90 times.

The telescopes come with many useful accessories. They can be included with the telescope or ordered separately. For example, most telescopes are equipped with viewfinders. This is a small telescope with a low magnification and a large field of view, which makes it easy to find the desired objects of observation. The viewfinder and telescope are directed parallel to each other. First, the object is determined in the viewfinder, and only then in the field of the main telescope. Almost all refractors are equipped with diagonal mirror or prism. This device facilitates observations if the object is directly above the astronomer's head. If, in addition to celestial objects, you are going to observe terrestrial objects, you cannot do without rectifying prism. The fact is that all telescopes receive an image turned upside down and mirrored. When observing celestial bodies, this does not really matter. But to see earthly objects is still better in the correct position.

Any telescope has a mount - a mechanical device for attaching the telescope to a tripod and aiming at an object. It can be azimuth or equatorial. The azimuth mount allows you to move the telescope in the horizontal direction (left-right) and vertical (up-down). This mount is suitable for observing both terrestrial and celestial objects and is most often installed in telescopes for novice astronomers. Another type of mount, equatorial, is arranged differently. During long-term astronomical observations, due to the rotation of the earth, objects shift. Thanks to a special design, the equatorial mount allows the telescope to follow the curved path of the star across the sky. Sometimes such a telescope is equipped with a special motor that controls the movement automatically. A telescope on an equatorial mount is more suitable for long-term astronomical observations and photography. And finally, this whole device is mounted on tripod. Most often it is metal, less often - wooden. It is better if the legs of the tripod are not fixed, but retractable.

How to work

Seeing something through a telescope is not so simple task for a beginner, as it may seem at first glance. You need to know what to look for. This time. You need to know where to look. This is two. And, of course, know how to search. It's three. Let's start from the end and try to figure out the basic rules for handling a telescope. Don't worry about the fact that you yourself are not very good at astronomy (or even not at all). Finding the right literature is not a problem. But how interesting it will be for both you and the child to discover this difficult, but such an exciting science together.

So, before you start searching for any object in the sky, you need to set up a viewfinder with a telescope. This procedure requires some skill. Do it better during the day. Select a fixed, easily recognizable ground object at a distance of 500 meters to one kilometer. Point the telescope at it so that the object is in the center of the eyepiece. Fix the telescope so that it is stationary. Now look through the viewfinder. If the selected subject is not visible, loosen the viewfinder adjustment bolt and rotate the viewfinder itself until the subject appears in the field of view. Then, use the adjustment screws (viewfinder fine adjustment screws) to ensure that the object is exactly in the center of the eyepiece. Now look through the telescope again. If the object is still in the center - everything is in order. The telescope is ready to go. If not, repeat the setting.

As you know, it is better to look through a telescope in a dark tower somewhere high in the mountains. Of course, we are unlikely to go to the mountains. But, undoubtedly, it is better to watch the stars outside the city (for example, in the country) than from the window of a city apartment. There is too much extra light and heat waves in the city, which will degrade the image. The farther away from urban illumination you make observations, the more celestial objects you will be able to see. It is clear that the sky should be as clear as possible.

First find the subject in the viewfinder. Then adjust the focus of the telescope - turn the focus screw until the image is clear. If you have multiple eyepieces, start with the lowest magnification. Due to the very fine tuning of the telescope, you need to look into it carefully, without making sudden movements and with bated breath. Otherwise, the setting can easily go astray. Teach your child right away. By the way, such observations will train endurance, and for overly active smart people they will become a kind of psychotherapeutic procedure. It is difficult to find a better soothing remedy than watching the endless starry sky.

Depending on the model of the telescope, several hundred different celestial objects can be viewed through it. These are planets, stars, galaxies, asteroids, comets.

asteroids(minor planets) are large pieces of rock, sometimes containing metal. Most asteroids orbit the Sun between Mars and Jupiter.

Comets- These are celestial bodies that have a core and a luminous tail. So that the baby can imagine this "tailed wanderer" at least a little, tell her that she looks like a huge snowball mixed with space dust. In a telescope, comets appear as hazy spots, sometimes with a light tail. The tail is always turned away from the Sun.

Moon. Even with the simplest telescope, you can clearly see craters, crevices, mountain ranges and dark seas. It is best to observe the moon not during the full moon, but during one of its phases. At this time, you can see much more details, especially at the border of light and shadow.

planets. In any telescope, you can see all the planets of the Solar System, except for the most distant - Pluto (it is visible only in powerful telescopes). Mercury and Venus, as well as the Moon, have phases when they are visible through a telescope. On Jupiter, you can see dark and light bands (which are belts of clouds) and a giant whirlwind of the Great Red Spot. Due to the planet's rapid rotation appearance constantly changing. Jupiter's four helium moons are clearly visible. On the mysterious red planet Mars, with a good telescope, you can see the white ice caps at the poles. The famous ring of Saturn, which children love to look at in pictures, is also perfectly visible through a telescope. This is an amazing picture. The largest moon of Saturn, Titan, is usually clearly visible. And in more powerful telescopes, you can see the gap in the rings (Cassini gap) and the shadow that the rings cast on the planet. Uranus and Neptune will be visible as small dots, and in more powerful telescopes as disks.

Between the orbits of Mars and Jupiter, many asteroids can be observed. Sometimes comets come across.

star clusters. Throughout our galaxy, there are many star clusters, which are divided into scattered (a significant cluster of stars in some part of the sky) and globular (dense group of stars, shaped like a ball). For example, the Pleiades constellation (seven small stars pressed against each other), clearly visible to the naked eye, turns into a sparkling field of hundreds of stars in the eyepiece of even the simplest telescope.

Nebulae. Scattered throughout our galaxy are clusters of gas. This is what nebulae are. Usually they are illuminated by neighboring stars and are a very beautiful sight.

galaxies. These are huge clusters of billions of stars, separate "islands" of the Universe. The brightest galaxy in the night sky is the Andromeda Galaxy. Without a telescope, it looks like a faint blur. A large elliptical luminous field can be seen through a telescope. And in a more powerful telescope, the structure of the galaxy is visible.

Sun. It is strictly forbidden to look at the Sun through a telescope, unless it is equipped with special solar filters. Explain this to your child first. This will damage the telescope. But this is half the trouble. There is one sad aphorism that you can look at the Sun through a telescope only twice in your life: once with your right eye, the second time with your left. Such experiments can indeed lead to loss of vision. And it is better not to leave the telescope assembled in the daytime, so as not to tempt the little astronomer.

In addition to astronomical observations, most telescopes allow you to observe terrestrial objects, which can also be very interesting. But, much more important, not so much the observations themselves, but the joint passion of the baby and parents, common interests that make the friendship between the child and the adult stronger, fuller and more interesting.

Clear skies and amazing astronomical discoveries!

Stars do not reflect light, as planets and their satellites do, but radiate it. And evenly and constantly. And the blinking visible on Earth is possibly caused by the presence of various microparticles in space, which, falling into the light beam, interrupt it.

The brightest star, from the point of view of earthlings

From the school bench it is known that the Sun is a star. From our planet - and by the standards of the Universe - a little less than average both in size and in brightness. A huge number of stars are larger than the Sun, but they are much smaller.

star gradation

Ancient Greek astronomers began to divide the heavenly bodies by size. The concept of "magnitude" both then and now means the brightness of the glow of a star, and not its physical magnitude.

Stars also differ in the length of their radiation. According to the wave spectrum, and it is really diverse, astronomers can tell about chemical composition body, temperature and even distance.

scientists argue

The controversy on the question “why the stars shine” has been going on for decades. There is still no consensus. It is hard to believe even for nuclear physicists that the reactions taking place in a stellar body can release such a huge amount of energy without stopping.

The problem of what passes in the stars has occupied scientists for a very long time. Astronomers, physicists, chemists have attempted to find out what gives impetus to the eruption of thermal energy, which is accompanied by bright radiation.

Chemists believe that the light from a distant star is the result of an exothermic reaction. It ends with the release of a significant amount of heat. Physicists say that chemical reactions cannot take place in the body of a star. For none of them is capable of going non-stop for billions of years.

The answer to the question "why do stars shine" got a little closer after Mendeleev's discovery of the table of elements. Now chemical reactions have been considered in a completely new way. As a result of the experiments, new radioactive elements were obtained, and the theory of radioactive decay becomes version number one in the endless dispute about the glow of stars.

Modern hypothesis

The light of a distant star did not allow Svante Arrhenius, a Swedish scientist, to “sleep”. At the beginning of the last century, he turned the idea of heat radiation from stars by developing a concept. It consisted of the following. The main source of energy in the body of a star is hydrogen atoms, which are constantly involved in chemical reactions with each other, form helium, which is much heavier than its predecessor. The transformation processes occur due to the pressure of a gas of high density and a temperature that is wild for our understanding (15,000,000̊С).

The hypothesis has pleased many scientists. The conclusion was unequivocal: the stars in the night sky glow because a fusion reaction takes place inside and the energy released during this is more than enough. It also became clear that the combination of hydrogen can go on non-stop for many billions of years in a row.

So why do the stars shine? The energy that is released in the core is transferred to the outer gaseous shell and radiation visible to us occurs. Today, scientists are almost sure that the "road" of the beam from the core to the shell takes more than a hundred thousand years. A beam from a star also travels a long time to the Earth. If the radiation from the Sun reaches the Earth in eight minutes, the brighter stars - Proxima Centauri - in almost five years, then the light of the rest can go for tens and hundreds of years.

One more "why"

Why stars emit light is now clear. Why is it flickering? The glow coming from the star is actually even. This is due to gravity, which pulls the gas expelled by the star back. The twinkling of a star is a kind of error. The human eye sees a star through several layers of air that is in constant motion. The star beam, passing through these layers, seems to flicker.

Since the atmosphere is constantly moving, hot and cold air flows, passing under each other, form vortices. This causes the light beam to bend. also changes. The reason is the uneven concentration of the beam reaching us. The stellar picture itself is also shifting. The reason for this phenomenon is passing in the atmosphere, for example, gusts of wind.

colorful stars

In cloudless weather, the night sky pleases the eye with bright multicolor. A rich orange color in and Arcturus, but Antares and Betelgeuse are pale red. Sirius and Vega are milky white, with a blue tint - Regulus and Spica. The famous giants - Alpha Centauri and Capella - are juicy yellow.

Why do stars shine differently? The color of a star depends on its internal temperature. The coldest ones are red. On their surface, only 4,000 °C. with surface heating up to 30,000 ̊С - are considered the hottest.

Astronauts say that in fact the stars light evenly and brightly, and they wink only at earthlings ...