What is the Milky Way? Milky Way Galaxy: interesting facts.

The cosmos that we are trying to study is a huge and endless space in which there are tens, hundreds, thousands of trillions of stars, united in certain groups. Our Earth does not live on its own. We are part of the solar system, which is a small particle and part of the Milky Way, a larger cosmic formation.

Our Earth, like other planets of the Milky Way, our star called the Sun, like other stars of the Milky Way, move in the Universe in in a certain order and take their assigned places. Let's try to understand in more detail what is the structure of the Milky Way, and what are the main features of our galaxy?

Origin of the Milky Way

Our galaxy has its own history, like other areas of outer space, and is the product of a catastrophe on a universal scale. The main theory of the origin of the Universe that dominates the scientific community today is the Big Bang. A model that perfectly characterizes the Big Bang theory is the chain model. nuclear reaction at the microscopic level. Initially, there was some kind of substance that, for certain reasons, instantly began to move and exploded. There is no need to talk about the conditions that led to the onset of the explosive reaction. This is far from our understanding. Now the Universe, formed 15 billion years ago as a result of a cataclysm, is a huge, endless polygon.

The primary products of the explosion initially consisted of accumulations and clouds of gas. Subsequently, under the influence gravitational forces and others physical processes the formation of larger objects of a universal scale occurred. Everything happened very quickly by cosmic standards, over billions of years. First there was the formation of stars, which formed clusters and later merged into galaxies, the exact number of which is unknown. In terms of its composition, galactic matter is atoms of hydrogen and helium in the company of other elements, which are building material for the formation of stars and other space objects.

It is not possible to say exactly where in the Universe the Milky Way is located, since the exact center of the universe is unknown.

Due to the similarity of the processes that formed the Universe, our galaxy is very similar in structure to many others. By its type, it is a typical spiral galaxy, a type of object that is widespread in the Universe. In terms of its size, the galaxy is in the golden mean - neither small nor huge. Our galaxy has many more smaller stellar neighbors than those of colossal size.

The age of all galaxies that exist in outer space. Our galaxy is almost the same age as the Universe and is 14.5 billion years old. Over this enormous period of time, the structure of the Milky Way has changed several times, and this is still happening today, only imperceptibly, in comparison with the pace of earthly life.

There is a curious story about the name of our galaxy. Scientists believe that the name Milky Way is legendary. This is an attempt to connect the location of the stars in our sky with the ancient Greek myth about the father of the gods Kronos, who devoured his own children. Last child, who faced the same sad fate, turned out to be thin and was given to a nurse to be fattened. During feeding, splashes of milk fell on the sky, thereby creating a milk trail. Subsequently, scientists and astronomers of all times and peoples agreed that our galaxy is indeed very similar to a milk road.

Currently, the Milky Way is in the middle of its development cycle. In other words, the cosmic gas and material to form new stars is running out. The existing stars are still quite young. As in the story with the Sun, which may turn into a Red Giant in 6-7 billion years, our descendants will observe the transformation of other stars and the entire galaxy as a whole into the red sequence.

Our galaxy may cease to exist as a result of another universal cataclysm. Research topics recent years are guided by the upcoming meeting of the Milky Way with our closest neighbor, the Andromeda galaxy, in the distant future. It is likely that the Milky Way will break up into several small galaxies after meeting the Andromeda Galaxy. In any case, this will be the reason for the emergence of new stars and the reorganization of the space closest to us. We can only guess what the fate of the Universe and our galaxy will be in the distant future.

Astrophysical parameters of the Milky Way

In order to imagine what the Milky Way looks like on a cosmic scale, it is enough to look at the Universe itself and compare its individual parts. Our galaxy is part of a subgroup, which in turn is part of the Local Group, a larger formation. Here our cosmic metropolis neighbors the Andromeda and Triangulum galaxies. The trio is surrounded by more than 40 small galaxies. The local group is already part of an even larger formation and is part of the Virgo supercluster. Some argue that these are only rough guesses about where our galaxy is located. The scale of the formations is so enormous that it is almost impossible to imagine it all. Today we know the distance to the nearest neighboring galaxies. Other deep space objects are out of sight. Their existence is only theoretically and mathematically allowed.

The location of the galaxy became known only thanks to approximate calculations that determined the distance to its nearest neighbors. The Milky Way's satellites are dwarf galaxies - the Small and Large Magellanic Clouds. In total, according to scientists, there are up to 14 satellite galaxies that form the escort of the universal chariot called the Milky Way.

As for the visible world, today there is enough information about what our galaxy looks like. The existing model, and with it the map of the Milky Way, is compiled on the basis of mathematical calculations, data obtained as a result of astrophysical observations. Each cosmic body or fragment of the galaxy takes its place. This is just like in the Universe, only on a smaller scale. The astrophysical parameters of our cosmic metropolis are interesting, and they are impressive.

Our galaxy is a barred spiral galaxy, which is designated on star maps by the index SBbc. The diameter of the galactic disk of the Milky Way is about 50-90 thousand light years or 30 thousand parsecs. For comparison, the radius of the Andromeda galaxy is 110 thousand light years on the scale of the Universe. One can only imagine how much larger our neighbor is than the Milky Way. The sizes of the dwarf galaxies closest to the Milky Way are tens of times smaller than those of our galaxy. Magellanic clouds have a diameter of only 7-10 thousand light years. There are about 200-400 billion stars in this huge stellar cycle. These stars are collected in clusters and nebulae. A significant part of it is the arms of the Milky Way, in one of which our solar system is located.

Everything else is dark matter, clouds of cosmic gas and bubbles that fill interstellar space. The closer to the center of the galaxy, the more stars, the more crowded outer space becomes. Our Sun is located in a region of space consisting of smaller space objects located at a considerable distance from each other.

The mass of the Milky Way is 6x1042 kg, which is trillions of times more than the mass of our Sun. Almost all the stars inhabiting our stellar country are located in the plane of one disk, the thickness of which, according to various estimates, is 1000 light years. It is not possible to know the exact mass of our galaxy, since most of the visible spectrum of stars is hidden from us by the arms of the Milky Way. In addition, the mass of dark matter, which occupies vast interstellar spaces, is unknown.

The distance from the Sun to the center of our galaxy is 27 thousand light years. Being on the relative periphery, the Sun rapidly moves around the center of the galaxy, completing a full revolution every 240 million years.

The center of the galaxy has a diameter of 1000 parsecs and consists of a core with an interesting sequence. The center of the core has the shape of a bulge, in which the largest stars and a cluster of hot gases are concentrated. It is this region that releases a huge amount of energy, which in total is greater than that emitted by the billions of stars that make up the galaxy. This part of the core is the most active and brightest part of the galaxy. At the edges of the core there is a bridge, which is the beginning of the arms of our galaxy. Such a bridge arises as a result of the colossal gravitational force caused by the rapid rotation speed of the galaxy itself.

Considering the central part of the galaxy, the following fact appears paradoxical. Scientists for a long time could not understand what was in the center of the Milky Way. It turns out that in the very center of a star country called the Milky Way there is a supermassive black hole, the diameter of which is about 140 km. It is there that most of the energy released by the galactic core goes; it is in this bottomless abyss that stars dissolve and die. The presence of a black hole at the center of the Milky Way indicates that all processes of formation in the Universe must end someday. Matter will turn into antimatter and everything will happen again. How this monster will behave in millions and billions of years, the black abyss is silent, which indicates that the processes of absorption of matter are only gaining strength.

The two main arms of the galaxy extend from the center - the Shield of the Centaur and the Shield of Perseus. These structural formations received their names from the constellations located in the sky. In addition to the main arms, the galaxy is surrounded by 5 more minor arms.

Near and distant future

The arms, born from the core of the Milky Way, unwind in a spiral, filling outer space with stars and cosmic material. An analogy with cosmic bodies that revolve around the Sun in our star system is appropriate here. A huge mass of stars, large and small, clusters and nebulae, cosmic objects of various sizes and natures, spins on a giant carousel. All of them create a wonderful picture of the starry sky, which people have been looking at for thousands of years. When studying our galaxy, you should know that the stars in the galaxy live according to their own laws, being today in one of the arms of the galaxy, tomorrow they will begin their journey in the other direction, leaving one arm and flying to another.

Earth in the Milky Way galaxy is far from the only planet suitable for life. This is just a particle of dust, the size of an atom, which is lost in the vast star world of our galaxy. There can be a huge number of such Earth-like planets in the galaxy. It is enough to imagine the number of stars that in one way or another have their own stellar planetary systems. Other life may be far away, at the very edge of the galaxy, tens of thousands of light years away, or, conversely, present in neighboring areas that are hidden from us by the arms of the Milky Way.

Planet Earth, solar system, billions of other stars and celestial bodies- all this is our Milky Way galaxy - a huge intergalactic formation, where everything obeys the laws of gravity. Data on the true size of the galaxy are only approximate. And the most interesting thing is that there are hundreds, maybe even thousands, of such formations, larger or smaller, in the Universe.

The Milky Way Galaxy and what surrounds it

All celestial bodies, including the Milky Way planets, satellites, asteroids, comets and stars, are constantly in motion. Born in the cosmic vortex of the Big Bang, all these objects are on the path of their development. Some have more ancient age, others are clearly younger.

The gravitational formation rotates around the center, while individual parts of the galaxy rotate with at different speeds. If in the center the rotation speed of the galactic disk is quite moderate, then at the periphery this parameter reaches values ​​of 200-250 km/s. The Sun is located in one of these areas, closer to the center of the galactic disk. The distance from it to the center of the galaxy is 25-28 thousand light years. The Sun and the Solar System complete a full revolution around the central axis of the gravitational formation in 225-250 million years. Accordingly, in the entire history of its existence, the Solar System has flown around the center only 30 times.

Place of the galaxy in the Universe

One notable feature should be noted. The position of the Sun and, accordingly, the planet Earth is very convenient. The galactic disk is constantly undergoing a process of compaction. This mechanism is caused by the discrepancy between the speed of rotation of the spiral branches and the movement of stars, which move within the galactic disk according to their own laws. During compaction, violent processes occur, accompanied by powerful ultraviolet radiation. The Sun and the Earth are comfortably located in the corotational circle, where such vigorous activity is absent: between two spiral branches on the border of the Milky Way arms - Sagittarius and Perseus. This explains the calm in which we remain so long time. For more than 4.5 billion years, we have not been affected by cosmic disasters.

Structure of the Milky Way galaxy

The galactic disk is not homogeneous in its composition. Like other spiral gravitational systems, the Milky Way has three distinguishable regions:

• a core formed by a dense star cluster containing a billion stars of varying ages;
• the galactic disk itself, formed from clusters of stars, stellar gas and dust;
• corona, spherical halo - the region in which globular clusters, dwarf galaxies are located, separate groups stars, cosmic dust and gas.

Near the plane of the galactic disk there are young stars collected in clusters. The density of star clusters in the center of the disk is higher. Near the center, the density is 10,000 stars per cubic parsec. In the region where the Solar System is located, the density of stars is already 1-2 stars per 16 cubic parsecs. As a rule, the age of these celestial bodies is no more than several billion years.

Interstellar gas also concentrates around the plane of the disk, subject to centrifugal forces. Despite the constant speed of rotation of the spiral branches, the interstellar gas is distributed unevenly, forming large and small zones of clouds and nebulae. However, the main galactic building material is dark matter. Its mass prevails over the total mass of all celestial bodies that make up the Milky Way galaxy.

If in the diagram the structure of the galaxy is quite clear and transparent, then in reality it is almost impossible to examine the central regions of the galactic disk. Gas and dust clouds and clusters of stellar gas hide from our view the light from the center of the Milky Way, in which lives a real space monster - a supermassive black hole. The mass of this supergiant is approximately 4.3 million M☉. Next to the supergiant is a smaller black hole. This gloomy company is complemented by hundreds of dwarf black holes. The black holes of the Milky Way are not only devourers of stellar matter, but also act as a maternity hospital, throwing huge bunches of protons, neutrons and electrons into space. It is from them that atomic hydrogen is formed - the main fuel of the star tribe.

The jumper bar is located in the region of the galactic core. Its length is 27 thousand light years. Old stars reign here, red giants, whose stellar matter feeds black holes. The bulk of molecular hydrogen is concentrated in this region, which acts as the main building material for the star formation process.

Geometrically, the structure of the galaxy looks quite simple. Each spiral arm, and there are four of them in the Milky Way, originates from a gas ring. The sleeves diverge at an angle of 20⁰. At the outer boundaries of the galactic disk, the main element is atomic hydrogen, which spreads from the center of the galaxy to the periphery. The thickness of the hydrogen layer on the outskirts of the Milky Way is much wider than in the center, while its density is extremely low. The discharge of the hydrogen layer is facilitated by the influence of dwarf galaxies, which have been closely following our galaxy for tens of billions of years.

Theoretical models of our galaxy

Even ancient astronomers tried to prove that the visible stripe in the sky is part of a huge stellar disk rotating around its center. This statement was supported by the mathematical calculations carried out. It was possible to get an idea of ​​our galaxy only thousands of years later, when they came to help science instrumental methods space exploration. A breakthrough in the study of the nature of the Milky Way was the work of the Englishman William Herschel. In 1700, he was able to experimentally prove that our galaxy is disk-shaped.

Already in our time, research has taken a different turn. Scientists relied on comparing the movements of stars between which there were different distances. Using the parallax method, Jacob Kaptein was able to approximately determine the diameter of the galaxy, which, according to his calculations, is 60-70 thousand light years. Accordingly, the place of the Sun was determined. It turned out that it is located relatively far from the raging center of the galaxy and at a considerable distance from the periphery of the Milky Way.

The fundamental theory of the existence of galaxies is that of the American astrophysicist Edwin Hubble. He came up with the idea to classify all gravitational formations, dividing them into elliptical galaxies and spiral-type formations. The latter, spiral galaxies, represent the largest group, which includes formations of various sizes. The largest recently discovered spiral galaxies is NGC 6872, whose diameter exceeds 552 thousand light years.

Expected future and forecasts

The Milky Way Galaxy appears to be a compact and orderly gravitational formation. Unlike our neighbors, our intergalactic home is quite calm. Black holes systematically affect the galactic disk, reducing it in size. This process has already lasted tens of billions of years and how much longer it will continue is unknown. The only threat looming over our galaxy comes from its nearest neighbor. The Andromeda Galaxy is rapidly approaching us. Scientists suggest that a collision of two gravitational systems could occur in 4.5 billion years.

Such a meeting-merger will mean the end of the world in which we are accustomed to living. The Milky Way, which is smaller in size, will be absorbed more large education. Instead of two large spiral formations, a new elliptical galaxy will appear in the Universe. Until this time, our galaxy will be able to deal with its satellites. Two dwarf galaxies - the Large and Small Magellanic Clouds - will be absorbed by the Milky Way in 4 billion years.

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Astronomers say that with the naked eye a person can see about 4.5 thousand stars. And this, despite the fact that only a small part of one of the most amazing and unidentified pictures of the world is revealed to our eyes: only in the Galaxy Milky Way there are more than two hundred billion celestial bodies (scientists have the opportunity to observe only two billion).

The Milky Way is a barred spiral galaxy, representing a huge gravitationally bound star system in space. Together with the neighboring Andromeda and Triangulum galaxies and more than forty dwarf satellite galaxies, it is part of the Virgo Supercluster.

The age of the Milky Way exceeds 13 billion years, and during this time from 200 to 400 billion stars and constellations, more than a thousand huge gas clouds, clusters and nebulae were formed in it. If you look at a map of the Universe, you can see that the Milky Way is presented on it in the form of a disk with a diameter of 30 thousand parsecs (1 parsec is equal to 3.086 * 10 to the 13th power of kilometers) and an average thickness of about a thousand light years (one light year

almost 10 trillion kilometers). electromagnetic radiation. According to very rough calculations, the weight of the Galaxy ranges from 5*10 11 to 3*10 12 solar masses.

Like all celestial bodies, the Milky Way rotates around its axis and moves around the Universe. It should be taken into account that when moving, galaxies constantly collide with each other in space and the one that has larger sizes absorbs smaller ones, but if their sizes coincide, active star formation begins after the collision.

Thus, astronomers suggest that in 4 billion years the Milky Way in the Universe will collide with the Andromeda Galaxy (they are approaching each other at a speed of 112 km/s), causing the emergence of new constellations in the Universe.

As for the movement around its axis, the Milky Way moves unevenly and even chaotically in space, since each star system, cloud or nebula located in it has its own speed and orbits different types and forms.

Galaxy structure

If you look closely at a map of space, you can see that the Milky Way is very compressed in the plane and looks like a “flying saucer” (the Solar system is located almost at the very edge of the star system). The Milky Way Galaxy consists of a core, a bar, a disk, spiral arms and a crown.

Core

The core is located in the constellation Sagittarius, where there is a source of non-thermal radiation, the temperature of which is about ten million degrees - a phenomenon characteristic only of the nuclei of galaxies. In the center of the core there is a compaction - a bulge, consisting of large number old stars moving in an elongated orbit, many of which are at the end of their life cycle.

So, some time ago, American astronomers discovered an area here measuring 12 by 12 parsecs, consisting of dead and dying constellations.

At the very center of the core is a supermassive black hole(an area in outer space that has such powerful gravity that even light is unable to leave it), around which a smaller black hole rotates. Together they exert such a strong gravitational influence on nearby stars and constellations that they move along trajectories unusual for celestial bodies in the Universe.

Also, the center of the Milky Way is characterized by an extremely strong concentration of stars, the distance between which is several hundred times less than at the periphery. The speed of movement of most of them is absolutely independent of how far they are from the core, and therefore average speed rotation ranges from 210 to 250 km/s.

Jumper

The bridge, 27 thousand light years in size, crosses the central part of the Galaxy at an angle of 44 degrees to the conventional line between the Sun and the core of the Milky Way. It consists mainly of old red stars (about 22 million), and is surrounded by a gas ring that contains most of the molecular hydrogen, and is therefore a region where stars are formed in the greatest number. According to one theory, such active star formation occurs in the bridge due to the fact that it passes gas through itself, from which constellations are born.

Disk

The Milky Way is a disk consisting of constellations, gas nebulae and dust (its diameter is about 100 thousand light years with a thickness of several thousand). The disk rotates much faster than the corona, which is located at the edges of the Galaxy, while the rotation speed at different distances from the core is unequal and chaotic (varies from zero in the core to 250 km/h at a distance of 2 thousand light years from it).

Gas clouds, as well as young stars and constellations, are concentrated near the plane of the disk.

On the outer side of the Milky Way there are layers of atomic hydrogen, which extend into space one and a half thousand light years from the outer spirals. Despite the fact that this hydrogen is ten times thicker than in the center of the Galaxy, its density is just as many times lower. On the outskirts of the Milky Way, dense accumulations of gas with a temperature of 10 thousand degrees, the dimensions of which exceed several thousand light years, were discovered.

Spiral sleeves

Immediately behind the gas ring there are five main spiral arms of the Galaxy, the size of which ranges from 3 to 4.5 thousand parsecs: Cygnus, Perseus, Orion, Sagittarius and Centauri (the Sun is located on the inner side of the Orion arm). Molecular gas is located unevenly in the arms and does not always obey the rules of rotation of the Galaxy, introducing errors.

Crown

According to one hypothesis, the corona arose as a result of the absorption of smaller galaxies by the Milky Way, and is therefore their remnants. According to preliminary data, the age of the halo exceeds twelve billion years and is the same age as the Milky Way, and therefore star formation here has already completed.

star space

If you look at the night starry sky, the Milky Way can be seen from absolutely any point globe in the form of a strip of lightish color (since our star system is located inside the Orion arm, only part of the Galaxy is accessible for viewing).

The map of the Milky Way shows that our Sun is located almost on the disk of the Galaxy, at its very edge, and its distance to the core is from 26-28 thousand light years. Considering that the Sun moves at a speed of about 240 km/h, to make one revolution, it needs to spend about 200 million years (over the entire period of its existence, our star has not flown around the Galaxy thirty times).

It is interesting that our planet is located in a corotation circle - a place where the speed of rotation of stars coincides with the speed of rotation of the arms, so stars never leave these arms or enter them. This circle is characterized by high level radiation, therefore it is believed that life can only arise on planets near which there are very few stars.

This fact also applies to our Earth. Being on the periphery, it is located in a fairly calm place in the Galaxy, and therefore for several billion years it was almost not subject to global cataclysms, for which the Universe is so rich. Perhaps this is one of the main reasons that life was able to originate and survive on our planet.

MILKY WAY
a hazy glow in the night sky from the billions of stars in our Galaxy. The Milky Way band encircles the sky in a wide ring. The Milky Way is especially visible away from city lights. In the Northern Hemisphere, it is convenient to observe it around midnight in July, at 10 pm in August or at 8 pm in September, when the Northern Cross of the Cygnus constellation is near the zenith. As we follow the Milky Way's shimmering streak north or northeast, we pass the W-shaped constellation Cassiopeia and head toward the bright star Capella. Beyond the Chapel, you can see how the less wide and bright part of the Milky Way passes just east of Orion's Belt and leans towards the horizon not far from Sirius, the brightest star in the sky. The brightest part of the Milky Way is visible to the south or southwest at times when the Northern Cross is overhead. At the same time, two branches of the Milky Way are visible, separated by a dark gap. The Scutum Cloud, which E. Barnard called the “pearl of the Milky Way,” is located halfway to the zenith, and below are the magnificent constellations Sagittarius and Scorpius.

Unfortunately, the brightest parts of the Milky Way are inaccessible to observers Northern Hemisphere. To see them, you need to go to the equator, or even better, position yourself between 20 and 40° S. and watch the sky approx. 10 pm in late April or early May. High in the sky is the Southern Cross, and low in the northwest is Sirius. The faint and narrow Milky Way runs between them, but it becomes much brighter and more interesting 30° west of Southern Cross, in the constellation Carina. As Sagittarius and Scorpio rise in the east, the brightest and most magnificent parts of the Milky Way appear.

Its most remarkable area is visible late in the evening in June-July, when the Sagittarius Cloud is located near the zenith. Against the background of a uniform glow caused by thousands and thousands of distant stars invisible to the eye, one can notice dark clouds and “veins” of cold cosmic dust. Anyone who wants to understand the structure of our Galaxy should take the time to observe the Milky Way - this truly remarkable and most grandiose of celestial phenomena. To discern the myriad stars that make up the Milky Way, all you need is binoculars or a small telescope. The highest concentration of stars and The Milky Way is observed in the constellations Sagittarius and Scorpio; It is least populated with stars on the opposite side of the sky - near Orion's Belt and Capella. Accurate astronomical observations confirm the first visual impression: the band of the Milky Way marks the central plane of a giant disk-shaped star system - our Galaxy, often called the "Milky Way Galaxy". One of its stars is our Sun, located very close to the central plane of the Galaxy. However, the Sun is not at the center of the galactic disk, but at a distance of two-thirds from its center to the edge. The stars that make up the Milky Way are located at different distances from the Earth: some are no further than 100 light years. years, and most are removed by 10,000 sv. years and even further. The star cloud in Sagittarius and Scorpio marks the direction of the center of the Galaxy, located at a distance of approximately 30,000 light years from Earth. years. The diameter of the entire Galaxy is at least 100,000 light years. years.
Composition of the Milky Way. The galaxy consists mainly of stars, more or less similar to the Sun. Some of them are several times more massive than the Sun and glow several thousand times brighter, others are several times less massive and glow several thousand times weaker. The Sun is, in many ways, an average star. Depending on the surface temperature, stars have different colour: blue-white stars are the hottest (20,000-40,000 K), and red stars are the coolest (approx. 2500 K). Some stars form groups called star clusters. Some of them are visible to the naked eye, such as the Pleiades. This is a typical open cluster; Typically such clusters contain from 50 to 2000 stars. In addition to open clusters, there are much larger globular clusters containing up to several million stars. These clusters vary significantly in age and stellar composition. Open clusters are relatively young: their typical age is ca. 10 million years, i.e. OK. 1/500th the age of the Earth and the Sun. They contain many massive bright stars. Globular clusters are very old: 10-15 billion years have passed since their formation, i.e. they consist of the oldest stars in the Galaxy, among which only low-mass ones have survived. Open clusters are located near the galactic plane, where there is a lot of interstellar gas from which stars form. Globular clusters fill the galactic halo surrounding the disk and are noticeably concentrated towards the center of the Galaxy.
see also
GALAXIES;
STARS ;
CONSTELLATION. The mass of the Galaxy is at least 2*10 11 solar masses. These are mostly stars, but 5% of its mass is interstellar matter - gas and dust. Interstellar matter fills the space between stars in the galactic disk with a thickness of approx. 600 St. years, and inside the disk it concentrates towards the spiral arms of the Galaxy. A significant part of the interstellar matter is combined into massive cold clouds, in the depths of which stars form.
see also INTERSTELLAR MATTER. The Milky Way Galaxy is one of hundreds of millions of similar star systems discovered in the Universe using large telescopes. It is often called "our star system." It belongs to large galaxies with rapid rotation and clear spiral arms, in which young hot stars and gas clouds heated by their radiation, called “emission nebulae,” are concentrated. Using optical telescopes, it is not possible to study the entire Galaxy, since light does not penetrate through dense interstellar clouds of gas and dust, which are especially numerous towards the center of the Galaxy. However for infrared radiation and radio emissions, dust is not a hindrance: with the help of appropriate telescopes it is possible to explore the entire Galaxy and even get through to its dense core. Observations have shown that the stars and gas in the galactic disk are moving at a speed of about 250 km/s around the center of the Galaxy. Our Sun, together with the planets, also moves at the same speed, making one revolution around the galactic center in about 200 million years.

Collier's Encyclopedia. - Open Society. 2000 .

Synonyms:

See what "MILKY WAY" is in other dictionaries:

Milky Way Galaxy ( computer model). Barred spiral galaxy. Two of the four branches dominate. Characteristics Type SBbc (spiral galaxy with bar) Diameter ... Wikipedia

MILKY WAY, a faint band of light visible in the sky on clear days dark nights, passing along the line of the galactic equator. It is formed as a result of the glow of a huge number of stars, in some areas covered by clouds of interstellar gas and... ... Scientific and technical encyclopedic dictionary

A wide strip in the sky consisting of countless stars. Wed. The whole sky is strewn with cheerfully twinkling stars, and the Milky Way appears as clearly as if it had been washed and covered with snow before the holiday. A.P. Chekhov. Vanka. See Moiseeva... ... Michelson's Large Explanatory and Phraseological Dictionary (original spelling)

MILKY WAY, 1) a dimly luminous stripe crossing the starry sky. It is a huge number of visually indistinguishable stars concentrating towards the main plane of the Galaxy. The Sun is located near this plane, so... ... Modern encyclopedia

1) a dimly luminous stripe crossing the starry sky. It is a huge number of visually indistinguishable stars concentrating towards the main plane of the Galaxy. The Sun is located near this plane, so most stars... ... Big Encyclopedic Dictionary

MILKY, oh, oh Dictionary Ozhegova. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 … Ozhegov's Explanatory Dictionary

1) Galaxy. 2) A light stripe in the night sky is projected onto celestial sphere distant (from the Sun) stars of the Galaxy, close to its plane. Increase The brightness of this band is due to higher concentration of stars in the galactic plane. Physical... ... Physical encyclopedia

The science

Each person has his own idea of ​​what home is. For some it is a roof over their head, for others a home is planet Earth, a rocky ball that plows through outer space along its closed path around the Sun.

No matter how big our planet may seem to us, it is just a grain of sand in giant star system, the size of which is difficult to imagine. This star system- the Milky Way galaxy, which can also rightfully be called our home.

Galaxy Sleeves

Milky Way- a spiral galaxy with a bar that runs through the center of the spiral. About two thirds of all famous galaxies- spiral, and two thirds of them have a jumper. That is, the Milky Way is included in the list most common galaxies.

Spiral galaxies have arms that extend out from the center, like wheel spokes that twist in a spiral. Our solar system is located in the central part of one of the arms, which is called Orion's sleeve.

The Orion Arm was once thought to be a small "offshoot" of larger arms such as Perseus arm or Shield-Centauri arm. Not long ago, it was suggested that the Orion arm is indeed branch of the Perseus arm and does not leave the center of the galaxy.

The problem is that we cannot see our galaxy from the outside. We can only observe those things that are around us, and judge what shape the galaxy has, being, as it were, inside it. However, scientists were able to calculate that this sleeve has a length of approximately 11 thousand light years and thickness 3500 light years.

Supermassive black hole

The smallest supermassive black holes that scientists have discovered are approximately V 200 thousand times heavier than the sun. For comparison: ordinary black holes have the mass of just 10 times exceeding the mass of the Sun. At the center of the Milky Way is an incredibly massive black hole, the mass of which is difficult to imagine.

For the past 10 years, astronomers have been monitoring the activity of stars in orbit around the star. Sagittarius A, a dense region at the center of the spiral of our galaxy. Based on the movement of these stars, it was determined that in the center Sagittarius A*, which is hidden behind a dense cloud of dust and gas, there is a supermassive black hole whose mass 4.1 million times more than the mass of the Sun!

The animation below shows the actual motion of stars around a black hole. from 1997 to 2011 in the region of one cubic parsec in the center of our galaxy. When stars approach a black hole, they loop around it at incredible speeds. For example, one of these stars, S 0-2 moves at speed 18 million kilometers per hour: black hole first attracts her, and then sharply pushes her away.

Just recently, scientists observed how a cloud of gas approached a black hole and was torn to pieces her massive gravitational field. Parts of this cloud were swallowed up by the hole, and the remaining parts began to resemble long thin noodles longer than 160 billion kilometers.

Magneticparticles

In addition to the presence of a supermassive all-consuming black hole, the center of our galaxy boasts incredible activity: old stars die, and new ones are born with enviable consistency.

Not long ago, scientists noticed something else at the galactic center - a stream of high-energy particles that extend a distance 15 thousand parsecs across the galaxy. This distance is approximately half the diameter of the Milky Way.

The particles are invisible to the naked eye, but magnetic imaging shows that particle geysers occupy approx. two thirds of the visible sky:

What is behind this phenomenon? For one million years, stars appeared and disappeared, feeding never stopping flow, directed towards the outer arms of the galaxy. The total energy of the geyser is a million times greater than the energy of a supernova.

Particles move at incredible speeds. Based on the structure of the particle flow, astronomers built model magnetic field , which dominates our galaxy.

Newstars

How often do new stars form in our galaxy? Researchers asked this question long years. It was possible to map the areas of our galaxy where there is aluminum-26, an isotope of aluminum that appears where stars are born or die. Thus, it was possible to find out that every year in the Milky Way galaxy 7 new stars and approximately twice in a hundred years a large star explodes in a supernova.

The Milky Way Galaxy is not the producer of itself large quantity stars When a star dies, it releases such raw materials into space as like hydrogen and helium. Over hundreds of thousands of years, these particles coalesce into molecular clouds that eventually become so dense that their center collapses under their own gravity, thus forming a new star.

It looks like a kind of eco-system: death feeds new life . Particles from a particular star will be part of a billion new stars in the future. This is how things are in our galaxy, which is why it is evolving. This leads to the formation of new conditions under which the likelihood of the emergence of Earth-like planets increases.

Planets of the Milky Way galaxy

Despite the constant death and birth of new stars in our galaxy, their number has been calculated: the Milky Way is home to approximately 100 billion stars. Based on new research, scientists suggest that every star is orbited by at least one planet or more. That is, in our corner of the Universe there is only from 100 to 200 billion planets.

The scientists who came to this conclusion studied stars like red dwarfs of spectral type M. These stars are smaller than our Sun. They make up 75 percent of all the stars in the Milky Way. In particular, researchers paid attention to the star Kepler-32, which sheltered five planets.

How do astronomers discover new planets?

Planets, unlike stars, are difficult to detect because they do not emit their own light. We can say with certainty that there is a planet around a star only when it stands in front of his star and blocks out its light.

The planets of Kepler -32 behave exactly like exoplanets orbiting other M dwarf stars. They are located approximately at the same distance and have similar sizes. That is, the Kepler -32 system is typical system for our galaxy.

If there are more than 100 billion planets in our galaxy, how many of them are Earth-like planets? It turns out, not so much. There are dozens various types planets: gas giants, pulsar planets, brown dwarfs and planets where molten metal rains from the sky. Those planets that consist of rocks can be located too far or too close to the star, so they are unlikely to resemble Earth.

The results of recent research have shown that there are more planets in our galaxy earth type than previously assumed, namely: from 11 to 40 billion. Scientists took as an example 42 thousand stars, similar to our Sun, and began to look for exoplanets that can orbit them in a zone where it is not too hot and not too cold. Was found 603 exoplanets, among which 10 matched the search criteria.

By analyzing data about stars, scientists have proven the existence of billions of Earth-like planets that they have yet to officially discover. Theoretically, these planets are capable of maintaining temperatures for existence of liquid water on them, which, in turn, will allow life to arise.

Collision of galaxies

Even if new stars are constantly being formed in the Milky Way galaxy, it will not be able to increase in size, if he doesn't receive new material from somewhere else. And the Milky Way is really expanding.

Previously, we were not sure exactly how the galaxy manages to grow, but recent discoveries have suggested that the Milky Way is galaxy-cannibal, meaning it has consumed other galaxies in the past and will likely do so again, at least until some larger galaxy swallows it.

Using a space telescope "Hubble" and information obtained from photographs taken over seven years, scientists have discovered stars at the outer edge of the Milky Way that move in a special way. Instead of moving toward or away from the center of the galaxy like other stars, they appear to drift toward the edge. It is believed that this star cluster is all that remains of another galaxy that was absorbed by the Milky Way galaxy.

This collision apparently occurred several billion years ago and, most likely, it will not be the last. Considering the speed at which we are moving, our galaxy through 4.5 billion years will collide with the Andromeda galaxy.

Influence of satellite galaxies

Although the Milky Way is a spiral galaxy, it is not exactly a perfect spiral. At its center there is peculiar bulge, which appeared as a result of hydrogen gas molecules escaping from the flat disk of the spiral.

During for long years Astronomers have puzzled over why the galaxy has such a bulge. It is logical to assume that the gas is drawn into the disk itself, and does not escape out. The longer they studied this question, the more confused they became: the molecules of the bulge are not only pushed outward, but also vibrate at their own frequency.

What could cause this effect? Today, scientists believe that dark matter and satellite galaxies are to blame - Magellanic Clouds. These two galaxies are very small: taken together they make up only 2 percent from total mass Milky Way. This is not enough to have an impact on him.

However, when dark matter moves through the clouds, it creates waves that apparently influence the gravitational attraction, strengthening it, and hydrogen under the influence of this attraction escapes from the center of the galaxy.

Magellanic Clouds orbit the Milky Way. The spiral arms of the Milky Way, under the influence of these galaxies, seem to sway in the place where they pass.

Twin galaxies

Although the Milky Way galaxy can be called unique in many respects, it is not very rare. Spiral galaxies predominate in the Universe. Considering that only in our field of vision are about 170 billion galaxies, we can assume that somewhere there are galaxies very similar to ours.

What if there is a galaxy somewhere - exact copy Milky Way? In 2012, astronomers discovered such a galaxy. It even has two small moons that orbit it that exactly match our Magellanic Clouds. By the way, only 3 percent spiral galaxies have similar companions, whose lifespan is relatively short. The Magellanic Clouds are likely to dissolve in a couple of billion years.

To discover such a similar galaxy, with satellites, a supermassive black hole in the center and the same size, is incredible luck. This galaxy was named NGC 1073 and it's so similar to the Milky Way that astronomers are studying it to find out more about our own galaxy. For example, we can see it from the side and thus better imagine what the Milky Way looks like.

Galactic year

On Earth, a year is the time during which the Earth manages to make full revolution around the Sun. Every 365 days we return to the same point. Our solar system revolves in the same way around a black hole located at the center of the galaxy. However, it makes a full revolution in 250 million years. That is, since the dinosaurs disappeared, we have only made a quarter of a full revolution.

Descriptions of the solar system rarely mention that it moves through space, like everything else in our world. Relative to the center of the Milky Way, the solar system moves at a speed 792 thousand kilometers per hour. For comparison: if you were moving at the same speed, you could make trip around the world in 3 minutes.

The period of time during which the Sun manages to make a complete revolution around the center of the Milky Way is called galactic year. It is estimated that the Sun has lived only 18 galactic years.