Our Galaxy - Milky Way

© Vladimir Kalanov
"Knowledge is power."

Looking at the night starry sky, you can see a dimly glowing whitish stripe that crosses the celestial sphere. This diffuse glow comes both from several hundred billion stars and from the scattering of light by tiny particles of dust and gas in interstellar space. This is our Milky Way galaxy. The Milky Way is a galaxy to which the solar system with its planets, including the Earth, belongs. It is visible from anywhere on the earth's surface. The Milky Way forms a ring, so from any point on Earth we see only part of it. The Milky Way, which appears to be a dim road of light, is actually made up of a huge number of stars that are not individually visible to the naked eye. He was the first to think about this at the beginning of the 17th century when he pointed the telescope he had made at the Milky Way. What Galileo first saw took his breath away. In the place of the huge whitish strip of the Milky Way, sparkling clusters of countless stars, visible individually, opened up to his gaze. Today scientists believe that the Milky Way contains huge number stars - about 200 billion.

Rice. 1 schematic representation of our Galaxy and the surrounding halo.

The Milky Way is a galaxy consisting of a large flat - main - disk-shaped body with a diameter exceeding a distance of 100 thousand light years. The disk of the Milky Way itself is "relatively thin" - several thousand light years thick. Most of the stars are located inside the disk. In terms of its morphology, the disk is not compact, has a complex structure; inside it there are uneven structures that extend from the core to the periphery of the Galaxy. These are the so-called “spiral arms” of our Galaxy, high-density zones where new stars form from clouds of interstellar dust and gas.

Rice. 2 Center of the Galaxy. Conditional tone image of the center of the Milky Way.

Explanation of the picture: The light source in the middle is Sagittarius A, an active star formation zone, located near the galactic core. The center is surrounded by a gaseous ring (pink circle). The outer ring contains molecular clouds (orange) and ionized hydrogen space in pink.

The galactic core is located in the central part of the Milky Way's disk. The core is made up of billions of old stars. The central part of the core itself is a very massive region with a diameter of only a few light years, inside of which, according to the latest astronomical research, there is a supermassive black hole, possibly even several black holes, with masses of about 3 million Suns.

Around the disk of the Galaxy there is a spherical halo (corona), containing dwarf galaxies (Large and Small Magellanic clouds, etc.), globular star clusters, individual stars, groups of stars and hot gas. Some of separate groups stars interact with globular clusters and dwarf galaxies. There is a hypothesis, arising from an analysis of the structure of the halo and the trajectories of motion of star clusters, that globular clusters, like the galactic corona itself, may be the remnants of former satellite galaxies absorbed by our Galaxy as a result of earlier interactions and collisions.

According to scientific assumptions, our Galaxy also contains dark matter, which is probably much larger than all visible matter in all observation ranges.

Dense regions of gas several thousand light years in size, with a temperature of 10,000 degrees and a mass of 10 million Suns have been discovered on the outskirts of the Galaxy.

Our Sun is almost on the disk, at a distance of about 28,000 light years from the center of the Galaxy. In other words, it is located on the periphery, at a distance of almost 2/3 of the galactic radius from the center, which is a distance of about 8 kiloparsecs from the center of our Galaxy.

Rice. 3 The plane of the Galaxy and the plane of the Solar System do not coincide, but are at an angle to each other.

Position of the Sun in the Galaxy

The position of the Sun in the Galaxy and its movement are also discussed in detail in the “Sun” section of our website (see). To complete a full revolution, the Sun takes about 250 million years (according to some sources, 220 million years), which constitute a galactic year (the speed of the Sun is 220 km/s, that is, almost 800,000 km/h!). Every 33 million years, the Sun crosses the galactic equator, then rises above its plane to a height of 230 light years and descends again towards the equator. It takes, as already mentioned, about 250 million years for the Sun to complete a full revolution.

Since we are inside the Galaxy and looking at it from the inside, its disk appears visible on the celestial sphere as a strip of stars (this is the Milky Way), and therefore it is difficult to determine the real three-dimensional spatial structure of the Milky Way from Earth.

Rice. 4 full sky survey in galactic coordinates obtained at 408 MHz (wavelength 73 cm), shown in false colors.

Radio intensity is displayed on a linear color scale from dark blue (lowest intensity) to red (highest intensity). The angular resolution of the map is approximately 2°. Many well-known radio sources are visible along the galactic plane, including the supernova remnants of Cassiopeia A and the Crab Nebula.
Complexes of local arms (Swan X and Parus X), surrounded by diffuse radio emission, are clearly visible. The diffuse radio emission of the Milky Way is mainly synchrotron electron emission cosmic rays when they interact with magnetic field of our Galaxy.

Rice. 5 Two full-sky images based on data obtained in 1990 by the DIRBE Diffuse Infrared Background Experiment on the COBE satellite.

Both images show strong radiation from the Milky Way. The top photo shows combined emission data at 25, 60 and 100 micron far infrared wavelengths, shown in blue, green and red respectively. This radiation comes from cold interstellar dust. The pale blue background radiation is generated by interplanetary dust in the solar system. The bottom image combines emission data at 1.2, 2.2, and 3.4 microns in the near-infrared, shown in blue, green, and red, respectively.

New map of the Milky Way

The Milky Way can be classified as spiral galaxy. As already said, it consists of a main body in the form of a flat disk with a diameter of more than 100,000 light years, within which lies most of the stars. The disk has a non-compact structure, and its uneven structure is obvious, starting from the core and spreading to the periphery of the Galaxy. These are spiral branches of regions of the highest density of matter, the so-called. spiral arms in which the process of formation of new stars takes place, starting in interstellar gas and dust clouds. Nothing can be said about the reason for the emergence of spiral arms, except that arms always appear in numerical simulations of the birth of a galaxy if the mass and torque are given sufficiently large.

To see the description, touch the cell for a long time To enlarge the image - briefly To return from the image - return key on your phone or browser

A new computer-generated three-dimensional model of the Milky Way with the real location of hundreds of thousands of nebulae and stars.
© National Geographic Society, Washington D.C. 2005.

Rotation of parts of the galaxy

Parts of the galaxy rotate at different speeds around its center. If we could look at the Galaxy “from above,” we would see a dense and bright core, inside which the stars are located very close to each other, as well as arms. In them, stars are concentrated less compactly.

The direction of rotation of the Milky Way, as well as similar spiral galaxies (indicated on the map in the lower left corner when enlarged) is such that the spiral arms seem to twist. And here it is necessary to focus attention on this specific point. During the existence of the Galaxy (at least 12 billion years, according to any modern estimates), the spiral branches would have to spin around the center of the Galaxy several dozen times! And this is not observed either in other galaxies or in ours. Back in 1964, Q. Lin and F. Shu from the USA proposed a theory according to which spiral arms are not some kind of material formations, but waves of matter density that stand out against the smooth background of the galaxy primarily because active star formation is taking place in them, accompanied by the birth of high luminosity stars. The rotation of the spiral arm has nothing to do with the movement of stars in galactic orbits. At short distances from the core, the orbital velocities of stars exceed the velocity of the arm, and stars “flow” into it from the inside and leave from the outside. At large distances, the opposite is true: the arm seems to run towards the stars, temporarily includes them in its composition, and then overtakes them. As for the bright OB stars that determine the pattern of the sleeve, they, having been born in the sleeve, end their relatively short lives in it, not having time to leave the sleeve during their existence.

The gas ring and the movement of stars

According to one of the hypotheses for the structure of the Milky Way, between the center of the Galaxy and the spiral arms there is also the so-called. "gas ring" The gas ring contains billions solar masses gas and dust and is a site of active star formation. This area emits strongly in the radio and infrared range. The study of this formation was carried out using clouds of gas and dust located along the line of sight, and therefore measuring the exact distances to this formation, as well as its exact configuration, is very difficult and there are still two main opinions of scientists on this matter. According to the first, scientists believe that this formation is not a ring, but grouped spirals. According to another opinion, this formation can be considered ring-shaped. Presumably it is located at a distance between 10 and 16 thousand light years from the center.

There is a special branch of astrophysics that studies the movement of stars in the Milky Way, it is called “stellar kinematics”.

To facilitate the task of stellar kinematics, stars are divided into families according to certain characteristics, age, physical data, and location within the Galaxy. The vast majority of young stars concentrated in spiral arms have a rotation speed (relative to the Galactic center, of course) of several kilometers per second. It is believed that such stars had too little time to interact with other stars; they did not “use” mutual attraction to increase their rotation speed. Middle-aged stars have higher speeds.

The most high speed in old stars, they are located on a spherical halo that surrounds our Galaxy up to a distance of 100,000 light years from the center. Their speed exceeds 100 km/s (like globular star clusters).

In internal areas, where they are densely concentrated, the Galaxy in its motion manifests itself similarly to a solid body. In these regions, the speed of rotation of stars is directly proportional to their distance from the center. The rotation curve will appear as a straight line.

At the periphery, the Galaxy in motion is no longer similar to solid. In this part it is not densely “populated” with celestial bodies. The “rotation curve” for the peripheral regions will be “Keplerian”, similar to the rule about the unequal speed of movement of the planets in the Solar System. The rotation speed of stars decreases as they move away from the center of the galaxy.

Star clusters

Located in constant movement not only stars, but also other celestial objects inhabiting the Milky Way: these are open and globular star clusters, nebulae, etc. The movement of globular star clusters - dense formations that include hundreds of thousands of old stars - deserves special study. These clusters have a clear spherical shape; they move around the center of the Galaxy in elongated elliptical orbits inclined to its disk. Their speed of movement is on average about two hundred km/s. Globular star clusters cross the disk at intervals of several million years. Being fairly densely grouped formations, they are relatively stable and do not disintegrate under the influence of the gravity of the Milky Way plane. Things are different with open star clusters. They consist of several hundred or thousands of stars, and they are located mainly in spiral arms. The stars there are not so close to each other. It is believed that open star clusters tend to disintegrate after a few billion years of existence. Globular star clusters are old in terms of formation, they can be about ten billion years old, open clusters are much younger (the count goes from a million to tens of millions of years), very rarely their age exceeds one 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: in the Milky Way Galaxy alone 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).

Astronomers find it difficult to answer exactly how much the Galaxy weighs, since most of the weight is contained not in the constellations, as previously thought, but in dark matter, which does not emit or interact with electromagnetic radiation. According to very rough calculations, the weight of the Galaxy ranges from 5*10 11 to 3*10 12 solar masses.

Like everyone else 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 will 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

The Milky Way's corona appears as a spherical halo that extends five to ten light years beyond the Galaxy. The corona consists of globular clusters, constellations, individual stars (mostly old and low-mass), dwarf galaxies, and hot gas. They all move around the core in elongated orbits, and the rotation of some stars is so random that even the speed of nearby stars can differ significantly, so the corona rotates extremely slowly.

According to one hypothesis, the corona arose as a result of the absorption of smaller galaxies by the Milky Way, and therefore is 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.

We live in a galaxy called the Milky Way. Our planet Earth is just a grain of sand in the Milky Way galaxy. In the course of filling the site, every now and then moments arise that it would seem that I should have written about a long time ago, but were either forgotten, did not have time, or switched to something else. Today we will try to fill one of these niches. Today our topic is the Milky Way galaxy.

Once upon a time, people thought that the center of the World was the Earth. Over time, this opinion was recognized as erroneous and the Sun began to be considered the center of everything. But then it turned out that the star that gives life to all life on the blue planet is by no means the center of outer space, but only a tiny grain of sand in a boundless ocean of stars.

Space, galaxy, Milky way

The cosmos visible to the human eye includes myriads of stars. They all unite into a huge star system, which has a very beautiful and intriguing name - the Milky Way galaxy. From Earth, this celestial splendor is observed in the form of a wide whitish stripe, glowing dimly on the celestial sphere.

She reaches through everything Northern Hemisphere and crosses the constellations Gemini, Auriga, Cassiopeia, Chanterelle, Cygnus, Taurus, Eagle, Sagittarius, Cepheus. Encircles Southern Hemisphere and passes through the constellation Monoceros, Southern Cross, Southern Triangle, Scorpio, Sagittarius, Sails, Compass.

If you arm yourself with a telescope and look through it at the night sky, the picture will be different. The wide whitish stripe will turn into countless luminous stars. Their faint, distant, alluring light will tell without words about the greatness and endless expanses of the Cosmos, will make you hold your breath and realize the insignificance and worthlessness of momentary human problems.

The Milky Way is called Galaxy or a giant star system. According to estimates, there is currently an increasing tendency towards a figure of 400 billion stars in the Milky Way. All these stars move in closed orbits. They are connected to each other by gravitational forces, and most of them have planets. Stars together with planets form star systems. Such systems can be with one star (Solar system), double (Sirius - two stars), triple (Alpha Centauri). There are four, five stars, and even seven.

Milky Way in disk shape

Structure of the Milky Way

All this countless variety of star systems that make up the Milky Way is not scattered haphazardly throughout outer space, but is united into a colossal formation, shaped like a disk with a thickening in the middle. The diameter of the disk is 100,000 light years (one light year corresponds to the distance that light travels in a year, which is approximately 10¹³ km) or 30,659 parsecs (one parsec is 3.2616 light years). The thickness of the disk is several thousand light years, and its mass exceeds the mass of the Sun by 3 × 10¹² times.

The mass of the Milky Way consists of the mass of stars, interstellar gas, dust clouds and a halo, which has the shape of a huge sphere consisting of rarefied hot gas, stars and dark matter. Dark matter appears to be a collection of hypothetical cosmic objects, the masses of which make up 95% of the entire Universe. These mysterious objects are invisible and do not react in any way to modern technical means of detection.

The presence of dark matter can be guessed only by its gravitational effect on visible clusters of suns. There are not so many of them available for observation. The human eye, even enhanced by the most powerful telescope, can only contemplate two billion stars. Everything else outer space hidden by huge impenetrable clouds consisting of interstellar dust and gas.

Thickening ( bulge) in the central part of the Milky Way's disk is called the Galactic center or core. Billions of old stars move in it in very elongated orbits. Their mass is very large and is estimated at 10 billion solar masses. The core dimensions are not that impressive. It is 8000 parsecs across.

Galaxy Core- This is a brightly shining ball. If earthlings could observe it in the sky, then their eyes would see a gigantic luminous ellipsoid, which in size would be a hundred times larger than the Moon. Unfortunately, this most beautiful and magnificent spectacle is inaccessible to people due to powerful gas and dust clouds that obscure the galactic center from planet Earth.

At a distance of 3000 parsecs from the center of the Galaxy there is a gas ring with a width of 1500 parsecs and a mass of 100 million solar masses. It is here that the central region of new star formation is believed to be located. Gas sleeves about 4 thousand parsecs long spread out from it. At the very center of the core there is black hole, with a mass of more than three million Suns.

Galactic disk its structure is heterogeneous. It has separate high-density zones, which are spiral arms. The continuous process of formation of new stars continues in them, and the arms themselves stretch along the core and seem to bend around it in a semicircle. Currently there are five of them. These are the Cygnus arm, the Perseus arm, the Centauri arm and the Sagittarius arm. In the fifth sleeve - Orion's arm- The solar system is located.

Please note - this is a spiral structure. Increasingly, people notice this structure literally everywhere. Many will be surprised, but flight path of our Earth Also there is a spiral!

It is separated from the galactic core by 28,000 light years. Around the center of the Galaxy, the Sun and its planets rush at a speed of 220 km/s, and complete a revolution in 220 million years. True, there is another figure - 250 million years.

The solar system is located just below the galactic equator, and in its orbit it does not move smoothly and calmly, but as if bouncing. Once every 33 million years, it crosses the galactic equator and rises above it to a distance of 230 light years. Then it descends back to repeat its takeoff after another interval of 33 million years.

The galactic disk rotates, but it does not rotate as a single body. The core rotates faster, the spiral arms in the plane of the disk rotate slower. Naturally, a logical question arises: why do the spiral arms not twist around the center of the Galaxy, but always remain the same shape and configuration for 12 billion years (the age of the Milky Way is estimated at this figure).

There is a certain theory that quite plausibly explains this phenomenon. She views spiral arms not as material objects, but as waves of matter density arising against the galactic background. This is caused by star formation and the birth of high luminosity stars. In other words, the rotation of the spiral arms has nothing to do with the movement of stars in their galactic orbits.

The latter, only, pass through the arms either ahead of them in speed if they are closer to the Galactic center, or behind them if they are located in the peripheral regions of the Milky Way. The outlines of these spiral waves are given by brightest stars, which have a very short life and manage to live it without leaving the sleeve.

As can be seen from all of the above, the Milky Way is a very complex cosmic formation, but it is not limited to the surface of the disk. There is a huge spherical cloud around ( halo). It consists of rarefied hot gases, individual stars, globular star clusters, dwarf galaxies and dark matter. On the outskirts of the Milky Way there are dense clouds of gas. Their extent is several thousand light years, their temperature reaches 10,000 degrees, and their mass is equal to at least ten million Suns.

Neighbors of the Milky Way Galaxy

In the vast Cosmos, the Milky Way is far from alone. At a distance of 772 thousand parsecs from it there is an even more huge star system. It's called Andromeda Galaxy(possibly more romantic - Andromeda Nebula). It has been known since ancient times as “a small celestial cloud, easily visible in dark night" Even at the beginning of the 17th century, religiously minded astronomers believed that “in this place the crystal firmament is thinner than usual, and through it the light of the kingdom of heaven pours out.”

The Andromeda Nebula is the only galaxy that can be seen in the sky naked eye. It appears as a small oval luminous spot. The light in it is unevenly distributed: the central part is brighter. If you strengthen your eye with a telescope, the speck will turn into a giant star system, the diameter of which is 150 thousand light years. This is one and a half times the diameter of the Milky Way.

Dangerous neighbor

But Andromeda is not unique in size from the galaxy in which the Solar System exists. Back in 1991, the planetary camera of the space telescope. Hubble recorded the presence of two nuclei. Moreover, one of them is smaller in size and revolves around another, larger and brighter one, gradually collapsing under the influence of the tidal forces of the latter. This slow death throes of one of the cores suggests that it is the remnant of some other galaxy that Andromeda absorbed.

For many, it will be an unpleasant surprise to learn that the Andromeda Nebula is moving towards the Milky Way, and, therefore, towards the Solar System. The approach speed is about 140 km/s. Accordingly, the meeting of two stellar giants will take place somewhere in 2.5-3 billion years. This will not be a meeting on the Elbe, but it will not be a global catastrophe on a cosmic scale either..

Two Galaxies will simply merge into one. But which one will dominate - here the scales tip in favor of Andromeda. It has more mass, and it already has experience in absorbing other galactic systems.

As for the solar system, forecasts vary. The most pessimistic indicates that the Sun with all the planets will simply be thrown into intergalactic space, that is, there will be no place for it in the new formation.

But maybe this is for the better. After all, it is clear from everything that the Andromeda Galaxy is a kind of bloodthirsty monster, devouring its own kind. Having absorbed the Milky Way and destroyed its core, the Nebula will turn into a huge Nebula and continue its path across the expanses of the Universe, eating more and more new galaxies. The end result of this journey will be the collapse of an incredibly swollen, overly gigantic star system.

The Andromeda nebula will disintegrate into countless small stellar formations, exactly repeating the fate of the huge empires of human civilization, which first grew to unprecedented sizes, and then collapsed with a roar, unable to bear the burden of their own greed, self-interest and lust for power.

But you shouldn’t worry about the events of future tragedies. It is better to consider another galaxy, which is called Triangulum Galaxy. It is spread out in the vastness of the Universe at a distance of 730 thousand parsecs from the Milky Way and is two times smaller in size and no less than seven times smaller in mass. That is, this is an ordinary mediocre galaxy, of which there are a great many in Space.

All these three star systems, along with several dozen more dwarf galaxies, are part of the so-called Local Group, which is part of Virgo Supercluster– a huge star formation, the size of which is 200 million light years.

The Milky Way, Andromeda Galaxy and the Triangulum Galaxy have a lot common features. All of them belong to the so-called spiral galaxies. Their disks are flat and consist of young stars, open star clusters and interstellar matter. In the center of each disc there is a thickening (bulge). The main feature, of course, is the presence of bright spiral arms containing many young and hot stars.

The cores of these galaxies are also similar in that they contain clusters of old stars and gas rings in which new stars are born. An invariable attribute of the central part of each nucleus is the presence of a black hole with a very large mass. It has already been mentioned that the mass of the Milky Way black hole corresponds to more than three million masses of the Suns.

Black holes– one of the most impenetrable mysteries of the Universe. Of course, they are observed and studied, but these mysterious formations are in no hurry to reveal their secrets. It is known that black holes have a very high density, and their gravitational field is so powerful that even light cannot escape from them.

But any cosmic body that finds itself in the zone of influence of one of them ( event threshold), will be immediately “swallowed” by this terrible universal monster. What will it be like further fate“unfortunate” is unknown. In short, it’s easy to get into a black hole, but impossible to get out of.

There are many black holes scattered across the expanses of space, some of them have a mass many times greater than the mass of the black hole at the center of the Milky Way. But this does not mean that the monster “native” to the Solar System is more harmless than its larger colleagues. It is also insatiable and bloodthirsty and is a compact (diameter equal to 12.5 light hours) and powerful source of X-ray radiation.

The name of this mysterious object Sagittarius A. Its mass has already been mentioned - more than 3 million solar masses, and the gravitational trap (event threshold) of the baby is measured at 68 astronomical units (1 AU is equal to the average distance of the Earth from the Sun). It is within these limits that lies the limit of his bloodthirstiness and treachery in relation to various cosmic bodies, which, for a number of reasons, frivolously cross it.

Someone probably naively thinks that the baby is content with random victims - nothing like that: he has a constant source of food. This is the star S2. It revolves around the black hole in a very compact orbit - a full revolution is only 15.6 years. Maximum distance S2 from scary monster lies within 5 daylight hours, and the minimum is only 17 daylight hours.

Under the influence of the tidal forces of a black hole, part of its substance is torn off from the star doomed to be slaughtered and flies at great speed towards this terrible cosmic monster. As it approaches, the substance turns into a state of hot plasma and, emitting a farewell bright glow, disappears forever into the insatiable invisible abyss.

But that’s not all: the insidiousness of a black hole has no limits. Next to it there is another, less massive and dense black hole. Its task is to adjust stars, planets, interstellar dust and gas clouds to its more powerful brother. All this also turns into plasma, emits bright light and disappears into nothingness.

However, not all scientists, despite such a demonstrative bloody interpretation of events, are of the opinion that black holes exist. Some argue that this is an unknown mass, driven under a cold, dense shell. It has enormous density and is bursting from the inside, squeezing it with incredible force. This kind of education is called gravastar– gravitational star.

They are trying to fit the entire Universe under this model, thus explaining its expansion. Proponents of this concept argue that outer space is a giant bubble, inflated by an unknown force. That is, the entire Cosmos is a huge gravastor, in which smaller models of gravastors coexist, periodically absorbing individual stars and other formations.

The absorbed bodies are, as it were, thrown into other outer spaces, which are essentially invisible, since they do not let out light from under an absolutely black shell. Maybe gravastors, these are other dimensions or parallel worlds? A specific answer to this question will not be found for a very, very long time.

But it’s not just the presence or absence of black holes that occupies the minds of space researchers. Much more interesting and exciting are thoughts about the existence of intelligent life in other star systems of the Universe.

The Sun, which gives life to earthlings, rotates among many other suns of the Milky Way. Its disk is visible from Earth as a pale shining strip encircling the celestial sphere. These are distant billions and billions of stars, many of which have their own planetary systems. Is there really not one among the countless number of these planets where intelligent beings live - brothers in mind?

The most reasonable assumption is that life similar to Earth could arise on a planet that orbits a star of the same class as the Sun. There is such a star in the sky, and besides, it is located closest to the earthly body star system. This is Alpha Centauri A, located in the constellation Centaurus. From the earth it is visible to the naked eye, and its distance from the Sun is 4.36 light years.

It would be nice, of course, to have reasonable neighbors right next door. But what is desired does not always coincide with reality. Finding signs of an extraterrestrial civilization, even at a distance of some 4-6 light years, is a rather difficult task with current technological advances. Therefore, it is premature to talk about the existence of any intelligence in the constellation Centaurus.

Nowadays, it is only possible to send radio signals into space, hoping that someone unknown will answer the call of human intelligence. The most powerful radio stations in the world have been persistently and non-stop engaged in such activities since the first half of the 20th century. As a result, the level of radio emission from the Earth has increased significantly. The blue planet began to differ sharply in its radiation background from all other planets in the solar system.

Signals from Earth cover outer space with a radius of at least 90 light years. On the scale of the Universe, this is a drop in the ocean, but as you know, this little thing wears away the stone. If somewhere far, far away in Space there is highly developed intelligent life, then, in any case, it must someday turn its attention to both the increased background radiation in the depths of the Milky Way galaxy and the radio signals coming from there. Such an interesting phenomenon will not leave the inquisitive minds of aliens indifferent.

Accordingly, an active search for signals from space has been established. But the dark abyss is silent, which indicates that within the Milky Way there are most likely no intelligent creatures ready to come into contact with the inhabitants of planet Earth, or their technical development is at a very primitive level. The truth suggests another thought, which suggests that a highly developed civilization, or civilizations, exists, but sends some other signals into the expanses of the Galaxy that cannot be picked up by earthly technical means.

Progress on the blue planet is steadily developing and improving. Scientists are developing new, completely different ways to transmit information over long distances. All this can have a positive effect. But we must not forget that the vastness of the Universe is limitless. There are stars, the light from which reaches the Earth after billions of years. In fact, a person sees a picture of the distant past when he observes such a cosmic object through a telescope.

It may happen that the signal received by earthlings from Space will turn out to be the voice of a long-vanished extraterrestrial civilization that lived at a time when neither the Solar System nor the Milky Way existed. The response message from Earth will reach the aliens, who were not even in the project at the time when it was sent.

Well, we must take into account the laws harsh reality. In any case, the search for intelligence in distant galactic worlds cannot be stopped. No luck to current generations, the future will be lucky. Hope in this case will never die, and perseverance and perseverance will undoubtedly pay off handsomely.

But the exploration of galactic space seems quite realistic and close. Already in the next century, fast and graceful stars will fly to the nearest constellations. spaceships. The astronauts on board will observe through their windows not the planet Earth, but the entire solar system. They will see her in the form of a distant, bright star. But this will not be the cold, soulless shine of one of the countless suns of the Galaxy, but the native radiance of the Sun, around which Mother Earth will revolve as an invisible, soul-warming speck of dust.

Very soon, the dreams of science fiction writers, reflected in their works, will become an ordinary everyday reality, and a walk along the Milky Way will become a rather boring and tedious activity, like, for example, a trip in a subway car from one end of Moscow to the other.

The Milky Way is part of a gigantic cluster of stars visible from Earth - our Galaxy, one of hundreds of billions of other similar systems. Together they form the Universe.

If you look at the stars on a clear moonless night somewhere far from city lights, you can clearly see a light stripe crossing the sky - the Milky Way. In fact, this is the light of many stars that make up our Galaxy.

Scientific research has proven that what the ancient poets called the spilled milk of the goddess Hera and the road to heaven turned out to be a visible part of a huge structure with a diameter of about 100 thousand light years, consisting of billions of stars, interstellar matter, nebulae and other celestial bodies. Our Solar System is also part of the Milky Way.

Our star neighbors

In other words, the Milky Way is nothing more than our Galaxy, which we look at from the inside and, moreover, “edge-on”. Visible from Earth more stars in the Milky Way band than outside it. Thanks to our position on the periphery of the Galaxy, on clear nights we have the opportunity to observe its densest regions.

We live in the Solar System, and besides our star, the Galaxy is inhabited by more than 200 billion other stars. They form a star system with a spiral structure. From the side it resembles a disk. If you look from the Earth in a direction perpendicular to the plane of the disk, then there will be very few stars in the field of view. The disk itself is visible as a milky-white stripe crossing the sky. When observed in a direction parallel to the plane of the disk, a huge number of densely located stars are visible, behind which most of the Galaxy lies.

The center of the Galaxy is 28,360 light years away

Astronomers have had a difficult time determining the shape of our Galaxy and the position of its center, since much of the visible radiation from stars on the way to Earth is absorbed by interstellar gas and cosmic dust. By studying the spheroidal halo surrounding the galactic disk, astronomers discovered globular star clusters. Each cluster contains up to several million stars - relics of an era when the disk in the Galaxy had not yet formed. By determining the position of these clusters, scientists were able to calculate where the center of the Galaxy is located. It turned out that it is located in the constellation Sagittarius at a distance of 28,360 light years from us.

Halo, sleeves and bulge

Like other spiral galaxies, the Milky Way has a center from which arms radiate out in a spiral, like a wheel of fire at a fireworks display. At the center of the Galaxy there is a dense thickening (bulge). The galactic core is the most central part of the bulge. The diameter of the bulge is about 20 thousand light years, and the thickness of the disk in this place is about 3200 light years.

Although the core is a very difficult object to study, it is clear that colossal energy is concentrated in it. Therefore, it is of great interest to astrophysicists. Scientists have put forward many hypotheses to describe its structure and evolution. One of them paints a particularly scary picture: the high density of stars in the area of ​​the bulge can lead to gravitational collapse and the formation of supermassive black holes that will suck in the surrounding matter.

In the arms of the Galaxy there are many stars of different ages: old, very bright and young and even unborn. Because of great strength gravity, the density of matter in the arms is increased. Solar system, of which ours is a part tiny planet, is located in one of these spiral arms - the Orion Arm.

Therefore, the entire Galaxy is not visible from Earth. Just as the Earth revolves around the Sun, the Solar System also revolves around the center of the Galaxy in the company of many other stars. This entire large, complex structure is just a tiny part of an even more vast and complex structure - the Universe.

Variety of galaxies

Advances in the creation of astronomical instruments and instruments have made it possible to conduct detailed studies of many areas of the sky, including numerous nebulae. Previously, it was completely unknown what they were. It was assumed that these could be globular clusters (dense spherical groups consisting of hundreds of thousands of old stars), stellar remnants, gas clouds and possibly other galaxies. But with the advent of more advanced telescopes, galaxies began to appear more and more clearly against the backdrop of millions and millions of stars captured on photographic plates. Now astronomers have learned to determine their size and distance from the Earth.

Based on their shape, galaxies are classified into spiral (with arms extending in a spiral from the center), barred spiral (with arms extending from the ends of the bar - a highly elongated core), elliptical and irregular (without a specific shape). Each individual galaxy contains up to several hundred billion stars. By measuring the distance to galaxies, we can determine their nature. relative position in space. It turned out that galaxies form clusters, which in turn unite into superclusters. So-called stellar population types have been identified: Population I stars, generally younger, are located in the galactic disk, while older Population II stars are found in spheroidal haloes and globular clusters.

There are more galaxies in the Universe than there are stars in our Galaxy. Stars are the basic elements from which they are built. Each galaxy consists of approximately 100 billion of these “building blocks,” and hundreds of billions of galaxies in turn form the Universe. So the Milky Way is an extremely small part of a huge and complex universe.

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> Milky Way

Milky Way– spiral galaxy with solar system: interesting facts, size, area, detection and name, study with video, structure, location.

The Milky Way is a spiral galaxy covering an area of ​​100,000 light years in which the solar system is located.

If you have a place far from the city, where it is dark and open beautiful view looking at the starry sky, you may notice a faint light stripe. This is a group with millions of small bright lights and glowing halos. The stars are before you Milky Way galaxy.

But what is she? To begin with, the Milky Way is a barred spiral galaxy that is home to the Solar System. It is difficult to call the home galaxy something unique, because there are hundreds of billions of other galaxies in the Universe, many of which are similar.

Interesting facts about the Milky Way galaxy

• The Milky Way began to form as a cluster of dense regions after Big Bang. The first stars to appear were in globular clusters, which continue to exist. These are the oldest stars in the galaxy;
• The galaxy increased its parameters due to absorption and merger with others. It is now taking stars from the Sagittarius Dwarf Galaxy and the Magellanic Clouds;
• The Milky Way moves through space with an acceleration of 550 km/s relative to the cosmic microwave background radiation;
• The supermassive black hole Sagittarius A* lurks at the galactic center. Its mass is 4.3 million times greater than that of the sun;
• Gas, dust and stars rotate around the center at a speed of 220 km/s. This is a stable indicator, implying the presence of a dark matter shell;
• In 5 billion years, a collision with the Andromeda Galaxy is expected. Some believe that the Milky Way is a giant spiral double system;

Discovering and naming the Milky Way galaxy

Our Milky Way galaxy has a rather interesting name, as the hazy haze resembles a trail of milk. The name has ancient roots and is translated from the Latin “Via Lactea”. This name appears already in the work “Tadhira” by Nasir ad-Din Tusi. He wrote: “Represented by many small and densely grouped stars. They are located close together, so they appear like spots. The color resembles milk...” Admire a photo of the Milky Way galaxy with its arms and center (of course, no one can take a photo of our galaxy, but there are similar designs and precise structural data that provide an idea of ​​​​the appearance of the galactic center and arms).

Scientists thought that the Milky Way was filled with stars, but this remained only a guess until 1610. It was then that Galileo Galilei pointed the first telescope into the sky and saw individual stars. It also revealed a new truth to people: there are many more stars than we thought, and they are part of the Milky Way.

Immanuel Kant in 1755 believed that the Milky Way is a collection of stars united by a shared gravity. Gravitational force causes objects to rotate and flatten into a disk shape. In 1785, William Herschel tried to recreate the galactic shape, but did not realize that most of it was hidden behind a haze of dust and gas.

The situation changes in the 1920s. Edwin Hubble managed to convince us that we do not see spiral nebulae, but individual galaxies. It was then that the opportunity arose to realize our form. From that moment it became clear that this was a barred spiral galaxy. Watch the video to explore the structure of the Milky Way galaxy and explore its globular clusters and find out how many stars live in the galaxy.

Our galaxy: a view from the inside

Astrophysicist Anatoly Zasov about the main components of our galaxy, the interstellar medium and globular clusters:

Location of the Milky Way Galaxy

The Milky Way in the sky is quickly recognized thanks to its wide and elongated white line, reminiscent of a milky trail. Interestingly, this star group has been available for viewing since the formation of the planet. In fact, this area acts as the galactic center.

The galaxy extends 100,000 light years in diameter. If you were able to look at it from above, you would notice a bulge in the center, from which 4 large spiral arms emanate. This type represents 2/3 of the universe's galaxies.

Unlike the usual spiral, specimens with a jumper contain a rod in the center with two branches. Our galaxy has two main arms and two minor ones. Our system is located in the Orion Arm.

The Milky Way is not static and rotates in space, carrying all objects with it. The solar system moves around the galactic center at a speed of 828,000 km/h. But the galaxy is incredibly huge, so one passage takes 230 million years.

Spiral arms accumulate a lot of dust and gas, creating excellent conditions for the formation of new stars. The arms extend from the galactic disk, spanning approximately 1,000 light years.

At the center of the Milky Way you can see a bulge filled with dust, stars and gas. This is why you only get to see a small percentage of total number galactic stars. It's all about the thick gas and dust haze that blocks the view.

In the very center lies a supermassive black hole, billions of times more massive than the Sun. Most likely, it used to be much smaller, but a regular diet of dust and gas allowed it to grow. This is an incredible glutton, because sometimes even stars are sucked in. Of course, it is impossible to see it directly, but the gravitational influence is monitored.

Around the galaxy is a halo of hot gas, where old stars and globular clusters live. It extends over hundreds of thousands of light years, but contains only 2% of the stars that are in the disk. Let's not forget about dark matter (90% of the galactic mass).

Structure and composition of the Milky Way galaxy

When observed, it is clear that the Milky Way divides the celestial space into two almost identical hemispheres. This suggests that our system is located near the galactic plane. It is noticeable that the galaxy has a low level of surface brightness due to the fact that gas and dust are concentrated in the disk. This not only makes it impossible to see the galactic center, but also to understand what is hiding on the other side. You can easily spot the center of the Milky Way galaxy in the diagram below.

If you were able to escape beyond the Milky Way and get a top-down perspective, you would see a spiral with a bar. It extends over 120,000 light years and is 1000 light years wide. For many years, scientists thought they saw 4 arms, but there are only two of them: Scutum-Centauri and Sagittarius.

The arms are created by dense waves rotating around the galaxy. They move around the area, so they compress dust and gas. This process starts active birth stars This happens in all galaxies of this type.

If you have come across photos of the Milky Way, then they are all artistic interpretations or other similar galaxies. It was difficult for us to comprehend its appearance, since we are located inside. Imagine that you want to describe the outside of a house if you have never left its walls. But you can always look out the window and look at the neighboring buildings. In the bottom picture you can easily understand where the Solar System is located in the Milky Way galaxy.

Ground and space missions have revealed that the galaxy is home to 100-400 billion stars. Each of them can have one planet, that is, the Milky Way galaxy is capable of housing hundreds of billions of planets, 17 billion of which are similar in size and mass to Earth.

Approximately 90% of the galactic mass goes to dark matter. No one can explain what we are facing. In principle, it has not yet been seen, but we know about its presence thanks to the rapid galactic rotation and other influences. It is this that keeps galaxies from being destroyed during rotation. Watch the video to learn more about the stars of the Milky Way.

Stellar population of the galaxy

Astronomer Alexey Rastorguev on the age of stars, star clusters and properties of the galactic disk:

Position of the Sun in the Milky Way Galaxy

Between the two main arms is the Orion Arm, in which our system is located 27,000 light-years from the center. There is no point in complaining about the remoteness, because a supermassive black hole (Sagittarius A*) lurks in the central part.

It takes our star, the Sun, 240 million years to orbit the galaxy (a cosmic year). This sounds incredible, because the last time the Sun was in this area, dinosaurs roamed the Earth. During its entire existence, the star made approximately 18-20 flybys. That is, it was born 18.4 space years ago, and the age of the galaxy is 61 space years.

Collision trajectory of the Milky Way galaxy

The Milky Way not only rotates, but also moves in the Universe itself. And although the space is large, no one is immune from collisions.

It is estimated that in about 4 billion years, our Milky Way galaxy will collide with the Andromeda galaxy. They are approaching at a speed of 112 km/s. After the collision, the process of star birth is activated. Overall, Andromeda is not the neatest racer, as it has crashed into other galaxies in the past (noticeably large dust ring in the center).

But earthlings should not worry about the future event. After all, by that time the Sun will already explode and destroy our planet.

What's next for the Milky Way galaxy?

It is believed that the Milky Way was created by the merger of smaller galaxies. This process continues, as the Andromeda Galaxy is already rushing towards us to create a giant ellipse in 3-4 billion years.

The Milky Way and Andromeda do not exist in isolation, but are part of the Local Group, which is also part of the Virgo Supercluster. This gigantic region (110 million light years) is home to 100 groups and galaxy clusters.

If you haven’t been able to admire your native galaxy, then do it as soon as possible. Find a quiet and dark place with open air and just enjoy this amazing star collection. Let us remind you that the site has a virtual 3D model of the Milky Way galaxy, which allows you to study all the stars, clusters, nebulae and famous planets online. And our star map will help you find all these celestial bodies in the sky yourself if you decide to buy a telescope.

Position and movement of the Milky Way