The Milky Way is our galaxy message. Milky Way

Our galaxy. Mysteries of the Milky Way

To some extent, we know more about distant star systems than about our own galaxy - Milky Way. It is more difficult to study its structure than the structure of any other galaxies, because it has to be studied from the inside, and much is not so easy to see. Interstellar dust clouds absorb the light emitted by myriads of distant stars.

Only with the development of radio astronomy and the advent of infrared telescopes, scientists were able to understand how our galaxy works. But many details remain unclear to this day. Even the number of stars in the Milky Way is estimated quite roughly. The newest electronic directories give numbers from 100 to 300 billion stars.

Not so long ago, it was believed that our Galaxy has 4 large arms. But in 2008, astronomers at the University of Wisconsin published the results of processing some 800,000 infrared images taken by the Spitzer space telescope. Their analysis showed that the Milky Way has only two arms. As for the other arms, they are only narrow side branches. So, the Milky Way is a spiral galaxy with two arms. It should be noted that most spiral galaxies known to us also have only two arms.

“Thanks to the Spitzer telescope, we have the opportunity to rethink the structure of the Milky Way,” said astronomer Robert Benjamin of the University of Wisconsin, speaking at a conference of the American Astronomical Society. “We are refining our understanding of the Galaxy in the same way that the discoverers centuries ago, traveling through the globe, refined and rethought previous ideas about what the Earth looks like.

Since the early 1990s, infrared observations have been increasingly changing our knowledge of the structure of the Milky Way, because infrared telescopes make it possible to look through gas and dust clouds and see what is inaccessible to conventional telescopes.

2004 - the age of our galaxy was estimated at 13.6 billion years. It arose shortly after. Initially, it was a diffuse gas bubble containing mainly hydrogen and helium. Over time, it turned into a huge spiral galaxy in which we now live.

general characteristics

But how did the evolution of our galaxy proceed? How did it form - slowly or, on the contrary, very quickly? How was it saturated with heavy elements? How the shape of the Milky Way and its chemical composition? Detailed answers to these questions have yet to be given by scientists.

The length of our Galaxy is about 100,000 light years, and the average thickness of the galactic disk is about 3,000 light years (the thickness of its convex part - the bulge - reaches 16,000 light years). However, in 2008, Australian astronomer Brian Gensler, after analyzing the results of observations of pulsars, suggested that the galactic disk is probably twice as thick as is commonly believed.

Is our galaxy big or small by cosmic standards? For comparison: the extent of the Andromeda Nebula, the nearest large galaxy to us, is approximately 150,000 light-years.

In late 2008, researchers determined using radio astronomy that the Milky Way was spinning faster than previously thought. Judging by this indicator, its mass is approximately one and a half times higher than it was commonly believed. According to various estimates, it varies from 1.0 to 1.9 trillion solar masses. Again, for comparison: the mass of the Andromeda nebula is estimated at the least at 1.2 trillion solar masses.

The structure of galaxies

Black hole

So, the Milky Way is not inferior in size to the Andromeda Nebula. “We should no longer treat our galaxy as a younger sister Andromeda Nebula,” said astronomer Mark Reid of the Smithsonian Center for Astrophysics at Harvard University. At the same time, since the mass of our Galaxy is greater than expected, its attractive force is also higher, which means that the probability of its collision with other galaxies in our vicinity also increases.

Our Galaxy is surrounded by a globular halo, reaching 165,000 light-years across. Astronomers sometimes refer to the halo as the "galactic atmosphere." It contains approximately 150 globular clusters, as well as no a large number of ancient stars. The rest of the halo space is filled with rarefied gas and dark matter. The mass of the latter is estimated at about a trillion solar masses.

The spiral arms of the Milky Way contain huge amounts of hydrogen. This is where stars continue to be born. Over time, young stars leave the arms of galaxies and "move" into the galactic disk. However, the most massive and bright stars live quite a short time, therefore they do not have time to move away from their place of birth. It is no coincidence that the arms of our Galaxy glow so brightly. Most of the Milky Way is made up of small, not very massive stars.

The central part of the Milky Way is located in the constellation Sagittarius. This area is surrounded by dark gas and dust clouds, beyond which nothing can be seen. Only since the 1950s, using the means of radio astronomy, have scientists been able to gradually see what lurks there. A powerful radio source, called Sagittarius A, was discovered in this part of the Galaxy. As observations have shown, a mass is concentrated here that exceeds the mass of the Sun by several million times. The most acceptable explanation for this fact is only one: at the center of our Galaxy is located.

Now, for some reason, she has given herself a break and is not particularly active. The influx of matter here is very scarce. Maybe in time the black hole will have an appetite. Then it will again begin to absorb the veil of gas and dust surrounding it, and the Milky Way will add to the list of active galaxies. It is possible that before this, stars will begin to rapidly emerge in the center of the Galaxy. Similar processes are likely to be repeated regularly.

2010 - American astronomers using the Fermi Space Telescope, designed to observe sources of gamma radiation, discovered two mysterious structures in our Galaxy - two huge bubbles emitting gamma radiation. The diameter of each of them is on average 25,000 light years. They scatter from the center of the Galaxy in the northern and south directions. Perhaps we are talking about the streams of particles that were once emitted by a black hole located in the middle of the Galaxy. Other researchers believe that we are talking about gas clouds that exploded during the birth of stars.

There are several dwarf galaxies around the Milky Way. The most famous of them are the Large and Small Magellanic Clouds, which are associated with milky way a kind of hydrogen bridge, a huge plume of gas that stretches behind these galaxies. It is called the Magellanic Stream. Its length is about 300,000 light years. Our Galaxy is constantly engulfing the nearest dwarf galaxies, in particular the Sagitarius Galaxy, which is located at a distance of 50,000 light-years from the galactic center.

It remains to add that the Milky Way and the Andromeda Nebula are moving towards each other. Presumably in 3 billion years, both galaxies will merge together, forming a larger elliptical galaxy, which has already been called the Milky Honey.

Origin of the Milky Way

Andromeda's nebula

For a long time it was believed that the Milky Way formed gradually. 1962 - Olin Eggen, Donald Linden-Bell and Allan Sandage proposed a hypothesis that became known as the ELS model (it was named after the initial letters of their surnames). According to her, a homogeneous cloud of gas once slowly rotated in place of the Milky Way. It resembled a ball and reached a diameter of approximately 300,000 light years, and consisted mainly of hydrogen and helium. Under the influence of gravity, the protogalaxy contracted and became flat; at the same time, its rotation accelerated noticeably.

For almost two decades, this model suited scientists. But new observational results have shown that the Milky Way could not have arisen as theorists prescribed it.

According to this model, the halo is formed first, and then the galactic disk. But there are also very ancient stars in the disk, for example, the red giant Arcturus, whose age is more than 10 billion years, or numerous white dwarfs of the same age.

Both in the galactic disk and in the halo, globular clusters have been found that are younger than the ELS model allows. Obviously, they are absorbed by our later Galaxy.

Many stars in the halo rotate in a different direction than the Milky Way. Maybe they, too, were once outside the Galaxy, but then they were drawn into this "stellar whirlwind" - like a random swimmer in a whirlpool.

1978 - Leonard Searle and Robert Zinn proposed their own model for the formation of the Milky Way. It was designated as "Model SZ". Now the history of the Galaxy has become noticeably more complicated. Not so long ago, her youth, in the view of astronomers, was described as simply as in the opinion of physicists - a straightforward forward movement. The mechanics of what was happening was clearly visible: there was a homogeneous cloud; it consisted only of evenly spread gas. Nothing by its presence complicated the calculations of theorists.

Now, instead of one huge cloud in the visions of scientists, several small, bizarrely scattered clouds appeared at once. Stars were visible among them; however, they were located only in the halo. Inside the halo, everything was seething: the clouds collided; gas masses were mixed and compacted. Over time, a galactic disk formed from this mixture. New stars began to appear in it. But this model was subsequently criticized.

It was impossible to understand what connected the halo and the galactic disk. This thickening disk and the sparse stellar envelope around it had little in common. Even after Searle and Zinn made their model, it turned out that the halo rotates too slowly to form a galactic disk from it. Judging by the distribution of chemical elements, the latter arose from protogalactic gas. Finally, the angular momentum of the disk turned out to be 10 times higher than that of the halo.

The whole secret is that both models contain a grain of truth. The trouble is that they are too simple and one-sided. Both of them now seem to be fragments of the same recipe by which the Milky Way was created. Eggen and his colleagues read a few lines from this recipe, Searle and Zinn a few others. Therefore, trying to re-imagine the history of our Galaxy, we now and then notice familiar lines that have already been read once.

Milky Way. computer model

So, it all started shortly after the Big Bang. “Today, it is commonly believed that fluctuations in the density of dark matter gave rise to the first structures, the so-called dark halos. Thanks to the force of gravity, these structures did not fall apart, ”says German astronomer Andreas Burkert, author of a new model for the birth of the Galaxy.

Dark halos have become embryos - nuclei - of future galaxies. Around them, under the influence of gravity, gas accumulated. A homogeneous collapse occurred, as described by the ELS model. Already 500-1000 million years after the Big Bang, gas clusters surrounding dark halos became the "incubators" of stars. Small protogalaxies appeared here. In dense clouds of gas, the first globular clusters arose, because stars were born here hundreds of times more often than anywhere else. Protogalaxies collided and merged with each other - this is how large galaxies were formed, including our Milky Way. Today it is surrounded by dark matter and a halo of single stars and their globular clusters, these ruins of a universe that is over 12 billion years old.

There were many very massive stars in protogalaxies. In less than a few tens of millions of years, most of them exploded. These explosions enriched the gas clouds with heavy chemical elements. Therefore, in the galactic disk, not such stars were born as in the halo - they contained hundreds of times more metals. In addition, these explosions generated powerful galactic vortices that heated up the gas and swept it out of the protogalaxies. There was a separation of gas masses and dark matter. This was the most important stage in the formation of galaxies, not previously taken into account in any model.

At the same time, dark halos collided with each other more and more often. Moreover, protogalaxies were stretched out or disintegrated. These catastrophes are reminiscent of the chains of stars preserved in the halo of the Milky Way from the time of "youth". By studying their location, it is possible to evaluate the events that took place in that era. Gradually, a vast sphere formed from these stars - the halo we see. As it cooled, gas clouds penetrated into it. Their angular momentum was preserved, so they did not shrink into a single point, but formed a rotating disk. All this happened over 12 billion years ago. The gas was now compressed as described in the ELS model.

At this time, the "bulge" of the Milky Way is also formed - its middle part, resembling an ellipsoid. The bulge is made up of very old stars. It probably arose during the merger of the largest protogalaxies, which held the gas clouds the longest. In the middle of it were neutron stars and tiny black holes - relics of exploding supernovae. They merged with each other, simultaneously absorbing gas flows. Perhaps this is how the huge black hole was born, which is now in the center of our Galaxy.

The history of the Milky Way is much more chaotic than previously thought. Our own Galaxy, impressive even by cosmic standards, was formed after a series of impacts and mergers - after a series of cosmic catastrophes. Traces of those ancient events can still be found today.

So, for example, not all stars in the Milky Way revolve around the galactic center. Probably, over the billions of years of its existence, our Galaxy has "absorbed" many fellow travelers. Every tenth star in the galactic halo is less than 10 billion years old. By that time, the Milky Way had already formed. Perhaps these are the remains of once captured dwarf galaxies. A group of British scientists from the Astronomical Institute (Cambridge), led by Gerard Gilmour, calculated that the Milky Way could obviously absorb from 40 to 60 Carina-type dwarf galaxies.

In addition, the Milky Way attracts huge masses of gas towards itself. So, in 1958, Dutch astronomers noticed many small spots in the halo. In fact, they turned out to be gas clouds, which consisted mainly of hydrogen atoms and rushed towards the galactic disk.

Our Galaxy will not moderate its appetite in the future. Perhaps it will absorb the nearest dwarf galaxies - Fornax, Carina and, probably, Sextans, and then merge with the Andromeda Nebula. Around the Milky Way - this insatiable "star cannibal" - will become even more deserted.

We live in a galaxy called the Milky Way. Our planet Earth is only a grain of sand in the Milky Way galaxy. In the course of filling the site every now and then, moments appear that it would seem that it was necessary to write about a long time ago, but then they forgot, then they didn’t 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 people thought that the center of the World is the Earth. Over time, this opinion was recognized as erroneous and began to be considered the center of the entire Sun. But then it turned out that the luminary, which 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 the boundless ocean of stars.

space, galaxy, milky way

The cosmos visible to the human eye includes myriads of stars. All of them are combined into a huge star system, which is called very beautifully and intriguingly - the Milky Way galaxy. From Earth, this celestial splendor is observed in the form of a wide whitish band, dimly glowing on the celestial sphere.

It stretches across the entire northern hemisphere and crosses the constellations of Gemini, Auriga, Cassiopeia, Chanterelle, Cygnus, Taurus, Eagle, Arrow, Cepheus. Encircles the southern hemisphere and passes through the constellations of Unicorn, Southern Cross, Southern Triangle, Scorpio, Sagittarius, Sails, Compasses.

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

The milky way is called galaxy or a giant star system. Estimates are currently leaning more and more towards the figure of 400 billion stars in the Milky Way. All these stars move in closed orbits. They are connected to each other by the forces of gravity, and most of them have planets. Stars and planets form stellar systems. Such systems are with one star (solar system), double (Sirius - two stars), triple (alpha Centauri). There are four, five stars, and even seven.

Milky Way in the form of a disk

The structure of the Milky Way

All this countless variety of stellar systems that make up the Milky Way is not scattered across outer space at random, but is combined into a colossal formation that has the shape of 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 about 10¹³ km) or 30,659 parsecs (one parsec is 3.2616 light years). The thickness of the disk is equal to several thousand light-years, and its mass exceeds the mass of the Sun by 3 × 10¹² times.

The mass of the Milky Way is made up of a 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 is represented as a set of hypothetical space 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 only be guessed from its gravitational effect on visible clusters of suns. There are not so many of those available for observation. The human eye, even when amplified by the most powerful telescope, can only see two billion stars. The rest of outer space is hidden by huge impenetrable clouds, consisting of interstellar dust and gas.

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

galactic core is a brightly shining ball. If earthlings could observe it in the sky, then a giant luminous ellipsoid would appear to their eyes, which in size would be a hundred times larger than the moon. Unfortunately, this most beautiful and magnificent sight is inaccessible to people because of the 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 1500 parsecs wide and with a mass of 100 million solar masses. It is here, as expected, that the central region of the formation of new stars is located. Gas sleeves about 4 thousand parsecs long scatter from it. At the very center of the nucleus is black hole , with a mass of more than three million suns.

galactic disk structurally heterogeneous. It has separate high-density zones, which are spiral arms. In them, the continuous process of the formation of new stars continues, and the arms themselves stretch along the core and, as it were, go around it in a semicircle. There are currently five of them. These are the Cygnus arm, the Perseus arm, the Centaurus arm and the Sagittarius arm. In the fifth sleeve - arm of Orion- The solar system is located.

Please note - this is a spiral structure. Increasingly, people notice this structure literally everywhere. Many will be surprised, but the flight path of our Earth with you 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 with its planets rushes at a speed of 220 km / s, and makes a complete 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 at a distance of 230 light years. Then it descends back to repeat its rise through the next interval of 33 million years.

The galactic disk rotates, but it does not rotate as a single body. The nucleus rotates faster, the spiral arms in the disk plane are slower. Naturally occurs legitimate question: why spiral arms do 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 such a figure).

There is a theory that quite plausibly explains this phenomenon. She considers spiral arms not as material objects, but as matter density waves 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 motion 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 lagging behind, if they are located in the peripheral regions of the Milky Way. The outlines of these spiral waves are given by the 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 the most complex space formation, but it is not limited to the surface of the disk. Around there is a huge cloud of spherical shape ( halo). It consists of: rarefied hot gases, individual stars, globular star clusters, dwarf galaxies and dark matter. There are dense clouds of gas on the outskirts of the Milky Way. Their length is several thousand light years, the temperature reaches 10,000 degrees, and the mass is equal to at least ten million suns.

Neighbors of the Milky Way Galaxy

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

The Andromeda Nebula is the only galaxy you can see in the sky naked eye. It is seen as a small oval luminous spot. The light in it is distributed unevenly: central part brighter. If you strengthen the eye with a telescope, then 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 does not differ in size from the galaxy in which the solar system exists. Back in 1991, the planetary camera of the Space Telescope. Hubble recorded that it had two nuclei. Moreover, one of them is smaller and revolves around another, larger and brighter, gradually collapsing under the influence of the tidal forces of the latter. This slow agony of one of the cores suggests that it is the remnant of some other galaxy, swallowed up by Andromeda.

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 the two stellar giants will take place somewhere in 2.5-3 billion years. It 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 are tilted in favor of Andromeda. It has more mass, besides, it already has experience of absorbing other galactic systems.

As for the solar system, then the forecasts vary. The most pessimistic one 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 that's for the best. After all, everything shows that the Andromeda Galaxy is a kind of bloodthirsty monster devouring its own kind. Having swallowed the Milky Way and destroyed its core, the Nebula will turn into a huge Nebula and continue its journey through 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, super-giant 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 proportions, and then collapsed with a roar, unable to withstand the burden of their own greed, self-interest and lust for power.

But do not bother with the events of future tragedies. It is better to consider another galaxy, which is called Triangulum Galaxies. It is spread out in the expanses of the Universe at a distance of 730 thousand parsecs from the Milky Way and is twice as small in size as the latter, and at least 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, coupled with a few dozen more dwarf galaxies, are part of the so-called Local Group, which is part of Virgo Superclusters- a huge stellar formation, the size of which is 200 million light years.

The Milky Way, the Andromeda Nebula and the Triangulum Galaxy have a lot in common. 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 disk 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 to the cluster 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 black hole of the Milky Way corresponds to more than three million masses of the Sun.

Black holes- one of the most impenetrable mysteries of the universe. Of course, they are watched, they are 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 space body that is in the zone of influence of one of them ( event threshold) will be immediately "swallowed" by this terrible universal monster. What will be the fate of the "unfortunate" - is unknown. In a word, it is easy to get into a black hole, but it is impossible to get out of it.

A lot of black holes are scattered across the expanses of the Cosmos, some of them have a mass many times greater than the mass of a black hole in the center of the Milky Way. But this does not at all mean that the monster “native” to the solar system is more harmless than its larger counterparts. It is also voracious and bloodthirsty, and is a compact (12.5 light-hours in diameter) and powerful source of X-rays.

The name of this mysterious object Sagittarius A. Its mass has already been named - more than 3 million masses of the Sun, and the gravitational trap (threshold of events) 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 the border of his bloodthirstiness and deceit lies 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 nutrition. This is an S2 star. It revolves around the black hole in a very compact orbit - a complete revolution is only 15.6 years. Maximum removal of S2 from scary monster lies within 5 light days, and the minimum is only 17 light hours.

Under the influence of the tidal forces of a black hole, part of its substance is torn off from a star doomed to be slaughtered and flies with great speed towards this terrible cosmic monster. As it approaches, the substance passes into a state of incandescent plasma and, radiating a farewell bright radiance, disappears forever in an 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 the stars, planets, interstellar dust and gas clouds to its more powerful counterpart. All this also turns into plasma, emits bright light and disappears into nowhere.

However, not all scientists, despite such a convincing 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 a huge density and bursts from within the surface compressing it with incredible force. Such education is called gravastar is a gravitational star.

Under this model, they try to fit the entire Universe, 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 release light from under an absolutely black shell. Maybe gravastors are other dimensions or parallel worlds? A concrete answer to this question will not be found for a very, very long time.

But not only the presence or absence of black holes occupies the minds of space explorers. Much more interesting and exciting are reflections on the existence of intelligent life in other star systems of the Universe.

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

The most reasonable assumption is that Earth-like life can arise on a planet that revolves around a star of the same class as the Sun. There is such a star in the sky, moreover, it is located in the star system closest to the earth's body. This is Alpha Centauri A, located in the constellation Centaurus. From the ground, 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 to you. But the desired does not always coincide with the actual. Finding signs of an extraterrestrial civilization, even at a distance of some 4-6 light years, is a rather difficult task with the current advances in technology. Therefore, it is premature to talk about the existence of any mind in the constellation Centaurus.

Nowadays, it is only possible to send radio signals into space, hoping that someone unknown will respond to the call of human intelligence. The most powerful radio stations of the world since the first half of the 20th century have been persistently and non-stop engaged in such activities. As a result, the level of radio emission of 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 smallness wears away a stone. If somewhere far, far away in the Cosmos there is a highly developed intelligent life, then, in any case, it must sometime turn its attention to the increased radiation background in the depths of the Milky Way galaxy, and to the radio signals coming from there. Such an interesting phenomenon cannot leave indifferent the inquisitive minds of aliens.

Accordingly, an active search for signals from the Cosmos has been established. But the dark abyss is silent, which indicates that there is most likely no sentient beings, ready to make contact with the inhabitants of planet Earth, or else their technical development is at a very primitive level. True, another thought arises, which suggests that a highly developed civilization, or civilizations, exists, but sends some other signals to the expanses of the Galaxy, which cannot be caught by terrestrial technical means.

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

It may turn out that the signal received by earthlings from space will turn out to be the voice of a long-disappeared extraterrestrial civilization that lived at a time when neither the solar system nor the Milky Way existed yet. The response message from the Earth will get to the aliens, who were not even in the project at the time when it was sent.

Well, you need to take into account the laws harsh reality. In any case, the search for intelligence in distant galactic worlds cannot be stopped. Unlucky current generations, lucky future ones. Hope in this case will never die, and perseverance and perseverance will undoubtedly pay off handsomely.

But it seems quite real and close to the development of galactic space. Already in the next century, fast and graceful will fly to the nearest constellations spaceships. The astronauts on their sides will observe through the windows not the planet Earth, but the entire solar system. She will be seen by them in the form of a distant, bright star. But it will not be the cold soulless brilliance of one of the countless suns of the Galaxy, but the native radiance of the Sun, near which mother earth will rotate as an invisible, soul-warming speck.

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, a rather boring and tedious task, like, for example, a trip in a subway car from one end of Moscow to another.

We are used to the fact that the Milky Way is a cluster of stars in the sky, according to which our ancestors navigated. But in fact, this is more than ordinary night luminaries - this is a huge and unexplored world.

This article is intended for persons over 18 years of age.

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The structure of the Milky Way galaxy

Sometimes it seems incredible how dynamic space science is developing. It is hard to imagine, but 4 centuries ago, even the statement that the Earth revolves around the Sun caused condemnation and rejection in society. Judgments about these and other cosmic phenomena could lead not only to imprisonment, but also to death. Fortunately, times have changed, and the study of the Universe has long been a priority in science. Particularly important in this regard is the study of the Milky Way - a galaxy of thousands of stars, one of which is our Sun.

The study of the structure of the galaxy and its development helps to answer the main questions that have interested humanity since the beginning of time. These are such sacramental mysteries about how the solar system arose, what factors contributed to the emergence of life on Earth, and whether life exists on other planets.

The fact that the Milky Way galaxy is a huge arm of an infinite star system became known relatively recently - a little more than half a century ago. The structure of our galaxy is similar to a colossal spiral in which our solar system is located somewhere on the periphery. From the side, it looks like a giant magnifying glass with a double-sided convex center with a crown.

What is the Milky Way galaxy? These are billions of stars and planets, which are interconnected by a certain algorithm for the structure of the Universe. In addition to stars, the Milky Way contains interstellar gas, galactic dust, and stellar globular clusters.

The disk of our galaxy constantly revolves around the central part, which is located in the constellation Sagittarius. It takes 220 million years for the Milky Way to make one complete revolution around its axis (and this despite the fact that the rotation occurs at a speed of 250 kilometers per second). Thus, all the stars of our galaxy move in unison over the years and our solar system along with them. What makes them revolve around the nucleus at a truly frantic speed? Scientists suggest that both the colossal weight of the center and the almost incomprehensible amount of energy (it can exceed the size of 150 million suns).

Why don't we see either spirals or a giant core, why don't we feel this universal rotation? The fact is that we are in the sleeve of this spiral Universe, and the frantic rhythm of its life is perceived by us everyday.

Of course, there will be skeptics who will deny such a structure of our galaxy, arguing that there is no (and cannot be) an exact picture of the galactic disk. The fact is that the Universe is by no means limited to the Milky Way galaxy and there are a lot of such formations in space. They are very similar to our galaxy in structure - these are the same disks with a center around which the stars revolve. That is, outside of our Milky Way, there are billions of systems similar to the Sun.

The nearest galaxy to us is the Large and Small Magellanic Clouds. They can be seen almost with the naked eye in the Southern Hemisphere. These two small luminous points, similar to clouds, were first described by the great traveler, on whose behalf the names of space objects originated. The diameter of the Magellanic Clouds is relatively small - it is less than half the Milky Way. And there are much fewer star systems in the Clouds.

Whether business Nebula Andromeda. This is another spiral-shaped galaxy that is very similar in appearance and composition to the Milky Way. Its dimensions are amazing - according to the most conservative estimates, it is three times larger than our Way. And the number of such gigantic galaxies in the Universe has long exceeded a billion - this is only what we can see at this stage in the development of astronomy. It is possible that in a few years we will become aware of another, previously unnoticed galaxy.

Characteristics of the Milky Way

As mentioned earlier, the Milky Way is a cluster of millions of stars with their own systems, similar to the Sun. How many planets there are in our galaxy is a real mystery, over the solution of which more than one generation of astronomers has been struggling. Although, to be honest, they are more concerned about another question - what is the probability that within our galaxy there is a star system whose characteristics are similar to ours? Scientists are especially interested in stars that have similar rotation speeds and technical characteristics to the Sun, as well as occupying our place on the scale of the galaxy. This is because on planets that have the approximate age and conditions of our Earth, there is a high probability of the presence of intelligent life.

Unfortunately, attempts by scientists to find at least something similar to the solar system in the arms of the galaxy were unsuccessful. And this is perhaps for the best. It is still unknown who or what may be waiting for us in an unfamiliar constellation.

Black Hole - the killer of planets or the creator of galaxies?

At the end of its life, a star sheds its gas envelope, and its core begins to shrink very quickly. Provided that the mass of the star is large enough (1.4 times more than the Sun), a Black Hole is formed in its place. This is an object with a critical speed that no object can overcome. As a result, what falls into the Black Hole disappears in it forever. That is, in fact, this cosmic element is a one-way ticket. Any object that gets close enough to the Hole will disappear forever.

Sad, isn't it? But there is also a positive point in the Black Hole - thanks to it, various space objects are gradually pulled up and new galaxies are formed. It turns out that the core of each of the known star systems is a Black Hole.

Why is our galaxy called the Milky Way?

Each nation has its own legends about how the visible part of the Milky Way was formed. For example, the ancient Greeks believed that it was formed from the spilled milk of the goddess Hera. But in Mesopotamia there was a legend about a river from the same drink. Thus, many peoples associated a large cluster of stars with milk, thanks to which our galaxy got its name.

How many stars are in the Milky Way?

It is quite difficult to accurately calculate the number of stars in our galaxy, because they say that there are more than 200 billion of them. As you understand, to study them all with modern development science is very problematic, so scientists turn their attention only to the most interesting representatives of these space objects. Take at least an alpha star from the constellation Carina (Kiel). This is a supergiant star for a long time bore the title of the largest and brightest.

The sun is also one of the stars in the Milky Way, which, however, does not have any outstanding characteristics. This is a small yellow dwarf, which became famous only for the fact that for millions of years it has been the source of life on our planet.

Astronomers from all over the world have long compiled lists of stars that have an outstanding mass or brightness. But this does not mean at all that each of them received its own name. Usually the names of stars consist of letters, numbers and the names of the constellations to which they refer. So, the brightest star in the Milky Way is indicated on astronomical maps as R136a1, and R136 is nothing more than the name of the nebula from which it comes from. This star has an indescribable power that cannot be compared with anything. R136a1 shines 8.7 million times brighter than our Sun, and therefore it is very difficult to imagine at least some life near it.

But colossal power does not mean at all that the R136a1 has impressive dimensions. The list of the largest stars is headed by UY Shield, which is 1.7 thousand times the size of our star. That is, if instead of the Sun there was this star, then it would take up the entire place from the center of our system to Saturn.

No matter how big and powerful these stars would be, the total number of their mass does not compare with the mass of the Black Hole, which is located in the center of the galaxy. It is her colossal energy that holds the Milky Way, forcing it to move in a certain order.

Our galaxy is not just a scattering of stars in the night sky. This is a huge system that consists of hundreds of billions of stars, among which is our Sun.

The starry sky has attracted the eyes of people since ancient times. The best minds of all peoples tried to comprehend our place in the Universe, to imagine and justify its structure. Scientific progress made it possible to move in the study of the vast expanses of space from romantic and religious constructions to logically verified theories based on numerous factual material. Now any schoolchild has an idea of ​​what our Galaxy looks like according to the latest research, who, why and when gave it such a poetic name and what its supposed future is.

origin of name

The expression "the Milky Way galaxy" is, in fact, a tautology. Galactikos roughly translated from ancient Greek means "milk". So the inhabitants of the Peloponnese called the cluster of stars in the night sky, attributing its origin to the hot-tempered Hera: the goddess did not want to feed Hercules, illegitimate son Zeus, and in anger splashed breast milk. Drops and formed a star track, visible on clear nights. Centuries later, scientists discovered that the observed luminaries are only an insignificant part of the existing celestial bodies. They gave the name of the Galaxy or the Milky Way system to the space of the Universe, in which our planet is also located. After confirming the assumption of the existence of other similar formations in space, the first term became universal for them.

Inside view

Scientific knowledge about the structure of the part of the universe, including the solar system, took little from the ancient Greeks. The understanding of what our Galaxy looks like has evolved from the spherical universe of Aristotle to modern theories, in which there is a place for black holes and dark matter.

The fact that the Earth is an element of the Milky Way system imposes certain restrictions on those who are trying to figure out what shape our galaxy has. An unequivocal answer to this question requires a view from the side, and at a great distance from the object of observation. Now science is deprived of such an opportunity. A kind of substitute for an outside observer is the collection of data on the structure of the Galaxy and their correlation with the parameters of other space systems available for study.

The collected information allows us to say with confidence that our Galaxy has the shape of a disk with a thickening (bulge) in the middle and spiral arms diverging from the center. The latter contain the brightest stars in the system. The disk is over 100,000 light-years across.

Structure

The center of the Galaxy is hidden by interstellar dust, which makes it difficult to study the system. The methods of radio astronomy help to cope with the problem. Waves of a certain length easily overcome any obstacles and allow you to get such a desired image. Our Galaxy, according to the data obtained, has an inhomogeneous structure.

It is conditionally possible to distinguish two elements connected with each other: the halo and the disk itself. The first subsystem has the following characteristics:

• in shape it is a sphere;

• its center is considered to be the bulge;
• the highest concentration of stars in the halo is characteristic of its middle part, with approaching the edges, the density strongly decreases;
• the rotation of this zone of the galaxy is rather slow;
• the halo mostly contains old stars with a relatively small mass;
• a significant space of the subsystem is filled with dark matter.

The galactic disk in terms of the density of stars greatly exceeds the halo. In the sleeves there are young and even just emerging

Center and core

The "heart" of the Milky Way is located in Without studying it, it is difficult to fully understand what our Galaxy is like. The name "core" in scientific papers either refers only to the central region only a few parsecs in diameter, or includes the bulge and gas ring, which is considered the birthplace of stars. In what follows, the first version of the term will be used.

Visible light struggles to penetrate the center of the Milky Way as it collides with a lot of cosmic dust that obscures what our Galaxy looks like. Photos and images taken in the infrared range greatly expand the knowledge of astronomers about the nucleus.

Data on the features of radiation in the central part of the Galaxy led scientists to the idea that there is a black hole in the core of the nucleus. Its mass is more than 2.5 million times the mass of the Sun. Around this object, according to researchers, another, but less impressive in its parameters, black hole rotates. Modern knowledge about the features of the structure of the cosmos suggest that such objects are located in the central part of most galaxies.

Light and darkness

The joint influence of black holes on the movement of stars makes its own adjustments to how our Galaxy looks: it leads to specific changes in orbits that are not typical for cosmic bodies, for example, near the solar system. The study of these trajectories and the relationship between the velocities of motion and the distance from the center of the Galaxy formed the basis of the currently actively developing theory of dark matter. Its nature is still shrouded in mystery. The presence of dark matter, presumably constituting the vast majority of all matter in the Universe, is registered only by the effect of gravity on orbits.

If we dispel all the cosmic dust that the core hides from us, a striking picture opens up. Despite the concentration of dark matter, this part of the universe is full of light emitted by huge amount stars. There are hundreds of times more of them per unit of space than near the Sun. Approximately ten billion of them form a galactic bar, also called a bar, of an unusual shape.

space nut

The study of the center of the system in the long-wavelength range made it possible to obtain a detailed infrared image. Our Galaxy, as it turned out, in the core has a structure resembling a peanut in a shell. This "nut" is the jumper, which includes more than 20 million red giants (bright, but less hot stars).

Spiral arms of the Milky Way diverge from the ends of the bar.

The work associated with the discovery of a “peanut” at the center of a star system not only shed light on what our Galaxy is like in structure, but also helped to understand how it developed. Initially, in the space of space there was an ordinary disk, in which a jumper formed over time. Under the influence of internal processes, the bar changed its shape and began to look like a walnut.

Our house on the space map

Active activity occurs both in the bar and in the spiral arms that our Galaxy has. They were named after the constellations where branches of the branches were discovered: the arms of Perseus, Cygnus, Centaurus, Sagittarius and Orion. Near the latter (at a distance of at least 28 thousand light years from the core) is the solar system. This area has certain characteristics, according to experts, that made possible the emergence of life on Earth.

The galaxy and our solar system rotate with it. The patterns of motion of the individual components do not coincide in this case. stars are sometimes part of the spiral branches, then separated from them. Only the luminaries lying on the boundary of the corotation circle do not make such "journeys". These include the Sun, protected from the powerful processes that are constantly taking place in the arms. Even a slight shift would negate all other advantages for the development of organisms on our planet.

Sky in diamonds

The sun is just one of many similar bodies that fill our galaxy. Stars, single or grouped, total more than 400 billion according to the latest data. The closest Proxima Centauri to us is part of a three-star system, along with the slightly more distant Alpha Centauri A and Alpha Centauri B. The brightest point in the night sky, Sirius A, is located in Its luminosity, according to various sources, exceeds the solar one by 17-23 times. Sirius is also not alone, he is accompanied by a satellite bearing a similar name, but labeled B.

Children often begin to get acquainted with what our Galaxy looks like by searching the sky for the North Star or Alpha Ursa Minor. It owes its popularity to its position above the North Pole of the Earth. In terms of luminosity, Polaris significantly exceeds Sirius (almost two thousand times brighter than the Sun), but it cannot challenge the rights of Alpha Big Dog for the title of the brightest because of the distance from Earth (estimated from 300 to 465 light years).

Types of luminaries

Stars differ not only in luminosity and distance from the observer. A certain value is assigned to each (the corresponding parameter of the Sun is taken as a unit), the degree of surface heating, and color.

The most impressive sizes are supergiants. Neutron stars have the highest concentration of matter per unit volume. The color characteristic is inextricably linked with temperature:

• reds are the coldest;
• heating the surface to 6,000º, like that of the Sun, gives rise to a yellow tint;
• white and blue luminaries have a temperature of more than 10,000º.

It can change and reach a maximum shortly before its collapse. Supernova explosions make a huge contribution to understanding what our Galaxy looks like. The photographs of this process taken by telescopes are amazing.
The data collected on their basis helped to reconstruct the process that led to the flare and to predict the fate of a number of cosmic bodies.

Future of the Milky Way

Our Galaxy and other galaxies are constantly in motion and interacting. Astronomers have found that the Milky Way has repeatedly swallowed up its neighbors. Similar processes are expected in the future. Over time, it will include the Magellanic Cloud and a number of dwarf systems. The most impressive event is expected in 3-5 billion years. This will be a collision with the only neighbor that is visible from Earth to the naked eye. As a result, the Milky Way will become an elliptical galaxy.

The endless expanses of space are amazing. It is difficult for the layman to realize the magnitude of not only the Milky Way or the entire Universe, but even the Earth. However, thanks to the achievements of science, we can imagine at least approximately what a part of the grandiose world we are.

The Milky Way Galaxy contains the solar system, the Earth and all the stars that are visible to the naked eye. Together with the Triangulum, Andromeda and dwarf galaxies and satellites, it forms the Local Group of galaxies, which is part of the Virgo Supercluster.

By ancient legend When Zeus decided to make his son Hercules immortal, he placed him on the breast of his wife Hera to drink milk. But the wife woke up and, seeing that she was feeding a step-child, pushed him away. A stream of milk splashed and turned into the Milky Way. In the Soviet astronomical school, it was simply called "the Milky Way system" or "our Galaxy." Outside of Western culture, there are many names for this galaxy. The word "milky" is replaced by other epithets. The galaxy consists of about 200 billion stars. Most of them are located in the form of a disk. Most of the mass of the Milky Way is contained in a halo of dark matter.

In the 1980s, scientists put forward the view that the Milky Way is a barred spiral galaxy. The hypothesis was confirmed in 2005 using the Spitzer telescope. It turned out that the central bar of the galaxy is larger than previously thought. The diameter of the galactic disk is approximately 100 thousand light years. Compared to the halo, it spins much faster. At different distances from the center, its speed is not the same. Studies of the disk's rotation helped to estimate its mass, which is 150 billion more than the mass of the Sun. Near the plane of the disk, young star clusters and stars are collected, which form a flat component. Scientists suggest that many galaxies have black holes in their core.

A large number of stars are collected in the central regions of the Milky Way Galaxy. The distance between them is much smaller than in the vicinity of the Sun. The length of the galactic bridge, according to scientists, is 27 thousand light years. It passes through the center of the Milky Way at an angle of 44 degrees ± 10 degrees to the line between the center of the galaxy and the Sun. Its component is predominantly red stars. The jumper is surrounded by a ring, which is called the "Ring of 5 kiloparsecs". It contains a large amount of molecular hydrogen. It is also an active star-forming region in the galaxy. Viewed from the Andromeda galaxy, the bar of the Milky Way would be its brightest part.

Since the Milky Way Galaxy is considered a spiral galaxy, it has spiral arms that lie in the plane of the disk. Around the disk is a spherical corona. The solar system is located 8.5 thousand parsecs from the center of the galaxy. According to recent observations, we can say that our Galaxy has 2 arms and a couple more arms in the inner part. They transform into a four-arm structure, which is observed in the neutral hydrogen line.

The halo of the galaxy has a spherical shape, which extends beyond the Milky Way by 5–10 thousand light years. Its temperature is approximately 5 * 10 5 K. The halo consists of old, low-mass, dim stars. They can be found in the form of globular clusters, and one by one. The bulk of the galaxy is dark matter, forming a halo of dark matter. Its mass is approximately 600–3000 billion solar masses. Star clusters and halo stars move around the galactic center in elongated orbits. The halo rotates very slowly.

History of the discovery of the Milky Way Galaxy

Many celestial bodies are combined into a variety of rotating systems. Thus, the Moon revolves around the Earth, and the satellites of the major planets form their systems. The earth and other planets revolve around the sun. Scientists had a completely logical question: is the Sun included in an even larger system?

For the first time, William Herschel tried to answer this question. He calculated the number of stars in different corners the sky and found out what's in the sky big circle- the galactic equator, dividing the sky into two parts. Here the number of stars was the greatest. The closer this or that part of the sky is located to this circle, the more stars there are on it. Ultimately, it was discovered that the Milky Way is located at the equator of the galaxy. Herschel came to the conclusion that all the stars form one star system.

Initially it was believed that everything in the universe is part of our galaxy. But even Kant argued that some nebulae can be separate galaxies, like the Milky Way. Only when Edwin Hubble measured the distance to some spiral nebulae and showed that they cannot be part of the Galaxy, Kant's hypothesis was proved.

Future of the Galaxy

In the future, collisions of our Galaxy with others, including Andromeda, are possible. But there are no concrete predictions yet. It is believed that in 4 billion years the Milky Way will be swallowed up by the Small and Large Magellanic Clouds, and in 5 billion years it will be swallowed up by the Andromeda Nebula.

Planets of the Milky Way

Despite the fact that stars are constantly born and die, their number is clearly counted. Scientists believe that at least one planet revolves around every star. This means that there are from 100 to 200 billion planets in the Universe. The scientists who worked on this statement studied "red dwarf" stars. They are smaller than the Sun and make up 75% of all stars in the Milky Way Galaxy. Particular attention was paid to the star Kepler-32, which "sheltered" 5 planets.

Planets are much harder to spot than stars because they don't emit light. We can confidently say about the existence of a planet only when it obscures the light of a star.

There are also planets that are similar to our Earth, but there are not so many of them. There are many types of planets, for example, pulsar planets, gas giants, brown dwarfs... If a planet is composed of rocks, it will bear little resemblance to Earth.

Recent studies claim that there are between 11 and 40 billion Earth-like planets in the galaxy. Scientists examined 42 sun-like stars and found 603 exoplanets, 10 of which matched the search criteria. It has been proven that all planets similar to Earth can maintain the right temperature for the existence of liquid water, which, in turn, will help the emergence of life.

Stars have been discovered near the outer edge of the Milky Way that move in a special way. They drift off the edge. Scientists suggest that this is all that is left of the galaxies that were swallowed up by the Milky Way. Their encounter happened many years ago.

satellite galaxies

As we have said, the Milky Way Galaxy is a spiral galaxy. It is an irregularly shaped spiral. For years scientists could not find an explanation for the bulge of the galaxy. Now everyone has come to the conclusion that this is due to satellite galaxies and dark matter. They are very small and cannot affect the Milky Way. But as dark matter moves through the Magellanic Clouds, waves are created. They also influence gravitational attraction. Under this action, hydrogen escapes from the galactic center. Clouds revolve around the Milky Way.

Although the Milky Way is called unique in many ways, it is not a rarity. If we take into account the fact that there are approximately 170 billion galaxies in the field of view, we can assert the existence of galaxies similar to ours. In 2012, astronomers found exact copy Milky way. It even has two satellites that correspond to the Magellanic Clouds. By the way, they assume that in a couple of billion years they will dissolve. Finding such a galaxy was an incredible stroke of luck. Named NGC 1073, it looks so much like the Milky Way that astronomers study it to learn more about our galaxy.

Galactic year

An Earth year is the time it takes a planet to complete one revolution around the sun. In the same way, the solar system revolves around the black hole, which is located in the center of the galaxy. Its full rotation is 250 million years. When describing the solar system, they rarely mention that it moves in outer space, like everything else in the world. The speed of its movement is 792,000 km per hour relative to the center of the Milky Way Galaxy. If we compare, then we, moving at a similar speed, could go around the whole world in 3 minutes. A galactic year is the time it takes for the Sun to complete one revolution around the Milky Way. At last count, the sun lived for 18 galactic years.