Universe galaxy milky way. Dangerous neighbor

Milky Way (MP) Is a huge gravitationally bound system containing at least 200 billion stars, thousands of giant clouds of gas and dust, clusters and nebulae. Belongs to the class of barred spiral galaxies. The MP is compressed in the plane and in profile is similar to a "flying saucer".

The Milky Way with the Andromeda Galaxy (M31), the Triangle Galaxy (M33), and more than 40 dwarf satellite galaxies - our own and Andromeda - all together form the Local Group of Galaxies, which is part of the Local Supercluster (Virgo Supercluster).

Our Galaxy has the following structure: a core of billions of stars with a black hole in the center; a disk of stars, gas and dust 100,000 light-years in diameter and 1,000 light-years thick; in the middle of the disk, a bulge 3,000 light-years thick. years old; sleeves; a spherical halo (corona) containing dwarf galaxies, globular star clusters, individual stars, groups of stars, dust and gas.

The central regions of the Galaxy are characterized by a strong concentration of stars: each cubic parsec contains many thousands of them near the center. The distances between the stars are tens and hundreds of times less than in the vicinity of the Sun.

The galaxy rotates, but not evenly with the entire disk. With approaching the center, the angular velocity of rotation of stars around the center of the Galaxy increases.

In the galactic plane, in addition to the increased concentration of stars, there is also an increased concentration of dust and gas. Between the center of the Galaxy and the spiral arms (branches) there is a gas ring - a mixture of gas and dust that radiates strongly in the radio and infrared range. This ring is about 6 thousand light years wide. It is located in an area between 10,000 and 16,000 light years from the center. The ring of gas contains billions of solar masses of gas and dust and is the site of active star formation.

The Galaxy has a corona that contains globular clusters and dwarf galaxies (Large and Small Magellanic Clouds and other clusters). The galactic corona also contains stars and groups of stars. Some of these groups interact with globular clusters and dwarf galaxies.

The plane of the Galaxy and the plane of the Solar system do not coincide, but are at an angle to each other, and the solar planetary system revolves around the center of the Galaxy in about 180-220 million Earth years - this is how much one galactic year lasts for us.

In the vicinity of the Sun, it is possible to track sections of two spiral arms, which are approximately 3 thousand light years distant from us. According to the constellations where these areas are observed, they were named the Sagittarius arm and the Perseus arm. The sun is located almost midway between these spiral branches. But relatively close to us (by galactic standards), in the constellation Orion, there is another, not very clearly defined arm - the Orion arm, which is considered an offshoot of one of the main spiral arms of the Galaxy.

The speed of rotation of the Sun around the center of the Galaxy almost coincides with the speed of the compaction wave forming the spiral arm. This situation is atypical for the Galaxy as a whole: the spiral arms rotate at a constant angular velocity, like spokes in wheels, and the movement of stars occurs with a different pattern, therefore, almost the entire stellar population of the disk either gets inside the spiral arms or falls out of them. The only place where the speeds of stars and spiral arms coincide is the so-called corotation circle, and it is on this circle that the Sun is located.

For the Earth, this circumstance is extremely important, since violent processes occur in the spiral arms, forming powerful radiation, destructive for all living things. And no atmosphere could protect against him. But our planet exists in a relatively quiet place in the Galaxy and has not been exposed to these cosmic cataclysms for hundreds of millions (or even billions) years. Perhaps this is why life on Earth was able to be born and survive.

Analysis of the rotation of the Galaxy has shown that it contains large masses of non-luminous (non-radiating) matter, called "hidden mass" or "dark halo". The mass of the Galaxy, taking into account this hidden mass, is estimated at about 10 trillion solar masses. According to one hypothesis, some of the hidden mass may be contained in brown dwarfs, in gas giant planets that occupy an intermediate position between stars and planets, and in dense and cold molecular clouds that have a low temperature and are inaccessible to conventional observations. In addition, in our and other galaxies there are many bodies the size of the planet, which are not included in any of the circumstellar systems and therefore are not visible through telescopes. Some of the hidden mass of galaxies may belong to "extinct" stars. According to another hypothesis, galactic space (vacuum) also contributes to the amount of dark matter. Latent mass is not only in our Galaxy, it is in all galaxies.

The problem of dark matter in astrophysics arose when it turned out that the rotation of galaxies (including our own Milky Way) could not be correctly described if we consider only the ordinary visible (luminous) matter they contain. All the stars of the Galaxy in this case would have to scatter and scatter in the vastness of the Universe. In order for this not to happen (and this does not happen), the presence of additional invisible matter with a large mass is necessary. The action of this invisible mass is manifested exclusively in the gravitational interaction with visible matter. At the same time, the amount of invisible matter should be approximately six times the amount of visible matter (information about this was published in the scientific journal Astrophysical Journal Letters). The nature of dark matter, as well as dark energy, the presence of which is assumed in the observable universe, remains unclear.

Our Galaxy. Mysteries of the Milky Way

To some extent, we know more about distant stellar systems than about our own galaxy, the Milky Way. Its structure is more difficult to study than the structure of any other galaxies, because you have to study it from the inside, and much is not so easy to see. Interstellar dust clouds absorb light from a myriad of distant stars.

Only with the development of radio astronomy and the advent of infrared telescopes have scientists been 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 roughly estimated. The latest electronic guides list 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 from the University of Wisconsin published the results of processing about 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 sleeves, they are only narrow lateral branches. So, the Milky Way is a spiral galaxy with two arms. It should be noted that most of the 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 the conference of the American Astronomical Society. "We are refining our understanding of the Galaxy in the same way as centuries ago, when the discoverers traveled around the globe, they refined and rethought previous ideas about what the Earth looks like."

Since the early 90s of the XX century, observations carried out in the infrared range have been changing our knowledge of the structure of the Milky Way more and more, because infrared telescopes make it possible to look through clouds of gas and dust 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. In the beginning, 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 develop - slowly or, on the contrary, very quickly? How was she saturated with heavy elements? How did the shape of the Milky Way and its chemical composition change over billions of years? Scientists have yet to provide detailed answers to these questions.

Our Galaxy is about 100,000 light years long, 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 large or small by cosmic standards? For comparison, the Andromeda Nebula, the closest large galaxy to us, is approximately 150,000 light years across.

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

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 the little sister of the 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 gravitational force is also higher, which means that the likelihood of its collision with other galaxies in our vicinity increases.

Our Galaxy is surrounded by a globular halo that reaches 165,000 light years across. Astronomers sometimes refer to the halo as the "galactic atmosphere." It contains approximately 150 globular clusters, as well as a small number of ancient stars. The rest of the halo space is filled with rarefied gas, as well as dark matter. The mass of the latter is estimated at about a trillion solar masses.

The spiral arms of the Milky Way contain enormous amounts of hydrogen. This is where stars continue to be born. Over time, young stars leave the arms of galaxies and "migrate" to the galactic disk. However, the most massive and brightest stars live for a rather 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 clouds of gas and dust, beyond which nothing can be seen. Only since the 1950s, using the means of radio astronomy, have scientists been able to gradually see what lies there. In this part of the Galaxy, a powerful radio source was discovered, called Sagittarius A. Observations showed that a mass is concentrated here, exceeding the mass of the Sun by several million times. The most acceptable explanation for this fact is possible only one thing: in the center of our Galaxy is located.

Now, for some reason, she took a break for herself and does not show much activity. The influx of matter here is very scarce. Maybe over time, the black hole will have an appetite. Then it will again begin to absorb the veil of gas and dust that surrounds it, and the Milky Way will join the list of active galaxies. It is possible that before this in the center of the Galaxy stars will begin to vigorously appear. Such processes are likely to be repeated regularly.

2010 - American astronomers using the Fermi Space Telescope, designed to observe the sources of gamma radiation, discovered two mysterious structures in our Galaxy - two huge bubbles emitting gamma radiation. Each of them averages 25,000 light years in diameter. They scatter from the center of the Galaxy in the north and south directions. Maybe we are talking about the streams of particles that were once emitted by a black hole in the middle of the Galaxy. Other researchers believe that we are talking about gas clouds that exploded when stars were born.

There are several dwarf galaxies around the Milky Way. The most famous of these are the Large and Small Magellanic Clouds, which are connected to the Milky Way by a kind of hydrogen bridge, a huge plume of gas that stretches behind these galaxies. It was named "Magellanic Stream". It spans about 300,000 light years. Our Galaxy constantly engulfs the nearest dwarf galaxies, in particular, the Sagitarius galaxy, which is located 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 to form a larger elliptical galaxy, which has already been named "Milky Honey".

The 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 (named after the initial letters of their last names). According to her, a homogeneous cloud of gas once slowly revolved in place of the Milky Way. It resembled a sphere and was approximately 300,000 light years across, and consisted primarily of hydrogen and helium. Under the influence of gravity, the protogalaxy shrank and became flat; at the same time, its rotation accelerated noticeably.

For almost two decades, this model suited scientists. But the new observations showed that the Milky Way could not have arisen the way theorists dictated it.

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

Globular clusters have been found in both the galactic disk and the halo that are younger than the ELS model suggests. Obviously, they are swallowed up by our later Galaxy.

Many stars in the halo rotate in a different direction than the Milky Way. Perhaps they, too, were once outside the Galaxy, but then they were drawn into this "star vortex" - like an accidental 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 the "SZ model". Now the history of the Galaxy has become much more complicated. Not so long ago, in the minds of astronomers, her youth was described as simply as, in the opinion of physicists, rectilinear translational motion. The mechanics of what was happening was clearly visible: there was a homogeneous cloud; it consisted only of evenly spreading gas. Nothing, by its presence, complicated the calculations of theorists.

Now, instead of one huge cloud in the visions of scientists, several small, fancifully scattered clouds appeared at once. Among them were the stars; however, they were located only in the halo. Everything inside the halo was seething: the clouds collided; the gas masses were mixed and compacted. Over time, a galactic disk was formed from this mixture. New stars began to appear in it. But this model was later 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. Already after Searle and Zinn compiled their model, it turned out that the halo rotates too slowly to form a galactic disk. 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 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 generally accepted 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 disintegrate, ”notes the German astronomer Andreas Burkert, the author of a new model of the birth of the Galaxy.

Dark halos became the embryos - nuclei - of future galaxies. Gas accumulated around them under the influence of gravity. A homogeneous collapse occurred, as the ELS model describes it. Already 500-1000 million years after the Big Bang, the gas clusters that surrounded the dark halos became "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 the universe, whose age is more than 12 billion years.

There were many very massive stars in the 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, not such stars were born in the galactic disk as in the halo - they contained hundreds of times more metals. In addition, these explosions generated powerful galactic vortices that heated the gas and swept it out of the protogalaxies. The separation of gas masses and dark matter has occurred. 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 were increasingly colliding with each other. Moreover, the protogalaxies stretched out or disintegrated. These catastrophes are reminiscent of the chains of stars that have been preserved in the halo of the Milky Way since the days of "youth". By studying their location, it is possible to assess the events that took place in that era. Gradually, a vast sphere formed from these stars - the halo we see. As it cooled down, gas clouds penetrated into it. Their angular momentum was preserved, because they did not collapse 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. Bulge is composed of very old stars. It probably arose from the merger of the largest protogalaxies that held gas clouds for the longest time. Among it were neutron stars and tiny black holes - relics of exploding supernovae. They merged with each other, simultaneously absorbing gas streams. Perhaps this is how a 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 home Galaxy, impressive even by cosmic standards, was formed after a series of impacts and mergers - after a series of cosmic catastrophes. Traces of those old events can still be found today.

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

In addition, the Milky Way attracts huge masses of gas. 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 dwarf galaxies closest to us - Fornax, Karina and, probably, Sextans, and then merge with the Andromeda nebula. Around the Milky Way - this insatiable "star cannibal" - will become even deserted.

Divided into social groups, our Milky Way galaxy will belong to the robust "middle class". So, it belongs to the most widespread type of galaxies, but at the same time it is not average in size or mass. There are more galaxies that are smaller than the Milky Way than those that are larger. Our "star island" also has at least 14 satellites - other dwarf galaxies. They are doomed to circle around the Milky Way until they are absorbed by it, or fly away from an intergalactic collision. Well, so far this is the only place where life probably exists - that is, you and me.

But the Milky Way remains the most mysterious galaxy in the Universe: being on the very edge of the "star island", we see only a part of its billions of stars. And galaxies are completely invisible - it is covered by dense arms of stars, gas and dust. The facts and secrets of the Milky Way will be discussed today.

The Milky Way Galaxy is very majestic, beautiful. This huge world is our Motherland, our solar system. All stars and other objects that are visible to the naked eye in the night sky are our galaxy. Although there are some objects that are located in the Andromeda Nebula - a neighbor of our Milky Way.

Description of the Milky Way

The Milky Way Galaxy is huge, 100 thousand light years across, and, as you know, one light year is equal to 9460730472580 km. Our solar system is located from the center of the galaxy at a distance of 27,000 light years, in one of the arms, which is called the arm of Orion.

Our solar system revolves around the center of the Milky Way galaxy. This happens in the same way as the Earth revolves around the Sun. The solar system completes a full revolution in 200 million years.

Deformation

The Milky Way Galaxy looks like a disc with a bulge in the center. He's not in perfect shape. On the one hand, there is a bend to the north of the center of the galaxy, and on the other, it goes down, then turns to the right. Outwardly, such a deformation is somewhat reminiscent of a wave. The disc itself is deformed. This is due to the presence of the Small and Large Magellanic Clouds nearby. They rotate around the Milky Way very quickly - this was confirmed by the Hubble telescope. These two dwarf galaxies are often referred to as satellites of the Milky Way. The clouds create a gravitationally bound system that is very heavy and quite massive due to the heavy elements in the mass. It is assumed that they are pulling a rope between galaxies, creating vibrations. As a result, the Milky Way galaxy is deformed. The structure of our galaxy is special, it has a halo.

Scientists believe that in billions of years, the Milky Way will be swallowed up by the Magellanic Clouds, and after a while it will be swallowed up by Andromeda.

Halo

Wondering which galaxy is the Milky Way, scientists began to study it. They managed to find out that 90% of its mass consists of dark matter, which creates a mysterious halo. Everything that can be seen with the naked eye from Earth, namely that luminous matter, is about 10% of the galaxy.

Numerous studies have confirmed that the Milky Way has a halo. Scientists have made various models that take into account the invisible part and without it. After the experiments, the opinion was put forward that if there were no halo, then the speed of movement of the planets and other elements of the Milky Way would be less than now. Because of this feature, it was assumed that most of the components are composed of invisible mass or dark matter.

Number of stars

One of the most unique is the Milky Way galaxy. The structure of our galaxy is unusual, it contains more than 400 billion stars. About a fourth of them are large stars. Note: other galaxies have fewer stars. There are about ten billion stars in the Cloud, some others consist of a billion, and in the Milky Way there are more than 400 billion of various stars, and only a small part of the Earth is visible, about 3000. It is impossible to say exactly how many stars are in the Milky Way, because how the galaxy is constantly losing objects due to their transformation into supernovae.

Gases and dust

About 15% of the galaxy's constituent is dust and gases. Could it be because of them that our galaxy is called the Milky Way? Despite its enormous size, we can see about 6,000 light years ahead, while the galaxy is 120,000 light years across. It may be larger, but even the most powerful telescopes cannot see further. This is due to the accumulation of gas and dust.

The thickness of the dust blocks visible light, but infrared light passes through it, and scientists can create maps of the starry sky.

What came before

According to scientists, our galaxy has not always been like this. The Milky Way emerged from the merger of several other galaxies. This giant conquered other planets, areas, which had a strong impact on size and shape. Even now, planets are being captured by the Milky Way galaxy. An example of this is the objects of Canis Major, a dwarf galaxy located near our Milky Way. Dog stars are periodically added to our universe, and from ours they move to other galaxies, for example, there is an exchange of objects with the Sagittarius galaxy.

Milky Way View

Not a single scientist, astronomer can say exactly what our Milky Way looks like from above. This is due to the fact that Earth is located in the Milky Way galaxy 26,000 light years from the center. Due to this location, it is not possible to take pictures of the entire Milky Way. Therefore, any image of a galaxy is either images of other visible galaxies, or someone's fantasy. And we can only guess how it really looks. There is even a possibility that we now know as much about it as the ancient people who considered the Earth to be flat.

Center

The center of the Milky Way galaxy is called Sagittarius A * - a great source of radio waves, suggesting that there is a huge black hole in the heart. Its dimensions are estimated to be just over 22 million kilometers, and this is the hole itself.

All substances that try to get into the hole form a huge disk, almost 5 million times larger than our Sun. But even this pulling force does not prevent new stars from forming at the edge of the black hole.

Age

According to estimates of the composition of the Milky Way galaxy, it was possible to establish an estimated age of about 14 billion years. The oldest star is just over 13 billion years old. The age of a galaxy is calculated by determining the age of the oldest star and the phases preceding its formation. Based on the available data, scientists have suggested that our universe is about 13.6-13.8 billion years old.

First, the bulge of the Milky Way was formed, then its middle part, in the place of which a black hole subsequently formed. Three billion years later, a disk with arms appeared. It gradually changed, and only about ten billion years ago it began to look as it does now.

We are part of something more

All of the stars in the Milky Way galaxy are part of a larger galactic structure. We are part of the Virgo Supercluster. The nearest galaxies to the Milky Way, such as the Magellanic Cloud, Andromeda and other fifty galaxies, are one cluster, the Virgo Supercluster. A supercluster is a group of galaxies that covers a huge area. And this is only a small part of the stellar neighborhood.

The Virgo Supercluster contains more than a hundred cluster groups spread over 110 million light years in diameter. The Virgo cluster itself is a small part of the Laniakea supercluster, and it, in turn, is part of the Pisces-Cetus complex.

Rotation

Our Earth moves around the Sun, making a complete revolution in 1 year. Our Sun revolves in the Milky Way around the center of the galaxy. Our galaxy is moving in relation to a special radiation. The relic radiation is a convenient reference point that allows you to determine the speed of a variety of matters in the Universe. Studies have shown that our galaxy rotates at a speed of 600 kilometers per second.

Appearance of the name

The galaxy got its name from its special appearance, reminiscent of spilled milk in the night sky. The name was given to it in ancient Rome. Then she was called "expensive milk". Until now, it is called the Milky Way, associating the name with the appearance of the white stripe in the night sky, with spilled milk.

The galaxy has been mentioned since the era of Aristotle, who said that the Milky Way is the place where the celestial spheres are in contact with the earthly ones. Until the telescope was created, no one added anything to this opinion. And only from the seventeenth century people began to look at the world differently.

Our neighbours

For some reason, many people think that the nearest galaxy to the Milky Way is Andromeda. But this opinion is not entirely correct. The closest "neighbor" to us is the Canis Major galaxy, located inside the Milky Way. It is located at a distance of 25,000 light years from us, and 42,000 light years from the center. In fact, the Big Dog is closer to us than to the black hole in the center of the galaxy.

Before the discovery of Canis Major at a distance of 70 thousand light years, Sagittarius was considered the closest neighbor, and after that - the Large Magellanic Cloud. Unusual stars with a huge density class M were discovered in Pse.

According to the theory, the Milky Way absorbed Canis Major, along with all its stars, planets and other objects.

Collision of galaxies

Recently, more and more information has been encountered that the nearest galaxy to the Milky Way, the Andromeda Nebula, will engulf our universe. These two giants formed at about the same time - about 13.6 billion years ago. It is believed that these giants are able to unite galaxies, and due to the expansion of the Universe, they must move away from each other. But, contrary to all the rules, these objects are moving towards each other. The speed of movement is 200 kilometers per second. It is estimated that in 2-3 billion years Andromeda will collide with the Milky Way.

Astronomer J. Dubinsky created the collision model presented in this video:

The collision will not lead to a global catastrophe. And after a few billion years, a new system will form, with the usual galactic forms.

Lost galaxies

Scientists have conducted a large-scale study of the starry sky, covering about an eighth of it. As a result of the analysis of the star systems of the Milky Way galaxy, it was possible to find out that there are previously unknown streams of stars on the outskirts of our universe. This is all that remains of small galaxies that were once destroyed by gravity.

The telescope installed in Chile took a huge number of images that allowed scientists to assess the sky. The images estimate that our galaxy is surrounded by a dark matter halo, rarefied gas and scanty stars, remnants of dwarf galaxies that were once swallowed up by the Milky Way. With a sufficient amount of data, scientists have managed to collect the "skeleton" of the dead galaxies. It's like in paleontology - it's hard to tell from a few bones what the creature looked like, but with enough data, you can assemble a skeleton and guess what the lizard was. So it is here: the information content of the images made it possible to recreate the eleven galaxies that were swallowed up by the Milky Way.

Scientists are confident that as they observe and evaluate the information received, they will be able to find several more new decayed galaxies that were "eaten" by the Milky Way.

We're under fire

According to scientists, the hyperspeed stars in our galaxy did not originate in it, but in the Large Magellanic Cloud. Theorists cannot explain many points regarding the existence of such stars. For example, it is impossible to say for sure why a large number of hyperspeed stars are concentrated in Sextant and in Leo. After revising the theory, scientists came to the conclusion that such a speed can only develop due to the impact on them of a black hole located in the center of the Milky Way.

Recently, more and more stars are being discovered that do not move from the center of our galaxy. After analyzing the trajectory of superfast stars, scientists managed to find out that we are under attack from the Large Magellanic Cloud.

Death of the planet

By observing the planets in our galaxy, scientists were able to see how the planet died. She was consumed by an aging star. During the expansion and transformation into a red giant, the star absorbed its planet. And another planet in the same system changed its orbit. Seeing this and evaluating the state of our Sun, scientists came to the conclusion that the same will happen with our star. In about five million years, it will turn into a red giant.

How the galaxy works

Our Milky Way has several arms that rotate in a spiral. The center of the entire disk is a giant black hole.

In the night sky, we can see the galactic arms. They look like white stripes, reminiscent of a milky road that is strewn with stars. These are the branches of the Milky Way. They are best seen in clear weather during the warm season, when there is the most cosmic dust and gases.

The following arms are distinguished in our galaxy:

1. A branch of a square.
2. Orion. Our solar system is located in this arm. This sleeve is our "room" in the "house".
3. Keel-Sagittarius Sleeve.
4. Branch of Perseus.
5. Shield Branch of the Southern Cross.

It also contains a core, a gas ring, and dark matter. It supplies about 90% of the entire galaxy, and the remaining ten are visible objects.

Our solar system, the Earth and other planets are a single whole of a huge gravitational system that can be seen every night on a clear sky. A variety of processes are constantly taking place in our "house": stars are born, they disintegrate, other galaxies are bombarded, dust, gases appear, stars change and go out, others flare up, dance around ... And all this happens somewhere, far away in a universe about which we know so little. Who knows, maybe the time will come when people will be able to get to other arms and planets of our galaxy in a matter of minutes, travel to other universes.

Since ancient times, the starry sky has attracted the eyes of people. 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 \u200b\u200bwhat our Galaxy looks like according to the latest research, who, why and when gave it such a poetic name and what its expected future is.

origin of name

The expression "Milky Way galaxy" is essentially a tautology. Galactikos in an approximate translation 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, the illegitimate son of Zeus, and in anger splashed breast milk. The drops formed a star track visible on clear nights. Centuries later, scientists discovered that the observed luminaries are only a tiny fraction of the existing celestial bodies. They named the space of the Universe, in which our planet is located, the Galaxy or the Milky Way system. 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. Understanding 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 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 unambiguous 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. The collection of data on the structure of the Galaxy and their correlation with the parameters of other space systems available for study is becoming a kind of substitute for an outside observer.

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 in diameter.

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 can easily overcome any obstacle and allow you to get the desired image. Our Galaxy, according to the data obtained, has a heterogeneous structure.

Conventionally, two elements connected with each other can be distinguished: the halo and the disk itself. The first subsystem has the following characteristics:

• in form it is a sphere;

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

In terms of the density of stars, the galactic disk 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. The name "core" in scientific works either refers only to the central region with a diameter of only a few parsecs, or includes the bulge and the gas ring, which is considered the place of birth 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 large amount of cosmic dust that obscures what our galaxy looks like. Photos and images taken in the infrared range significantly expand the knowledge of astronomers about the core.

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

Light and darkness

The joint influence of black holes on the motion of stars makes its own adjustments to the way our Galaxy looks: it leads to specific changes in orbits that are not typical of cosmic bodies, for example, near the Solar System. The study of these trajectories and the ratio of the velocities of motion with the distance from the center of the Galaxy formed the basis of the now actively developing theory of dark matter. Its nature is still shrouded in mystery. The presence of dark matter, presumably making up the overwhelming part of all matter in the Universe, is recorded only by the effect of gravity on the orbits.

If you scatter all the cosmic dust that hides from us the core, a striking picture will open to the eye. Despite the concentration of dark matter, this part of the universe is full of light emitted by a huge number of stars. There are hundreds of times more of them per unit of space than near the Sun. Roughly ten billion of these form a galactic bar, also called a bar, not quite the usual shape.

Space nut

Examining the center of the system at long wavelengths yielded a detailed infrared image. Our Galaxy, as it turned out, in the core has a structure that resembles an inshell peanut. This “nut” is the bridge, which includes more than 20 million red giants (brighter, but less hot stars).

The spiral arms of the Milky Way radiate from the ends of the bar.

Work related to the discovery of "peanuts" in the center of the star system, not only shed light on what our Galaxy is in structure, but also helped to understand how it developed. Initially, there was an ordinary disk in space, in which a bridge formed over time. Under the influence of internal processes, the bar changed its shape and began to resemble a nut.

Our home on the space map

The active takes place both in the bridge and in the spiral arms possessed by our Galaxy. They were named after the constellations where branches of the branches were found: the arms of Perseus, Cygnus, Centaurus, Sagittarius and Orion. The solar system is located close to the latter (at a distance of at least 28 thousand light years from the core). This area has certain characteristics, according to experts, which made possible the emergence of life on Earth.

The galaxy and our solar system rotate with it. In this case, the patterns of movement of individual components do not coincide. stars from time to time is included in the spiral branches, then separated from them. Only the luminaries lying on the border of the corotation circle do not make such "travels". These include the Sun, protected from powerful processes constantly occurring in the arms. Even a slight shift would negate all other benefits for the development of organisms on our planet.

Diamonds in the sky

The Sun is just one of many similar bodies with which our Galaxy is full. Stars, single or grouped, total more than 400 billion according to the latest data. The nearest to us Proxima Centauri is included in a system of three stars, along with slightly more distant Alpha Centauri A and Alpha Centauri B. The brightest point of the night sky, Sirius A, is located in According to various sources, its luminosity exceeds the solar one by 17-23 times. Sirius is also not alone, it is accompanied by a satellite bearing the same name, but marked B.

Children often begin to get acquainted with what our Galaxy looks like by searching the sky for the Pole Star or Alpha Ursa Minor. It owes its popularity to its position over the North Pole of the Earth. In terms of luminosity, Polaris is much higher than Sirius (almost two thousand times brighter than the Sun), but it cannot dispute the right of Alpha Canis Major to the title of the brightest due to its distance from Earth (estimated from 300 to 465 light years).

Types of luminaries

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

Supergiants have the most impressive dimensions. Neutron stars have the highest concentration of matter per unit volume. Color performance is inextricably linked to temperature:

• the red ones are the coldest;
• heating the surface to 6,000º, like the sun, gives rise to a yellow tint;
• white and blue luminaries have temperatures over 10,000º.

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

The future of the Milky Way

Our Galaxy and other galaxies are constantly in motion and interact. Astronomers have found that the Milky Way has swallowed up its neighbors on several occasions. 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 with the naked eye. As a result, the Milky Way will become an elliptical galaxy.

The endless expanses of space amaze the imagination. It is difficult for an average person to understand the scale 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, which grandiose world we are part of.