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 a plane and in profile looks like a "flying saucer".

The Milky Way with the Andromeda Galaxy (M31), the Triangulum Galaxy (M33), and more than 40 dwarf satellite galaxies - its 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 nucleus, consisting of billions of stars, with a black hole in the center; a disk of stars, gas and dust with a diameter of 100,000 light years and a thickness of 1000 light years, in the middle part of the disk a bulge 3000 light years thick. years; sleeves; a spherical halo (crown) 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 near the center contains many thousands of them. Distances between stars are tens and hundreds of times less than in the vicinity of the Sun.

The galaxy rotates, but not uniformly with the entire disk. As we approach the center, the angular velocity of rotation of stars around the center of the Galaxy increases.

In the plane of the Galaxy, in addition to an 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) is a gas ring - a mixture of gas and dust, strongly radiating in the radio and infrared range. The width of this ring is about 6 thousand light years. It is located in the zone 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 (the Large and Small Magellanic Clouds and other clusters). There are also stars and groups of stars in the galactic corona. 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 planetary system of the Sun makes a revolution around the center of the Galaxy in about 180-220 million Earth years - this is how long one galactic year lasts for us.

In the vicinity of the Sun, it is possible to track sections of two spiral arms that are about 3 thousand light years away from us. According to the constellations where these areas are observed, they were given the name of the Sagittarius arm and the Perseus arm. The sun is located almost in the middle between these spiral arms. But relatively close to us (by galactic standards), in the constellation of 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 compression wave that forms 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, so 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 it that the Sun is located.

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

An analysis of the rotation of the Galaxy showed 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, part of the hidden mass may be in brown dwarfs, in planets gas giants, occupying an intermediate position between stars and planets, and in dense and cold molecular clouds, which have low temperature and are inaccessible to ordinary observations. In addition, in our and other galaxies there are many planet-sized bodies that are not included in any of the circumstellar systems and therefore are not visible in telescopes. Part of the hidden mass of galaxies may belong to "extinguished" stars. According to another hypothesis, the galactic space (vacuum) also contributes to the amount of dark matter. The hidden mass is not only in our galaxy, it is in all galaxies.

The problem of dark matter in astrophysics arose when it became clear that the rotation of galaxies (including our own Milky Way) cannot be correctly described if we take into account only the ordinary visible (luminous) matter contained in them. All the stars of the Galaxy in this case would have to scatter and dissipate 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. In this case, the amount of invisible matter should be approximately six times greater than the amount of visible (information about this is 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 star systems than we do about our own galaxy, the 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 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 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 a small 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 space telescope named after Fermi, designed to observe sources of gamma radiation, discovered two mysterious structures in our Galaxy - two huge bubbles that emit 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 southern directions. May be, we are talking about the streams of particles that once emitted 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 rectilinear translational motion. 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 soon after 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.

Divide by social groups, our Milky Way galaxy will belong to a strong "middle class". So, it belongs to the most common type of galaxy, 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 than it. Our "star island" also has at least 14 satellites - other dwarf galaxies. They are doomed to circle the Milky Way until they are consumed by it, or fly away from an intergalactic collision. Well, so far this is the only place where life certainly exists - that is, we are with you.

But still 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 the galaxy is completely invisible - it is covered with dense sleeves 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 vast world is our Motherland, our solar system. All the 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 in size, and, as you know, one light year is equal to 9460730472580 km. Our solar system is located at a distance of 27,000 light years from the center of the galaxy, in one of the arms, which is called the Orion arm.

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

Deformation

The Milky Way galaxy looks like a disk with a bulge in the center. It's not in perfect shape. On one side 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 disk itself is warped. This is due to the presence of the Small and Large Magellanic Clouds nearby. They orbit 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 like a tug of war between galaxies, creating vibrations. The result is a deformation of the Milky Way galaxy. 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 some more time it will be swallowed up by Andromeda.

Halo

Wondering what kind of galaxy the Milky Way is, scientists began to study it. They managed to find out that for 90% of its mass it consists of dark matter, which causes a mysterious halo. Everything that is visible to the naked eye from the Earth, namely that luminous matter, is about 10% of the galaxy.

Numerous studies have confirmed that the Milky Way has a halo. The scientists compiled various models, which took 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 the planets and other elements of the Milky Way would be less than now. Because of this feature, it was suggested that most of the components consist of an 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 has more than 400 billion stars. About a quarter 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 very different stars, and only a small part, about 3000, is visible from the Earth. 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

Approximately 15% of the galaxy is dust and gases. Maybe because of them our galaxy is called the Milky Way? Despite its huge size, we can see about 6,000 light-years ahead, but the size of the galaxy is 120,000 light-years. Maybe it is more, but even the most powerful telescopes cannot see beyond this. This is due to the accumulation of gas and dust.

The thickness of the dust does not allow visible light to pass through, but infrared light passes through it, and scientists can create maps of the starry sky.

What was before

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

view of the milky way

No scientist, astronomer can say for sure what our Milky Way looks like from above. This is due to the fact that the 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 a snapshot of other visible galaxies, or someone else's fantasy. And we can only guess what it actually looks like. 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 at the very heart. According to assumptions, its dimensions are a little more than 22 million kilometers, and this is the hole itself.

All the matter that tries to get into the hole forms a huge disk, almost 5 million times the size of our Sun. But even such a pulling force does not prevent new stars from forming at the edge of a 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 sleeves appeared. Gradually, it changed, and only about ten billion years ago did it begin to look like it does now.

We are part of something bigger

All 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 groups of clusters over 110 million light-years across. 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. CMB radiation is a convenient reference point that allows you to determine the speed of various matters in the Universe. Studies have shown that our galaxy rotates at a speed of 600 kilometers per second.

Name appearance

The galaxy got its name because of its special appearance, reminiscent of spilled milk in the night sky. The name was given to her in ancient Rome. Then it was called "the road of milk." Until now, it is called that - the Milky Way, associating the name with appearance white streak in the night sky, with spilled milk.

Mentions have been found about the galaxy since the era of Aristotle, who said that the Milky Way is a place where celestial spheres contact with the earth. Until the moment when the telescope was created, no one added anything to this opinion. And only since the seventeenth century people began to look at the world differently.

Our neighbours

For some reason, many people think that the closest 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, we are closer to Canis Major than to the black hole at 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 of class M were discovered in Pse.

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

Collision of galaxies

AT recent times Increasingly, there is information that the nearest galaxy to the Milky Way, the Andromeda Nebula, will swallow 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 move 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 shown in this video:

The collision will not lead to a global catastrophe. And after a few billion years, it will form new system, with familiar galactic shapes.

Dead galaxies

Scientists 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.

A telescope installed in Chile took a huge number of images that allowed scientists to assess the sky. Surrounding our galaxy, according to the images, are halos of dark matter, rarefied gas and few stars, remnants of dwarf galaxies that were once swallowed up by the Milky Way. With enough data, scientists 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 the skeleton and guess what the lizard was. So it is here: the information content of the images made it possible to recreate eleven galaxies that were swallowed up by the Milky Way.

Scientists are confident that as they observe and evaluate the information they receive, 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 hypervelocity 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 exactly why a large number of hypervelocity stars are concentrated in Sextant and Leo. 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 ultrafast stars, scientists managed to find out that we are under attack from the Large Magellanic Cloud.

The 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 swallowed up its planet. And another planet in the same system changed its orbit. Seeing this and assessing the state of our Sun, scientists came to the conclusion that the same thing will happen to our luminary. 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 gigantic black hole.

We can see galactic arms in the night sky. 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. warm time year, when space dust and gases are the most.

Our galaxy has the following arms:

Angle branch.
Orion. Our solar system is located in this arm. This sleeve is our "room" in the "house".
Sleeve Keel-Sagittarius.
Branch of Perseus.
Branch of the Shield of the Southern Cross.

Also in the composition there is a core, a gas ring, 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 in a clear sky. A variety of processes are constantly taking place in our “house”: stars are born, decay, other galaxies are shelling us, dust, gases appear, stars change and go out, others flare up, they 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 reach other arms and planets of our galaxy in a matter of minutes, travel to other universes.

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 quick-tempered Hera: the goddess did not want to feed Hercules, the illegitimate son of Zeus, and in anger sprayed 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. Understanding how 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 an outside perspective, and long 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 writings 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 hardly penetrates into the center of the Milky Way: it collides with large quantity cosmic dust obscuring 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 suggests 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 ratio of motion velocities with 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 you disperse all space dust what the core hides from us, 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. 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.

Work related to the discovery of "peanuts" in the center star system, not only shed light on what our Galaxy is in terms of 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 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 dispute the rights 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. 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. Color characteristic is inextricably linked to 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.