Stars of the Milky Way galaxy. What is the Milky Way

Hello, dear guys! And greetings to you, dear parents! I invite you to go on a small journey into the cosmic world, full of the unknown and enchanting.

How often do we look into a dark sky full of bright stars, trying to find constellations discovered by astronomers. Have you ever seen the Milky Way in the sky? Let's take a closer look at this unique cosmic phenomenon. And at the same time we will get information for an educational and interesting “space” project.

Lesson plan:

Why is it called that?

This star trail in the sky is similar to white strip. Ancient people explained this phenomenon seen in the starry night sky with the help of mythological stories. U different nations there were their own versions of the appearance of an unusual sky strip.

The most widespread hypothesis is that of the ancient Greeks, according to which the Milky Way is nothing more than spilled mother’s milk. greek goddess Gers. Yes and explanatory dictionaries interpret the adjective “milky” as “reminiscent of milk.”

There’s even a song about it, you’ve probably heard it at least once. And if not, then listen right now.

Because of the way the Milky Way looks, it has several names:

the Chinese call it the “yellow road”, believing that it looks more like straw;
The Buryats call the star stripe the “seam of the sky” from which the stars scattered;
among the Hungarians it is associated with the road of warriors;
ancient Indians considered it the milk of the evening red cow.

How to see the “milk track”?

Of course, this is not milk that someone spills across the night sky every day. The Milky Way is a giant star system called a “Galaxy”. In appearance, it looks like a spiral, in the center of which there is a core, and arms extend from it like rays, of which the Galaxy has four.

How to find this white path of stars? You can even see a star cluster with the naked eye in the night sky when there are no clouds. All inhabitants of the Milky Way are located on the same line.

If you are a resident of the northern hemisphere, then you can find a place where there is a scattering of stars at midnight in July. In August, when it gets dark earlier, it will be possible to search for the spiral of the Galaxy starting at ten in the evening, and in September - after 20.00. You can see all the beauty by first finding the constellation Cygnus and moving from it with your gaze to the north - northeast.

To see the brightest stellar segments, you need to go to the equator, or even better, closer to 20-40 degrees south latitude. It is there that at the end of April - beginning of May the Southern Cross and Sirius flaunt in the night sky, between which the treasured galactic star path passes.

When the constellations Sagittarius and Scorpio rise in the eastern part by June-July, the Milky Way gains particular brightness, and clouds of cosmic dust can even be seen between distant stars.

Seeing various photographs, many wonder: why do we see not a spiral, but only a stripe? The answer to this question is very simple: we are inside the Galaxy! If we stand in the center of a sports hoop and raise it at eye level, what will we see? That's right: a stripe in front of your eyes!

The galactic core can be found in the constellation Sagittarius using radio telescopes. But you shouldn’t expect much brightness from it. The central part is the darkest due to large quantity there is cosmic dust in it.

What is the Milky Way made of?

Our Galaxy is just one of millions of star systems that have been found by astronomers, but it is quite a large one. The Milky Way has approximately 300 billion stars. The Sun, which rises every day in the sky, is also part of them, revolving around the core. The Galaxy has stars much larger and brighter than the Sun, and there are smaller ones that emit faint light.

They differ not only in size, but also in color - they can be white-blue (they are the hottest) and red (the coldest). They all move together in a circle along with the planets. Just imagine that we go through a full revolution around the galactic circle in almost 250 million years - that’s how long one galactic year lasts.

Stars live in the strip of the Milky Way, forming groups that scientists call clusters, differing in age and stellar composition.

Small open clusters are the youngest, they are only about 10 million years old, but this is where the massive and bright celestial representatives live. Such groups of stars are located along the edge of the plane.
Globular clusters are very old, they were formed over 10 - 15 billion years, they are located in the center.

10 interesting facts

As always, I advise you to decorate your research work the most interesting “galactic” facts. Watch the video carefully and be surprised!

This is our Galaxy, in which we live among wonderful, bright neighbors. If you are not yet personally familiar with the “milk path,” then quickly go outside to see all the starry beauty in the night sky.

By the way, have you already read the article about our cosmic neighbor the Moon? Not yet? Then take a look soon)

Good luck in your studies!

Evgenia Klimkovich.

In our age, illuminated by hundreds of electric lights, city residents have no opportunity to see the Milky Way. This phenomenon, which appears in our sky only during a certain period of the year, is observed only far from large settlements. In our latitudes it is especially beautiful in August. In the last month of summer, the Milky Way rises above the Earth in the form of a giant celestial arch. This weak, blurry strip of light appears denser and brighter in the direction of Scorpio and Sagittarius, and paler and more diffuse near Perseus.

Star Riddle

The Milky Way is an unusual phenomenon, the secret of which has not been revealed to people for a whole string of centuries. In the legends and myths of many peoples it was called differently. The amazing glow was the mysterious Star Bridge leading to heaven, the Road of the Gods and the magical Heavenly River carrying divine milk. At the same time, all peoples believed that the Milky Way was something sacred. The radiance was worshiped. Even temples were built in his honor.

Few people know that our Christmas tree is an echo of the cults of people who lived in earlier times. Indeed, in ancient times it was believed that the Milky Way was the axis of the Universe or the World Tree, on whose branches stars ripened. That is why at the beginning of the annual cycle they decorated the Christmas tree. The earthly tree was an imitation of the eternally fruitful tree of heaven. Such a ritual gave hope for the favor of the gods and good harvest. So great was the importance of the Milky Way for our ancestors.

Scientific assumptions

What is the Milky Way? The history of the discovery of this phenomenon goes back almost 2000 years. Plato also called this strip of light a seam connecting the celestial hemispheres. In contrast to this, Anaxagoras and Demoxide argued that the Milky Way (we’ll look at what color it is) is a kind of illumination of stars. She is the decoration of the night sky. Aristotle explained that the Milky Way is the glow of luminous lunar vapors in the air of our planet.

There were many other assumptions. Thus, the Roman Marcus Manilius said that the Milky Way is a constellation of small heavenly bodies. It was he who was closest to the truth, but he could not confirm his assumptions in those days when the sky was observed only with the naked eye. All ancient researchers believed that the Milky Way was part of the solar system.

Galileo's discovery

It was caused by the presence of not only star clusters in the celestial phenomenon. There are also dark clouds there. The combination of these two elements creates an amazing image of a night phenomenon.

William Herschel's discovery

The study of the Milky Way continued into the 18th century. During this period, its most active researcher was William Herschel. The famous composer and musician was engaged in the manufacture of telescopes and studied the science of stars. Herschel's most important discovery was the Great Plan of the Universe. This scientist observed the planets through a telescope and counted them in different parts of the sky. Research has led to the conclusion that the Milky Way is a kind of star island in which our Sun is located. Herschel even drew a schematic plan of his discovery. In the figure, the star system was depicted in the form of a millstone and had an elongated irregular shape. At the same time, the sun was inside this ring that surrounded our world. This is exactly how all scientists imagined our Galaxy until the beginning of the last century.

It was only in the 1920s that the work of Jacobus Kaptein was published, in which the Milky Way was described in the most detail. At the same time, the author gave a diagram of the star island, as similar as possible to the one that is currently known to us. Today we know that the Milky Way is a Galaxy that contains the Solar System, the Earth and those individual stars that are visible to humans with the naked eye.

Structure of galaxies

With the development of science, astronomical telescopes became more and more powerful. At the same time, the structure of the observed galaxies became increasingly clear. It turned out that they are not similar to each other. Some of them were incorrect. Their structure had no symmetry.

Elliptical and spiral galaxies have also been observed. What type of these types does the Milky Way belong to? This is our Galaxy, and, being inside, it is very difficult to determine its structure. However, scientists have found an answer to this question. Now we know what the Milky Way is. Its definition was given by researchers who established that it is a disk with an internal core.

general characteristics

The Milky Way is a spiral galaxy. Moreover, it has a bridge in the form of a huge interconnected gravitational force.

The Milky Way is believed to have existed for over thirteen billion years. This is the period during which about 400 billion constellations and stars, over a thousand huge gas nebulae, clusters and clouds were formed in this Galaxy.

The shape of the Milky Way is clearly visible on the map of the Universe. Upon examination, it becomes clear that this cluster of stars is a disk whose diameter is 100 thousand light years (one such light year is ten trillion kilometers). The thickness is 15 thousand, and the depth is about 8 thousand light years.

How much does the Milky Way weigh? This (the definition of its mass is very difficult task) it is not possible to calculate. Difficulties arise in determining the mass of dark matter, which does not interact with electromagnetic radiation. This is why astronomers cannot definitively answer this question. But there are rough calculations according to which the weight of the Galaxy ranges from 500 to 3000 billion solar masses.

The Milky Way is like all celestial bodies. It rotates around its axis, moving through the Universe. Astronomers point to the uneven, even chaotic movement of our Galaxy. This is explained by the fact that each of the stellar systems and nebulae included in its composition has its own speed, different from the others, and also different shapes and types of orbits.

What parts does the Milky Way consist of? These are the core and bridges, the disc and spiral arms, and the crown. Let's take a closer look at them.

Core

This part of the Milky Way is located in the core. There is a source of non-thermal radiation with a temperature of about ten million degrees. At the center of this part of the Milky Way is a compaction called a “bulge.” This is a whole string of old stars that moves along an elongated orbit. Most of these celestial bodies life cycle is already coming to an end.

In the central part of the core of the Milky Way is located. This section of outer space, the weight of which is equal to the mass of three million suns, has the most powerful gravity. Another black hole rotates around it, only smaller. Such a system creates such a force that nearby constellations and stars move along very unusual trajectories.

The center of the Milky Way has other features. Thus, it is characterized by a large cluster of stars. Moreover, the distance between them is hundreds of times smaller than that observed on the periphery of the formation.

It is also interesting that, observing the nuclei of other galaxies, astronomers note their bright shine. But why is it not visible in the Milky Way? Some researchers have even suggested that there is no core in our Galaxy. However, it was determined that in spiral nebulae there are dark layers that are interstellar accumulations of dust and gas. They are also found in the Milky Way. These huge dark clouds prevent the earthly observer from seeing the glow of the core. If such a formation did not interfere with earthlings, then we could observe the core in the form of a shining ellipsoid, the size of which would exceed the diameter of one hundred moons.

Modern telescopes, which are capable of operating in special ranges of the electromagnetic spectrum of radiation, have helped people answer this question. With the help of this modern technology, which was able to bypass the dust shield, scientists were able to see the core of the Milky Way.

Jumper

This element of the Milky Way crosses its central section and has a size of 27 thousand light years. The bridge consists of 22 million red stars of impressive age. Around this formation there is a gas ring, which contains a large percentage of molecular oxygen. All this suggests that the bridge of the Milky Way is the area where the greatest number stars are formed.

Disk

This shape has the Milky Way itself, which is in constant rotational movement. Interestingly, the speed of this process depends on the distance of a particular area from the nucleus. So, in the very center it is equal to zero. At a distance of two thousand light years from the core, the rotation speed is 250 kilometers per hour.

The outer side of the Milky Way is surrounded by a layer of atomic hydrogen. Its thickness is 1.5 thousand light years.

On the outskirts of the Galaxy, astronomers have discovered the presence of dense gas clusters with a temperature of 10 thousand degrees. The thickness of such formations is several thousand light years.

Five spiral arms

These are another component of the Milky Way, located directly behind the gas ring. The spiral arms cross the constellations Cygnus and Perseus, Orion and Sagittarius, and Centaurus. These formations are unevenly filled with molecular gas. This composition introduces errors into the rules of rotation of the Galaxy.
The spiral arms extend directly from the core of the star island. We observe them with the naked eye, calling the light stripe Milky Way.

The spiral branches are projected onto each other, which makes it difficult to understand their structure. Scientists suggest that such arms were formed due to the presence in the Milky Way of giant waves of rarefaction and compression of interstellar gas, which move from the core to the galactic disk.

Crown

The Milky Way has a spherical halo. This is his crown. This formation consists of individual stars and clusters of constellations. Moreover, the dimensions of the spherical halo are such that it extends beyond the boundaries of the Galaxy by 50 light years.

The Milky Way's corona typically contains low-mass and old stars, as well as dwarf galaxies and hot gas clusters. All these components move in elongated orbits around the nucleus, performing random rotation.

There is a hypothesis according to which the emergence of the corona was a consequence of the absorption of small galaxies by the Milky Way. According to astronomers, the age of the halo is about twelve billion years.

Location of stars

In a cloudless night sky, the Milky Way is visible from anywhere on our planet. However, only part of the Galaxy is accessible to human eyes, which is a system of stars located inside the Orion arm.

What is the Milky Way? The definition of all its parts in space becomes most clear if we consider a star map. In this case, it becomes clear that the Sun, which illuminates the Earth, is located almost on the disk. This is almost the edge of the Galaxy, where the distance from the core is 26-28 thousand light years. Moving at a speed of 240 kilometers per hour, the Sun spends 200 million years on one revolution around the core, so during its entire existence it traveled around the disk, circling the core, only thirty times.

Our planet is located in the so-called corotation circle. This is a place where the rotation speeds of the arms and stars are identical. This circle is characterized by an increased level of radiation. That is why life, as scientists believe, could only arise on that planet near which there are a small number of stars.

Our Earth was such a planet. It is located on the periphery of the Galaxy, in its quietest place. This is why there have been no global cataclysms on our planet for several billion years, which often occur in the Universe.

Forecast for the future

Scientists suggest that in the future, collisions between the Milky Way and other galaxies are very likely, the largest of which is the Andromeda galaxy. But at the same time, it is not possible to talk specifically about anything. This requires knowledge about the magnitude of the transverse velocities of extragalactic objects, which are not yet available to modern researchers.

In September 2014, one of the models for the development of events was published in the media. According to it, four billion years will pass, and the Milky Way will absorb the Magellanic Clouds (Large and Small), and in another billion years it itself will become part of the Andromeda Nebula.

> Milky Way

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

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

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

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

Interesting facts about the Milky Way galaxy

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

Discovering and naming the Milky Way galaxy

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

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

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

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

Our galaxy: a view from the inside

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

Location of the Milky Way Galaxy

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

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

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

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

A lot of dust and gas accumulate in the spiral arms, which creates excellent conditions for the formation of new stars. The arms extend from the galactic disk, spanning approximately 1,000 light years.

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

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

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

Structure and composition of the Milky Way galaxy

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

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

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

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

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

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

Stellar population of the galaxy

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

Position of the Sun in the Milky Way Galaxy

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

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

Collision trajectory of the Milky Way galaxy

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

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

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

What's next for the Milky Way galaxy?

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

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

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

Position and movement of the Milky Way

The Milky Way is the galaxy that contains the Earth, the solar system, and all the individual stars visible to the naked eye. Refers to barred spiral galaxies.

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

History of discovery

Galileo's discovery

The Milky Way revealed its secret only in 1610. It was then that the first telescope was invented, which was used by Galileo Galilei. The famous scientist saw through the device that the Milky Way was a real cluster of stars, which, when viewed with the naked eye, merged into a continuous, faintly flickering strip. Galileo even managed to explain the heterogeneity of the structure of this band. It was caused by the presence of not only star clusters in the celestial phenomenon. There are also dark clouds there. The combination of these two elements creates an amazing image of a night phenomenon.

William Herschel's discovery

The study of the Milky Way continued into the 18th century. During this period, its most active researcher was William Herschel. The famous composer and musician was engaged in the manufacture of telescopes and studied the science of stars. Herschel's most important discovery was the Great Plan of the Universe. This scientist observed the planets through a telescope and counted them in different parts of the sky. Research has led to the conclusion that the Milky Way is a kind of star island in which our Sun is located. Herschel even drew a schematic plan of his discovery. In the picture, the star system was depicted in the form of a millstone and had an elongated irregular shape. At the same time, the sun was inside this ring that surrounded our world. This is exactly how all scientists imagined our Galaxy until the beginning of the last century.

What shape does the Milky Way have?

When studying galaxies, Edwin Hubble classified them into different kinds elliptical and spiral. Spiral galaxies are disk-shaped with spiral arms inside. Since the Milky Way is disk-shaped along with spiral galaxies, it is logical to assume that it is likely a spiral galaxy.

In the 1930s, R. J. Trumpler realized that the estimates of the size of the Milky Way galaxy made by Capetin and other scientists were erroneous because the measurements were based on observations using radiation waves in the visible region of the spectrum. Trumpler concluded that the huge amount of dust in the plane of the Milky Way absorbs visible light. Therefore, distant stars and their clusters seem more ghostly than they really are. Because of this, to accurately image the stars and star clusters inside the Milky Way, astronomers had to find a way to see through the dust.

In the 1950s, the first radio telescopes were invented. Astronomers have discovered that hydrogen atoms emit radiation in radio waves, and that such radio waves can penetrate dust in the Milky Way. Thus, it became possible to see the spiral arms of this galaxy. For this purpose, the marking of stars was used by analogy with marks when measuring distances. Astronomers realized that spectral type O and B stars could serve to achieve this goal.

Such stars have several features:

brightness– they are very noticeable and often found in small groups or associations;
warm– they emit waves different lengths(visible, infrared, radio waves);
short life time– they live about 100 million years. Given the speed at which stars rotate at the center of the galaxy, they do not travel far from their birthplace.

Astronomers can use radio telescopes to pinpoint the positions of O and B stars and, based on Doppler shifts in the radio spectrum, determine their speed. After performing such operations on many stars, scientists were able to produce combined radio and optical maps of the Milky Way's spiral arms. Each arm is named after the constellation that exists in it.

Astronomers believe that the movement of matter around the center of the galaxy creates density waves (regions of high and low density), just like what you see when you mix cake batter with an electric mixer. These density waves are believed to have caused the spiral nature of the galaxy.

Thus, by viewing the sky at different wavelengths (radio, infrared, visible, ultraviolet, x-ray) using various ground-based and space telescopes, different images of the Milky Way can be obtained.

Doppler effect. Just as the high-pitched sound of a fire truck siren becomes lower as the vehicle moves away, the movement of stars affects the wavelengths of light that travel from them to Earth. This phenomenon is called the Doppler effect. We can measure this effect by measuring the lines in the star's spectrum and comparing them to the spectrum of a standard lamp. The degree of Doppler shift shows how fast the star is moving relative to us. Additionally, the direction of the Doppler shift can tell us the direction in which the star is moving. If the spectrum of a star shifts to the blue end, then the star is moving towards us; if in the red direction, it moves away.

Structure of the Milky Way

If we carefully examine the structure of the Milky Way, we will see the following:

Galactic disk. Most of the stars in the Milky Way are concentrated here.

The disk itself is divided into the following parts:

The nucleus is the center of the disk;
Arcs are the areas around the nucleus, including the areas directly above and below the plane of the disk.
Spiral arms are areas that extend outward from the center. Our Solar System is located in one of the spiral arms of the Milky Way.

Globular clusters. Several hundred of them are scattered above and below the plane of the disk.
Halo. This is a large, dim region that surrounds the entire galaxy. The halo consists of high-temperature gas and possibly dark matter.

The radius of the halo is significantly larger than the size of the disk and, according to some data, reaches several hundred thousand light years. The center of symmetry of the Milky Way halo coincides with the center of the galactic disk. The halo consists mainly of very old, dim stars. The age of the spherical component of the Galaxy exceeds 12 billion years. The central, densest part of the halo within several thousand light years from the center of the Galaxy is called bulge(translated from English as “thickening”). The halo as a whole rotates very slowly.

Compared to halo disk spins noticeably faster. It looks like two plates folded at the edges. The diameter of the Galaxy's disk is about 30 kpc (100,000 light years). The thickness is about 1000 light years. The rotation speed is not the same at different distances from the center. It quickly increases from zero in the center to 200-240 km/s at a distance of 2 thousand light years from it. The mass of the disk is 150 billion times greater than the mass of the Sun (1.99 * 10 30 kg). Young stars and star clusters are concentrated in the disk. Among them are many bright and hot stars. Gas in the galactic disk is distributed unevenly, forming giant clouds. Main chemical element in our Galaxy is hydrogen. Approximately 1/4 of it consists of helium.

One of the most interesting regions of the Galaxy is its center, or core, located in the direction of the constellation Sagittarius. The visible radiation from the central regions of the Galaxy is completely hidden from us by thick layers of absorbing matter. Therefore, it began to be studied only after the creation of receivers for infrared and radio radiation, which are absorbed to a lesser extent. The central regions of the Galaxy are characterized by a strong concentration of stars: there are many thousands of them in each cubic parsec. Closer to the center, areas of ionized hydrogen and numerous sources of infrared radiation are noted, indicating star formation occurring there. In the very center of the Galaxy, the existence of a massive compact object is assumed - a black hole with a mass of about a million solar masses.

One of the most notable formations is spiral branches (or sleeves). They gave the name to this type of objects – spiral galaxies. Along the arms are mainly concentrated the youngest stars, many open star clusters, as well as chains of dense clouds of interstellar gas in which stars continue to form. Unlike a halo, where any manifestations of stellar activity are extremely rare, vigorous life continues in the branches, associated with the continuous transition of matter from interstellar space to stars and back. The spiral arms of the Milky Way are largely hidden from us by absorbing matter. Their detailed study began after the advent of radio telescopes. They made it possible to study the structure of the Galaxy by observing the radio emission of interstellar hydrogen atoms concentrated along long spirals. According to modern concepts, spiral arms are associated with compression waves propagating across the galactic disk. Passing through regions of compression, the matter of the disk becomes denser, and the formation of stars from gas becomes more intense. The reasons for the appearance of such a unique wave structure in the disks of spiral galaxies are not entirely clear. Many astrophysicists are working on this problem.

The Sun's Place in the Galaxy

In the vicinity of the Sun, it is possible to trace sections of two spiral branches, distant from us by about 3 thousand light years. Based on the constellations where these areas are found, they are called the Sagittarius arm and the Perseus arm. The sun is almost halfway between these spiral arms. True, relatively close (by galactic standards) to us, in the constellation Orion, there passes another, not so clearly expressed branch, which is considered a branch of one of the main spiral arms of the Galaxy.

The distance from the Sun to the center of the Galaxy is 23-28 thousand light years, or 7-9 thousand parsecs. This suggests that the Sun is located closer to the outskirts of the disk than to its center.

Together with all nearby stars, the Sun rotates around the center of the Galaxy at a speed of 220–240 km/s, completing one revolution in approximately 200 million years. This means that during its entire existence, the Earth has flown around the center of the Galaxy no more than 30 times.

The speed of rotation of the Sun around the center of the Galaxy practically coincides with the speed with which the compaction wave, forming the spiral arm, moves in this region. This situation is generally unusual for the Galaxy: the spiral branches rotate at a constant angular velocity, like the spokes of a wheel, and the movement of stars, as we have seen, obeys a completely different pattern. Therefore, almost the entire stellar population of the disk either falls inside the spiral branch or leaves it. The only place where the velocities of stars and spiral arms coincide is the so-called corotation circle, and it is on it that the Sun is located!

This circumstance is extremely favorable for the Earth. Indeed, violent processes occur in the spiral branches, generating powerful radiation that is destructive for all living things. And no atmosphere could protect from it. But our planet exists in a relatively calm place in the Galaxy and for hundreds of millions and billions of years has not experienced the influence of these cosmic cataclysms. Perhaps this is why life could originate and survive on Earth.

For a long time, the position of the Sun among the stars was considered the most ordinary. Today we know that this is not so: in a certain sense it is privileged. And this must be taken into account when discussing the possibility of the existence of life in other parts of our Galaxy.

Location of stars

In a cloudless night sky, the Milky Way is visible from anywhere on our planet. However, only part of the Galaxy is accessible to human eyes, which is a system of stars located inside the Orion arm. What is the Milky Way? The definition of all its parts in space becomes most clear if we consider a star map. In this case, it becomes clear that the Sun, which illuminates the Earth, is located almost on the disk. This is almost the edge of the Galaxy, where the distance from the core is 26-28 thousand light years. Moving at a speed of 240 kilometers per hour, the Sun spends 200 million years on one revolution around the core, so during its entire existence it traveled around the disk, circling the core, only thirty times. Our planet is located in the so-called corotation circle. This is a place where the rotation speeds of the arms and stars are identical. This circle is characterized by an increased level of radiation. That is why life, as scientists believe, could only arise on that planet near which there are a small number of stars. Our Earth was such a planet. It is located on the periphery of the Galaxy, in its quietest place. This is why there have been no global cataclysms on our planet for several billion years, which often occur in the Universe.

What will the death of the Milky Way look like?

The cosmic story of the death of our galaxy begins here and now. We may look around blindly, thinking that the Milky Way, Andromeda (our big sister) and a bunch of unknowns - our cosmic neighbors - are our home, but in reality there is much more to it. It's time to explore what else is around us. Go.

Triangulum Galaxy. With a mass of approximately 5% of the Milky Way's mass, it is the third largest galaxy in the local group. It has a spiral structure, its own satellites and may be a satellite of the Andromeda galaxy.
Large Magellanic Cloud. This galaxy makes up only 1% of the mass of the Milky Way, but is the fourth largest in our local group. It is very close to our Milky Way—less than 200,000 light-years away—and is undergoing active star formation as tidal interactions with our galaxy cause gas to collapse and produce new, hotter, larger stars in the Universe.
Small Magellanic Cloud, NGC 3190 and NGC 6822. All of them have a mass between 0.1% and 0.6% of the Milky Way (and it is not clear which is larger) and all three are independent galaxies. Each of them contains more than a billion solar masses material.
Elliptical galaxies M32 and M110. They may be "only" satellites of Andromeda, but they each have more than a billion stars, and they may even be more massive than numbers 5, 6, and 7.

In addition, there are at least 45 other known smaller galaxies that make up our local group. Each of them has a halo of dark matter surrounding it; each of them is gravitationally tied to the other, located at a distance of 3 million light years. Despite their size, mass and size, none of them will remain in a few billion years.

So, the main thing

As time passes, galaxies interact gravitationally. They not only pull together due to gravitational attraction, but also interact tidally. We usually talk about tides in the context of the Moon pulling on Earth's oceans and creating high and low tides, and this is partly true. But from a galactic perspective, tides are a less noticeable process. The part of a small galaxy that is close to a large one will be attracted with greater gravitational force, and the part that is further away will experience less gravity. As a result, the small galaxy will stretch out and eventually break apart under the influence of gravity.

Small galaxies that are part of our local group, including both Magellanic clouds and dwarf elliptical galaxies, will be torn apart in this way, and their material will be included in the large galaxies with which they merge. “So what,” you say. After all, this is not completely death, because large galaxies will remain alive. But even they will not exist forever in this state. In 4 billion years, the mutual gravitational pull of the Milky Way and Andromeda will pull the galaxies into a gravitational dance that will lead to a great merger. Although this process will take billions of years, the spiral structure of both galaxies will be destroyed, resulting in the creation of a single, giant elliptical galaxy at the core of our local group: Mammals.

A small percentage of stars will be ejected during such a merger, but most will remain intact and there will be a large burst of star formation. Eventually, the rest of the galaxies in our local group will also be sucked in, leaving one big giant galaxy that has devoured the rest. This process will occur in all connected groups and clusters of galaxies throughout the Universe, while dark energy pushes individual groups and clusters away from each other. But this cannot be called death, because the galaxy will remain. And it will be like this for some time. But the galaxy is made of stars, dust and gas, and everything will come to an end someday.

Throughout the Universe, galactic mergers will take place over tens of billions of years. During the same time, dark energy will drag them throughout the Universe to a state of complete solitude and inaccessibility. And although the last galaxies outside our local group will not disappear until hundreds of billions of years have passed, the stars in them will live. The longest-lived stars in existence today will continue to burn their fuel for tens of trillions of years, and new stars will emerge from the gas, dust and stellar corpses that populate every galaxy - albeit fewer and fewer.

When the last stars burn out, only their corpses will remain - white dwarfs and neutron stars. They will shine for hundreds of trillions or even quadrillions of years before they go out. When that inevitable happens, we'll be left with brown dwarfs (failed stars) that randomly merge, reignite nuclear fusion, and create starlight over tens of trillions of years.

When the last star goes out tens of quadrillions of years in the future, there will still be some mass left in the galaxy. This means that this cannot be called “true death.”

All masses gravitationally interact with each other, and gravitational objects of different masses exhibit strange properties when interacting:

Repeated “approaches” and close passes cause exchanges of speed and impulses between them.
Objects with low mass are ejected from the galaxy, and objects with higher mass sink into the center, losing speed.
Over a sufficiently long period of time, most of the mass will be ejected, and only a small part of the remaining mass will be firmly attached.

At the very center of these galactic remains there will be a supermassive black hole in every galaxy, and the rest of the galactic objects will orbit a larger version of our own solar system. Of course, this structure will be the last, and since the black hole will be as large as possible, it will eat everything it can reach. At the center of Milkomeda there will be an object hundreds of millions of times more massive than our Sun.

But this will come to an end too?

Thanks to the phenomenon of Hawking radiation, even these objects will one day decay. It will take about 10,80 to 10,100 years, depending on how massive our supermassive black hole becomes as it grows, but the end is coming. After this, the remains orbiting around the galactic center will unravel and leave only a halo of dark matter, which can also randomly dissociate, depending on the properties of this very matter. Without any matter there will no longer be anything that we once called the local group, the Milky Way and other names dear to our hearts.

Mythology

Armenian, Arabic, Wallachian, Jewish, Persian, Turkish, Kyrgyz

According to one of the Armenian myths about the Milky Way, the god Vahagn, the ancestor of the Armenians, stole straw from the ancestor of the Assyrians, Barsham, in the harsh winter and disappeared into the sky. When he walked with his prey across the sky, he dropped straws on his way; from them a light trail was formed in the sky (in Armenian “Straw Thief Road”). The myth of scattered straw is also spoken of in Arabic, Jewish, Persian, Turkish and Kyrgyz names (Kirg. Samanchyn Zholu– the strawman’s path) of this phenomenon. The people of Wallachia believed that Venus stole this straw from St. Peter.

Buryat

According to Buryat mythology, good forces create peace and change the universe. Thus, the Milky Way arose from the milk that Manzan Gourmet strained from her breast and splashed out after Abai Geser, who deceived her. According to another version, the Milky Way is a “seam of the sky”, sewn up after the stars poured out of it; Tengris walk along it, like on a bridge.

Hungarian

According to Hungarian legend, Attila would descend the Milky Way if the Székelys were in danger; the stars represent sparks from hooves. Milky Way. accordingly, it is called the “road of warriors”.

Ancient Greek

Etymology of the word Galaxias (Γαλαξίας) and its connection with milk (γάλα) reveal two similar ancient greek myth. One of the legends tells about the mother’s milk spilling across the sky from the goddess Hera, who was breastfeeding Hercules. When Hera learned that the baby she was nursing was not her own child, but the illegitimate son of Zeus and an earthly woman, she pushed him away, and the spilled milk became the Milky Way. Another legend says that the spilled milk was the milk of Rhea, the wife of Kronos, and the baby was Zeus himself. Kronos devoured his children because it was foretold that he would be overthrown by his own son. Rhea hatched a plan to save her sixth child, newborn Zeus. She wrapped a stone in baby clothes and slipped it to Kronos. Kronos asked her to feed her son one more time before he swallowed him. The milk spilled from Rhea's breast onto a bare rock later became known as the Milky Way.

Indian

Ancient Indians considered the Milky Way to be the milk of the evening red cow passing across the sky. In the Rig Veda, the Milky Way is called the throne road of Aryaman. The Bhagavata Purana contains a version according to which the Milky Way is the belly of a celestial dolphin.

Inca

The main objects of observation in Inca astronomy (which was reflected in their mythology) in the sky were the dark areas of the Milky Way - peculiar “constellations” in the terminology of Andean cultures: Lama, Baby Lama, Shepherd, Condor, Partridge, Toad, Snake, Fox; as well as the stars: Southern Cross, Pleiades, Lyra and many others.

Ketskaya

In Ket myths, similar to the Selkup ones, the Milky Way is described as the road of one of three mythological characters: the Son of Heaven (Esya), who went hunting to the western side of the sky and froze there, the hero Albe, who pursued the evil goddess, or the first shaman Doha, who climbed this road to the sun.

Chinese, Vietnamese, Korean, Japanese

In the mythologies of the Sinosphere, the Milky Way is called and compared to a river (in Vietnamese, Chinese, Korean and Japanese the name “silver river” is retained. The Chinese also sometimes called the Milky Way the “Yellow Road”, after the color of the straw.

Indigenous peoples of North America

The Hidatsa and Eskimos call the Milky Way "The Ash". Their myths tell of a girl who scattered ashes across the sky so that people could find their way home at night. The Cheyenne believed that the Milky Way was mud and silt raised by the belly of a turtle swimming through the sky. Eskimos from the Bering Strait - that these are the traces of the Creator Raven walking across the sky. The Cherokees believed that the Milky Way was formed when one hunter stole the wife of another out of jealousy, and her dog began to eat cornmeal left unattended and scattered it across the sky (the same myth is found among the Khoisan people of the Kalahari). Another myth of the same people says that the Milky Way is the footprint of a dog dragging something across the sky. The Ktunaha called the Milky Way the “tail of the dog,” and the Blackfoot called it the “wolf road.” Wyandot myth says that the Milky Way is a place where the souls of dead people and dogs come together and dance.

Maori

In Maori mythology, the Milky Way is considered the boat of Tama-rereti. The bow of the boat is the constellation Orion and Scorpio, the anchor is the Southern Cross, Alpha Centauri and Hadar are the rope. According to legend, one day Tama-rereti was sailing in his canoe and saw that it was late and he was far from home. There were no stars in the sky, and, fearing that Tanifa might attack, Tama-rereti began throwing sparkling pebbles into the sky. The heavenly deity Ranginui liked what he was doing and placed Tama-rereti's boat in the sky and turned the pebbles into stars.

Finnish, Lithuanian, Estonian, Erzya, Kazakh

The Finnish name is Finnish. Linnunrata– means “Way of the Birds”; the Lithuanian name has a similar etymology. Estonian myth also connects the Milky Way with bird flight.

The Erzya name is “Kargon Ki” (“Crane Road”).

The Kazakh name is “Kus Zholy” (“Path of the Birds”).

Interesting facts about the Milky Way galaxy

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

The Milky Way is the galaxy that contains the Earth, the solar system, and all the individual stars visible to the naked eye. Refers to barred spiral galaxies.

History of discovery

Galileo's discovery

William Herschel's discovery

The study of the Milky Way continued into the 18th century. During this period, its most active researcher was William Herschel. The famous composer and musician was engaged in the manufacture of telescopes and studied the science of stars. Herschel's most important discovery was the Great Plan of the Universe. This scientist observed the planets through a telescope and counted them in different parts of the sky. Research has led to the conclusion that the Milky Way is a kind of star island in which our Sun is located. Herschel even drew a schematic plan of his discovery. In the picture, the star system was depicted in the form of a millstone and had an elongated irregular shape. At the same time, the sun was inside this ring that surrounded our world. This is exactly how all scientists imagined our Galaxy until the beginning of the last century.

What shape does the Milky Way have?

When studying galaxies, Edwin Hubble classified them into various types of elliptical and spiral. Spiral galaxies are disk-shaped with spiral arms inside. Since the Milky Way is disk-shaped along with spiral galaxies, it is logical to assume that it is likely a spiral galaxy.

Such stars have several features:

brightness– they are very noticeable and often found in small groups or associations;
warm– they emit waves of different lengths (visible, infrared, radio waves);
short life time– they live about 100 million years. Given the speed at which stars rotate at the center of the galaxy, they do not travel far from their birthplace.

Thus, by viewing the sky at different wavelengths (radio, infrared, visible, ultraviolet, x-ray) using various ground-based and space telescopes, different images of the Milky Way can be obtained.

Doppler effect. Just as the high-pitched sound of a fire truck siren becomes lower as the vehicle moves away, the movement of stars affects the wavelengths of light that travel from them to Earth. This phenomenon is called the Doppler effect. We can measure this effect by measuring the lines in the star's spectrum and comparing them to the spectrum of a standard lamp. The degree of Doppler shift shows how fast the star is moving relative to us. Additionally, the direction of the Doppler shift can tell us the direction in which the star is moving. If the spectrum of a star shifts to the blue end, then the star is moving towards us; if in the red direction, it moves away.

Structure of the Milky Way

If we carefully examine the structure of the Milky Way, we will see the following:

Galactic disk. Most of the stars in the Milky Way are concentrated here.

The disk itself is divided into the following parts:

The nucleus is the center of the disk;
Arcs are the areas around the nucleus, including the areas directly above and below the plane of the disk.
Spiral arms are areas that extend outward from the center. Our Solar System is located in one of the spiral arms of the Milky Way.

Globular clusters. Several hundred of them are scattered above and below the plane of the disk.
Halo. This is a large, dim region that surrounds the entire galaxy. The halo consists of high-temperature gas and possibly dark matter.

Compared to halo disk spins noticeably faster. It looks like two plates folded at the edges. The diameter of the Galaxy's disk is about 30 kpc (100,000 light years). The thickness is about 1000 light years. The rotation speed is not the same at different distances from the center. It quickly increases from zero in the center to 200-240 km/s at a distance of 2 thousand light years from it. The mass of the disk is 150 billion times greater than the mass of the Sun (1.99 * 10 30 kg). Young stars and star clusters are concentrated in the disk. Among them are many bright and hot stars. Gas in the galactic disk is distributed unevenly, forming giant clouds. The main chemical element in our Galaxy is hydrogen. Approximately 1/4 of it consists of helium.

The Sun's Place in the Galaxy

Location of stars

What will the death of the Milky Way look like?

Triangulum Galaxy. With a mass of approximately 5% of the Milky Way's mass, it is the third largest galaxy in the local group. It has a spiral structure, its own satellites and may be a satellite of the Andromeda galaxy.
Large Magellanic Cloud. This galaxy makes up only 1% of the mass of the Milky Way, but is the fourth largest in our local group. It is very close to our Milky Way—less than 200,000 light-years away—and is undergoing active star formation as tidal interactions with our galaxy cause gas to collapse and produce new, hotter, larger stars in the Universe.
Small Magellanic Cloud, NGC 3190 and NGC 6822. All of them have a mass between 0.1% and 0.6% of the Milky Way (and it is not clear which is larger) and all three are independent galaxies. Each of them contains more than a billion solar masses of material.
Elliptical galaxies M32 and M110. They may be "only" satellites of Andromeda, but they each have more than a billion stars, and they may even be more massive than numbers 5, 6, and 7.

So, the main thing

When the last star goes out tens of quadrillions of years in the future, there will still be some mass left in the galaxy. This means that this cannot be called “true death.”

All masses gravitationally interact with each other, and gravitational objects of different masses exhibit strange properties when interacting:

Repeated “approaches” and close passes cause exchanges of speed and impulses between them.
Objects with low mass are ejected from the galaxy, and objects with higher mass sink into the center, losing speed.
Over a sufficiently long period of time, most of the mass will be ejected, and only a small part of the remaining mass will be firmly attached.

But this will come to an end too?

Mythology

Armenian, Arabic, Wallachian, Jewish, Persian, Turkish, Kyrgyz

Buryat

Hungarian

Ancient Greek

Etymology of the word Galaxias (Γαλαξίας) and its connection with milk (γάλα) are revealed by two similar ancient Greek myths. One of the legends tells about the mother’s milk spilling across the sky from the goddess Hera, who was breastfeeding Hercules. When Hera learned that the baby she was nursing was not her own child, but the illegitimate son of Zeus and an earthly woman, she pushed him away, and the spilled milk became the Milky Way. Another legend says that the spilled milk was the milk of Rhea, the wife of Kronos, and the baby was Zeus himself. Kronos devoured his children because it was foretold that he would be overthrown by his own son. Rhea hatched a plan to save her sixth child, newborn Zeus. She wrapped a stone in baby clothes and slipped it to Kronos. Kronos asked her to feed her son one more time before he swallowed him. The milk spilled from Rhea's breast onto a bare rock later became known as the Milky Way.

Indian

Inca

Ketskaya

Chinese, Vietnamese, Korean, Japanese

In the mythologies of the Sinosphere, the Milky Way is called and compared to a river (in Vietnamese, Chinese, Korean and Japanese the name “silver river” is retained). The Chinese also sometimes called the Milky Way the “Yellow Road”, after the color of the straw.

Indigenous peoples of North America

Maori

Finnish, Lithuanian, Estonian, Erzya, Kazakh

The Finnish name is Finnish. Linnunrata– means “Way of the Birds”; the Lithuanian name has a similar etymology. Estonian myth also connects the Milky Way with bird flight.

The Erzya name is “Kargon Ki” (“Crane Road”).

The Kazakh name is “Kus Zholy” (“Path of the Birds”).

Interesting facts about the Milky Way galaxy

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