What is the name of our galaxy and what does it look like? The names of the stars in our galaxy

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.

Galaxy Plane and Plane 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 only the ordinary visible (luminous) matter contained in them is taken into account. 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. At the same time, the amount of invisible matter should be about six times greater than the amount of visible matter (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.

How many of you can confidently answer the question, what is a galaxy?

Most vaguely imagine that this concept is somehow connected with the stars and space, that the galaxy is large, and you can travel through it, as heroes of numerous films and books do with success.

What does the word "galaxy" mean?

The word "galaxy" came to us from Greek, from the word "galactikos", meaning "milky". It refers to the giant spiral star cluster to which it belongs and which we call the Milky Way.

Our galaxy from Earth can be seen in the sky as an elongated band strewn with stars, but in fact it has the shape of a disk with several twisted spiral arms.

Other galaxies can also be seen in the sky, but to distinguish them from stars and to see these clusters of stars in more detail for a person is available only with the help of powerful telescopes.

In ancient times, the Milky Way was considered sacred by our ancestors: although each nation had its own legends and myths about it, nevertheless, almost everyone recognized its exceptional importance in the picture of the universe.

Few people today know that Christmas tree- this is a reflection in our reality of the World Tree, the trunk of which, according to the ideas of the ancestors, was the Milky Way.

What is a galaxy made of?

Both our Milky Way and all the other galaxies that astronomers can observe with telescopes are made up of a huge number of stars and star systems - the Milky Way alone has about 200 billion stars.

Our Sun is just a small and far from the brightest of its stars, moreover, located on the periphery, in one of the arms of the galaxy.

The stars are most densely located in the central part, forming a bright spherical cluster there. Scientists suggest that if you look at our galaxy from the side, then it will resemble the planet Saturn in shape - a huge radiant ball surrounded by a wide and relatively thin heterogeneous ring.

In addition to stars, there are huge clouds of gases and dust in the galaxy. Some of them emit a multi-colored glow, such as the nebula, which is located in the constellation of Orion. modern science found that new stars and star systems are formed from such nebulae over billions of years.

What is at the center of the galaxy?

One of the most mysterious places in the galaxy is its central region. Her physical properties are so different from the parts of space surrounding it that scientists could not understand the nature of this phenomenon for a long time.

Only recently it was precisely established that the central part of our galaxy is occupied by a black hole - a region of space with changed properties.

The age of our galaxy is relatively small - about 12 billion years, and the processes of star formation in its core are still actively ongoing. Many white dwarfs have been discovered there - young stars, giant accumulations of hot gas, black holes of various sizes and neutron stars.

All this together forms a gigantic, unimaginably huge cosmic “kitchen”, which continues to supply new stars to the Universe like hot cakes.

Which is bigger, the universe or the galaxy?

You should know that our galaxy, despite its size, is not alone in the universe. Today, more than a hundred other galaxies are reliably known to astronomers.

Some of them are located relatively close to ours and can be discerned even with the naked eye, such as the galaxy in the constellation Coma Berenices. Others can only be seen with the observatory's powerful telescope. The third is only distinguishable from orbital station where the atmosphere does not interfere with space observation.

The universe, according to scientists, is infinite, and it contains an infinite number of galaxies. Some are born from clouds of hot gas and dust, others are in the same state as our Milky Way, and others fade away, having exhausted their energy.

There is still no unified theory explaining the origin of the Universe and the formation of stars and galaxies in it. Perhaps in the distant future, humanity will have this knowledge, but for now we can only build the most fantastic guesses about it.

> Milky Way

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

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

If you have a place away from the city, where darkness reigns and a beautiful view of the starry sky opens up, you may notice a faint light streak. This is a group with millions of small bright lights and luminous halos. Stars in front of you galaxy milky way.

But what does she represent? Let's start with the fact that the Milky Way is a spiral type of barred galaxy, on the territory of which the solar system lives. It is difficult to call the native galaxy something unique, because there are hundreds of billions of galaxies in the Universe, and many 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 that continue to exist. These are the oldest stars in the galaxy;
The galaxy has increased its parameters by absorbing and merging with others. Now she is picking stars from the Sagittarius Dwarf Galaxy and the Magellanic Clouds;
The Milky Way moves in space with an acceleration of 550 km / s with respect to the background radiation;
Lurking at the galactic center is the supermassive black hole Sagittarius A*. By mass, it is 4.3 million times greater than the solar one;
Gas, dust and stars revolve around the center at a speed of 220 km/s. This is a stable indicator, implying the presence of a shell of dark matter;
In 5 billion years, a collision with the Andromeda galaxy is expected. Some believe that the Milky Way is a double system of a giant spiral;

Discovery and naming of the Milky Way galaxy

Our galaxy, the Milky Way, has a rather interesting name, as the hazy haze resembles a milk trail. 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, so they appear to be spots. The color resembles milk ... ". Admire the 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 constructions and accurate data on the structure, on the basis of which an idea is formed of the appearance of the galactic center and arms).

Scientists thought the Milky Way was filled with stars, but that was just a guess until 1610. That's when Galileo Galilei points the first telescope into the sky and sees individual stars. It also revealed to people a new truth: 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 held together by a common gravity. The gravitational force causes objects to rotate and flatten into a disc shape. In 1785, William Herschel tried to recreate the galactic shape, but did not realize that most of it is hidden behind a dust and gas haze.

The situation changes in the 1920s. Edwin Hubble was able to convince that we see not spiral nebulae, but individual galaxies. It was then that it became possible to realize the form of ours. From that moment it became clear that this is a barred spiral galaxy. Watch the video to study 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 look 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 is quickly recognizable in the sky due to the wide and elongated white line resembling a milk trail. Interestingly, this stellar group has been available for review since the formation of the planet. In fact, this area acts as the galactic center.

The galaxy spans 100,000 light-years in diameter. If you could 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 universal galaxies.

Unlike the usual spiral, barred specimens accommodate a rod in the center with two branches. Our galaxy has two main arms and two minor arms. 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 it takes 230 million years to make one pass.

A lot of dust and gas accumulate in spiral arms, which creates excellent conditions to form new stars. The arms radiate from a galactic disk that spans roughly 1,000 light-years.

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

Hidden in the very center is a supermassive black hole, billions of times the mass of 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 it even sucks the stars. 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 stretches for hundreds of thousands of light years, but contains only 2% of the stars of those 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 low level 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 hidden on the other side. You can easily locate the center of the Milky Way galaxy in the diagram below.

If you managed to break out of the Milky Way and get a perspective for a view from above, then you would see a spiral with a bar in front of you. Extends 120,000 light years and 1,000 light years wide. For many years, scientists thought they saw 4 arms, but there are only two of them: the Shield-Centaurus and Sagittarius.

The arms are created by dense waves rotating around the galaxy. They move around the area, so they squeeze 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. We had a hard time understanding 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 figure below, you can easily understand where the solar system is located in the Milky Way galaxy.

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

Approximately 90% of the galactic mass goes into dark matter. No one can ever explain what we are facing. In principle, it has not yet been seen, but we know about the presence due to the rapid galactic rotation and other influences. It is she who keeps the galaxies from destruction during rotation. Watch the video to learn more about the stars in the Milky Way.

The stellar population of the galaxy

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

The 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. It is not worth complaining about the remoteness, because a supermassive black hole (Sagittarius A *) lurks in the central part.

Our Sun star takes 240 million years to circle the galaxy (a space year). This sounds incredible, because the last time the Sun was in the area, dinosaurs roamed the Earth. During its entire existence, the star has 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.

According to calculations, 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. In general, Andromeda is not the most accurate racer, as it has already crashed into other galaxies in the past (a noticeable large dust ring in the center).

But earthlings should not worry about the future event. After all, by that time the Sun will have exploded and destroyed our planet.

What's next for the Milky Way galaxy?

The Milky Way is believed to have come into being from a merger of smaller galaxies. This process continues as the Andromeda galaxy is already rushing towards us in order 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) contains 100 groups and galaxy clusters.

If you have not been able to admire your native galaxy, then do it as soon as possible. Find a quiet and dark place with an open sky and just enjoy this amazing star collection. Recall 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 on your own if you decide to buy a telescope.

The position and movement of the Milky Way

Our solar system, all the stars that are visible in the night sky, and many more make up the system - galaxy. There are millions of such systems (galaxies) in outer space. Our Galaxy, or the Milky Way galaxy, is a spiral galaxy with a bar (bar) of bright stars.

What does it mean? A bar of bright stars emerges from the center of the Galaxy and crosses the Galaxy in the middle. In such galaxies, the spiral arms start at the ends of the bars, while in ordinary spiral galaxies they emerge directly from the core. Look at the picture "Computer Model of the Milky Way Galaxy".

If you're wondering why our galaxy got the name "Milky Way", then listen to the ancient Greek legend.
Zeus, the god of the sky, thunder and lightning, who is in charge of the whole world, decided to make his son Hercules, born of a mortal woman, immortal. To do this, he placed the baby on his sleeping wife Hera so that Hercules would drink the divine milk. Hera, waking up, saw that she was not feeding her own child, and pushed him away from her. A jet of milk splashed from the breast of the goddess turned into the Milky Way.
Of course, this is just a legend, but the Milky Way is visible in the sky as a hazy band of light that stretches across the sky - an artistic image created by ancient people is quite justified.
When we talk about our Galaxy, we capitalize this word. When we are talking about other galaxies - we write with a capital letter.

The structure of our galaxy

The diameter of the Galaxy is about 100,000 light years (a unit of length equal to the distance traveled by light in one year, a light year is 9,460,730,472,580,800 meters).
The galaxy contains between 200 and 400 billion stars. Scientists believe that most of the mass of the Galaxy is contained not in stars and interstellar gas, but in non-luminous halo from dark matter. Halo- this is an invisible component of the galaxy, having a spherical shape and extending beyond its visible part. Mainly composed of rarefied hot gas, stars and dark matter, it makes up the bulk of the galaxy. Dark matter is a form of matter that does not emit electromagnetic radiation and does not interact with it. This property of this form of matter makes it impossible to directly observe it.
In the middle part of the Galaxy there is a bulge called bulge. If we could look at our Galaxy from the side, we would see this thickening in its center, similar to two yolks in a frying pan, if you put them together with their lower bases - look at the picture.

There is a strong concentration of stars in the central part of the Galaxy. The galactic bar is thought to be about 27,000 light-years long. This bridge passes through the center of the Galaxy at an angle of ~ 44º to the line between our Sun and the center of the Galaxy. It consists predominantly of red stars, which are considered very old. The jumper is surrounded by a ring. This ring contains most of the Galaxy's molecular hydrogen and is an active star-forming region in our Galaxy. If we observe from the Andromeda galaxy, then the galactic bar of the Milky Way would be a bright part of it.
All spiral galaxies, including our own, have spiral arms in the plane of the disk: two arms starting at a bar in the inner part of the Galaxy, and in the inner part there are a couple more arms. Then these arms pass into the four-arm structure observed in the line of neutral hydrogen in the outer parts of the Galaxy.

Discovery of the Galaxy

At first it was discovered theoretically: astronomers have already learned that the Moon revolves around the Earth, the satellites of the giant planets form systems. The earth and other planets revolve around the sun. Then a natural question arose: is the Sun also included in a system of even larger size? The first systematic study of this issue was carried out in the 18th century. English astronomer William Herschel. In accordance with his observations, he guessed that all the stars we observe form a giant star system that is flattened towards the galactic equator. For a long time it was believed that all objects in the universe are parts of our Galaxy, although even Kant suggested that some nebulae may be other galaxies, similar to the Milky Way. This hypothesis of Kant was finally proved only in the 1920s, when Edwin Hubble measured the distance to some spiral nebulae and showed that, by their distance, they cannot be part of the Galaxy.

Where in the galaxy are we?

Our solar system is located closer to the edge of the galactic disk. Together with other stars, the Sun revolves around the center of the Galaxy at a speed of 220-240 km / s, making one revolution in about 200 million years. Thus, for the entire time of its existence, the Earth flew around the center of the Galaxy no more than 30 times.
The spiral arms of the Galaxy rotate at a constant angular velocity, like spokes in wheels, and the movement of stars occurs with a different pattern, so almost all the stars of the disk either fall into the spiral arms or fall 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 us earthlings, this is very important, because violent processes take place in the spiral arms, which form powerful radiation that is destructive to all living things. No atmosphere could protect him. But our planet exists in a relatively quiet place in the Galaxy and has not been affected by these cosmic cataclysms. That is why life was able to be born and survive on Earth - the Creator chose a peaceful place for our cradle of the Earth.
Our galaxy is in Local group of galaxies- a gravitationally bound group of galaxies, including the Milky Way galaxy, the Andromeda galaxy (M31) and the Triangulum galaxy (M33), you can see this group in the picture.

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).

Discovery history

Discovery of Galileo

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 is a real cluster of stars, which, when viewed with the naked eye, merged into a continuous faintly twinkling band. Galileo even succeeded in explaining the heterogeneity of the structure of this band. It was caused by the presence in the celestial phenomenon of not only star clusters. There are also dark clouds. The combination of these two elements creates an amazing image of the night phenomenon.

Discovery of William Herschel

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

It was not until the 1920s that the work of Jacobus Kaptein saw the light of day, in which the Milky Way was described in the most detailed way. At the same time, the author gave a scheme of the star island, which is as similar as possible to the one that is known to us at the present time. Today we know that the Milky Way is a Galaxy, which includes the solar system, the Earth and those individual stars that are visible to humans with the naked eye.

What shape is the Milky Way?

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 probably a spiral galaxy.

In the 1930s, R. J. Trumpler realized that the estimates of the size of the Milky Way galaxy made by Kapetin and others were erroneous, because the measurements were based on observations using radiation waves in the visible region of the spectrum. Trumpler came to the conclusion that a 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, in order to accurately image the stars and star clusters within 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. To do this, we used the marking of stars by analogy with marks when measuring distances. Astronomers realized that O and B stars could serve to achieve this goal.

Such stars have several features:

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

Astronomers can use radio telescopes to accurately match the positions of O and B stars and, based on the 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 you see when you mix cake batter. electric mixer. These density waves are thought to have caused the spiral character of the galaxy.

Thus, by examining the sky at different wavelengths (radio, infrared, visible, ultraviolet, X-ray) using various ground-based and space telescopes, one can obtain various images of the Milky Way.

Doppler effect. Just as the high pitched sound of a fire truck siren gets lower as the vehicle moves away, the movement of the stars affects the wavelengths of light that reach Earth from them. 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 indicates how fast the star is moving relative to us. In addition, the direction of the Doppler shift can show us the direction in which the star is moving. If the star's spectrum 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 consider 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 - areas around the nucleus, including directly the areas above and below the plane of the disk.
Spiral arms are areas that protrude 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 much 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 a few thousand light-years of the center of the Galaxy is called bulge(translated from English "thickening"). The halo as a whole rotates very slowly.

Compared to halo disk spins much faster. It looks like two plates folded at the edges. The diameter of the disk of the Galaxy is about 30 kpc (100,000 light years). The thickness is about 1000 light years. Rotation speed is not the same different distances from the center. It rapidly 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 the mass of the Sun (1.99*1030 kg). Young stars and star clusters are concentrated in the disk. There are many bright and hot stars among them. The gas in the disk of the Galaxy is unevenly distributed, forming giant clouds. Main chemical element in our galaxy is hydrogen. About 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 of the central regions of the Galaxy is completely hidden from us by powerful layers of absorbing matter. Therefore, it began to be studied only after the creation of receivers for infrared and radio radiation, which is 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, regions of ionized hydrogen and numerous sources of infrared radiation are noted, indicating star formation taking place there. At 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, the youngest stars are mainly concentrated, many open star clusters, as well as chains of dense clouds of interstellar gas in which stars continue to form. In contrast to the halo, where any manifestations of stellar activity are extremely rare, a stormy 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, which are concentrated along long spirals. By modern ideas, spiral arms are associated with compression waves propagating across the disk of the galaxy. Passing through the compression regions, the matter of the disk becomes denser, and the formation of stars from the gas becomes more intense. The reasons for the appearance of such a peculiar wave structure in the disks of spiral galaxies are not entirely clear. Many astrophysicists are working on this problem.

The place of the sun in the galaxy

In the vicinity of the Sun, it is possible to trace sections of two spiral branches that are about 3 thousand light years away from us. According to the constellations where these areas are found, they are called the Sagittarius arm and the Perseus arm. The sun is almost in the middle between these spiral arms. True, relatively close (by galactic standards) from us, in the constellation of Orion, there is another, not so pronounced branch, which is considered an offshoot 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 edge of the disk than to its center.

Together with all nearby stars, the Sun revolves around the center of the Galaxy at a speed of 220–240 km/s, making one revolution in about 200 million years. This means that for the entire time of its existence, the Earth flew 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 compression wave, which forms the spiral arm, moves in the given region. Such a situation is generally unusual for the Galaxy: the spiral arms rotate at a constant angular velocity, like the spokes of a wheel, while the movement of stars, as we have seen, obeys a completely different pattern. Therefore, almost the entire stellar population of the disk either gets inside the spiral branch or leaves it. 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 favorable. After all, violent processes occur in the spiral branches, generating powerful radiation, destructive for 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 experienced the influence of these cosmic cataclysms for hundreds of millions and billions of years. Perhaps that 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.

The location of the stars

On a cloudless night sky, the Milky Way is visible from anywhere on our planet. However, only a part of the Galaxy, which is a system of stars located inside the Orion arm, is accessible to the human eye. What is the Milky Way? The definition in space of all its parts becomes most understandable if we consider the star map. In this case, it becomes clear that the Sun, illuminating the Earth, is located almost on the disk. This is almost the edge of the Galaxy, where the distance from the nucleus is 26-28 thousand light years. Moving at a speed of 240 kilometers per hour, the Luminary spends 200 million years on one revolution around the core, so that for the entire time of its existence it traveled across the disk, rounding the core, only thirty times. Our planet is in the so-called corotation circle. This is a place in which the speed of rotation 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 is a small number of stars. Our Earth is such a planet. It is located on the periphery of the Galaxy, in its most peaceful place. That is why on our planet for several billion years there were no global cataclysms that 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 can blindly look around, thinking that the Milky Way, Andromeda (our older sister) and a bunch of unknowns - our cosmic neighbors - this is our home, but in reality there is much more. It's time to explore what else is around us. Go.

Triangulum Galaxy. With a mass of about 5% of that of the Milky Way, 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 is 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 give rise to new, hot and large stars in the universe.
Small Magellanic Cloud, NGC 3190 and NGC 6822. All of them have masses from 0.1% to 0.6% of the Milky Way (and it is not clear which one is larger) and all three are independent galaxies. Each contains over a billion solar masses of material.
Elliptical galaxies M32 and M110. They may be "only" satellites of Andromeda, but each of them has more than a billion stars, and they can even exceed the masses of numbers 5, 6 and 7.

In addition, there are at least 45 other known galaxies - smaller ones - that make up our local group. Each of them has a halo of dark matter surrounding it; each of them is gravitationally attached 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 tides, and this is partly true. But from the point of view of the galaxy, the tides are a less noticeable process. The part of the small galaxy that is close to the big one will be attracted with more gravitational force, and the part that is further away will experience less attraction. 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 incorporated into the large galaxies with which they merge. “So what,” you say. After all, this is not quite 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 drag the galaxies into a gravitational dance that will lead to a big 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: the Milkweeds.

A small percentage of the stars will be ejected during such a merger, but the majority will remain unharmed, 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 to gobble up the rest. This process will take place in all connected groups and clusters of galaxies throughout the Universe, while dark energy will push individual groups and clusters apart from each other. But even this cannot be called death, because the galaxy will remain. And for a while it will be. But the galaxy is made up of stars, dust and gas, and everything will eventually come to an end.

Across the Universe, galactic mergers will take place over tens of billions of years. During the same time, dark energy will pull them all over 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 inhabit each galaxy—albeit with 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 this inevitability happens, we are left with brown dwarfs (failed stars) that accidentally merge, re-ignite nuclear fusion and create starlight for tens of trillions of years.

When the last star goes out tens of quadrillion years in the future, there will still be some mass left in the galaxy. So this can not 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 momentum 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 remnants, 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 one, and since the black hole will be as large as possible, it will eat everything it can reach. At the center of Mlecomeda there will be an object hundreds of millions of times more massive than our Sun.

But will it end too?

Thanks to the phenomenon of Hawking radiation, even these objects will one day decay. It will take about 1080 to 10100 years, depending on how massive our supermassive black hole becomes as it grows, but the end is coming. After that, the remains, rotating around the galactic center, will untie 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 be nothing that we once called a local band, milky way and other dear names.

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 a 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’s road”). The myth about scattered straw is also spoken of by Arabic, Jewish, Persian, Turkish and Kyrgyz names (Kirg. samanchynyn jolu- the path of the strawman) of this phenomenon. The inhabitants of Wallachia believed that Venus stole this straw from St. Peter.

Buryat

According to Buryat mythology, good forces create the world, modify the universe. Thus, the Milky Way arose from the milk that Manzan Gurme drew from her breast and splashed out after Abai Geser, who had deceived her. According to another version, the Milky Way is a "seam of the sky" sewn up after the stars fell out of it; on it, like on a bridge, tengri walk.

Hungarian

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

ancient greek

Etymology of the word Galaxias (Γαλαξίας) and its association with milk (γάλα) reveal two similar ancient Greek myths. One of the legends tells about the mother's milk spilled across the sky of the goddess Hera, who was breastfeeding Hercules. When Hera learned that the baby she was breastfeeding 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 is the milk of Rhea, the wife of Kronos, and Zeus himself was the baby. Kronos devoured his children, as it was predicted to him that he would be overthrown by his own son. Rhea has a plan to save her sixth child, the 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 chest on a bare rock was subsequently called the Milky Way.

Indian

The ancient Indians considered the Milky Way to be the milk of an evening red cow passing through the sky. In the Rig Veda, the Milky Way is called Aryaman's Throne Road. 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 is reflected in their mythology) in the sky were the dark sections of the Milky Way - a kind of "constellation" in the terminology of Andean cultures: Lama, Lama Cub, Shepherd, Condor, Partridge, Toad, Snake, Fox; as well as the stars: the Southern Cross, the Pleiades, Lyra and many others.

Ketskaya

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

Chinese, Vietnamese, Korean, Japanese

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

Indigenous peoples of North America

The Hidatsa and the Eskimos call the Milky Way "Ash". Their myths speak 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 dirt and silt raised by the belly of a turtle floating in the sky. Eskimos from the Bering Strait - that these are the traces of the Creator Raven walking across the sky. The Cherokee believed that the Milky Way was formed when one hunter stole another's wife out of jealousy, and her dog began to eat unattended cornmeal and scattered it across the sky (the same myth is found among the Khoisan population of the Kalahari). Another myth of the same people says that the Milky Way is the trail of a dog dragging something across the sky. The Ctunah called the Milky Way "the dog's tail", 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 to be the Tama-rereti boat. The nose 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 already late, and he was far from home. There were no stars in the sky, and, fearing that Tanif might attack, Tama-rereti began to throw sparkling pebbles into the sky. The heavenly deity Ranginui liked what he was doing, and he placed the Tama-rereti boat in the sky, and turned the pebbles into stars.

Finnish, Lithuanian, Estonian, Erzya, Kazakh

The Finnish name is Fin. Linnunrata- means "The Way of the Birds"; the Lithuanian name has a similar etymology. Estonian myth also connects the Milky ("bird's") Way with bird flight.

The Erzya name is "Kargon Ki" ("Crane Road").

The Kazakh name is “Kus Zholy” (“Way 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 that continue to exist. These are the oldest stars in the galaxy;
The galaxy has increased its parameters by absorbing and merging with others. Now she is picking stars from the Sagittarius Dwarf Galaxy and the Magellanic Clouds;
The Milky Way moves in space with an acceleration of 550 km / s with respect to the background radiation;
Lurking at the galactic center is the supermassive black hole Sagittarius A*. By mass, it is 4.3 million times greater than the solar one;
Gas, dust and stars revolve around the center at a speed of 220 km/s. This is a stable indicator, implying the presence of a shell of dark matter;
In 5 billion years, a collision with the Andromeda galaxy is expected.