What is the name and appearance of our Galaxy. The name of the stars of our galaxy

Milky Way (MP) - This 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 spiral galaxies with a jumper. MP is compressed in the plane and in profile is similar to a “flying saucer”.

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

Our Galaxy has the following structure: a core, 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 1,000 light-years, in the middle part of the disk a bulge of 3,000 St. years; sleeves; spherical halo (corona) containing dwarf galaxies, globular star clusters, individual stars, groups of stars, dust and gas.

A strong concentration of stars is characteristic of the central parts of the Galaxy: in each cubic parsek near the center there are many thousands. The distances between the stars are tens and hundreds of times smaller than in the vicinity of the Sun.

The galaxy rotates, but not evenly, across the entire disk. With approaching 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, an increased concentration of dust and gas is also observed. Between the center of the Galaxy and spiral arms (branches) there is a gas ring - a mixture of gas and dust, strongly emitting in the radio and infrared range. The width of this ring is about 6 thousand light years. It is located in an area between 10,000 and 16,000 light years from the center. The gas ring contains billions of solar masses of gas and dust and is the site of active star formation.

The Galaxy has a crown, which contains globular clusters and dwarf galaxies (Big and Small Magellanic clouds and other clusters). The galactic corona also has stars and groups of stars. Some of these groups interact with globular clusters and dwarf galaxies.

The plane of the galaxy and the plane of the solar system do not coincide, but are at an angle to each other, and the planetary system of the sun rotates around the center of the galaxy in about 180–220 million Earth years — this takes us one galactic year.

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

The speed of rotation of the Sun around the center of the Galaxy almost coincides with the speed of the compaction wave forming a spiral arm. This situation is atypical for the Galaxy as a whole: spiral arms rotate at a constant angular speed, like spokes in wheels, and the movement of stars occurs with a different regularity, so almost the entire stellar population of the disk either gets inside spiral arms or sometimes 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, because in spiral arms violent processes occur, forming powerful radiation, destructive for all living things. And no atmosphere could protect from it. But our planet exists in a relatively calm place of the Galaxy and for hundreds of millions (or even billions) years has not been exposed to these cosmic cataclysms. Perhaps that is why life could be born and saved on Earth.

An analysis of the rotation of the Galaxy showed that there are large masses of non-luminous (non-radiating) matter in it, called the "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 lie in brown dwarfs, in planets of gas giants that occupy an intermediate position between stars and planets, and in dense and cold molecular clouds that have a low temperature and are inaccessible to ordinary observations. In addition, in our and other galaxies there are many bodies the size of a planet 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 "extinct" stars. According to another hypothesis, galactic space (vacuum) also contributes to the amount of dark matter. Hidden mass is not only in our Galaxy, it is in all galaxies.

The problem of dark matter in astrophysics arose when it turned out that the rotation of galaxies (including our own Milky Way) cannot be correctly described if we take into account only the usual visible (luminous) matter contained in them. In this case, all the stars of the Galaxy would have to scatter and scatter in the vastness of the Universe. In order for this not to happen (and this does not happen), the presence of additional invisible matter having a large mass is necessary. The action of this invisible mass is manifested exclusively in the gravitational interaction with visible matter. In this case, the amount of invisible matter should be approximately six times the amount of visible (information on 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 stars and space, that the galaxy is large, and you can travel through it, as heroes of numerous films and books have successfully done.

What does the word galaxy mean?

The word "galaxy" came to us from the Greek language, from the word "galacticos" meaning "milky". It denotes a giant star cluster, which has a spiral shape, to which it belongs and which we call the Milky Way.

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

In the sky you can see other galaxies, but to distinguish them from the stars and see in more detail, these star clusters are accessible to humans only using powerful telescopes.

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

Today, few people know that the New Year tree is a reflection in our reality of the World Tree, the trunk of which, according to the ancestors, was the Milky Way.

What does a galaxy consist of?

And our Milky Way, and all other galaxies that astronomers can observe with telescopes, consist 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, which is also located on the periphery, in one of the arms of the galaxy.

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, it will resemble the planet Saturn in shape - a huge shining ball surrounded by a wide and relatively thin inhomogeneous ring.

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

What is in the center of the galaxy?

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

Only recently it has been precisely established that the central part of our galaxy is occupied by a black hole - a region of space with altered 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 were discovered there - young stars, giant clusters of hot gas, black holes of various thicknesses and neutron stars.

All this together forms a gigantic, unimaginably huge space "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, astronomers are reliably aware of more than a hundred other galaxies.

Some of them are located relatively close to ours and can be distinguished even with the naked eye, such as the galaxy in the constellation Volos Veronica. Others can only be seen in the powerful telescope of the observatory. Still others are distinguishable only from the orbital station, where the atmosphere does not impede observation of space.

The universe, according to the ideas of scientists, is infinite, and it contains an infinite number of galaxies. Some are born from clouds of incandescent gas and dust, others are in the same condition as our Milky Way, others die 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 possess this knowledge, but so far we can only build the most fantastic guesses about it.

\u003e Milky Way

Milky Way - a spiral galaxy with the solar system: interesting facts, size, area, detection and name, video research, structure, location.

The Milky Way is a spiral galaxy covering an area of \u200b\u200b100,000 light-years in which the solar system is located.

If you have a place farther from the city where darkness reigns and offers a beautiful view of the starry sky, then you can notice a faint bright band. This is a group with millions of small bright lights and luminous halos. Before you are the stars milky Way galaxies.

But what does she represent? To begin with, the Milky Way is a spiral type of galaxy with a jumper on the territory of which the solar system resides. It is difficult to call the native galaxy something unique, because there are still hundreds of billions of galaxies in the Universe, many of which are similar.

Interesting facts about the Milky Way galaxy

The Milky Way began to form as a cluster of dense areas after the Big Bang. The first stars to appear were in globular clusters that continue to exist. These are the oldest stars of the galaxy;
The galaxy has increased its parameters due to absorption and merger with others. Now she is taking stars from the Dwarf galaxy Sagittarius and the Magellanic Clouds;
The Milky Way moves in space with an acceleration of 550 km / s relative to relict radiation;
In the galactic center lies a supermassive black hole Sagittarius A *. By mass 4.3 million times greater than the sun;
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 binary system of a giant spiral;

Discovery and name of the Milky Way galaxy

Our Milky Way galaxy has a rather interesting name, as the foggy haze resembles a milky trail. The name has ancient roots and is translated from Latin "Via Lactea". This name already appears in the work of Tadhir Nasir ad-Din Tusi. He wrote: “It is represented by many small and tightly grouped stars. They are located close, so they seem spots. It resembles milk in color ... ” Admire the photo of the Milky Way galaxy with its sleeves and center (of course, no one can take a photo of our galaxy, however, there are similar designs and accurate data on the structure, on the basis of which an idea of \u200b\u200bthe appearance of the galactic center and sleeves is compiled).

Scientists thought the Milky Way was filled with stars, but this remained only a hunch until 1610. It was then that Galileo Galilei directs the first telescope into the sky and sees 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 joint gravity. Gravitational force causes objects to rotate and flatten in the form of a disk. In 1785, William Herschel tried to recreate the galactic form, but did not realize that most of it was hidden behind dust and gas haze.

The situation changes in the 1920s. Edwin Hubble was able to convince 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 is a spiral galaxy with a jumper. 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: an inside look

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

The location of the Milky Way galaxy

The Milky Way in the sky is recognized quickly thanks to a wide and elongated white line resembling a milky trace. Interestingly, this star group is available for review from the moment the planet is formed. In fact, this site acts as a galactic center.

The galaxy extends over 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, 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 sleeve of Orion.

The Milky Way is not static and rotates in space, transferring 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 complete one pass.

A lot of dust and gas accumulate in the spiral arms, which creates excellent conditions for the formation of new stars. Sleeves emanate from a galactic disk spanning approximately 1000 light-years.

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

A supermassive black hole hides in the very center, exceeding the mass of the Sun by billions of times. Most likely, before it was much smaller, but a regular diet of dust and gas allowed it to grow. This is an incredible glutton, because sometimes even the stars sucks. 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 for hundreds of thousands of light years, but accommodates only 2% of the stars that are in the disk. Let's not forget about dark matter (90% of the galactic mass).

The structure and composition of the Milky Way galaxy

On observation, it is clear that the Milky Way divides the heavenly 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 does not allow us to consider the galactic center, but also to understand what is hidden on the other side. You can easily find the center of the Milky Way galaxy on the bottom diagram.

If you were able to break out of the Milky Way and get a perspective for viewing from above, then you had a spiral with a bar. Extends over 120,000 light years and 1,000 light years wide. For many years, scientists thought they saw 4 sleeves, but there were only two: the Centauri Shield and the Sagittarius.

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

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

Ground and space missions made it clear 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.

About 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 the presence due to the fast galactic rotation and other influences. It is she who keeps the galaxies from being destroyed during rotation. Watch the video to learn more about the stars of 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. You should not complain about remoteness, because in the central part there is a supermassive black hole (Sagittarius A *).

It takes 240 million years for our Sun star to fly around the galaxy (space year). It sounds incredible, because the last time the Sun was in this area, dinosaurs roamed the Earth. For all its existence, the star made about 18-20 flights. That is, she was born 18.4 space years ago, and the age of the galaxy is 61 space years.

Milky Way galaxy collision trajectory

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

It is estimated that after 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 birth of stars is activated. In general, Andromeda is not the most accurate racer, as in the past it already crashed into other galaxies (a noticeably large dust ring in the center).

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

What awaits the Milky Way Galaxy?

It is believed that the Milky Way appeared due to the merger of smaller galaxies. This process continues as the Andromeda galaxy rushes 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. In this gigantic region (110 million light-years), there are 100 groups and galactic clusters.

If you have not been able to admire your own 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 explore all the stars, clusters, nebulae and famous planets online. And our starry sky map will help you find all these celestial bodies in the sky yourself, 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 others make up the system - The galaxy. There are millions of such systems (galaxies) in outer space. Our Galaxy, or the Milky Way Galaxy, is a spiral galaxy with a jumper (bar) of bright stars.

What does it mean? A jumper of bright stars emerges from the center of the Galaxy and crosses the Galaxy in the middle. In such galaxies, spiral branches begin at the ends of the lintels, while in ordinary spiral galaxies they exit directly from the nucleus. Look at the “Computer Model of the Milky Way Galaxy” picture.

If you are interested in why our Galaxy was called the Milky Way, then listen to the ancient Greek legend.
Zeus, the god of heaven, thunder and lightning, who knows the whole world, decided to make his son Heracles, born of a mortal woman, immortal. To do this, he placed the baby in his sleeping wife, Hera, so that Hercules would drink divine milk. Hera, waking up, saw that she was not feeding her child, and pushed him away from herself. A stream of milk sprinkled from the goddess’s chest turned into the Milky Way.
Of course, this is just a legend, but the Milky Way is visible in the sky as a foggy streak of light that stretches across the sky - the artistic image created by ancient people is quite justified.
When we talk about our Galaxy, we write this word with a capital letter. When it comes to 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, the light year is 9,460,730,472,580,800 meters).
The galaxy contains from 200 to 400 billion stars. Scientists believe that most of the mass of the Galaxy is not contained 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 consists 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 observe it directly.
In the middle of the galaxy is a thickening called bulge. If we could look at our Galaxy from the side, we would see in its center this thickening, similar to two yolks in a pan, if they are folded with lower bases - look at the picture.

In the central part of the Galaxy, there is a strong concentration of stars. It is estimated that the length of the galactic bridge is about 27,000 light years. This jumper 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 mainly of red stars, which are considered very old. The jumper is surrounded by a ring. This ring contains most of the molecular hydrogen of the Galaxy and is an active region of star formation in our Galaxy. If we observe from the Andromeda galaxy, the galactic bridge of the Milky Way would be a bright part of it.
All spiral galaxies, including ours, have spiral arms in the plane of the disk: two arms starting at the bar in the inner part of the Galaxy, and in the inner part there are a couple more arms. Then these arms transform into a four-arm structure observed in the line of neutral hydrogen in the outer parts of the Galaxy.

Galaxy Discovery

At first it was discovered theoretically: astronomers have already learned that the moon revolves around the Earth, the satellites of giant planets form systems. Earth and other planets revolve around the sun. Then the natural question arose: is the Sun also not entering a larger system? The first systematic study of this issue was carried out in the XVIII century. english astronomer William Herschel. In accordance with his observations, he guessed that all the stars we observe form a giant star system, which is flattened to the galactic equator. For a long time it was believed that all objects of the Universe are parts of our Galaxy, although Kant has suggested that some nebulae may be other galaxies, like the Milky Way. This Kant hypothesis 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 are we in the galaxy?

Our solar system is located closer to the edge of the galactic disk. Together with other stars, the Sun rotates around the center of the Galaxy at a speed of 220-240 km / s, making one revolution in about 200 million years. Thus, over the entire period 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 speed, like spokes in wheels, and the movement of stars occurs with a different regularity, so almost all the stars of the disk either fall inside 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 in spiral arms violent processes occur, forming powerful radiation, destructive for all living things. No atmosphere could protect him from it. But our planet exists in a relatively calm place of the Galaxy and has not been exposed to these cosmic cataclysms. That is why life was able to be born and survive on Earth - the Creator chose a quiet place for our cradle of the Earth.
Our galaxy is included in Local group of galaxies - a gravitationally bound group of galaxies, including the Milky Way galaxy, the Andromeda galaxy (M31) and the Triangle galaxy (M33), you can see this group in the picture.

The Milky Way is a galaxy in which the Earth, the solar system and all the individual stars visible with the naked eye are located. Refers to spiral galaxies with a jumper.

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

Discovery story

Discovery of Galileo

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

The discovery of William Herschel

The study of the Milky Way continued in the 18th century. During this period, William Herschel was his most active researcher. 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 with a telescope the planet and counted them in different parts of the sky. Studies have 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 as a millstone and had an elongated irregular shape. At that, the sun was inside the given ring surrounding our world. That is how all scientists represented our Galaxy until the beginning of the last century.

It was only in the 1920s that the work of Jacobus Kaptein saw the light, in which the Milky Way was described in more detail. At the same time, the author gave a diagram of a 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, which includes the solar system, the Earth and those individual stars that are visible to the human eye.

What shape does the Milky Way have?

In the study of galaxies, Edwin Hubble classified them into various types of elliptical and spiral. Spiral galaxies are disk-shaped, inside of which are spiral arms. Since the Milky Way has a disk shape 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 other scientists were erroneous, since the measurements were based on observations using radiation waves in the visible spectrum. Trumpler concluded 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. In this regard, in order to obtain an accurate image of stars and star clusters inside the Milky Way, astronomers had to find a way to see through the dust.

The first radio telescopes were invented in the 1950s. 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, star marking was used by analogy with the markings for distance measurements. Astronomers realized that stars of spectral class O and B can serve to achieve this goal.

Such stars have several features:

brightness- they are very noticeable and often found in small groups or associations;
heat- they emit waves of different lengths (visible, infrared, radio waves);
short life time- They live about 100 million years. Given the speed with which the stars rotate in the center of the galaxy, they do not move far from the place of birth.

Astronomers can use radio telescopes to accurately compare the positions of stars of the spectral class O and B, and, guided by the Doppler shifts of the radio spectrum, determine their speed. After conducting such operations with many stars, scientists were able to release combined radio and optical maps of the spiral arms of the Milky Way. Each sleeve is named for 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), the same as you see, mixing the dough on the cake with an electric mixer. It is believed that these density waves caused the spiral nature of the galaxy.

Thus, viewing the sky in waves of different lengths (radio, infrared, visible, ultraviolet, x-ray) using various ground and space telescopes, you can get different images of the Milky Way.

Doppler effect. Just as the high-pitched siren of a fire engine becomes lower when the car moves away, the movement of the stars affects the wavelength of light that travels from them to Earth. This phenomenon is called the Doppler effect. We can measure this effect by measuring the lines in the spectrum of a star and comparing them with the spectrum of a standard lamp. The degree of Doppler shift shows how fast the star moves relative to us. In addition, the direction of the Doppler shift can show us the direction of motion of the star. If the spectrum of a star shifts to the blue end, then the star moves toward us; if in the red direction it moves away.

Milky Way Structure

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

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

The disk itself is divided into the following parts:

The core is the center of the disk;
Arcs are areas around the core, including directly 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 area that surrounds the entire galaxy. A halo consists of high temperature gas and possibly dark matter.

The halo radius is much larger than the disk and, according to some sources, reaches several hundred thousand light years. The center of symmetry of the halo of the Milky Way 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 from the center of the galaxy is called bulge (in translation from English "thickening"). The halo as a whole rotates very slowly.

Compared to halo disk rotates noticeably faster. It is like two folded plates. The diameter of the galactic disk is about 30 kpc (100,000 light years). Thickness - about 1000 light years. The rotation speed is not the same at 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 * 10 30 kg). Young stars and star clusters are concentrated in the disk. Among them are many bright and hot stars. The gas in the galactic disk is distributed unevenly, forming giant clouds. The main chemical element in our galaxy is hydrogen. About 1/4 of it consists of helium.

One of the most interesting areas of the Galaxy is considered its center, or corelocated 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 of infrared and radio emission, which is absorbed to a lesser extent. A strong concentration of stars is characteristic of the central regions of the Galaxy: there are many thousands in each cubic parsek. Closer to the center, regions of ionized hydrogen and numerous sources of infrared radiation are observed, indicating star formation taking place there. In the very center of the Galaxy, it is assumed the existence of a massive compact object - a black hole weighing about a million solar masses.

One of the most prominent formations are spiral branches (or sleeves). They gave the name to this type of objects - spiral galaxies. The youngest stars, many open star clusters, as well as chains of dense clouds of interstellar gas, in which stars continue to form, are mainly concentrated along the arms. In contrast to the halo, where any manifestations of stellar activity are extremely rare, the vibrant life in the branches continues, associated with the continuous transition of matter from interstellar space to stars and vice versa. The spiral arms of the Milky Way are largely hidden from us by absorbing matter. A detailed study of them began after the advent of radio telescopes. They made it possible to study the structure of the Galaxy from observations of radio emission from atoms of interstellar hydrogen, concentrated along long spirals. According to modern concepts, spiral arms are associated with compression waves propagating through the disk of the galaxy. Passing through the compression region, the disk material 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 the sections of two spiral branches, which are approximately 3 thousand light-years distant from us. According to the constellations where these areas are found, they are called the Sagittarius sleeve and the Perseus sleeve. The sun is almost in the middle between these spiral branches. True, comparatively close (by galactic standards) from us, in the constellation Orion, there is another, not so pronounced 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 edge of the disk than to its center.

Together with all the nearby stars, the Sun rotates around the center of the Galaxy at a speed of 220–240 km / s, making one revolution in approximately 200 million years. So, 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 almost coincides with the speed with which the compaction wave moves in this area, forming a spiral arm. This situation is generally unusual for the Galaxy: spiral branches rotate at a constant angular speed, like 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 enters the spiral branch or emerges from it. The only place where the speeds of stars and spiral branches 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. Indeed, in spiral branches violent processes occur that generate powerful radiation, destructive for all living things. And no atmosphere could protect him from it. But our planet exists in a relatively calm place of the Galaxy and for hundreds of millions and billions of years has not been affected by these cosmic cataclysms. Maybe that’s why life could be born and saved 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 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.

Star location

In a cloudless night sky, the Milky Way is visible from anywhere in the world. However, only a part of the Galaxy, which is a system of stars inside the arm of Orion, 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 core is 26-28 thousand light years. Moving at a speed of 240 kilometers per hour, the Luminos spends one million revolutions around the core for 200 million years, so for all its existence it traveled around the disk, circling 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 sleeves 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. Such a planet was our Earth. 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 have been no global disasters that often occur in the Universe.

What will the death of the Milky Way look like?

The cosmic history of the death of our galaxy begins here and now. We can blindly look around, thinking that the Milky Way, Andromeda (our elder sister) and a handful of unknowns - our cosmic neighbors - this is our home, but in fact there is much more. It's time to explore what else is around us. Go.

Triangle Galaxy. With a mass of about 5% of the mass of the Milky Way, it is the third largest galaxy in the local group. It has a spiral structure, its own satellites and can be a satellite of the Andromeda galaxy.
Big 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 from us - and it continues the process of active star formation, since tidal interactions with our galaxy lead to gas 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 a mass of 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 of them contains more than 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 in mass they can even exceed 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, not one of them will remain in a few billion years.

So the main thing

As time goes on, galaxies interact gravitationally. They not only contract due to gravitational attraction, but also interact tidally. Usually we speak of tides in the context of the moon, which draws the oceans of the earth and creates tides, and this is partly true. But from a galactic point of view, the tides are a less visible process. A part of a small galaxy that is close to a large one will be attracted with more gravitational force, and a part that is further away will experience less attraction. As a result, a small galaxy will stretch out and eventually burst under the influence of attraction.

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

A small percentage of stars will be ejected during such a merger, but most will remain unscathed, with a large burst of star formation. In the end, the rest of the galaxies in our local group will also be sucked up, and there will be one large giant galaxy that devoured the rest. This process will take place in all related groups and clusters of galaxies throughout the Universe, while dark energy will push individual groups and clusters apart. But even this cannot be called death, for the galaxy will remain. And for a while it will be so. But the galaxy is made up of stars, dust and gas, and everything will someday end.

Across the universe, galactic mergers will take tens of billions of years. During this 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 will live in them. The longest-lived stars that exist today will continue to burn their fuel for tens of trillions of years, and new stars will appear from the gas, dust and star corpses that inhabit each galaxy - although less and less.

When the last stars burn, only their corpses remain - white dwarfs and neutron stars. They will shine for hundreds of trillions or even quadrillion years before they go out. When this inevitability happens, we will have brown dwarfs (failed stars) that accidentally merge, reignite nuclear fusion and create starlight for tens of trillions of years.

When, after dozens of quadrillion years in the future, the last star goes out, there will still be some mass 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 in the interaction:

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

At the very center of these galactic remains there will be a supermassive black hole in each galaxy, and the rest of the galactic objects will revolve around an enlarged 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 that it can reach. In the center of Mlecomeda there will be an object hundreds of millions of times more massive than our Sun.

But will it also end?

Thanks to the phenomenon of Hawking radiation, even these objects will one day decay. It will take about 10 80 - 10 100 years, depending on how massive our supermassive black hole becomes in the process of growth, but the end is coming. After this, the remains orbiting around the galactic center will unleash and leave only a halo of dark matter, which can also arbitrarily 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 the heart.

Mythology

Armenian, Arab, 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 a straw from the ancestor of the Assyrians, Barsham, in harsh winter and hid in the sky. When he walked with his prey through the sky, he dropped straws on his way; from them a light trail was formed in the sky (in Armenian, “The Road of Straw Bales”). The myth of spread straw is also spoken by the Arabic, Jewish, Persian, Turkish and Kyrgyz names (Kyrgyz. samanchynyn zholu - 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. So, the Milky Way arose from milk, which Manzan Gurme poured from his chest and splashed out after Abay Geser, who deceived her. According to another version, the Milky Way is a “seam of the sky”, sewn up after the stars spilled out of it; Tengri walk on it, as if on a bridge.

Hungarian

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

Ancient greek

Etymology of the word Galaxias (Γαλαξίας) and its relationship with milk (γάλα) reveal two similar ancient Greek myths. One of the legends tells about the mother milk of the goddess Hera spilled across the sky, who was breast-feeding Heracles. When Hera found out that the baby she was breastfeeding was not her own child, but the illegitimate son of Zeus and the 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 a baby. Kronos devoured his children, as it was predicted that he would be overthrown by his own son. Rhea had a plan for saving her sixth child, the newborn Zeus. She wrapped a stone in infant clothes and slipped it to Kronos. Kronos asked her to feed her son again before he swallows it. The milk spilled from Rhea’s chest on a bare stone was later 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 Rigveda, the Milky Way is called the throne road of Aryaman. The Bhagavata Purana contains a version according to which the Milky Way is the stomach of a heavenly dolphin.

Inca

The main objects of observation in Incan astronomy (which was 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 stars: Southern Cross, Pleiades, Lyra and many others.

Ket

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

Chinese, Vietnamese, Korean, Japanese

In the mythology of the synosphere, the Milky Way is called and compared with the river (in Vietnamese, Chinese, Korean and Japanese, the name "silver river" is preserved. The Chinese also sometimes called the Milky Way "Yellow Road", the color of straw.

Indigenous peoples of north america

Hidatsa and the Eskimos call the Milky Way "Ashen." Their myths speak of a girl scattering ashes across the sky so that people can find their way home at night. The Cheyenne believed that the Milky Way is mud and silt, raised by the belly of a turtle floating in the sky. Eskimos from the Bering Strait - that these are traces of the Creator Raven walking through the sky. The Cherokee believed that the Milky Way formed when one hunter stole the wife of another from jealousy, and her dog began to eat unattended corn flour and scattered it across the sky (the same myth is found among the Khoisan population of Kalahari). Another myth of the same people says that the Milky Way is a trace of a dog dragging something through the sky. Ktunakh called the Milky Way "dog tail", black-footed called it "wolf road." The Wyandot myth suggests 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 Tama-retreti 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, once Tama-retrei was sailing in his canoe and saw that it was too late, and he was far from home. There were no stars in the sky, and, fearing that Tanifa 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-retreti boat in the sky, and turned the pebbles into stars.

Finnish, Lithuanian, Estonian, Erzyan, Kazakh

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

Erzyan name - “Cargon Ki” (“Crane Road”).

The Kazakh name is “Құs Zholy” (“Bird's Way”).

Interesting facts about the Milky Way galaxy

The Milky Way began to form as a cluster of dense areas after the Big Bang. The first stars to appear were in globular clusters that continue to exist. These are the oldest stars of the galaxy;
The galaxy has increased its parameters due to absorption and merger with others. Now she is taking stars from the Dwarf galaxy Sagittarius and the Magellanic Clouds;
The Milky Way moves in space with an acceleration of 550 km / s relative to relict radiation;
In the galactic center lies a supermassive black hole Sagittarius A *. By mass 4.3 million times greater than the sun;
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.