home Calculators Dangerous neighbor. Interesting facts about the Milky Way galaxy

Dangerous neighbor. Interesting facts about the Milky Way galaxy

Our Galaxy. Mysteries of the Milky Way

To some extent, we know more about distant star systems than about our home Galaxy - the Milky Way. It is more difficult to study its structure than the structure of any other galaxies, because it has to be studied from the inside, and many things are not so easy to see. Interstellar dust clouds absorb the light emitted by myriads of distant stars.

Only with the development of radio astronomy and the advent of infrared telescopes were scientists able to understand how our Galaxy works. But many details remain unclear to this day. Even the number of stars in the Milky Way is estimated rather roughly. The latest electronic reference books give figures from 100 to 300 billion stars.

Not so long ago, it was believed that our Galaxy has 4 large arms. But in 2008, astronomers from the University of Wisconsin published the results of processing about 800,000 infrared images that were taken by the Spitzer Space Telescope. Their analysis showed that the Milky Way has only two arms. As for the other branches, they are only narrow side branches. So, the Milky Way is a spiral galaxy with two arms. It should be noted that most spiral galaxies known to us also have only two arms.

“Thanks to the Spitzer telescope, we have the opportunity to rethink the structure of the Milky Way,” said astronomer Robert Benjamin of the University of Wisconsin, speaking at a conference of the American Astronomical Society. “We are refining our understanding of the Galaxy in the same way that centuries ago, pioneers, traveling around the globe, refined and rethought previous ideas about what the Earth looks like.”

Since the early 90s of the 20th century, observations carried out in the infrared range have increasingly changed our knowledge of the structure of the Milky Way, because infrared telescopes make it possible to look through gas and dust clouds and see what is inaccessible to conventional telescopes.

2004 - The age of our Galaxy was estimated at 13.6 billion years. It arose shortly after. At first it was a diffuse gas bubble containing mainly hydrogen and helium. Over time, it turned into the huge spiral galaxy in which we now live.

general characteristics

But how did the evolution of our Galaxy proceed? How was it formed - slowly or, on the contrary, very quickly? How did it become saturated with heavy elements? How has the shape of the Milky Way and its chemical composition changed over billions of years? Scientists have yet to provide detailed answers to these questions.

The extent of our Galaxy is about 100,000 light years, and the average thickness of the galactic disk is about 3,000 light years (the thickness of its convex part, the bulge, reaches 16,000 light years). However, in 2008, Australian astronomer Brian Gensler, after analyzing the results of observations of pulsars, suggested that the galactic disk is probably twice as thick as is commonly believed.

Is our Galaxy large or small by cosmic standards? By comparison, the Andromeda nebula, our closest large galaxy, is approximately 150,000 light years across.

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

Structure of galaxies

Black hole

So, the Milky Way is not inferior in size to the Andromeda nebula. “We should no longer think of our galaxy as the little sister of the Andromeda nebula,” said astronomer Mark Reid of the Smithsonian Center for Astrophysics at Harvard University. At the same time, since the mass of our Galaxy is greater than expected, its gravitational force is also greater, which means that the likelihood of it colliding with other galaxies in our vicinity increases.

Our Galaxy is surrounded by a spherical halo, reaching a diameter of 165,000 light years. Astronomers sometimes call the halo a “galactic atmosphere.” It contains approximately 150 globular clusters, as well as a small number of ancient stars. The rest of the halo space is filled with rarefied gas, as well as dark matter. The mass of the latter is estimated at approximately a trillion solar masses.

The spiral arms of the Milky Way contain enormous amounts of hydrogen. This is where stars continue to be born. Over time, young stars leave the arms of galaxies and “move” into the galactic disk. However, the most massive and bright stars do not live long enough, so they do not have time to move away from their place of birth. It is no coincidence that the arms of our Galaxy glow so brightly. Most of the Milky Way consists of small, not very massive stars.

The central part of the Milky Way is located in the constellation Sagittarius. This area is surrounded by dark gas and dust clouds, behind which nothing can be seen. Only since the 1950s, using radio astronomy, have scientists been able to gradually discern what lies there. In this part of the Galaxy, a powerful radio source was discovered, called Sagittarius A. As observations have shown, a mass is concentrated here that exceeds the mass of the Sun by several million times. The most acceptable explanation for this fact is only one: in the center of our Galaxy is located.

Now, for some reason, she has taken a break for herself and is not particularly active. The flow of matter here is very poor. Maybe over time the black hole will develop an appetite. Then it will again begin to absorb the veil of gas and dust that surrounds it, and the Milky Way will join the list of active galaxies. It is possible that before this, stars will begin to rapidly form in the center of the Galaxy. Similar processes are likely to be repeated regularly.

2010 - American astronomers, using the Fermi Space Telescope, designed to observe sources of gamma radiation, discovered two mysterious structures in our Galaxy - two huge bubbles emitting gamma radiation. The diameter of each of them is on average 25,000 light years. They fly away from the center of the Galaxy in northern and southern directions. Perhaps we are talking about streams of particles that were once emitted by a black hole located in the middle of the Galaxy. Other researchers believe that we are talking about gas clouds that exploded during the birth of stars.

There are several dwarf galaxies around the Milky Way. The most famous of them are the Large and Small Magellanic Clouds, which are connected to the Milky Way by a kind of hydrogen bridge, a huge plume of gas that stretches behind these galaxies. It was called the Magellanic Stream. Its extent is about 300,000 light years. Our Galaxy constantly absorbs the dwarf galaxies closest to it, in particular the Sagitarius Galaxy, which is located at a distance of 50,000 light years from the galactic center.

It remains to add that the Milky Way and the Andromeda nebula are moving towards each other. Presumably, after 3 billion years, both galaxies will merge together, forming a larger elliptical galaxy, which has already been called Milkyhoney.

Origin of the Milky Way

Andromeda's nebula

For a long time it was believed that the Milky Way formed gradually. 1962 - Olin Eggen, Donald Linden-Bell and Allan Sandage proposed a hypothesis that became known as the ELS model (named after the initial letters of their last names). According to it, a homogeneous cloud of gas once slowly rotated in place of the Milky Way. It resembled a ball and reached approximately 300,000 light years in diameter, and consisted mainly of hydrogen and helium. Under the influence of gravity, the protogalaxy shrank and became flat; at the same time, its rotation noticeably accelerated.

For almost two decades, this model suited scientists. But new observational results show that the Milky Way could not have arisen in the way theorists predicted.

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

Globular clusters have been discovered in both the galactic disk and halo that are younger than the ELS model allows. Obviously, they are absorbed by our late Galaxy.

Many stars in the halo rotate in a different direction than the Milky Way. Maybe they, too, were once outside the Galaxy, but then they were drawn into this “stellar vortex” - like a random swimmer in a whirlpool.

1978 - Leonard Searle and Robert Zinn proposed their model of the formation of the Milky Way. It was designated as "Model SZ". Now the history of the Galaxy has become noticeably more complicated. Not so long ago, its youth, in the opinion of astronomers, was described as simply as in the opinion of physicists - rectilinear translational motion. The mechanics of what was happening were clearly visible: there was a homogeneous cloud; it consisted only of evenly spread gas. Nothing by its presence complicated the theorists' calculations.

Now, instead of one huge cloud in the visions of scientists, several small, intricately scattered clouds appeared at once. Stars were visible among them; however, they were located only in the halo. Inside the halo everything was seething: clouds collided; gas masses were mixed and compacted. Over time, a galactic disk was formed from this mixture. New stars began to appear in it. But this model was subsequently criticized.

It was impossible to understand what connected the halo and the galactic disk. This condensed disk and the sparse stellar shell around it had little in common. After Searle and Zinn compiled their model, it turned out that the halo rotates too slowly to form a galactic disk. Judging by the distribution of chemical elements, the latter arose from protogalactic gas. Finally, the angular momentum of the disk turned out to be 10 times higher than the halo.

The whole secret is that both models contain a grain of truth. The trouble is that they are too simple and one-sided. Both now seem to be fragments of the same recipe that created the Milky Way. Eggen and his colleagues read a few lines from this recipe, Searle and Zinn read a few others. Therefore, trying to re-imagine the history of our Galaxy, we now and then notice familiar lines that we have already read once.

Milky Way. Computer model

So it all started shortly after the Big Bang. “Today it is generally accepted that fluctuations in the density of dark matter gave rise to the first structures - the so-called dark halos. Thanks to the force of gravity, these structures did not disintegrate,” notes German astronomer Andreas Burkert, author of a new model of the birth of the Galaxy.

Dark halos became embryos - nuclei - of future galaxies. Gas accumulated around them under the influence of gravity. A homogeneous collapse occurred, as described by the ELS model. Already 500-1000 million years after the Big Bang, gas accumulations surrounding dark halos became “incubators” of stars. Small protogalaxies appeared here. The first globular clusters arose in dense clouds of gas, because stars were born here hundreds of times more often than anywhere else. Protogalaxies collided and merged with each other - this is how large galaxies were formed, including our Milky Way. Today it is surrounded by dark matter and a halo of single stars and their globular clusters, ruins of a universe more than 12 billion years old.

There were many very massive stars in the protogalaxies. Less than a few tens of millions of years passed before most of them exploded. These explosions enriched the gas clouds with heavy chemical elements. Therefore, the stars that were born in the galactic disk were not the same as in the halo - they contained hundreds of times more metals. In addition, these explosions generated powerful galactic vortices that heated the gas and swept it beyond the protogalaxies. A separation of gas masses and dark matter occurred. This was the most important stage in the formation of galaxies, not previously taken into account in any model.

At the same time, dark halos increasingly collided with each other. Moreover, the protogalaxies stretched out or disintegrated. These catastrophes are reminiscent of the chains of stars preserved in the halo of the Milky Way since the days of “youth”. By studying their location, it is possible to assess the events that took place in that era. Gradually, these stars formed a vast sphere - the halo we see. As it cooled, gas clouds penetrated inside it. Their angular momentum was conserved, so they did not collapse into one single point, but formed a rotating disk. All this happened more than 12 billion years ago. The gas was now compressed as described in the ELS model.

At this time, the “bulge” of the Milky Way is formed - its middle part, reminiscent of an ellipsoid. The bulge is made up of very old stars. It probably arose during the merger of the largest protogalaxies that held gas clouds for the longest time. In the middle of it were neutron stars and tiny black holes - relics of exploding supernovae. They merged with each other, simultaneously absorbing gas streams. Perhaps this is how the huge black hole that now resides in the center of our Galaxy was born.

The history of the Milky Way is much more chaotic than previously thought. Our native Galaxy, impressive even by cosmic standards, was formed after a series of impacts and mergers - after a series of cosmic disasters. Traces of those ancient events can still be found today.

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

In addition, the Milky Way attracts huge masses of gas. Thus, in 1958, Dutch astronomers noticed many small spots in the halo. In fact, they turned out to be gas clouds, which consisted mainly of hydrogen atoms and were rushing towards the galactic disk.

Our Galaxy will not restrain its appetite in the future. Perhaps it will absorb the dwarf galaxies closest to us - Fornax, Carina and, probably, Sextans, and then merge with the Andromeda nebula. Around the Milky Way – this insatiable “stellar cannibal” – it will become even more deserted.

Milky Way- the galaxy that is most important for humans because it is their home. But when it comes to research, our galaxy becomes an unremarkable average spiral galaxy, like billions of other galaxies scattered throughout the Universe.

Looking at the night sky, outside of city illumination, you can clearly see a wide bright stripe running across the entire sky. The ancient inhabitants of the Earth called this bright object, formed long before the formation of the Earth, a river, a road, and other names with similar meanings. In reality, this is nothing more than the center of our galaxy, visible from one of its arms.

Structure of the Milky Way galaxy

The Milky Way is a type of barred spiral galaxy measuring about 100,000 light years in diameter. If we were able to look at it from above, we would be able to see a central bulge surrounded by four large spiral arms that wrap around the central area. Spiral galaxies are the most common and make up approximately two-thirds of all galaxies known to mankind.

Unlike an ordinary spiral, a barred spiral galaxy contains a kind of “bridge” running through its central region and two main spirals. In addition, in the inner part there is another pair of sleeves, which at a certain distance transform into a four-arm structure. Our solar system is located in one of the small arms known as the Orion arm, which is located between the large Perseus and Sagittarius arms.

The Milky Way does not stand still. It constantly rotates around its center. Thus, the arms are constantly moving in space. Our Solar System, along with the Orion Arm, moves at a speed of approximately 828,000 kilometers per hour. Even moving at such tremendous speed, the solar system would take about 230 million years to complete one revolution around the Milky Way.

Interesting facts about the Milky Way galaxy

The history of the Milky Way galaxy begins its journey shortly after the Big Bang;
The Milky Way contains some of the earliest stars in the Universe;
The Milky Way has joined other galaxies in the distant past. Our galaxy is currently increasing its size by attracting material from the Magellanic Clouds;
The Milky Way moves through space at a speed of 552 kilometers per second;
At the center of the Milky Way there is a supermassive black hole called Sgr A* with a mass of about 4.3 million solar masses;
The stars, gas and dust of the Milky Way move around the center at a speed of about 220 kilometers per second. The constancy of this speed for all stars, regardless of their distance to the galactic core, indicates the existence of mysterious dark matter;

The spiral arms that curve around the center of the galaxy contain large amounts of dust and gas, from which new stars are subsequently formed. These arms form what astronomers call the disk of the galaxy. Its thickness compared to the diameter of the galaxy is small and is about 1000 light years.

At the center of the Milky Way is the galactic core. It is full of dust, gas and stars. The Milky Way's core is the reason we only see a small fraction of all the stars in our galaxy. The dust and gas in it are so dense that scientists are simply unable to see what is in the center.

Recent research by scientists confirms the fact that at the center of the Milky Way there is a supergiant black hole, the mass of which is comparable to the mass of ~4.3 million solar masses. At the very beginning of history, this supermassive black hole could have been much smaller, but large reserves of dust and gas allowed it to grow to such a huge size.

Although black holes cannot be detected by direct observation, astronomers can see them due to gravitational effects. According to scientists, most galaxies in the Universe contain a supermassive black hole at their center.

The central core and spiral arms are not the only constituent elements of the Milky Way spiral galaxy. Our galaxy is surrounded by a spherical halo of hot gas, old stars and globular clusters. Although the halo extends over hundreds of thousands of light years, it contains approximately 2 percent more stars than those located in the galaxy's disk.

Dust, gas and stars are the most visible components of our galaxy, but the Milky Way contains another, as yet elusive, component - dark matter. Astronomers cannot yet directly detect it, but they can talk about its presence, just as in the case of black holes, through indirect signs. Recent research in this area shows that 90% of the mass of our galaxy comes from elusive dark matter.

The future of the Milky Way galaxy

The Milky Way not only revolves around itself, but also moves through the Universe. Even though space is a relatively empty place, there may be dust, gas and other galaxies along the way. Our galaxy is also not immune to a chance encounter with another massive cluster of stars.

In about 4 billion years, the Milky Way will collide with its nearest neighbor, the Andromeda Galaxy. Both galaxies are rushing towards each other at a speed of approximately 112 km/s. After the collision, both galaxies will provide a new influx of stellar material, which will lead to a new wave of star formation.

Fortunately, the inhabitants of the Earth are not very worried about this fact. By that time, our Sun will turn into a red giant and life on our planet will be impossible.

Useful articles that will answer most interesting questions about the Milky Way galaxy.

Deep space objects

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

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

History of discovery

Galileo's discovery

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

William Herschel's discovery

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

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

What shape does the Milky Way have?

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

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

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

Such stars have several features:

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

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

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

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

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

Structure of the Milky Way

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

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

The disk itself is divided into the following parts:

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

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

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

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

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

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

The Sun's Place in the Galaxy

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

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

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

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

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

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

Location of stars

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

What will the death of the Milky Way look like?

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

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

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

So, the main thing

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

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

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

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

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

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

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

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

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

But this will come to an end too?

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

Mythology

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

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

Buryat

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

Hungarian

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

Ancient Greek

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

Indian

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

Inca

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

Ketskaya

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

Chinese, Vietnamese, Korean, Japanese

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

Indigenous peoples of North America

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

Maori

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

Finnish, Lithuanian, Estonian, Erzya, Kazakh

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

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

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

Interesting facts about the Milky Way galaxy

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

The cosmos that we are trying to study is a huge and endless space in which there are tens, hundreds, thousands of trillions of stars, united in certain groups. Our Earth does not live on its own. We are part of the solar system, which is a small particle and part of the Milky Way, a larger cosmic formation.

Our Earth, like the other planets of the Milky Way, our star called the Sun, like other stars of the Milky Way, move in the Universe in a certain order and occupy designated places. Let's try to understand in more detail what is the structure of the Milky Way, and what are the main features of our galaxy?

Origin of the Milky Way

Our galaxy has its own history, like other areas of outer space, and is the product of a catastrophe on a universal scale. The main theory of the origin of the Universe that dominates the scientific community today is the Big Bang. A model that perfectly characterizes the Big Bang theory is a nuclear chain reaction at the microscopic level. Initially, there was some kind of substance that, for certain reasons, instantly began to move and exploded. There is no need to talk about the conditions that led to the onset of the explosive reaction. This is far from our understanding. Now the Universe, formed 15 billion years ago as a result of a cataclysm, is a huge, endless polygon.

The primary products of the explosion initially consisted of accumulations and clouds of gas. Subsequently, under the influence of gravitational forces and other physical processes, the formation of larger objects on a universal scale occurred. Everything happened very quickly by cosmic standards, over billions of years. First there was the formation of stars, which formed clusters and later merged into galaxies, the exact number of which is unknown. In its composition, galactic matter is atoms of hydrogen and helium in the company of other elements, which are the building material for the formation of stars and other space objects.

It is not possible to say exactly where in the Universe the Milky Way is located, since the exact center of the universe is unknown.

Due to the similarity of the processes that formed the Universe, our galaxy is very similar in structure to many others. By its type, it is a typical spiral galaxy, a type of object that is widespread in the Universe. In terms of its size, the galaxy is in the golden mean - neither small nor huge. Our galaxy has many more smaller stellar neighbors than those of colossal size.

The age of all galaxies that exist in outer space is also the same. Our galaxy is almost the same age as the Universe and is 14.5 billion years old. Over this enormous period of time, the structure of the Milky Way has changed several times, and this is still happening today, only imperceptibly, in comparison with the pace of earthly life.

There is a curious story about the name of our galaxy. Scientists believe that the name Milky Way is legendary. This is an attempt to connect the location of the stars in our sky with the ancient Greek myth about the father of the gods Kronos, who devoured his own children. The last child, who faced the same sad fate, turned out to be thin and was given to a nurse to be fattened. During feeding, splashes of milk fell on the sky, thereby creating a milk trail. Subsequently, scientists and astronomers of all times and peoples agreed that our galaxy is indeed very similar to a milk road.

The Milky Way is currently in the middle of its development cycle. In other words, the cosmic gas and material to form new stars is running out. The existing stars are still quite young. As in the story with the Sun, which may turn into a Red Giant in 6-7 billion years, our descendants will observe the transformation of other stars and the entire galaxy as a whole into the red sequence.

Our galaxy may cease to exist as a result of another universal cataclysm. Research topics in recent years are focused on the upcoming meeting of the Milky Way with our closest neighbor, the Andromeda galaxy, in the distant future. It is likely that the Milky Way will break up into several small galaxies after meeting the Andromeda Galaxy. In any case, this will be the reason for the emergence of new stars and the reorganization of the space closest to us. We can only guess what the fate of the Universe and our galaxy will be in the distant future.

Astrophysical parameters of the Milky Way

In order to imagine what the Milky Way looks like on a cosmic scale, it is enough to look at the Universe itself and compare its individual parts. Our galaxy is part of a subgroup, which in turn is part of the Local Group, a larger formation. Here our cosmic metropolis neighbors the Andromeda and Triangulum galaxies. The trio is surrounded by more than 40 small galaxies. The local group is already part of an even larger formation and is part of the Virgo supercluster. Some argue that these are only rough guesses about where our galaxy is located. The scale of the formations is so enormous that it is almost impossible to imagine it all. Today we know the distance to the nearest neighboring galaxies. Other deep space objects are out of sight. Their existence is only theoretically and mathematically allowed.

The location of the galaxy became known only thanks to approximate calculations that determined the distance to its nearest neighbors. The Milky Way's satellites are dwarf galaxies - the Small and Large Magellanic Clouds. In total, according to scientists, there are up to 14 satellite galaxies that form the escort of the universal chariot called the Milky Way.

As for the visible world, today there is enough information about what our galaxy looks like. The existing model, and with it the map of the Milky Way, is compiled on the basis of mathematical calculations, data obtained as a result of astrophysical observations. Each cosmic body or fragment of the galaxy takes its place. It’s like in the Universe, only on a smaller scale. The astrophysical parameters of our cosmic metropolis are interesting, and they are impressive.

Our galaxy is a barred spiral galaxy, which is designated on star maps by the index SBbc. The diameter of the galactic disk of the Milky Way is about 50-90 thousand light years or 30 thousand parsecs. For comparison, the radius of the Andromeda galaxy is 110 thousand light years on the scale of the Universe. One can only imagine how much larger our neighbor is than the Milky Way. The sizes of the dwarf galaxies closest to the Milky Way are tens of times smaller than those of our galaxy. Magellanic clouds have a diameter of only 7-10 thousand light years. There are about 200-400 billion stars in this huge stellar cycle. These stars are collected in clusters and nebulae. A significant part of it is the arms of the Milky Way, in one of which our solar system is located.

Everything else is dark matter, clouds of cosmic gas and bubbles that fill interstellar space. The closer to the center of the galaxy, the more stars there are, the more crowded outer space becomes. Our Sun is located in a region of space consisting of smaller space objects located at a considerable distance from each other.

The mass of the Milky Way is 6x1042 kg, which is trillions of times more than the mass of our Sun. Almost all the stars inhabiting our stellar country are located in the plane of one disk, the thickness of which, according to various estimates, is 1000 light years. It is not possible to know the exact mass of our galaxy, since most of the visible spectrum of stars is hidden from us by the arms of the Milky Way. In addition, the mass of dark matter, which occupies vast interstellar spaces, is unknown.

The distance from the Sun to the center of our galaxy is 27 thousand light years. Being on the relative periphery, the Sun rapidly moves around the center of the galaxy, completing a full revolution every 240 million years.

The center of the galaxy has a diameter of 1000 parsecs and consists of a core with an interesting sequence. The center of the core has the shape of a bulge, in which the largest stars and a cluster of hot gases are concentrated. It is this region that releases a huge amount of energy, which in total is greater than that emitted by the billions of stars that make up the galaxy. This part of the core is the most active and brightest part of the galaxy. At the edges of the core there is a bridge, which is the beginning of the arms of our galaxy. Such a bridge arises as a result of the colossal gravitational force caused by the rapid speed of rotation of the galaxy itself.

Considering the central part of the galaxy, the following fact appears paradoxical. Scientists for a long time could not understand what is in the center of the Milky Way. It turns out that in the very center of a star country called the Milky Way there is a supermassive black hole, the diameter of which is about 140 km. It is there that most of the energy released by the galactic core goes; it is in this bottomless abyss that stars dissolve and die. The presence of a black hole at the center of the Milky Way indicates that all processes of formation in the Universe must end someday. Matter will turn into antimatter and everything will happen again. How this monster will behave in millions and billions of years, the black abyss is silent, which indicates that the processes of absorption of matter are only gaining strength.

The two main arms of the galaxy extend from the center - the Shield of the Centaur and the Shield of Perseus. These structural formations received their names from the constellations located in the sky. In addition to the main arms, the galaxy is surrounded by 5 more minor arms.

Near and distant future

The arms, born from the core of the Milky Way, unwind in a spiral, filling outer space with stars and cosmic material. An analogy with cosmic bodies that revolve around the Sun in our star system is appropriate here. A huge mass of stars, large and small, clusters and nebulae, cosmic objects of various sizes and natures, spins on a giant carousel. All of them create a wonderful picture of the starry sky, which people have been looking at for thousands of years. When studying our galaxy, you should know that the stars in the galaxy live according to their own laws, being today in one of the arms of the galaxy, tomorrow they will begin their journey in the other direction, leaving one arm and flying to another.

Earth in the Milky Way galaxy is far from the only planet suitable for life. This is just a particle of dust, the size of an atom, which is lost in the vast star world of our galaxy. There can be a huge number of such Earth-like planets in the galaxy. It is enough to imagine the number of stars that in one way or another have their own stellar planetary systems. Other life may be far away, at the very edge of the galaxy, tens of thousands of light years away, or, conversely, present in neighboring areas that are hidden from us by the arms of the Milky Way.

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

Star Riddle

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

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

Scientific assumptions

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

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

Galileo's discovery

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

William Herschel's discovery

Structure of galaxies

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

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

general characteristics

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

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

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

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

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

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

Core

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

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

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

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

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

Jumper

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

Disk

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

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

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

Five spiral arms

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

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

Crown

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

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

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

Location of stars

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

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

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

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

Forecast for the future

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

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