Our galaxy in the universe. What is the name and what does our Galaxy look like?

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

What does it mean? A bridge of bright stars emerges from the center of the Galaxy and crosses the Galaxy in the middle. In such galaxies, the spiral arms begin at the ends of the bars, whereas in ordinary spiral galaxies they extend directly from the core. Look at the picture “Computer model of the Milky Way Galaxy.”

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

The structure of our Galaxy

The diameter of the Galaxy is about 100,000 light years (a unit of length equal to the distance traveled by light in one year; a light year is equal to 9,460,730,472,580,800 meters).
The galaxy contains between 200 and 400 billion stars. Scientists believe that most of the mass of the Galaxy is contained not in stars and interstellar gas, but in non-luminous halo from dark matter. Halo- This is the invisible component of the galaxy, which has a spherical shape and extends beyond its visible part. Mainly composed of tenuous 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 or interact with electromagnetic radiation. This property of this form of matter makes its direct observation impossible.
In the middle part of the Galaxy there is a thickening called bulge. If we could look at our Galaxy from the side, we would see this thickening in its center, similar to two yolks in a frying pan, if they are folded with their lower bases - look at the picture.

There is a strong concentration of stars in the central part of the Galaxy. The length of the galactic bar is believed to be about 27,000 light years. This bar 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 primarily of red stars, which are considered very old. The jumper is surrounded by a ring. This ring contains most of the Galaxy's molecular hydrogen and is an active star-forming region in our Galaxy. If observed from the Andromeda Galaxy, the galactic bar 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 a bar in the inner part of the Galaxy, and in the inner part there are another pair of arms. These arms then transform into a four-arm structure observed in the neutral hydrogen line in the outer parts of the Galaxy.

Discovery of the Galaxy

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

Where in the Galaxy are we located?

Our Solar System is located closer to the edge of the Galaxy's 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 approximately 200 million years. Thus, during its entire existence, the Earth has flown around the center of the Galaxy no more than 30 times.
The spiral arms of the Galaxy rotate at a constant angular velocity, like spokes in a wheel, and the movement of stars occurs according to a different pattern, so almost all the stars in the disk either fall inside the spiral arms or fall out of them. 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.
For us earthlings, this is very important, since violent processes occur in the spiral arms, generating powerful radiation that is destructive to all living things. No atmosphere could protect against it. But our planet exists in a relatively calm place in the Galaxy and has not been affected by these cosmic cataclysms. That is why life was able to be born and survive on Earth - the Creator chose a calm place for our cradle of the Earth.
Our Galaxy is part of Local group of galaxies- a gravitationally bound group of galaxies, including the Milky Way galaxy, the Andromeda galaxy (M31) and the Triangulum galaxy (M33), you can see this group in the picture.

This is our Galaxy - the Milky Way. She is approximately 12 billion years old. The galaxy is a huge disk with giant spiral arms and a bulge in the center. There are countless such galaxies in space. - First of all, the Galaxy is a large cluster of stars. On average, it contains a hundred billion stars. This is a real stellar incubator - a place where stars are born and where they die. Stars in a galaxy appear in clouds of dust and gas, so-called nebulae.

Before us are the “Pillars of Creation” in the Eagle Nebula - a stellar incubator in the very heart of the Milky Way. Our Galaxy contains billions of stars, many of which are surrounded by planets or moons. For a long time, we knew very little about galaxies. A hundred years ago, humanity believed that the Milky Way was the only galaxy. Scientists called it “our island in the Universe.” Other galaxies did not exist for them. But in 1924, astronomer Edwin Hubble changed the general idea. Hubble observed space using the most advanced telescope of its time, with a lens diameter of 254 centimeters, located at Mount Wilson Observatory near Los Angeles. Deep in the night sky, he saw vague clouds of light that were very far from us. The scientist came to the conclusion that these are not individual stars, but entire star cities, galaxies far beyond the Milky Way. - Astronomers experienced a real space-time shock. In just a year, we have moved from the Universe inside the Milky Way to the Universe of billions of such galaxies. Hubble made one of the greatest discoveries in astronomy. There is not just one galaxy in space, but a great many galaxies. Our Galaxy has a vortex structure, has two spiral arms, and contains about 160 million stars. Galaxy M 87 is a giant ellipse. It is one of the oldest galaxies in the Universe, and the stars within it emit a golden light.

And this is the Sombrero Galaxy, in its center there is a huge luminous core, surrounded by a ring of gas and dust. Professor Michio (Michio) Kaku, physicist:- Galaxies are magnificent. In a sense, they represent the basic unit of the Universe. They are like giant lantern wheels that spin in space. These are real fireworks created by nature itself. Galaxies are huge - real giants. On Earth, distance is measured in kilometers; in space, astronomers use the unit of length “light year” - the distance traveled by light in a year. It is approximately equal to nine and a half trillion kilometers. Professor Lawrence Krauss, astrophysicist:- We are located 25 thousand light years from the center of our Galaxy, and its diameter is 100 thousand light years. But even with such impressive dimensions, it is only a small speck in the vast expanses of space. The Milky Way Galaxy seems huge to us. But compared to other galaxies in the Universe, it is quite small. Our closest galactic neighbor, the Andromeda Nebula, reaches a diameter of 200 thousand light years, 2 times the size of our Milky Way. M 87 is the largest elliptical galaxy in nearby space. It is much larger than Andromeda, but compared to the other giant M 87 it seems tiny. IC 10 11 is 6 million light years wide. This is the largest known galaxy. It is 60 times larger than the Milky Way. So we know that galaxies are huge, they are everywhere. But where did they come from? - One of the most important questions in astrophysics is the origin of galaxies. We still don't have an exact answer to this. The universe began with the Big Bang, which occurred approximately 13.7 billion years ago and was an incredibly hot, very dense phase. We know that nothing like galaxies could have existed at that time. Therefore, we can say that they appeared at the dawn of the Universe. To create stars, you need gravity. To unite stars into galaxies, even more is needed. The first stars appeared just 200 million years after the Big Bang. Then gravity pulled them together. This is how the first galaxies appeared. Professor Lawrence Krauss, astrophysicist:- The Hubble Space Telescope allowed us to look into the past, to get almost to the beginning of time, to the period when the first galaxies were just beginning to form. The Hubble Telescope sees many galaxies, but the light from most of them left its source thousands, millions, even billions of years ago. All this time he was flying towards us. Thus, today we are surveying galaxies that have already become history. Professor Lawrence Krauss, astrophysicist:- If you look deeper into space with the help of Hubble, you can see small specks that hardly resemble existing galaxies. These vague spots of light, clusters of millions, billions of stars that were just beginning to unite. These faint spots are the earliest of the galaxies. They formed about a billion years after the beginning of the Universe. Beyond this time, Hubble is powerless. If we need to explore deeper layers of the past, we need a different telescope. More than the one that can be launched into space. Now we have one in the high desert of Northern Chile. Its name is AST - Atacama Space Telescope. This highest of ground-based telescopes is located at 5190 meters above sea level. - I really like working at AST in extreme weather conditions. It can be very cold here and the winds blow fiercely. But a huge advantage for our work is that the sky is almost always clear. Clear skies are essential for the precise reflectors of AST, which focuses on early galaxies. Professor Suzanne Stags, physicist:- Using AST, we can zoom in on parts of the sky with incredible accuracy. We can also monitor the development of structures such as galaxies and galaxy clusters with extreme image clarity. ANT does not detect visible light, only cosmic microwaves left over from a time when the Universe was several hundred thousand years old. With this telescope you can not only see different galaxies, but also monitor their growth. Professor Suzanne Stags, physicist:- We are able to trace the processes of formation of galaxies and their clusters. We see traces of each of them, from several hundred thousand years from the beginning of the world to the present day. ANT has helped astronomers understand how galaxies have evolved almost since the beginning of time. Professor Michael Strauss, astrophysicist:- We began to answer questions: what galaxies looked like at the beginning of creation, whether they were similar to modern galaxies, how they grew and developed. Astronomers are observing how galaxies have traveled from small clusters of stars to today's network of star systems. Professor Lawrence Krauss, astrophysicist:- According to our current understanding, stars form clusters that unite into galaxies, which, in turn, form clusters of galaxies, and these form superclusters of galaxies - the largest units of space today. Early galaxies were shapeless clumps of stars, gas and dust. Today, the galaxies have taken on a neat, orderly appearance. How did chaotic clusters of stars turn into slender elliptical spiral systems? With the help of gravity. The force of gravity unites the stars and controls their future development. At the center of most galaxies there is an incredibly powerful destructive source of gravity. And our Milky Way is no exception. Galaxies have existed for more than 12 billion years. We know that these vast empires of stars take on a variety of forms, from vortex spirals to enormous balls of stars. Still, much in galaxies remains a mystery to us. Professor Michael Strauss, astrophysicist:- How did galaxies acquire their existing shape? Has a spiral galaxy always been shaped like a spiral? The answer is almost always no. Young galaxies are shapeless, chaotic collections of stars, gas and dust. Only after billions of years do they turn into such organized structures as, for example, a vortex galaxy or our Milky Way. Professor Lawrence Krauss, astrophysicist:- The Milky Way did not grow from one grain, from many. What is now called the Milky Way galaxy was once made up of many formations, shapeless structures that united into a single whole. Small structures converge due to the force of gravity. She gradually pulls the stars together. They spin faster and faster until they take the shape of a flat disk. The stars and gas then form giant spiral arms. This process has been repeated billions of times throughout space. Each galaxy is unique, but they all have one thing in common: they all revolve around their center. For years, scientists have wondered: what is powerful enough to change the behavior of the galaxy? And finally the answer was found. Black hole. And not just any black hole, but a supermassive black hole. - The first clue to the existence of supermassive black holes were galaxies, from the center of which a powerful column of energy burst out. It seemed to us that these black holes were feeding on nearby objects. Sort of like a giant Thanksgiving feast. Supermassive black holes feed on gas and stars. Sometimes the black hole eats them too greedily, and the food is thrown back into space as a beam of pure energy. This is called a quasar. When scientists see a quasar shooting out from the center of a galaxy, they know it has a supermassive black hole. What about our Galaxy? After all, she doesn’t have a quasar. Does this mean that it does not have a supermassive black hole? Andrea Ghez and her team have been trying to figure this out for 15 years. Professor Andrea Ghez, astronomer:- You can find out whether there is a supermassive black hole in the Milky Way by the movement of stars. Stars rotate, obeying the force of gravity, just like the planets around the Sun. However, stars located closer to the center of the Galaxy are hidden by clouds of dust. So Ghez used the giant Keck Telescope in Hawaii to see through the dust. A strange and cruel picture appeared before her eyes. Professor Andrea Ghez, astronomer:- In the center of our Galaxy, everything is taken to the extreme. Objects move at great speed, stars rush past one after another. Everything is bubbling, everything is seething. You will not see this anywhere in our Galaxy. Ghez and her team began taking pictures of some of the stars orbiting closer to the center of the Galaxy. Professor Andrea Ghez, astronomer:- We set ourselves the task of making a video with stars in the center of the Galaxy. I had to be patient and take picture after picture before the stars moved. Photographs of rotating stars have revealed something amazing. Their rotation speed was several million kilometers per hour. Professor Andrea Ghez, astronomer:- The most exciting moment in this experiment was when we received the second image and it became clear that the stars were rotating much faster than usual. This fully confirmed the hypothesis of a supermassive black hole.

The hypothesis was correct. Ghez and her team tracked the stars' trajectory and calculated their location from their center of rotation. There is only one thing powerful enough to spin huge stars around itself: a supermassive black hole. Professor Andrea Ghez, astronomer:- Only the gravitational force of a supermassive black hole causes stars to rotate. Their trajectories became evidence of a supermassive black hole at the center of our Galaxy. The black hole at the center of the Milky Way is gigantic. Its width is 24 million kilometers. Is there a danger to our planet? Professor Andrea Ghez, astronomer:- There is not the slightest danger that we will be sucked into a supermassive black hole. It's too far from us.

Planet Earth is located 25 thousand light years from the black hole at the center of the Milky Way. This is many billions of kilometers, so the Earth is safe. Bye. Supermassive black holes can be a source of powerful gravity. But they do not have enough strength to maintain the connection between the bodies of the galaxy. According to all the laws of physics, galaxies must decay. Why isn't this happening? There is a force in space greater than a supermassive black hole. It cannot be seen and is almost impossible to calculate. But it exists, it's called dark matter, and it's everywhere. Astronomers have discovered that at the center of galaxies there are supermassive black holes that attract stars at high speeds. But black holes are not strong enough to connect all the stars of a giant galaxy into a single whole. What kind of power is this? It remained a mystery until one independent scientist suggested that we were dealing with something unknown. In the 30s of the 20th century, Swiss astronomer Fritz Zwicky wondered why galaxies do not decay. According to his calculations, they do not generate enough gravitational force, therefore, they must scatter throughout space. “He stated: “I see with my own eyes that they do not fall apart, but stick together in a dense group. This means that something is preventing them from falling apart. But their own force of attraction is not powerful enough for this. Therefore, I conclude that there is something that is unknown to mankind, something unimaginable.” He gave it a name - dark matter. It was like a divine revelation. Professor Michio (Michio) Kaku, physicist:- Fritz Zwicky was several decades ahead of his time, and, of course, ran into misunderstandings among his fellow astronomers. But ultimately, he was right. If what Zwicky called dark matter united galaxies into groups, perhaps it also prevented individual galaxies from falling apart. To test this, scientists constructed virtual galaxies on a computer with virtual stars and virtual gravity. - We made a model of the galaxy, populated it with stars in orbits in the shape of a flat disk. Exactly like our Galaxy. And they decided that they had created the ideal galaxy. We wondered whether it would become a spiral or something else. But all our galaxies were falling apart. This galaxy did not have enough gravity to remain a single entity, so Ostriker added it along with virtual dark matter. Professor Jeremy Ostriker, astrophysicist:- Naturally, we wanted to try it, it solved the problem. Everything worked out. The gravitational force of dark matter turned out to be the binding force of the galaxy. Professor Jeremy Ostriker, astrophysicist:- Dark matter plays the role of the galaxy's scaffolding. With its help, galaxies are fixed in place and do not break up into separate bodies. Scientists now suggest that dark matter not only supports the galaxy, but gives impetus to its birth. Professor Michio (Michio) Kaku, physicist:- We believe that the first clusters of dark matter appeared as a result of the Big Bang. After some time, these clusters became obvious - grains from which galaxies grew. But scientists still don’t know what dark matter is. Professor Lawrence Krauss, astrophysicist:- Dark matter remains something inexplicable. We don't understand its essence. But it is definitely made of a different material... Professor Michio (Michio) Kaku, physicist:- ... than you and I. You cannot lean on it, you cannot touch it. Perhaps it is all around us, like a ghost that passes right through you, as if you do not exist at all. We may not know about dark matter, but the cosmos is filled with it. Dr Andrew Benson, astrophysicist:- The weight of dark matter is equivalent to at least six times the weight of the Universe from ordinary matter, that is, from which we are all made, without which it is impossible to imagine the normal operation of the laws of the Universe. However, these laws work. It turns out that dark matter really exists. And recently traces of it were discovered in deep space. Observations of its influence on the behavior of light helped make this statement. The beam path is bent. This phenomenon is called gravitational lensing.

Dr. Andrew Benson, astrophysicist: - The gravitational lens allows us to determine the presence of dark matter. How does it work? Imagine that a beam of light from some distant galaxy is flying towards us. If large accumulations of dark matter are encountered along its path, its trajectory will go around the dark matter under the influence of gravity. If you look at the depths of space through the Hubble telescope, the shape of some galaxies appears distorted and elongated.

This happens because dark matter distorts the image. She kind of puts it in a round aquarium. Dr Andrew Benson, astrophysicist:- By analyzing the outlines of these galaxies and the degree of distortion, it is possible to calculate with a certain accuracy the amount of dark matter in them. It has now become clear that dark matter is an integral part of the cosmos. It has existed since the beginning of time and influences everything, everywhere. It creates conditions for the birth of galaxies and prevents them from decaying. It is not visible to the naked eye, it is not calculated by instruments, but, nevertheless, dark matter is the mistress of the Universe. The galaxies seem to exist separately. There are indeed trillions of kilometers between them, but, nevertheless, the galaxies are united in groups, clusters of galaxies. Clusters of galaxies form superclusters, which include tens of thousands of galaxies. Where does our Milky Way rank among them? Professor Michio (Michio) Kaku, physicist:- A general plan of space shows that our Galaxy is part of a small group of about thirty galaxies. Our Milky Way and the Andromeda Nebula are the largest in it. But on a larger scale, we are just a small part of a supercluster of galaxies called Virgo. Currently, scientists are compiling a general map of the Universe and determining the locations of galaxy clusters and superclusters. This is the Apache Point Observatory in New Mexico, which is home to the Sloan Digital Sky Survey. It's just a small telescope, but it has a unique mission. Sloan's Digital Survey produces the first three-dimensional star map. It will allow us to determine the exact location of tens of millions of galaxies. To do this, the Sloan survey hunts for galaxies far beyond the Milky Way. It precisely determines the location of the galaxy, this information is recorded on aluminum disks. - These aluminum discs are about 30 inches wide and have 640 through holes, each of which is designed for the desired object in space. Space objects are galaxies. Light from the galaxy passes through the hole and further along the fiber optic cable. In this way, information about the distance and location of thousands of galaxies can be recorded and plotted on a three-dimensional map. Dan Long, engineer at Sloan Digital Sky Survey:- We determine their outlines, composition, and also how evenly they are scattered throughout outer space. All this is very important for astronomy, for understanding the laws of the Universe.

Here we see the fruits of their work: the largest three-dimensional map in existence today. The map shows things previously unseen: entire clusters and superclusters of galaxies. And the picture of the world continues to expand. We see that superclusters of galaxies form chains - filaments. The Sloan survey found one 1.4 billion light years across. It was called the Great Wall of Sloan. This is the largest single structure discovered in the history of science.

Dan Long, engineer at the Sloan Digital Sky Survey: “You feel the enormity of this space. Clusters, filaments, and each of these tiny lumps of light are huge galaxies. Not stars, but entire galaxies, and there are hundreds and thousands of them around. The Sloan Survey shows galactic geography on a large scale. Scientists went further. They built an entire Universe in a super-powerful computer. And here you cannot see individual galaxies; it is difficult to even make out their clusters. On the screen you can only see superclusters of galaxies that make up a giant cosmic web of filaments.

Professor Lawrence Krauss, astrophysicist: - If you look closely at the large-scale picture of space, you can discern a pattern of filaments, a cosmic web consisting of galaxies and their clusters that extend in thousands of different directions. From this point, space resembles in its structure a giant sponge. Each filament houses millions of galaxy clusters, all of them connected by dark matter. This computer model shows dark matter shining through tangles of filaments. Dr Andrew Benson, astrophysicist:- Dark matter affects the location of the galaxy in the Universe. Look at galaxies: they are not scattered randomly throughout space. They gather in small groups, which once again indicates the scale of the distribution of dark matter. Dark matter supports the entire macrostructure of space. It links galaxies into clusters, which in turn form superclusters. Superclusters are woven into chains of filaments. Without dark matter, the entire structure of the cosmos will simply fall apart. Here is our Universe close up.

Somewhere in the depths of this gigantic cosmic web, our Galaxy, the Milky Way, nestles in one of the filaments. It has existed for about 12 billion years, and it is about to die in a powerful cosmic collision. Galaxies are vast kingdoms of stars. Some are huge balls, others are complex spirals, but they are all constantly changing. Professor Lawrence Krauss, astrophysicist:- When we look at our Galaxy, it seems to us that it is unchanged and has existed forever. But that's not true. Our Galaxy is in constant motion, its nature has changed over cosmic time. Galaxies not only change, but also move. It happens that galaxies collide with each other, and then one absorbs the other. - In the Universe there is a whole flock of different galaxies that interact and collide with each other - with other members of the flock.

This is NGC 2207. At first glance, it looks like a huge double spiral galaxy, but in fact it is two galaxies colliding. The collision will last for millions of years, and eventually the two galaxies will merge into one. Similar collisions occur everywhere in space, and our Galaxy is no exception. Professor Lawrence Krauss, astrophysicist:- The Milky Way is essentially a cannibal. It acquired its present form by absorbing many smaller galaxies. Even today, small stripes of stars of the former individual galaxies that remained without boundaries, which replenished the Milky Way, are visible on its body. But these are “little flowers” ​​compared to what awaits us in the future. We are rapidly moving towards the Andromeda galaxy, and this does not bode well for the Milky Way. Professor Michio (Michio) Kaku, physicist:- The Milky Way is approaching Andromeda at a speed of approximately 250 thousand miles per hour, which means that in 5-6 billion years our Galaxy will no longer exist. Dr TJ Cox, astrophysicist:- Andromeda is approaching us with all its monstrous mass. When galaxies interact, each of them individually disintegrates, and their bodies gradually mix and grow like a snowball. Professor Michio (Michio) Kaku, physicist:- Two galaxies begin the dance of death.

This is a reproduction of a future collision, accelerated millions of times. When two galaxies collide, clouds of gas and dust fly off in all directions. The gravitational force of merging galaxies tears stars from their orbits and throws them into the dark depths of the Universe. Professor Michio (Michio) Kaku, physicist:- The Judgment Day of the Milky Way will be a picturesque picture, and we will watch the destruction of our Galaxy from the front rows. Gradually, the two galaxies will pass right through each other, and then return to merge into a single whole. Oddly enough, the stars will not collide with each other. They are still too far apart. Dr TJ Cox, astrophysicist:- The stars will just mix. The probability of two separate stars colliding is virtually zero. However, the dust and gas between the stars will begin to heat up. At some point they will ignite, and the colliding galaxies will become white hot. Professor Michio (Michio) Kaku, physicist:- At some point, a real fire may break out in the skies. Dr TJ Cox, astrophysicist:- The Milky Way and Andromeda galaxies will cease to exist. A new galaxy will appear - Melkomeda, which will become a new cosmic unit. The new Melkomed galaxy will look like a huge ellipse without arms or spirals. We will not be able to escape the future. The question is what it will bring to planet Earth. Professor Michio (Michio) Kaku, physicist:- We can either be thrown into outer space along with fragments of the arms of the Milky Way, or sucked into the body of a new galaxy. Stars and planets will be scattered throughout the galaxy and beyond, and for planet Earth this could be a sad end. The Universe will see a collision of galaxies more than once. But the era of galactic cannibalism will also end someday. Galaxies are home to stars, solar systems, planets and moons. The galaxy provides itself with everything it needs. Professor Lawrence Krauss, astrophysicist:- Galaxies are the living blood in the body of the Universe. We exist because we originated within the Galaxy, and everything we see, everything that matters to us, happens within the Galaxy. With all this, galaxies are fragile structures held together by dark matter. Scientists have discovered another active force in the Universe. It is called dark energy. Dark energy acts in opposition to dark matter. If one connects galaxies, then the other separates them from each other. Professor Lawrence Krauss, astrophysicist:- Dark energy, which we have known about for literally one decade, is the dominant feature of the cosmos and represents an even greater mystery. We don't have the slightest idea why it is needed. Dr Andrew Benson, astrophysicist:- It's hard to say what it consists of. We know that it exists, but what it is and what its function remains a mystery. Professor Jeremy Ostriker, astrophysicist:- Dark energy is a strange thing. It seems that outer space is riddled with tiny sources that cause objects to repel each other. Scientists believe that in the distant, distant future, dark energy will win the cosmic battle with dark matter, and galaxies will begin to disintegrate. Professor Lawrence Krauss, astrophysicist:- Dark energy will destroy galaxies. This will happen when other galaxies begin to gradually move away from ours until they disappear from view. And since the galaxies will fly apart at speeds faster than the speed of light, they will literally disappear from our eyes. Not today, not tomorrow, but perhaps in trillions of years we will remain in an empty Universe. Galaxies will become lonely islands in the vast expanses of space. But this will not happen very soon. Today the Universe is thriving, and galaxies create all the conditions for the existence of life. Professor Michio (Michio) Kaku, physicist:- Without galaxies, I wouldn’t be here, you wouldn’t be here, and life might not have arisen at all. We are incredibly lucky: life originated on Earth only due to the fact that our tiny Solar system is located in the right part of the Galaxy. If we had positioned ourselves a little closer to the center, we would not have survived. Professor Michio (Michio) Kaku, physicist:- Life in the center of the Galaxy is very cruel, and if our solar system was located closer to the center, there would be so much radiation that we would not be able to survive. Living too far from the center is also no better. The number of stars at the edges of the Galaxy decreases sharply. We might not exist at all. Professor Michio (Michio) Kaku, physicist:- We can say that we have chosen the golden mean of the Galaxy: not far, not close, but right in the bull’s eye. Scientists believe that this golden belt of the Galaxy may contain millions of stars, and among them there are likely to be other solar systems capable of supporting life. And they are in our own Galaxy. And if we have a habitable zone, it can also exist in other galaxies. Professor Andrea Ghez, astronomer:- The Universe is huge, it presents us with surprises again and again. Professor Jeremy Ostriker, astrophysicist:- Every time we think we have found the answer to a question, it turns out that it has led us to an even bigger question. This sparks interest. Our native Milky Way Galaxy and other galaxies in the Universe pose before us endless questions that require answers, and secrets that have not yet been discovered by anyone. Professor Michio (Michio) Kaku, physicist:- Who would have imagined 10 years ago that we would be able to find a black hole in the center of the Galaxy? Which astronomer would have believed in dark matter and dark energy just 10 years ago? More and more scientists are devoting their research to galaxies. It is in them that the key to understanding the laws of the Universe lies. Professor Lawrence Krauss, astrophysicist:“Isn’t it amazing to live at this point in the history of space on this small planet on the outskirts of a random galaxy and receive answers to questions about the Universe from its very beginning to its very end?” We should endlessly rejoice at this brief moment in the rays of the Sun. Galaxies are born, develop, collide and die. Galaxies are superstars for the world of science. Every astronomer has his favorites. Professor Michael Strauss, astrophysicist:- Vortex galaxy or M51. Professor Jeremy Ostriker, astrophysicist:- If I could hang it on the wall, I would choose the Sombrero Galaxy. Professor Lawrence Krauss, astrophysicist:- The Sombrero Galaxy, ring galaxies - they are very beautiful. Professor Michio (Michio) Kaku, physicist:- My favorite galaxy is the Milky Way. This is my home. We are lucky that the Milky Way provides us with everything we need to live. Our fate directly depends on our Galaxy and on all other galaxies. They created us, they gave shape to our lives, and our future is in their hands.

The Universe is huge, it stretches over tens of billions of light years, and almost all of this space is empty. But it also contains countless giant star islands - galaxies with billions of stars. One of these galaxies is the Milky Way, where we live, and it is quite large. But what is the largest galaxy in the Universe known to scientists?

There are several such record holders, and they all amaze the imagination. Our Milky Way, which itself is huge, larger than many other galaxies, contains 200-400 billion stars, but in front of these monsters it is just a dwarf.

This magnificent spiral galaxy is located in the constellation Andromeda, and is turned flat towards us. The distance to it is 200 million light years, and in the sky it looks like a faint star with a brightness of 13.1m, that is, it can only be seen through a fairly powerful telescope with a large aperture.

What's so special about NGC 262? Because it is one of the largest galaxies. The gas surrounding it alone reaches 50 billion solar masses—that’s exactly how many stars like the Sun could form from it.

The galaxy itself contains about 15 trillion stars. Even if we take the maximum number of stars in our rather large Milky Way at 400 billion, NGC 242 contains 6 times more of them!

The size of this giant galaxy is 1,300,000 light years, which is 13 times larger than the diameter of our home galaxy! It's just a huge galaxy, a giant among giants.

Hercules-A – number 2

The Hercules-A galaxy is located in the constellation Hercules. It is 10 times further away than NGC 262 - the light from this galaxy takes 2 billion years to reach us.

The diameter of this monster is 1,500,000 light years, which is larger than the size of the previous candidate, and 15 times larger than the size of our galaxy. The mass of Hercules-A is 2000 times heavier than our Milky Way. The black hole at the center of this galaxy alone has a mass of 2.5 billion solar masses!

IC 1101 is the largest galaxy in the Universe

This galaxy was discovered by William Herschel in 1790. It is located in the constellation Virgo, in a large cluster of galaxies, at a distance of just over 1 billion light years from us. It is classified as an elliptical and has a brightness of 10.1m in the sky.

IC 1101 is the largest galaxy in the Universe.

IC 1101 is a real monster. This is the largest galaxy in the Universe, at least in the visible part. Even previous candidates pale in comparison to her. It is 2000 times heavier than our Milky Way, and 60 times larger! A ray of light will take 6 million years to cross it from edge to edge. That is, this galaxy is even 4 times larger than the previous galaxy Hercules-A. There are 100 trillion stars in it!

This giant galaxy was formed as a result of the merger of other, smaller ones. Now it is so huge and massive that it is absorbing other galaxies located nearby, and therefore everything is growing.

Many facts known today seem so familiar and familiar that it is difficult to imagine how we lived without them before. However, scientific truths for the most part did not appear at the dawn of mankind. Almost everything concerns knowledge about outer space. The types of nebulae, galaxies, and stars are known to almost everyone today. Meanwhile, the path to a modern understanding of the structure of the Universe was quite long. It took a long time for people to realize that the planet is part of the Solar System, and it is part of the Galaxy. Types of galaxies began to be studied in astronomy even later, when it was understood that the Milky Way is not alone and the Universe is not limited to it. The founder of systematization, as well as the general knowledge of space outside the “milk road,” was Edwin Hubble. Thanks to his research, today we know a lot about galaxies.

Hubble studied nebulae and determined that many of them were formations similar to the Milky Way. Based on the collected material, he described what the galaxy looks like and what types of similar space objects exist. Hubble measured the distances to some of them and proposed his own systematization. Scientists still use it today.

He divided all the many systems in the Universe into 3 types: elliptical, spiral and irregular galaxies. Each type is intensively studied by astrologers around the world.

The piece of the Universe where the Earth is located, the Milky Way, belongs to the “spiral galaxy” type. Types of galaxies are identified based on differences in their shapes, which affect certain properties of the objects.

Spiral

The types of galaxies are not equally distributed throughout the Universe. According to modern data, spiral-shaped ones are more common than others. In addition to the Milky Way, this type includes the Andromeda Nebula (M31) and the galaxy in the constellation Triangulum (M33). Such objects have an easily recognizable structure. If you look from the side at what such a galaxy looks like, the view from above will resemble concentric circles spreading across the water. Spiral arms radiate from a spherical central bulge called the bulge. The number of such branches varies - from 2 to 10. The entire disk with spiral arms is located inside a rarefied cloud of stars, which in astronomy is called a “halo”. The core of the galaxy is a cluster of stars.

Subtypes

In astronomy, the letter S is used to designate spiral galaxies. They are divided into types depending on the structural design of the arms and features of the general shape:

Galaxy Sa: the arms are tightly twisted, smooth and unshaped, the bulge is bright and extended;

galaxy Sb: the arms are powerful, clear, the bulge is less pronounced;

galaxy Sc: the arms are well developed, have a ragged structure, the bulge is poorly visible.

In addition, some spiral systems have a central, almost straight bridge (called a “bar”). In this case, the letter B (Sba or Sbc) is added to the designation of the galaxy.

Formation

The formation of spiral galaxies appears to be similar to the appearance of waves from the impact of a stone on the surface of water. According to scientists, a certain impetus led to the appearance of the sleeves. The spiral branches themselves represent waves of increased density of matter. The nature of the push can be different, one of the options is movement in the central mass of stars.

The spiral arms are young stars and neutral gas (the main element is hydrogen). They lie in the plane of rotation of the galaxy, so it resembles a flattened disk. The formation of young stars may also be at the center of such systems.

Nearest neighbor

The Andromeda Nebula is a spiral galaxy: a view from above reveals several arms emanating from a common center. From Earth, it can be seen with the naked eye as a blurry, foggy spot. Our galaxy's neighbor is slightly larger in size: 130 thousand light years across.

Although the Andromeda nebula is the closest galaxy to the Milky Way, the distance to it is enormous. It takes light two million years to travel through it. This fact perfectly explains why flights to a neighboring galaxy are still only possible in science fiction books and films.

Elliptic systems

Let us now consider other types of galaxies. A photo of the elliptical system clearly shows its difference from its spiral counterpart. Such a galaxy has no arms. It looks like an ellipse. Such systems can be compressed to varying degrees, and can be something like a lens or a sphere. There is practically no cold gas found in such galaxies. The most impressive representatives of this type are filled with rarefied hot gas, the temperature of which reaches a million degrees or more.

A distinctive feature of many elliptical galaxies is their reddish tint. For a long time, astrologers believed this to be a sign of the antiquity of such systems. It was believed that they consisted mainly of old stars. However, research in recent decades has shown the fallacy of this assumption.

Education

For a long time, there was another guess related to elliptical galaxies. They were considered the very first to appear, formed shortly after the Great Explosion. Today this theory is considered outdated. German astrologers Alar and Yuri Thumre, as well as the South American scientist Francois Schweizer, made a great contribution to its refutation. Their research and discoveries in recent years confirm the truth of another guess, the hierarchical model of development. According to it, larger structures were formed from rather small ones, that is, galaxies did not form immediately. Their appearance was preceded by the formation of star clusters.

According to modern concepts, elliptical systems were formed from spiral-shaped arms as a result of the merger. One confirmation of this is the huge number of “twisted” galaxies observed in remote areas of space. On the contrary, in the closest regions there is a noticeably higher concentration of elliptical systems, quite bright and extended.

Symbols

Elliptical galaxies also received their own designations in astronomy. For them, the symbol “E” and numbers from 0 to 6 are used, which indicate the degree of flattening of the system. E0 are galaxies with an almost regular spherical shape, and E6 are the flattest.

Raging Cannonballs

Elliptical galaxies include the systems NGC 5128 from the constellation Centaur and M87, located in Virgo. Their feature is powerful radio emission. Astrologers are first interested in the structure of the central part of such galaxies. Observations by Russian scientists and studies by the Hubble telescope show quite high activity in this zone. In 1999, South American astrologers obtained data on the core of the elliptical galaxy NGC 5128 (constellation Centaur). There, in constant motion, there are huge masses of hot gas, swirling around the center of, perhaps, a black hole. There is no exact data on the nature of such processes yet.

Irregularly shaped systems

The appearance of a third type galaxy is not structured. Such systems are ragged objects of chaotic shape. Irregular galaxies are found in the vastness of space less often than others, but their study contributes to a more accurate understanding of the processes occurring in the Universe. Up to 50% of the mass of such systems is gas. In astronomy, it is customary to designate such galaxies using the symbol Ir.

Satellites

Irregular galaxies include the two systems closest to the Milky Way. These are its satellites: the Large and Small Magellanic Clouds. They are clearly visible in the night sky of the southern hemisphere. The largest of the galaxies is located at a distance of 200 thousand light years from us, and the smaller one is separated from the Milky Way by 170,000 light years. years.

Astrologers are closely studying the vastness of these systems. And the Magellanic Clouds repay this in full: very noteworthy objects are often discovered in satellite galaxies. For example, on February 23, 1987, a supernova exploded in the Large Magellanic Cloud. The Tarantula emission nebula is also of particular interest.

It is also located in the Large Magellanic Cloud. Here scientists discovered a region of constant star formation. Some of the stars that make up the nebula are only two million years old. In addition, the most impressive star discovered in 2011, RMC 136a1, is located right there. Its mass is 256 solar.

Interaction

The main types of galaxies describe the features of the shape and arrangement of the elements of these cosmic systems. However, the question of their assistance is no less fascinating. It's no secret that all space objects are in constant motion. Galaxies are no exception. Types of galaxies, at least some of their representatives, could have been formed in the process of merger or collision of two systems.

If we remember what such objects are, it becomes clear how large-scale changes occur during their interaction. During a collision, a colossal amount of energy is released. It is curious that such events are even more possible in the vastness of space than the meeting of two stars.

However, the “communication” of galaxies does not always end with a collision and explosion. A small system can pass through its large brother, disturbing its structure. This is how formations are formed that are similar in appearance to elongated corridors. They consist of stars and gas and often become zones for the formation of new luminaries. Examples of such systems are well known to scientists. One of them is the Cartwheel galaxy in the constellation Sculptor.

In some cases, the systems do not collide, but pass by each other or only slightly touch. However, regardless of the degree of interaction, it leads to serious changes in the structure of both galaxies.

Future

According to scientists' assumptions, it is possible that after some fairly long time the Milky Way will absorb its closest satellite, a relatively recently discovered system, tiny by cosmic standards, located at a distance of 50 light years from us. Research data indicate an impressive lifespan for this satellite, which may end in the process of merging with its larger neighbor.

Collision is a likely future for the Milky Way and the Andromeda Galaxy. Now the huge neighbor is separated from us by about 2.9 million light years. Two galaxies are approaching each other at a speed of 300 km/s. A possible collision, according to scientists, will occur in three billion years. However, today no one knows for sure whether it will happen or whether the galaxies will only slightly touch each other. For forecasting, there is not enough data on the characteristics of the movement of both objects.

Modern astronomy studies in detail such cosmic structures as galaxies: types of galaxies, features of interaction, their differences and similarities, the future. There is still a lot that is unclear in this area and requires additional research. The types of structure of galaxies are known, but there is no precise understanding of many details associated, for example, with their formation. The current pace of improvement of knowledge and technology, however, allows us to hope for significant breakthroughs in the future. In any case, galaxies will not cease to be the center of many research projects. And this is connected not only with the curiosity inherent in all people. Data on cosmic patterns and the life of stellar systems make it possible to predict the future of our piece of the Universe, the Milky Way galaxy.

Those who have a little idea about the Universe are well aware that the cosmos is constantly in motion. The universe is expanding every second, becoming larger and larger. Another thing is that on the scale of human perception of the world, it is quite difficult to understand the size of what is happening and imagine the structure of the Universe. In addition to our galaxy, in which the Sun is located and we are located, there are dozens, hundreds of other galaxies. No one knows the exact number of distant worlds. How many galaxies are in the Universe can only be known approximately by creating a mathematical model of the cosmos.

Therefore, given the size of the Universe, we can easily assume that tens, hundreds of billions of light years from Earth, there are worlds similar to ours.

Space and worlds that surround us

Our galaxy, which received the beautiful name “Milky Way,” was, according to many scientists, the center of the universe just a few centuries ago. In fact, it turned out that this is only part of the Universe, and there are other galaxies of various types and sizes, large and small, some further, others closer.

In space, all objects are closely interconnected, move in a certain order and occupy an allotted place. The planets we know, the stars we know, black holes, and our solar system itself are located in the Milky Way galaxy. The name is not accidental. Even ancient astronomers, observing the night sky, compared the space around us to a milk track, where thousands of stars look like drops of milk. The Milky Way Galaxy, the celestial galactic objects in our field of vision, make up the nearby cosmos. What may be beyond the visibility of telescopes became known only in the 20th century.

Subsequent discoveries, which expanded our cosmos to the size of the Metagalaxy, led scientists to the theory of the Big Bang. A grandiose cataclysm occurred almost 15 billion years ago and served as an impetus for the beginning of the processes of formation of the Universe. One stage of the substance was replaced by another. From dense clouds of hydrogen and helium, the first beginnings of the Universe began to form - protogalaxies consisting of stars. All this happened in the distant past. The light of many celestial bodies, which we can observe in the strongest telescopes, is only a farewell greeting. Millions of stars, if not billions, that dotted our sky are located a billion light years from Earth, and have long ceased to exist.

Map of the Universe: nearest and farthest neighbors

Our Solar System and other cosmic bodies observed from Earth are relatively young structural formations and our closest neighbors in the vast Universe. For a long time, scientists believed that the dwarf galaxy closest to the Milky Way was the Large Magellanic Cloud, located only 50 kiloparsecs. Only very recently have the real neighbors of our galaxy become known. In the constellation Sagittarius and in the constellation Canis Major there are small dwarf galaxies whose mass is 200-300 times less than the mass of the Milky Way, and the distance to them is just over 30-40 thousand light years.

These are one of the smallest universal objects. In such galaxies the number of stars is relatively small (on the order of several billion). As a rule, dwarf galaxies gradually merge or are absorbed by larger formations. The speed of the expanding Universe, which is 20-25 km/s, will unwittingly lead neighboring galaxies to a collision. When this will happen and how it will turn out, we can only guess. The collision of galaxies is happening all this time, and due to the transience of our existence, it is not possible to observe what is happening.

Andromeda, two to three times the size of our galaxy, is one of the closest galaxies to us. It continues to be one of the most popular among astronomers and astrophysicists and is located just 2.52 million light years from Earth. Like our galaxy, Andromeda is a member of the Local Group of galaxies. The size of this giant cosmic stadium is three million light years across, and the number of galaxies present in it is about 500. However, even such a giant as Andromeda looks short in comparison with the galaxy IC 1101.

This largest spiral galaxy in the Universe is located more than a hundred million light years away and has a diameter of more than 6 million light years. Despite containing 100 trillion stars, the galaxy is primarily composed of dark matter.

Astrophysical parameters and types of galaxies

The first space explorations carried out at the beginning of the 20th century provided plenty of food for thought. The cosmic nebulae discovered through the lens of a telescope, of which more than a thousand were eventually counted, were the most interesting objects in the Universe. For a long time, these bright spots in the night sky were considered to be gas accumulations that were part of the structure of our galaxy. Edwin Hubble in 1924 managed to measure the distance to a cluster of stars and nebulae and made a sensational discovery: these nebulae are nothing more than distant spiral galaxies, independently wandering across the scale of the Universe.

An American astronomer was the first to suggest that our Universe is made up of many galaxies. Space exploration in the last quarter of the 20th century, observations made using spacecraft and technology, including the famous Hubble telescope, confirmed these assumptions. Space is limitless and our Milky Way is far from the largest galaxy in the Universe and, moreover, is not its center.

Only with the advent of powerful technical means of observation, the Universe began to take on clear outlines. Scientists are faced with the fact that even such huge formations as galaxies can differ in their structure and structure, shape and size.

Through the efforts of Edwin Hubble, the world received a systematic classification of galaxies, dividing them into three types:

• spiral;
• elliptical;
• incorrect.

Elliptical and spiral galaxies are the most common types. These include our Milky Way galaxy, as well as our neighboring Andromeda galaxy and many other galaxies in the Universe.

Elliptical galaxies have the shape of an ellipse and are elongated in one direction. These objects lack sleeves and often change their shape. These objects also differ from each other in size. Unlike spiral galaxies, these cosmic monsters do not have a clearly defined center. There is no core in such structures.

According to the classification, such galaxies are designated by the Latin letter E. All currently known elliptical galaxies are divided into subgroups E0-E7. The distribution into subgroups is carried out depending on the configuration: from almost circular galaxies (E0, E1 and E2) to highly elongated objects with indices E6 and E7. Among the elliptical galaxies there are dwarfs and true giants with diameters of millions of light years.

There are two subtypes of spiral galaxies:

• galaxies presented in the form of a crossed spiral;
• normal spirals.

The first subtype is distinguished by the following features. In shape, such galaxies resemble a regular spiral, but in the center of such a spiral galaxy there is a bridge (bar), giving rise to arms. Such bridges in a galaxy are usually the result of physical centrifugal processes that divide the galactic core into two parts. There are galaxies with two nuclei, the tandem of which makes up the central disk. When the nuclei meet, the bridge disappears and the galaxy becomes normal, with one center. There is also a bridge in our Milky Way galaxy, in one of the arms of which our Solar system is located. From the Sun to the center of the galaxy, the path, according to modern estimates, is 27 thousand light years. The thickness of the Orion Cygnus arm, in which our Sun and our planet reside, is 700 thousand light years.

In accordance with the classification, spiral galaxies are designated by the Latin letters Sb. Depending on the subgroup, there are other designations for spiral galaxies: Dba, Sba and Sbc. The difference between the subgroups is determined by the length of the bar, its shape and the configuration of the sleeves.

Spiral galaxies can range in size from 20,000 light-years to 100,000 light-years in diameter. Our Milky Way galaxy is in the “golden mean”, its size gravitating toward medium-sized galaxies.

The rarest type is irregular galaxies. These universal objects are large clusters of stars and nebulae that do not have a clear shape or structure. In accordance with the classification, they received the indices Im and IO. As a rule, structures of the first type do not have a disk or it is weakly expressed. Often such galaxies can be seen to have similar arms. Galaxies with IO indices are a chaotic collection of stars, clouds of gas and dark matter. Prominent representatives of this group of galaxies are the Large and Small Magellanic Clouds.

All galaxies: regular and irregular, elliptical and spiral, consist of trillions of stars. The space between stars and their planetary systems is filled with dark matter or clouds of cosmic gas and dust particles. In the spaces between these voids there are black holes, large and small, which disturb the idyll of cosmic tranquility.

Based on the existing classification and research results, we can answer with some confidence the question of how many galaxies there are in the Universe and what type they are. There are more spiral galaxies in the Universe. They constitute more than 55% of the total number of all universal objects. There are half as many elliptical galaxies - only 22% of the total number. There are only 5% of irregular galaxies similar to the Large and Small Magellanic Clouds in the Universe. Some galaxies are neighboring us and are in the field of view of the most powerful telescopes. Others are in the farthest space, where dark matter predominates and the blackness of endless space is more visible in the lens.

Galaxies up close

All galaxies belong to certain groups, which in modern science are usually called clusters. The Milky Way is part of one of these clusters, which contains up to 40 more or less known galaxies. The cluster itself is part of a supercluster, a larger group of galaxies. The Earth, along with the Sun and the Milky Way, is part of the Virgo supercluster. This is our actual cosmic address. Together with our galaxy, there are more than two thousand other galaxies in the Virgo cluster, elliptical, spiral and irregular.

The map of the Universe, which astronomers rely on today, gives an idea of ​​what the Universe looks like, what its shape and structure are. All clusters gather around voids or bubbles of dark matter. It is possible that dark matter and bubbles are also filled with some objects. Perhaps this is antimatter, which, contrary to the laws of physics, forms similar structures in a different coordinate system.

Current and future state of galaxies

Scientists believe that it is impossible to create a general portrait of the Universe. We have visual and mathematical data about the cosmos that is within our understanding. The real scale of the Universe is impossible to imagine. What we see through a telescope is starlight that has been coming to us for billions of years. Perhaps the real picture today is completely different. As a result of cosmic cataclysms, the most beautiful galaxies in the Universe could already turn into empty and ugly clouds of cosmic dust and dark matter.

It cannot be ruled out that in the distant future, our galaxy will collide with a larger neighbor in the Universe or swallow a dwarf galaxy existing next door. What will be the consequences of such universal changes remains to be seen. Despite the fact that the convergence of galaxies occurs at the speed of light, earthlings are unlikely to witness a universal catastrophe. Mathematicians have calculated that just over three billion Earth years are left before the fatal collision. Whether life will exist on our planet at that time is a question.

Other forces can also interfere with the existence of stars, clusters and galaxies. Black holes, which are still known to man, are capable of swallowing a star. Where is the guarantee that such monsters of enormous size, hiding in dark matter and in the voids of space, will not be able to swallow the galaxy entirely?