Everyone has ever thought about how big and unknown the world around us is. Being part of an immeasurably vast Universe, we often ask ourselves questions with curiosity: “How big is the Universe?”, “What does it consist of?”, “Is there intelligent life besides us?”, “How many galaxies are there in the Universe?” and many others.

This article seeks to answer some of them and expand general knowledge and understanding of the universe and its constituent parts and systems.

Universe

The universe includes everything that exists. From cosmic dust to giant stars; from the smallest hydrogen atoms to subjective ideas and abstract concepts. Everything that is located and functions in space is part of the Universe.

It is studied by various sciences. Physics, astronomy and cosmology are pioneers in the study of the Universe in objective reality. It is they who are trying to answer the question of what the cosmos consists of or how many galaxies there are in the Universe. Philosophy has been studying the Universe in subjective reality since its first days. The mother of all sciences is not concerned with how many galaxies there are in the Universe, but with how she and her perception affect our life and development.

Given the incredible size of the universe and the mass of bodies and substances found in it, it is not surprising that we have accumulated a huge amount of knowledge; it is also not surprising that many more questions remain unanswered. Only a small part of the Universe at a certain point in time lends itself to physical study, we can only guess about the rest. The past and future of the Universe are only assumptions and predictions, and only a tiny fraction of its present is revealed to us.

What do we really know about her?

We are absolutely sure that the Universe is huge, and with a high degree of probability we can say that it is immeasurable. To measure the distances between space objects, a completely “universal” unit is used - a light year. This is the distance that a beam of light can cover in a year.

The matter that makes up the Universe surrounds our planet at a distance of at least 93 billion light years. For comparison, our galaxy occupies a place that can be overcome for 100,000 light years.

Scientists divide the cosmic matter into a cluster of atoms - an understandable and studied physical matter, which is also called baryonic matter. However, most of the Universe is occupied by unexplored dark energy, the properties of which are unknown to scientists. Also, a large part of the visible space of the Universe is occupied by a dark or hidden mass, which scientists call invisible matter.

The accumulation of baryonic matter forms stars, planets and other cosmic bodies, which, in turn, form galaxies. The latter are in motion and move away from each other. It is impossible to answer the question of how many galaxies are in the Universe with accuracy.

What can we only guess?

The past of the Universe and the process of its formation are not exactly known. Scientists suggest that the universe is almost 14 billion years old, and was formed after the expansion of concentrated hot matter, which in cosmology is called the Big Bang Theory.

Everything on which the main theoretical models of the evolution of the Universe are based, scientists obtain by observing the part of it visible to us. It is impossible to prove how true any of the currently existing models is. Most scientists agree with the theory of the expansion of the universe - after the "big bang" cosmic matter continues its movement from its center.

It is worth remembering that all these models are theoretical, and it is impossible to test them in practice due to many reasons. Therefore, it is worth concentrating on accessible and proven knowledge that answers questions about how many stars are in the galaxy, and how many galaxies are in the Universe. A photo taken with modern technology called Hubble (from Hubble Ultra Deep Field) allows you to see the location of many galaxies in a small visible part of the sky.

What is a galaxy?

A galaxy is a collection of stars, gas, dust, and hidden mass. The gravitational interaction of baryonic matter and dark cosmic mass unites the galaxy into a tightly connected group of cosmic bodies. Galaxies move at a certain speed, which confirms the theory of the expansion of the Universe, but the gravitational center of the galaxy does not allow the movement of the Universe to influence its formation. All bodies in the galaxy revolve around a gravitational center.

Galaxies can be of various types, sizes and consist of many systems. There is no single answer to the question of how many galaxies there are in the universe, since the possibility of the existence of two identical galaxies is unlikely. By type, they are divided into:

• elliptical;
• spiral;
• lenticular;
• with jumper;
• wrong.

Galaxies are classified according to their size as dwarf, medium, large, and giant. There is no definite answer to the question of how many systems there are in a galaxy, since the number of systems and star clusters depends on many different factors, such as the gravitational field of stars, the size of the galaxy, and many others.

Scales of galaxies

Each galaxy is made up of star systems, clusters, and interstellar clouds. Several neighboring galaxies can be attracted to each other and form a local group. It can contain from three to 30 galaxies of various types and sizes.

Clusters of local groups, in turn, form huge stellar clouds, which are called superclusters of galaxies. The gravitational interdependence of galaxies with respect to neighbors from the local group, as well as from the supercluster, is based on the interaction of atoms of baryonic matter with hidden matter.

Milky Way

Our home galaxy, the Milky Way, is a barred disk-shaped spiral. The core of the galaxy is made up of old stars - red giants. The Milky Way shares the Local Group with two neighboring galaxies: the Andromeda Nebula and the Triangulum Galaxy. The supercluster to which they belong is called the Virgo Supercluster.

In the local group of the Milky Way, in addition to three large galaxies, there are about 40 dwarf satellite galaxies, which are attracted by the stronger gravitational fields of their large neighbors. There may be as many black holes and spaces of dark matter in the Virgo supercluster as there are galaxies. The exact number of stars in the Milky Way is unknown, but the most rough estimate is 200 billion. The diameter of the Milky Way is one hundred thousand light years, and the average thickness of the disk is one thousand light years.

The youngest stars and their clusters are closer to the surface of the disk, while the center of the galaxy's core, according to scientists, is a huge black hole, around which there is a very high concentration of stars. The main star of our system - the Sun - is located closer to the surface of the disk.

solar system

The solar system is 4.5 billion years old and is in the shape of a disk. The heaviest element of the system is its center - the Sun, it accounts for almost the entire mass, which causes a strong gravitational attraction. The eight planets orbiting it make up only 0.14% of the system's total mass. Earth belongs to the four small terrestrial planets, along with Mars, Venus and Mercury. The rest of the planets are called gas giants because they are composed mostly of gases.

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


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

What does the word "galaxy" mean?

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

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

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

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

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

What is a galaxy made of?

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

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

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

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

What is at the center of the galaxy?

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


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

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

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

Which is bigger, the universe or the galaxy?

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

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

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


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

Many of the facts known today seem so familiar and familiar that it is hard to imagine how people used to live without them. However, most scientific truths did not originate at the dawn of mankind. In many ways, this concerns knowledge about outer space. Types of nebulae, galaxies, stars are known to almost everyone today. Meanwhile, the path to modern understanding was quite long. People did not immediately realize that the planet is part of the solar system, and it is part of the galaxy. The types of galaxies began to be studied in astronomy even later, when the understanding came that the Milky Way is not alone and the Universe is not limited to it. as well as in general the knowledge of space outside the "milk road", was Edwin Hubble. Thanks to his research, today we know a lot about galaxies.

Types of galaxies in the universe

Hubble studied nebulae and proved that many of them are formations similar to the Milky Way. Based on the collected material, he described what kind of galaxy has and what types of similar space objects exist. Hubble measured the distances to some of them and proposed his own classification. Scientists still use it today.

He divided the entire set of systems in the Universe into 3 types: elliptical, spiral and irregular galaxies. Each type is actively studied by astronomers around the world.

The piece of the Universe where the Earth is located, the Milky Way, belongs to the type of "spiral galaxies". Types of galaxies are distinguished on the basis of differences in their shapes that affect certain properties of objects.

Spiral

The types of galaxies are not equally distributed throughout the universe. According to modern data, spiral ones are more common than others. In addition to the Milky Way, this type includes the Andromeda Nebula (M31) and the galaxy in (M33). Such objects have an easily recognizable structure. If you look from the side, what such a galaxy looks like, the view from above will resemble concentric circles diverging through 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 is called a "halo" in astronomy. The core of a galaxy is a collection 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 the features of the general shape:

galaxy Sa: tightly curled, smooth and unshaped arms, bright and extended bulge;

galaxy Sb: strong, distinct arms, less pronounced bulge;

galaxy Sc: the arms are well developed, they are 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 galaxy designation.

Formation

The formation of spiral galaxies seems to be similar to the appearance of waves from the impact of a stone on the surface of the water. According to scientists, a certain push led to the emergence of sleeves. The spiral branches themselves are waves of increased density of matter. The nature of the push can be different, one of the options is moving into stars.

Spiral branches 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 is also possible 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 haze. In size, our galaxy's neighbor is somewhat larger than it: 130,000 light-years in diameter.

The Andromeda Nebula, although the closest galaxy to the Milky Way, is vastly distant. Light takes two million years to overcome it. This fact perfectly explains why flights to the neighboring galaxy are so far only possible in science fiction books and films.

Elliptical systems

Let us now consider other types of galaxies. The photo of the elliptical system clearly demonstrates its difference from the spiral counterpart. This galaxy has no arms. It looks like an ellipse. Such systems can be compressed to varying degrees, represent something like a lens or a ball. In such galaxies, cold gas is practically not found. The most impressive representatives of this type are filled with rarefied hot gas, the temperature of which reaches a million degrees and more.

A distinctive feature of many elliptical galaxies is a reddish hue. For a long time, astronomers believed this to be a sign of the antiquity of such systems. It was believed that they were mainly composed of old stars. However, research in recent decades has shown this assumption to be false.

Education

For a long time there was another hypothesis related to elliptical galaxies. They were considered the very first of those that arose, formed shortly after the Big Bang. Today, this theory is considered obsolete. A great contribution to its refutation was made by the German astronomers Alar and Yuri Tumre, as well as the American scientist Francois Schweitzer. Their research and discoveries of recent years confirm the truth of another hypothesis, 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.

Elliptical systems, according to modern concepts, were formed from spiral systems as a result of the merging of arms. One of the confirmations of this is a large number of "twisted" galaxies observed in remote parts of space. On the contrary, in the most approximate regions, the concentration of elliptical systems, which are quite bright and extended, is noticeably higher.

Symbols

Elliptical galaxies in astronomy also received their designations. 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 of almost regular spherical shape, and E6 are the flattest.

Raging Cannonballs

Elliptical galaxies include the systems NGC 5128 from the constellation Centaurus and M87, located in Virgo. Their feature is powerful radio emission. Astronomers are primarily interested in the structure of the central part of such galaxies. Observations by Russian scientists and studies by the Hubble telescope show a rather high activity of this zone. In 1999, American astronomers obtained data on the core of the elliptical galaxy NGC 5128 (the constellation Centaur). There are huge masses of hot gas in constant motion, swirling around the center, possibly a black hole. Precise data on the nature of such processes are not yet available.

Irregular systems

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

Interaction

The main types of galaxies describe the features of the shape and arrangement of the elements of these space systems. However, the question of their interaction is no less interesting. It is no secret that all objects in space are in constant motion. Galaxies are no exception. Types of galaxies, at least some of their representatives, could have formed in the process of merging or colliding two systems.

If we remember what such objects are, it becomes clear how large-scale changes occur during their interaction. A huge amount of energy is released on impact. Interestingly, such events are even more likely in 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 counterpart, disturbing its structure in the process. This is how formations are formed that are similar in appearance to elongated corridors. They are composed of stars and gas and often become zones of 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 the assumptions of scientists, it is possible that after some, quite a long time, the Milky Way will absorb its nearest satellite, a relatively recently discovered system, tiny by space standards, located at a distance of 50 light years from us. Research evidence suggests that this moon has an impressive lifespan, which is likely to end in the process of merging with its larger neighbor.

The collision is a possible future for the Milky Way and the Andromeda Nebula. 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. The probable collision, according to scientists, will happen in three billion years. However, whether it will happen or whether the galaxies will only slightly touch each other, today no one knows for sure. For forecasting, there is not enough data on the features 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, and the future. In this area, there is still a lot of incomprehensible and requiring further study. The types of structure of galaxies are known, but there is no exact understanding of many details associated, for example, with their formation. The current pace of improvement in knowledge and technology, however, allows us to hope for significant breakthroughs in the future. In any case, galaxies will not cease to be the focus of many studies. And this is due not only to the curiosity inherent in all people. Data on cosmic patterns and life make it possible to predict the future of our piece of the Universe, the Milky Way galaxy.

The dimensions of the visible part of the Universe are simply amazing! Nevertheless, this is just a grain of sand on the shore of the boundless Ocean - the Big Universe - the true value of which we are not able to imagine or calculate ...

The Milky Way Galaxy is part of a family of neighboring galaxies known as the Local Group, and together with them forms a cluster of galaxies. Among nearby galaxies there are magnificent spirals. One of them, the Andromeda Galaxy, is the most distant object visible to the naked eye. Most galaxies in the universe are either spiral or elliptical, and many of them are part of galaxy clusters.

Throughout the 19th century and at the beginning of the 20th century. astronomers did not know exactly what kind of hazy bright spots they saw through a telescope. It was clear that stars were part of the Milky Way, as were bright gas clouds like the Orion Nebula. But in their search for comets and planets, astronomers such as Charles Messier and William Herschel found thousands of fainter nebulae, many of which were spiral. Astronomers wanted to know if they were galaxies far beyond the Milky Way or just clouds of gas in our Galaxy. The answer to this question was possible only when a method was found to measure the distances to these faint nebulae.

In 1924, the American astronomer Edwin Hubble convincingly proved that spiral nebulae are giant galaxies, similar to the Milky Way, but infinitely distant from it. With a single blow, he opened up the staggering immensity of the universe. Hubble was the first to discover variable stars in the Andromeda galaxy - Cepheids. They were much fainter than the Cepheids of the Magellanic Clouds. The difference in brightness meant that the Andromeda galaxy must be 10 times further away from us than the Magellanic Clouds.

The Andromeda Galaxy can be observed with the naked eye - it is the most distant object that can be seen without binoculars or a telescope. Countless galaxies are much fainter than this one and, therefore, even more distant from us. Edwin Hubble discovered the realm of galaxies. Over the next few years, he measured the distances to many other spirals and was able to prove that even the nearest galaxies are distant from us by many millions of light years. The dimensions of the observable universe far exceeded previous guesses.

local group

Looking into deep space, we find that galaxies are not evenly distributed throughout the universe. Galaxies cluster together to form clusters, or families. Our own family is called the "Local Group". This is, in general, a rather sparse formation: about 25 of its members are scattered over a space of 3 million light years. The largest of them are the Milky Way, as well as the spiral galaxies M31 in Andromeda and the MZZ in Triangulum. The Milky Way is accompanied by about nine dwarf galaxies moving nearby, and Andromeda has eight more. Astronomers keep finding new faint galaxies in our Local Group.

Each member of the "Local Group" moves under the influence of the gravitational attraction of all other members. All clusters of galaxies are held together by the gravitational field, which is the most important of the forces acting in the universe at large distances. By measuring the speeds of galaxies in the Local Group, astronomers can calculate its total mass. It is about 10 times larger than the mass of visible stars - hence it follows that the Local Group must contain a lot of dark, invisible matter.

Cluster in Virgo

If we continue our journey outside of the "Local Group", we will encounter other small groups of galaxies - for example, the Stefan Quintet, in which two spiral galaxies are entangled together. And then much larger clusters flicker. The huge Virgo Cluster, about 50 million light-years away, is the closest large cluster of galaxies to us. It is too far away to be able to calculate the distance using variable stars. Instead, the magnitudes of the brightest stars and the largest star clusters are used for the calculation. Their brilliance is compared with the brilliance of similar objects, the distance to which is already known.

The Virgo Cluster is huge; it is spread over an area approximately 200 times the area occupied by the full moon in the sky! There are several thousand members in this gigantic cluster. In its central part are three elliptical galaxies, first listed by Charles Messier: M84, M86 and M87. These are really huge galaxies. The largest of them, M87, is comparable in size to our entire "Local Group". The Virgo Cluster is so massive that its gravitational action not only holds this huge collective together, but also extends all the way to our "Local Group". Our Galaxy and its companions are slowly moving towards the Virgo Cluster.

Cluster in the constellation Coma Berenices

Moving even further, at a distance of about 350 million light years, we arrive at a huge galactic city in the constellation Coma Berenices. This is the Coma Cluster, containing over 1,000 bright elliptical galaxies and possibly many thousands of smaller members that are no longer visible by modern means. The size of the cluster in diameter reaches 10 million light years; two supergiant elliptical galaxies are located in its very core. Astronomers suggest that this cluster contains tens of thousands of members.

All galaxies are held together by gravity. In this case, the velocities of the galaxies within the cluster indicate that only a few percent of the total mass is contained in the stars that we can see. The Coma Veronica cluster, like other large clusters of this type, is mostly composed of dark matter.

Spiral galaxies are unlikely to exist in the central regions of densely populated clusters like that in Coma Veronica. Perhaps this is because the spiral galaxies that once existed there merged together to form elliptical galaxies. The Coma Cluster is a strong source of X-rays emitted by very hot gas with a temperature of 10 to 100 million degrees. This gas is found in the central part of the cluster; in its chemical composition, it is close to the material of stars.

It is possible that the following happened. The galaxies located in the central part of the cluster collided with each other and, scattering after the impact, shed their gas clouds. The gas was heated by friction as galaxies raced through it at speeds up to thousands of kilometers per second. As the galaxies lost their gas, their spiral arms gradually disappeared.

Superclusters and voids

Deep space photography shows that as we move into the universe, galaxies keep popping up and popping up. In almost every direction we look, there is a scattering of faint galaxies like dust. Some objects were found at a distance of up to 10 billion light years. Each of these countless galaxies contains billions of stars. Such numbers are hard to imagine even by professional astronomers. The extragalactic universe is larger than anything imaginable.

Almost all galaxies are in clusters containing from a few to many thousands of members. But what can be said about these clusters themselves: maybe they are also grouped into families? Yes, that's right!

The Local Cluster of Clusters, known as the "Local Supercluster", is a flattened formation that includes, among others, the Local Group and the Virgo Cluster. The center of mass is located in the Virgo cluster, and we are on the outskirts. Astronomers have made efforts to 3D map the Local Supercluster and reveal its structure. It turned out that it contains about 400 individual clusters of galaxies; these clusters are collected in layers and bands separated by gaps.

Another supercluster is in the constellation Hercules. Before it, about 700 million light years, and for about 300 million light years on the way to it, galaxies, apparently, do not meet at all.

Thus, astronomers have established that superclusters are separated from each other by giant empty spaces. Inside superclusters there are also like "bubbles" millions of light years in size, which do not contain galaxies. Superclusters fold into threads and ribbons, giving the universe, on the grandest scale, a spongy structure.

Hubble's law and redshift

We now know that our universe is expanding all the time, getting bigger and bigger. Hubble played a decisive role in the discovery. Using Cepheid stars, he determined the distances to the nearest galaxies, and determined their velocities from redshift measurements. The discovery was made when he plotted the speeds of galaxies as a function of their distances. It turned out that the relationship of these two quantities is expressed on the graph by a straight line: the farther the galaxy is from us, the greater its speed. Hubble law States that the faster a galaxy moves, the more distant it is. Hubble found a relationship between two quantities that could be measured for nearby galaxies: between distance and redshift (which gives speed). And after such a connection is established, Hubble's law can be reversed and used for the reverse procedure. By measuring the redshift for more distant galaxies, it is possible, using Hubble's law, to calculate the distance to them. This is how astronomers find out the distances to distant galaxies in our universe.

Of course, when using Hubble's law, there is some uncertainty about the correctness of the result. For example, if an inaccuracy is made in calculating the distances to the nearest galaxies, the graph will no longer be absolutely correct: any error in it will continue into deep space when we try to find out the distances to more distant galaxies using it. Nevertheless, Hubble's law is the most important method for studying the large-scale structure of the universe.

Universe expansion

Why does Hubble's law imply that the universe is expanding? All galaxies are moving away from us. So the Milky Way is at the center of the universe? After all, when we see an explosion - for example, a firework exploded in the sky - then everything scatters in all directions from the place of the explosion. So, if everything around us is flying away from us, we must be in the center of this expansion?

No, it is not: we are not in the center.

When, during an explosion, individual parts scatter in different directions, the distances between all the fragments increase. This means that each piece "sees" how all the others fly away from it. To understand how this works, take a balloon and draw some galaxies on it using spiral and elliptical icons. Now slowly inflate the balloon. As it expands, the galaxies move away from each other. Whatever galaxy you choose as a starting point, all the others, as the balloon is inflated, are sprayed further and further.

This can also be discussed from a mathematical point of view. The shell of the ball is a curved surface, it has almost no thickness. When you inflate a balloon, this spherical surface expands to cover more and more of the space. The curved shell, being itself two-dimensional, expands in three-dimensional space. And as this happens, the galaxies drawn on the ball are moving further and further away from each other.

As for the Universe, the three dimensions of ordinary space are expanding in some special four-dimensional space, which is called space-time. An additional dimension is time. Over time, the three dimensions of the cosmos continuously increase their length. Clusters of galaxies, inextricably linked to expanding space, are constantly moving away from each other.

Age of the Universe

How can astronomers determine the age of the universe? We find out the age of a tree by counting the annual rings on the cut - one ring grows per year. Geologists can deduce the age of rocks deposited in sediments by the fossils found in them. The age of the moon was determined by measuring the radioactivity of rocks containing radioactive elements. In all these methods, one way or another, they extract the necessary data - the number of rings, saw fossils, the intensity of the remaining radiation - and use them to calculate the age.

To determine the age of the expanding universe, we study the distance and speed of a large number of galaxies. It turns out that for every million light-years away, the speed of galaxies increases by about 20 km / s (astronomers do not know this number quite accurately, with a tolerance of 2-3 km / s). Knowing how speed changes with distance, we can calculate that 17 billion years ago all matter was in the same place. This is one way to determine the age of the universe. Since her age is the time after the Big Bang when the expansion started...

For more information about the real structure of the Universe, see the books of Academician N.V. Levashov "The Last Appeal to Mankind" and "Inhomogeneous Universe" and others.

800 trillion suns live in a distant cluster of galaxies

Ivan Terekhov, 10/17/2010

The infinite cosmos "throws" scientists more and more new, impressive details of existence at an early stage of its development. This time, astronomers from the Harvard-Smithsonian Center for Astrophysics, working with the SPT (South Pole Telecope), have discovered one of the most massive galaxy clusters, 7 billion light-years away from us. Information about the total mass of the cluster can cause bouts of dizziness and nausea when trying to assess the scale of the action: according to measurements, a star cluster has a mass equal to the mass 800 trillion suns.

The collection named SPT-CL J0546-5345, located in the constellation Pictorus. Its redshift z is 1.07, which means that astronomers are now observing the cluster in the state it was in seven billion years ago. Moreover, even then this structure was almost as large as the Coma of Veronica cluster, which is one of the densest clusters known to science. Researchers believe that over time SPT-CL J0546-5345 could have quadrupled.

“This cluster of galaxies wins the heavyweight title. This is one of the most massive clusters ever found at this distance," said Mark Brodwin of the center. (Mark Brodwin), one of the authors of an article published in "Astrophysical Journal". As Broadwin noted, SPT-CL J0546-5345 many fairly old galaxies. This means that the cluster arose in the "childhood" of the Universe, in the first two billion years of its existence. The age of the universe, according to the probe WMAP (Wilkinson Microwave Anisotropy Probe), is estimated at 13.73 billion years. Such clusters can be useful in studying the influence of dark matter and dark energy on the formation of various structures in space.

The team discovered the cluster while working with the first data from the SPT telescope installed at the Amundsen-Scott station in Antarctica. The 10-meter telescope, operating in the 70-300 GHz frequency range, began operation in 2007. The search for galaxy clusters is its main task, with the help of SPT data, scientists hope to get closer to obtaining an equation of state for dark energy, which, according to astronomers, accounts for about 74% of the mass of the Universe. Astronomers studied the found cluster using the instruments of the Spitzer space telescope (Spitzer Space Telescope), as well as the group of telescopes of the Chilean observatory Las Campanas. This made it possible to single out individual galaxies in the cluster and estimate the speed of their movement.

SPT-CL J0546-5345 was able to detect, thanks to the so-called Sunyaev-Zeldovich effect - minor distortions in the cosmic microwave background radiation, the "echo" of the Big Bang, which occur when the radiation passes through a large cluster. This search method equally well reveals both nearby and distant clusters, and also allows a fairly accurate estimate of their mass.

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There are three main types of galaxies: spiral, elliptical, and irregular. The former include, for example, the Milky Way and Andromeda. In the center are objects and a black hole around which a halo of stars and dark matter revolve. Arms branch off from the core. The spiral shape is formed due to the fact that the galaxy does not stop rotating. Many representatives have only one sleeve, but some can count three or more.

Table of characteristics of the main types of galaxies

Spiral ones come with and without a jumper. In the first type, the center is crossed by a dense bar of stars. And the second such formation is not observed.

Elliptical galaxies are home to the oldest stars and do not have enough dust and gas to create young ones. They can resemble a circle, oval or spiral type in shape, but without sleeves.

Approximately a quarter of galaxies represent a group of irregular ones. They are smaller than spiral ones and sometimes display bizarre shapes. They can be explained by the appearance of new stars or by gravitational contact with a neighboring galaxy. Among the wrong ones are .

There are also many galactic subtypes: Seyfert (spirals with fast movement), bright elliptical supergiants (absorb others), ring (without a core), and others.