Planets from other galaxies. Other solar systems of the galaxy

A galaxy is a large formation of stars, gas, dust, which are held together by the force of gravity. These largest compounds in the universe can vary in shape and size. Most of the space objects are part of a particular galaxy. These are stars, planets, satellites, nebulae, black holes and asteroids. Some of the galaxies have a lot of invisible dark energy. Due to the fact that the galaxies are separated by empty outer space, they are figuratively called oases in the cosmic desert.

	elliptical galaxy	spiral galaxy	wrong galaxy
spheroidal component	entire galaxy	Eat	Very weak
stellar disk	No or weak	Main component	Main component
Gas and dust disk	No	Eat	Eat
spiral branches	None or only near the core	Eat	No
Active cores	Meet	Meet	No
	20%	55%	5%

Our galaxy

Our closest star, the Sun, is one of the billion stars in the Milky Way galaxy. Looking at the night starry sky, it is hard not to notice a wide band strewn with stars. The ancient Greeks called the cluster of these stars the Galaxy.

If we had the opportunity to look at this star system from the side, we would have noticed an oblate ball, in which there are over 150 billion stars. Our galaxy has dimensions that are hard to imagine in your imagination. A beam of light travels from one side of it to the other for a hundred thousand Earth years! The center of our Galaxy is occupied by the core, from which huge spiral branches filled with stars depart. The distance from the Sun to the nucleus of the Galaxy is 30,000 light years. The solar system is located on the outskirts of the Milky Way.

Stars in the Galaxy, despite the huge accumulation of cosmic bodies, are rare. For example, the distance between the nearest stars is tens of millions of times greater than their diameters. It cannot be said that the stars are scattered randomly in the Universe. Their location depends on the forces of gravity that hold the celestial body in a certain plane. Star systems with their gravitational fields are called galaxies. In addition to stars, the composition of the galaxy includes gas and interstellar dust.

composition of galaxies.

The universe is also made up of many other galaxies. The closest to us are distant at a distance of 150 thousand light years. They can be seen in the sky of the southern hemisphere in the form of small hazy specks. They were first described by a member of the Magellanic expedition around the world of Pigafett. They entered science under the name of the Large and Small Magellanic Clouds.

The closest galaxy to us is the Andromeda Nebula. It has a very large size, so it is visible from the Earth with ordinary binoculars, and in clear weather - even with the naked eye.

The very structure of the galaxy resembles a giant spiral convex in space. On one of the spiral arms, ¾ of the distance from the center, is the solar system. Everything in the galaxy revolves around the central core and obeys the force of its gravity. In 1962, astronomer Edwin Hubble classified galaxies according to their shape. The scientist divided all galaxies into elliptical, spiral, irregular and barred galaxies.

There are billions of galaxies in the part of the Universe available for astronomical research. Collectively, astronomers call them the Metagalaxy.

Galaxies of the Universe

Galaxies are represented by large groupings of stars, gas, dust, held together by gravity. They can vary greatly in shape and size. Most space objects belong to a galaxy. These are black holes, asteroids, stars with satellites and planets, nebulae, neutron satellites.

Most of the universe's galaxies contain vast amounts of invisible dark energy. Since the space between different galaxies is considered empty, they are often called oases in the void of space. For example, a star called the Sun is one of the billions of stars in the "Milky Way" galaxy in our universe. At ¾ of the distance from the center of this spiral is the solar system. In this galaxy, everything is constantly moving around the central core, which obeys its gravity. However, the core also moves along with the galaxy. At the same time, all galaxies move at superspeeds.
Astronomer Edwin Hubble in 1962 carried out a logical classification of the galaxies of the universe, taking into account their shape. Now galaxies are divided into 4 main groups: elliptical, spiral, galaxies with a bar (bar) and irregular.
What is the largest galaxy in our universe?
The largest galaxy in the universe is the super-giant lenticular galaxy in the Abell 2029 cluster.

spiral galaxies

They are galaxies that in their shape resemble a flat spiral disk with a bright center (core). The Milky Way is a typical spiral galaxy. Spiral galaxies are usually called with the letter S, they are divided into 4 subgroups: Sa, So, Sc and Sb. Galaxies belonging to the So group are distinguished by bright nuclei that do not have spiral arms. As for the Sa galaxies, they are distinguished by dense spiral arms tightly wrapped around the central core. The arms of the Sc and Sb galaxies rarely surround the core.

Spiral galaxies in the Messier catalog

barred galaxies

Barred galaxies are similar to spiral galaxies, but still have one difference. In such galaxies, spirals do not start from the core, but from the bridges. About 1/3 of all galaxies fall into this category. They are usually denoted by the letters SB. In turn, they are divided into 3 subgroups Sbc, SBb, SBa. The difference between these three groups is determined by the shape and length of the bridges, from where, in fact, the arms of the spirals begin.

Messier barred spiral galaxies

elliptical galaxies

The shape of galaxies can vary from perfectly round to elongated ovals. Their distinguishing feature is the absence of a central bright core. They are designated by the letter E and are divided into 6 subgroups (by shape). Such forms are designated from E0 to E7. The former are almost round in shape, while the E7 are characterized by an extremely elongated shape.

Elliptical galaxies in the Messier catalog

Irregular galaxies

They do not have any pronounced structure or shape. Irregular galaxies are usually divided into 2 classes: IO and Im. The most common is the Im class of galaxies (it has only a slight hint of structure). In some cases, spiral remnants are traced. IO belongs to a class of galaxies that are chaotic in shape. The Small and Large Magellanic Clouds are a prime example of the Im class.

Messier catalog irregular galaxies

Table of characteristics of the main types of galaxies

	elliptical galaxy	spiral galaxy	wrong galaxy
spheroidal component	entire galaxy	Eat	Very weak
stellar disk	No or weak	Main component	Main component
Gas and dust disk	No	Eat	Eat
spiral branches	None or only near the core	Eat	No
Active cores	Meet	Meet	No
Percentage of the total number of galaxies	20%	55%	5%

Large portrait of galaxies

Not so long ago, astronomers began working on a collaborative project to determine the location of galaxies throughout the universe. Their task is to get a more detailed picture of the general structure and shape of the universe on a large scale. Unfortunately, the scale of the universe is difficult to estimate for understanding by many people. Take at least our galaxy, consisting of more than a hundred billion stars. There are billions more galaxies in the universe. Distant galaxies have been discovered, but we see their light as it was almost 9 billion years ago (we are separated by such a large distance).

Astronomers became aware that most galaxies belonged to a particular group (it became known as a "cluster"). The Milky Way is part of a cluster, which, in turn, consists of forty known galaxies. As a rule, most of these clusters are part of an even larger grouping, which is called superclusters.

Our cluster is part of a supercluster commonly referred to as the Virgo Cluster. Such a massive cluster consists of more than 2 thousand galaxies. At the same time that astronomers mapped the location of these galaxies, superclusters began to take shape. Large superclusters have gathered around what appear to be gigantic bubbles or voids. What kind of structure this is, no one knows yet. We do not understand what can be inside these voids. By assumption, they can be filled with a certain type of dark matter unknown to scientists, or they can have empty space inside. It will be a long time before we know the nature of such voids.

Galactic Computing

Edwin Hubble is the founder of galactic research. He is the first to figure out how to calculate the exact distance to a galaxy. In his research, he relied on the method of pulsating stars, which are better known as Cepheids. The scientist was able to notice the relationship between the period that is needed to complete one pulsation of brightness, and the energy that the star releases. The results of his research were a major breakthrough in the field of galactic research. In addition, he found that there is a correlation between the red spectrum emitted by a galaxy and its distance (the Hubble constant).

Nowadays, astronomers can measure the distance and speed of a galaxy by measuring the amount of redshift in the spectrum. It is known that all galaxies of the Universe move from each other. The further the galaxy is from the Earth, the greater its speed of movement.

To visualize this theory, it is enough to imagine yourself driving a car that moves at a speed of 50 km per hour. A car in front of you is driving faster at 50 km per hour, which indicates that the speed of its movement is 100 km per hour. There is another car in front of him, which is moving faster by another 50 km per hour. Even though the speed of all 3 cars will be 50 km/h different, the first car is actually moving away from you 100 km/h faster. Since the red spectrum indicates the speed of the galaxy moving away from us, the following is obtained: the greater the redshift, the faster the galaxy moves and the greater its distance from us.

Now we have new tools to help scientists in their search for new galaxies. Thanks to the Hubble Space Telescope, scientists have been able to see what they could only dream of before. The high power of this telescope provides good visibility of even small details in nearby galaxies and allows you to study more distant ones that have not yet been known to anyone. Currently, new space observation tools are under development, and in the near future they will help to gain a deeper understanding of the structure of the universe.

Types of galaxies

• spiral galaxies. In shape, they resemble a flat spiral disk with a pronounced center, the so-called core. Our Milky Way galaxy belongs to this category. In this section of the portal site you will find many different articles describing the space objects of our Galaxy.
• Barred galaxies. They resemble spiral ones, only they differ from them in one significant difference. Spirals do not depart from the core, but from the so-called jumpers. This category includes a third of all galaxies in the universe.
• Elliptical galaxies come in a variety of shapes, from perfectly round to oval-shaped. Compared to spiral ones, they lack a central, pronounced core.
• Irregular galaxies do not have a characteristic shape or structure. They cannot be attributed to any of the above types. There are far fewer irregular galaxies in the vastness of the Universe.

Astronomers have recently launched a joint project to identify the location of all galaxies in the universe. Scientists hope to get a better picture of its structure on a large scale. The size of the universe is difficult to estimate for human thinking and understanding. Our galaxy alone is a connection of hundreds of billions of stars. And there are billions of such galaxies. We can see the light from the discovered distant galaxies, but do not even mean that we are looking into the past, because the light beam reaches us for tens of billions of years, such a great distance separates us.

Astronomers also associate most galaxies with certain groups called clusters. Our Milky Way belongs to a cluster of 40 explored galaxies. Such clusters are combined into large groupings called superclusters. The cluster with our galaxy is part of the Virgo supercluster. This giant cluster contains over 2,000 galaxies. As scientists began to map the distribution of these galaxies, superclusters took on certain shapes. Most of the galactic superclusters were surrounded by giant voids. No one knows what could be inside these voids: outer space like interplanetary space or a new form of matter. It will take a long time to solve this riddle.

Interaction of galaxies

No less interesting for scientists is the question of the interaction of galaxies as components of space systems. It's no secret that space objects are in constant motion. Galaxies are no exception to this rule. Some of the types of galaxies could cause a collision or merger of two space systems. If you look into how these space objects appear, large-scale changes as a result of their interaction become more understandable. During the collision of two space systems, a huge amount of energy splashes out. The meeting of two galaxies in the vastness of the Universe is an even more probable event than the collision of two stars. The collision of galaxies does not always end in an explosion. A small space system can freely pass by its larger counterpart, changing only slightly its structure.

Thus, formations are formed that are similar in appearance to elongated corridors. Stars and gas zones stand out in their composition, new luminaries often form. There are times when galaxies do not collide, but only lightly touch each other. However, even such an interaction triggers a chain of irreversible processes that lead to huge changes in the structure of both galaxies.

What is the future of our galaxy?

As scientists suggest, it is possible that in the distant future the Milky Way will be able to absorb a tiny satellite system, which is located at a distance of 50 light years from us. Studies show that this satellite has a long life potential, but if it collides with a giant neighbor, it will most likely end its separate existence. Astronomers also predict a collision between the Milky Way and the Andromeda Nebula. Galaxies move towards each other at the speed of light. Before a likely collision, wait about three billion Earth years. However, whether it will actually happen now is hard to argue due to the lack of data on the motion of both space systems.

Description of galaxiesKvant. Space

The portal site will take you to the world of interesting and fascinating space. You will learn the nature of the construction of the Universe, get acquainted with the structure of known large galaxies and their components. By reading articles about our galaxy, some of the phenomena that can be observed in the night sky become more understandable to us.

All galaxies are at a great distance from the Earth. Only three galaxies can be seen with the naked eye: the Large and Small Magellanic Clouds and the Andromeda Nebula. It is impossible to count all galaxies. Scientists suggest that their number is about 100 billion. The spatial arrangement of galaxies is uneven - one region can contain a huge number of them, in the second there will not be even a single small galaxy at all. Astronomers failed to separate the image of galaxies from individual stars until the early 1990s. At that time, there were about 30 galaxies with individual stars. All of them were assigned to the Local group. In 1990, a majestic event took place in the development of astronomy as a science - the Hubble telescope was launched into Earth's orbit. It is this technique, as well as new ground-based 10-meter telescopes, that made it possible to see a much larger number of resolved galaxies.

Today, the "astronomical minds" of the world are puzzling over the role of dark matter in the construction of galaxies, which manifests itself only in gravitational interaction. For example, in some large galaxies it makes up about 90% of the total mass, while dwarf galaxies may not contain it at all.

Evolution of galaxies

Scientists believe that the emergence of galaxies is a natural stage in the evolution of the Universe, which took place under the influence of gravitational forces. Approximately 14 billion years ago, the formation of protoclusters in the primary matter began. Further, under the influence of various dynamic processes, the separation of galactic groups took place. The abundance of galaxy shapes is explained by the variety of initial conditions in their formation.

It takes about 3 billion years to compress a galaxy. Over a given period of time, the gas cloud turns into a star system. Star formation occurs under the influence of gravitational compression of gas clouds. After reaching a certain temperature and density in the center of the cloud, sufficient for the start of thermonuclear reactions, a new star is formed. Massive stars are formed from thermonuclear chemical elements that are larger than helium in mass. These elements create the primary helium-hydrogen environment. During grandiose explosions of supernovae, elements heavier than iron are formed. It follows from this that the galaxy consists of two generations of stars. The first generation are the oldest stars, consisting of helium, hydrogen and a very small amount of heavy elements. Second-generation stars have a more noticeable admixture of heavy elements, since they are formed from a primordial gas enriched in heavy elements.

In modern astronomy, galaxies as cosmic structures are given a separate place. The types of galaxies, the features of their interaction, similarities and differences are studied in detail, and a forecast of their future is made. This area contains many more incomprehensible things that require further study. Modern science has solved many questions regarding the types of construction of galaxies, but there are also many blank spots associated with the formation of these cosmic systems. The current pace of modernization of research equipment, the development of new methodologies for the study of space bodies give hope for a significant breakthrough in the future. One way or another, galaxies will always be at the center of scientific research. And it is based not only on human curiosity. Having received data on the patterns of development of space systems, we will be able to predict the future of our galaxy called the Milky Way.

The most interesting news, scientific, author's articles about the study of galaxies will be provided to you by the portal site. Here you can find breathtaking videos, high-quality images from satellites and telescopes that do not leave you indifferent. Dive into the world of unknown space with us!

Those who have little understanding of the universe know well that the cosmos is constantly in motion. The universe is expanding every second, getting bigger and bigger. Another thing is that on the scale of human perception of the world, it is quite difficult to realize the dimensions 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, there are dozens, hundreds of other galaxies. No one knows the exact number of distant worlds. How many galaxies in the universe can only be known approximately by creating a mathematical model of the cosmos.

Therefore, given the size of the Universe, one can easily assume the idea that in a dozen, a hundred billion light-years from Earth, there are worlds similar to ours.

Space and the worlds that surround us

Our galaxy, which received the beautiful name "Milky Way", several centuries ago, according to many scientists, was the center of the universe. In fact, it turned out that this is only a 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 a designated place. Planets known to us, well-known stars, black holes and our solar system itself are located in the Milky Way galaxy. The name is not accidental. Even ancient astronomers who observed the night sky compared the space around us with a milk path, where thousands of stars look like drops of milk. The Milky Way Galaxy, the celestial galactic objects that are in our field of vision, make up the nearest space. What could be beyond the visibility of telescopes became known only in the 20th century.

Subsequent discoveries, which increased our cosmos to the size of the Metagalaxy, prompted 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 rudiments of the Universe began to form - protogalaxies consisting of stars. All this happened in the distant past. The light of many heavenly bodies, which we can observe in the strongest telescopes, is only a farewell greeting. The millions of stars, if not billions, that strewn our sky are a billion light-years from Earth, and have long since ceased to exist.

Map of the Universe: Nearest and Farthest Neighbors

Our solar system, other cosmic bodies observed from the Earth are relatively young structural formations and our closest neighbors in the vast Universe. For a long time, scientists believed that the closest dwarf galaxy to the Milky Way was the Large Magellanic Cloud, located just 50 kiloparsecs away. 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, the mass of which 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 collide. When this will happen and how it will turn out, we can only speculate. The collision of galaxies has been going on 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. Among astronomers and astrophysicists, it continues to be one of the most popular and is located only 2.52 million light years from Earth. Like our galaxy, Andromeda is a member of the Local Group of Galaxies. This gigantic cosmic stadium is three million light-years across, and contains about 500 galaxies. However, even a giant like Andromeda looks small compared to 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 the fact that it includes 100 trillion stars, the galaxy is mainly composed of dark matter.

Astrophysical parameters and types of galaxies

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

An American astronomer for the first time suggested that our Universe is a lot of galaxies. Space exploration in the last quarter of the 20th century, observations made with the help of spacecraft and technology, including the famous Hubble telescope, confirmed these assumptions. Space is limitless, and our Milky Way is far from being the largest galaxy in the Universe, and besides, it is not its center.

Only with the advent of powerful technical means of observation, the Universe began to take on a clear outline. 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;
• wrong.

Elliptical galaxies 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 of the directions. These objects lack sleeves and often change their shape. These objects also differ in size from each other. Unlike spiral galaxies, these cosmic monsters do not have a distinct center. There is no nucleus 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 round galaxies (E0, E1 and E2) to strongly stretched objects with indices E6 and E7. Among elliptical galaxies, there are dwarfs and real giants with diameters of millions of light years.

There are two types of spiral galaxies:

• galaxies represented as 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 bar (bar), which gives rise to arms. Such bridges in the galaxy are usually the result of physical centrifugal processes that divide the core of the galaxy into two parts. There are galaxies with two nuclei, the tandem of which makes up the central disk. When the nuclei meet, the bar disappears and the galaxy becomes normal, with one center. There is a jumper in our Milky Way galaxy, in one of the arms of which our solar system is located. According to modern estimates, the path from the Sun to the center of the galaxy is 27 thousand light years. The thickness of the arm of Orion Cygnus, in which our Sun resides and our planet along with it, 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 galaxy "Milky Way" is in the "golden mean", with its size gravitating towards 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 and structure. In accordance with the classification, they received indices Im and IO. As a rule, structures of the first type do not have a disk or it is poorly expressed. Often, such galaxies can be seen like arms. Galaxies with indices IO are a chaotic cluster of stars, clouds of gas and dark matter. Bright representatives of such a group of galaxies are the Large and Small Magellanic Clouds.

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

Based on the existing classification and the results of research, it is possible with some degree of certainty to answer the question of how many galaxies in the Universe and what type they are. Most of all in the universe of spiral galaxies. They are 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 adjacent to us and are in the field of view of the most powerful telescopes. Others are in the farthest space, where dark matter prevails and the lens shows more blackness of the boundless space.

Galaxies up close

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

The map of the Universe, which astronomers are guided by today, gives an idea of ​​how the Universe looks like, what is its shape and structure. All clusters gather around voids or dark matter bubbles. It is possible to think 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.

The current and future state of galaxies

Scientists believe that it is impossible to make a general portrait of the universe. We have visual and mathematical data about the cosmos, which is within our understanding. It is impossible to imagine the real scale of the Universe. What we see through a telescope is the light of stars that has been coming to us for billions of years. Perhaps the real picture today is completely different. The most beautiful galaxies in the Universe as a result of cosmic cataclysms 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 that exists in the neighborhood. What will be the consequences of such universal changes, one can only guess. 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 remain before the fatal collision. Whether there will be life 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 able to swallow a star. Where is the guarantee that such enormous monsters, hiding in dark matter and in the voids of space, will not be able to swallow the galaxy entirely.

Planet Earth, solar system, and all stars visible to the naked eye are in Milky Way Galaxy, which is a barred spiral galaxy with two distinct arms beginning at the ends of the bar.

This was confirmed in 2005 by the Lyman Spitzer Space Telescope, which showed that our galaxy's central bar is larger than previously thought. spiral galaxies barred - spiral galaxies with a bar ("bar") of bright stars, emerging from the center and crossing the galaxy in the middle.

Spiral arms in such galaxies start at the ends of the bars, while in ordinary spiral galaxies they emerge directly from the core. Observations show that about two-thirds of all spiral galaxies are barred. According to existing hypotheses, the bars are centers of star formation that support the birth of stars in their centers. It is assumed that through orbital resonance, they pass gas from the spiral branches through them. This mechanism provides the influx of building material for the birth of new stars. The Milky Way, together with the Andromeda (M31), Triangulum (M33), and over 40 smaller satellite galaxies, form the Local Group of Galaxies, which in turn is part of the Virgo Supercluster. "Using infrared imaging from NASA's Spitzer telescope, scientists have discovered that the Milky Way's elegant spiral structure has only two dominant arms from the ends of the central bar of stars. Our galaxy was previously thought to have four main arms."

/s.dreamwidth.org/img/styles/nouveauoleanders/titles_background.png" target="_blank">http://s.dreamwidth.org/img/styles/nouveauoleanders/titles_background.png) 0% 50% no-repeat rgb(29, 41, 29);"> Structure of the Galaxy
In appearance, the galaxy resembles a disk (since the bulk of the stars are located in the form of a flat disk) with a diameter of about 30,000 parsecs (100,000 light years, 1 quintillion kilometers) with an estimated average disk thickness of about 1000 light years, a bulge diameter of the center of the disk is 30,000 light years. The disk is immersed in a spherical halo, and around it is a spherical corona. The center of the nucleus of the Galaxy is located in the constellation Sagittarius. The thickness of the galactic disk in the place where it is located solar system with the planet Earth, is 700 light years. The distance from the Sun to the center of the Galaxy is 8.5 kilo parsecs (2.62.1017 km, or 27,700 light years). solar system is located on the inner edge of the arm, which is called the arm of Orion. In the center of the Galaxy, apparently, there is a supermassive black hole (Sagittarius A *) (about 4.3 million solar masses) around which, presumably, a black hole of average mass from 1000 to 10,000 solar masses rotates with an orbital period of about 100 years and several thousand relatively small ones. The galaxy contains, according to the lowest estimate, about 200 billion stars (modern estimates range from 200 to 400 billion). As of January 2009, the mass of the Galaxy is estimated at 3.1012 solar masses, or 6.1042 kg. The main mass of the Galaxy is contained not in stars and interstellar gas, but in a non-luminous halo of dark matter.

Compared to the halo, the disk of the Galaxy rotates noticeably faster. The speed of its rotation is not the same at different distances from the center. It rapidly increases from zero at the center to 200–240 km/s at a distance of 2,000 light-years from it, then decreases somewhat, increases again to approximately the same value, and then remains almost constant. The study of the features of the rotation of the disk of the Galaxy made it possible to estimate its mass, it turned out that it is 150 billion times greater than the mass of the Sun. Age Milky Way galaxy equals13,200 million years old, almost as old as the universe. The Milky Way is part of the Local Group of Galaxies.

/s.dreamwidth.org/img/styles/nouveauoleanders/titles_background.png" target="_blank">http://s.dreamwidth.org/img/styles/nouveauoleanders/titles_background.png) 0% 50% no-repeat rgb(29, 41, 29);"> Solar System Location solar system is located on the inner edge of the arm called the Orion arm, in the outskirts of the Local Supercluster (Local Supercluster), which is sometimes also called the Virgo Supercluster. The thickness of the galactic disk (in the place where it is located solar system with the planet Earth) is 700 light years. The distance from the Sun to the center of the Galaxy is 8.5 kilo parsecs (2.62.1017 km, or 27,700 light years). The sun is located closer to the edge of the disk than to its center.

Together with other stars, the Sun revolves around the center of the Galaxy at a speed of 220-240 km / s, making one revolution in about 225-250 million years (which is one galactic year). Thus, for the entire time of its existence, the Earth flew around the center of the Galaxy no more than 30 times. The galactic year of the Galaxy is 50 million years, the orbital period of the jumper is 15-18 million years. In the vicinity of the Sun, it is possible to track sections of two spiral arms that are about 3 thousand light years away from us. According to the constellations where these areas are observed, they were given the name of the Sagittarius arm and the Perseus arm. The sun is located almost in the middle between these spiral arms. But relatively close to us (by galactic standards), in the constellation of Orion, there is another, not very clearly defined arm - the Orion arm, which is considered an offshoot of one of the main spiral arms of the Galaxy. The speed of rotation of the Sun around the center of the Galaxy almost coincides with the speed of the compression wave that forms the spiral arm. This situation is atypical for the Galaxy as a whole: the spiral arms rotate at a constant angular velocity, like spokes in wheels, and the movement of stars occurs with a different pattern, so almost the entire stellar population of the disk either gets inside the spiral arms or falls out of them. The only place where the speeds of stars and spiral arms coincide is the so-called corotation circle, and it is on this circle that the Sun is located. For the Earth, this circumstance is extremely important, since violent processes occur in the spiral arms, which form powerful radiation that is destructive to all living things. And no atmosphere could protect him from it. But our planet exists in a relatively quiet place in the Galaxy and has not been affected by these cosmic cataclysms for hundreds of millions (or even billions) of years. Perhaps that is why on Earth could be born and survive life, whose age is counted in 4.6 billion years. A diagram of the location of the Earth in the universe in a series of eight maps that show, from left to right, starting from the Earth, moving into solar system, to neighboring star systems, to the Milky Way, to local Galactic groups, tolocal superclusters of Virgo, at our local super cluster, and ends in the observable universe.

Solar system: 0.001 light years

Neighbors in interstellar space

Milky Way: 100,000 light years

Local Galactic Groups

Virgo Local Super Cluster

Local over clusters of galaxies

observable universe

The universe is huge and fascinating. It is difficult to imagine how small the Earth is compared to the abyss of space. According to the most cautious assumptions of astronomers, there are 100 billion galaxies, and the Milky Way is just one of them. As for the Earth, there are 17 billion such planets in the Milky Way alone... and that's not counting others that are radically different from our planet. And among the galaxies that have become known to scientists today, there are very unusual ones.

1. Messier 82

Messier 82 or simply M82 is a galaxy five times brighter than the Milky Way. This is due to the very rapid process of the birth of young stars in it - they appear 10 times more often than in our galaxy. The red plumes emanating from the center of the galaxy are glowing hydrogen ejected from the center of M82.

2. Sunflower Galaxy

Formally known as Messier 63, this galaxy has been nicknamed the Sunflower because it looks like it stepped out of a Vincent van Gogh painting. Its bright, sinuous "petals" are made up of newly formed blue-white giant stars.

3. MACS J0717

MACS J0717 is one of the strangest galaxies known to scientists. Technically, this is not a single stellar object, but a cluster of galaxies - MACS J0717 was formed when four other galaxies collided. Moreover, the collision process has been going on for more than 13 million years.

4. Messier 74

If Santa Claus had a favorite galaxy, it would clearly be Messier 74. It is often remembered by astronomers during the Christmas holidays, because the galaxy is very similar to the Christmas wreath.

5. Baby Boom Galaxy

Located about 12.2 billion light-years from Earth, the baby boom galaxy was discovered in 2008. She got her nickname due to the fact that new stars are born incredibly quickly in her - about every 2 hours. For example, in the Milky Way, a new star appears on average every 36 days.

6 Milky Way

Our Milky Way Galaxy (which contains the Solar System, and, accordingly, the Earth) is indeed one of the most remarkable galaxies known to scientists in the Universe. It contains at least 100 billion planets and about 200-400 billion stars, some of which are among the oldest in the known universe.

7. IDCS 1426

Thanks to the cluster of galaxies IDCS 1426, today you can see what the Universe used to be two-thirds younger than it is now. IDCS 1426 is the most massive cluster of galaxies in the early universe, with a mass of about 500 trillion suns. The bright blue core of a galaxy of gas is the result of a collision of galaxies in this cluster.

8. I Zwicky 18

The dwarf blue galaxy I Zwicky 18 is the youngest known galaxy. She is only 500 million years old (the age of the Milky Way is 12 billion years) and is essentially in the state of an embryo. This is a giant cloud of cold hydrogen and helium.

9. NGC 6744

NGC 6744 is a large spiral galaxy that is (according to astronomers) one of the most similar to our Milky Way. The galaxy, located about 30 million light-years from Earth, has an elongated core and spiral arms that are surprisingly identical to the Milky Way.

10 NGC 6872

The galaxy, known as NGC 6872, is the second largest spiral galaxy ever discovered by scientists. Many regions of active star formation have been found in it. Since NGC 6872 has practically no free hydrogen left for star formation, it "sucks" it from the neighboring galaxy IC 4970.

11. MACS J0416

Found 4.3 billion light-years from Earth, the MACS J0416 galaxy looks more like some kind of light show at a fancy disco. In fact, behind the bright purple and pink colors lies an event of colossal proportions - a collision of two clusters of galaxies.

12. M60 and NGC 4647 - a galactic pair

Although gravitational forces pull most galaxies towards each other, there is no evidence that this is happening to neighboring Messier 60 and NGC 4647. There is also no evidence that they are moving away from each other. Like a couple living together for a long time, these two galaxies race side by side through cold and dark space.

13. Messier 81

Located near Messier 25, Messier 81 is a spiral galaxy with a supermassive black hole at its center, with a mass 70 million times that of the Sun. M81 is home to many short lived but very hot blue stars. The gravitational interaction with M82 has led to plumes of hydrogen gas stretching between both galaxies.

About 600 million years ago, the galaxies NGC 4038 and NGC 4039 crashed into each other, starting to massively exchange stars and galactic matter. Because of their appearance, these galaxies are called antennas.

15. Sombrero Galaxy

The Sombrero Galaxy is one of the most popular among amateur astronomers. It got its name from the fact that, thanks to its bright core and large central bulge, it looks like this headdress.

16.2MASX J16270254+4328340

This blurry galaxy in all the images is known under the rather complicated name 2MASX J16270254 + 4328340. As a result of the merger of the two galaxies, a "fine fog consisting of millions of stars" was formed. This "fog" is thought to be slowly dissipating as the galaxy's lifespan expires.

17. NGC 5793

Not too strange (although very beautiful) at first glance, the spiral galaxy NGC 5793 is better known for its rare phenomenon: masers. People are familiar with lasers that emit light in the visible region of the spectrum, but few people know about masers that emit light in the microwave range.

18. Triangulum Galaxy

This photo shows the nebula NGC 604, located in one of the spiral arms of the Messier 33 galaxy. More than 200 very hot stars heat the ionized hydrogen in this nebula, which causes it to fluoresce.

19. NGC 2685

NGC 2685, also sometimes referred to as a spiral galaxy, lies in the constellation Ursa Major. One of the first polar ring galaxies to be found, NGC 2685 has an outer ring of gas and stars orbiting the galaxy's poles, making it one of the rarest galaxies. Scientists still don't know what causes these polar rings to form.

20. Messier 94

Messier 94 looks like a terrible hurricane that was removed from orbit on Earth. This galaxy is surrounded by bright blue rings of actively forming stars.

21. Pandora Cluster

Formally known as Abell 2744, this galaxy has been nicknamed the Pandora Cluster due to a number of strange phenomena resulting from the collision of several smaller clusters of galaxies. It's a real chaos.

22. NGC 5408

What looks more like a colorful birthday cake in the pictures is an irregular galaxy in the constellation Centaurus. It is notable for the fact that it emits super-powerful X-rays.

23. Whirlpool Galaxy

The Whirlpool Galaxy, officially known as M51a or NGC 5194, is large enough and close enough to the Milky Way to be visible in the night sky even with binoculars. It was the first spiral galaxy to be classified and is of particular interest to scientists due to its interaction with the dwarf galaxy NGC 5195.

24. SDSS J1038+4849

The galaxy cluster SDSS J1038+4849 is one of the most attractive clusters ever found by astronomers. It looks like a real smiley in space. The eyes and nose are galaxies, and the curved line of the "mouth" is due to the effects of gravitational lensing.

25. NGC3314a and NGC3314b

Although these two galaxies look like they are colliding, this is actually an optical illusion. There are tens of millions of light years between them.

The first exoplanet - a planet outside the solar system and orbiting another star in our galaxy - was discovered by astronomers about 20 years ago. Over the past 15 years, experimental technologies for observing the starry sky have improved significantly, and to date, scientists have managed to observe about 500 exoplanets, some of which are . However, it has not yet been possible to detect planets belonging to stars outside the Milky Way. Planets are very small and dim compared to stars, making them much more difficult to observe.

Astronomers at the European Southern Observatory (ESO, Chile) reported in a journal article Science about the observation of the first such planet. Although now this planet and its star are within the Milky Way, scientists have every reason to believe that it was born in deep space. Thus,

Scientists have discovered the first extragalactic exoplanet.

The planet HIP 13044 b has a mass of about 1.25 that of Jupiter and orbits a dying star from a dwarf galaxy that has been swallowed up by the Milky Way. The planet is unique for another reason: its stars are now experiencing the same “old age” that awaits the Sun.

For most of a star's life, the process by which we now obtain energy from the Sun takes place in it: the thermonuclear fusion of helium from hydrogen. But when hydrogen “burns out”, helium and other heavier elements begin to “burn out”, as a result, the star increases significantly in size and turns into a red giant. It is assumed that when the Sun reaches this stage of life, it will absorb the planets closest to it. New observations of the star HIP 13044 are consistent with this: it rotates unusually fast for stars of its class. Perhaps this means that, having become a red giant, it just swallowed the nearest planets of its system.

Depending on the mass of the star, its fate after the stage of the red giant may be different: the processes of "burning" may stop - small stars, like the Sun, turn into so-called white dwarfs. Massive stars end their lives as neutron stars or black holes. The planetary systems of these stars in the later stages of life (in particular, those that survived the stage of a red giant) are still very poorly understood.

“We would like to understand how the discovered planet can survive the stage of the red giant of its star. This will open a window for us to the distant future of the solar system,”

The "intergalactic guest" was discovered using data from the FEROS spectrograph mounted on the 2.2-meter MPG/ESO telescope at the La Silla Observatory.

The star HIP 13044 is separated from the Earth by about 2.2 thousand light years. It is located in the constellation Furnace and is part of the so-called Helmi Stream, a group of stars that originally belonged to a small galaxy that became part of the Milky Way about 6-8 billion years ago.

In the chemical composition of the "alien" there are almost no chemical elements heavier than helium. This is typical for ancient stars that arose during the "youth" of the Universe. Heavy elements appeared as a result of active nuclear fusion in very large stars and spread through space as a result of supernova explosions (after that, a neutron star or a black hole remains at the site of the explosion). Scientists still cannot figure out how such a “light” star could form a planet around itself. More than 90% of exoplanets known to astronomers are found in “heavy” stars with a high content of metals, and finding a planet around such a “primordial” star was extremely surprising, Setyavan noted.

Most likely, this is not a solid terrestrial planet, but a gas giant.

The authors of the work note that this is the first reliable discovery of an exoplanet that originated in another galaxy. About the discovery of an exoplanet in the Andromeda galaxy back in 2009, but then it was only an interpretation of the data of a single experiment. This object was discovered by gravitational microlensing, when scientists analyze the fluctuations in the distortion of light from distant stars caused by the gravity of the star-planet system and, thus, the planet. “There is no chance to repeat these measurements, microlensing is a single event. Therefore, this statement cannot be confirmed, ”the authors of the new work note.

The signal of the planet HIP 13044 b, on the other hand, is very clear and reproducible. Astronomers believe that in the near future, independent and more accurate measurements will give full confirmation that this is indeed an extragalactic exoplanet.