How many galaxies in the Universe are known to modern man? How many galaxies are there in the universe
Our ancestors thought that the Earth was the whole World, and the Sun and Moon revolved around the planet. With the development of science, these boundaries expanded, first to the limits of the Solar System, then to the Galaxy. Milky Way. Today scientists face more than difficult questions: where is the boundary of the Universe and how many Galaxies are there?
Scientists realized that the “nebulas” that astronomers saw in the night sky were other galaxies that had nothing to do with our native one only in the 20s of the last century.
The most important role in this discovery was played by one of the founders of modern astronomy, American Edwin Hubble, after whom NASA's main space telescope Hubble was named.
It is also worth noting that until the beginning of the 21st century, galaxies were considered to be clusters with the number of stars ranging from several million to tens and even hundreds of trillions. The latter are classified as “supergiant galaxies,” but, besides them, there are much larger structures in space! In particular, scientists have identified numerous “galaxy clusters” - groups of hundreds of galaxies gravitationally connected to each other, “superclusters” - galactic superclusters uniting “ordinary” clusters, and, finally, “mega-monsters” - galactic filaments (another name for them is “Great walls”), complex structures extending in outer space for hundreds of millions and even several billion light years, which include hundreds of galaxy clusters and superclusters, as well as the voids separating them.
Moreover, relatively recently, astronomers began to find much smaller galactic communities; for example, in 2003, microgroups (so-called “ultracompact dwarf galaxies”) were discovered, uniting only a few hundred stars. Thus, at present there is a strong diversity of opinions both on the issue of defining clear physical boundaries between galaxies and “galaxy clusters” and on whether it is possible to quantitatively limit the minimum permissible number of star systems that make up a single galaxy.
Everything is not so simple with the scientific classification of the main types and types of galaxies, more precisely, their shapes and spatial outlines.
The first serious attempt to sort galaxies was made by the same Edwin Hubble, who compiled a special diagram in the 20-30s of the last century, which later received the name “Hubble’s tuning fork.” He divided all galaxies into four main types - elliptical(with an elongated spherical shape), spiral(disc galaxies similar to flat pancakes and having several branches-twirls - our Milky Way belongs precisely to this category), lenticular(similar in shape to spiral ones, but without arms-processes) and "wrong", that is, not amenable to clear visual classification. Hubble himself believed that all these types smoothly flow into each other over time, and the most ancient are elliptical, while others were formed later as a result of spatial mutations. Accordingly, its diagram looked like a tuning fork with two teeth: on its base leg there were elliptical galaxies, and on its continuation teeth – lenticular and spiral ones, while the “irregular” ones were generally designated separately.
This original version of it subsequently underwent serious correction and was supplemented by many intermediate and transitional types. Moreover, scientists currently believe that there is no evolutionary logic in the development of various forms there were, apparently, no galaxies at all. Thus, in the early stages of the expansion of the Universe, both elliptical and spiral/lenticular galaxies could form, and, according to one of the popular hypotheses, most of the most ancient galaxies had irregular outlines.
It is worth noting that many new information O different forms and the ages of galaxies scattered throughout the Universe was obtained quite recently - in the 90s of the last century and at the beginning of this century, and much of the credit for this belongs to the Hubble Space Telescope, launched into low-Earth orbit in 1990. For more than 20 years, Hubble has taken a huge number of photographs of distant star clusters and identified thousands of previously unknown galaxies in a number of regions of the Universe.
In the latest time research program Frontier Fields using the Hubble telescope to study the most ancient sites starry sky. And at the end of 2015 after analysis next episode Hubble images and more space telescope Spitzer, American astronomers have identified the oldest galaxy to date, which apparently formed just 400 million years after the Big Bang.
How are galaxies born?
Despite the enormous progress achieved by galactic astronomy in the second half of the twentieth century and beginning of XXI centuries, still remains unresolved whole line fundamental problems related primarily to the physical mechanisms of formation and subsequent development of these large-scale cosmic structures.
According to modern calculations, the estimated age of the Universe, that is, the time that has passed since the Big Bang, is about 13 billion 800 million years. Scientists currently believe that the first galaxies in the Universe began to form several hundred million years after the Big Bang. Moreover, until quite recently it was believed that this process was started later, approximately a billion years after the “beginning of time.”
Thanks to the rapid improvement of scientific equipment in the era of the ICT revolution, astronomers have managed to rewind the history of the Universe far back, but even the most powerful telescopes today are not yet able to discern the light from very dim cosmic objects formed in the earliest stages of its evolution.
Therefore, theoretical scientists mostly have to deal with constructing various hypotheses and mathematical models that explain the specifics of galactogenesis. In principle, modern computer technologies already make it possible to calculate in detail various physical scenarios of this process, but in order to obtain the correct picture, first it is necessary, at a minimum, to understand what the notorious dark matter is. Dark matter appears to be a key participant in galactogenesis, and without a clear understanding of its role in this process, scientists are unlikely to be able to develop truly effective and functional computer models. Another unclear element of this puzzle is black holes, or rather the degree of their participation in the birth and further growth of galaxies. According to scientists, these colossal clumps of matter are hidden in the central zones of most galaxies.
In the meantime, the most popular among theorists is the hypothesis according to which, as a result of the ultra-fast expansion of the young Universe, heterogeneous clots (lumps) of matter accumulated in large quantities, which gradually, under the influence of mutual gravity, united with each other into increasingly massive structures (at first - into separate stars, and then into star clusters, the embryos of future galaxies). Special attention the scheme of galactogenesis also focuses on possible scenarios for participation in this process dark matter, which most likely acted as the main cementing material that gravitationally retained the new formations that arose in different regions Universe.
Filming in live
One of the most important scientific directions is the study of the processes of merger and association with each other of mature galaxies observed by our instruments “in real time” (of course, adjusted for the obvious fact that observation instruments, recording signals coming to us on Earth, see these objects as they are were in the very distant past).
For several billion years after the Big Bang, the formed galaxies of various shapes and types regularly increased their mass and volume, mostly sucking gas and dust particles from the surrounding outer space. However, gradually this “no man’s material” in the Universe became scarce and the average rate of increase in the mass of stellar matter in mature galaxies fell sharply. Therefore, the main resource for replenishing the material reserves of galaxies in the later stages of evolution turned out to be the smaller star clusters closest to them.
The dwarf elliptical galaxy in the constellation Sagittarius is one of the two unlucky neighbors of the Milky Way, which our galaxy is gradually absorbing into itself, feeding on new raw materials supplied from outside. Its second victim known to science is another mini-galaxy in the constellation Canis Major, which the Milky Way has already almost completely digested: according to astronomical observations, only “horns and legs” (stars preserved in its former central core zone) have remained from it to date. In more ancient times, according to scientists, the Milky Way managed to successfully feast on at least eight other small galaxies. However, in the distant future, in about 4 billion years, our galaxy will face a very unpleasant meeting with an even larger neighbor than it, the Andromeda galaxy. According to theorists' calculations, after another two billion years after this rapprochement, the Milky Way and Andromeda should merge into one large elliptical galaxy.
Everyone has ever thought about how large and unknown the world around us is. Being part of an immeasurably vast Universe, we often and with curiosity ask ourselves questions: “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 on general knowledge and ideas about 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. They are the ones who are trying to answer the question of what the cosmos is made of or how many galaxies there are in the Universe. From its very first days, philosophy has been studying the Universe in subjective reality. The mother of all sciences is not concerned about how many galaxies there are in the Universe, but about how it and its 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 much large quantity questions remain unanswered. Only a small part of the Universe can be physically studied at a certain point in time; we can only guess about the rest. The past and future of the Universe are only assumptions and predictions, and its present is revealed to us only to a tiny fraction.
What do we know for sure 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 distances between cosmic objects, a completely “universal” unit is used - the light year. This is the distance that a beam of light can travel 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 covered in 100 thousand light years.
Scientists divide cosmic matter into a cluster of atoms - 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 considerable part of the visible space of the Universe is occupied by 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 moving away from each other. It is impossible to answer the question of how many galaxies there are in the Universe with precision.
What can we only guess?
The past of the Universe and the process of its formation are precisely unknown. Scientists suggest that the Universe is almost 14 billion years old and formed after the expansion of concentrated hot matter, which in cosmology is called the Big Bang Theory.
Scientists obtain everything on which the main theoretical models of the evolution of the Universe are based 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 for many reasons. Therefore, it is worth concentrating on accessible and proven knowledge that answers the questions about how many stars are in the galaxy, and how many galaxies are in the Universe. Photo taken with modern technologies, called Hubble (for 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. Gravitational interaction 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 may be 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 existence of two identical galaxies is unlikely. By type they are divided into:
- elliptical;
- spiral;
- lenticular;
- with jumper;
- incorrect.
Based on their size, galaxies are classified as dwarf, medium, large and giant. There is no clear 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 the stars, the size of the galaxy, and many others.
Scale of galaxies
Every 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 clouds of stars called superclusters of galaxies. The gravitational interdependence of galaxies in relation to their 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 its 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 the 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 dark matter spaces in the Virgo Supercluster as there are galaxies. The exact number of stars in the Milky Way is unknown, but according to rough estimates there are 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 located closer to the surface of the disk, while the center of the galactic 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 located in the shape of a disk. The most heavy element The system is its center - the Sun, which accounts for almost all the mass, which determines the strong gravitational attraction. The eight planets orbiting it make up just 0.14% of the system's total mass. Earth belongs to the four small planets terrestrial group, along with Mars, Venus and Mercury. The remaining planets are called gas giants because they consist mostly of gases.
The outer space around us is not just lonely stars, planets, asteroids and comets sparkling in the night sky. Space is a huge system where everything is in close interaction with each other. Planets are grouped around stars, which in turn gather into a cluster or nebula. These formations can be represented by single luminaries, or they can number hundreds, thousands of stars, forming larger-scale universal formations - galaxies. Our star country, the Milky Way galaxy, is only a small part of the vast Universe, in which other galaxies also exist.
Starry sky
The universe is constantly in motion. Any object in space is part of a particular galaxy. Following the stars, galaxies also move, each of which has its own size, a specific place in the dense universal order and its own trajectory of movement.
What is the real structure of the Universe?
For a long time, humanity's scientific ideas about space were built around the planets of the solar system, stars and black holes that inhabit our planet. star house– the Milky Way galaxy. Any other galactic object detected in space using telescopes was automatically included in the structure of our galactic space. Accordingly, there was no idea that the Milky Way is not the only universal formation.
Edwin Hubble
Limited technical capabilities did not allow us to look further, beyond the Milky Way, where, according to conventional wisdom, the void begins. Only in 1920, the American astrophysicist Edwin Hubble was able to find evidence that the Universe is much larger and, along with our galaxy, there are other, large and small galaxies in this huge and endless world. There is no real boundary of the Universe. Some objects are located quite close to us, only a few million light years from Earth. Others, on the contrary, are located in the far corner of the Universe, being out of sight.
Almost a hundred years have passed and the number of galaxies today is already estimated at hundreds of thousands. Against this background, our Milky Way looks not at all so huge, if not quite tiny. Today, galaxies have already been discovered whose dimensions are difficult even to determine. mathematical analysis. For example, the largest galaxy in the Universe, IC 1101, has a diameter of 6 million light years and consists of more than 100 trillion stars. This galactic monster is located more than a billion light years from our planet.
Size comparison
The structure of such a huge formation, which is the Universe on a global scale, is represented by emptiness and interstellar formations - filaments. The latter, in turn, are divided into superclusters, intergalactic clusters and galactic groups. The smallest link of this huge mechanism is the galaxy, represented by numerous star clusters - arms and gas nebulae. It is assumed that the Universe is constantly expanding, thereby causing galaxies to move at tremendous speed in the direction from the center of the Universe to the periphery.
If we imagine that we are observing space from our Milky Way galaxy, which is supposedly located at the center of the universe, then a large-scale model of the structure of the Universe will look like this.
Dark matter - aka emptiness, superclusters, clusters of galaxies and nebulae - are all the consequences of the Big Bang, which marked the beginning of the formation of the Universe. Over the course of a billion years, its structure undergoes a transformation, the shape of galaxies changes, as some stars disappear, swallowed up by black holes, while others, on the contrary, transform into supernovae, becoming new galactic objects. Billions of years ago, the arrangement of galaxies was completely different from what we see now. One way or another, against the background of constant astrophysical processes occurring in space, we can draw certain conclusions that our Universe does not have a constant structure. All space objects are located in constant movement, changing its position, size and age.
Hubble Telescope
To date, thanks to the Hubble telescope, it has been possible to detect the location of the galaxies closest to us, determine their sizes and determine the location relative to our world. Through the efforts of astronomers, mathematicians and astrophysicists, a map of the Universe has been compiled. Single galaxies have been identified, but for the most part, such large universal objects are grouped in groups of several dozen in a group. The average size galaxies in such a group are 1-3 million light years away. The group to which our Milky Way belongs contains 40 galaxies. In addition to groups, there are a huge number of dwarf galaxies in intergalactic space. As a rule, such formations are satellites of larger galaxies, such as our Milky Way, Triangulum or Andromeda.
Composition of the Universe
Steps towards exploring the Universe
A modern map of the Universe allows us not only to determine our location in space. Today, thanks to the availability of powerful radio telescopes and technical capabilities Hubble telescope, man was able not only to approximately calculate the number of galaxies in the Universe, but also to determine their types and varieties. Back in 1845, British astronomer William Parsons, using a telescope to study clouds of gas, was able to identify the spiral nature of the structure of galactic objects, focusing on the fact that different areas The brightness of star clusters can be greater or lesser.
A hundred years ago, the Milky Way was considered the only known galaxy, although the presence of other intergalactic objects was mathematically proven. Our space yard got its name back in ancient times. Ancient astronomers, looking at the myriads of stars in the night sky, noticed characteristic feature their locations. The main cluster of stars was concentrated along an imaginary line, reminiscent of a path of splashed milk. The Milky Way Galaxy and the celestial bodies of another well-known Andromeda galaxy are the very first universal objects from which the study of outer space began.
Star neighbors
Barred galaxies
Barred galaxies are much less common. They account for approximately half of all spiral galaxies. Unlike spiral formations, in such galaxies the origin comes from a bridge called a bar, arising from the two most bright stars, located in the center. A striking example Such formations are our Milky Way and the Large Magellanic Cloud galaxy. Previously, this formation was classified as irregular galaxies. The appearance of the jumper is on this moment one of the main areas of research in modern astrophysics. According to one version, a nearby black hole sucks and absorbs gas from neighboring stars.
The most beautiful galaxies in the Universe are the types of spiral and irregular galaxies. One of the most beautiful is the Whirlpool Galaxy, located in the celestial constellation Canes Venatici. IN in this case the center of the galaxy and the spirals rotating in the same direction are clearly visible. Irregular galaxies are chaotically located superclusters of stars that do not have a clear structure. A striking example of such a formation is the galaxy number NGC 4038, located in the constellation Raven. Here, along with huge gas clouds and nebulae, you can see a complete lack of order in the arrangement of space objects.
Whirlpool Galaxy
conclusions
You can study the Universe endlessly. Every time, with the advent of new technical means, a man lifts the curtain of space. Galaxies are the most incomprehensible objects in outer space for the human mind, both with psychological point vision, and looking back at science.
The outer space around us is not just lonely stars, planets, asteroids and comets sparkling in the night sky. Space is a huge system where everything is in close interaction with each other. Planets are grouped around stars, which in turn gather into a cluster or nebula. These formations can be represented by single luminaries, or they can number hundreds, thousands of stars, forming larger-scale universal formations - galaxies. Our star country, the Milky Way galaxy, is only a small part of the vast Universe, in which other galaxies also exist.
The universe is constantly in motion. Any object in space is part of a particular galaxy. Following the stars, galaxies also move, each of which has its own size, a specific place in the dense universal order and its own trajectory of movement.
What is the real structure of the Universe?
For a long time, humanity's scientific ideas about space were built around the planets of the solar system, stars and black holes that inhabit our stellar home - the Milky Way galaxy. Any other galactic object detected in space using telescopes was automatically included in the structure of our galactic space. Accordingly, there was no idea that the Milky Way is not the only universal formation.
Limited technical capabilities did not allow us to look further, beyond the Milky Way, where, according to conventional wisdom, the void begins. Only in 1920, the American astrophysicist Edwin Hubble was able to find evidence that the Universe is much larger and, along with our galaxy, there are other, large and small galaxies in this huge and endless world. There is no real boundary of the Universe. Some objects are located quite close to us, only a few million light years from Earth. Others, on the contrary, are located in the far corner of the Universe, being out of sight.
Almost a hundred years have passed and the number of galaxies today is already estimated at hundreds of thousands. Against this background, our Milky Way looks not at all so huge, if not quite tiny. Today, galaxies have already been discovered whose sizes are difficult even for mathematical analysis. For example, the largest galaxy in the Universe, IC 1101, has a diameter of 6 million light years and consists of more than 100 trillion stars. This galactic monster is located more than a billion light years from our planet.
The structure of such a huge formation, which is the Universe on a global scale, is represented by emptiness and interstellar formations - filaments. The latter, in turn, are divided into superclusters, intergalactic clusters and galactic groups. The smallest link of this huge mechanism is the galaxy, represented by numerous star clusters - arms and gas nebulae. It is assumed that the Universe is constantly expanding, thereby causing galaxies to move at tremendous speed in the direction from the center of the Universe to the periphery.
If we imagine that we are observing space from our Milky Way galaxy, which is supposedly located at the center of the universe, then a large-scale model of the structure of the Universe will look like this.
Dark matter - aka emptiness, superclusters, clusters of galaxies and nebulae - are all consequences of the Big Bang, which marked the beginning of the formation of the Universe. Over the course of a billion years, its structure undergoes a transformation, the shape of galaxies changes, as some stars disappear, swallowed up by black holes, while others, on the contrary, transform into supernovae, becoming new galactic objects. Billions of years ago, the arrangement of galaxies was completely different from what we see now. One way or another, against the background of constant astrophysical processes occurring in space, we can draw certain conclusions that our Universe does not have a constant structure. All space objects are in constant motion, changing their position, size and age.
To date, thanks to the Hubble telescope, it has been possible to detect the location of the galaxies closest to us, determine their sizes and determine the location relative to our world. Through the efforts of astronomers, mathematicians and astrophysicists, a map of the Universe has been compiled. Single galaxies have been identified, but for the most part, such large universal objects are grouped in groups of several dozen in a group. The average size of galaxies in such a group is 1-3 million light years. The group to which our Milky Way belongs contains 40 galaxies. In addition to groups, there are a huge number of dwarf galaxies in intergalactic space. As a rule, such formations are satellites of larger galaxies, such as our Milky Way, Triangulum or Andromeda.
Until recently, the dwarf galaxy “Segue 2”, located 35 kiloparsecs from our star, was considered the smallest galaxy in the Universe. However, in 2018, Japanese astrophysicists discovered an even smaller galaxy - Virgo I, which is a satellite of the Milky Way and is located at a distance of 280 thousand light years from Earth. However, scientists believe that this is not the limit. There is a high probability that galaxies of much more modest sizes exist.
After groups of galaxies come clusters, regions of outer space in which there are up to hundreds of galaxies various types, shapes and sizes. The clusters are colossal in size. As a rule, the diameter of such a universal formation is several megaparsecs.
A distinctive feature of the structure of the Universe is its weak variability. Despite the enormous speeds at which galaxies move in the Universe, they all remain part of one cluster. Here the principle of preserving the position of particles in space, which are affected by dark matter formed as a result of the big bang, operates. It is assumed that, under the influence of these voids filled with dark matter, clusters and groups of galaxies continue to move in the same direction for billions of years, neighboring each other.
The largest formations in the Universe are galactic superclusters, which unite groups of galaxies. The most famous supercluster is Great Wall Clown, an object of universal scale, stretching over 500 million light years. The thickness of this supercluster is 15 million light years.
IN current conditions spacecraft and technology do not allow us to consider the Universe to its full depth. We can only detect superclusters, clusters and groups. In addition, our space has giant voids, bubbles of dark matter.
Steps towards exploring the Universe
A modern map of the Universe allows us not only to determine our location in space. Today, thanks to the availability of powerful radio telescopes and the technical capabilities of the Hubble telescope, man has been able not only to approximately calculate the number of galaxies in the Universe, but also to determine their types and varieties. Back in 1845, British astronomer William Parsons, using a telescope to study clouds of gas, was able to reveal the spiral nature of the structure of galactic objects, focusing on the fact that in different areas the brightness of star clusters can be greater or lesser.
A hundred years ago, the Milky Way was considered the only known galaxy, although the presence of other intergalactic objects was mathematically proven. Our space yard got its name back in ancient times. Ancient astronomers, looking at the myriads of stars in the night sky, noticed a characteristic feature of their location. The main cluster of stars was concentrated along an imaginary line, reminiscent of a path of splashed milk. The Milky Way Galaxy and the celestial bodies of another well-known Andromeda galaxy are the very first universal objects from which the study of outer space began.
Our Milky Way has the complete set of all galactic objects that a normal galaxy should have. There are clusters and groups of stars here, total number of which there are approximately 250-400 billion. In our galaxy there are clouds of gas that form arms, there are black holes and solar systems similar to ours.
At the same time, the Milky Way, like Andromeda and Triangulum, are only a small part of the Universe, part of the local group of the Virgo supercluster. Our galaxy has the shape of a spiral, where the bulk of star clusters, gas clouds and other space objects move around the center. The diameter of the outer spiral is 100 thousand light years. The Milky Way is not a large galaxy by cosmic standards, its mass is 4.8 x 1011 Mʘ. Our Sun is also located in one of the arms of Orion Cygnus. The distance from our star to the center of the Milky Way is 26,000 ± 1,400 light years. years.
For a long time, it was believed that the Andromeda nebula, one of the most popular among astronomers, is part of our galaxy. Subsequent studies of this part of space provided irrefutable evidence that Andromeda is an independent galaxy, and much larger than the Milky Way. Images obtained using telescopes showed that Andromeda has its own core. There are also clusters of stars here and there are nebulae of their own, moving in a spiral. Each time, astronomers tried to look deeper and deeper into the Universe, exploring vast areas of outer space. The number of stars in this universal giant is estimated at 1 trillion.
Through the efforts of Edwin Hubble, it was possible to establish the approximate distance to Andromeda, which could not possibly be part of our galaxy. This was the first galaxy to be studied so closely. Subsequent years brought new discoveries in the field of exploration of intergalactic space. The part of the Milky Way galaxy in which ours is located has been studied more thoroughly. solar system. Since the middle of the 20th century, it has become clear that in addition to our Milky Way and the well-known Andromeda, there are a huge number of other formations on a universal scale in space. However, order required the ordering of outer space. While stars, planets and other cosmic objects could be classified, the situation with galaxies was more complicated. This was due to the enormous size of the areas of outer space under study, which were not only difficult to study visually, but also to evaluate at the level of human nature.
Types of galaxies in accordance with the accepted classification
Hubble was the first to take such a step, making an attempt in 1962 to logically classify the galaxies known at that time. Classification was carried out based on the shape of the objects under study. As a result, Hubble managed to arrange all the galaxies into four groups:
- the most common type are spiral galaxies;
- followed by elliptical spiral galaxies;
- with galaxy bar (bar);
- irregular galaxies.
It should be noted that our Milky Way is a typical spiral galaxy, but there is one “but”. Recently, the presence of a jumper - a bar, which is present in the central part of the formation - has been revealed. In other words, our galaxy does not originate from the galactic core, but flows out of the bridge.
Traditionally, a spiral galaxy looks like a disk-shaped spiral flat shape, in which there is necessarily a bright center - the core of the galaxy. There are most of these galaxies in the Universe and they are designated by the Latin letter S. In addition, there is a division of spiral galaxies into four subgroups - So, Sa, Sb and Sc. Small letters indicate the presence of a bright core, the absence of arms, or, conversely, the presence of dense arms covering the central part of the galaxy. In such arms there are clusters of stars, groups of stars that include our Solar System, and other space objects.
The main feature of this type is the slow rotation around the center. The Milky Way completes a revolution around its center every 250 million years. The spirals located closer to the center consist mainly of clusters of old stars. The center of our galaxy is a black hole, around which all the main movement occurs. Length of the route modern estimates is 1.5-25 thousand light years towards the center. During their existence, spiral galaxies can merge with other smaller universal formations. Evidence of such clashes in more early periods is the presence of haloes of stars and haloes of clusters. A similar theory underlies the theory of the formation of spiral galaxies, which were the result of the collision of two galaxies located in the neighborhood. The collision could not pass without leaving a trace, giving a general rotational impulse to the new formation. Next to spiral galaxy there is a dwarf galaxy, one, two or several at once, which are satellites of a larger formation.
Close in structure and composition to spiral galaxies are elliptical spiral galaxies. These are huge, the largest universal objects, including a large number of superclusters, clusters and groups of stars. In the largest galaxies, the number of stars exceeds tens of trillions. The main difference between such formations is their highly extended shape in space. The spirals are arranged in the shape of an ellipse. Elliptical spiral galaxy M87 is one of the largest in the Universe.
Barred galaxies are much less common. They account for approximately half of all spiral galaxies. Unlike spiral formations, such galaxies originate from a bridge called a bar, which flows from the two brightest stars located in the center. A striking example of such a formation is our Milky Way and the Large Magellanic Cloud galaxy. Previously, this formation was classified as irregular galaxies. The appearance of the jumper is currently one of the main areas of research in modern astrophysics. According to one version, a nearby black hole sucks and absorbs gas from neighboring stars.
The most beautiful galaxies in the Universe are the types of spiral and irregular galaxies. One of the most beautiful is the Whirlpool Galaxy, located in the celestial constellation Canes Venatici. In this case, the center of the galaxy and the spirals rotating in the same direction are clearly visible. Irregular galaxies are chaotically located superclusters of stars that do not have a clear structure. A striking example of such a formation is the galaxy number NGC 4038, located in the constellation Raven. Here, along with huge gas clouds and nebulae, you can see a complete lack of order in the arrangement of space objects.
conclusions
You can study the Universe endlessly. Every time, with the advent of new technical means, man lifts the veil of space. Galaxies are the most incomprehensible objects in outer space for the human mind, both from a psychological point of view and from a scientific perspective.
If you have any questions, leave them in the comments below the article. We or our visitors will be happy to answer them
Our Galaxy is just one of many, and no one knows how many there are in total. More than a billion have already been opened. Each of them contains many millions of stars. The most distant ones already known are located hundreds of millions of light years from earthlings, therefore, by studying them, we are peering into the most distant past. All galaxies are moving away from us and from each other, it seems that the Universe is still expanding and that scientists have not in vain come to the conclusion about big bang like its original.
In science, the word “Universe” has a special meaning. It refers to the largest volume of space, together with all the matter and radiation contained in it, that can affect us in any way. Earth Scientists can observe only one Universe, but no one denies the existence of others, just because our (far from perfect) instruments cannot detect them.
The Sun is one of billions of stars. There are stars much larger than the Sun (giants), and there are also smaller ones (dwarfs); the Sun is closer in its properties to dwarf stars than to giants. There are hot stars (they have a white-bluish color and a temperature of over 10,000 degrees on the surface, and some up to one hundred thousand degrees), there are cold stars (they are red, the surface temperature is about 3 thousand degrees). The stars are very far from us; it takes 4 years to fly to the nearest star at the speed of light (300,000 km/s), while you can fly to the Sun at that speed in 8 minutes.
Some stars form pairs, triplets (double, triple stars) and groups (open star clusters). There are also globular star clusters; they contain tens and hundreds of stars and are spherical in shape, with a concentration of stars towards the center. Open clusters contain young stars, while globular clusters are very ancient and contain old stars. There are planets near some stars. Whether there is life on them, much less civilization, has not yet been established. But they may well exist.
Stars form giant systems - Galaxies. The galaxy has a center (core), flat spiral arms in which most stars are concentrated, and a periphery, a voluminous cloud of rare stars. Stars move in space, they are born, live and die. Stars like the Sun live for about 10-15 billion years, and the Sun is a middle-aged star. So he still has a long way to go. Massive and hot stars “burn out” faster, and can explode as “supernovae” stars, leaving behind very small and super-dense formations - white dwarfs, neutron stars or “black holes”, in which the density of matter is so high that no particles can overcome the forces of gravity and escape from there. In addition to stars, the Galaxy contains clouds of cosmic dust and gas that form nebulae. The plane of the Galaxy, where maximum number stars, gas and dust, visible in the sky as the Milky Way.
There are many more millions of Galaxies, consisting of a huge number of stars. For example, the Magellanic Clouds, the Andromeda Nebula are other Galaxies. They are located at unimaginably large distances from us.
In our sky, the stars seem motionless, since they are very far from us, and their movement becomes noticeable only after tens and hundreds of thousands of years have passed.
Helpful information
Galaxy– a gravitationally bound system of stars, interstellar gas, dust and dark matter. All objects within galaxies participate in motion relative to a common center of mass. The word "galaxy" comes from the Greek name for our Galaxy. Core- an extremely small region in the center of the galaxy. When it comes to galactic nuclei, we most often talk about active galactic nuclei, where the processes cannot be explained by the properties of the stars concentrated in them. The photographs of galaxies show that there are few truly lonely galaxies. About 95% of galaxies form galaxy groups. If the average distance between galaxies is no more than an order of magnitude greater than their diameter, then the tidal influences of the galaxies become significant. These influences each component of the galaxy in different conditions responds differently. Milky Way, also called simply Galaxy, is a large barred spiral galaxy with a diameter of about 30 kiloparsecs and a thickness of 1000 light