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 human perception of the world, to realize the dimensions of what is happening and to imagine the structure of the Universe is quite difficult. 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 mathematical model space.
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 beautiful name The Milky Way, a few centuries ago, according to many scientists, was the center of the universe. In fact, it turned out that this is only part of the Universe, and there are other galaxies various kinds and sizes, big and small, some farther, 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 own solar system 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, celestial galactic objects that are in our field of view, make up 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. 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, others space bodies observed from the Earth are relatively young structural formations and our closest neighbors in 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 Big Dog small dwarf galaxies are located, the mass of which is 200-300 times less mass 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. Discovered in the lens of a telescope space nebulae, which over time counted more than a thousand, were most interesting objects in the Universe. 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 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 last quarter XX century, observations made using spacecraft and technology, including the famous Hubble telescope, confirmed these assumptions. Space is limitless, and our Milky Way is far from being the largest galaxy in the Universe, and besides, it is not its center.
Only with the advent of powerful technical means observation, the universe began to take on clear outlines. Scientists are faced with the fact that even such huge formations as galaxies can differ in their structure and structure, shape and size.
Through the efforts of Edwin Hubble, the world received a systematic classification of galaxies, dividing them into three types:
- spiral;
- elliptical;
- 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 space monsters do not have a clearly defined 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 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 a 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. From the Sun to the center of the galaxy, the path along modern estimates 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 with 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.
Most rare type are 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 filled with dark matter or clouds space 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. More than 55% of them total all universal objects. There are half as many elliptical galaxies - only 22% of 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 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 commonly referred to as 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, more large group galaxies. Earth, along with the Sun and milky way belongs to 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. Maybe, 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 space 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 remained before the fatal collision. earth years. 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 monsters huge size, hiding in dark matter and in the voids of space, will not be able to swallow the entire galaxy.
There are three main types of galaxies: spiral, elliptical, and irregular. The former include, for example, the Milky Way and Andromeda. In the center are objects and a black hole around which a halo of stars and dark matter revolve. Arms branch off from the core. The spiral shape is formed due to the fact that the galaxy does not stop rotating. Many representatives have only one sleeve, but some can count three or more.
Table of characteristics of the main types of galaxies
Spiral ones come with and without a jumper. In the first type, the center is crossed by a dense bar of stars. And the second such formation is not observed.
Elliptical galaxies are home to the oldest stars and do not have enough dust and gas to create young ones. They can resemble a circle, oval or spiral type in shape, but without sleeves.
Approximately a quarter of galaxies represent a group of irregular ones. They are smaller than spiral ones and sometimes display bizarre shapes. They can be explained by the appearance of new stars or by gravitational contact with a neighboring galaxy. Among the wrong ones are .
There are also many galactic subtypes: Seyfert (spirals with fast movement), bright elliptical supergiants (absorb others), ring (without a core), and others.
We have a magnificent observatory in the city. And I loved to disappear there in school years. The workers were loyal to me and fed my curiosity, shared the nuances of work and interesting astronomical facts. I remember that time with great fondness.
The emergence of galaxies
What is a galaxy? It's one of the fundamental concepts. I remember how they took me around the observatory museum and told me about it. What shortly after the Big Bang galaxies began to form as stars were born and gravitationally attracted to each other in sheets of gas caused by small fluctuations in the density of matter in the young universe. Then the stars began to form protogalaxies. It was very hard to imagine. But it felt like something unthinkable, grandiose.
In fact, now I understand what the galaxy is collection of stars and planets, great amount gas and dust that are held together by gravity. And all celestial bodies revolve around the central object. Just dry facts. And then it was practically magic.
How galaxies are classified
There, in the observatory, there were huge models various types galaxies. It turns out that most of the bright galaxies nearby are spiral. They differ in shape and size, interact with each other, sometimes crash into each other and merge, sometimes tearing each other apart. In general, all galaxies are divided into four main types:
-  spiral galaxies;
- galaxies with jumper;
- elliptical;
- irregular galaxies.
Spiral galaxy emerges when stars inside a protogalaxy are born With different intervals . The gas between developing stars is collapsing, and as a result, gravitational differences govern the stars, dust, and gas of the protogalaxy. This movement causes everything to rotate, and differences in gravity lead to the appearance of spiral arms.
When I look at the sky, I constantly mentally fly away to the stars and see in my imagination all this splendor. Stars gather into galaxies. Galaxies - into groups of galaxies, and these groups - into clusters.
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Many kids love Milky Way bars. And my grandson is no exception. Knowing the Basics of English language, he understands that milky means milky, and way means the way, the road. But recently he learned that the creators meant by this name not a trip along the roads with milk chocolate, but the name of our Galaxy "Milky Way". And then a hail of questions rained down:
- why our Galaxy called " Milky Way»?
- what Galaxy generally?
- if there is our Galaxy, so there are not ours galaxies?
I will try to answer these questions. I think that the answers may be useful to you in communicating with your children and grandchildren.
Origin of the name "Milky Way"
The beauty of the night sky, yourself celestial objects and phenomena have attracted the attention of people since time immemorial. But astronomical knowledge, which has taken shape in science, has come down to us from scientists Ancient Greece (Hellas). So, for example, the picture of the world Ptolemy dominated Europe for 14 centuries. But among the ancient Greeks themselves, ideas about the world around were intertwined with their religious beliefs and myths. Name "Milky Way" comes from Hellenic legends.
When the boy was born who was to become a mighty hero Hercules he was placed on the bed of the sleeping supreme goddess Hera for him to drink it breast milk and became immortal. But Hera woke up and pushed the mortal baby away, while her milk splashed across the sky, forming a whitish sparkling strip across the entire celestial sphere. So, according to the ideas of the Hellenes, "Milky (Milky) Way".
Our Galaxy
"Galaxy", translated from ancient Greek, means "Milky Way". Of course, in our time, no one would even think of believing in such an explanation for the appearance of this amazing object in our sky. So what is Galaxy in fact?
We understand that life on Earth can only exist thanks to the radiation of light and heat from a huge cosmic object called sun. This fire ball could contain 1,300,000 planets in volume, the size of the Earth. But he looks like soccer ball because it is very far from us. It turns out that all the stars in our sky are nothing but the same luminaries, somewhat different in temperature, size and age. It’s just that all of them are removed from us by colossal space distances, so they look like burning sparks.
Stars in the universe are not distributed randomly. They are collected by the forces of attraction into stellar associations, which, due to rotation, take the form of a disk thickened in the center. They are called galaxies. The star formation to which our Sun belongs is called "Milky Way". We see it from the side, which is why it sparkles with a whitish stripe across the sky. Almost all objects observed in the starry sky also enter our galaxy.
Other galaxies
Ferdinand Magellan used whitish nebulae in the 15th century for navigation in the Southern Hemisphere, later named Magellanic Clouds.
Another such luminous little cloud ( Andromeda's nebula) back in the 10th century, a Persian astronomer observed As-Sufi.
Only in the 19th century, scientists armed with sophisticated optical equipment were able to prove that these objects are located outside of our galaxies and, just like "Milky Way", are huge star clusters. These are the others closest to us, Galaxies. And there are billions of them.
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When I was in the 7th (!) grade, I argued with my desk mate about which is bigger: the galaxy or the universe. Now I am very ashamed of this argument. Thankfully, I've learned a lot more about the universe since then.
What is a galaxy
The galaxy is not a measure of the division of the universe, as some people (mostly children) mistakenly believe. It's just a collection of stars, gas, dust, dark matter, planets, held together. gravitational field and moving about the center of mass.
This is how not only planets and satellites move, but even the galaxy itself. Our galaxy is no exception, and we are now with great speed moving towards the center of the universe.
Some of the galaxies can be seen from our planet even without the help of a telescope. Unfortunately, there are only 4 of them:
- Andromeda (visible in the Northern Hemisphere);
- Large and Small Magellanic Clouds (these are 2 galaxies, visible in southern hemisphere);
- M33 in the constellation of the triangle (Northern Hemisphere).
It will be interesting to know that our galaxy is spiral, that is, it has arms, our solar system is located on the inner edge of one of them (Orion's arm), due to this location in the galaxy, we cannot see part of the arm through a telescope, for example .
What are groups of galaxies
In fact, there are very few lonely galaxies in the universe. About 96% are galactic associations. Very often in such clusters of galaxies there is one that is much larger than the others (dominant), and it is she who attracts the rest with her gravitational field. Over time, the largest galaxies absorb smaller ones, increasing their size.
Our galaxy is not alone either, it belongs to the local group of galaxies and dominates it along with Andromeda. The exact number of galaxies in our group is unknown, it is assumed that there are about 43 of them.
The dimensions of the universe itself are colossal, but it is also finite, there is absolutely nothing beyond 13.7 billion light years. But even the greatest minds of mankind find it difficult to answer the question of what this “nothing” is.
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I've been interested in astronomy for quite a long time, and I've studied everything! Films, books, pictures, articles, now it can be easily found, and I will try to answer your question here with the help of my knowledge. :) Space is fraught with many dangers and mysteries, and there is hardly a better place for us than the Earth. But let's take a look, shall we?
Our place in space
Everyone can well represent our home planet, if you rise higher into space, then there will be our solar system. It includes:
- 8 planets(they are all so different, beautiful and fraught with riddles that only, perhaps, have to be unraveled).
- main star- yellow dwarf Sun(do you know what it is huge body, containing 1352418 of our planets, is called yellow dwarf ? It turns out that there are stars much larger than our Sun!).
- well, where without stardust, meteorites and asteroids.
- we are surrounded Kuiper Belt- "remnants" from the formation of the solar system.
So...
We are leaving our solar system, but how many are around?! Can't count, billions planets, stars unimaginable in size clouds of gas, dust, energy... All this was formed due to the attraction to each other of this all by the forces gravity. All this (our galaxy) revolves around supermassive black hole. This object has not been studied at all, because according to modern concepts, a black hole is nothing does not radiate, but only "sucks" objects into itself, literally dissolving them.
But do not be afraid, we are far from it. The picture shows white patches- places with a lower temperature, but not all are clogged with planets and stars, there are dark areas- lots are empty.
Look at this photo:
Lots of lights, but it's really millions of galaxies, in our time, astronomers can observe them, but there are boundaries. The level of development of technology does not allow us to look further, we can only observe where we can look.
The dimensions of the visible part of the Universe are simply amazing! However, this is just a grain of sand on the shore of the boundless Ocean - Big Universe, - the true value of which we are not able to imagine or calculate ...
The Milky Way Galaxy is part of a family of neighboring galaxies known as the Local Group, and together with them forms a cluster of galaxies. Among nearby galaxies there are magnificent spirals. One of them, the Andromeda galaxy, is the most distant object visible naked eye. Most galaxies in the universe are either spiral or elliptical, and many of them are part of galaxy clusters.
Throughout the 19th century and at the beginning of the 20th century. astronomers did not know exactly what kind of hazy bright spots they saw through a telescope. It was clear that the stars are part of Milky Way as well as bright gas clouds like the Orion Nebula. But in their search for comets and planets, astronomers such as Charles Messier and William Herschel found thousands of fainter nebulae, many of which were spiral. Astronomers wanted to know if they were galaxies far beyond the Milky Way or just clouds of gas in our Galaxy. The answer to this question was possible only when a method was found to measure the distances to these faint nebulae.
In 1924, the American astronomer Edwin Hubble convincingly proved that spiral nebulae are giant galaxies, similar to the Milky Way, but infinitely distant from it. With a single blow, he opened up the staggering immensity of the universe. Hubble was the first to discover variable stars in the Andromeda galaxy - Cepheids. They were much fainter than the Cepheids of the Magellanic Clouds. The difference in brightness meant that the Andromeda galaxy must be 10 times further away from us than the Magellanic Clouds.
The Andromeda Galaxy can be observed with the naked eye - it is the most distant object that can be seen without binoculars or a telescope. Countless galaxies are much fainter than this one and, therefore, even more distant from us. Edwin Hubble discovered the realm of galaxies. Over the next few years, he measured the distances to many other spirals and was able to prove that even the nearest galaxies are distant from us by many millions of light years. The dimensions of the observable universe far exceeded previous guesses.
local group
Looking into deep space, we find that galaxies are not evenly distributed throughout the universe. Galaxies cluster together to form clusters, or families. Our own family is called the "Local Group". This is, in general, a rather sparse formation: about 25 of its members are scattered over a space of 3 million light years. The largest of them are the Milky Way, as well as the spiral galaxies M31 in Andromeda and the MZZ in Triangulum. The Milky Way is accompanied by about nine dwarf galaxies moving nearby, and Andromeda eight more. Astronomers keep finding new faint galaxies in our Local Group.
Each member of the "Local Group" moves under the influence of gravitational attraction all other members. All clusters of galaxies are held together by the gravitational field, which is the most important of the forces acting in the universe at large distances. By measuring the speeds of galaxies in the Local Group, astronomers can calculate its total mass. It is about 10 times larger than the mass of visible stars - hence it follows that the Local Group must contain a lot of dark, invisible matter.
Cluster in Virgo
If we continue our journey beyond the Local Group, we will encounter other small groups of galaxies - for example, Stefan's quintet, in which two spiral galaxies are entangled together. And then much larger clusters flicker. The huge Virgo cluster, about 50 million light-years away, is the nearest large cluster galaxies. It is too far away to be able to calculate the distance using variable stars. Instead, they use to calculate magnitudes most bright stars and maximum star clusters. Their brilliance is compared with the brilliance of similar objects, the distance to which is already known.
The Virgo Cluster is huge; it is spread over an area approximately 200 times the area occupied by the sky full moon! In that giant cluster has several thousand members. In its central part are three elliptical galaxies, first listed by Charles Messier: M84, M86 and M87. These are really huge galaxies. The largest of them, M87, is comparable in size to our entire "Local Group". The Virgo Cluster is so massive that its gravitational action not only holds this huge collective together, but also extends all the way to our "Local Group". Our Galaxy and its companions are slowly moving towards the Virgo Cluster.
Cluster in the constellation Coma Berenices
Moving even further, at a distance of about 350 million light years, we arrive at a huge galactic city in the constellation Coma Berenices. This is the Coma Cluster, containing over 1000 bright elliptical galaxies and possibly many thousands of smaller members that are no longer visible. in modern ways. The size of the cluster in diameter reaches 10 million light years; two supergiant elliptical galaxies are located in its very core. Astronomers suggest that this cluster contains tens of thousands of members.
All galaxies are held together by gravity. In this case, the velocities of the galaxies within the cluster indicate that only a few percent of the total mass is contained in the stars that we can see. The Coma Veronica cluster, like other large clusters of this type, is mostly composed of dark matter.
AT central regions densely populated clusters like the one in the Coma Berenices are unlikely to contain spiral galaxies. Perhaps this is because the spiral galaxies that once existed there merged together to form elliptical galaxies. Cluster of Veronica's Hair is a strong source x-ray radiation emitted by a very hot gas with a temperature of 10 to 100 million degrees. This gas is found in the central part of the cluster; in my own way chemical composition it is close to the material of stars.
It is possible that the following happened. The galaxies located in the central part of the cluster collided with each other and, scattering after the impact, shed their gas clouds. The gas was heated by friction as galaxies raced through it at speeds up to thousands of kilometers per second. As the galaxies lost their gas, their spiral arms gradually disappeared.
Superclusters and voids
Photographing deep space shows that as we move into the Universe, galaxies keep appearing and appearing. In almost every direction we look, there is a scattering of faint galaxies like dust. Some objects were found at a distance of up to 10 billion light years. Each of these countless galaxies contains billions of stars. Such numbers are hard to imagine even by professional astronomers. The extragalactic universe is larger than anything imaginable.
Almost all galaxies are in clusters containing from a few to many thousands of members. But what can be said about these clusters themselves: maybe they are also grouped into families? Yes, that's right!
The Local Cluster of Clusters, known as the "Local Supercluster", is a flattened formation that includes, among others, the Local Group and the Virgo Cluster. The center of mass is located in the Virgo cluster, and we are on the outskirts. Astronomers have made efforts to 3D map the Local Supercluster and reveal its structure. It turned out that it contains about 400 individual clusters galaxies; these clusters are collected in layers and bands separated by gaps.
Another supercluster is in the constellation Hercules. Before it, about 700 million light years, and for about 300 million light years on the way to it, galaxies, apparently, do not meet at all.
Thus, astronomers have established that superclusters are separated from each other by giant empty spaces. Inside superclusters there are also like "bubbles" millions of light years in size, which do not contain galaxies. Superclusters fold into threads and ribbons, giving the universe, on the grandest scale, a spongy structure.
Hubble's law and redshift
We now know that our universe is expanding all the time, getting bigger and bigger. Hubble played a decisive role in the discovery. Using Cepheid stars, he determined the distances to the nearest galaxies, and determined their velocities from redshift measurements. The discovery was made when he plotted the speeds of galaxies as a function of their distances. It turned out that the relationship of these two quantities is expressed on the graph by a straight line: the farther the galaxy is from us, the greater its speed. Hubble law States that the faster a galaxy moves, the more distant it is. Hubble found a relationship between two quantities that could be measured for nearby galaxies: between distance and redshift (which gives speed). And after such a connection is established, Hubble's law can be reversed and used for the reverse procedure. By measuring redshift for more distant galaxies, it is possible, using the Hubble law, to calculate the distance to them. This is how astronomers find out the distances to distant galaxies in our universe.
Of course, when using Hubble's law, there is some uncertainty about the correctness of the result. For example, if an inaccuracy is made in calculating the distances to the nearest galaxies, the graph will no longer be absolutely correct: any error in it will continue into deep space when we try to find out the distances to more distant galaxies using it. However, Hubble's law is the most important method studies of the large-scale structure of the universe.
Universe expansion
Why does Hubble's law imply that the universe is expanding? All galaxies are moving away from us. So the Milky Way is at the center of the universe? After all, when we see an explosion - for example, a firework exploded in the sky - then everything scatters in all directions from the place of the explosion. So, if everything around us is flying away from us, we must be in the center of this expansion?
No, it is not: we are not in the center.
When, during an explosion, individual parts fly apart into different sides, the distances between all fragments increase. This means that each piece "sees" how all the others fly away from it. To understand how this works, take Balloon hic and draw some galaxies on it using spiral and elliptical icons. Now slowly inflate the balloon. As it expands, the galaxies move away from each other. Whatever galaxy you choose as a starting point, all the others, as the balloon is inflated, are sprayed further and further.
This can also be discussed from a mathematical point of view. The shell of the ball is a curved surface, it has almost no thickness. When you inflate a balloon, this spherical surface, stretching, covers everything most space. The curved shell, being itself two-dimensional, expands into three-dimensional space. And as this happens, the galaxies drawn on the ball are moving further and further away from each other.
As for the Universe, the three dimensions of ordinary space are expanding in some special four-dimensional space, which is called space-time. An additional dimension is time. Over time, the three dimensions of the cosmos continuously increase their length. Clusters of galaxies, inextricably linked to expanding space, are constantly moving away from each other.
Age of the Universe
How can astronomers determine the age of the universe? We find out the age of a tree by counting the annual rings on the cut - one ring grows per year. Geologists can cordon off age rocks, settled in sediments, according to the fossils found in them. The age of the moon was determined by measuring the radioactivity of rocks containing radioactive elements. In all these methods, one way or another, they extract the necessary data - the number of rings, saw fossils, the intensity of the remaining radiation - and use them to calculate the age.
To determine the age of the expanding universe, we study the distance and velocities a large number galaxies. It turns out that for every million light-years away, the speed of galaxies increases by about 20 km / s (astronomers do not know this number quite accurately, with a tolerance of 2-3 km / s). Knowing how speed changes with distance, we can calculate that 17 billion years ago all matter was in the same place. This is one way to determine the age of the universe. Since her age is the time elapsed after big bang when the expansion started...
For more information about the real structure of the Universe, see the books of Academician N.V. Levashov "The Last Appeal to Mankind" and "Inhomogeneous Universe" and others.
800 trillion suns live in a distant cluster of galaxies
Ivan Terekhov, 10/17/2010
The infinite cosmos "throws" scientists more and more new, impressive details of existence at an early stage of its development. This time, astronomers from the Harvard-Smithsonian Center for Astrophysics, working with the SPT (South Pole Telecope), have discovered one of the most massive galaxy clusters, 7 billion light-years away from us. Information about total mass clusters can cause bouts of dizziness and nausea when trying to assess the extent of the action: according to measurements, a star cluster has a mass, equal to the mass 800 trillion suns.
The collection named SPT-CL J0546-5345, located in the constellation Pictorus. Its redshift z is 1.07, which means that astronomers are now observing the cluster in the state it was in seven billion years ago. Moreover, even then this structure was almost as large as the Coma Veronica cluster, which is one of the densest clusters, known to science. Researchers believe that over time SPT-CL J0546-5345 could have quadrupled.
“This cluster of galaxies wins the heavyweight title. This is one of the most massive clusters ever found at this distance," said Mark Brodwin of the center. (Mark Brodwin), one of the authors of an article published in "Astrophysical Journal". As Broadwin noted, SPT-CL J0546-5345 many fairly old galaxies. This means that the cluster arose in the "childhood" of the Universe, in the first two billion years of its existence. The age of the universe, according to the probe WMAP (Wilkinson Microwave Anisotropy Probe), is estimated at 13.73 billion years. Such clusters can be useful in studying the influence of dark matter and dark energy for the formation various structures in space.
The team discovered the cluster while working with the first data from the SPT telescope installed at the Amundsen-Scott station in Antarctica. The 10-meter telescope, operating in the 70-300 GHz frequency range, began operation in 2007. The search for galaxy clusters is its main task, with the help of SPT data, scientists hope to get closer to obtaining an equation of state for dark energy, which, according to astronomers, accounts for about 74% of the mass of the Universe. Found cluster astronomers studied with the help of tools space telescope Spitzer (Spitzer Space Telescope), as well as the group of telescopes of the Chilean observatory Las Campanas. This made it possible to single out individual galaxies in the cluster and estimate the speed of their movement.
SPT-CL J0546-5345 was able to detect, thanks to the so-called Sunyaev-Zeldovich effect - minor distortions in cosmic microwave background, "echoes" of the Big Bang, which occur when radiation passes through a large cluster. This search method equally well reveals both nearby and distant clusters, and also allows a fairly accurate estimate of their mass.
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» Galaxies and Universe
How to distinguish a comet without a tail from an ordinary nebula when observing?
The comet is moving relative to the stars. This movement can be noticed in a few hours or even in a few tens of minutes.
Which stars are the most in galaxies?
There are significantly more stars with low masses than stars with in large numbers. The bulk of low-mass stars are red dwarfs.
Why do old stars of spiral galaxies form a spherical subsystem, while young stars form a thin rotating disk?
The oldest stars in such galaxies occupy a region of space approximately the same as that occupied by the protogalactic cloud from which they formed. The remaining gas was prevented from shrinking in the galactic plane by centrifugal forces, throwing it away from the center. As a result, a thin rotating gaseous disk appeared in the plane of rotation of spiral galaxies, in which the youngest stellar objects of the galaxy are formed.
What is the oldest cosmic body that fell into the hands of man?
The age of one of the samples of lunar rock brought to Earth by the Apollo 15 expedition is estimated at 4 billion 150 million years.
What galaxies are visible to the naked eye?
One of these galaxies is our Milky Way galaxy. We view it from the inside, so it appears as a bright band in the night sky. The next galaxy is the famous Andromeda Nebula. It is visible to the naked eye as a luminous spot. In addition to these galaxies, the satellites of our galaxy, the Large and Small Magellanic Clouds, are clearly visible in the southern sky.
Why is there very little in the matter of the oldest stars in the galaxy? heavy elements, and in the substance of the youngest, on the contrary, their content is increased?
The oldest stars formed from a protogalactic gas cloud poor in heavy elements. massive stars, rapidly evolving, exploded and enriched the gas of the protogalaxy with heavy elements formed in them. Later generations of stars were formed from substances with a high content of metals.
What space objects resemble giant atomic nuclei? Can they be made up of protons?
Neutron stars are mostly made up of densely packed neutrons. In this state, a neutron star can be considered as a giant atomic nucleus. A cosmic body cannot consist of protons alone, since gigantic repulsive forces will arise between them and the body will collapse.
How can strong X-rays be produced on stars?
In double star system one of the components can be neutron star. The matter sucked in by this star accelerates to very high speeds in its vicinity. When a substance collides with a surface, energy is released in the form of X-rays. Such radiation can also arise in the collision of particles falling on a black hole.
What cosmic bodies cannot be separated, while their merger is possible?
Only black holes have these properties.
Where in space were formed the chemical elements that make up the human body?
The human body is 65% oxygen, 18% carbon, as well as nitrogen, magnesium, phosphorus and many other elements. In total, 70 chemical elements have been found in living organisms. All elements heavier than hydrogen and helium, including iron, were synthesized by thermonuclear reactions in the depths of the stars. Chemical elements, heavier than iron, formed during supernova explosions.
How to prove that the Sun is located and has always been close to the galactic plane?
Evidence that the Sun is close to the middle of the galactic disk is that the middle of the Milky Way almost coincides with the great circle celestial sphere. The velocity vector of the Sun relative to the center of the galaxy also lies in the galactic plane. This indicates that the Sun has always moved in this plane.
Does the expansion of the universe affect the Earth's distance:
1) to the moon;
2) to the center of the Milky Way;
3) to the galaxy M 31 in the constellation Andromeda;
4) to the center of the local supercluster of galaxies?
Cosmological expansion does not participate gravitationally related systems(Solar system, galaxy, clusters of galaxies). Therefore, in the first three cases, the cosmological expansion does not affect the distances between the Earth and the indicated objects, and in the last, fourth, it does.
Is it possible to see the past of the universe?
Anyone can do this by observing the starry sky. The farther away from us are stars or galaxies, the longer the light comes from them and the more distant past you can look into. For example, we see the closest star group to us, Alpha Centauri, as it was 4.3 years ago. And the Andromeda Nebula looks like it had 2.5 million years ago.
Why in various space objects almost the same relative abundance of helium, but different content heavier elements?
Is the stellar universe finite or infinite?
The boundary of the observable starry universe is located at a distance of about 13.4 billion light years from Earth. Such distance will pass light since the formation of the first stars. At more distant distances from us, stars have not yet been discovered.
