Geheimnisse der Milchstraße - Unsere Heimat im Universum

Have you heard that the Milky Way is not a pure spiral galaxy but a barred spiral galaxy or that in addition to Sagittarius a star, the black hole at the center of our Milky Way probably has another very massive black hole near its center but also Of these spectacular properties is the Galaxy as we also call the Milky Way, the home of human civilization and perhaps many other extraterrestrial cultures, it is the home of the planets of the solar system of the Sun and many other stars. ask ourselves a question: what mysteries does the Milky Way hide?

We already know a lot about ours. The galaxy has many interesting properties that have become interesting through centuries of sky observations. Today we want to look at the lesser known sides of the galaxy. , including the appearance of the galaxy around its suspected second black hole and the position of the Sun in the Milky Way. Some of you will, of course, be familiar with some of the topics, but these topics are presented less frequently in popular science. . today on a tour of the Milky Way, our galactic home, without which we would not exist, seen by man from the beginning, but only in 1609 by Galileo Galilei Recognized as a stellar island, the view of the galaxy unfortunately is no longer part of the daily experience of humanity.

Light pollution is too strong, especially in cities, so the Milky Way can only be seen in rural and less polluted areas. Its name comes from the ancient Greek word galaxies, which comes from the The word Gala comes from and means milk, while Xia translates as path. The Milky Way is a direct translation of the word galaxies, which is the corresponding ancient Greek term. So when we talk about galaxies in the universe, we mean direct translation. With the naked eye you can see many other milky ways in the sky, milky and bright stripes, in this strip you cannot see individual stars, but only some nebula-shaped fragments of their spiral arms and their center.

Look at the edge of the galaxy, in the south you can see the center of the Milky Way in the sky, be it our ancestors. First, we don't know the delicate band of the Milky Way or other more clearly visible galaxies like a dromeda with names. It was probably only our largest galactic neighbor and the dromeda that was discovered and consciously understood as an independent celestial object. This galaxy was still called a deity in ancient times, but then it was People are becoming more and more aware that Andromeda and other galaxies do not have to be planets but something completely different, which is why in Hubble's time it was still called Andromeda, for example, a spiral nebula, in the early 20th century was thought to be a structure within.

Our own galaxy, cables and other astronomers made the world realize that Andromeda, the Magellanic clouds and other spirals visible in the sky were independent islands of stars, while Aristotle claimed in his book Meteorologica that the Milky Way was a set of stars. On the one hand, the Persian astronomer Albioni recognized that countless stars come together to form the Milky Way, but only with the invention of the telescope Galileo was able to concretely demonstrate that the Milky Way is composed of myriads of unobserved stars and Emanuel Kant called it by speculation The Milky Way as a large body of rotating stars.

This view was more or less confirmed by the observation of William Herschel in 1785. He was the first to suggest the disc-flame-shaped Milky Way, but it was only 60 years after Irish astronomer Lord Ross recognized the difference between nebulae or galaxies with spiral and elliptical shapes, Dutch astronomer Jakobus-Kaptain observed the movement of stars in the night sky and said they were not random. observation, the Swede Bertilindblood and the Dutchman Jan Ort discovered that these moving stars are part of the rotation. In our galaxy we have to see that observing the Milky Way is not easy and centuries had to pass until we understood its true nature.

It is like someone who lives in the middle of a forest but cannot leave it and other forests only emerge from it. In the distance we see hundreds and thousands of trees around us, but it is difficult for us to recognize that it is just a forest like the others. forests that we see in the distance, but with the understanding that the Milky Way is a disk-shaped group around a common island. Although the center of gravity of the rotating stars has not yet been described, astronomers recognized that this was their own stellar island. They were able to describe its shape to a certain extent, but it was not clear to them what specific appearance the galaxy actually has: because Due to the absorption of visible light by interstellar dust, it is extremely difficult to obtain a holistic picture of the Milky Way through observations. , Edwin Hubble already recognized that galaxies have very different shapes, explained galaxies in his famous bifurcation of galaxies and discovered that, in addition to the elliptical galaxies known as e, there were two different types of islands of spiral stars, since spiral galaxies without bars contain a capital S and a lowercase letter after it, and once galaxies were discovered whose spiral arms were located in a kind of central bar, the question arose of what our Milky Way is like.

Now, for centuries, people only had data from observations in the optical range. In the electromagnetic spectrum, the universe is an incredibly huge place, so other areas of the spectrum also come into question, areas that we cannot see with our eyes but that we can make visible with special instruments such as telescopes. With the space telescope, observations were made in the infrared and ultraviolet spectrum. When examining the Milky Way, it was assumed that it was a pure spiral galaxy, however, through observations in other spectra the true appearance of the galaxy could be recognized and We were amazed.

The Milky Way had to be a barred spiral galaxy. We can imagine it as the galaxy ngc1300 in this one, which is a huge oval-shaped bar at the end of which the spiral arms begin. Particularly impressive in this composite image taken by Alma and the WLT are the dimensions of the spiral arms and their immensity. The shape of the Milky Way is probably similar. In its spiral arm, much of the star formation takes place, as can be seen here from In the numerous areas of star formation, which glow in reddish and violet tones, you can also see that the spiral arms do not pass completely, but rather They are repeatedly interrupted and started again, giving this galaxy a whirlpool-like structure and reinforcing the impression that all the stars, gas and dust in the spiral arm orbit around a common center NGC 1300 According to Hubble, we could identify the SBB or SBC type as a barred spiral galaxy.

This type of galaxy is very typical and NGC 1390 could be taken as a cousin galaxy. example of this class Another Hubble image allows us to see a different perspective of this galaxy is the stellar island in In the optical and ultraviolet range, the star-forming regions are less prominent here, but we see where there are more massive stars that emit a lot of radiation ultraviolet. Especially the bright places in the galaxy contain many bright, hot stars. What is especially surprising here is the bright center. To see where we find the highest density of stars, the mini spiral in the center of Star Island is also unique.

It almost seems as if there is a second, even smaller galaxy at the core of a larger one. It has not yet been proven whether our Milky Way has such a characteristic. ngc-1300 is 67 million light years away. of us, so it is not in the local group of each galaxy cluster like the Milky Way or the Andromeda Triangle, but is part of the so-called Aridan galaxy cluster of a collection of galaxies larger and even more massive than the ours, which in turn shares the same home as the local group, that is, the Virgo supercluster. This should be understood as a set of galaxy clusters.

Ultraviolet and infrared observations of the Milky Way are ultimately just an imprecise attempt to recognize the nature of the Milky Way and the shape it really has. We cannot know in detail, some scientists assume that it is an SBB USB-C type galaxy, while other researchers want to give it the appearance of a pure spiral galaxy without bars, but the truth is that it is unlikely that the Via Milky is an elliptical galaxy. Therefore, the galaxy is probably a barred spiral galaxy, but the bars are not its only properties. We cannot imagine our galactic home simply as a wide, flat island of stars; it is no secret that it also extends into a third dimension. thick, but we will see how far the Milky Way pushes it in the next chapter based on its streams of stars and their greetings.

Let's go back in time a little to look at the Milky Way, well, not just a little, but 13. billion years 800 million years after the Big Bang, enormous amounts of gas and stars accumulated in one place in the universe and began As this rotating mass accumulates for hundreds of millions of years, more and more matter spins, more stars are formed and the character of this cosmic vortex becomes recognizable. It must be a galaxy. To be more precise, it should be the Milky Way in front of us. We call this structure protocalaxy of the Milky Way, that is, the predecessor of the galaxy we know.

As we learned in the last chapter as a spiral bar, in some simulations you can see the exact process of galaxy formation. Gas and stars are directed from all directions towards a point and gather around it. Researchers suspect the cause is Sagittarius, a star. This vortex represents that the black hole must have formed before the formation of the proto-Milky Way and must have attracted a lot of material due to its high gravity. This assumption, of course, is not certain, but we can imagine that those enormous black hole holes arose from the initial chaos of the universe left by the Big Bang.

Before galaxies such as one formed, the star Sagittarius a was probably initially much smaller than today, but its gravity was apparently sufficient to accumulate material. was attracted, the gravitational potential of the entire structure, that is, of the entire galaxy, increased and more and more gas and stars arrived at it, the Milky Way Protogalaxy was formed quite early in the universe, only 800 million years After the Big Bang, after eventually reaching an impressive size, it subsequently had to join with other small galaxies and in parallel many other galaxies were formed that collided with each other and gave food to the young galaxy.

It was almost destroyed, but it stood its ground time and time again and somehow managed to overcome this galactic cataclysm. We are now moving 3 billion years into the future, to a time approximately 10 billion years ago that was probably an uncertain time the universe was still relatively young many galaxies had already formed the second generation of stars began to form sending its radiation to the universe, the Milky Way is still a fairly young stellar island and has already grown quite a bit. In this uncertain and less feared time there was a gigantic collision that significantly influenced the fate of the young Milky Way.

A large galaxy rushed towards the Milky Way and collided with it because this galaxy was large but less massive than the Milky Way. At that time our galaxy was the Luck of Dominion. A large factor in this collision and tearing of this galaxy Astronomers discovered a few years ago that the remains of this galaxy in the form of stars are found in the Hall or Milky Way. This large galaxy, which the scientific journal Nature describes as the companion galaxy of the Milky Way, turns into vultures in helmets named after Gaia, the personified goddess of the earth, and a zeladus, a giant, son of Gaia and Uranus, the sky.

Both names come from Greek mythology and are significant for the immensity and meaning of it. Surprisingly, it is not known that the Milky Way originated as a result of the collision of many small galaxies, as astronomers have long known, almost all galaxies in this universe were created through galactic cannibalism, that is, through the constant fusion of larger galaxies. and smaller stellar islands, but Geier's discovered collision in zillertos with the Milky Way shows that K million larger ones also exist. What is special about this collision? The Vulture in zillertos was not only incorporated by the Milky Way and the stars of this Galaxies that were once huge are now located in the Hall or Milky Way, no, it probably also gave the Milky Way its current flattened shape and that appearance. of its galactic disk, but how is the Geier star discovered in zillerdos and how can such a collision be reconstructed?

This was also the question of Amina Helmi, a professor of astronomy at the University of Groningen, who was specifically looking for such stars. Remains of other galaxies in our galaxy To find thistype of stars, he looked for those that had a similar chemical composition, that were positioned in a similar way, and that moved in a similar way. The scientist observed all of them in the halo of the Milky Way to learn their history. and how the collision could have occurred. Helmi played a key role in the development of the vulture satellite and within the framework of this project she examined a large number of stars.

After the latest data release from the Geyer mission, Helm became available with data on more than 1.7 billion stars. What you and your team found was surprising. A number of stars in the Milky Way that should not be underestimated seem to come from the already described collision with the Vultures in Zillertus, but not only that, but also the chemical composition. Most of these stars differ significantly from the native stars of the Milky Way and form a fairly homogeneous group. The stars in this galaxy are even younger than those in the human strait, so they are mainly found in the Halle or galaxy, parts of which can be described as less ancient: other parts of the galaxy, such as the galactic center, are under the spiral arms and goes even further than the precursor.

The disk of the Milky Way would form from this collision and could therefore take on its current appearance. Gai a zillertos made This disk became thicker and shook it appropriately during the collision. During the collision, Geyer would break up completely and its stars would be dragged towards the Milky Way or towards the halo that the Vulture distributes in counters of the stellar stream and chemically. Stars of different composition in Hall or in the Milky Way are not the only evidence of galactic collisions around the Milky Way: some streams of stars have been discovered that extend tens of thousands of light years into intergalactic space, we can also see them like remains of previous ones. or current galactic collision of the Milky Way with other galaxies understand that these star streams surround the galaxy in part as a ring are already being absorbed by it some of the star streams are probably more permanent than others in the star streams are likely that many comes from the so-called Sagittarius dwarf galaxy, a small dwarf galaxy approximately 70,000 light years from Earth and 50,000 light years from the core of the Milky Way.

It orbits our galactic home in a polar orbit. It spirals towards the Milky Way and has crossed the galactic plane several times in the past and as a result of this partial collision many stars were detached from the dwarf galaxy, some of them grouped in streams of stars around the Milky Way and others remained trapped in the galactic plane. In the future, astronomers expect that the Secretarius dwarf galaxy will eventually become just a huge stream of stars, which will then settle as a ring around the galaxy and will probably orbit it for many years. hundreds of millions of years until at some point it completely disappears in the galactic plane.

We know for sure that the Milky Way had a turbulent past with many mergers and culminations, but in all of these great events there was not only gas, dust and stars from other galaxies found a home in ours. Other galaxies must have become even more mysterious objects of interest to be able to find such a mysterious object or several such mysterious objects are now breaking into the center of the Milky Way to investigate its core. We know with a fair amount of certainty that there is a super water-rich black hole at the center of every galaxy, but before we talk about the sensational properties of Sagittarius asters, I want to explain the history of the discovery of the black aster.

We have already talked about the electromagnetic spectrum In addition to infrared and ultraviolet astronomy, there is another subarea that plays an important role, especially in celestial exploration from Earth: radio astronomy, which results from radio radiation in a very large subarea of ​​the spectrum. The image that can be seen here all the time is from this discovery the first image of the Milky Way black hole reaching supermass but from our guitarist we already have To represent a lot, as mentioned in the last chapter, the Milky Way has absorbed many other galaxies in its long past and includes some very large chunks like vultures.

In Zelatus, since we know that almost every galaxy comes with a very massive black hole, we may have to wonder if, in addition to the many streams of stars that the galaxy stole from other star islands or formed itself, there could be a second candidate for a supermassive black hole in our galaxy. The Milky Way also has many star clusters. They are essentially characterized by the fact that they represent a compact set of thousands or billions of stars in a very small space and come in two versions: open star clusters that, for example, can often be seen in the vicinity of gas clouds interstellar. or globular star clusters that have a spherical shape.

Star clusters are mainly found in the Milky Way and are its oldest components, while open star clusters are more recent in nature. The stars in Kugelsternhafen, by the way, are strongly gravitationally bound to each other, but we return to the center of the Milky Way within a radius of three. Around Solitarius Arstein there are no less than 6,000 stars, some of which have very elliptical orbits around the hole black. The one we are in has approximately one star every 3 light years, which means that in the galactic center there are 6,000 times more stars than in the area three light years in diameter around the Sun, one of these stars in the densely populated center has 62 18 billion kilometers on average from the ass of Sagittarius and many tens of heavy solar masses during its closest approach the star is at 6.7% of the speed of accelerated light.

In addition to such giant stars, we also have star clusters that measure up to 200 light years from the heart of the Milky Way. Together, all these clusters have a mass of more than a million suns. However, according to astronomers, one of these star clusters is said to host a black hole that, with 100,000 solar rays. This secondary black hole in the Milky Way, unlike the supermassive black holes of Gitarius, is only a star of a fraction of the mass of Sagittarius, but still heavy enough to hold together a large star cluster. star or the so-called stellar black holes: the latter arise exclusively from the death of enormous stars, when they collapse and create a black hole by means of a supernova or lightning.

These holes weigh only a few dozen solar masses, while interbarrier black holes are among the representatives of supermasses and reach several thousand. Intermediate black holes can weigh hundreds of thousands of solar masses and have long been suspected of being at the heart of star clusters. There does not appear to be any relationship between the size of these star clusters. and the massive richness of the black hole, while astronomers have yet to specifically detect this black hole weighing 100,000 solar masses: another team of researchers. Since they had already found a completely unexpected place, another star cluster in the center of the Milky Way is called. irs13e.

It is very close to the star Sagittarius and is only half a light year away from it, as observed by French astronomer Jean Pierre Maja of the Institute of Astrophysics with his team in Paris with the help of large telescopes in Mauenack in Hawaii. and in Chile the galactic center discovered at least 6 very bright and apparently extremely massive stars that travel together through space. Apparently these stars were held together by a massive central object and not Sagittarius Asters but by a small black hole. Maja and his colleagues published their results in the journal Astronomie und astrophysics and estimate that the black hole has a mass of 1,300 suns, which which is nothing compared to the more than 4 million solar masses of the lone star or the 100,000 solar masses of the second largest black hole, but it seems to be one of many intermediate representatives, its way of acting is conceivable that in the sanatorium a -stein, in addition to the extremes, there are dozens, if not hundreds or thousands, of intermediate black holes with their own stars orbiting them.

We know what gigantic forces the stars around an intermediate black hole have to withstand: they have to withstand both the gravity of their own black hole and that of the star Salitarius, so they are probably not to be envied while the center of the Galaxy is probably a difficult place not only for stars but also for life. Let's ask another question: what is the galactic disk? It has more secrets than one might think at first glance. Moving away from the center of the galaxy we reach its This is the most impressive part of any galaxy, because almost all the properties of a galaxy come together here: there are especially high-mass stars and low mass, with partially rich stars and consisting almost exclusively of hydrogen up to the metallic content of We will talk about stars later, when we look at the galactic habitable zone.

The galactic disk is not only in the shape of a disk and lies flat like a plate, because its simple appearance is deceiving, since it also has a very complex structure. The disk essentially consists of two parts with very different properties: the first is known as a thin disk and has a thickness of between 1,000 and 1,300 light years, its visible radius is approximately 50,000 light years, which should give the galaxy a diameter total of 100,000 to 120,000 light years because We are in a proverbial forest with billions of living trees, we can only guess the actual size of the forest or the Milky Way.

If we approach the galactic edge, the disk logically becomes less and less dense. However, the most distant stars are located more than 100,000 light years from the center of the galaxy and are therefore not located in the galaxy. The disk is made up almost exclusively of small, lower-mass stars that we can barely see, but which are revealed through their radiation, among others. Other things: The galactic disk contains about 80% of the mass of the entire galaxy and is the youngest part of it, but the less known fact is this: In the thin disk, there is a second disk that is located very close from the center.

This disc is approximately four times thicker than the thin disc. Although it is closer to the center, it is significantly less dense than the outer thin disk because it is composed mainly of older stars and has hardly any gas and dust, the thin disk, on the other hand, is full of gas. In it, next to the galactic center, are most of the star formation areas. Although the thick disk has a higher density of stars, it hardly has any gas, so the thinner disk with all the matter together is a little denser, but what really happens? Size of a galaxy Determining the size of a galaxy or even the size of the Milky Way is a complicated question because most star islands do not have clear boundaries, so they have a clear beginning. and a clear ending.

However, all larger galaxies, apart from the disk in question, have a central zone. An island star looks very different: some galaxies have expanding spiral arms, but others are more elliptical in shape and lack any concrete structure. In this sense, the structure of a galaxy can be compared to a city of stars, a stellar city that can be seen as a dispersed collection of stars and matter, rather than being seen as an object with a fixed structure and a beginning and A clearly defined ending, like A Real City, due to its numerous suburbs and widespread residential areas, it is difficult to tell where it begins and where it ends.

Of course, we can set arbitrary limits. In astronomy, the brightness and density of stars is often used to determine and define where they are. If a galaxy falls below a certain density of stars at a certain point, then by definition it is no longer a star city. However, even beyond this limit, a galaxy still has houses and buildings. , the Milky Way also has stars beyond its visible disk, at a distance of up to 100,000 light years from its center. Generally, in astronomy, the end of a galaxy is defined as the area in which the stellar density falls around a star 100 square light years.

If the density of stars exceeds this number, it breaks. From the so-called stellar diameter of galaxies, our Milky Way has a stellar diameter of about 100,000 to 120,000 light years, if you look at the thin disk. An additional fact, by the way, with a stellar diameter of approximately 200,000 light years. years, Andromeda is significantly larger than the Milky Way, but apparently has less mass since this galaxy is therefore the mass champion of the local group, but not the largest stellar island. The spiral arms of the galaxy are undoubtedly its outstanding features that give ourgalaxy a kind of structure and are the longest elements of a stellar island that form in the center pass through the thick disk and are almost invisible in the outer regions of the thin disk on the number of its spiral arms.

There has been much discussion within The scientific community is now assumed that the galaxy has four large spiral arms, but as to the exact appearance of the arms and how they are structured in detail is still a subject of research, it is believed that all four. The spiral arms begin at the center of the galaxy. However, there is one thing we should not expect: the galaxy does not have perfect spirals, the spiral arms of other galaxies branch off each other or twist unexpectedly. In general, they are very irregular in the Milky Way. The two largest arms of the Milky Way are the Perseus Arm and the Scooterus Arm, both of which begin at the end of the structure called the long bar in the galactic center.

This is also a fact that only a few people know about, in addition to the visible elongated bar: The center of the Milky Way contains another bar, called the galactic bar, from which hang two less pronounced arms, the Sagittarius arm and the Sagittarius arm. Sagittarius. Norma arm, both could easily be overlooked because they are so thin. By the way, the Sun is located in a lateral area of ​​the arm of Sagittarius in the so-called Orion Arm, this is formed next to another arm of the thin arm of Sagittarius and this meets the scooter arm. Apparently the thick arm influences the thin arm and divides it into two smaller arms at the intersection.

However, this is very lucky for the sun because like us, as you will see later, it is located in a much quieter area of ​​the Milky Way, while the Orion arm ends in front of the Perseus arm, the Sagittarius arm. It continues and ends about 45,000 light years from the center. Infrared studies showed that the well around Centauro's office is On average, about 30% more red giants have red giant arms; By the way, red giants are those stars that have already progressed a little further in their development and, for example, long ago left burning hydrogen behind. Our Sun will too.

One day it will be a red giant, but now we know our galaxy. In the past, many stars must have formed in the sputum of Taurus, which have now reached a very advanced stage of their development. We can imagine it in a similar way. Because of the arm of Perseus and because between them is the arm of Orion and, therefore, also the Earth. In the great spiral arm we can observe very well and know with great certainty that the Milky Way looks like a gigantic whirlpool. Further investigation revealed the following: the two large spiral arms contain mainly older stars, while the more numerous and thinner arms contain more young stars.

The Milky Way has gas and dust So there are two large spiral arms intertwined with old stars and some smaller ones are populated by young stars, hot stars It is possible that the stars in the thinner spirals migrate to the larger arms because they have a greater gravitational pull and, as we have already seen, the sun has one. I chose a cozy place in the middle of Orion at night, but what does this mean for the formation of planets and also life? In the last chapter of this documentation, join me on a journey to the arms of Orion and discover with me what the surroundings of the sun are like and why it is an ideal place for the formation of planets and also life. the galaxy our sun is literally the star of our solar system without it neither the planets nor life on earth would be imaginable it holds all the celestial bodies together in a balanced gravitational dance and fuses hydrogen into helium inside more than a dozen million degrees Celsius We have already talked on this channel about the special place that the Earth occupies in the solar system: it is in the middle of the habitable zone, which is characterized because liquid water and pleasant temperatures are possible for the development of life in the planet.

Life as we know it We cannot tell the evolution of extraterrestrial life. Although we could imagine organisms that require elements other than water, carbon or oxygen, we cannot prove their existence but we digress here. Let's go back to the solar system. Most natural scientists agree that, in addition to this habitable zone, other properties of a planet and a star are important for life to arise, such as, among others, a stable magnetic field, the recycling of material through tectonics of plates, an atmosphere that is not too dense and not too thin, a natural moon-shaped satellite and, above all, a silent and solid connection with a sun that shines too strongly or too weakly would be just as detrimental to the development of life like a star whose brightness is pleasant but which has too much activity.

For example, we saw in another video with red dwarfs that are not only too active but also keep their planets trapped in a synchronous rotation. One revolution of this planet corresponds to one revolution of its orbit, which means that a planet always shows the same face to its star. One side of the planet is then burned by radiation from its central body, the other side, however, dies first. By the way, we also "find this phenomenon on our moon or in the ice wounds of Jupiter or other gas giants in our solar system. These are many properties that a planet or a star must have.

In our stellar neighborhood, for example, we see many red spots. Dwarfs, which are also planets. According to current knowledge, they are probably less suitable places for the development of life. We also see many binary star systems. These are, by the way, the most common in the galaxy and form up to 50% of all star systems, if we use current criteria. To develop life we ​​would need a single star like the Sun, ideally a G-class star. These are celestial objects with a mass approximately that of the Sun or more According to Alpha Centauri A and B, Alpha Centauri A and B are good candidates for this type of star, but what properties should stars still have so that life can arise in their environment and even more fundamentally we have to ask how and where can life arise?

Planets arise on which this life finally exists, it all starts with the fact that the Milky Way and our Sun are very suitable for the development of life. Above all, our Sun has the right concentration of metals. Here we must be careful and not equate ourselves. Astronomers understand metals as all elements higher than hydrogen or helium. In the astronomical sense, carbon and nitrogen are also considered metal-rich elements. Oxygen, three essential elements for development. In the case of life, the metal content of a star is also called metallicity. The primordial gas cloud, that is, the interstellar gas structures that emerged from the Sun and other planets, apparently had exactly the right amount beyond the Sun.

The ideal place in the Milky Way is not necessarily the great spiral arm where gigantic old stars give it a deadline and the enormous supernova explodes, not even, as we have seen, directly in the arm of Orion but rather at its edge, that is, it escapes both the deadly radiation of the stellar explosions and the radiation that It disperses into space when young stars form. Having a star directly in the spiral arms is therefore quite detrimental to the development of life; The same applies to the galactic center far enough from the core of the Milky Way and we don't have to worry about too much gravity or radiation from gigantic black holes, the factors of high metallicity and the correct positioning of a star in its galaxy come together to form a region that is described in an essay by goyamo González González was an assistant professor at the University of Washington in 2001 and became an associate professor at Drive City College in 2007.

Analogous to the stable zone of a solar system, it understands The GHz As a region of the Milky Way in which Earth-like planets are found, it may contain liquid water on its surface and provide a long-term habitat for animal-type microbial life; However, the GHz depends on the so-called chemical evolution of a galaxy, which sounds boring at first but includes the next and very exciting development of our Milky Way - we have already heard that the core of the galaxy is rather an older part, It is also logical that it first moves matter towards the center of a stellar island during its formation, due, among other things, to supermassive black holes, which guarantee a high concentration of gas and stars in a protogalaxy, and the gas collapses in this region central. stars, almost all of which actually have no metallic quality, these initial stars must have been gigantic and only existed for a few million years or perhaps even a few hundred thousand years because these stars were so large that they had helium in their core and Hydrogen, the only elements that make it up, additional elements created through nuclear fusion, carbon, oxygen, nitrogen, iron, magnesium and other chemical elements were bred inside a custom-made star that was getting old.

These stellar giants exploded into spectacular supernovels that spawned the app As the elements spread across the galaxy, the elements spread a little further outward and stimulated additional interstellar gas clouds to collapse and form stars. However, these now-forming stellar images received an injection of metallicity from dead stars, richer in metals than those of the first generation. At the same time, the Milky Way became increasingly larger and more massive, gradually forming an extensive disk in which the development of the stars in the core was repeated. Gradually the galactic disk received more and more stars with a higher concentration of metals - this is called chemical.

In the evolution of a galaxy there were stars that barely had any metallicity, but then they exploded in gigantic supernovae, the remains of which formed into new stars that contained more metal. This generation of stars also died and their remains were in turn collected to form the new star of a third generation. This process began in the center of the Milky Way and continues outward into the galactic disk. After the stars there exploded in supernovae and distributed their metal-rich seeds throughout the galaxy, our sun also emerged from a nebula that was not only accompanied by a supernova but also by up to 8 explosions Our sun is a third generation star formed from many predecessor stars.

In addition to the elements so important for life, such as nitrogen, carbon and oxygen, many other materials are also necessary. Our star, for example, is made up of one-third iron and more than 30% oxygen, which is mainly found in the mantle and only a small part is freely available in the atmosphere. For planets similar to Earth, elements such as silicon, magnesium, sulfur or nickel are also important, which in addition to iron and oxygen form the concrete base. material for the terrestrial planets and, among other things, they are why they are also called geophysically important substances, because without them the development of terrestrial celestial bodies is inconceivable and without them we would literally have no soil under our feet.

It only constitutes a small part of our planet and contributes less to the structure of the planet than to the development of its biosphere. Most elements are made up of very heavy stars, especially iron, which can be seen as the end product of any process. Stellar fusion occurs after a very massive star fuses that element inside itself under enormous pressure and, if there are sufficient quantities, it can no longer produce anything else and collapses under its own weight in a supernova or lightning burst. gamma. One could probably expect many Earth-like or at least terrestrial planets in the Milky Way or, unfortunately, there are fewer good things to report on this front, since González and his colleagues discovered in 2001 that the concentration of iron and other important elements in the galaxy The disk is steadily shrinking as fewer and fewer massive stars produce their harvest in the form of geophysically important elements.

However, if a galaxy develops normally, no galaxy can sustain the formation of extremely massive stars for long. As a galaxy continues to exist, smaller, lower mass stars form. Although these have a high metallicity, a fourth generation of stars is expected to follow this star. This discovery is consistent with the fact that most of the Earth-like planets found by astronomers are already very old, so the Milky Way is in its wedding, planet formation is already behind it and the planet TheFormation in the galaxy has been on a downward trend for several billion years, which is only accelerating as the galaxy ages, and the possibility has probably never been as low in galactic history as it is currently.

The more the Milky Way develops, the more potentially habitable worlds are lost over time. The galactic habitable zone is based on criteria that scientists have created based on the image and position of the Earth or Sun in the galaxy. The same also applies to the habitable zone of a Stern planet. Two concepts are developed based on the model of life on Earth and do not say what life form could still exist in the galaxy. Perhaps there are many extraterrestrial civilizations hidden in the hello of the Milky Way that are based on completely different criteria than life.

On Earth, perhaps extraterrestrial life forms have evolved on planets in the center of the galaxy and can withstand the strong radiation there through mechanisms unknown to us. When we talk about habitable zones, we know absolutely nothing about other forms of life and ultimately can only watch. to what we know The journey takes us through the appearance of the Milky Way, its streams of stars and its halo until we reach the center. We discovered that the Milky Way is much more complex than we thought and that there are probably dozens of them. There are not hundreds of black holes at the center of the galaxy, although there is only one supermassive Sagittarius black hole astern, but the giant probably has at least one colleague weighing 100,000 solar masses in its vicinity.

The result of our observation of the galactic disk may have surprised. For some people, the Milky Way has two galactic disks, one thin and one thick, the four spiral arms, when pulling on these disks, meet the regions of the galactic hello, They branch from each other, form new arms or simply dissolve. That sin has achieved a privileged place among the spiral arms is thanks to chance, the correct metallicity of our star and its distance from the galactic center and, according to current knowledge, it is thanks to the dangerous large and small spiral arms that it developed life on Earth at all.

Many of you probably already knew some of the facts mentioned in this documentary. I have consciously pointed out the detailed treatment of star formation and nebulae or Foregoing the Eagle Nebula to show you some of the lesser known sides of the Milky Way, we can be grateful to have this place in our galaxy as our own and we should be truly grateful to have evolved from 4.5 billion years of planetary history and can now think about the place we call home. Way is and remains our eternal home and there is no telling how long it will continue to produce suitable stars and habitable planets.

Long live the galaxy and long live the study of astronomy, in this sense, all the best and see you soon.