Introductory lesson. Subject of astronomy. Subject of astronomy Structure and scale of the universe presentation 11
Part one ASTRONOMICAL ASPECT OF THE PROBLEM
1. The scale of the Universe and its structure If professional astronomers constantly and tangibly imagined the monstrous magnitude of cosmic distances and time intervals of the evolution of celestial bodies, it is unlikely that they could successfully develop the science to which they devoted their lives. The space-time scales familiar to us since childhood are so insignificant compared to cosmic ones that when it comes to consciousness, it literally takes your breath away. When dealing with any problem in space, an astronomer either solves a certain mathematical problem (this is most often done by specialists in celestial mechanics and theoretical astrophysicists), or improves instruments and observation methods, or builds in his imagination, consciously or unconsciously, some small model the space system under study. In this case, the main importance is a correct understanding of the relative sizes of the system being studied (for example, the ratio of the sizes of parts of a given space system, the ratio of the sizes of this system and others similar or dissimilar to it, etc.) and time intervals (for example, the ratio of the flow rate of a given process to the rate of occurrence of any other). The author of this book dealt quite a lot, for example, with the solar corona and the Galaxy. And they always seemed to him to be irregularly shaped spheroidal bodies of approximately the same size - something around 10 cm... Why 10 cm? This image arose subconsciously, simply because too often, while thinking about one or another issue of solar or galactic physics, the author drew the outlines of the objects of his thoughts in an ordinary notebook (in a box). I drew, trying to adhere to the scale of the phenomena. On one very interesting question, for example, it was possible to draw an interesting analogy between the solar corona and the Galaxy (or rather, the so-called “galactic corona”). Of course, the author of this book knew very well, so to speak, “intellectually,” that the dimensions of the galactic corona are hundreds of billions of times larger than the dimensions of the solar corona. But he calmly forgot about it. And if in a number of cases the large dimensions of the galactic corona acquired some fundamental significance (this also happened), this was taken into account formally and mathematically. And yet, visually, both “crowns” seemed equally small... If the author, in the process of this work, had indulged in philosophical reflections about the enormity of the size of the Galaxy, about the unimaginable rarefaction of the gas that makes up the galactic crown, about the insignificance of our little planet and our own existence and about other equally valid subjects, work on the problems of the solar and galactic coronas would stop automatically. .. May the reader forgive me this “lyrical digression”. I have no doubt that other astronomers had similar thoughts as they worked through their problems. It seems to me that sometimes it is useful to take a closer look at the “kitchen” of scientific work... If we want to discuss exciting questions about the possibility of intelligent life in the Universe on the pages of this book, then, first of all, we will need to get a correct idea of its spatio-temporal scale . Until relatively recently, the globe seemed huge to people. It took Magellan’s brave companions more than three years to make their first trip around the world 465 years ago, at the cost of incredible hardships. A little more than 100 years have passed since the time when the resourceful hero of Jules Verne’s science fiction novel, using the latest technological advances of the time, traveled around the world in 80 days. And only 26 years have passed since those memorable days for all mankind, when the first Soviet cosmonaut Gagarin circled the globe on the legendary Vostok spacecraft in 89 minutes. And people’s thoughts involuntarily turned to the vast expanses of space in which the small planet Earth was lost... Our Earth is one of the planets of the solar system. Compared to other planets, it is located quite close to the Sun, although it is not the closest. The average distance from the Sun to Pluto, the most distant planet in the solar system, is 40 times greater than the average distance from Earth to the Sun. It is currently unknown whether there are planets in the solar system that are even more distant from the Sun than Pluto. One can only say that if such planets exist, they are relatively small. Conventionally, the size of the Solar System can be taken to be 50-100 astronomical units *, or about 10 billion km. By our earthly scale, this is a very large value, approximately 1 million greater than the diameter of the Earth.Rice. 1. Planets of the Solar System
We can more clearly imagine the relative scale of the solar system as follows. Let the Sun be represented by a billiard ball with a diameter of 7 cm. Then the planet closest to the Sun - Mercury - is located on this scale at a distance of 280 cm. The Earth is at a distance of 760 cm, the giant planet Jupiter is at a distance of about 40 m, and the farthest planet - in many respects, Pluto is still mysterious - at a distance of about 300m. The dimensions of the globe on this scale are slightly more than 0.5 mm, the lunar diameter is slightly more than 0.1 mm, and the Moon’s orbit has a diameter of about 3 cm. Even the closest star to us, Proxima Centauri, is so far away from us that compared to it, interplanetary distances within the solar system seem like mere trifles. Readers, of course, know that a unit of length such as a kilometer is never used to measure interstellar distances**). This unit of measurement (as well as the centimeter, inch, etc.) arose from the needs of the practical activities of mankind on Earth. It is completely unsuitable for estimating cosmic distances that are too large compared to a kilometer. In popular literature, and sometimes in scientific literature, the “light year” is used as a unit of measurement to estimate interstellar and intergalactic distances. This is the distance that light, moving at a speed of 300 thousand km/s, travels in a year. It is easy to see that a light year is equal to 9.46 x 10 12 km, or about 10,000 billion km. In the scientific literature, a special unit called the “parsec” is usually used to measure interstellar and intergalactic distances;
1 parsec (pc) is equal to 3.26 light years. A parsec is defined as the distance from which the radius of the Earth's orbit is visible at an angle of 1 second. arcs. This is a very small angle. Suffice it to say that from this angle a one-kopeck coin is visible from a distance of 3 km.
Rice. 2. Globular cluster 47 Tucanae
None of the stars - the closest neighbors of the Solar System - are closer to us than 1 pc. For example, the mentioned Proxima Centauri is located at a distance of about 1.3 pc from us. On the scale in which we depicted the Solar System, this corresponds to 2 thousand km. All this well illustrates the great isolation of our Solar system from surrounding stellar systems; some of these systems may have many similarities with it. But the stars surrounding the Sun and the Sun itself constitute only an insignificant part of the gigantic group of stars and nebulae, which is called the “Galaxy”. We see this cluster of stars on clear moonless nights as a stripe of the Milky Way crossing the sky. The galaxy has a rather complex structure. In the first, roughest approximation, we can assume that the stars and nebulae of which it consists fill a volume shaped like a highly compressed ellipsoid of revolution. Often in popular literature the shape of the Galaxy is compared to a biconvex lens. In reality, everything is much more complicated, and the picture drawn is too rough. In fact, it turns out that different types of stars concentrate in completely different ways towards the center of the Galaxy and towards its “equatorial plane”. For example, gaseous nebulae, as well as very hot massive stars, are strongly concentrated towards the equatorial plane of the Galaxy (in the sky this plane corresponds to a large circle passing through the central parts of the Milky Way). At the same time, they do not show a significant concentration towards the galactic center. On the other hand, some types of stars and star clusters (the so-called “globular clusters”, Fig. 2) show almost no concentration towards the equatorial plane of the Galaxy, but are characterized by a huge concentration towards its center. Between these two extreme types of spatial distribution (which astronomers call "flat" and "spherical") are all the intermediate cases. However, it turns out that the bulk of the stars in the Galaxy are located in a giant disk, the diameter of which is about 100 thousand light years and the thickness is about 1500 light years. This disk contains slightly more than 150 billion stars of various types. Our Sun is one of these stars, located on the periphery of the Galaxy close to its equatorial plane (more precisely, “only” at a distance of about 30 light years - a value quite small compared to the thickness of the stellar disk). The distance from the Sun to the core of the Galaxy (or its center) is about 30 thousand km. light years. Stellar density in the Galaxy is very uneven. It is highest in the region of the galactic core, where, according to the latest data, it reaches 2 thousand stars per cubic parsec, which is almost 20 thousand times more than the average stellar density in the vicinity of the Sun ***. In addition, stars tend to form distinct groups or clusters. A good example of such a cluster is the Pleiades, which is visible in our winter sky (Figure 3). The Galaxy also contains structural details on a much larger scale. Research in recent years has proven that nebulae, as well as hot massive stars, are distributed along the branches of the spiral. The spiral structure is especially clearly visible in other star systems - galaxies (with a small letter, in contrast to our star system - Galaxies). One of these galaxies is shown in Fig. 4. Establishing the spiral structure of the Galaxy in which we ourselves find ourselves has proven extremely difficult.
Rice. 3. Photo of the Pleiades star cluster
Rice. 4. Spiral Galaxy NGC 5364
Stars and nebulae within the Galaxy move in quite complex ways. First of all, they participate in the rotation of the Galaxy around an axis perpendicular to its equatorial plane. This rotation is not the same as that of a solid body: different parts of the Galaxy have different periods of rotation. Thus, the Sun and the stars surrounding it in a huge area several hundred light years in size complete a full revolution in about 200 million years. Since the Sun, together with its family of planets, has apparently existed for about 5 billion years, during its evolution (from birth from a gas nebula to its current state) it has made approximately 25 revolutions around the axis of rotation of the Galaxy. We can say that the age of the Sun is only 25 “galactic years”; let’s face it, it’s a blooming age... The speed of movement of the Sun and its neighboring stars in their almost circular galactic orbits reaches 250 km/s ****. Superimposed on this regular motion around the galactic core are the chaotic, disorderly movements of stars. The speeds of such movements are much lower - about 10-50 km/s, and they are different for objects of different types. The speeds are lowest for hot massive stars (6-8 km/s); for solar-type stars they are about 20 km/s. The lower these velocities, the more “flat” the distribution of a given type of star is. On the scale that we used to visually represent the Solar System, the size of the Galaxy will be 60 million km - a value already quite close to the distance from the Earth to the Sun. From here it is clear that as we penetrate into increasingly more distant regions of the Universe, this scale is no longer suitable, since it loses clarity. Therefore, we will take a different scale. Let us mentally reduce the earth's orbit to the size of the innermost orbit of the hydrogen atom in the classical Bohr model. Let us recall that the radius of this orbit is 0.53x10 -8 cm. Then the nearest star will be at a distance of approximately 0.014 mm, the center of the Galaxy will be at a distance of about 10 cm, and the dimensions of our star system will be about 35 cm. The diameter of the Sun will have microscopic dimensions : 0.0046 A (angstrom unit of length equal to 10 -8 cm).
We have already emphasized that the stars are located at enormous distances from each other, and are thus practically isolated. In particular, this means that stars almost never collide with each other, although the motion of each of them is determined by the gravitational field created by all the stars in the Galaxy. If we consider the Galaxy as a certain region filled with gas, and the role of gas molecules and atoms is played by stars, then we must consider this gas to be extremely rarefied. In the solar vicinity, the average distance between stars is about 10 million times greater than the average diameter of stars. Meanwhile, under normal conditions in ordinary air, the average distance between molecules is only several tens of times greater than the size of the latter. To achieve the same degree of relative rarefaction, the air density would have to be reduced by at least 1018 times! Note, however, that in the central region of the Galaxy, where stellar density is relatively high, collisions between stars will occur from time to time. Here we should expect approximately one collision every million years, while in the “normal” regions of the Galaxy there have been virtually no collisions between stars in the entire history of the evolution of our stellar system, which is at least 10 billion years old (see Chapter 9). ).
We have briefly outlined the scale and most general structure of the star system to which our Sun belongs. At the same time, the methods with the help of which, over the course of many years, several generations of astronomers, step by step, recreated a majestic picture of the structure of the Galaxy, were not considered at all. Other books are devoted to this important problem, to which we refer interested readers (for example, B.A. Vorontsov-Velyaminov “Essays on the Universe”, Yu.N. Efremov “Into the Depths of the Universe”). Our task is to give only the most general picture of the structure and development of individual objects in the Universe. This picture is absolutely necessary for understanding this book.
Rice. 5. Andromeda Nebula with satellites
For several decades now, astronomers have been persistently studying other star systems that are more or less similar to ours. This area of research is called "extragalactic astronomy." She now plays almost the leading role in astronomy. Over the past three decades, extragalactic astronomy has made astonishing advances. Little by little, the grandiose contours of the Metagalaxy began to emerge, of which our stellar system is included as a small particle. We still don’t know everything about the Metagalaxy. The enormous remoteness of objects creates very specific difficulties, which are resolved by using the most powerful means of observation in combination with in-depth theoretical research. Yet the general structure of the Metagalaxy has largely become clear in recent years. We can define a Metagalaxy as a collection of star systems - galaxies moving in the vast spaces of the part of the Universe we observe. The galaxies closest to our star system are the famous Magellanic Clouds, clearly visible in the sky of the southern hemisphere as two large spots of approximately the same surface brightness as the Milky Way. The distance to the Magellanic Clouds is “only” about 200 thousand light years, which is quite comparable to the total extent of our Galaxy. Another galaxy “close” to us is the nebula in the constellation Andromeda. It is visible to the naked eye as a faint speck of light of 5th magnitude *****. In fact, this is a huge star world, in terms of the number of stars and total mass three times greater than our Galaxy, which in turn is a giant among galaxies. The distance to the Andromeda nebula, or, as astronomers call it, M 31 (this means that in the well-known catalog of Messier nebulae it is listed as No. 31), is about 1800 thousand light years, which is about 20 times the size of the Galaxy. The M 31 nebula has a clearly defined spiral structure and in many of its characteristics is very similar to our Galaxy. Next to it are its small ellipsoidal satellites (Fig. 5). In Fig. Figure 6 shows photographs of several galaxies relatively close to us. Noteworthy is the wide variety of their forms. Along with spiral systems (such galaxies are designated by the symbols Sа, Sb and Sс depending on the nature of the development of the spiral structure; if there is a “bridge” passing through the core (Fig. 6a), the letter B is placed after the letter S), there are spheroidal and ellipsoidal ones, devoid of any traces spiral structure, as well as “irregular” galaxies, a good example of which are the Magellanic Clouds. A huge number of galaxies are observed in large telescopes. If there are about 250 galaxies brighter than the visible 12th magnitude, then there are already about 50 thousand brighter than the 16th. The faintest objects that can be photographed at the limit by a reflecting telescope with a mirror diameter of 5 m are 24.5th magnitude. It turns out that among the billions of such faint objects, the majority are galaxies. Many of them are distant from us at distances that light travels over billions of years. This means that the light that caused the blackening of the plate was emitted by such a distant galaxy long before the Archean period of the geological history of the Earth!
Rice. 6a. Cross spiral galaxy
Rice. 6b. Galaxy NGC 4594
Rice. 6s. Galaxies Magellanic clouds
Sometimes among the galaxies you come across amazing objects, for example, “radio galaxies”. These are star systems that emit huge amounts of energy in the radio range. For some radio galaxies, the flux of radio emission is several times higher than the flux of optical radiation, although in the optical range their luminosity is very high - several times greater than the total luminosity of our Galaxy. Let us recall that the latter consists of the radiation of hundreds of billions of stars, many of which, in turn, radiate much stronger than the Sun. A classic example of such a radio galaxy is the famous object Cygnus A. In the optical range, these are two insignificant specks of light of the 17th magnitude (Fig. 7). In fact, their luminosity is very high, about 10 times greater than that of our Galaxy. This system seems weak because it is located at a huge distance from us - 600 million light years. However, the flux of radio emission from Cygnus A at meter waves is so great that it even exceeds the flux of radio emission from the Sun (during periods when there are no sunspots on the Sun). But the Sun is very close - the distance to it is “only” 8 light minutes; 600 million years - and 8 minutes! But radiation fluxes, as is known, are inversely proportional to the squares of the distances! The spectra of most galaxies resemble the sun; in both cases, individual dark absorption lines are observed against a fairly bright background. This is not unexpected, since the radiation of galaxies is the radiation of the billions of stars that comprise them, more or less similar to the Sun. Careful study of the spectra of galaxies many years ago led to a discovery of fundamental importance. The fact is that by the nature of the shift in the wavelength of any spectral line in relation to the laboratory standard, one can determine the speed of movement of the emitting source along the line of sight. In other words, it is possible to determine at what speed the source is approaching or moving away.
Rice. 7. Radio galaxy Cygnus A
If the light source approaches, the spectral lines shift towards shorter wavelengths; if it moves away, towards longer ones. This phenomenon is called the "Doppler effect". It turned out that galaxies (with the exception of a few closest to us) have spectral lines that are always shifted to the long-wavelength part of the spectrum (“red shift” of the lines), and the greater the distance the galaxy is from us, the greater the magnitude of this shift. This means that all galaxies are moving away from us, and the speed of “expansion” increases as the galaxies move away. It reaches enormous values. For example, the recession speed of the radio galaxy Cygnus A, found from the red shift, is close to 17 thousand km/s. Twenty-five years ago, the record belonged to the very faint (in optical rays of the 20th magnitude) radio galaxy 3S 295. In 1960, its spectrum was obtained. It turned out that the well-known ultraviolet spectral line belonging to ionized oxygen is shifted to the orange region of the spectrum! From here it is easy to find that the speed of removal of this amazing star system is 138 thousand km/s, or almost half the speed of light! Radio galaxy 3S 295 is distant from us at a distance that light travels in 5 billion years. Thus, astronomers studied the light that was emitted when the Sun and planets were formed, and maybe even “a little” earlier... Since then, even more distant objects have been discovered (Chapter 6). We will not touch upon the reasons for the expansion of a system consisting of a huge number of galaxies here. This complex question is the subject of modern cosmology. However, the very fact of the expansion of the Universe is of great importance for analyzing the development of life in it (Chapter 7). Superimposed on the overall expansion of the galaxy system are the erratic velocities of individual galaxies, typically several hundred kilometers per second. This is why the galaxies closest to us do not exhibit a systematic redshift. After all, the speeds of random (so-called “peculiar”) movements for these galaxies are greater than the regular redshift speed. The latter increases as the galaxies move away by approximately 50 km/s, for every million parsecs. Therefore, for galaxies whose distances do not exceed several million parsecs, the random velocities exceed the receding velocity due to the redshift. Among nearby galaxies, there are also those that are approaching us (for example, the Andromeda nebula M 31). Galaxies are not uniformly distributed in metagalactic space, i.e. with constant density. They show a pronounced tendency to form separate groups or clusters. In particular, a group of about 20 galaxies close to us (including our Galaxy) forms the so-called “local system”. In turn, the local system is part of a large cluster of galaxies, the center of which is in that part of the sky on which the Virgo constellation is projected. This cluster has several thousand members and is among the largest. In Fig. Figure 8 shows a photograph of the famous galaxy cluster in the constellation Corona Borealis, numbering hundreds of galaxies. In the space between clusters, the density of galaxies is tens of times less than inside the clusters.
Rice. 8. Cluster of galaxies in the constellation Corona Borealis
Noteworthy is the difference between clusters of stars that form galaxies and clusters of galaxies. In the first case, the distances between cluster members are enormous compared to the sizes of the stars, while the average distances between galaxies in galaxy clusters are only several times larger than the sizes of the galaxies. On the other hand, the number of galaxies in clusters cannot be compared with the number of stars in galaxies. If we consider a collection of galaxies as a kind of gas, where the role of molecules is played by individual galaxies, then we must consider this medium to be extremely viscous.
Table 1
|
Big Bang |
|
|
Formation of galaxies (z~10) |
|
|
Formation of the Solar System |
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|
Earth Education |
|
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The emergence of life on Earth |
|
|
Formation of the oldest rocks on Earth |
|
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The appearance of bacteria and blue-green algae |
|
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The emergence of photosynthesis |
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|
The first cells with a nucleus |
|
| Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday |
| The emergence of an oxygen atmosphere on Earth | Violent volcanic activity on Mars | |||||
| The first worms | Ocean plankton Trilobites | Ordovician The first fish | Silur Plants colonize land | |||
| Devonian The first insects Animals colonize land | The first amphibians and winged insects | Carbon The first trees The first reptiles | Permian The first dinosaurs | Beginning of the Mesozoic | Triassic First mammals | Yura The first birds |
| Chalk First flowers | Tertiary period First primates | First hominids | Quaternary period First People (~22:30) |
- * Astronomical unit - the average distance from the Earth to the Sun, equal to 149,600 thousand km.
- ** Perhaps, only the speeds of stars and planets in astronomy are expressed in units of “kilometers per second”.
- *** In the very center of the galactic core, in a region 1 pc across, there are apparently several million stars.
- **** It is useful to remember a simple rule: a speed of 1 pc in 1 million years is almost equal to a speed of 1 km/s. We leave it to the reader to verify this.
- ***** The flux of radiation from stars is measured by so-called “stellar magnitudes”. By definition, the flux from a star of the (i+1)th magnitude is 2.512 times less than from a star of the ith magnitude. Stars fainter than 6th magnitude are not visible to the naked eye. The brightest stars have a negative magnitude (for example, Sirius has a magnitude of -1.5).
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Lesson type: a lesson in studying and initially consolidating new knowledge.
Target: Forming an idea of the structure of the Universe and the place of planet Earth in the Universe.
Tasks: Educational: introduce students to cosmology, introduce non-systemic units of measurement used in cosmology, introduce the age and size of the Universe, introduce the concept of a galaxy, introduce the types of galaxies, form an idea of galaxy clusters, types of star clusters, the formation of nebulae in the Universe, introduce application of spectral analysis in cosmology, to form knowledge about the phenomenon of red shift of spectral lines in the spectra of galaxies, about the Doppler effect, about Hubble's law, to introduce the Big Bang Theory, to introduce the concept of critical density of matter.
During the classes
I. Organizational moment.
Slides 1-2
The objectives of the lesson are determined for the students, the course of the lesson and the final results of its implementation are highlighted.
II. Motivation for learning activities.
Knowledge of the structure and evolution of the Universe helps us understand the place of each of us in this world and the responsibility that lies with us for the preservation of life and our unique planet for future generations of people.
III. Updating knowledge.
Frontal survey
- What is the name of the star closest to planet Earth? (Sun)
- How many planets are there in the solar system? (Eight)
- What are the names of the planets in the solar system? (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune)
- What place does planet Earth occupy in the solar system in terms of distance from the Sun? (Planet Earth is the third planet from the Sun)
IV. Presentation of new material.
Slides 3-5. Cosmology. Non-system units of measurement. Age and size of the Universe.
“The Universe is a concept in astronomy and philosophy that does not have a strict definition. It is divided into two fundamentally different entities: speculative (philosophical) and material, accessible to observation at the present time or in the foreseeable future. Following tradition, the first is called the Universe, and the second is called the astronomical Universe, or Metagalaxy.” Today we will get acquainted with the structure of the astronomical Universe. And we will determine the place of our planet Earth in the Universe. “The universe is the subject of cosmology.”
The distances and masses of objects in the Universe are very large. Cosmology uses non-systemic units of measurement. 1 light year(1 light year) – the distance that light travels in 1 year in a vacuum – 9.5 * 10 15 m; 1 astronomical unit(1 AU) – average distance from the Earth to the Sun (average radius of the Earth’s orbit) – 1.5 * 10 11 m; 1 parsec(1 pc) - the distance from which the average radius of the earth’s orbit (equal to 1 AU), perpendicular to the line of sight, is visible at an angle of one arc second (1") - 3 * 10 16 m; 1 solar mass(1 M o) – 2 * 10 30 kg.
Scientists have determined the age and size of the Universe. Age of the Universe t=1.3 * 10 10 years. Radius of the Universe R=1.3 * 10 10 light l.
Slides 6-19. Galaxies. Types of galaxies. Clusters of galaxies.
At the beginning of the twentieth century, it became obvious that almost all visible matter in the Universe is concentrated in giant star-gas islands with a characteristic size of several kpc. These “islands” became known as galaxies.
Galaxies- These are large star systems in which stars are connected to each other by gravitational forces. There are galaxies containing trillions of stars. “This group of galaxies is called Stefan's Quintet. However, only four galaxies from this group, located three hundred million light years away, participate in the cosmic dance, moving closer and further away from each other. It's quite easy to find extra ones. The four interacting galaxies have yellowish colors and curved loops and tails, shaped by destructive tidal gravitational forces. The bluish galaxy, located in the picture at the top left, is much closer than the others, only 40 million light years away.”
There are different types of galaxies: elliptical, spiral and irregular.
Elliptical galaxies make up approximately 25% of the total number of high-luminosity galaxies.
Elliptical galaxies have the appearance of circles or ellipses, the brightness gradually decreases from the center to the periphery, they do not rotate, they have little gas and dust, M 10 13 M o. Before you is the elliptical galaxy M87 in the constellation Virgo.
Spiral galaxies resemble two plates or a lenticular lens placed together in appearance. They contain both a halo and a massive stellar disk. The central part of the disk, which is visible as a bulge, is called a bulge. The dark stripe running along the disk is an opaque layer of the interstellar medium, interstellar dust. The flat disc-shaped shape is explained by rotation. There is a hypothesis that during the formation of a galaxy, centrifugal forces prevent the compression of the protogalactic cloud in the direction perpendicular to the rotation axis. The gas is concentrated in a certain plane - this is how the disks of galaxies were formed.
Spiral galaxies consist of a core and several spiral arms or branches, the branches extending directly from the core. Spiral galaxies rotate, they have a lot of gas and dust, M 10 12 M?
“The American aerospace agency NASA has opened its own account on Instagram, where they post photographs of views of the Earth and other parts of the Universe. Stunning photographs from the Hubble Telescope, NASA's most famous Great Observatory, reveal things never before seen by the human eye. Never-before-seen distant galaxies and nebulae, dying and born stars amaze the imagination with their diversity, pushing one to dream of distant travels. Fabulous landscapes of star dust and gas clouds reveal mysterious phenomena of stunning beauty.” Here is one of the most beautiful spiral galaxies in the constellation Coma Berenices.
In the 20s In the 20th century, it became clear: spiral nebulae are huge star systems similar to our Galaxy and millions of light years away from it. In 1924, Hubble and Ritchie resolved the spiral arms of the Andromeda and Triangulum nebulae into stars. It was found that these “extragalactic nebulae” are several times farther from us than the diameter of the Milky Way system. These systems began to be called galaxies by analogy with ours. “The medium-sized galaxy M33 is also called the Triangulum galaxy after the constellation in which it is located. It is approximately 4 times smaller in radius than our Milky Way galaxy and the Andromeda galaxy. M33 is located close to the Milky Way and is clearly visible with good binoculars.”
“The Andromeda Galaxy is the closest giant galaxy to our Milky Way. Most likely, our galaxy looks about the same as this one. The hundreds of billions of stars that make up the Andromeda Galaxy together produce a visible, diffuse glow. The individual stars in the image are actually stars in our Galaxy, located much closer to the distant object.”
“When observing the starry sky far from large cities, on a moonless night a wide luminous stripe is clearly visible - the Milky Way. The Milky Way stretches like a silver stripe across both hemispheres, closing into a ring of stars. Observations have established that all the stars form a huge star system (galaxy).” The galaxy contains two main subsystems, nested one within the other: the halo (its stars are concentrated towards the center of the galaxy) and the stellar disk (“two plates folded at the edges”). “The solar system is part of the Milky Way galaxy. We are inside a galaxy, so it is difficult for us to imagine its appearance, but there are many other similar galaxies in the Universe and from them we can judge our Milky Way.” The Milky Way Galaxy consists of a core located at the center of the galaxy and three spiral arms.
“Studies of the distribution of stars, gas and dust have shown that our Milky Way galaxy is a flat system with a spiral structure.” The size of our galaxy is enormous. The diameter of the galaxy's disk is about 30 pc (100,000 light years); thickness - about 1,000 sv. l.
There are about 100 billion stars in our galaxy. The average distance between stars in the galaxy is about 5 light years. years. The center of the galaxy is located in the constellation Sagittarius. “Astronomers are currently carefully studying the center of our galaxy. Observations of the movement of individual stars near the center of the galaxy showed that there, in a small area with dimensions comparable to the size of the Solar system, invisible matter is concentrated, the mass of which exceeds the mass of the Sun by 2 million times. This indicates the existence of a massive black hole at the center of the galaxy.” The Milky Way Galaxy revolves around the center of the galaxy. The Sun makes one revolution around the center of the galaxy in 200 million years.
Examples of irregular galaxies are the Large Magellanic Cloud and the Small Magellanic Cloud - the closest galaxies to us, visible to the naked eye in the southern hemisphere of the sky, near the Milky Way. These two galaxies are satellites of our galaxy.
Irregular galaxies have no clearly defined core, no rotational symmetry, and about half of the matter in them is interstellar gas. When studying the sky using telescopes, many galaxies of irregular, ragged shape, similar to the Magellanic Clouds, were discovered.
“Violent processes occur in the cores of some galaxies; such galaxies are called active galaxies. In the M87 galaxy in the constellation Virgo, an ejection of matter is observed at a speed of 3000 km/s, the mass of this ejection is This galaxy turned out to be a powerful source of radio emission. Quasars are an even more powerful source of radio emission. Quasars are also powerful sources of infrared, x-ray and gamma rays. But the sizes of quasars turned out to be small, about 1 AU. Quasars are not stars; These are bright and highly active galactic nuclei located billions of light years away from Earth.” “At the center of the quasar there is a supermassive black hole that sucks in matter - stars, gas and dust. Falling onto a black hole, matter forms a huge disk, in which it heats up to gigantic temperatures due to friction and tidal forces.” “Perhaps one of the most detailed photographs of a quasar to date was published on the Hubble website. This is one of the most famous quasars, 3C 273, which is located in the constellation Virgo.” It became the first discovered object of its kind; it was discovered by astronomer Alan Sandage in the early 1960s. “Quasar 3C 273 is the brightest and one of the closest quasars: its distance is approximately 2 billion light years, and its brightness allows it to be seen in an amateur telescope.”
Galaxies are rarely solitary. 90% of galaxies are concentrated in clusters, which contain from tens to several thousand members. The average diameter of a galaxy cluster is 5 Mpc, the average number of galaxies in a cluster is 130. “The Local Group of galaxies, whose size is 1.5 Mpc, includes our Galaxy, the Andromeda Galaxy M31, the Triangulum Galaxy M33, the Large Magellanic Cloud (LMC), the Small Magellanic Cloud (MMO) - a total of 35 galaxies connected by mutual gravity. The galaxies of the Local Group are connected by common gravity and move around a common center of mass in the constellation Virgo.”
Slides 21-23. Star clusters.
Every third star in the galaxy is double, and there are systems of three or more stars. More complex objects are also known - star clusters.
Open star clusters occur near the galactic plane. In front of you is the Pleiades star cluster. The blue haze accompanying the Pleiades is scattered dust reflecting the light of the stars.
Globular clusters are the oldest formations in our Galaxy, their age is from 10 to 15 billion years and is comparable to the age of the Universe. The poor chemical composition and elongated orbits in which they move in the Galaxy indicate that globular clusters formed during the formation of the Galaxy itself. Globular clusters stand out against the stellar background due to their significant number of stars and clear spherical shape. The diameter of globular clusters ranges from 20 to 100 pc. M= 104 106 M?
Slides 24-29. Interstellar matter. Nebulae.
In addition to stars, cosmic rays (protons, electrons, and atomic nuclei of chemical elements), which move at speeds close to the speed of light, galaxies contain gas and dust. Gas and dust in the galaxy are distributed very unevenly. In addition to sparse dust clouds, dense dark clouds of dust are observed. When these dense clouds are illuminated by bright stars, they reflect their light, and then we see nebulae.
“The Hubble team releases a stunning photo every year to celebrate the anniversary of the space telescope's launch on April 24, 1990. In 2013, they presented to the world a photograph of the famous Horsehead Nebula, which is located in the constellation Orion, 1,500 light years from Earth.”
“The bright Lagoon Nebula contains many different astronomical objects. Particularly interesting objects include a bright open star cluster and several active star forming regions."
“The colorful Trifid Nebula allows us to explore cosmic contrasts. Also known as M20, it lies about 5,000 light-years away in the nebula-rich constellation Sagittarius. The size of the nebula is about 40 light years. l."
“It is not yet known what lights up this nebula. Particularly puzzling is the bright, inverted V-shaped arc that outlines the top edge of the mountain-like clouds of interstellar dust near the center of the image. This ghost-like nebula includes a small star-forming region filled with dark dust. It was first spotted in infrared images taken by the IRAS satellite in 1983. Shown here is a remarkable image taken by the Hubble Space Telescope. Although it shows many new details, the cause of the bright, clear arc could not be determined.”
The total mass of dust is only 0.03% of the total mass of the galaxy. Its total luminosity is 30% of the luminosity of stars and completely determines the emission of the galaxy in the infrared range. Dust temperature 15-25 K.
Slides 30-33. Application of spectral analysis. Redshift. Doppler effect. Hubble's law.
The light of galaxies represents the combined light of billions of stars and gas. To study the physical properties of galaxies, astronomers use spectral analysis methods . Spectral analysis– a physical method for the qualitative and quantitative determination of the atomic and molecular composition of a substance, based on the study of its spectrum. Astronomers use spectral analysis to determine the chemical composition of objects and their speed of movement.
In 1912, Slipher, an American astronomer, discovered a shift of lines towards the red end in the spectra of distant galaxies. “This phenomenon was called redshift. In this case, the ratio of the shift of the spectral line to the wavelength turned out to be the same for all lines in the spectrum of a given galaxy. Attitude 
, where is the wavelength of the spectral line observed in the laboratory, characterizes the red shift.”
“The currently generally accepted interpretation of this phenomenon is related to the Doppler effect. The shift of spectral lines to the red end of the spectrum is caused by the movement (removal) of the emitting object (galaxy) at a speed v in the direction from the observer. At low redshifts (z), the speed of the galaxy can be found using the Doppler formula: 
, where c is the speed of light in vacuum.”
In 1929, Hubble determined that the entire system of galaxies was expanding. “From the spectra of galaxies it has been established that they are “scattering” from us at a speed v, proportional to the distance to the galaxy:
v= H·r, where H = 2.4 * 10 -18 s -1 is the Hubble constant, r is the distance to the galaxy (m).”
Slides 34-38. The Big Bang Theory. Critical density of matter.
The theory of the expanding Universe has emerged, according to which our Universe arose from a super-dense state during a grandiose explosion and its expansion continues in our time. About 13 billion years ago, all the matter of the Metagalaxy was concentrated in a small volume. The density of the substance was very high. This state of matter was called “singular”. Expansion as a result of the “explosion” (“pop”) led to a decrease in the density of the substance. Galaxies and stars began to form.
There is a critical value for the density of a substance, on which the nature of its movement depends. The critical value of the substance density kr is calculated by the formula:
where H = 2.4 * 10 -18 s -1 – Hubble constant, G = 6.67 * 10 -11 (N * m 2)/kg 2 – gravitational constant. Substituting the numerical values, we get kr = 10 -26 kg/m 3. At< кр - расширение Вселенной. При >kr - compression of the Universe. The average density of matter in the Universe = 3 * 10 -28 kg/m 3.
Man always strives to understand the world around him. The study of the Universe has just begun. Much remains to be learned. Humanity is only at the very beginning of the journey of studying the Universe and its mysteries. “By presenting the Universe as the entire surrounding world, we immediately make it unique and unique. And at the same time, we deprive ourselves of the opportunity to describe it in terms of classical mechanics: because of its uniqueness, the Universe cannot interact with anything, it is a system of systems, and therefore in its relation such concepts as mass, shape, size lose their meaning. Instead, we have to resort to the language of thermodynamics, using concepts such as density, pressure, temperature, chemical composition.”
For more detailed information about this, you can use the following sources:
1). Physics. 11th grade: educational. for general education Institutions: basic and profile. levels / G.Ya. Myakishev, B.B. Bukhovtsev, V.M. Chagurin; edited by IN AND. Nikolaeva, N.A. Parfentyeva. - 19th ed. – M.: Education, 2010. – 399 p., l. ill. – (Classical course). – ISBN 978-5-09-022777-3.;
4). http://www.adme.ru
The address of our home in the Universe: Universe, Local Group of Galaxies, Milky Way Galaxy, Solar System, Planet Earth - the third planet from the Sun.
We love our planet and will always protect it!
V. Primary consolidation of knowledge.
Frontal survey
- What is the name of the science that studies the structure and evolution of the Universe? (Cosmology)
- What extra-system units of measurement are used in cosmology? (light year, astronomical unit, parsec, solar mass)
- What distance is called a light year? (Distance that light travels in one year)
VI. Independent work.
Students are asked to independently solve the problem: Average density of matter in the Universe = 3 * 10 -28 kg/m 3 . Calculate the critical value of matter density and compare it with the average matter density in the Universe. Analyze the result obtained and draw a conclusion about whether the Universe is expanding or contracting.
VII. Reflection.
Students are invited to evaluate the work of the teacher and their own work in the lesson by drawing positive or negative emoticons on pieces of paper issued by the teacher.
VIII. Homework.
Paragraphs 124, 125, 126. Answer questions orally on pages 369, 373.
Literature:
- Physics. 11th grade: educational. for general education Institutions: basic and profile. levels / G.Ya. Myakishev, B.B. Bukhovtsev, V.M. Chagurin; edited by IN AND. Nikolaeva, N.A. Parfentyeva. - 19th ed. – M.: Education, 2010. – 399 p., l. ill. – (Classical course). – ISBN 978-5-09-022777-3.
- http://ru.wikipedia.org
- http://www.adme.ru
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Astronomy is the science of celestial bodies (from the ancient Greek words aston - star and nomos - law). It studies visible and actual movements and the laws that determine these movements, shape, size, mass and surface relief, the nature and physical state of celestial bodies, interaction and their evolution.
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Exploring the Universe The number of stars in the galaxy is in the trillions. The most numerous stars are dwarfs with masses about 10 times less than the Sun. In addition to single stars and their satellites (planets), the Galaxy includes double and multiple stars, as well as groups of stars bound by gravity and moving in space as a single whole, called star clusters. Some of them can be found in the sky through a telescope, and sometimes even with the naked eye. Such clusters do not have a regular shape; more than a thousand of them are currently known. Star clusters are divided into open and globular. Unlike open star clusters, which consist primarily of main sequence stars, globular clusters contain red and yellow giants and supergiants. Sky surveys carried out by X-ray telescopes mounted on special artificial Earth satellites led to the discovery of X-ray emissions from many globular clusters.
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Structure of the Galaxy The overwhelming majority of stars and diffuse matter in the Galaxy occupies a lens-shaped volume. The Sun is located at a distance of about 10,000 Pc from the center of the Galaxy, hidden from us by clouds of interstellar dust. At the center of the Galaxy there is a nucleus, which has recently been carefully studied in the infrared, radio and X-ray wavelengths. Opaque clouds of dust obscure the core from us, preventing visual and conventional photographic observations of this most interesting object in the Galaxy. If we could look at the galactic disk from above, we would find huge spiral arms, mostly containing the hottest and brightest stars, as well as massive clouds of gas. The disk with spiral branches forms the basis of the flat subsystem of the Galaxy. And objects that concentrate towards the Galactic core and only partially penetrate into the disk belong to the spherical subsystem. This is a simplified form of the structure of the Galaxy.
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Types of galaxies 1 Spiral. This is 30% of galaxies. They come in two types. Normal and crossed. 2 Elliptical. Most galaxies are believed to have the shape of an oblate sphere. Among them there are spherical and almost flat. The largest known elliptical galaxy is M87 in the constellation Virgo. 3 Not correct. Many galaxies have a ragged shape without a clearly defined outline. These include Our Local Group's Magellanic Cloud.
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The Sun The Sun is the center of our planetary system, its main element, without which there would be neither the Earth nor life on it. People have been observing the star since ancient times. Since then, our knowledge of the luminary has expanded significantly, enriched with numerous information about the movement, internal structure and nature of this cosmic object. Moreover, the study of the Sun makes a huge contribution to the understanding of the structure of the Universe as a whole, especially those of its elements that are similar in essence and principles of “work”.
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The Sun The Sun is an object that has existed, by human standards, for a very long time. Its formation began approximately 5 billion years ago. At that time, in place of the solar system there was a vast molecular cloud. Under the influence of gravitational forces, vortices began to appear in it, similar to earthly tornadoes. In the center of one of them, the substance (mostly hydrogen) began to become denser, and 4.5 billion years ago a young star appeared here, which after a long period of time received the name Sun. Planets gradually began to form around it - our corner of the Universe began to take on the appearance familiar to modern humans. -
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The yellow dwarf Sun is not a unique object. It is classified as a yellow dwarf, a relatively small main sequence star. The “service life” allotted to such bodies is approximately 10 billion years. By space standards, this is quite a bit. Now our luminary, one might say, is in the prime of his life: not yet old, no longer young - there is still half his life ahead.
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Light Year A light year is the distance that light travels in one year. The International Astronomical Union has given its explanation of the light year - this is the distance that light travels in a vacuum, without the participation of gravity, in a Julian year. The Julian year is equal to 365 days. It is this decoding that is used in scientific literature. If we take professional literature, then the distance is calculated in parsecs or kilo- and megaparsecs. Until 1984, a light year was the distance that light travels in one tropical year. The new definition differs from the old one by only 0.002%. There is no particular difference between the definitions. There are specific numbers that determine the distance of light hours, minutes, days, etc. A light year is equal to 9,460,800,000,000 km, a month is 788,333 million km, a week is 197,083 million km, a day is 26,277 million km, an hour is 1,094 million km, a minute is about 18 million km., second - about 300 thousand km.
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Galaxy Constellation Virgo Virgo can be best seen in early spring, namely in March - April, when it moves to the southern part of the horizon. Due to the fact that the constellation has an impressive size, the Sun is in it for more than a month - from September 16 to October 30. On ancient star atlases, Virgo was represented as a girl with an ear of wheat in her right hand. However, not everyone is able to discern just such an image in a chaotic scattering of stars. However, finding the Virgo constellation in the sky is not that difficult. It contains a star of the first magnitude, thanks to the bright light of which Virgo can be easily found among other constellations.
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Andromeda Nebula The closest large galaxy to the Milky Way. Contains approximately 1 trillion stars, which is 2.5-5 times larger than the Milky Way. It is located in the constellation Andromeda and is distant from Earth at a distance of 2.52 million light years. years. The plane of the galaxy is inclined to the line of sight at an angle of 15°, its apparent size is 3.2 × 1.0°, its apparent magnitude is +3.4m.
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Milky Way The Milky Way is a spiral galaxy. Moreover, it has a bridge in the form of a huge star system, interconnected by gravitational forces. The Milky Way is believed to have existed for over thirteen billion years. This is the period during which about 400 billion constellations and stars, over a thousand huge gas nebulae, clusters and clouds were formed in this Galaxy. The shape of the Milky Way is clearly visible on the map of the Universe. Upon examination, it becomes clear that this cluster of stars is a disk whose diameter is 100 thousand light years (one such light year is ten trillion kilometers). The thickness of the star cluster is 15 thousand, and the depth is about 8 thousand light years. How much does the Milky Way weigh? It is not possible to calculate this (determining its mass is a very difficult task). Difficulties arise in determining the mass of dark matter, which does not interact with electromagnetic radiation. This is why astronomers cannot definitively answer this question. But there are rough calculations according to which the weight of the Galaxy ranges from 500 to 3000 billion solar masses
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Scales of the Universe:. V.A. Samodurov (PRAO AKC FIAN. Distances and sizes of Mass Times. Distances. We are used to not thinking about the size of our Universe.... Distances are a march!. We are used to not thinking about the size of our Universe... Shall we take a walk or a trip through it?
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V.A. Samodurov (PRAO AKC FIAN Distances and sizes of Masses Times
We are used to not thinking about the size of our Universe...
We are used to not thinking about the size of our Universe... Shall we take a walk or a trip through it? Our fastest supersonic passenger planes fly at a speed of approximately 2000 kilometers per hour, the speed of a regular car is 100 kilometers per hour, and a pedestrian is 5 kilometers per hour. How long would it take us to travel even in the immediate vicinity of the Universe? – The Moon’s orbit is 385,000 km. from the earth. Traveling by plane would take 8 days by plane, 160 days by car, and 9 years by foot! However, light travels this distance in just 1.3 seconds. – The Sun is at a distance of 149,664,900 kilometers. And now – even by plane it takes us 8 and a half years to get to the Sun, by car – 170 years, and on foot – more than 3 thousand years! However, light travels this distance in 500 seconds - 8 minutes and 20 seconds! The nearest star, Proxima Centauri, is located at a distance of 4.3 light years. That is, a beam of light travels from there at a speed of 300 thousand km sec for more than 4 years. – by plane – more than 2 million years, – by car – 46 million years, – on foot – more than 900 million years! During the entire existence of the Universe, we would have walked only about 60 sv. years! But to its visible edge - 13.7 billion light. years…
Let's imagine the Sun as a ball 1 meter in size (up to a person's waist). Then on this scale: - Earth - 100 meters from it, about the size of a small cherry (8 mm), - Jupiter, the size of a large orange (about 10 cm), will be at a distance of 500 meters. – Pluto will be about 4 km away. – the nearest star Proxima Centauri on this scale will be 25 thousand km from the Sun. A bit much, let's zoom out!
Let's imagine the Sun is the size of a billiard ball (7 cm). Then on this scale: – Mercury will be 2 m 80 cm away from it, – Earth: 7 m 60 cm (its size is 0.64 mm - like a poppy seed), the Moon will be 0.1 mm with an orbital diameter of 3 cm, – Pluto will be at a distance of about 30 meters . – the nearest star Proxima Centauri on this scale will be 2000 km from the Sun. – the size of the Galaxy will be 60,000,000 km. Again - too much! Even if you make the Sun the size of 1 pixel on an LCD monitor, to immediately see Proxima Centauri, you will need a monitor with a diagonal of about 8 kilometers.
Next - to better imagine the size of the Galaxy and the Universe as a whole - we again reduce the scale, the size of the Earth's orbit to the orbit of an electron in a hydrogen atom (0.53 * 10-8 cm). Then the nearest star will be at a distance of 0.014 mm from the Sun. And the diameter of the Sun itself – 0.0046 angstrom. The size of the Galaxy will be about 35 cm, and from the Sun to the black hole in the center 10 cm (just a stone's throw!). That is, by changing the scale, you can easily imagine everything speculatively; at the last scale, the size of the Universe (13.7 billion light years) is not so large, only 47 km 950 m.
Macroworld - let logarithms help us... The dimensions of the Universe are about 30 billion light years, or in meters - 3 × 1026. The dimensions of the smallest elementary particle are estimated by physicists at 10-16 m. Neutrinos - up to 10-24 m. “Planck length” 10-35 m The total number of atoms in our body is about 1028, and the total number of elementary particles (protons, neutrons and electrons) in the observable part of the Universe - approximately 1080. If the Universe were densely packed with neutrons, so that there was no empty space left anywhere in it, then it would contain only 10128 particles
Units The dimensions of the Universe are about 30 billion light years, or in meters - 3x1026. Therefore, astronomers use their own units of distance. 1″ Earth-Sun distance = 1 astronomical unit (AU or, in English: a.u.) Last month, without further fanfare, the International Astronomical Union (IAU) at the XXVIII General Assembly held in Beijing (China) transformed the unit by secret vote into a fixed one, defining it once and (we hope) forever as 149,597,870,700 meters. 1 parsec But: the nearest star is more than 300 thousand AU! Maybe we can measure the distance to the stars in light years? 1 St. g. ≈ 86400 × 365.25 × 300,000 km = 9,467,280,000,000 km ≈ 9.5 trillion km But, it is more logical to start from the astronomical unit. 1 parsec (Pc, in English Pc notation) = distance from which 1 AU. visible at an angle of 1″ Then – from 1 kPc (kiloparsec) the radius of the Earth’s orbit is 0.001″, from MPc10-6″, from the visible edge of the Universe megaparsec 4 × 10-9″ 1 pc = 205982 AU. = 30,814,526,974,157 km = 3.25 St. of the year
Universe The dimensions of the Universe are about 30 billion light years, or in meters - 3 × 1026. Let's summarize it into one map, and then look at it more closely. The main picture shows a “pocket map of the Universe”. Next, in six pictures, the map is cut into equal parts. One of the axes represents the distance from the center of the Earth. On the one hand, the distance is given in units of the radius of our planet. On the other hand, in more familiar units: on a pocket map these are megaparsecs, on six separate sheets the scale changes for convenience (kilometers, astronomical units, parsecs, megaparsecs).
Universe On the first sheet we see the Earth and its immediate surroundings. The main divisions of the internal structure of the Earth are shown. Above the surface we see many points - these are artificial satellites. The points are not randomly plotted; these are real data at the time of the full moon on August 12, 2003. The ISS and the Space Telescope are highlighted separately. A band of GPS satellites and geostationary satellites are visible. Above is the Moon and the WMAP satellite.
Universe The second sheet shows the Solar System. The asteroid belt is represented by two concentrations. This is due to the fact that only those small planets that are near the celestial equator are depicted. Because The plane of the ecliptic is inclined towards the equator, then we see two clumps near 12 and 24 hours. At the very top the boundary of the heliopause and the satellites approaching it are conventionally shown. Kuiper belt objects are also shown. Comet Halley is highlighted separately.
Universe The third sheet is the most boring. Empty from Pluto to the nearest stars. Only the Oort cloud.... And even then, we have only indirect information about it. But you can see how far away it is from the stars. Even flying from planet to planet within our system, we look at the stars as unattainable (yet) luminaries.
Universe Here they are - the stars! The stars of the Hipparcos satellite catalog that fall in the equatorial zone are shown, as well as some famous luminaries, clusters and nebulae. We can also build three-dimensional maps for nearby stars - anyone capable of three-dimensional vision can see how they are located in space relative to the Sun
Universe We are approaching the border of our Galaxy (it is shown by a dotted line, since we are greatly shifted from the center, the border, of course, is asymmetrical). Notable objects are shown inside the Galaxy: a double radio pulsar, a black hole candidate Cyg X-1, and the globular cluster M13. The center of the Galaxy is also highlighted. At the top we see the galaxies of the Local Group: the Andromeda Nebula and all the little things. In the upper right corner is M81. This is a more distant galaxy.
Cosmology, the world of galaxies. At the very bottom is our Virgo cluster (on the right, where M87 is). Distant objects formed as if two pillars. This is due to the fact that in the plane of the Milky Way the absorption of light is too great, and therefore we see distant galaxies and quasars only outside the plane of our Galaxy. Due to the fact that the map is conformal, the details of the large-scale structure are adequately conveyed. The old "Great Wall" and the "Sloan Great Wall" are visible - more distant and longer. Since real objects are plotted, at large distances the picture becomes incomplete - we see only the brightest sources (quasars of the Sloan Digital Survey, for example). Below is the large-scale structure of the Universe in three dimensions. Distances in pictures, 6th map of the Universe
Universe On the right are some clusters of galaxies in our sky. At the top is a cluster in the confluence. Virgo. Below is the large-scale structure of the Universe in three dimensions.
What is small in the Universe Stars Solar system Solar
What is small in the Universe
Repetition: Next - to better imagine the size of the Galaxy and the Universe as a whole - again - to the smallest scale: - the size of the Earth's orbit to the orbit of an electron in a hydrogen atom (0.53 * 10-8 cm). – the diameter of the Sun is 0.0046 angstroms. Then the nearest star will be at a distance of 0.014 mm from the Sun. The size of the Galaxy will be about 35 cm, and from the Sun to the black hole in the center 10 cm (just a stone's throw!). On this scale, the size of the Universe (13.7 billion light years) is not so large, only 47 km 950 m. Visual model: http://htwins.net/scale2/index.html
Repetition: The scale interval of sizes of objects in the Universe (from the fundamental length of M. Planck - 10–35 m to the limit of the visible part of the Universe of the Metagalaxy - 1027 m), located on the scale, and its scale center
The entire mass of the observable Universe is 1056 g; superclusters of galaxies (according to Vaucouleurs) - 1052 g; giant clusters of galaxies that are part of a supercluster - ...1048. The average mass of an individual galaxy is now estimated to be... 1044 g. As giant dust clouds with a mass on the order of 1040 g, star clusters have an average mass of the order of 1036 g. stars, despite their stunning diversity, are still concentrated in mass in the range of 1032 g The idea of planets is more vague, since, unfortunately, we know only one family of planets. But if we discard the extreme values (Jupiter and Pluto) and take the average value, then such an authorized representative will be Uranus 8.8 * 1028 g. The satellites of the planets have a mass of about 1024 g. Asteroids on their distribution diagram are in the range of 1020 g for large and 1016 -- for small ones. …….. Although there are still icy rings of Saturn with the most common diameter of 0.6 meters and, therefore, with a mass order of 10-4 g. But it is even more surprising that at the other end of the world scale in the microcosm the exponents obey the same pattern . The mass of an electron is 9.1 * 10-28 g, the mass of a proton and neutron is 1.6 * 10-24. And even the rest mass of a neutrino, according to preliminary results, is of the order of magnitude 10-32 grams.
Carl Sagan, a famous American scientist, compiled a “cosmic calendar” that has become extremely popular. He placed the entire history of the Universe, including the development of life on Earth, on the scale of a conventional cosmic year. Moreover, the history of human civilization itself covers almost one moment of such a calendar - hundredths seconds. Here's how it looks on three tables: Table 1 Pre-December dates Big Bang - January 1 The emergence of the Milky Way galaxy - May 1 The emergence of the Solar system - September 9 The formation of planet Earth - September 14 The appearance of life on Earth - September 25 The formation of the earth's oldest mountains - October 2 The time of formation of the oldest fossils (bacteria and blue-green algae) - October 9 The emergence of sexual reproduction - November 1 The oldest photosynthetic plants - November 12 Eukaryotes (the first cells containing nuclei) - November 15
Table II Cosmic calendar December Number 1 Formation of an oxygen atmosphere on Earth. 5 Intense volcanic eruptions and the formation of canals on Mars. 16 The first worms. 17 The end of the Precambrian period. Paleozoic era and the beginning of the Cambrian period. The emergence of invertebrates. 18 The first oceanic plankton. The rise of trilobites. 19 Ordovician period. The first fish, the first vertebrates. 20 Silur. The first spore plants. Plants conquer land. 21 Beginning of the Devonian period. The first insects. Animals colonize land. 22 The first amphibians. The first winged insects. 23 Carboniferous period. The first trees. The first reptiles. 24 Beginning of the Permian period. The first dinosaurs. 25 The end of the Paleozoic era. Beginning of the Mesozoic era. 26 Triassic period. The first mammals. 27 Jurassic period. The first birds. 28 Cretaceous period. First flowers. The extinction of dinosaurs. 29 The end of the Mesozoic era. Cenozoic era and the beginning of the Tertiary period. The first cetaceans. The first primates. 30 Beginning of development of the frontal lobes of the cerebral cortex in primates. The first hominids. The rise of giant mammals. 31 The end of the Pliocene period. Quaternary (Pleistocene and Holocene) period. The first people.
Table III December 31, Hours, minutes, seconds Appearance of Proconsul and Ramapithecus, possible ancestors of apes and humans 13.30.00 The first people 22.30.00 Widespread use of stone tools 23.00.00 Use of fire by the Peking people man 23.46.00 Beginning of the last glaciation period 23.56.00 Settlement of Australia 23.58.00 Flourishing of cave painting in Europe 23.59.00 Discovery of agriculture 23.59.20 Neolithic civilization - the first cities 23.59.35 First dynasties in Sumer and Egypt, development of astronomy 23.59.50 Opening a letter; state of Akkad; Laws of Hammurabi in Babylonia; Middle Kingdom in Egypt 23.59.52 Bronze metallurgy; Mycenaean culture; Trojan War: Olmec Culture; invention of the compass 23.59.53 Iron metallurgy; first Assyrian Empire; Kingdom of Israel; founding of Carthage by the Phoenicians 59/23/54 Qin Dynasty in China; Ashoka's empire in India: Athens during the time of Pericles; birth of Buddha 23.59.55 Euclidean geometry; Archimedean physics; Ptolemaic astronomy; The Roman Empire; birth of Christ 23.59.56 Introduction of zero and decimal counting in Indian arithmetic; decline of Rome; Muslim conquests 23.59.57 Mayan civilization; Song Dynasty in China; Byzantine Empire; Mongol invasion; Crusades 59.23.58 Renaissance in Europe; travels and geographical discoveries made by Europeans and Chinese during the Ming Dynasty, introduction of the experimental method into science 59/23/59
Wide development of science and technology; the emergence of global culture; the creation of means capable of destroying the human race, the first steps in space exploration and the search for extraterrestrial intelligence - The present moment and in the first seconds of the New Year The sidereal era of the evolution of the Universe will end in about 1014 years. This period is 10 thousand times longer than the time that supposedly passed from the beginning of the expansion of the Universe to the present day. Next will come the turn of galaxies consisting of hundreds and hundreds of billions of stars. In the centers of galaxies, there are supermassive black holes. For the future of galaxies, very rare events in our time are important, when a star, as a result of gravitational interaction with other stars, acquires high speed, leaves the galaxy and turns into an intergalactic wanderer. Stars will gradually leave the galaxy , and its central part will gradually shrink, turning into a very compact star cluster. In such a cluster, stars will collide with each other, turning into gas, and this gas will mainly fall into the central supermassive hole, increasing its mass. The final stage is a supermassive "black hole" that swallowed up the remains of the stars in the central part of the galaxy, and the dispersion of about 90% of all the stars in the outer parts in space. The process of destruction of galaxies will end in about 1019 years, by this time all the stars will have long gone out and lost the right to be called stars.
The average lifetime of a proton is estimated to be approximately 1032 years. The final product of proton decay is one positron, radiation in the form of a photon, a neutrino, and possibly one or more electron-positron pairs. So, in about 1032 years, nuclear matter will completely disintegrate. Even extinct stars will disappear from the world. After 1032 years, all nuclear matter will completely disintegrate, stars and planets will turn into photons and neutrinos. And “black holes” are not eternal. In the gravitational field near a “black hole,” as we know, the birth of particles occurs; Moreover, “black holes” with a mass on the order of stellar mass or more produce radiation quanta. This process leads to a decrease in the mass of the “black hole”; it gradually turns into photons, neutrinos, and gravitons. A “black hole” with a mass of 10 solar masses will evaporate in 1069 years, and a super massive “black hole”, the mass of which is another billion times greater, will evaporate in 1096 years. Due to the expansion of the Universe, the radiation density, as already mentioned, falls faster than the electronic density -positron plasma, and in 10,100 years this particular plasma will become dominant, and besides it, there will be practically nothing left in the Universe. At the age of the Universe of 10,100 years, the world will remain practically only electrons and positrons, scattered in space with a terribly insignificant density: one particle will account for a volume equal to 10185 volumes of everything visible today.
Photographs from the surface of Mars show traces of a dried-up stream. As reported on the agency's website on September 27, photographs taken by the Curiosity rover in Gale Crater show pebbles brought by an ancient stream. Latest astronomy news, 09-10.2012:
Experiments on the Radioastron projecthttp://ria.ru/science/20120918/753411048.htmlRoscosmos announced the start of accepting applications for scientific experiments on the Radioastron project, the press service of the Federal Space Agency announced. "The first open competition for scientific research has been announced applications for the ground-space interferometer "Radioastron" for the observation period July 2013 - June 2014 inclusive," the message notes. Latest astronomy news, 2012.
Introduction
Main part
1.Cosmology
2.Structure of the universe:
2.1.Metagalaxy
2.2.Galaxies
2.3.Stars
2.4Planet and solar system
3.Means for observing objects of the Universe
4.The problem of searching for extraterrestrial civilizations
Conclusion
Introduction
The Universe is the most global object of the megaworld, limitless in time and space. According to modern ideas, it is a huge, vast sphere. There are scientific hypotheses of an “open”, that is, a “continuously expanding” Universe, as well as a “closed”, that is, a “pulsating” Universe. Both hypotheses exist in several versions. However, very thorough research is required until one or another of them turns into a more or less well-founded scientific theory.
The Universe at various levels, from conventionally elementary particles to giant superclusters of galaxies, is characterized by structure. The structure of the Universe is the subject of study of cosmology, one of the important branches of natural science, located at the intersection of many natural sciences: astronomy, physics, chemistry, etc. The modern structure of the Universe is the result of cosmic evolution, during which galaxies were formed from protogalaxies, stars from protostars, protoplanetary cloud - planet.
Cosmology
Cosmology is an astrophysical theory of the structure and dynamics of change in the Metagalaxy, which includes a certain understanding of the properties of the entire Universe.
The term “cosmology” itself is derived from two Greek words: cosmos - Universe and logos - law, doctrine. At its core, cosmology is a branch of natural science that uses the achievements and methods of astronomy, physics, mathematics, and philosophy. The natural scientific basis of cosmology is astronomical observations of the Galaxy and other stellar systems, general relativity, physics of microprocesses and high energy densities, relativistic thermodynamics and a number of other new physical theories.
Many provisions of modern cosmology seem fantastic. The concepts of the Universe, infinity, and the Big Bang are not amenable to visual physical perception; such objects and processes cannot be captured directly. Because of this circumstance, one gets the impression that we are talking about something supernatural. But such an impression is deceptive, since the functioning of cosmology is very constructive, although many of its provisions turn out to be hypothetical.
Modern cosmology is a branch of astronomy that combines data from physics and mathematics, as well as universal philosophical principles, so it represents a synthesis of scientific and philosophical knowledge. Such a synthesis in cosmology is necessary because thoughts about the origin and structure of the Universe are empirically difficult to test and most often exist in the form of theoretical hypotheses or mathematical models. Cosmological research usually develops from theory to practice, from model to experiment, and here the initial philosophical and general scientific principles become of great importance. For this reason, cosmological models differ significantly from each other - they are often based on opposing initial philosophical principles. In turn, any cosmological conclusions also influence general philosophical ideas about the structure of the Universe, i.e. change a person’s fundamental ideas about the world and himself.
The most important postulate of modern cosmology is that the laws of nature, established by studying a very limited part of the Universe, can be extrapolated to much wider areas, and, ultimately, to the entire Universe. Cosmological theories differ depending on what physical principles and laws they are based on. The models built on their basis must allow testing for the observable region of the Universe, and the conclusions of the theory must be confirmed by observations or, in any case, not contradict them.
Structure of the Universe
Metagalaxy
A metagalaxy is a part of the Universe that can be studied by astronomical means. It consists of hundreds of billions of galaxies, each of which rotates around its own axis and simultaneously scatters from each other at speeds from 200 to 150,000 km. sec.(2).
One of the most important properties of the Metagalaxy is its constant expansion, as evidenced by the “expansion” of galaxy clusters. Evidence that galaxy clusters are moving away from each other comes from the "red shift" in galaxy spectra and the discovery of the CMB (extragalactic background radiation corresponding to a temperature of about 2.7 K) (1).
An important consequence follows from the phenomenon of expansion of the Metagalaxy: in the past, the distances between galaxies were smaller. And if we take into account that the galaxies themselves in the past were extended and rarefied gas clouds, then it is obvious that billions of years ago the boundaries of these clouds closed and formed a single homogeneous gas cloud that experienced constant expansion.
Another important property of the Metagalaxy is the uniform distribution of matter in it (the bulk of which is concentrated in stars). In its present state, the Metagalaxy is homogeneous on a scale of about 200 Mpc. It's unlikely that she was like this in the past. At the very beginning of the expansion of the Metagalaxy, inhomogeneity of matter could well have existed. The search for traces of heterogeneity in past states of the Metagalaxy is one of the most important problems of extragalactic astronomy(2).
The homogeneity of the Metagalaxy (and the Universe) must also be understood in the sense that the structural elements of distant stars and galaxies, the physical laws to which they obey, and physical constants, apparently, are the same everywhere with a high degree of accuracy, i.e. the same as in our region of the Metagalaxy, including the Earth. A typical galaxy hundreds of millions of light-years away looks basically the same as ours. The spectra of atoms, therefore, the laws of chemistry and atomic physics there are identical to those accepted on Earth. This circumstance makes it possible to confidently extend the laws of physics discovered in an earthly laboratory to wider areas of the Universe.
The idea of the homogeneity of the Metagalaxy once again proves that the Earth does not occupy any privileged position in the Universe. Of course, the Earth, the Sun and the Galaxy seem important and exceptional to us humans, but for the Universe as a whole they are not.
According to modern concepts, the Metagalaxy is characterized by a cellular (mesh, porous) structure. These ideas are based on astronomical observational data, which have shown that galaxies are not evenly distributed, but are concentrated near the boundaries of cells, within which there are almost no galaxies. In addition, huge volumes of space have been found in which galaxies have not yet been discovered.
If we take not individual sections of the Metagalaxy, but its large-scale structure as a whole, then it is obvious that in this structure there are no special, distinctive places or directions and the matter is distributed relatively evenly.
The age of the Metagalaxy is close to the age of the Universe, since the formation of its structure occurs in the period following the separation of matter and radiation. According to modern data, the age of the Metagalaxy is estimated at 15 billion years. Scientists believe that the age of galaxies that formed at one of the initial stages of the expansion of the Metagalaxy is apparently close to this.
Galaxies
A galaxy is a collection of stars in a lens-shaped volume. Most of the stars are concentrated in the plane of symmetry of this volume (the galactic plane), a smaller part is concentrated in the spherical volume (the galactic core).
In addition to stars, galaxies include interstellar matter (gases, dust, asteroids, comets), electromagnetic and gravitational fields, and cosmic radiation. The solar system is located near the galactic plane of our galaxy. For an observer on Earth, the stars concentrated in the galactic plane merge into the visible picture of the Milky Way.
The systematic study of galaxies began at the beginning of the last century, when instruments were installed on telescopes for the spectral analysis of light emissions from stars.
American astronomer E. Hubble developed a method for classifying galaxies known to him at that time, taking into account their observed shape. His classification identifies several types (classes) of galaxies, each of which has subtypes or subclasses. He also determined the approximate percentage distribution of observed galaxies: elliptical in shape (approximately 25%), spiral (approximately 50%), lenticular (approximately 20%) and peculiar (irregularly shaped) galaxies (approximately 5%) (2).
Elliptical galaxies have the spatial shape of an ellipsoid with varying degrees of compression. They are the simplest in structure: the distribution of stars uniformly decreases from the center.
Irregular galaxies do not have a distinct shape and lack a central core.
Spiral galaxies are presented in a spiral shape, including spiral arms. This is the most numerous type of galaxy, which includes our Galaxy - the Milky Way.
The Milky Way is clearly visible on a moonless night. It appears to be a cluster of luminous nebulous masses stretching from one side of the horizon to the other, and consists of approximately 150 billion stars. It is shaped like a flattened ball. In its center there is a core, from which several spiral stellar branches extend. Our Galaxy is extremely large: from one edge to the other, a light beam travels about 100 thousand Earth years. Most of its stars are concentrated in a giant disk about 1,500 light-years thick. At a distance of about 2 million light years from us is the closest galaxy to us - the Andromeda Nebula, which in its structure resembles the Milky Way, but significantly exceeds it in size. Our Galaxy, the Andromeda Nebula, together with other neighboring star systems form a local group of galaxies. The Sun is located at a distance of about 30 thousand light years from the center of the Galaxy.
Today it is known that galaxies unite into stable structures (clusters and superclusters of galaxies). Astronomers know a galaxy cloud with a density of 220,032 galaxies per square degree. Our Galaxy is part of a cluster of galaxies called the Local System.
The Local System includes our Galaxy, the Andromeda galaxy, the spiral galaxy from the constellation Triangulum and 31 other star systems. The diameter of this system is 7 million light years. This association of galaxies includes the Andromeda Galaxy, which is significantly larger than our Galaxy: its diameter is more than 300 thousand light years. years. It is located at a distance of 2.3 million sv. years from our Galaxy and consists of several billion stars. Along with such a huge galaxy as the Andromeda Nebula, astronomers are aware of dwarf galaxies (3).
Almost spherical galaxies measuring 3000 light-years in size were discovered in the constellations Leo and Sculptor. years in diameter. There is data on the linear sizes of the following large-scale structures in the Universe: stellar systems - 108 km, galaxies containing about 1013 stars - 3,104 light. years, galaxy cluster (of 50 bright galaxies) - 107 sv. years, superclusters of galaxies - 109 sv. years. The distance between galaxy clusters is approximately 20 107 ly. years(1).
The designation of galaxies is usually given relative to the corresponding catalog: catalog designation plus galaxy number (NGC2658, where NGC is Dreyer's new general catalog, 2658 is the number of the galaxy in this catalogue). In the first star catalogs, galaxies were mistakenly recorded as nebulae of a certain luminosity. In the second half of the twentieth century. It was found that the Hubble classification of galaxies is not accurate: there are many varieties of galaxies with peculiar shapes. The Local System (cluster of galaxies) is part of a giant supercluster of galaxies, the diameter of which is 100 million years; our Local System is located at a distance of more than 30 million light years from the center of this supercluster. years(1). Modern astronomy uses a wide range of methods for studying objects located at great distances from the observer. The method of radiological measurements, developed at the beginning of the last century, occupies a large place in astronomical research.
Stars
The world of stars is incredibly diverse. And although all stars are hot balls like the Sun, their physical characteristics differ quite significantly. (1) There are, for example, stars - giants and supergiants. They are larger than the Sun.
In addition to giant stars, there are also dwarf stars, which are significantly smaller in size than the Sun. Some dwarfs are smaller than the Earth and even the Moon. In white dwarfs, thermonuclear reactions practically do not occur; they are possible only in the atmosphere of these stars, where hydrogen enters from the interstellar medium. Basically, these stars shine due to huge reserves of thermal energy. Their cooling time is hundreds of millions of years. Gradually, the white dwarf cools down, its color changes from white to yellow, and then to red. Finally, it turns into a black dwarf - a dead, cold small star the size of the globe that cannot be seen from another planetary system (3).
There are also neutron stars - these are huge atomic nuclei.
Stars have different surface temperatures - from several thousand to tens of thousands of degrees. Accordingly, the color of the stars is also distinguished. Relatively “cold” stars with a temperature of 3–4 thousand degrees are red. Our Sun, with a surface “heated” to 6 thousand degrees, has a yellowish color. The hottest stars - with temperatures above 12 thousand degrees - are white and bluish.
Stars do not exist in isolation, but form systems. The simplest star systems consist of 2 or more stars. Stars are also united into even larger groups - star clusters.
The age of stars varies over a fairly wide range of values: from 15 billion years, corresponding to the age of the Universe, to hundreds of thousands - the youngest. There are stars that are currently being formed and are in the protostellar stage, that is, they have not yet become real stars.
The birth of stars occurs in gas-dust nebulae under the influence of gravitational, magnetic and other forces, due to which unstable homogeneities are formed and diffuse matter breaks up into a series of condensations. If such condensations persist long enough, then over time they turn into stars. It is important to note that the birth process is not of an individual isolated star, but of stellar associations.
The star is a plasma ball. The bulk (98-99%) of visible matter in the part of the Universe known to us is concentrated in stars. Stars are powerful sources of energy. In particular, life on Earth owes its existence to the radiation energy of the Sun.
A star is a dynamic, directionally changing plasma system. During the life of a star, its chemical composition and distribution of chemical elements change significantly. At later stages of development, stellar matter passes into the state of degenerate gas (in which the quantum mechanical influence of particles on each other significantly affects its physical properties - pressure, heat capacity, etc.), and sometimes neutron matter (pulsars - neutron stars, bursters - X-ray sources, etc.).
Stars are born from cosmic matter as a result of its condensation under the influence of gravitational, magnetic and other forces. Under the influence of universal gravitational forces, a dense ball is formed from a gas cloud - a protostar, the evolution of which goes through three stages.
The first stage of evolution is associated with the separation and compaction of cosmic matter. The second represents the rapid compression of a protostar. At some point, the gas pressure inside the protostar increases, which slows down the process of its compression, but the temperature in the internal regions still remains insufficient for the start of a thermonuclear reaction. At the third stage, the protostar continues to contract and its temperature rises, which leads to the onset of a thermonuclear reaction. The pressure of the gas flowing out of the star is balanced by the force of gravity, and the gas ball stops compressing. An equilibrium object is formed - a star. Such a star is a self-regulating system. If the temperature inside does not increase, the star inflates. In turn, the cooling of the star leads to its subsequent compression and heating, and nuclear reactions in it accelerate. Thus, the temperature balance is restored. The process of transforming a protostar into a star lasts for millions of years, which is relatively short on a cosmic scale.
The birth of stars in galaxies occurs continuously. This process also compensates for the continuously occurring death of stars. Therefore, galaxies consist of old and young stars. The oldest stars are concentrated in globular clusters, their age is comparable to the age of the galaxy. These stars formed as the protogalactic cloud broke up into smaller and smaller clumps. Young stars (about 100 thousand years old) exist due to the energy of gravitational compression, which heats the central region of the star to a temperature of 10-15 million K and “triggers” the thermonuclear reaction of converting hydrogen into helium. It is the thermonuclear reaction that is the source of the stars’ own glow.
From the moment the thermonuclear reaction begins, converting hydrogen into helium, a star like our Sun moves to the so-called main sequence, according to which the characteristics of the star will change over time: its luminosity, temperature, radius, chemical composition and mass. After hydrogen burns out, a helium core forms in the central zone of the star. Hydrogen thermonuclear reactions continue to occur, but only in a thin layer near the surface of this core. Nuclear reactions move to the periphery of the star. The burnt-out core begins to shrink, and the outer shell begins to expand. The shell swells to colossal sizes, the external temperature becomes low, and the star enters the red giant stage. From this moment on, the star enters the final stage of her life. Our Sun expects this in about 8 billion years. At the same time, its size will increase to the orbit of Mercury, and perhaps even to the orbit of the Earth, so that nothing will remain of the terrestrial planets (or melted rocks will remain).
The red giant is characterized by low external but very high internal temperatures. At the same time, increasingly heavier nuclei are included in thermonuclear processes, which leads to the synthesis of chemical elements and the continuous loss of matter by the red giant, which is ejected into interstellar space. Thus, in just one year the Sun, being in the red giant stage, can lose one millionth of its weight. In just ten to one hundred thousand years, only the central helium core remains from the red giant, and the star becomes a white dwarf. Thus, the white dwarf matures inside the red giant, and then sheds the remnants of the shell, the surface layers, which form a planetary nebula surrounding the star.
White dwarfs are small in size - their diameter is even smaller than the diameter of the Earth, although their mass is comparable to the Sun. The density of such a star is billions of times greater than the density of water. A cubic centimeter of its substance weighs more than a ton. Nevertheless, this substance is a gas, albeit of monstrous density. The substance that makes up a white dwarf is a very dense ionized gas consisting of atomic nuclei and individual electrons.
In white dwarfs, thermonuclear reactions practically do not occur; they are possible only in the atmosphere of these stars, where hydrogen enters from the interstellar medium. Basically, these stars shine due to huge reserves of thermal energy. Their cooling time is hundreds of millions of years. Gradually, the white dwarf cools down, its color changes from white to yellow, and then to red. Finally, it turns into a black dwarf - a dead, cold small star the size of the globe that cannot be seen from another planetary system.
More massive stars develop somewhat differently. They live only a few tens of millions of years. Hydrogen burns out in them very quickly, and they turn into red giants in just 2.5 million years. At the same time, the temperature in their helium core rises to several hundred million degrees. This temperature makes it possible for carbon cycle reactions to occur (fusion of helium nuclei, leading to the formation of carbon). The carbon nucleus, in turn, can attach another helium nucleus and form the nucleus of oxygen, neon, etc. all the way to silicon. The burning core of the star contracts, and the temperature in it rises to 3-10 billion degrees. Under such conditions, the combination reactions continue until the formation of iron nuclei - the most stable chemical element in the entire sequence. Heavier chemical elements - from iron to bismuth - are also formed in the depths of red giants, in the process of slow neutron capture. In this case, energy is not released, as in thermonuclear reactions, but, on the contrary, is absorbed. As a result, the compression of the star is accelerating (4).
The formation of the heaviest nuclei, which close the periodic table, presumably occurs in the shells of exploding stars, during their transformation into novae or supernovae, which some red giants become. In a slagged star, the equilibrium is disturbed; the electron gas is no longer able to withstand the pressure of the nuclear gas. Collapse occurs - a catastrophic compression of the star, it “explodes inward.” But if the repulsion of particles or any other reasons still stop this collapse, a powerful explosion occurs - a supernova explosion. At the same time, not only the star’s shell, but also up to 90% of its mass is thrown into the surrounding space, which leads to the formation of gas nebulae. At the same time, the luminosity of the star increases billions of times. Thus, a supernova explosion was recorded in 1054. In Chinese chronicles, it was recorded that it was visible during the day, like Venus, for 23 days. In our time, astronomers have found that this supernova left behind the Crab Nebula, which is a powerful source of radio emission (5).
The explosion of a supernova is accompanied by the release of a monstrous amount of energy. In this case, cosmic rays are generated, which greatly increase the natural background radiation and normal doses of cosmic radiation. Thus, astrophysicists have calculated that approximately once every 10 million years, supernovae erupt in close proximity to the Sun, increasing the natural background by 7 thousand times. This is fraught with serious mutations of living organisms on Earth. In addition, during a supernova explosion, the entire outer shell of the star is dumped along with the “slag” that has accumulated in it - chemical elements, the results of nucleosynthesis. Therefore, the interstellar medium relatively quickly acquires all currently known chemical elements heavier than helium. Stars of subsequent generations, including the Sun, from the very beginning contain an admixture of heavy elements in their composition and in the composition of the gas and dust cloud surrounding them (5).
Planets and solar system
The solar system is a star-planet system. There are approximately 200 billion stars in our Galaxy, among which experts believe that some stars have planets. The Solar System includes a central body, the Sun, and nine planets with their satellites (more than 60 satellites are known). The diameter of the solar system is more than 11.7 billion km. (2).
At the beginning of the 21st century. An object was discovered in the solar system, which astronomers named Sedna (the name of the Eskimo goddess of the ocean). Sedna has a diameter of 2000 km. One revolution around the Sun is 10,500 Earth years(7).
Some astronomers call this object a planet in the solar system. Other astronomers call planets only those space objects that have a central core with a relatively high temperature. For example, the temperature in the center of Jupiter is estimated to reach 20,000 K. Since Sedna is currently located at a distance of about 13 billion km from the center of the Solar system, information about this object is quite scarce. At the farthest point of the orbit, the distance from Sedna to the Sun reaches a huge value - 130 billion km.
Our star system includes two belts of minor planets (asteroids). The first is located between Mars and Jupiter (contains more than 1 million asteroids), the second is beyond the orbit of the planet Neptune. Some asteroids have a diameter of more than 1000 km. The outer boundaries of the Solar system are surrounded by the so-called Oort cloud, named after the Dutch astronomer who hypothesized the existence of this cloud in the last century. Astronomers believe that the edge of this cloud closest to the Solar System consists of ice floes of water and methane (comet nuclei), which, like the smallest planets, revolve around the Sun under the influence of its gravity at a distance of over 12 billion km. The number of such miniature planets is in the billions (2).
The solar system is a group of celestial bodies, very different in size and physical structure. This group includes: the Sun, nine large planets, dozens of planetary satellites, thousands of small planets (asteroids), hundreds of comets, countless meteorite bodies. All these bodies are united into one system due to the gravitational force of the central body - the Sun. The solar system is an ordered system that has its own structural laws. The unified nature of the solar system is manifested in the fact that all the planets revolve around the sun in the same direction and in almost the same plane. The sun, planets, satellites of planets rotate around their axes in the same direction in which they move along their trajectories. The structure of the solar system is also natural: each subsequent planet is approximately twice as far from the Sun as the previous one (2).
The solar system was formed approximately 5 billion years ago, with the Sun being a second generation star. Modern concepts of the origin of the planets of the Solar System are based on the fact that it is necessary to take into account not only mechanical forces, but also others, in particular electromagnetic ones. It is believed that it was electromagnetic forces that played a decisive role in the birth of the Solar System (2).
According to modern ideas, the original gas cloud from which both the Sun and the planets were formed consisted of ionized gas subject to the influence of electromagnetic forces. After the Sun was formed from a huge gas cloud through concentration, small parts of this cloud remained at a very large distance from it. The gravitational force began to attract the remaining gas to the resulting star - the Sun, but its magnetic field stopped the falling gas at a distance - just where the planets are located. The gravitational constant and magnetic forces influenced the concentration and condensation of the falling gas, and as a result, planets were formed. When the largest planets arose, the same process was repeated on a smaller scale, thus creating satellite systems.
There are several mysteries in the study of the solar system.
1. Harmony in the movement of planets. All planets in the solar system revolve around the sun in elliptical orbits. The movement of all the planets of the Solar System occurs in the same plane, the center of which is located in the central part of the equatorial plane of the Sun. The plane formed by the orbits of the planets is called the ecliptic plane.
2. All planets and the Sun rotate around their own axis. The rotation axes of the Sun and planets, with the exception of the planet Uranus, are directed, roughly speaking, perpendicular to the ecliptic plane. Uranus' axis is directed almost parallel to the ecliptic plane, i.e. it rotates lying on its side. Another feature of it is that it rotates around its axis in a different direction, like Venus, unlike the Sun and other planets. All other planets and the Sun rotate against the direction of the clock hand. Uranus has 15 satellites.
3. Between the orbits of Mars and Jupiter there is a belt of minor planets. This is the so-called asteroid belt. Minor planets have a diameter from 1 to 1000 km. Their total mass is less than 1/700th the mass of the Earth.
4. All planets are divided into two groups (terrestrial and unearthly). The first are planets with high density; heavy chemical elements occupy the main place in their chemical composition. They are small in size and rotate slowly around their axis. This group includes Mercury, Venus, Earth and Mars. Currently, it is suggested that Venus is the past of the Earth, and Mars is its future.
The second group includes: Jupiter, Saturn, Uranus, Neptune and Pluto. They consist of light chemical elements, rotate quickly around their axis, orbit the Sun slowly and receive less radiant energy from the Sun. Below (in the table) data is given on the average surface temperature of the planets on the Celsius scale, the length of day and night, the length of the year, the diameter of the planets of the solar system and the mass of the planet in relation to the mass of the Earth (taken as 1).
The distance between the orbits of the planets approximately doubles when moving from each of them to the next - the “Titius-Bode Rule”, observed in the arrangement of the planets.
When considering the true distances of the planets to the Sun, it turns out that Pluto in some periods is closer to the Sun than Neptune, and, therefore, it changes its ordinal number according to the Titius-Bode rule.
The mystery of the planet Venus. In the ancient astronomical sources of China, Babylon, and India, 3.5 thousand years old, there is no mention of Venus. American scientist I. Velikovsky in the book “Colliding Worlds,” which appeared in the 50s. XX century, hypothesized that the planet Venus took its place only recently, during the formation of ancient civilizations. Approximately once every 52 years, Venus comes close to Earth, at a distance of 39 million km. During the period of great opposition, every 175 years, when all the planets line up one after another in the same direction, Mars approaches the Earth at a distance of 55 million km.
Means of observing objects of the Universe
Modern astronomical instruments are used to measure the exact positions of luminaries on the celestial sphere (systematic observations of this kind make it possible to study the movements of celestial bodies); to determine the speed of movement of celestial bodies along the line of sight (radial velocities): to calculate the geometric and physical characteristics of celestial bodies; to study physical processes occurring in various celestial bodies; to determine their chemical composition and for many other studies of celestial objects that astronomy deals with. All information about celestial bodies and other space objects is obtained by studying various radiations coming from space, the properties of which are directly dependent on the properties of celestial bodies and on the physical processes occurring in space. In this regard, the main means of astronomical observations are receivers of cosmic radiation, and primarily telescopes that collect the light of celestial bodies.
Currently, three main types of optical telescopes are used: lens telescopes, or refractors, mirror telescopes, or reflectors, and mixed mirror-lens systems. The power of a telescope directly depends on the geometric dimensions of its lens or mirror that collects light. Therefore, recently, reflecting telescopes have become increasingly used, since according to technical conditions it is possible to manufacture mirrors with significantly larger diameters than optical lenses.
Modern telescopes are very complex and advanced units, the creation of which uses the latest advances in electronics and automation. Modern technology has made it possible to create a number of devices and devices that have greatly expanded the possibilities of astronomical observations: television telescopes make it possible to obtain clear images of planets on the screen, electron-optical converters allow observations in invisible infrared rays, and telescopes with automatic correction compensate for the influence of atmospheric interference. In recent years, new receivers of cosmic radiation - radio telescopes, which make it possible to look into the depths of the Universe much further than the most powerful optical systems, have become increasingly widespread.
Radio astronomy, which emerged in the early 1930s, has significantly enriched our understanding of the Universe. of our century. In 1943, Soviet scientists L.I., Mandelstam and N.D. Papaleksi theoretically substantiated the possibility of radar detection of the Moon (10).
Radio waves sent by man reached the Moon and, reflected from it, returned to Earth. 50s of the 20th century. - a period of unusually rapid development of radio astronomy. Every year, radio waves brought from space new amazing information about the nature of celestial bodies. Today, radio astronomy uses the most sensitive receiving devices and the largest antennas. Radio telescopes have penetrated into depths of space that are still inaccessible to conventional optical telescopes. The radio cosmos opened up before man - the picture of the Universe in radio waves (10).
There are also a number of astronomical instruments that have specific purposes and are used for specific research. Such instruments include, for example, a solar tower telescope built by Soviet scientists and installed at the Crimean Astrophysical Observatory.
Various sensitive instruments are increasingly used in astronomical observations, making it possible to capture thermal and ultraviolet radiation from celestial bodies and to record objects invisible to the eye on a photographic plate.
The next stage of transatmospheric observations was the creation of orbital astronomical observatories (OAO) on artificial Earth satellites. Such observatories, in particular, are the Soviet Salyut orbital stations. Orbital astronomical observatories of various types and purposes have become firmly established in practice (9).
During astronomical observations, series of numbers, astrophotographs, spectrograms and other materials are obtained, which must be subjected to laboratory processing for final results. This processing is carried out using laboratory measuring instruments. Electronic computers are used to process the results of astronomical observations.
Coordinate measuring machines are used to measure the positions of images of stars on astrophotographs and images of artificial satellites relative to stars on satellitegrams. Microphotometers are used to measure blackening in photographs of celestial bodies and spectrograms. An important instrument necessary for observations is the astronomical clock (9).
The problem of searching for extraterrestrial civilizations
The development of natural science in the second half of the 20th century, outstanding discoveries in the field of astronomy, cybernetics, biology, and radiophysics made it possible to transfer the problem of extraterrestrial civilizations from a purely speculative and abstract theoretical perspective to a practical plane. For the first time in human history, it became possible to conduct deep and detailed experimental research on this important fundamental problem. The need for this kind of research is determined by the fact that the discovery of extraterrestrial civilizations and the establishment of contact with them can have a huge impact on the scientific and technological potential of society and have a positive impact on the future of humanity.
From the standpoint of modern science, the assumption about the possibility of the existence of extraterrestrial civilizations has objective grounds: the idea of the material unity of the world; about the development, evolution of matter as its universal property; natural science data about the regular, natural nature of the origin and evolution of life, as well as the origin and evolution of man on Earth; astronomical data that the Sun is a typical, ordinary star of our Galaxy and there is no reason to distinguish it from many other similar stars; at the same time, astronomy proceeds from the fact that there is a wide variety of physical conditions in the Cosmos, which can, in principle, lead to the emergence of the most diverse forms of highly organized matter.
An assessment of the possible prevalence of extraterrestrial (space) civilizations in our Galaxy is carried out using the Drake formula:
The current document contains no sources. N=R x f x n x k x d x q x L
where N is the number of extraterrestrial civilizations in the Galaxy; R is the rate of star formation in the Galaxy, averaged over the entire time of its existence (number of stars per year); f is the proportion of stars with planetary systems; n is the average number of planets included in planetary systems and environmentally suitable for life; k is the fraction of planets on which life actually arose; d – the proportion of planets on which, after the emergence of life, intelligent forms developed, q – the proportion of planets on which intelligent life reached a phase that provided the possibility of communication with other worlds and civilizations: L – the average duration of existence of such extraterrestrial (space, technical) civilizations( 3).
With the exception of the first quantity (R), which relates to astrophysics and can be calculated more or less accurately (about 10 stars per year), all other quantities are very, very uncertain, so they are determined by competent scientists based on expert estimates, which, of course, , are subjective.
The topic of contacts with extraterrestrial civilizations is perhaps one of the most popular in science fiction literature and cinema. As a rule, it arouses the most ardent interest among fans of this genre, everyone interested in the problems of the Universe. But the artistic imagination here must be subordinated to the strict logic of rational analysis. This analysis shows that the following types of contacts are possible: direct contacts, i.e. mutual (or one-way) visits; contacts via communication channels; contacts of a mixed type - sending automatic probes to an extraterrestrial civilization that transmit the received information via communication channels.
Currently, real possible contacts with extraterrestrial civilizations are contacts through communication channels. If the signal propagation time in both directions t is greater than the lifetime of civilization (t > L), then we can talk about one-way contact. If t<< L, то возможен двусторонний обмен информацией. Современный уровень естественнонаучных знаний позволяет серьезно говорить лишь о канале связи с помощью электромагнитных волн, а сегодняшняя радиотехника может реально обеспечить установление такой связи
The study of extraterrestrial civilizations must be preceded by the establishment of one form or another of communication with them. Currently, there are several directions for searching for traces of the activity of extraterrestrial civilizations (6).
Firstly, the search for traces of astrological engineering activities of extraterrestrial civilizations. This direction is based on the assumption that technically advanced civilizations must sooner or later move on to transforming the surrounding outer space (creating artificial satellites, artificial biosphere, etc.), in particular to intercept a significant part of the star’s energy. As calculations show, the radiation of the main part of such astrological engineering structures should be concentrated in the infrared region of the spectrum. Therefore, the task of detecting such extraterrestrial civilizations should begin with a search for local sources of infrared radiation or stars with an anomalous excess of infrared radiation. Such studies are currently underway. As a result, several dozen infrared sources were discovered, but so far there is no reason to connect any of them with an extraterrestrial civilization.
Secondly, the search for traces of visits by extraterrestrial civilizations on Earth. This direction is based on the assumption that the activity of extraterrestrial civilizations could manifest itself in the historical past in the form of a visit to Earth, and such a visit could not but leave traces in the monuments of the material or spiritual culture of various peoples. On this path there are many opportunities for various kinds of sensations - stunning “discoveries”, quasi-scientific myths about the cosmic origins of individual cultures (or their elements); Thus, the story of the astronauts is the name given to the legends about the ascension of saints to heaven. The so far inexplicable construction of large stone structures also does not prove their cosmic origin. For example, speculation of this kind around giant stone idols on Easter Island was dispelled by T. Heyerdahl: the descendants of the ancient population of this island showed him how it was done not only without the intervention of astronauts, but also without any technology. In the same row is the hypothesis that the Tunguska meteorite was not a meteorite or a comet, but an alien spaceship. These kinds of hypotheses and assumptions need to be investigated most carefully (6)
Thirdly, the search for signals from extraterrestrial civilizations. This problem is currently formulated primarily as the problem of searching for artificial signals in the radio and optical (for example, a highly directed laser beam) ranges. The most likely is radio communication. Therefore, the most important task is to select the optimal wave range for such communication. Analysis shows that the most likely artificial signals are at waves = 21 cm (hydrogen radio line), = 18 cm (OH radio line), = 1.35 cm (water vapor radio line) or on waves combined from the fundamental frequency with some mathematical constant, etc.).
A serious approach to searching for signals from extraterrestrial civilizations requires the creation of a permanent service covering the entire celestial sphere. Moreover, such a service should be quite universal - designed to receive signals of various types (pulse, narrowband and broadband). The first work on searching for signals from extraterrestrial civilizations was carried out in the USA in 1950. The radio emission of nearby stars (Cetus and Eridanus) at a wavelength of 21 cm was studied. Subsequently (70–80s), such studies were also carried out in the USSR. The research yielded encouraging results. Thus, in 1977 in the USA (Observatory of the University of Ohio), during a survey of the sky at a wavelength of 21 cm, a narrow-band signal was recorded, the characteristics of which indicated its extraterrestrial and, probably, artificial origin (8). However, this signal could not be re-registered, and the question of its nature remained open. Since 1972, searches in the optical range have been carried out at orbital stations. Projects for the construction of multi-mirror telescopes on Earth and the Moon, giant space radio telescopes, etc. were discussed.
Searching for signals from extraterrestrial civilizations is one aspect of contact with them. But there is another side - a message to such civilizations about our earthly civilization. Therefore, along with the search for signals from space civilizations, attempts were made to send a message to extraterrestrial civilizations. In 1974, from the radio astronomical observatory in Arecibo (Puerto Rico) towards the globular cluster M-31, located at a distance of 24 thousand light years from Earth, a radio message was sent containing coded text about life and civilization on Earth (8) . Information messages were also repeatedly placed on spacecraft, the trajectories of which provided them with exit beyond the solar system. Of course, there is very little chance that these messages will ever reach their goal, but we have to start somewhere. It is important that humanity not only seriously thinks about contacts with intelligent beings from other worlds, but is already able to establish such contacts, even in the simplest form.
Cosmic natural sources of radiation conduct constant intense “radio transmission” on meter waves. So that it does not create annoying interference, radio communication between inhabited worlds should be carried out at wavelengths of no more than 50 cm (11).
Shorter radio waves (several centimeters) are not suitable, since the thermal radio emission of planets occurs precisely at such waves, and it will “jam” artificial radio communications. In the United States, a project is being discussed to create a complex for receiving extraterrestrial radio signals, consisting of a thousand synchronous radio telescopes installed at a distance of 15 km from each other. In essence, such a complex is similar to one gigantic parabolic radio telescope with a mirror area of 20 km. The project is expected to be implemented over the next 10–20 years. The cost of the planned construction is truly astronomical - at least 10 billion dollars. The projected complex of radio telescopes will allow receiving artificial radio signals within a radius of 1000 light years (12).
In the last decade, the opinion has increasingly prevailed among scientists and philosophers that Humanity is alone, if not in the entire Universe, then, in any case, in our Galaxy. This opinion entails the most important ideological conclusions about the meaning and value of earthly civilization and its achievements.
Conclusion
The Universe is the entire existing material world, limitless in time and space and infinitely diverse in the forms that matter takes in the process of its development.
The universe in a broad sense is our environment. The important significance of human practical activity is the fact that the Universe is dominated by irreversible physical processes, that it changes over time and is in constant development. Man began to explore space and entered outer space. Our achievements are becoming increasingly widespread, global and even cosmic in scope. And in order to take into account their immediate and distant consequences, the changes that they can make to the state of our living environment, including the cosmic environment, we must study not only terrestrial phenomena and processes, but also patterns on a cosmic scale.
The impressive progress of the science of the Universe, begun by the great Copernican revolution, has repeatedly led to very profound, sometimes radical changes in the research activities of astronomers and, as a consequence, in the system of knowledge about the structure and evolution of cosmic objects. Nowadays, astronomy is developing at a particularly rapid pace, increasing every decade. The flow of outstanding discoveries and achievements irresistibly fills it with new content.
At the beginning of the 21st century, scientists are faced with new questions about the structure of the Universe, the answers to which they hope to obtain with the help of an accelerator - the Large Hadron Collider
The modern scientific picture of the world is dynamic and contradictory. It contains more questions than answers. It amazes, frightens, baffles, shocks. The quest for the knowing mind knows no bounds, and in the coming years we may be shocked by new discoveries and new ideas.
Bibliography
1. Naydysh V.M. Concepts of modern natural science: textbook \ed. 2nd, revised and additional - M.: Alfa-M; INFRA-M, 2004. - 622 p.
2. Lavrinenko V.N. Concepts of modern natural science: textbook\V.N. Lavrinenko, V.P. Ratnikova - M.: 2006. - 317 p.
3. Astronomy News, Universe, Astronomy, Philosophy: ed. MSU 1988. - 192 p.
4. Danilova V.S., Kozhevnikov N.I. Basic concepts of modern natural science: textbook\ M.: Aspect-press, 2000 - 256 p.
5. Karpenkov S.Kh. Modern natural science: textbook\M. Academic project 2003. - 560 p.
6. News of astronomy, cosmonautics, the Universe. - URL: universe-news.ru
7. Likhin A.F. Concepts of modern natural science: textbook\TK Welby, Prospekt Publishing House, 2006. - 264 p.
8. Tursunov A. Philosophy and modern cosmology M.\ INFRA-M, 2001, - 458 p.
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