The universe is the whole infinite world around us. These are other planets and stars, our planet Earth, its plants and animals, including what is outside the Earth- space, planets, stars. This is matter without end and edge, taking on the most diverse forms of its existence.
Some astronomers believe that in the beginning the Universe was a tight bunch of very dense matter. And then, about 15 billion years ago, this stuff exploded. The Big Bang happened. The primary matter exploded and began to expand. A lot of time passed, and stars and galaxies were formed from this cloud of hot gases. Galaxies to this day are moving away from each other, moving away from the center in all directions, which means that the Universe continues to expand. Even the most advanced astronomical tools cannot cover the entire universe
There is another theory of the origin of the universe. According to it, the origin of the Universe is a reasonable creative act carried out by God, the nature of which is incomprehensible to the human mind.
Some scientists have proposed the theory of the so-called "infinitely pulsating universe". According to this theory, the universe expands and then contracts to a singularity, then expands again and contracts again. It has no beginning and no end. This removes the question of the origin of the Universe - it does not arise from anywhere, but exists forever.
The anthropic (human) principle was first formulated in 1960 by Iglis G.I. , but he is, as it were, an unofficial author of it. And the official author was a scientist named Carter. The anthropic principle says that at the beginning of the universe there was a plan of the universe, the crown of this plan is the emergence of life, and the crown of life is man. The anthropic principle fits very well into the religious concept of life programming. The Anthropic Principle states that the universe is the way it is because there is an observer or he must appear at a certain stage of development.
Modern hypotheses about the origin of the universe
According to modern concepts, the Universe we are currently observing arose 13.7 ± 0.2 billion years ago from some initial singular state with gigantic temperature and density and has been continuously expanding and cooling since then. AT recent times scientists were able to determine that the rate of expansion of the universe, starting from a certain point in the past, is constantly increasing, which refines some of the concepts of the Big Bang theory.
The successful explanation of a number of phenomena using the Big Bang model has led to the fact that, as a rule, there is no doubt about the reality of the origin of the microwave background radiation from an expanding primary fireball at the moment when the matter of the Universe became transparent. It is possible, however, that this is too simple an explanation. In 1978, trying to find a justification for the observed ratio of photons and baryons (baryons are "heavy" elementary particles, which, in particular, include protons and neutrons) - 108: 1, - M. Rees suggested that the background radiation may be the result of an "epidemic" of the formation of massive stars that began immediately after the separation of radiation from matter and before the age The universe has reached 1 billion years. The lifetime of these stars could not exceed 10 million years; many of them were destined to go through the supernova stage and throw heavy chemical elements into space, which partially gathered into grains solid, forming clouds of interstellar dust. This dust, heated by radiation from pre-galactic stars, could in turn emit infrared radiation, which, due to its redshift caused by the expansion of the universe, is now observed as microwave background radiation.
According to a new model for the formation of the universe, proposed by the astrophysicist at the State University of New York, Kenneth Lanzetta, for almost half a billion years after the Big Bang, formally considered the moment of its birth, everything in the world was plunged into darkness. And this darkness was "torn apart" by a gigantic stellar "explosion", as a result of which the universe began to take on the form that we observe today.
This theory completely refutes the already established view that star formation proceeded gradually after the Big Bang and reached its peak about 5 billion years ago. Based on the analysis of data obtained as a result of observations of "deep space" zones, Lanzetta concluded that the process of star formation began much earlier than the Big Bang and proceeded very rapidly. Moreover, the more intense the process was then and is happening now, the closer it took place at the hypothetical "edges of the universe."
According to one of the alternative theories (the so-called "infinitely pulsating Universe"), the world has never arisen and will never disappear (or in other words, it is born and dies an infinite number of times), but it has a periodicity, while the creation of the world is understood as the starting point after which the world rebuilt (it also marks the end of the world.
The structure of the universe
The universe appears to us everywhere the same - "continuous" and homogeneous. You can't think of a simpler device. I must say that people have long suspected this. Pointing out, for reasons of maximum simplicity of the device, the general homogeneity of the world, the remarkable thinker Pascal (1623-1662) said that the world is a circle, the center of which is everywhere, and the circumference is nowhere. Thus, with the help of a visual geometric image, he asserted the homogeneity of the world.
The Universe also has one more important property, but it was never even guessed at. The universe is in motion - it is expanding. The distance between clusters and superclusters is constantly increasing. They seem to run away from each other. And the mesh network is stretched.
At all times, people preferred to consider the Universe eternal and unchanging. This point of view prevailed until the 1920s. At that time, it was believed that it was limited by the size of our Galaxy. Paths can be born and die, the Galaxy still remains the same, just as a forest remains unchanged, in which trees change generation after generation.
A real revolution in the science of the Universe was made in 1922-1924 by the work of the Leningrad mathematician and physicist A. Fridman. Based on the general theory of relativity just created by A. Einstein, he mathematically proved that the world is not something frozen and unchanging. As a whole, he lives his dynamic life, changes in time, expanding or contracting according to strictly defined laws.
Friedman discovered the mobility of the stellar universe. This was a theoretical prediction, and the choice between expansion and contraction must be made based on astronomical observations. Such observations were made in 1928-1929 by Hubble, the explorer of galaxies already known to us.
He discovered that distant galaxies and their entire collectives are moving, moving away from us in all directions. But this is how the general expansion of the universe should look, in accordance with Friedman's predictions.
If the universe is expanding, then the clusters were closer together in the distant past. Moreover, it follows from Friedman's theory that fifteen to twenty billion years ago there were no stars or galaxies, and all matter was mixed and compressed to an enormous density. This substance was then unthinkably hot. From such a special state, the general expansion began, which eventually led to the formation of the Universe as we see and know it now.
General representations about the structure of the universe evolved throughout the history of astronomy. However, only in our century could appear the modern science of the structure and evolution of the universe - cosmology.
Part One ASTRONOMIC ASPECT OF THE PROBLEM
1. Scales 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, they could hardly successfully develop the science to which they devoted their lives. The spatio-temporal scales familiar to us from childhood are so insignificant compared to the cosmic scales that when it comes to consciousness, it literally takes your breath away. Dealing with some problem of 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 methods of observation, or builds in his imagination, consciously or unconsciously, some small model investigated space system. In this case, a correct understanding of the relative dimensions of the system under study (for example, the ratio of the dimensions of the details of a given space system, the ratio of the dimensions of this system and others similar or unlike it, etc.) and time intervals (for example, the ratio of the flow velocity of a given process to the rate of some other). The author of this book has done a lot of work, for example, on the solar corona and the Galaxy. And they always seemed to him irregular shape spheroidal bodies of approximately the same size - something about 10 cm ... Why 10 cm? This image arose subconsciously, simply because too often, thinking about this or that issue of solar or galactic physics, the author drew in an ordinary notebook (in a box) the outlines of the subjects of his thoughts. He drew, trying to adhere to the scale of phenomena. On one very curious 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 one. But he quietly forgot about it. And if, in a number of cases, the large dimensions of the galactic corona acquired some fundamental significance (it did happen), this was taken into account formally and mathematically. And all the same, visually both "crowns" seemed equally small... If the author, in the process of this work, 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 other equally correct subjects, work on the problems of the solar and galactic coronas would stop automatically... Let the reader forgive me this "lyrical digression". I have no doubt that other astronomers had the same thoughts when they worked on their problems. It seems to me that sometimes it is useful to get acquainted with the "kitchen" of scientific work... If we want to discuss exciting questions about the possibility of intelligent life in the Universe, then, first of all, it will be necessary to form a correct idea of its space-time scales. Until relatively recently, the globe seemed huge to man. It took the brave companions of Magellan over three years to make the first round-the-world trip 465 years ago at the cost of incredible hardships. A little over 100 years have passed since the time when the resourceful hero of a science fiction novel by Jules Verne made, using the latest technological advances of that time, a trip 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 the thoughts of people involuntarily turned to the vast expanses of space, in which the small planet Earth was lost ... Our Earth is one of the planets 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 the average distance from the Earth to the Sun. It is currently unknown whether there are planets in the solar system even more distant from the Sun than Pluto. It can only be argued that if such planets exist, they are relatively small. Conventionally, the size of the solar system can be taken equal to 50-100 astronomical units *, or about 10 billion km. On our earthly scale, this is a very large value, about 1 million larger than the diameter of the Earth.Rice. 1. Planets of the solar system
We can more visually represent the relative scales 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 at a distance of 280 cm from it on this scale. The Earth is at a distance of 760 cm, the giant planet Jupiter is removed at a distance of about 40 m, and the most distant planet is in many respects the still enigmatic Pluto - at a distance of about 300m. The dimensions of the globe on this scale are slightly larger than 0.5 mm, the lunar diameter is slightly larger 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 with him, interplanetary distances within the solar system seem to be mere trifles. Readers, of course, know that for measuring interstellar distances such a unit of length as a kilometer is never used **). This unit of measurement (as well as 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 science, to estimate interstellar and intergalactic distances, the "light year" is used as a unit of measurement. 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 9.46x10 12 km, or about 10,000 billion km. In the scientific literature, a special unit is usually used to measure interstellar and intergalactic distances, called the "parsec";
1 parsec (pc) is equal to 3.26 light year. 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 at 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 nearest neighbors of the solar system - is closer to us than 1 pc. For example, the mentioned Proxima Centauri is removed from us at a distance of about 1.3 pc. On the scale at which we depicted the solar system, this corresponds to 2 thousand km. All this well illustrates the great isolation of our solar system from the surrounding star systems, some of these systems may have many similarities with it. But the stars surrounding the Sun and the Sun itself constitute only a negligible part of the gigantic collective of stars and nebulae, which is called the "Galaxy". We see this cluster of stars on clear moonless nights as a strip 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 that make up it fill a volume that has the shape of a highly compressed ellipsoid of revolution. Often in popular literature the shape of the Galaxy is compared to a biconvex lens. In fact, everything is much more complicated, and the picture drawn is too rough. In fact, it turns out that different types of stars are concentrated to the center of the Galaxy and to its "equatorial plane" in completely different ways. 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 extremes spatial distribution(which astronomers call "flat" and "spherical") are all intermediate cases. Nevertheless, it turns out that the main part of the stars in the Galaxy is located in a giant disk, the diameter of which is about 100 thousand light years, and the thickness is about 1500 light years. In this disk, there are slightly more than 150 billion stars of various types. Our Sun is one of these stars, located on the periphery of the Galaxy near 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 nucleus of the Galaxy (or its center) is about 30 thousand light years. The 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 greater than the average stellar density in the vicinity of the Sun *** . In addition, stars tend to form separate groups or clusters. A good example of such a cluster is the Pleiades, which are visible in our winter sky (Figure 3). The Galaxy also contains structural details on a much larger scale. Recent studies have shown that nebulae, as well as hot massive stars, are distributed along the branches of the spiral. The spiral structure is especially well seen in other star systems - galaxies (with a small letter, in contrast to our star system - the Galaxy). One of these galaxies is shown in Fig. 4. Establishing the spiral structure of the Galaxy in which we ourselves find ourselves has proved extremely difficult.
Rice. 3. Photograph of the Pleiades star cluster
Rice. 4 Spiral Galaxy NGC 5364
The stars and nebulae within the Galaxy move in a rather complex way. 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 rigid body: various sections Galaxies have different rotation periods. Thus, the Sun and the stars surrounding it in a huge area of several hundred light-years in size make a complete revolution in about 200 million years. Since the Sun, together with the family of planets, has apparently existed for about 5 billion years, during its evolution (from its birth from a gaseous nebula to its current state) it has made about 25 revolutions around the axis of rotation of the Galaxy. We can say that the age of the Sun is only 25 "galactic years", to put it bluntly - the age is blooming ... The speed of the Sun and its neighboring stars in their almost circular galactic orbits reaches 250 km / s ****. This regular movement around the galactic core is superimposed by the chaotic, erratic movements of the stars. The speed of such movements is much lower - about 10-50 km / s, and for objects different types they are different. Hot massive stars have the least speed (6-8 km/s), solar-type stars have about 20 km/s. The lower these velocities, the more "flat" is the distribution of this type of stars. On the scale that we used to visualize the solar system, the dimensions of the Galaxy would be 60 million km - a value that is already quite close to the distance from the Earth to the Sun. From this it is clear that as one penetrates into more and more remote regions of the Universe, this scale is no longer suitable, since it loses visibility. 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. 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 - 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 is a unit of length equal to 10 -8 cm).
We have already emphasized that the stars are separated from each other by great distances, and thus practically isolated. In particular, this means that the stars almost never collide with each other, although the movement of each of them is determined by the gravitational force field created by all the stars in the Galaxy. If we consider the Galaxy as a certain region filled with gas, with stars playing the role of gaseous molecules and atoms, then we must consider this gas to be extremely rarefied. In the vicinity of the Sun, the average distance between stars is about 10 million times greater than the average diameter of the stars. Meanwhile, under normal conditions in ordinary air, the average distance between molecules is only a few tens of times greater than the dimensions 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 the stellar density is relatively high, collisions between stars will occur from time to time. Here, approximately one collision should be expected every million years, while in the "normal" regions of the Galaxy during the entire history of the evolution of our stellar system, which is at least 10 billion years, there were practically no collisions between stars (see Chap. 9 ).
We have briefly outlined the scale and the most general structure of the stellar system to which our Sun belongs. At the same time, those methods were not considered at all, with the help of which for many years several generations of astronomers, step by step, recreated the majestic picture of the structure of the Galaxy. 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 of the Universe. Such a picture is essential to the understanding of this book.
Rice. 5. Andromeda Nebula with satellites
For several decades, astronomers have been persistently studying other star systems that are more or less similar to ours. This area of research has been called "extragalactic astronomy". It now plays almost a leading role in astronomy. Over the past three decades, extragalactic astronomy has made astonishing progress. Little by little, the grandiose contours of the Metagalaxy began to emerge, in which our star system is included as a small particle. We still do not know everything about the Metagalaxy. The vast remoteness of objects creates very specific difficulties, which are resolved by using the most powerful means of observation in combination with deep theoretical research. Yet the overall structure of the Metagalaxy has largely become clear in recent years. We can define the Metagalaxy as a collection of star systems - galaxies moving in the vast expanses of the part of the Universe that 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 with the total length of our Galaxy. Another galaxy "close" to us is a nebula in the constellation Andromeda. It is visible to the naked eye as a faint spot of light of the 5th magnitude ***** . In fact, this is a huge stellar world, in terms of the number of stars and the total mass of three times the size of our Galaxy, which in turn is a giant among galaxies. The distance to the Andromeda Nebula, or, as astronomers call it, M 31 (which means that in the well-known catalog of Messier nebulae it is listed under No. 31), is about 1800 thousand light years, which is about 20 times the size of the Galaxy. The M 31 nebula has a pronounced spiral structure and, in many of its characteristics, is very similar to our Galaxy. Near it are its small ellipsoidal satellites (Fig. 5). On fig. Figure 6 shows photographs of several galaxies relatively close to us. The great variety of their forms attracts attention. Along with spiral systems (such galaxies are denoted by the symbols Sа, Sb and Sс depending on the nature of development spiral structure; in the presence of a “bar” passing through the nucleus (Fig. 6a), after the letter S, the letter B is put) there are spheroidal and ellipsoidal, devoid of any traces of a spiral structure, as well as “irregular” galaxies, a good example of which can be the Magellanic Clouds. Large telescopes observe a huge number of galaxies. If there are about 250 galaxies brighter than the visible 12th magnitude, then there are already about 50 thousand brighter than the 16th magnitude. The faintest objects that a reflecting telescope with a mirror diameter of 5 m can photograph at the limit have 24.5 magnitude. It turns out that among the billions of such weakest objects, the majority are galaxies. Many of them are distant from us at distances that light travels in 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. geological history Earth!.
Rice. 6a. "Crossed Spiral" Galaxy
Rice. 6b. Galaxy NGC 4594
Rice. 6s. Galaxies Magellanic Clouds
Sometimes amazing objects come across among galaxies, for example, "radio galaxies". These are star systems that radiate a huge amount of energy in the radio range. In some radio galaxies, the radio flux is several times greater than the optical flux, although in the optical range their luminosity is very high - several times greater than the total luminosity of our Galaxy. 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 light spots 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 removed from us at a great distance - 600 million light years. However, the flux of radio emission from Cygnus A at meter wavelengths is so great that it exceeds even the flux of radio emission from the Sun (during periods when there are no spots 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 you know, are inversely proportional to the squares of distances! The spectra of most galaxies resemble the sun; in both cases, separate dark absorption lines are observed against a rather bright background. There is nothing unexpected in this, since the radiation of galaxies is the radiation of billions of their constituent stars, more or less similar to the Sun. Careful study of the spectra of galaxies many years ago led to one discovery of fundamental importance. The fact is that by the nature of the shift of the wavelength of any spectral line with respect to the laboratory standard, one can determine the speed of the emitting source along the line of sight. In other words, it is possible to establish with what speed the source is approaching or receding.
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 in galaxies (with the exception of a few closest to us) the spectral lines are always shifted to the long-wavelength part of the spectrum (the "redshift" of the lines), and the magnitude of this shift is the greater, the further the galaxy is from us. 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 receding velocity of the Cygnus A radio galaxy found from the redshift is close to 17,000 km/s. Twenty-five years ago, the record belonged to the very faint (in optical rays of magnitude 20) radio galaxy ZC 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! The radio galaxy 3C 295 is at a distance from us that light travels in 5 billion years. Thus, astronomers studied the light that was emitted when the Sun and planets formed, and maybe even "a little" earlier ... Since then, even more distant objects have been discovered (ch. 6). The reasons for the expansion of a system consisting of a huge number of galaxies, we will not touch here. This complex question is the subject of modern cosmology. However, the very fact of the expansion of the universe has great importance to analyze the development of life in it (chap. 7). Superimposed on the general expansion of the system of galaxies are the erratic speeds of individual galaxies, usually equal to several hundred kilometers per second. That is why the galaxies closest to us do not exhibit a systematic redshift. After all, the velocities of random (so-called "peculiar") motions for these galaxies are greater than the regular redshift velocity. The latter increases as the galaxies move away by about 50 km/s, for every million parsecs. Therefore, for galaxies whose distances do not exceed a few 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 the 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 included in a large cluster of galaxies, the center of which is located in that part of the sky on which the constellation Virgo is projected. This cluster has several thousand members and is one of the largest. On fig. Figure 8 shows a photograph of the famous cluster of galaxies in the constellation of the Northern Crown, numbering hundreds of galaxies. In the space between clusters, the density of galaxies is ten times less than inside clusters.
Rice. 8. A cluster of galaxies in the constellation of the Northern Crown
Attention is drawn to the difference between clusters of stars that form galaxies and clusters of galaxies. In the first case, the distances between cluster members are huge compared to the sizes of stars, while the average distances between galaxies in galaxy clusters are only several times greater than the sizes of galaxies. On the other hand, the number of galaxies in clusters cannot be compared with the number of stars in galaxies. If we consider the totality 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 |
|
|
Galaxy formation (z~10) |
|
|
Formation of the solar system |
|
|
Earth formation |
|
|
Origin of life on earth |
|
|
The formation of the oldest rocks on Earth |
|
|
The emergence of bacteria and blue-green algae |
|
|
The emergence of photosynthesis |
|
|
The first cells with a nucleus |
|
| Sunday | Monday | Tuesday | Wednesday | Thursday | Friday | Saturday |
| The emergence of an oxygen atmosphere on Earth | Powerful volcanic activity on Mars | |||||
| First worms | Ocean Plankton Trilobites | Ordovician First fish | Silurus Plants colonize land | |||
| Devonian First insects Animals colonize land | The first amphibians and winged insects | Carbon First trees First reptiles | Permian First dinosaurs | Beginning of the Mesozoic | Triassic First mammals | Yura 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 "kilometer 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: the speed of 1 pc in 1 million years is almost equal to the speed of 1 km/s. We leave it to the reader to verify this.
- ***** The flux of radiation from stars is measured by the so-called "magnitudes". By definition, the flux from a star of (i + 1)th magnitude is 2.512 times less than from a star i-th value. Stars fainter than 6th magnitude are not visible to the naked eye. The brightest stars have a negative magnitude (for example, in Sirius it is -1.5).
Alexander Zakharov ( [email protected])“Construction” of the Universe
(When I wrote this article and sent it to Alexander Ter-Oganesyants, it turned out that he was actively corresponding with Evgraf Duluman and
letters . Also (it turns out!) An article by Yuri Shelyazhenko was published “Everyone is free to believe that he is an atheist ". The theme of the origin of the universe is popular J )“The most diverse substances, combined in a thousand ways, continuously receive and communicate various movements to each other. Various properties of these substances, their various combinations, their various modes of action, which are necessary consequences of this, constitute for us the essence of everything that exists, and from the difference of these essences depend the various orders, categories or systems occupied by these substances, the totality of which constitutes what we call nature.
Paul Henri Holbach (1723 - 1789), "The System of Nature".
I found a curious article by Alexander Ter-Oganesyants "The Structure of the Universe". The author presents his view on the structure of the Universe and, in my opinion, quite interesting. First he writes:
I ask you to find errors in my reasoning about the structure of the Universe.”
I would not like to “look for errors” in the author’s reasoning (for this you need to be someone like a god, and God himself is stubbornly silent on this topic J ), most likely I would like to express my vision of this difficult issue as a discussion of his article. I would not call my article critical, because. the things about which in question- these are hypotheses and neither I, nor the respected Alexander Karlovich, I think, are able to confirm or refute my own or someone else's point of view. J With my article, I only want to discuss together with the author on the structure of the Universe (also quite schematically), so to speak, to take part in the “construction of the Universe” as an integral picture in the human mind. Well, along the way, express your opinion about his hypothesis.
Here is what he writes:
“The universe is infinite in space and time. Only by accepting this postulate, we can get rid of the well-known questions: What's next? and what happened before? At the same time, it should be borne in mind that what we often call the Universe is in fact our Metagalaxy, that is, that part of the Universe that is subject to our research.”
In my opinion, the infinity of the Universe in space and time is, of course, a kind of postulate, but I would say that it is introduced not to cut off “objectionable” questions, but because this is the least absurd assumption, because all other options “in the limit” have more questions than answers. And you need to be based on something. And indeed, do not forget about the concept of the Universe:
The Universe is the entire existing material world, unlimited in time and space and infinitely diverse in the forms that matter takes in the process of its development. The universe studied by astronomy is a part of the material world, which is available for research by astronomical means, corresponding to achieved level development of science (often this part of the universe is called Metagalaxy ).
So, I think, for example, that we can talk about the “origin of the Universe” in relation to the Metagalaxy, but this does not apply to the Universe by definition - it has always existed. And “our Metagalaxy” once arose and is still developing according to its own laws. And I think it will be impossible to answer questions about what happened before our metagalaxy for a long time (and maybe infinitely long).
There are two primary principles in the Universe, or, if you like, two objective realities: Matter and Consciousness. Ask so-called. “the main question of philosophy” - what comes first? - in fact, it makes no sense, since Matter and Consciousness have existed and will exist forever. It's like asking which came first, the chicken or the egg? Both Matter and Consciousness obey their own conservation laws: they do not arise from nothing and do not turn into nothing, but only pass from one form to another. Forms of existence and Consciousness and Matter in infinite universe, of course, there is an infinite set.
It seems to me that the author transparently introduced another postulate for himself: “ There are two primary principles in the Universe, or, if you like, two objective realities: Matter and Consciousness”. For me, a very dubious statement, tk. I accept the following definition of matter:
Matter is substance; the substratum (basis) of all properties, connections and forms of movement that really exist in the world; an infinite set of all objects and systems existing in the world. An integral attribute of matter is movement; Matter is characterized by self-development, the transformation of some states into others. The universal objective forms of the existence of matter are space and time. Special types material systems- living matter (a set of organisms capable of self-reproduction) and socially organized matter (society).
And it seems to me that “Consciousness” in the scheme proposed by the author is a necessary (for his hypothesis), but at the same time “superfluous” entity (i.e., for an explanation, you can do without it). J And what is meant by Consciousness? For example, here is the definition from ES:
Consciousness is one of the basic concepts of philosophy, sociology, denoting the human ability to ideally reproduce reality in thinking. … Consciousness appears in two forms: individual (personal) and public. Public consciousness is a reflection of social life; forms public consciousness Keywords: science, philosophy, art, morality, religion, politics, law.
Further, of course, the author comments on what is Consciousness in his understanding, but, in my deep conviction, his interpretation is incorrect, and besides, it also has a certain religious imprint (although the author is an atheist J ).
The main property of Matter is expressed in the second law of thermodynamics: “In a closed physical system, only the growth of entropy is possible.” Entropy is a measure of the disorder of a system. Matter always strives for disorder, destruction, chaos.
If you philosophize. I would not call the property of matter the desire for disorder, destruction, chaos. Well, I consider the application of the word “destruction” to matter (in general terms), to put it mildly, inappropriate (there is, after all, the concept of “structure” and “transition”). In addition, the author completely misses an important context: “In closed physical system…”, although it is likely that the isolation of “our metagalaxy” takes place if we consider it from the point of view of a person, as an observer and an object subject to the laws of the metagalaxy itself, located in it, i.e. it turns out a kind of closed space of action of laws and matter has the ability to move from one specific type to another specific type (and all this is “suspended” in the absolute emptiness J ). We cannot exclude the possibility that “our metagalaxy” may have “regions of transition” to other spaces with different laws. Why not? I have a phrase: "If you can change the laws of nature, then nature has laws for changing the laws of nature." J
The law (one of many) of the existence of matter (“ does not arise from nothing and does not turn into nothing”) in my opinion, in my hypothesis, is redundant (because of the word “nothing”), because if we talk about emptiness / vacuum, etc. entities of “nothing”, then I would say that, for example, vacuum (something like interstellar space or physical vacuum or the like) is also a form of existence of matter. If for us, as researchers / observers, absolute vacuum is “nothing” / “emptiness”, then this only means that this type of matter is an absolutely unexplored area or we simply don’t see anything “there” that we could see , removed and got a vacuum J I.e. matter is, in my hypothesis, an absolutely broad concept, and I see no reason to limit the forms of matter and their properties to some invented framework. Every “nothing” is something! J (For lovers of analogies: if you look through pure clear glass- you don’t notice it, it’s as if it doesn’t exist, but it’s worth spraying water on its surface ... J)
The main property of Consciousness is the desire for creation, order and harmony. There is a continuous and eternal struggle between Matter and Consciousness, which is the basis for the development of the Universe.
The words "order", "harmony" are subjective assessments. There is a phrase "The law of the universe." From this Law follows, in general, all the "harmony" and "order". There would be another Law (the sum of laws) - there would be a different order and harmony. Order is the observance of a certain rule, a law. Harmony is a broader term, but also from “this” area.
The word “creation” somehow immediately implies the presence of personal characteristics, which in turn steadily leads us to the concept of “god”. J But this is still “written with a pitchfork on the water”, and the main thing is that it seems to me very strange to oppose Matter to Consciousness. Just the same fight between good and evil! “Good will surely overcome Evil. Put him on his knees and brutally kill” J
On Earth, Consciousness won a local victory, and the course of development of the system, natural for Matter, was disturbed: life appeared on Earth, and then intelligent life.
To put it mildly, I would be careful not to divide living matter into rational and non-intelligent, rather, it is more intelligent and less intelligent.
The human mind - one of the forms of the existence of Consciousness - is inextricably linked with the material part of a person - his body - one of the forms of the existence of Matter. The mind and body are in constant struggle, which is the basis for the development of human civilization. At the moment of conception, like a bodily embryo - a fertilized egg - a consciousness embryo appears, composed of the elements of the mind of the father and mother and developing according to its own laws. After the death of a person, like a body, the mind disintegrates into elementary components, which dissolve in the world Consciousness.
It is beautiful, of course, but in order to reach this “beauty” it is necessary to make quite a lot of “postulates”. J I think that “in such a case” one should not look for beauty, but consistency (at least).
5. The discovery in the mid-1920s by the American astronomer Hubble of the law of “recession of galaxies” led to the emergence of the “Big Bang” theory, according to which our entire Metagalaxy (galaxies, stars, planets, and other objects) was formed as a result of a “flash” of supersubstance, compressed in a very limited amount of space. Some religious philosophers saw in this theory a confirmation of the well-known Bible text about the creation of the world out of chaos. I believe that in reality the situation was exactly the opposite. And the point, of course, is not the gigantic discrepancy between the timing of the birth of the Universe: 7.5 thousand years ago according to the Bible and 18 billion years according to the Big Bang theory.
It seems to me that before the Big Bang, the Universe was a very harmonious and balanced system in which Consciousness reigned, and Matter, like a genie, was driven into a bottle. Probably, at some point the Consciousness lost control over Matter, or the internal tension “in the bottle” reached a critical level. As a result, the global liberation of Matter took place, in comparison with which a hypothetical thermonuclear catastrophe on Earth looks like a mosquito bite.
I don't know how reasonable it is to single out the fact of the emergence of "our metagalaxy" as "out of the ordinary". My opinion is that in this way there was a rebirth - the transition of one type of matter into another. Who knows, maybe it was quite a “natural process”. Why is regular in quotation marks? I just think that before the emergence of “our metagalaxy” with its laws of existence of a certain number of forms of matter that we can explore, there were other laws and other forms of matter and not necessarily those that we define as inherent in “our metagalaxy”. Here it is necessary to separate in some way. More formally and in other words, I express this in the form of a rhetorical question: “Is it correct to try to describe what was before the emergence of our universe by the laws of the existence of our universe?” J (the Universe means “our metagalaxy”).
Why do I emphasize that the metagalaxy is precisely “ours”? I see no reason not to admit (in my interpretation of the existence of the Universe) that it is possible (I would not even be afraid to say “very likely”) the existence of other formations in the form of metagalaxies that have the same structure, internal laws, and also other forms of metagalaxies with other laws, the number of forms of matter, so to speak, participating in the arrangement of such education, and living matter, for which some ten-dimensional space is a “native home”. J And this living matter is, in a way, the result of the process of development of certain types of matter determined by the laws of this particular metagalaxy. Well, speaking of living matter and consciousness: well, being determines consciousness! And matter gives birth to it. (BUT after and vice versa… J )
However, in the eternal struggle of Consciousness and Matter, it is remarkable that not a single victory of any side, no matter how global it may seem, is actually final. It is quite probable that in some 5-10 billion years the "recession of galaxies" will end and the reverse process will begin. In the meantime, Consciousness is waging war with Matter in all the vast expanses of the Metagalaxy, gaining local victories in some places (for example, on Earth).
What awaits “our metagalaxy” is still an open question, but I think it will be solved in the future… in the distant future J .
All this, of course, is very schematic, and I would be glad to discuss with you more about the structure of the Universe. I would be very grateful if you answer me.
Well, here is the answer. J I also have a lot of schematics, but as M. Lomonosov said: “Nature is very simple. Whatever contradicts this must be rejected.” And of course, “simplicity” is a relative term. J
In conclusion, I want to give one more, in my opinion, an interesting statement regarding the relationship between man and Nature (metagalaxy, universe). I think in the context of the “battles” between Consciousness and Matter, it would be appropriate for the author to cite it:
“Nature never fights with a person, this is a vulgar religious slander against her, she is not so smart as to fight, she doesn’t care ... Nature cannot contradict a person if a person does not contradict her laws ...”
Alexander Ivanovich Herzen (1812 - 1870), "Collected Works".
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What do we know about the universe, what is the cosmos like? The Universe is a boundless world that is difficult to comprehend by the human mind, which seems unreal and non-material. In fact, we are surrounded by matter, boundless in space and time, capable of taking various forms. In order to try to understand the true scale of outer space, how the Universe works, the structure of the universe and the processes of evolution, we will need to cross the threshold of our own worldview, look at the world around us from a different angle, from the inside.
A look at the vast expanses of space from Earth
The Formation of the Universe: First Steps
The space that we observe through telescopes is only a part of the stellar Universe, the so-called Megagalaxy. The parameters of the Hubble cosmological horizon are colossal - 15-20 billion light years. These data are approximate, since in the process of evolution the Universe is constantly expanding. The expansion of the universe occurs through the spread chemical elements and relic radiation. The structure of the universe is constantly changing. In space, clusters of galaxies arise, objects and bodies of the Universe are billions of stars that form elements of the near space - star systems with planets and satellites.
Where is the beginning? How did the universe come into existence? Presumably the age of the Universe is 20 billion years. It is possible that hot and dense protomatter became the source of cosmic matter, the cluster of which exploded at a certain moment. The smallest particles formed as a result of the explosion scattered in all directions, and continue to move away from the epicenter in our time. The Big Bang theory, which now dominates the scientific community, is the most accurate description of the process of formation of the Universe. The substance that arose as a result of a cosmic cataclysm was a heterogeneous mass consisting of the smallest unstable particles that, colliding and scattering, began to interact with each other.
The Big Bang is a theory of the origin of the universe, explaining its formation. According to this theory, initially there was a certain amount of matter, which, as a result of certain processes, exploded with colossal force, scattering a mass of mother into the surrounding space.
Some time later, according to cosmic standards - an instant, according to earthly chronology - millions of years, the stage of materialization of space has come. What is the universe made of? Dispersed matter began to concentrate into clots, large and small, in the place of which the first elements of the Universe subsequently began to appear, huge gas masses - the nursery of future stars. In most cases, the process of formation of material objects in the Universe is explained by the laws of physics and thermodynamics, however, there are a number of points that cannot yet be explained. For example, why in one part of space the expanding substance is concentrated more, while in another part of the universe the matter is very rarefied. Answers to these questions can be obtained only when the mechanism of formation of space objects, large and small, becomes clear.
Now the process of formation of the Universe is explained by the action of the laws of the Universe. Gravitational instability and energy in different areas triggered the formation of protostars, which in turn, under the influence of centrifugal forces and gravity, formed galaxies. In other words, while the matter continued and continues to expand, compression processes began under the influence of gravitational forces. Particles of gas clouds began to concentrate around the imaginary center, eventually forming a new seal. The building material in this gigantic construction site is molecular hydrogen and helium.
The chemical elements of the Universe are the primary building material from which the formation of the objects of the Universe subsequently proceeded.
Further, the law of thermodynamics begins to operate, the processes of decay and ionization are activated. Molecules of hydrogen and helium break up into atoms, from which, under the influence of gravitational forces, the core of a protostar is formed. These processes are the laws of the Universe and have taken the form of a chain reaction, taking place in all distant corners of the Universe, filling the universe with billions, hundreds of billions of stars.
Evolution of the Universe: Highlights
Today, in scientific circles, there is a hypothesis about the cyclicity of the states from which the history of the Universe is woven. Having arisen as a result of the explosion of protomatter, gas accumulations became a nursery for stars, which in turn formed numerous galaxies. However, having reached a certain phase, matter in the Universe begins to strive for its original, concentrated state, i.e. The explosion and the subsequent expansion of matter in space are followed by compression and a return to a superdense state, to the starting point. Subsequently, everything repeats itself, the birth is followed by the final, and so on for many billions of years, ad infinitum.
The beginning and end of the universe in accordance with the cyclical nature of the evolution of the universe
However, having omitted the topic of the formation of the Universe, which remains an open question, we should move on to the structure of the universe. Back in the 30s of the XX century, it became clear that outer space is divided into regions - galaxies, which are huge formations, each with its own stellar population. However, galaxies are not static objects. The speed of expansion of galaxies from the imaginary center of the Universe is constantly changing, as evidenced by the convergence of some and the removal of others from each other.
All of these processes, from the point of view of the duration of earthly life, last very slowly. From the point of view of science and these hypotheses, all evolutionary processes occur rapidly. Conventionally, the evolution of the Universe can be divided into four stages - eras:
- hadron era;
- lepton era;
- photon era;
- stellar era.
Cosmic time scale and the evolution of the Universe, according to which the appearance of space objects can be explained
At the first stage, all matter was concentrated in one large nuclear drop, consisting of particles and antiparticles, combined into groups - hadrons (protons and neutrons). The ratio of particles and antiparticles is approximately 1:1.1. Then comes the process of annihilation of particles and antiparticles. The remaining protons and neutrons are the building material from which the Universe is formed. The duration of the hadron era is negligible, only 0.0001 seconds - the period of the explosive reaction.
Further, after 100 seconds, the process of synthesis of elements begins. At a temperature of a billion degrees, hydrogen and helium molecules are formed in the process of nuclear fusion. All this time, the substance continues to expand in space.
From this moment begins a long, from 300 thousand to 700 thousand years, stage of recombination of nuclei and electrons, forming hydrogen and helium atoms. In this case, a decrease in the temperature of the substance is observed, and the intensity of radiation decreases. The universe becomes transparent. Hydrogen and helium formed in colossal quantities, under the influence of gravitational forces, turns the primary Universe into a giant construction site. After millions of years, the stellar era begins - which is the process of formation of protostars and the first protogalaxies.
This division of evolution into stages fits into the model of the hot Universe, which explains many processes. The true causes of the Big Bang, the mechanism of the expansion of matter remain unexplained.
The structure and structure of the universe
With the formation of hydrogen gas, the stellar era of the evolution of the Universe begins. Hydrogen under the influence of gravity accumulates in huge accumulations, clots. The mass and density of such clusters are colossal, hundreds of thousands of times greater than the mass of the formed galaxy itself. The uneven distribution of hydrogen, observed at the initial stage of the formation of the universe, explains the differences in the sizes of the formed galaxies. Where there should have been a maximum accumulation of hydrogen gas, megagalaxies formed. Where the concentration of hydrogen was negligible, smaller galaxies appeared, like our stellar home, the Milky Way.
The version according to which the Universe is a start-end point around which galaxies revolve at different stages of development
From this moment on, the Universe receives the first formations with clear boundaries and physical parameters. These are no longer nebulae, accumulations of stellar gas and cosmic dust (explosion products), protoclusters of stellar matter. These are star countries, the area of \u200b\u200bwhich is huge in terms of the human mind. The universe becomes full of interesting cosmic phenomena.
From the point of view of scientific justifications and the modern model of the Universe, galaxies were first formed as a result of the action of gravitational forces. Matter was transformed into a colossal universal whirlpool. Centripetal processes ensured the subsequent fragmentation of gas clouds into clusters, which became the birthplace of the first stars. Protogalaxies with a fast rotation period turned into spiral galaxies over time. Where the rotation was slow, and the process of compression of matter was mainly observed, irregular galaxies were formed, more often elliptical. Against this background, more grandiose processes took place in the Universe - the formation of superclusters of galaxies, which closely touch each other with their edges.
Superclusters are numerous groups of galaxies and clusters of galaxies in the large-scale structure of the Universe. Within 1 billion St. years there are about 100 superclusters
From that moment it became clear that the Universe is a huge map, where the continents are clusters of galaxies, and the countries are megagalaxies and galaxies that formed billions of years ago. Each of the formations consists of a cluster of stars, nebulae, accumulations of interstellar gas and dust. However, all this population is only 1% of the total volume of universal formations. The main mass and volume of galaxies is occupied by dark matter, the nature of which is not possible to find out.
Diversity of the Universe: classes of galaxies
Through the efforts of the American astrophysicist Edwin Hubble, we now have the boundaries of the universe and a clear classification of the galaxies that inhabit it. The classification was based on the structural features of these giant formations. Why do galaxies have different shape? The answer to this and many other questions is given by the Hubble classification, according to which the Universe consists of galaxies of the following classes:
- spiral;
- elliptical;
- irregular galaxies.
The former include the most common formations that fill the universe. Characteristic features of spiral galaxies are the presence of a clearly defined spiral that rotates around a bright nucleus or tends to a galactic bridge. Spiral galaxies with a core are denoted by the symbols S, while objects with a central bar have the designation already SB. This class also includes our Milky Way galaxy, in the center of which the core is separated by a luminous bar.
A typical spiral galaxy. In the center, a core with a bridge from the ends of which spiral arms emanate is clearly visible.
Similar formations are scattered throughout the universe. The nearest spiral galaxy to us, Andromeda, is a giant that is rapidly approaching milky way. The largest representative of this class known to us is the giant galaxy NGC 6872. The diameter of the galactic disk of this monster is approximately 522 thousand light years. This object is located at a distance of 212 million light years from our galaxy.
The next common class of galactic formations are elliptical galaxies. Their designation in accordance with the Hubble classification is the letter E (elliptical). In shape, these formations are ellipsoids. Despite the fact that there are a lot of similar objects in the Universe, elliptical galaxies are not very expressive. They consist mainly of smooth ellipses that are filled with star clusters. Unlike galactic spirals, ellipses do not contain accumulations of interstellar gas and cosmic dust, which are the main optical effects of visualizing such objects.
A typical representative of this class, known today, is an elliptical ring nebula in the constellation Lyra. This object is located at a distance of 2100 light years from Earth.
View of the elliptical galaxy Centaurus A through the CFHT telescope
The last class of galactic objects that populate the universe are irregular or irregular galaxies. The Hubble classification designation is the Latin character I. The main feature is an irregular shape. In other words, such objects do not have clear symmetrical shapes and a characteristic pattern. In its form, such a galaxy resembles a picture of universal chaos, where star clusters alternate with clouds of gas and cosmic dust. On the scale of the universe, irregular galaxies are a frequent phenomenon.
In turn, irregular galaxies are divided into two subtypes:
- Irregular galaxies of subtype I have a complex irregular structure, a high dense surface, which is distinguished by brightness. Often such a chaotic shape of irregular galaxies is the result of collapsed spirals. A typical example of such a galaxy is the Large and Small Magellanic Clouds;
- Irregular subtype II galaxies have a low surface, a chaotic shape, and are not very bright. Due to the decrease in brightness, such formations are difficult to detect in the vastness of the universe.
The Large Magellanic Cloud is the closest irregular galaxy to us. Both formations, in turn, are satellites of the Milky Way and may soon (in 1-2 billion years) be absorbed by a larger object.
The irregular galaxy The Large Magellanic Cloud is a satellite of our Milky Way galaxy.
Despite the fact that Edwin Hubble quite accurately placed the galaxies into classes, this classification is not ideal. We could achieve more results if we included Einstein's theory of relativity in the process of knowing the Universe. The universe is represented by a wealth of various forms and structures, each of which has its own characteristic properties and features. Recently, astronomers have been able to detect new galactic formations that are described as intermediate objects between spiral and elliptical galaxies.
The Milky Way is the most known part of the universe to us.
Two spiral branches, symmetrically located around the center, make up the main body of the galaxy. Spirals, in turn, consist of sleeves that smoothly flow into each other. At the junction of the arms of Sagittarius and Cygnus, our Sun is located, located from the center of the Milky Way galaxy at a distance of 2.62 10¹⁷ km. The spirals and arms of spiral galaxies are clusters of stars that increase in density as they approach the galactic center. The rest of the mass and volume of galactic spirals is dark matter, and only a small part is accounted for by interstellar gas and cosmic dust.
The position of the Sun in the arms of the Milky Way, the place of our galaxy in the Universe
The thickness of the spirals is approximately 2 thousand light years. This whole layer cake is in constant motion, rotating at a tremendous speed of 200-300 km / s. The closer to the center of the galaxy, the higher the rotation speed. It will take the sun and our solar system 250 million years to make a complete revolution around the center of the Milky Way.
Our galaxy is made up of a trillion stars, large and small, superheavy and medium-sized. The densest cluster of stars in the Milky Way is the Sagittarius arm. It is in this region that the maximum brightness of our galaxy is observed. The opposite part of the galactic circle, on the contrary, is less bright and poorly distinguishable by visual observation.
The central part of the Milky Way is represented by a core, the dimensions of which are presumably 1000-2000 parsecs. In this brightest region of the galaxy, the maximum number of stars is concentrated, which have different classes, their own paths of development and evolution. Basically, these are old superheavy stars that are at the final stage main sequence. Confirmation of the presence of the aging center of the Milky Way galaxy is the presence in this region a large number neutron stars and black holes. Indeed, the center of the spiral disk of any spiral galaxy is a supermassive black hole, which, like a giant vacuum cleaner, sucks in celestial objects and real matter.
The supermassive black hole in the central part of the Milky Way is the place where all galactic objects die.
As for star clusters, scientists today managed to classify two types of clusters: spherical and open. In addition to star clusters, the spirals and arms of the Milky Way, like any other spiral galaxy, are composed of scattered matter and dark energy. Being a consequence of the Big Bang, matter is in a highly rarefied state, which is represented by rarefied interstellar gas and dust particles. The visible part of matter is represented by nebulae, which in turn are divided into two types: planetary and diffuse nebulae. The visible part of the spectrum of nebulae is explained by the refraction of the light of stars, which radiate light inside the spiral in all directions.
It is in this cosmic soup that our solar system exists. No we're not the only ones in this wide world. Like the Sun, many stars have their own planetary systems. The whole question is how to detect distant planets, if the distances even within our galaxy exceed the duration of the existence of any intelligent civilization. Time in the Universe is measured by other criteria. Planets with their satellites are the smallest objects in the Universe. The number of such objects is incalculable. Each of those stars that are in the visible range may have their own star systems. It is in our power to see only the closest existing planets to us. What happens in the neighborhood, what worlds exist in other arms of the Milky Way, and what planets exist in other galaxies, remains a mystery.
Kepler-16 b is an exoplanet around the double star Kepler-16 in the constellation Cygnus
Conclusion
Having only a superficial idea of how the Universe appeared and how it is evolving, a person has taken only a small step towards comprehending and comprehending the scale of the universe. The grandiose dimensions and scales that scientists have to deal with today indicate that human civilization is only a moment in this bundle of matter, space and time.
Model of the Universe in accordance with the concept of the presence of matter in space, taking into account time
The study of the universe goes from Copernicus to the present day. At first, scientists started from the heliocentric model. In fact, it turned out that the cosmos does not have a real center and all rotation, movement and movement occurs according to the laws of the Universe. Despite the fact that there is a scientific explanation for the ongoing processes, universal objects are divided into classes, types and types, no body in space is similar to another. The sizes of celestial bodies are approximate, as well as their mass. The location of galaxies, stars and planets is conditional. The point is that there is no coordinate system in the Universe. Observing space, we make a projection on the entire visible horizon, considering our Earth as a zero reference point. In fact, we are only a microscopic particle, lost in the endless expanses of the Universe.
The Universe is a substance in which all objects exist in close relation to space and time
Similarly to binding to dimensions, time in the Universe should be considered as the main component. The origin and age of space objects allows you to make a picture of the birth of the world, to highlight the stages of the evolution of the universe. The system we are dealing with is closely tied to time frames. All processes occurring in space have cycles - the beginning, formation, transformation and final, accompanied by the death of a material object and the transition of matter to another state.
The main elements of the structure of the universe: galaxies, stars, planets
Galaxies (from the Greek. Milky, milky) - systems of billions of stars revolving around the center of the galaxy and connected by mutual gravity and common origin,
planets- bodies that do not emit energy, with a complex internal structure.
The most common celestial body in the observable universe are the stars.
According to modern concepts A star is a gas-plasma object in which thermonuclear fusion occurs at temperatures above 10 million deg. TO.
The high luminosity of stars, maintained for a long time, indicates the release of huge amounts of energy in them.
The main reasons for the high luminosity of stars
- gravitational contraction , leading to the release of gravitational energy (typical for young stars)
- thermonuclear reactions , as a result of which the nuclei of heavier elements are synthesized from the nuclei of light elements and a large amount of energy is released.
Our Sun is a slowly burning hydrogen bomb.
Atoms of elements lighter than iron are formed as a result of thermonuclear reactions inside stars. Heavier than iron in supernova explosions.
The evolution of stars is a change in physical characteristics, internal structure and chemical composition stars over time.
The process of formation of cosmic bodies from a rarefied gas and gas-dust environment under the influence of gravitational forces is called gravitational condensation
protostar- a dense fragment of a molecular cloud, in which the temperatures necessary for the start of thermonuclear reactions have not yet been reached, i.e. turning a cloud into a star.
The end of a star's evolution is determined by its mass.
The final stage in the evolution of a star of medium and low mass (less than 3-4 solar masses) is a white dwarf .
The evolution of stars of greater mass leads to the formation of neutron stars or black holes.
As a result of gravitational collapse, a powerful explosion of a star occurs, accompanied by the release of colossal energy in the form of electromagnetic radiation and the release into the surrounding space of substances representing the chemical elements of the entire periodic table (the first observations of a supernova explosion were made by Chinese and Japanese astronomers in 1054).
Stars act as a kind of forge of atoms.
According to cosmological models, the distribution of chemical elements throughout the universe occurs as a result of explosions of supernovae.
The solar system is part of the universe.
The geocentric system of the world is an idea that existed in antiquity (Aristotle and Ptolemy), according to which the Earth rests motionlessly in the center of the world, and all heavenly bodies move around it.
In the first half of the 16th century - 17 scientists N. Copernicus, G. Galileo, J. Bruno developed the heliocentric system of the world - the doctrine according to which the Earth, like other planets, revolves around the Sun and, in addition, rotates around its axis.
solar system - planetary system milky way, which includes: the Sun, eight classical planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune), several dwarf planets (Pluto, Xena, etc.), planetary satellites, comets, meteoroids, cosmic dust .
The central body of the solar system, in which the vast majority of its mass (about 99.9%) is concentrated, is the Sun.
According to modern concepts, the solar system was formed as a result of the compression of a gas and dust cloud approximately 5 billion years ago.
It is believed that the evolution of the protoplanetary disk took place over 1 million years. There was an adhesion of particles in the central part of this disk, which subsequently led to the formation of clusters of particles, initially small, then larger.
In the 40s of the 20th century. Academician O.Yu.Schmidt put forward the generally accepted hypothesis about the formation of the Earth and other planets from cold solid pre-planetary bodies. These bodies are called planetesimals.
This concept is confirmed by the results of computer simulations.
However, there are other models as well.
Sufficiently accurate data on the age of the Earth are obtained by analyzing the radioactive transformations of the Earth's elements and meteorites.
CONCEPTUAL CONTENT OF EARTH SCIENCES.
The structure of the earth.
Earth is the third planet in the solar system.
The earth represents solid, surrounded by water and gas shells - the hydrosphere and atmosphere.
The earth is not a perfect sphere. It is flattened at the poles and expanded towards the equator. The shape of the Earth is a spheroid or ellipsoid of revolution. With great accuracy, the shape of the Earth was determined only in the 20th century. with the help of devices installed on artificial satellites.
The average radius of the Earth is 6370 km.
The surface area of the Earth is 510 million sq. km. About 71% of the Earth's surface is occupied by the World Ocean (361 million km 2), 29% is land (149 million km 2)
Distinguish between internal earth's crust, mantle, core) and external ( hydrosphere, atmosphere)
shells of the earth. The bowels of the Earth are just as inaccessible for direct study as galaxies. The materials that make up the solid Earth are opaque and dense. Direct studies of them are possible only to depths that make up an insignificant part of the Earth's radius (the most deep well about 12 km on the Kola Peninsula).
The problem of the structure of the Earth is solved, mainly only by indirect methods.
The most reliable information about the internal structure of the Earth gives us seismography- registration of seismic vibrations during earthquakes.
Earth's crust - the outer solid shell of the Earth.
Its thickness is uneven: on the continents 30-40 km, under the mountains (Pamir, Andes) - up to 70 km, under the oceans - 5-10 km.
Half of the entire mass of the crust is oxygen (in the bound state).
The geological features of the earth's crust are determined by the combined actions of the atmosphere, hydrosphere, and biosphere on it. The composition of the bark and outer shells is continuously updated.
Mantle (translated from Greek "veil, cloak)
Under the earth's crust, closer to the center of the earth, there is a layer almost 2900 km thick, called the mantle. The mantle is the most powerful shell of the Earth.
Scientists suggest that the mantle consists mainly of silicon compounds.
The mantle exists in the form of two spherical layers - the lower and upper mantle. The thickness of the lower part of the mantle is 2000 km, the upper one is 900 km.
Lithosphere - formed by the earth's crust together with the uppermost solid part of the mantle (about 100 km thick).
Asthenosphere - the lower part of the upper mantle is in a molten state. The lithosphere, as it were, "floats" in it. The asthenosphere contains the foci of volcanoes. The processes occurring in the mantle determine tectonic movement, the formation of magma and volcanic activity.
Earth core. Under the mantle is the core of the earth with a radius of about 3500 km. The core consists of an outer shell in a liquid state (2200 km thick) and an inner solid sub-core (1250 km).
The liquid state of the outer core is associated with ideas about the nature of terrestrial magnetism.
During the transition from the mantle to the core, the physical properties substances, apparently as a result of high pressure. The Earth's core is still a mystery to science. With a certain certainty, we can only talk about its radius and temperature ~ 4000-5000 0 C.
The chemical composition of the core is iron and nickel.
Theory of lithospheric plates.
The influence of internal processes on the evolution of the geological structures of the Earth is currently explained by the theory of lithospheric plates.
According to this theory, the entire lithosphere is divided by narrow active zones - deep faults - into separate rigid blocks floating in the plastic layer of the upper mantle (asthenosphere).
All changes occurring on the surface of the planet are associated with the movement of these plates on it. The largest of the plates are the Antarctic, Australian, South American, Pacific, North American and Eurasian. The number and position of the plates changed from epoch to epoch. Plates can move forward, turn around, collide and diverge. The birth of plates and their retreat back into the mantle takes place in the oceans.
Along the boundaries of the lithospheric plates there are zones of increased tectonic activity (eg the Kuril-Kamchatka island arc).
What is the driving force of "floating continents"? As the data of thermodynamic and seismic measurements show, there are variations in temperature and density inside the mantle, as a result of which the circulation of matter occurs: hot and less dense material rises, cools and, with an increase in density, sinks into the depths. A small temperature difference is enough for the plastic mantle to begin to slowly move and force blocks of the lithosphere to move.
Almost all of these plate movements are now confirmed by direct measurements using high-precision astronomical and satellite geodesy methods. Now their speeds have been measured, which range from a few mm to 10-18 cm per year.
The theory of tectonic lithospheric plates has significantly changed the worldview and ideas about the evolution of our planet. It also has practical aspects. We have a better understanding of the nature of earthquakes and have been able to improve their prediction. Knowing the fault lines of the earth's crust, along which the displacement of the plates occurs, it is possible to observe this displacement. If it slows down or stops, this indicates the likelihood of an approaching seismic shock or a series of such shocks. The theory of lithospheric plates made the distribution of minerals more understandable.
In general, the dimensions of the Earth are constant, due to the geophysical fields acting on the Earth (gravitational, magnetic, electrical and thermal.)
Hydrosphere
The hydrosphere is understood as the totality of all the waters of the Earth, which are in solid, liquid and gaseous states.
This is the ocean fresh water rivers and lakes, glacial and underground waters.
Functions of the Earth's hydrosphere:
- regulates the temperature of the planet,
- ensures the circulation of substances,
- is an integral part of the biosphere.
Atmosphere - a gaseous shell that surrounds the Earth and rotates with it as a whole.
According to the chemical composition, the Earth's atmosphere is a mixture of gases, consisting mainly of nitrogen (78% vol.) and oxygen (21% vol.).
The Earth's atmosphere is divided into layers: troposphere, stratosphere, mesosphere, thermosphere and exosphere.
Troposphere - This is the lower layer of the atmosphere that determines the weather on our planet. Its thickness is 10 (in the polar latitudes) -18 km (in the tropics). Pressure and temperature decrease with altitude, dropping to -55°C.
The troposphere contains over 80% of the mass of the atmosphere and almost all of the water vapor.
Stratosphere- up to 50-55 km in height.
The lower part of the stratosphere has a constant temperature, in the upper part there is an increase in temperature. The stratosphere contains the ozone layer, which absorbs harsh ultraviolet radiation.
The stratosphere is characterized by exceptionally dry air. Processes in the stratosphere practically do not affect the weather.
Mesosphere - a layer lying above the stratosphere at altitudes of 55-85 km.
Thermosphere (ionosphere) is located above the mesosphere at altitudes of approximately 85-800 km from the Earth's surface. The main processes of absorption and conversion of solar ultraviolet and X-ray radiation take place in it.
The ionosphere consists mainly of ionized particles (plasma) that have the ability to reflect short radio waves. In the thermosphere, meteorites slow down and burn up. Thus, the thermosphere performs the function of the protective layer of the Earth, and also allows for long-range radio communications.
The exosphere is the outermost part of the Earth's upper atmosphere with a low concentration of neutral atoms.
CHEMICAL CONCEPTS
Natural science as a science of the phenomena and laws of nature includes one of the most important branches - chemistry.
Chemistry - the science of the composition, internal structure and transformation of substances, as well as the mechanisms of these transformations.
Phenomena that are accompanied by the transformation of one substance into another are called chemical.
The main practical task of chemistry is to obtain substances with desired properties (applied science).
Fundamental science is looking for ways to control the properties of matter, creating theoretical basis chemical knowledge.
There are four main stages in the development of chemistry:
- The doctrine of the composition of matter (since the 17th century).
- Structural chemistry (since the 19th century).
- The doctrine of chemical processes (since the middle of the 20th century).
- Evolutionary chemistry (since 70 years of the XX century).
At the same time, each new stage arose on the basis of the previous one and included it in a transformed form.
Robert Boyle in 1660 gave the definition of a chemical element: x chemical element – this is a simple body, the limit of the chemical decomposition of a substance, passing without change from the composition of one complex body to the composition of another.
By the middle of the 19th century. scientists already had knowledge about 63 chemical elements. Comparative analysis showed that many elements have similar physical and chemical properties and they can be combined into groups, thereby creating a classification of chemical elements.
DI. Mendeleev in 1869 discovered the periodic law of chemical elements. This is one of the fundamental laws of natural science.
Mendeleev believed that the basis for the classification of chemical elements are their atomic weights. The periodic law in his interpretation was formulated as follows: " The properties of simple bodies, as well as the forms and properties of the compounds of elements, are in a periodic dependence on the value of the atomic weights of the elements».
The physical meaning of the periodic law D.I. Mendeleev opened at creation modern theory structure of the atom and consists in the periodic change in the properties of chemical elements depending on the charge of the nucleus.
Atom
- the smallest structural unit of an element that retains its chemical properties.
The diameter of an atom is equal to several angstroms (A \u003d 10 -8 cm or 10 -10 m)
An atom is made up of a positively charged nuclei and negatively charged electron shell.
atom nucleus consists of particles of two types: positively charged protons and uncharged neutrons.
Chemical element A type of atom with the same nuclear charge. In chemical transformations, the atom retains the charge of the nucleus, and, consequently, its individuality. Atoms of new elements cannot be formed in chemical reactions.
To comply with the rule of electroneutrality of atoms, it is necessary that the number of neutrons and protons in an atom be the same. But the number of neutrons in the nucleus of an atom can vary.
isotopes - atoms of the same element, having a different number of neutrons in the nucleus and, accordingly, different masses.
When studying isotopes, it was found that they do not differ in chemical properties, which, as is known, are determined by the charge of the nuclei and do not depend on the mass of the nucleus.
Examples of isotopes: isotopes of uranium - 235 U and 238 U (radioactive - turns into a stable isotope of lead 206 Pb.)
hydrogen isotopes - 1 H - protium (the nucleus consists of one proton)
2 D - deuterium, (the nucleus consists of one proton and one neutron)
3 T - tritium, (the nucleus consists of one proton and two neutrons).
Chlorine-35 and Chlorine-37 are isotopes of chlorine
The variety of objects studied within the framework of chemistry is by no means limited to isotopes and atoms. Chemical elements are combined into more complex systems called chemical compounds.
Chemical compound
- this is a substance consisting of atoms of one or more elements that are combined into particles - molecules, complexes, crystals or other aggregates.
chemical bond
- a bond between atoms in a molecule or molecular compound, resulting from either the transfer of an electron from one atom to another ( ionic), or the socialization of electrons by a pair (or group) of atoms ( covalent).
The development of knowledge about chemical phenomena made it possible to establish that not only its chemical composition, but also the structure of molecules has a great influence on the properties of a substance.
In 1861, the outstanding Russian chemist A.M. Butlerov created and substantiated theory of the chemical structure of organic compounds. The practical significance of this theory was that she gave rise to the development organic synthesis . There was an opportunity for purposeful qualitative transformation of substances, creation of a scheme for the synthesis of any chemical compounds, including previously unknown ones.
To obtain new materials, knowledge about the composition and structure of compounds was clearly not enough. It was also necessary to take into account the conditions chemical reactions which brought chemistry to a qualitatively new level of its development.
The science of the conditions, mechanisms and rates of chemical reactions is called chemical kinetics.
In the 60-70s. 20th century appeared evolutionary chemistry as the highest level of development of chemical knowledge. It is the science of self-organization and self-development. chemical systems. It is based on ideas about the general evolutionary process in the Universe and the selection of chemical elements.
Under evolutionary processes in chemistry understand the processes of spontaneous synthesis of new chemical compounds, which are more complex and highly organized products compared to the original substances.
The beginning of evolutionary chemistry was laid in the development of the theory of biochemical evolution, which explains the origin of life on earth as a result of processes that obey physical and chemical laws.
Evolutionary chemistry is deservedly considered prebiology.
As a result of biochemical evolution from a minimum of chemical elements and chemical compounds, a complex highly organized complex was formed - a biosystem.
The basis of living systems are six elements - organogens: (C, H, O, N, P, S), carbon, hydrogen, oxygen, nitrogen, phosphorus and sulfur. The total weight fraction of these elements in organisms is about 97.4%.
They are followed by 12 more elements that take part in the construction of many physiologically important components of biosystems: sodium, potassium, calcium, magnesium, aluminum, iron, silicon, chlorine, copper, zinc, cobalt, nickel. Their weight fraction in organisms is approximately 1.6%.
New evolutionary chemistry - imitation of living nature. A chemical reactor appears as a kind of living system, which is characterized by self-development and certain behavioral traits.
BIOLOGICAL PICTURE OF THE WORLD
Currently, the most dynamically developing science is biology - the science of life and wildlife.
In the structure of biological knowledge today there are more than 50 special sciences, which is mainly due to the complexity of the main object of biological research - living matter.
The main tasks of biology are to give a scientific definition of life, to point out the fundamental difference between living and non-living things, to find out the specifics of the biological form of the existence of matter.
Life is very complex, diverse, multicomponent and multifunctional. To date, science does not have a sufficiently precise definition of life.
Life represents higher form existence and motion of matter with two characteristic features: self-reproduction and regulated metabolism with the environment.
Fundamental differences between living and non-living:
In material terms: the composition of the living necessarily includes biopolymers - proteins and nucleic acids (DNA and RNA).
Structurally: Living things differ from non-living things in their cellular structure.
Functionally: living bodies are characterized by the reproduction of themselves on the basis of the genetic code.
The most important properties of living systems that distinguish them from inanimate (inert) nature include:
- exchange of matter, energy and information with the environment (open systems);
- self-reproduction ( reproduction);
- complex structure and systemic organization;
- active regulation of its composition and functions (homeostasis);
- maintaining one's own orderliness at the expense of the energy of the external environment;
- mobility;
- irritability;
- adaptability;
- ability to grow and develop;
- molecular chirality (mirror asymmetry).
However, a strictly scientific distinction between living and non-living encounters certain difficulties. Viruses are a transitional form from non-living to living. These are the smallest acellular organisms, 2 orders of magnitude smaller than bacteria. Outside the cells of another organism, they do not possess any of the attributes of a living organism. They have a hereditary apparatus, but they do not have the enzymes necessary for metabolism. Therefore, they can grow and multiply only by penetrating into the cells of the host organism.
Cell possesses all the basic properties of a living system: metabolism and energy (metabolism), reproduction and growth, reactivity and movement. It is the smallest structural and functional unit alive.
The cellular structure of all living organisms, the similarity of the structure of cells and their chemical composition serves as proof of the unity of the organic world.
The diversity of living organisms can be arranged according to the levels of their complexity and specificity of functioning.
The classical levels of modern biology are:
- Molecular genetic(on which the problems of genetics, genetic engineering and biotechnology are solved).
- Cellular(reflecting the features of functioning and specialization of cells, intracellular features).
- ontogenetic(organismic) (all about individual individuals: structure; physiology, behavior).
- population-species(formed by freely interbreeding individuals of the same species).
- biospheric(biogeocenotic) (considering the integrity of all living organisms and the environment, generating the global ecology of the planet).
Each previous level is included in the next, forming a single whole of a living system.
Man has always been interested in how life arose on Earth and all the existing diversity of the animal and plant world.
Therefore, in biology, as in no other science, the methods of analysis, systematization and classification of empirical material have played and are playing an important role.
Like any natural science, biology began to develop as a descriptive (phenomenological) science about the diverse forms, types and relationships of the living world.
Systematics - biological science about the diversity of all existing and extinct organisms, about the relationships and kinship between their various groups (taxa).
The foundations of systematics were laid at the end of the 17th - the first half of the 18th century in the works of J. Ray (1693) and C. Linnaeus (1735).
Evolution
in biology, it represents the development of complex organisms from previous simpler ones. Evolution - historical changes in the hereditary characteristics of organisms, the irreversible historical development of wildlife.
The victory of the evolutionary idea in the 19th century. put an end to science with faith in the divine creation of living beings and man.
The first evolutionary theories were created by two great scientists of the 19th century - J. B. Lamarck and C. Darwin.
The real revolution in biology is associated with the advent of in 1859. Ch. Darwin's theory of evolution, set out by him in the book " Origin of Species by Natural Selection».
evolutionary theory Darwin is built on three postulates: variability, heredity and natural selection.
It is variability that is the first and main link in evolution.
Variability is the ability of organisms to acquire new properties and characteristics.
Darwin identified two forms of variability:
- defined ( adaptive modification). This is the ability of all individuals of the same species, under certain environmental conditions, to respond in the same way to these conditions (climate, soil); not inherited
- indefinite ( mutation). Its character is indirectly connected with changes in external conditions, it is inherited.
Heredity - this is the property of organisms to repeat in a number of generations similar types of metabolism and individual development in general.
Natural selection - is the result of the struggle for existence and means the survival and successful reproduction of the most adapted organisms.
The essence of the evolutionary process is the continuous adaptation of living organisms to various environmental conditions and the emergence of more and more complex organisms.
The emergence of genetics.
Gene - a unit of hereditary material responsible for the formation of any elementary trait, is a section of the DNA molecule.
Chromosomes - these are the structural elements of the cell nucleus, which consist of a DNA molecule and proteins, contain a set of genes with hereditary information contained in them.
In 1944, American biochemists (O. Avery and others) found that the carrier of the property of heredity is DNA (deoxyribonucleic acid) acid)
Since that time, the rapid development of molecular biology began.
Molecular biology - a science that studies the main manifestations of life at the molecular level.
Molecular biology studies how and to what extent the growth and development of organisms, the storage and transmission of hereditary information, the conversion of energy in living cells, and other phenomena are determined by the structure and properties of biologically important molecules (mainly proteins and nucleic acids).
In 1953, the structure of DNA was deciphered (F. Crick, D. Watson).
Rice. DNA double helix
The biological role of DNA is to store and reproduce genetic information, and RNA (ribonucleic acid) in its implementation.
DNA and RNA provide the new organism with information about how it should be built and how it should function.
The property of duplication (replication) of DNA provides the phenomenon of heredity.
Genetic code - this is a single system of "recording" hereditary information inherent in living organisms in the form of a sequence of nucleotides. The unit of the genetic code is a triplet of nucleotides.
Universality of the genetic code - in all organisms on Earth, the same triplets of nucleotides code for the same amino acids
Genome - a set of genes contained in a single set of chromosomes of a given animal or plant cell.
Genotype - the totality of all the genes that are contained in the DNA molecules of a given organism. It is a system that controls the development, structure and vital activity of the body.
Phenotype - the totality of all the characteristics of an organism. The phenotype is the result of the interaction between the genotype and the environment.
gene pool - the totality of genes of a given population, group of individuals or species.
The number of genes in the human body is 20,000-25,000, and the entire genome is more than 3 billion nucleotide pairs (according to the results of the Human Genome Project).
Mutations are changes in the sequence of nucleotides in DNA molecules. Mutations are an extremely rare phenomenon of inaccurate transmission of genetic information, when the chromosomes of a new cell or genes are not quite similar to the old ones.
Modern (synthetic) theory of evolution is a synthesis of genetics and Darwinism. It appeared towards the end of the 1920s. XX century and considers the population as an elementary structure of evolution.
population - a set of individuals of the same species, occupying a certain space for a long time and reproducing itself over a large number of generations.
The hereditary change of a population in any particular direction is carried out under the influence of such evolutionary factors as the mutation process, population waves, isolation, natural selection.
Ontogenesis - a set of transformations that occur in the body from birth to the end of life, i.e., the individual development of the body.
Thus, in the synthetic theory of evolution, it is not ontogeny that comes to the fore, but the development of populations.
Biocenosis - set of cohabiting populations different types living organisms.
Autotrophs - organisms capable of independently synthesizing organic matter from inorganic compounds.
Heterotrophs - organisms that use for food organic substances produced by other organisms.
Autotrophic plants and microorganisms represent the living environment for heterotrophs. A biogeocenotic complex is being formed that can exist for centuries.
Biosphere - space, including the near-Earth atmosphere and the outer shell of the Earth, mastered by living organisms and under the influence of their vital activity. Live nature and its habitat.
Origin of life concepts
The emergence of life on Earth and its biosphere is one of the main problems of modern natural science.
Basic concepts of the origin of life on earth:
1) creationism(lat. creation "creation") life was created by the Creator at a certain time;
2) steady state concept(life has always existed);
3) panspermia(life was brought to Earth from space);
4) abiogenesis- spontaneous generation. According to this theory, life arose and arises repeatedly from inanimate matter. This theory has been circulated in Ancient China, Babylon, Egypt. Aristotle, who is often called the founder of biology, developing the earlier statements of Empedocles on the evolution of living things, adhered to the theory of spontaneous generation of life.
5) biogenesis All living things come from living things. The principle “Living arises only from living things” has received in science the name of the Redi Principle. This is how the concept of biogenesis developed, according to which life can arise only from a previous life. In the middle of the 19th century, L. Pasteur finally refuted the theory of spontaneous generation and proved the validity of the theory of biogenesis.
6) biochemical evolution(the current dominant model). Life arose spontaneously from non-living matter in the specific conditions of the ancient Earth as a result of processes that obey physical and chemical laws.
It should be emphasized that one of the most important differences between the theory of biochemical evolution and the theory of spontaneous (spontaneous) generation is that, according to the theory of evolution, life arose under conditions that are unsuitable for modern biota!
- high temperature, about 400 ° C;
- an atmosphere consisting of water vapor, CO 2 , CH 4 , NH 3 ;
- the presence of sulfur compounds (volcanic activity);
- high electrical activity of the atmosphere;
- ultraviolet radiation from the Sun, which freely reached the lower layers of the atmosphere and the surface of the Earth, since the ozone layer had not yet formed.
Most scientists are of the opinion that on Earth, chemical evolution led to the spontaneous origin of life in the time interval between 4.5 and 3.8 billion years ago. The last hypothesis in the 20s of the XX century was expressed by the Russian scientist A.I. Oparin and Englishman J. Haldane. It formed the basis of modern ideas about the origin of life on Earth.
The hypothesis of Academician A. I. Oparin about the origin of life on Earth (1924) is based on the idea of a gradual complication of the chemical structure and morphological appearance of the precursors of life (probionts) on the way to living organisms.
In the process of the emergence of life on Earth, there are several main stages:
Chemical evolution:
- abiogenic synthesis of low molecular weight organic compounds from inorganic
- synthesis of biopolymers close to nucleic acids and proteins;
- the formation of coacervates (phase-separated systems of organic compounds separated from the external environment by membranes) capable of exchanging matter and energy with the environment. The absorption of metals by coacervates led to the formation of enzymes that accelerate biochemical processes;
- the formation of probionts (precursors of life). Development in the course of evolution in coacervates of the processes of self-regulation, self-reproduction and the ability to carry out the most important life functions - to grow and undergo natural selection.
biological evolution
- The emergence of prokaryotes from probionts
- improvement of the structure and functions of the cell (eukaryotes, multicellular organisms, etc.)
The most difficult part of the problem of the emergence of life is the transition from biopolymers to the first living beings. As a result of the interaction of nucleic acids and proteins, the emergence of membranes with selective permeability, probionts are formed that are capable of self-reproduction. In evolutionary terms, probionts were the predecessors of prokaryotes (non-nuclear unicellular organisms).
Proper biological evolution begins with the formation cellular organization and further follows the path of improving the structure and functions of the cell, the formation of a multicellular organization, the division of the living into the kingdoms of plants, animals, fungi, with their subsequent differentiation into species.
Development of life on earth
catarchean - the geological era of the Earth from its formation to the origin of life (4.6 -3.5 billion years ago).
archaeus - the most ancient geological era, distinguished in the geochronology of the Earth (3.5–2.6 billion years ago).
By the time of the Archaean, the appearance of the first prokaryotes(bacteria and blue-green algae) - organisms that, unlike eukaryotes, do not have a formalized cell nucleus and a typical chromosome apparatus ( hereditary information realized and transmitted through DNA).
The first period of development of the organic world on Earth (archaea) is characterized by the fact that Primary living organisms were anaerobic(lived without oxygen) and heterotrophic those. fed and reproduced from the "organic soup" that arose from inorganic systems.
The transition to photosynthesis and autotrophic nutrition was a great revolutionary upheaval in the evolution of living things (about 3 billion years ago).
It ended about 1.8 billion years ago ( Proterozoic) and led to important transformations on Earth. Soil is formed. In the atmosphere, the content of methane, ammonia, hydrogen decreases, and the accumulation of carbon dioxide and oxygen begins. The primary atmosphere of the Earth was replaced by a secondary, oxygen; an ozone layer appeared, which reduced exposure to ultraviolet rays, and therefore stopped the production of a new "organic soup"; the composition of sea water has changed, it has become less acidic. In this way, modern conditions on Earth were largely created by the vital activity of organisms.
Proterozoic - a huge stage of the historical development of the Earth (2.6 billion - 570 million years ago).
In the most ancient Proterozoic era of the history of the Earth, the initial stage of the emergence of the biosphere is realized. There is practically no reliable information about the biosphere of this era. It seems that in those days only the most primitive forms of life could exist.
Proterozoic(from Greek “primary life”) - a geological era in which unicellular and colonial forms were replaced by multicellular ones. The end of the Proterozoic is sometimes called the "age of jellyfish" - representatives of the intestinal cavities, which were very common at that time.
Paleozoic (from the Greek "ancient life") - geological era (570-230 million years). In the Paleozoic, the land was conquered by multicellular plants and animals.
Mesozoic (from Greek “middle life”) is a geological era (230 - 67 million years)
The Mesozoic era is characterized by the appearance of numerous species of large and giant animals, especially reptiles and reptiles.
Mesozoic is rightly called the era of reptiles.
The geological era in which we live is called Cenozoic.
Cenozoic (from the Greek. " new life”) is the era (67 million years - our time) of flowering plants, insects, birds and mammals.
Human Origins
Homo sapiens - a reasonable person belongs to the order of primates, the suborder of great apes, the family - people.
The first primates appeared about 70 million years ago, the first great apes - 34 million years ago.
Comparison of the DNA of humans and animals allows you to establish the degree of relationship between their organisms. It turned out that the DNA of the gorilla and chimpanzee differs from the human by less than 3%, while the differences from the lower apes exceed 10%.
Currently, most experts believe that the closest predecessor of man are australopithecines- upright mammals. Bone remains of Australopithecus, whose age ranges from 5 to 2.5 million years, were first discovered in 1924 in South Africa. Australopithecus made stone tools, perhaps even used fire, but neither speech nor social structure they didn’t have it - this is a dead end branch of evolution.
Remains found in Africa skillful man"- Zinjantrop, who lived 2 million years ago. He already possessed such human characteristics as upright walking and a noticeable development of the hand. At the same time, the name "skillful" was given to him for the ability to make and use primitive stone tools. Further, the development of modern man can be traced more clearly: Pithecanthropus(1.9-0.65 million years ago); synanthropus(400 thousand years ago), Neanderthal, which appeared according to various sources from 200 to 150 thousand years ago, and, finally, Cro-Magnon, our immediate ancestor, which arose from 200 to 40 thousand years ago.
So the sequence of our ancestors is:
skilled man(Homo habilis)
Homo erectus(Homo erectus)
- Pithecanthropus
- synanthropus
reasonable man(Homo sapiens)
- Neanderthal (dead end branch),
- Cro-Magnon,
It should be noted that anthropogenesis should not be presented as a linear process. It should be borne in mind that evolution is carried out in the process of the constant emergence of new branches (bifurcations), most of which disappear very quickly. In each time period, there are many parallel evolutionary lines descending from a common ancestor.
POST-NON-CLASSICAL (INTEGRAL) NATURAL SCIENCE.
At the end of the 20th and beginning of the 21st century, natural science entered a new historical phase of its development - to the level post-non-classical science(integral natural science).
Modern science is based on the evolutionary-synergetic concept: the main mechanism of the origin and development of the Universe is universal evolutionism and self-organization.
The modern natural-science picture of the world is evolutionary.
The concept and principles of synergetics.
Classical and non-classical natural sciences are united by one common feature: the subject of knowledge for them is simple, closed, isolated, reversible in time) systems.
Distinguish between simple and complex systems.
Simple systems consist of a small number of independent variables, the relationships between which are described by linear equations, amenable to mathematical processing and subject to universal laws.
Complex systems consist of a large number of independent variables and a large number of relationships between them. The larger it is, the more difficult is the study of the object, the derivation of the laws of its functioning. Complex systems are described by non-linear equations that can have multiple solutions. In addition, the more complex the system, the more so-called emergent properties , i.e., properties that its parts do not have, and which are a consequence of the effect of the integrity of the system.
According to the type of interaction with the environment, all systems are divided into:
- open
- closed.
Open systems are real world systems that exchange matter, energy or information with the environment. These include eg. biological and social systems.
Closed systems do not exchange matter, energy, or information with the environment. The concept of a "Closed System" is a high-level abstraction. In reality, no system can be completely isolated from the effects of other systems.
However, it is in relation to closed systems that two principles (laws) of thermodynamics were formulated:
- In a closed system, energy is conserved, although it can take on various forms (the law of conservation of energy).
- The processes occurring in closed systems develop in the direction of increasing entropy and lead to the establishment of an equilibrium state.
In other words, according to the second law of thermodynamics, the energy supply in the Universe is running out, and the entire Universe is inevitably approaching "thermal death".
At the same time, already in the second half of the 19th century, and especially in the 20th century, biology (and, above all, Darwin's theory of evolution) convincingly showed that the evolution of the Universe does not lead to a decrease in the level of organization and impoverishment of the diversity of matter forms.
Rather, on the contrary: the history and evolution of the Universe develop it in the opposite direction - from simple to complex, from lower forms of organization to higher ones, from less organized to more organized.
In the 70s of the 20th century appeared new science « Synergetics”, trying to answer the question of what causes evolution in nature. Development is understood in synergetics as the process of becoming qualitatively new, something that has not yet existed in nature and which is impossible to predict.
Synergetic a- science that studies general principles, underlying all the phenomena of self-organization in complex systems (in physics, chemistry, biology, in technology and theory of computers, in sociology and economics).
The main idea of synergetics - this is the idea of the fundamental possibility of the spontaneous emergence of order and organization from disorder and chaos as a result of the process of self-organization.
The main provisions of the theory of synergetics were developed in the works of G. Haken, G. Nicolis, I. Prigogine.
Basic concepts of synergetics
self-organization - the process of ordering the system, which occurs due to the internal factors of the system itself.
fluctuations - random deviations of the system from some average position, from its natural state.
Bifurcation - the acquisition of a new quality in the movements of a dynamic system with a small change in its parameters.
bifurcation points - turning points of self-organization, critical points of choosing the path of system development.
At present, the concept of self-organization is becoming more widespread not only in the natural sciences, but also in the social and humanitarian sections of the sciences. Most sciences study the processes of evolution of systems and they are forced to analyze the mechanisms of their self-organization.
Self-developing and self-regulating systems include, for example:
- in technology - automatic systems and regulators.
- in the economy - the mechanism of the market of free competition.
- in physiology, the mechanisms of homeostasis that regulate the vital functions of the body: body temperature, respiratory rate, blood pressure, etc.
The whole system of living organisms is based on synergy, i.e. an organized system of life was founded from the initial system of chaos in the process of evolution.
Synergetics is also present in non-living systems. According to this theory, cosmic bodies were formed from the physical vacuum as a result of fluctuation - a temporary deviation from the average. Thus, an organized system of the Universe was created from chaos.
In revealing the mechanisms of self-organization, in addition to nonequilibrium thermodynamics, new ideas and results that appeared in different areas physics and chemistry - in hydrodynamics, laser physics, in the study of autocatalytic reactions and some other phenomena.
The process of self-organization becomes possible under the presence of a number of conditions: the system must be open, non-equilibrium, non-linear, and consist of a large number of elements.
Self-organization of systems proceeds as follows:
- period of smooth evolutionary development, accumulation of fluctuations, bifurcation point (critical state);
- exit from the critical state in a single jump due to the rapid restructuring of the system and transition to a new stable state (dissipative structure) with a greater degree of complexity and order.
- upon completion of the process of self-organization, the system again passes into an evolutionary state.
The principle of global evolutionism - recognition of the impossibility of the existence of all structures born in the universe outside of development, outside of general evolution.
This is the identification of the general laws of nature, linking into a single whole the origin of the Universe (cosmogenesis), the emergence of the solar system and our planet Earth (geogenesis), the emergence of life (biogenesis) and, finally, the emergence of man and society (anthroposociogenesis).
From the point of view of global evolutionism, the entire known history of the Universe as a self-organizing system - from the Big Bang to the emergence of mankind - is presented as a single process with genetic and structural continuity of 4 types of evolution - cosmic, chemical, biological and social.
Global evolutionism reflects the universal connection between inanimate, living and social matter, the fundamental unity of the material world.
Global evolutionism is confirmed by the Big Bang model and non-equilibrium thermodynamics in physics, hypotheses of prebiological evolution in chemistry, the theory of lithospheric plates in geology, evolutionary genetics and biology, as well as other theoretical constructions. In essence, this is one of the forms of implementation of the dialectical principle of development.
Modern concepts of global evolutionism and synergetics (evolutionary-synergetic paradigm) make it possible to describe the development of nature as a successive change of structures born from chaos, temporarily gaining stability, and then again striving for chaotic states.
