Sources of formation of elements in space. The heaviest substance in the universe. The core of a neutron star and its density

Cosmochemistry (from Cosmos and Chemistry

the science of the chemical composition of cosmic bodies, the laws of abundance and distribution chemical elements in the Universe, the processes of combination and migration of atoms during the formation of cosmic matter. The most studied part of Kazakhstan - Geochemistry , K. studies mainly "cold" processes at the level of atomic-molecular interactions of substances, while "hot" nuclear processes in space - the plasma state of matter, nucleogenesis (the process of formation of chemical elements) inside stars, etc. - is mainly dealt with by physics. K. - a new field of knowledge, which received significant development in the second half of the 20th century. mainly due to the success of astronautics. Earlier studies chemical processes in outer space and the composition of cosmic bodies were carried out mainly by spectral analysis(See Spectral analysis) radiation from the Sun, stars and, in part, the outer layers of planetary atmospheres. This method made it possible to discover the element helium in the Sun even before it was discovered on Earth. The only direct method for studying cosmic bodies was the analysis of the chemical and phase composition of various meteorites that fell to the Earth. Thus, significant material was accumulated, which is of fundamental importance for the further development of spacecraft. Development of astronautics, flights of automatic stations to the planets solar system- The moon, Venus, Mars - and, finally, a visit to the moon by a man opened up completely new opportunities for K. First of all, this is a direct study of the rocks of the Moon with the participation of astronauts or by taking soil samples with automatic (mobile and stationary) devices and delivering them to Earth for further study in chemical laboratories. In addition, automatic descent vehicles made it possible to study matter and the conditions of its existence in the atmosphere and on the surface of other planets in the solar system, primarily Mars and Venus. One of the most important tasks of cosmology is the study of the evolution of cosmic bodies on the basis of the composition and abundance of chemical elements, and the desire to explain their origin and history on a chemical basis. The greatest attention in K. is given to the problems of the abundance and distribution of chemical elements. The abundance of chemical elements in space is determined by nucleogenesis inside stars. Chemical composition The sun, the terrestrial planets of the solar system and meteorites, apparently, are almost identical. The formation of nuclei of chemical elements is associated with various nuclear processes in stars. Therefore, at different stages of their evolution, different stars and stellar systems have a different chemical composition. Stars are known with especially strong spectral lines of Ba or Mg or Li, etc. The distribution of chemical elements over phases in cosmic processes is extremely diverse. The aggregative and phase state of matter in space at different stages of its transformations is influenced in many ways: 1) a huge range of temperatures, from stellar to absolute zero; 2) a huge range of pressures, from millions of atmospheres under the conditions of planets and stars to the vacuum of space; 3) deeply penetrating galactic and solar radiation of various composition and intensity; 4) radiation accompanying the transformation of unstable atoms into stable ones; 5) magnetic, gravitational and other physical fields. It has been established that all these factors affect the composition of the substance of the outer crust of the planets, their gaseous shells, meteorite substance, cosmic dust, etc. At the same time, the processes of fractionation of matter in space concern not only the atomic, but also the isotopic composition. Determination of isotopic equilibria that have arisen under the influence of radiation makes it possible to penetrate deeply into the history of the processes of formation of the matter of planets, asteroids, and meteorites and to establish the age of these processes. Due to extreme conditions in outer space, processes occur and states of matter occur that are not characteristic of the Earth: the plasma state of the matter of stars (for example, the Sun); condensation of He, Na, CH 4 , NH 3 and other volatile gases in the atmosphere of large planets at very low temperatures; the formation of stainless iron in the vacuum of space during explosions on the Moon; chondrite structure of stony meteorites; formation of complex organic matter in meteorites and, probably, on the surface of planets (for example, Mars). In interstellar space, atoms and molecules of many elements are found in extremely low concentrations, as well as minerals (quartz, silicates, graphite, etc.) and, finally, various complex organic compounds are synthesized (arising from the primary solar gases H, CO, NH 3, O 2 , N 2 , S and other simple compounds under equilibrium conditions with the participation of radiation). All these organic substances in meteorites, in interstellar space are optically inactive.

With the development of astrophysics (see Astrophysics) and some other sciences, the possibilities of obtaining information related to spacecraft have expanded. For example, searches for molecules in the interstellar medium are carried out using the methods of radio astronomy. By the end of 1972, more than 20 types of molecules were discovered in interstellar space, including several fairly complex organic molecules containing up to 7 atoms. It has been established that their observed concentrations are 10-100 million times less than the concentration of hydrogen. These methods also make it possible, by comparing the radio lines of the isotopic varieties of one molecule (for example, H 2 12 CO and H 2 13 CO), to study the isotopic composition of the interstellar gas and to check the correctness of existing theories of the origin of chemical elements.

Of exceptional importance for the knowledge of the chemistry of the cosmos is the study of the complex multi-stage process of condensation of low-temperature plasma matter, for example, the transition of solar matter into the solid matter of the planets of the solar system, asteroids, meteorites, accompanied by condensation growth, accretion (increase in mass, "growth" of any substance by adding particles from the outside, for example, from a gas and dust cloud) and agglomeration of primary aggregates (phases) with the simultaneous loss of volatile substances in the vacuum of outer space. In space vacuum, at relatively low temperatures (5000-10000 °C), solid phases of different chemical composition (depending on temperature) successively fall out of the cooling plasma, characterized by different binding energies, oxidation potentials, etc. For example, in Chondrites a distinction is made between silicate, metallic, sulfide, chromite, phosphide, carbide, and other phases, which at some point in their history agglomerate into a stony meteorite and, probably, in a similar way into the matter of terrestrial-type planets.

Further, in the planets, the process of differentiation of the solid, cooling substance into shells takes place - a metal core, silicate phases (mantle and crust) and the atmosphere - already as a result of the secondary heating of the substance of the planets by the heat of radiogenic origin released during the decay of radioactive isotopes of potassium, uranium and thorium and, possibly, , other elements. Such a process of melting and degassing of matter during volcanism is typical for the Moon, Earth, Mars, and Venus. It is based on the universal principle of zone melting, which separates low-melting matter (for example, crusts and atmospheres) from the refractory matter of planetary mantles. For example, the primary solar matter has the ratio Si/Mg≈1, the substance of the planetary crust melted from the mantle of the planets is Si/Mg≈6.5. Preservation and character outer shells planets primarily depend on the mass of the planets and their distance from the Sun (for example, the thin atmosphere of Mars and the powerful atmosphere of Venus). Due to the proximity of Venus to the Sun, a “greenhouse” effect arose from CO 2 in its atmosphere: at temperatures above 300 ° C in the atmosphere of Venus, the process CaCO 3 + SiO 2 → CaSiO 3 + CO 2 reaches an equilibrium state at which it contains 97% CO 2 at 90 pressure atm. The example of the Moon suggests that secondary (volcanic) gases are not retained by a celestial body if its mass is small.

Collisions in outer space (either between particles of meteoritic matter, or during the impact of meteorites and other particles on the surface of planets), due to the enormous cosmic velocities of motion, can cause a thermal explosion that leaves traces in the structure of solid cosmic bodies and the formation of meteorite craters. There is an exchange of matter between space bodies. For example, according to the minimum estimate, at least 1․10 4 t cosmic dust whose composition is known. Among the stone meteorites falling to Earth, there are so-called. basaltic achondrites , close in composition to surface rocks of the Moon and terrestrial basalts (Si/Mg ≈ 6.5). In this regard, a hypothesis arose that their source is the Moon (the surface rocks of its crust).

These and other processes in space are accompanied by the irradiation of matter (high-energy galactic and solar radiation) at numerous stages of its transformation, which leads, in particular, to the transformation of some isotopes into others, and in the general case, to a change in the isotopic or atomic composition of matter. The longer and more diverse the processes in which the matter was involved, the further it is in chemical composition from the primary stellar (solar) composition. At the same time, the isotopic composition of cosmic matter (for example, meteorites) makes it possible to determine the composition, intensity, and modulation of galactic radiation in the past.

The results of research in the field of K. are published in the journals Geochimica et Cosmochimica Acta (N. Y., since 1950) and Geochemistry (since 1956).

Lit.: Vinogradov A.P., High-temperature protoplanetary processes, "Geochemistry", 1971, c. eleven; Aller L. Kh., The prevalence of chemical elements, trans. from English, M., 1963; Seaborg G. T., Valens E. G., Elements of the Universe, trans. from English, 2nd ed., M., 1966; Merrill P. W., Space chemistry, Ann Arbor, 1963; Spitzer L., Diffuse matter in space, N. Y., 1968; Snyder L. E., Buhl D., Molecules in the interstellar medium, Sky and Telescope, 1970, v. 40, p. 267, 345.

A. P. Vinogradov.

Great Soviet Encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

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He studies the chemical composition of cosmic bodies, the laws of abundance and distribution of elements in the Universe, the evolution of the isotopic composition of elements, the combination and migration of atoms during the formation of cosmic matter. The study of chemical ... ... Big Encyclopedic Dictionary

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The science that studies the prevalence and distribution of chemical. elements in space: outer space, meteorites, stars, planets in general and their separate parts. Geological dictionary: in 2 volumes. M.: Nedra. Edited by K. N. Paffengolts and ... Geological Encyclopedia

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The science of chem. composition of space bodies, the laws of prevalence and distribution of elements in the universe, the processes of combination and migration of atoms in the formation of space. in va. The formation and development of K. is primarily associated with the works of V. M. Goldshmidt, G ... Chemical Encyclopedia

cosmochemistry- kosmoso chemija statusas T sritis chemija apibrėžtis Mokslas, tiriantis cheminę kosmoso objektų sudėtį. atitikmenys: engl. cosmic chemistry. cosmochemistry ... Chemijos terminų aiskinamasis žodynas

- (from space and chemistry) the science of chemistry. composition of space bodies, the laws of prevalence and distribution of chemical. elements in the universe, on the synthesis of nuclei chemical. elements and changes in the isotopic composition of elements, about the processes of migration and interaction of atoms during ... Big encyclopedic polytechnic dictionary

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The chemical composition of celestial bodies is determined using spectral analysis.

You can read about spectral analysis on our website:.
Scientists accurately learned the chemical composition of celestial bodies: stars, nebulae, comets. And what is important: they include all known chemical elements on Earth. The discovery of spectral analysis made a revolution in science, since in the recent past it seemed that a person would never be able to know the composition of celestial bodies located at great distances from the Earth. And knowing the chemical composition of a star, one can fairly confidently judge the time of its formation.
The physical properties of matter on the largest scales and the emergence of the universe are studied by science cosmology.
The physical nature of cosmic bodies (their density, temperature, mass, chemical composition, age, education, etc.) is studied by science astrophysics(from the Greek words άστρον - luminary and φύσις - nature).
Astrophysics is based on the laws of physics and on the materials of astronomical observations. The main methods of astrophysics: spectral analysis, photography and photometry (scientific discipline, on the basis of which quantitative measurements of the energy characteristics of the radiation field are made) together with ordinary astronomical observations. It became possible to talk about the birth of astrophysics only after spectral analysis appeared in the second half of the 19th century. The spectra of stars make it possible to determine the temperature, density and chemical composition of the atmosphere of any celestial body, to find out the distance to the stars and their luminosity, to measure the speed of the movement of stars along the line of sight and the speed of their rotation around the axis, to estimate the strength of the magnetic field of stars, to identify the presence of shells of hot gas around the stars .

Consider the study of the chemical composition of stars on the example of the Sun.
The chemical composition of the atmospheres can be recognized by the dark lines of the spectrum. The gas absorbs from the composition of the spectrum of a hotter light source the same rays that it itself emits in a hot state. From this, scientists concluded that the hot surfaces of the Sun and stars give spectra in the form of iridescent stripes, but these surfaces are surrounded by rarefied and less hot gases, which cause dark lines to appear in the spectrum. These gases form atmospheres around the Sun and stars, the chemical composition of which can be recognized by the dark lines of the spectrum. The surfaces of the Sun and stars, although they give the same spectrum as liquid and solid incandescent bodies, are composed of incandescent electrified gases, denser than the atmospheres surrounding them.
The first studies of the solar spectrum were undertaken by one of the inventors of spectral analysis, Kirchhoff, in 1859. The result of these studies was a drawing of the solar spectrum, from which it was possible to determine the chemical composition with great accuracy. solar atmosphere. For example, it is known that the chemical composition of the solar photosphere ( radiating layer of the stellar atmosphere, in which a continuous spectrum of radiation is formed) consists of

Hydrogen 73.46%
Helium 24.85%
Oxygen 0.77%
Carbon 0.29%
Iron 0.16%
Neon 0.12%
Nitrogen 0.09%
Silicon 0.07%
Magnesium 0.05%
Sulfur

The presence of many chemical elements known to us on Earth has been established in the solar atmosphere. Among them gases: hydrogen, nitrogen; metals: sodium, magnesium, aluminum, calcium, iron and many others. In 1942, the presence of a small amount of gold on the Sun was discovered.
Such chemical elements as, for example, chlorine, boron, iodine, mercury and some others have not been found on the Sun by their lines in the spectrum. One of the reasons, perhaps, is that these elements are not in the atmosphere of the Sun, but in its depths. Meanwhile, dark lines in the spectrum cause only those elements that are in the atmosphere of the Sun and absorb light coming from the deeper and denser incandescent layers of the Sun.
It can be assumed that chlorine, boron, iodine, mercury and other elements are present on the Sun or in the solar atmosphere, but we cannot yet detect them.
The spectra of stars, whose light, collected with a telescope, can also be directed to a spectroscope, are similar to the spectrum of the Sun. And by their dark lines it is possible to determine the chemical composition of stellar atmospheres in the same way, they determined the chemical composition of the solar atmosphere by the dark lines of the Sun's spectrum.
It turns out that the chemical composition of the atmospheres of stars differs little from the chemical composition of the Sun and our Earth. In any case, no such chemical elements have been found on the Sun or on the stars that would not be known on Earth. Recall that helium gas, which was first discovered on the Sun, was later found on Earth.
By the clarity with which the dark lines of the spectra of the Sun and stars are visible, it is possible to determine the proportion of each chemical in their atmospheres.

Determination of the chemical composition of celestial bodies based on the study of their spectra is a very difficult task that requires knowledge of the physical conditions in the body under study (especially temperature) and the application of methods of theoretical astrophysics.
As a result of research, scientists have found that some bodies (for example, stars of certain types) have certain features of the chemical composition. However, most of the rest of the objects consist of approximately the same known chemical elements. Therefore, we can only talk about the average cosmic abundance of elements, which is usually judged by the relative number of atoms in any volume.

The book sets out actual problem modern natural science - the origin of life. It is written on the basis of the most modern data of geology, paleontology, geochemistry and cosmochemistry, which refute many traditional, but outdated ideas about the origin and development of life on our planet. The deep antiquity of life and the biosphere, commensurate with the age of the planet itself, allows the author to conclude that the origin of the Earth and life is a single interconnected process.

For readers interested in earth sciences.

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I am only surprised that this incredibly complex mechanism is still working at all. When you think about Life, it becomes clear how pitiful and primitive our science is. It is obvious that the properties of a living being are predetermined by a fertilized cell, just as life is predetermined by the existence of an atom, and the mystery of all that exists lies in the lowest level,

A. Einstein

The relationship between the germs of life and its predecessors - complex carbon compounds - is a paramount scientific problem. The first experiments of L. Pasteur, staged in the second half of the 19th century, showed the impossibility of the origin of life - the simplest living organisms - under modern conditions on the Earth. This to some extent led to the emergence of the ideas of panspermia, according to which life on Earth never originated at all, but was brought from outer space, where it existed in the form of embryos. The most characteristic supporters of these ideas were G. Helmholtz and S. Arrhenius, although earlier such ideas were expressed by J. Liebig. According to S. Arrhenius, particles of living matter - spores or bacteria, settled on microparticles of cosmic dust, are transferred from one planet to another by the force of light pressure, while maintaining their viability. When spores hit a planet with suitable conditions for life, they germinate and give rise to biological evolution.

In somewhat different forms, these ideas are being revived in our time. For example, F. Hoyle put forward the idea of the possibility of the existence of microorganisms in interstellar space. According to his ideas, clouds of cosmic dust are composed mainly of bacteria and spores. It is assumed that in the time interval 4.6-3.8 billion years ago, two events were possible on Earth - either the origin of life on the planet itself, or it brought microorganisms from outer space. F. Hoyle and S. Wickramasing in 1981 admitted that the latter is more likely. According to their calculations, 10 18 cosmic spores enter the Earth's upper atmosphere every year as a remnant of solid material dispersed in the solar system. Thus, comets are carriers of the germs of life, which were formed earlier in interstellar space and only then fell into the Oort cloud.

It should be noted that the presented ideas are extremely fantastical and do not agree with the known experimental data. However, there is no doubt that life is connected with the cosmos in terms of atomic composition and in terms of energy. This can be seen from Table. 6, which gives the values of the relative distribution of elements in space, in the volatile fraction of comets, in bacteria and mammals. Attention is drawn to the great proximity, and in some cases, the identity of cosmic matter and the living matter of the Earth. The main elements of living matter are the widespread elements of the cosmos. At the same time, H, C, N, O - typical biophilic elements - are the most widely distributed in nature.

It is easy to conclude that living organisms primarily use the most accessible atoms, which, in addition, are capable of forming stable and multiple chemical bonds. It is known that carbon can form long chains, resulting in countless polymers. Sulfur and phosphorus can also form multiple bonds. Sulfur is part of proteins, and phosphorus is part of nucleic acids.

Under the right conditions, the most common atoms combine with each other to form molecules, which are found in cosmic clouds by the methods of modern radio astronomy. Most of the known cosmic molecules are organic, including the most complex 8- and 11-atomic ones. Thus, with regard to composition, the cosmochemistry of the Universe creates extensive possibilities for various combinations of carbon with other elements according to the laws of chemical bonding.

However, the problem of the formation of molecules in cosmic conditions is one of the most difficult problems of cosmochemistry. Actually, in the interstellar medium, even in its densest regions, the elements are in conditions far from thermodynamic equilibrium. Due to the low concentration of the substance chemical reactions in interstellar space is extremely unlikely. Therefore, it was suggested that particles of cosmic dust take part in the construction of interstellar molecules. In the simplest case, hydrogen molecules can appear when its atoms come into contact with solid particles. The most common space molecules, CO, are probably capable of being born in stellar atmospheres at a sufficient density of matter and then ejected into outer space.

At present, the role of the solid phase in the formation of molecules of organic substances in outer space is becoming more and more clear. The most probable models of this process were developed by J. Greenberg. According to the scientist, cosmic dust particles have complex structure and consist of a core of predominantly silicate composition, surrounded by a shell of organic substances. Apparently, various chemical processes take place in the shell, leading to the complication of the structure of the original substance. The structure of such dust particles after the first stage of accretion is confirmed by experimental modeling on a mixture of water, methane, ammonia and other simple molecules irradiated with ultraviolet radiation at a temperature of about 10 K. Each dust grain originates from a silicate core that arose in the atmosphere of a cold giant star. An ice shell forms around the core. Under the influence ultraviolet radiation some shell molecules (H 2 O CH 4, NH 3) dissociate with the formation of radicals - reactive fragments of molecules. These radicals can recombine to form other molecules. As a result of prolonged irradiation, a more complex mixture of molecules and radicals (HN 2 HCO, HOCO, CH 3 OH, CH 3 C, etc.) may appear. When dust grains are destroyed under the influence of cosmic factors, the compounds that have arisen on their surface form molecular clouds.

Judging by the huge masses of molecular clouds, they are the main reservoirs of organic matter in space. However, found in them organic compounds turn out to be relatively simple and still far from those molecular systems that could provide the beginning of life on any favorable planetary body.

The presence of organic substances in meteorites deserves special attention. This is very important for understanding the processes of the origin of high-molecular systems as the precursors of life. It should be noted that meteorites, together with their parent bodies - asteroids, belong to the solar system. Further, the age of meteorites, according to nuclear geochronology, is 4.6-4.5 billion years, which basically coincides with the age of the Earth and the Moon. Consequently, meteorites undoubtedly witness the formation of various chemical compounds, including organic ones, at the earliest stages of the development of the solar system.

Meteorites contain hydrocarbons, carbohydrates, purines, pyrimidines, amino acids, i.e. those chemical compounds that are part of living matter, forming its basis. They are found in carbonaceous chondrites and asteroids of certain structure and composition. Most asteroids move in the belt between Mars and Jupiter. Based on data on the cosmochemistry of comets, it can be assumed that the region of formation of organic compounds covered a vast area within most of the volume of the primary solar nebula. Naturally, in elucidating the general problem of the origin of life, we have no right to ignore data on the composition of meteorites. This circumstance was taken into account to varying degrees by different authors of hypotheses about the origin of life. Thus, we are now entitled to consider the known meteorites as historical documents- authentic witnesses early history The solar system, which also covers the processes of formation of organic matter.

Any meteorite is solid, consisting of a number of mineral phases. The main ones are silicate (stone), metallic (iron-nickel) and sulfide (troilite). There are also other phases, but they are of secondary importance in their distribution. Various minerals are found in meteorites, the number of which exceeds 100, but only a few are the main rock-forming minerals (olivine, pyroxene, feldspars, nickel iron, troilite, etc.). In addition, 20 minerals were found in meteorites, which are not found in the earth's crust. These include carbides, sulfides, etc., the formation of which is associated with sharply reducing conditions. The most significant concentrations of carbon associated with organic matter are in carbonaceous chondrites.

Fundamentally important information about organic matter in meteorites is presented in the works of G. P. Vdovykin, E. Avders, R. Hayatsu, M. Studir. The famous chemist I. Berzelius was the first to single out organic matter in the composition of meteorites when analyzing the carbonaceous chondrite Alais in 1834. The results of his analysis were so impressive that he himself considered this substance of biological origin. During the 19th century, chemical analyzes revealed the presence of solid hydrocarbons, complex organic compounds with sulfur and phosphorus in meteorites. Carbonaceous chondrites, a significant part of the carbon in which is in the form of organic compounds, have been studied most carefully and thoroughly. The total content of carbon and some other volatile substances in carbonaceous chondrites is characterized by the following values (in wt.%):

This shows that the content of carbon (as well as sulfur and water) is maximum in carbonaceous chondrites of the C1 type, and minimum in C3 chondrites. Thus, at present, there is no doubt that in the parent bodies of carbonaceous chondrites, as a result of the very processes of their formation, complex organic compounds arose as a natural result of the chemical evolution of the early solar system.

The elemental chemical composition of carbonaceous chondrites minus volatile substances is very close to that of ordinary chondrites. The main features of the various types of carbonaceous chondrites are as follows.

Type C1 is represented by fragile black stones, crumbling to dust when rubbed with fingers. The fine-grained mass in them is approximately 95%. It is interspersed with chondrules (microchondrules) consisting of olivine and magnetite (1-50 microns in size). The mineral composition of this type of meteorite is shown in fig. 9. Carbonaceous chondrites of type C1 are the richest in organic substances of abiogenic origin.

Type C2 are greyish-black stones, significantly denser than C1. The main fine-grained mass, which makes up 60% of the volume, is interspersed with significantly larger chondrules than in type C1. Intergrowths of primary microchondrules into a single crystal are observed.

Type C3 are hard stones that are dark gray, greenish gray or gray in color. Fine-grained mass occupies 35%. The chondrules are quite large and well defined.

The abundance of many chemical elements in carbonaceous chondrites of the C1 type reveals a number of characteristic relationships that bring them closer to the solar matter. In other words, these carbonaceous chondrites are solidified solar matter, devoid of light gases.

Organic substances found in meteorites are listed in Table. 7. As you can see, their list is quite impressive. Most of these compounds, to one degree or another, correspond to the universal links of metabolism known in living organisms: amino acids, protein-like polymers, mono- and polynucleotides, porphyrins, and other compounds. The proximity to the composition of organic complexes of biological origin turned out to be so great that some authors even began to admit that in the past living organisms were found directly in the meteorites themselves. There was a lively discussion on this issue in the 1960s. However, careful studies of organic compounds from meteorites did not confirm the presence of optical activity, which indicates their abiogenic origin.

A comparison of organic substances of meteorite origin with products of artificial reactions of the Fischer-Tropsch type and fossil organic substances of biological origin shows their great proximity, in particular with regard to the content of certain hydrocarbons. For example, meteorites are dominated by hydrocarbons with 16 atoms per molecule, which is also observed in terrestrial objects and products of laboratory experiments.

Meteorites are fragments of larger bodies - asteroids, most of which are located in the asteroid belt at a distance of 2.3-3.3 AU. e. from the Sun. Over the past 10 years, as a result of astrophysical observations of asteroids in the visible part of the spectrum and infrared waves, data have been obtained that are of paramount importance for establishing the genetic relationship between asteroids and meteorites. By comparing the reflectivity of meteorites and asteroids, it was possible to establish that almost all known classes of meteorites have their analogues among the studied asteroids.

Depending on the reflectivity, asteroids are divided into two main large groups - dark, or C-asteroids, and relatively light, or S-asteroids. The former are characterized by low albedo - less than 0.05, the latter - over 0.1. In terms of spectral reflectivity, the group With close to carbonaceous chondrites, a S- to stony-iron meteorites and ordinary chondrites. The latest photometric measurements generally confirm the unity of the material of meteorites and asteroids. Therefore, all the mineral, chemical, and structural features of meteorites obtained and studied in terrestrial laboratories can be transferred to asteroids.

As a result of the research, it was possible to establish that the composition of asteroids is different in different regions of the asteroid belt. A fundamentally important cosmochemical regularity has been revealed within the solar system: the composition of asteroids depends on the heliocentric distance. In the inner part of the asteroid belt there are bodies close to ordinary chondrites, but as the distance from the Sun increases, within 2.5-3.3 AU. That is, they become smaller, and the number of asteroids such as carbonaceous chondrites, which occupy a dominant position in the middle and marginal parts of the asteroid belt, increases. In general, according to modern observations, even carbonaceous-chondrite bodies predominate in the asteroid belt.

If indeed most asteroids have the composition of carbonaceous chondrites, then it is quite natural that they contain a lot of organic matter, which determines their dark color and low reflectivity. Thus, the asteroid Bamberg has the lowest reflectivity (albedo 0.03). This is a dark and rather large object in the asteroid belt, with a diameter of about 250 km.

Comets have been of great interest lately. It has been suggested that they participated in the emergence of life on Earth, or in any case could make a certain contribution to the composition of its early atmosphere. They could also deliver the first organic molecules. The opinion was established that comets best of all reflect the primary conditions in the solar system.

Most comets are located on the very periphery of the solar system, in the so-called Oort cloud. They have extremely elongated orbits and are hundreds and thousands of times farther from the Sun than Pluto. Long-period comets approach the Sun from a distant region. In general, the comet is a lump of dirty snow. The "snow" in the comet is composed of ordinary water ice mixed with carbon dioxide and other frozen gases of unknown composition. "Mud" is particles of silicate rocks of various sizes interspersed in cometary ice. It can be assumed that, due to the absence of chemical interactions, comets are untouched samples of the original matter from which the solar system was formed.

As they approach the Sun, the volatile matter of comets evaporates and is thrown off by light pressure, forming a giant tail. All observed cometary phenomena are determined by processes associated with the release of gases and dust. The H + , OH - , O - and H 2 O + ions that make up cometary tails come mainly from water molecules, although other hydrogen compounds are also likely to be present. Atoms, radicals, molecules and ions are presented in the following form: in comets - C, C 2, C 3, CH, CN, CS, CH 3 CN, HCN, NH, NH 2, O, OH, H 2, O 2, Na, S, Si; near the Sun - Ca, CO, Cr, Cu, Fe, V; in the tail - CH + , CO + , CO 2 + , CN + , N 2 + .

Everywhere in comets, biophilic elements are found, mainly C, O, N and H. At present, with a high degree of probability, it has been established that cometary molecules are close to those necessary for pre-biological evolution. They can be represented by molecules of amino acids, purines, pyrimidines. As noted by A. Delsemm, there are several groups of data indicating that cometary dust is of the nature of chondrite meteorites. First, it consists predominantly of silicates and carbon compounds. Secondly, the ratios of metals evaporated from comets during their passage near the Sun correspond to ratios typical for chondrites. Thirdly, dust particles of cosmic origin, probably reflecting the matter of comets, are very close to the composition of the material of carbonaceous chondrites. Indeed, analysis of cosmic dust samples indicates that 80% or more of dust particles smaller than 1 mm are composed of a material similar to carbonaceous chondrites. Some scientists have compared the carbon content in comets and carbonaceous chondrites and have concluded that at least 10% of comet material is organic compounds. The nature of the chemical compounds found in comets indicates a high probability that the molecules that give rise to them are at least comparable in complexity to the molecules of interstellar space.

Thus, all data on the cosmochemistry of meteorites, asteroids, and comets indicate that the formation of organic compounds in the solar system at the early stages of its development was a typical and massive phenomenon. It manifested itself most intensely in the space of the future asteroid ring, but to varying degrees it covered other regions of the protoplanetary solar nebula, including, probably, the region from which the Earth arose. However, the chemical evolution of the matter of the protosolar nebula, having reached certain stage The formation of complex organic compounds turned out to be frozen in most bodies of the solar system, and only on Earth did it continue, reaching incredible complexity in the form of living matter.

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In 1806, at the height of the Napoleonic Wars, an unusual meteorite fell near the French town of Ale. It was only three years after the meteorites were officially "Recognized" by the Paris Academy of Sciences. Prejudices against the "Heavenly Stones" were still very strong, some of the fragments of the Ale meteorite were simply lost, and only one of them after 28 years ended up in the laboratory of the famous Swedish chemist Jens Jakob Berzelius

At first, the scientist thought that there was a mistake - the Ale meteorite was neither stone, nor iron, nor iron-stone. Melting bark ( surface layer), however, testified to the cosmic origin of an unusual stone, the ancestor of the rarest and then still unknown type of meteorites - carbonaceous chondrites.

The Ale meteorite contained an organic mass soluble in water. When heated, its particles turned brown and charred - a clear sign of the presence of organic compounds, carbon compounds. (We recall that such simple carbon-containing compounds as co, co 2, carbonic acid H 2 co 3 and its salts are inorganic compounds.) Although the similarity with terrestrial substances of the same type was obvious, Berzelius reasonably noted that this fact "is not yet Proof of the Presence of Organisms in the Original Source."

Berzelius' work marked the beginning of the study of organic compounds in meteorites. Unfortunately, the material available for research is still very rare. Carbonaceous chondrites are very fragile - they are easy to grind into powder even with your fingers (and at the same time, we repeat, a characteristic smell of oil appears. In general, rare among meteorites, carbonaceous chondrites are also easily destroyed when flying in the earth's atmosphere. Yes, and hitting earth's surface, they, as a rule, disappear without a trace, mixed with terrestrial rocks. It is not surprising, therefore, that so far only two dozen carbonaceous chondrites have been found and preserved throughout the world.

Four years after the works of Berzelius were published, in 1838 another carbonaceous chondrite fell in South Africa, which was then investigated by the famous German chemist Friedrich Wöhler - the same Wöhler, who a few years earlier managed to obtain a substance of animal origin - urea - from inorganic matter.

Wöhler isolated an oily oily substance “with a Strong Bituminous Smell” from a meteorite and, unlike Berzelius, came to the conclusion that such substances, “based on the current level of knowledge”, can only be synthesized by living organisms. Note that the amount of organic material released from carbonaceous hopdrites is small - about one percent. But even this is quite enough to draw very important conclusions.

In 1864, again in France, near the village of orgueil, a meteorite shower of carbonaceous chondrites fell - an exceptional case in the history of astronomy. The French chemist Klets proved rigorously that the water-insoluble black substance of the Orgueil meteorite is organic compounds, and not at all graphite or amorphous carbon. He was struck by the similarity of these organic compounds with similar substances found in peat or brown coal. In a paper presented to the Paris Academy of Sciences, Klets argued that the organic matter in meteorites "seems to indicate the existence of Organized Matter on Celestial Bodies."

Since then, for almost a century, the study of the organics of meteorites has been carried out episodically, from case to case, without any significant generalizations. Among these few works, mention should be made of the study of the Migei meteorite, carried out in 1889 by Yu. and. simashko. The Russian scientist also discovered bituminous-type organic substances in this carbonaceous chondrite.

Photo carbonaceous chondrite.
One should not think that all organic substances are necessarily associated with life or, moreover, are the property of living beings. Astronomers are aware of numerous simple carbon-containing formations, which certainly have no direct relation to life. Such are, say, the CH and CN radicals observed in interstellar space and the atmospheres of cold stars. Moreover, in outer space, apparently, the synthesis of very complex organic compounds up to and including amino acids is constantly going on. We are convinced of this, in particular, by the curious experiments of the American researcher R. Berger. With the help of an elementary particle accelerator, he bombarded with protons a mixture of methane, ammonia and water, cooled to - 230 s. just a few minutes later, in this ice mixture, the scientist discovered urea, acetamide, acetone. In these experiments, Berger, in fact, simulated the conditions of interplanetary space. The proton stream imitated primary cosmic rays, and the mixture of methane-ammonia and ordinary ices is, in essence, a typical model of a cometary nucleus.

Another well-known American biochemist, M. Calvin, bombarded a mixture of hydrogen, methane, ammonia, and water vapor with a stream of fast electrons. In these experiments, adenine was obtained - one of the four nitrogenous bases that make up nucleic acids. Didn't such processes take place in the primary atmosphere of the earth and some other planets?

It seems that in space, from inorganic substances and in an inorganic way, protein-like compounds are created - "Semi-finished products" of a possible future life.

Thus, the presence of organic matter in meteorites in itself cannot in any way indicate the existence of life on celestial bodies. These substances could also arise abiogenically, without any direct connection with life. Stronger arguments are needed to prove the contrary.

It is in this regard that the discussion in the modern science of meteorites is being conducted. The dispute is not over yet, but the results obtained are of great interest.

Back in 1951-1952. English biochemist Müller isolated bituminous compounds from carbonaceous chondrint. In essence, he repeated the works of Berzelius, Wöhler, and Kletsz, but on an incomparably higher level. Meteoritic bitumen contains much more sulfur, chlorine and nitrogen than similar terrestrial compounds, this circumstance prompted Muller to conclude that the bitumen in meteorites is of abiogenic origin.

The already mentioned M. Calvin and s. out. Their report, presented in 1960 to an international symposium on the study of outer space, was titled meaningfully: "extraterrestrial life. Some organic constituents of meteorites and their significance for possible biological evolution outside the earth." American researchers isolated volatile substances from carbonaceous chondrite samples, which were then passed through a mass spectrometer. In these experiments, the relative mass of fragments of unknown molecules was determined and, in addition, the infrared and ultraviolet spectra of extracts of carbon-containing meteorite compounds were studied. The results have been stunning.

From carbonaceous chondrite, it was possible to isolate a substance like two drops of water similar to cytosine - another of the four nitrogenous bases. Found in a meteorite and a mixture of hydrocarbons, similar to oil of terrestrial origin.

The following year, 1961, the work of three American chemists, G. Nagy, D. Hennessey, and W. maintain. From carbonaceous chondrites, they isolated a set of paraffins, very similar to that which is part of the peel of apples or beeswax. In this regard, the disputes around the problem of the origin of oil have intensified.

We still do not know exactly where oil came from - a source of fuel for aircraft, ships and cars, the most valuable raw material for petrochemistry. Was oil formed as a result of the decomposition of once living organisms, or is "Black Gold" a product of some complex abiogenic synthesis? If the first hypothesis is correct, bitumens in meteorites can be considered as traces of extraterrestrial life. Only if the oil is of inorganic origin, then meteorite bitumen has no direct relation to life outside the earth, but, apparently, arose as a result of abiogenic processes.

We have already spoken about experiments simulating the formation of organic compounds in interplanetary space. It is even easier to imagine such an abiogenic synthesis in the bowels of an Earth-like planet. Organic substances in meteorites arose abiogenically - this is the main thesis of those who do not consider meteorites to be carriers of the remains of some extraterrestrial organisms. This position is defended by Anders, Briggs, in our Soviet Union - the researcher of carbonaceous chondrites G. P. Vdovykin. In his opinion, "the study of the spectra of various celestial bodies shows that carbon is one of the most common elements in them: it is found in the form of an element (c 2, c 3) and in the form of compounds (CH 2, CN, co 2, etc. .) In all types of celestial bodies, these components of the atmosphere and starry space could polymerize with the formation of complex organic molecules "(L. Kuznetsova. Thirteen riddles of the sky. M., Soviet Russia, 1967 light.

The most lively discussions are now around the mysterious "Organized Elements". For the first time, these strange inclusions with a diameter of 5 to 50 microns were discovered in 1961 by N. Nagy and D. Klaus while studying samples of four carbonaceous chondrites. Outwardly, they resembled terrestrial fossil microscopic algae. Among them, American researchers identified five types of objects according to morphological features, and some of the objects turned out to be paired, as if they died in the process of cell division. Almost all of the "Organized Elements" looked like the simplest plants that live only in water, and this circumstance, according to Nagy and Klaus, excluded the possibility of contamination of the meteorite from the soil. Later, F. Staplen and others discovered "Organized Elements" in a number of carbonaceous chondrites, and all researchers noted their similarity with some unicellular algae.

In 1962, the Leningrad geologist b. in. Timofeev isolated strange spore-like formations from the Saratov and Migeya meteorites. There were more than two dozen of them - yellowish-gray, tiny, hollow, almost spherical shells, having a diameter of 10 to 60 microns. The shells turned out to be single-layered, different in thickness, sometimes crumpled into distinctly defined folds. According to the researcher, "the surface of the shells is smooth, less often finely tuberculate. One of the forms shows a round hole - a stomata, characteristic of some unicellular algae. Many of these Finds can be compared with the oldest fossil unicellular algae on earth that lived more than 600 million years ago ago, but they cannot be attributed to any group flora our planet" (light, 1962, number 4, p. 12.

Nucleic acids

Deoxyribonucleic and ribonucleic acids are universal components of all living organisms responsible for the storage, transmission and reproduction (realization) of genetic information. All N. to. are divided into two types according to the carbohydrate component of the molecules: deoxyribose in deoxyribonucleic acids (DNA) and ribose in ribonucleic acids (RNA). Biological role DNA in most organisms is the storage and reproduction of genetic information, and RNA - in the implementation of this information in the structure of protein molecules (Proteins) in the process of their synthesis.

Nucleic acids were discovered in 1868 by the Swiss scientist F. Miescher, who found that these substances are localized in the nuclei of cells, have acidic properties and, unlike proteins, contain phosphorus. Chemically, N. to. are polynucleotides, i.e. biopolymers built from monomer units - mononucleotides, or nucleotides (phosphorus esters of the so-called nucleosides - derivatives of purine and pyrimidine nitrogenous bases, D-ribose or 2-deoxy-D-ribose). The purine bases included in the DNA molecule are adenine (A) and guanine (G), pyrimidine bases are cytosine (C) and thymine (T). In RNA nucleosides, uracil (U) is present instead of thymine. In a polynucleotide chain, nucleotides are connected via a phosphodiester bond (Fig. 1).

The primary structure of N. to. is determined by the order of alternation of nitrogenous bases, and their spatial configuration is determined by non-covalent interactions between sections of the molecule: hydrogen bonds between nitrogenous bases, hydrophobic interactions between base pair planes, electrostatic interactions involving negatively charged phosphate groups and counterions.

Deoxyribonucleic acids isolated from various organisms differ in the ratio of nitrogenous bases included in their composition, i.e. according to the nucleotide composition, which in all DNA obeys the Chargaff rule: 1) the number of adenine molecules in the N. molecule is equal to the number of thymine molecules, i.e. A = T; 2) the number of guanine molecules is equal to the number of cytosine molecules, i.e. G = C; 3) the number of molecules of purine bases is equal to the number of molecules of pyrimidine bases; 4) the number of 6-amino groups is equal to the number of 6-keto groups, which means that the sum of adenine + cytosine is equal to the sum of guanine + thymine, i.e. A + C \u003d G + T. Chargaff's rule is also true for the so-called minor nitrogenous bases (methylated or other derivatives of purine and pyrimidine bases). Thus, the nucleotide composition of each DNA is characterized constant value- molar ratio

(specificity factor) or the percentage of G-C pairs, i.e.

The value of the latter indicator is practically the same for organisms of the same class. In higher plants and vertebrates, it is 0.55-0.93.

A study published in the journal Nature showed that organic compounds, with an unexpected high level complexities exist throughout the universe. These results suggest that complex organic compounds can be created by stars.

Professor Sun Quoc and Dr. Yong Zhang of the University of Hong Kong have demonstrated that organic substances in the universe are composed of both aromatic (cyclic form) and aliphatic (chain) compounds. These compounds are so complex that their chemical structure resembles coal or oil. Since coal and oil are the remnants of ancient life, it was believed that this form of organic matter was formed exclusively from living organisms. The team's discovery suggests that complex organic compounds can be synthesized in space even in the absence of any life forms.

Scientists have investigated a mysterious phenomenon: a set of infrared radiation in stars, interstellar space and galaxies. Their spectral signatures are known as "unidentified infrared emissions". For more than two decades, the most widely accepted theory regarding the origin of these signatures has been that they are simple organic molecules made up of carbon and hydrogen atoms called polycyclic aromatic hydrocarbons (PAHs). By observing with the Infrared Space Observatory and the Spitzer Space Telescope, Kuok and Zhang demonstrated that the emission spectrum could not be explained by the presence of PAH molecules. The team put forward the opinion that substances that generate such infrared radiation have a much more complex chemical structure.

Stars not only create this complex organic matter, but also push it out into interstellar space. The results are consistent with Kuok's earlier idea that old stars are molecular factories capable of producing organic mixtures. "Our work has demonstrated that stars can easily create complex organic compounds in a near-total vacuum," Kuok said. "Theoretically it's impossible, but we can still see it."

Even more interesting is the fact that the structure of this organic star dust is similar to the complex organic compounds found in meteorites. Since meteorites are remnants of the early solar system, the question arises as to whether the stars could have enriched the early solar system with organic compounds. The question of what role these compounds played in the process of the origin and development of life on Earth remains open.

“Carbon occurs in nature both in the free and in the combined state, in a very various forms and types. In the free state, carbon is known in at least three forms: coal, graphite, and diamond. In the state of compounds, carbon is part of the so-called organic substances, that is, many substances found in the body of every plant and animal. It is found in the form of carbon dioxide in water and air, and in the form of salts of carbon dioxide and organic residues in soil and mass earth's crust. The variety of substances that make up the body of animals and plants is known to everyone. Wax and oil, turpentine and resin, cotton paper and protein, plant cell tissue and animal muscle tissue, tartaric acid and starch - all these and many other substances included in the tissues and juices of plants and animals are carbon compounds. The field of carbon compounds is so large that it constitutes a special branch of chemistry, i.e., the chemistry of carbon or, better, hydrocarbon compounds.

These words from the Fundamentals of Chemistry by D. I. Mendeleev serve as a detailed epigraph to our story about the vital element - carbon. However, there is one thesis here, which, from the point of view of modern science of matter, can be argued, but more on that below.

Probably, the fingers on the hands will be enough to count the chemical elements that at least one scientific book has not been devoted to. But an independent popular science book - not some kind of brochure on 20 incomplete pages with a wrapping paper cover, but a quite solid volume of almost 500 pages - has only one element in the asset - carbon.

In general, the literature on carbon is the richest. These are, firstly, all the books and articles of organic chemists without exception; secondly, almost everything related to polymers; thirdly, countless publications related to fossil fuels; fourthly, a significant part of the biomedical literature ...

Therefore, we will not try to embrace the immensity (it is not by chance that the authors of the popular book on element No. 6 called it “Inexhaustible”!), but we will focus only on the main thing from the main point - we will try to see carbon from three points of view.

Carbon is one of the few "no family, no tribe" elements. The history of human contact with this substance goes back to prehistoric times. The name of the discoverer of carbon is unknown, and it is also unknown which of the forms of elemental carbon - diamond or graphite - was discovered earlier. Both happened way too long ago. Only one thing can be definitely stated: before diamond and before graphite, a substance was discovered, which a few decades ago was considered the third, amorphous form of elemental carbon - coal. But in reality, charcoal, even charcoal, is not pure carbon. It contains hydrogen, oxygen, and traces of other elements. True, they can be removed, but even then the coal carbon will not become an independent modification of elemental carbon. This was established only in the second quarter of our century. Structural analysis showed that amorphous carbon is essentially the same graphite. This means that it is not amorphous, but crystalline; only its crystals are very small and there are more defects in them. After that, they began to believe that carbon on Earth exists only in two elementary forms - in the form of graphite and diamond.

Video Organic compounds in space

Alkanes. Structure and nomenclature

By definition, alkanes are saturated or saturated hydrocarbons that have a linear or branched structure. Also called paraffins. Alkanes contain only single covalent bonds between carbon atoms. The general formula is

To name a substance, you must follow the rules. According to the international nomenclature, names are formed using the suffix -an. Titles first four alkanes have developed historically. Starting from the fifth representative, the names are made up of a prefix indicating the number of carbon atoms, and the suffix -an. For example, octa (eight) makes octane.

For branched chains, the names add up:

from the numbers indicating the numbers of carbon atoms around which the radicals stand;
from the name of the radicals;
from the name of the main chain.

Example: 4-methylpropane - the fourth carbon atom in the propane chain has a radical (methyl).

Rice. one. Structural formulas with the names of alkanes.

Every tenth alkane names the next nine alkanes. After decane come undecane, dodecane, and so on; after eicosan, geneicosan, docosan, tricosan, etc.

organic and inorganic substances. organic matter

Organic compounds differ from inorganic compounds primarily in their composition. If inorganic substances can be formed by any elements of the Periodic system, then C and H atoms must certainly be included in the composition of organic substances. Such compounds are called hydrocarbons (CH4 - methane, C6H6 - benzene). Hydrocarbon raw materials (oil and gas) are of great benefit to mankind. However, the strife causes serious.

Derivatives of hydrocarbons also contain O and N atoms in their composition. Representatives of oxygen-containing organic compounds are alcohols and isomeric ethers(C2H5OH and CH3-O-CH3), aldehydes and their isomers - ketones (CH3CH2CHO and CH3COCH3), carboxylic acids and esters (CH3-COOH and HCOOCH3). The latter also include fats and waxes. Carbohydrates are also oxygen-containing compounds.

Why did scientists combine plant and animal substances into one group - organic compounds, and how do they differ from inorganic ones? There is no single clear criterion for separating organic and inorganic substances. Consider a number of features that combine organic compounds.

Composition (constructed from atoms C, H, O, N, less often P and S).
Structure (C-H and C-C bonds are mandatory, they form different lengths chains and cycles);
Properties (all organic compounds are combustible, form CO2 and H2O during combustion).

Among organic substances, there are many polymers of natural (proteins, polysaccharides, natural rubber, etc.), artificial (viscose) and synthetic (plastics, synthetic rubbers, polyester, and others) origin. They have great molecular weight and more complex, in comparison with inorganic substances, structure.

Finally, there are more than 25 million organic substances.

This is just a superficial look at organic and inorganic substances. More than a dozen have been written about each of these groups. scientific papers, articles and textbooks.

As we have already indicated above, the whole set of organisms belonging to all the kingdoms of nature is considered to be the living substance of the considered shell of the Earth. Human beings occupy a special position among all. The reasons for this were:

consumer position, not production;
development of mind and consciousness.

All other representatives are living matter. The functions of living matter were developed and indicated by Vernadsky. He assigned the following role to organisms:

Redox.
Destructive.
Transport.
Environment-forming.
Gas.
Energy.
Informational.
concentration.

The most basic functions of the living matter of the biosphere are gas, energy and redox. However, the rest are also important, providing complex processes of interaction between all parts and elements of the living shell of the planet.

Let's consider each of the functions in more detail to understand what exactly is meant and what is the essence.

Cosmochemistry Cosmochemistry is the science of the chemical composition of cosmic bodies, the laws of the abundance and distribution of chemical elements in the Universe, the processes of combination and migration of atoms during the formation of cosmic matter. Geochemistry is the most studied part of cosmochemistry. Cosmochemistry is the science of the chemical composition of cosmic bodies, the laws of the prevalence and distribution of chemical elements in the Universe, the processes of combination and migration of atoms during the formation of cosmic matter. Geochemistry is the most studied part of cosmochemistry.

Chemistry of the earth

The chemical composition of the meteorite Chemical analyzes of meteorites that fell on our planet gave remarkable results. If we calculate the average content in all meteorites of the most common elements on Earth: iron, oxygen, silicon, magnesium, aluminum, calcium, then exactly 94% falls on their share, i.e., they are equal in the composition of meteorites as in the composition the globe.

Chemistry of interstellar space Not so long ago, science assumed that interstellar space is a void. All matter in the Universe is concentrated in the stars, and there is nothing between them. Only within the solar system, somewhere along unknown paths, meteorites and their mysterious counterparts, comets, wander. Not so long ago, science assumed that interstellar space is a void. All matter in the Universe is concentrated in the stars, and there is nothing between them. Only within the solar system, somewhere along unknown paths, meteorites and their mysterious counterparts, comets, wander. The chemistry of interstellar space is surprisingly complex. In space, the simplest radicals were discovered: for example, methine (CH), hydroxyl (OH). Where there is hydroxyl, there must be water, and it has indeed been found in interstellar space. In space there is water, organic molecules (formaldehyde), ammonia. These compounds, reacting with each other, can lead to the formation of amino acids.

Lunar chemistry Moon rocks are special - their composition is affected by the lack of oxygen. There was no free water or atmosphere on the Moon. All volatile compounds that arose during magmatic processes flew into space. Stony meteorites are composed of simple silicates, the number of minerals in them barely reaches a hundred. There are slightly more minerals in lunar rocks than in meteorites - probably several hundred. And more than 3 thousand minerals have been discovered on the surface of the Earth. This indicates the complexity of terrestrial chemical processes in comparison with the lunar ones.

The chemical composition of the planets Mercury - the closest planet to the Sun, Mercury is covered with silicate rocks similar to those of the Earth. The composition of the atmosphere of Venus is about 97% carbon dioxide (CO2), nitrogen (N2) no more than 2%, water vapor (H2O) about 1%, oxygen (O2) no more than 0.1%.

The chemical composition of the planets The atmosphere of this planet consists of carbon dioxide, there is some nitrogen, oxygen and water vapor. Soviet and American scientists sent automatic research stations to Mars as well. Mars is a cold, lifeless, dusty desert. The most interesting, amazing and mysterious planet in terms of chemistry is Jupiter. Jupiter is 98% hydrogen and helium. Water, hydrogen sulfide, methane and ammonia were also found.

The chemical composition of the planets The atmosphere of Uranus consists of approximately 83% hydrogen, 15% helium and 2% methane. Like other gas planets, Uranus has cloud bands that move very quickly. The structure and set of elements that make up Neptune are probably similar to Uranus: various "ices" or solidified gases containing about 15% hydrogen and a small amount of helium Saturn's atmosphere is mainly hydrogen and helium.

METALS IN SPACE Titanium today is the most important structural material. This is due to the rare combination of lightness, strength and refractoriness of this metal. On the basis of titanium, many high-strength alloys have been created for aviation, shipbuilding and rocket technology. Titanium today is the most important structural material. This is due to the rare combination of lightness, strength and refractoriness of this metal. On the basis of titanium, many high-strength alloys have been created for aviation, shipbuilding and rocket technology.

Fullerenes in space fullerenes branched chain hydrocarbons fullerenes branched chain hydrocarbons Fullerenes were first found outside the Milky Way