Supernova SN2010jl Photo: NASA/STScI

For the first time, astronomers have observed the formation of cosmic dust in the immediate vicinity of a supernova in real time, allowing them to explain this mysterious phenomenon that occurs in two stages. The process begins shortly after the explosion but continues for many more years, the researchers write in the journal Nature.

We are all made up of stardust, of the elements that are the building material for new celestial bodies. Astronomers have long assumed that this dust is formed when stars explode. But how exactly this happens and how dust particles are not destroyed in the vicinity of galaxies, where there is an active one, has so far remained a mystery.

This question was first clarified by observations made with the Very Large Telescope at the Paranal Observatory in northern Chile. An international research team led by Christa Gall (Christa Gall) from the Danish University of Aarhus investigated a supernova that occurred in 2010 in a galaxy 160 million light years away from us. The researchers observed with catalog number SN2010jl in the visible and infrared light ranges for months and first years using the X-Shooter spectrograph.

“When we combined the observational data, we were able to make the first measurement of the absorption of different wavelengths in the dust around the supernova,” Gall explains. “This allowed us to learn more about this dust than was previously known.” Thus, it became possible to study in more detail the various sizes of dust particles and their formation.

Dust in the immediate vicinity of a supernova occurs in two stages. Photo: © ESO/M. Kornmesser

As it turned out, dust particles larger than a thousandth of a millimeter are formed in the dense material around the star relatively quickly. The sizes of these particles are surprisingly large for cosmic dust particles, which makes them resistant to destruction by galactic processes. "Our evidence of large dust particles occurring shortly after a supernova explosion means that there must be a fast and efficient way to form them," adds co-author Jens Hjorth of the University of Copenhagen. "But we don't yet understand exactly how this happens."

However, astronomers already have a theory based on their observations. Based on it, the formation of dust proceeds in 2 stages:

1. The star pushes material into its surrounding space shortly before the explosion. Then comes and spreads the supernova shock wave, behind which a cool and dense shell of gas is created - the environment into which dust particles from the previously ejected material can condense and grow.
2. In the second stage, several hundred days after the supernova explosion, the material that was ejected in the explosion itself is added and an accelerated process of dust formation occurs.

“Recently, astronomers have found a lot of dust in the remnants of supernovae that emerged after the explosion. However, they also found evidence for a small amount of dust that actually originated in the supernova itself. New observations explain how this seeming contradiction can be resolved," concludes Christa Gall.

COSMIC MATTER ON THE EARTH'S SURFACE

Unfortunately, unambiguous criteria for differentiating spacechemical substance from formations close to it in shapeterrestrial origin has not yet been developed. That's whymost researchers prefer to search for spacecal particles in areas remote from industrial centers.For the same reason, the main object of research arespherical particles, and most of the material havingirregular shape, as a rule, falls out of sight.In many cases, only the magnetic fraction is analyzed.spherical particles, for which now there are the mostversatile information.

The most favorable objects for the search for spacewhich dust are deep-sea sediments / due to the low speedsedimentation /, as well as polar ice floes, excellentretaining all the matter settling from the atmosphere. Bothobjects are practically free from industrial pollutionand promising for the purpose of stratification, the study of the distributionof cosmic matter in time and space. Bythe conditions of sedimentation are close to them and the accumulation of salt, the latter are also convenient in that they make it easy to isolatedesired material.

Very promising may be the search for dispersedcosmic matter in peat deposits. It is known that the annual growth of high-moor peatlands isapproximately 3-4 mm per year, and the only sourcemineral nutrition for the vegetation of raised bogs ismatter that falls out of the atmosphere.

Spacedust from deep sea sediments

Peculiar red-colored clays and silts, composed of residualkami of siliceous radiolarians and diatoms, cover 82 million km 2ocean floor, which is one sixth of the surfaceour planet. Their composition according to S.S. Kuznetsov is as follows total:55% SiO 2 ;16% Al 2 O 3 ;9% F eO and 0.04% Ni and So, At a depth of 30-40 cm, teeth of fish, livingin the Tertiary era. This gives grounds to conclude thatsedimentation rate is approximately 4 cm pera million years. From the point of view of terrestrial origin, the compositionclays are difficult to interpret. High contentin them nickel and cobalt is the subject of numerousresearch and is considered to be associated with the introduction of spacematerial / 2,154,160,163,164,179/. Really,nickel clark is 0.008% for the upper horizons of the earthbark and 10 % for sea water /166/.

Extraterrestrial matter found in deep sea sedimentsfor the first time by Murray during the expedition on the Challenger/1873-1876/ /the so-called "Murray space balls"/.Somewhat later, Renard took up their study, as a resultthe result of which was the joint work on the description of the foundmaterial /141/. The discovered space balls belong topressed to two types: metal and silicate. Both typespossessed magnetic properties, which made it possible to applyto isolate them from the sediment magnet.

Spherulla had a regular round shape with an averagewith a diameter of 0.2 mm. In the center of the ball, malleablean iron core covered with an oxide film on top.balls, nickel and cobalt were found, which made it possible to expressassumption about their cosmic origin.

Silicate spherules are usually not have had strict sphereric form / they can be called spheroids /. Their size is somewhat larger than metal ones, the diameter reaches 1 mm . The surface has a scaly structure. mineralogicalcue composition is very uniform: they contain iron-magnesium silicates-olivines and pyroxenes.

Extensive material on the cosmic component of the deep sediments collected by a Swedish expedition on a vessel"Albatross" in 1947-1948. Its participants used the selectionsoil columns to a depth of 15 meters, the study of the obtainedA number of works are devoted to the material / 92,130,160,163,164,168/.The samples were very rich: Petterson points out that1 kg of sediment accounts for from several hundred to several thousand spheres.

All authors note a very uneven distributionballs both along the section of the ocean floor and along itsarea. For example, Hunter and Parkin /121/, having examined twodeep-sea samples from different places in the Atlantic Ocean,found that one of them contains almost 20 times morespherules than the other. They explained this difference by unequalsedimentation rates in different parts of the ocean.

In 1950-1952, the Danish deep-sea expedition usednile to collect cosmic matter in the bottom sediments of the ocean magnetic rake - an oak board with fixed onIt has 63 strong magnets. With the help of this device, about 45,000 m 2 of the surface of the ocean floor were combed.Among the magnetic particles that have a probable cosmicorigin, two groups are distinguished: black balls with metalwith or without personal nuclei and brown balls with crystalpersonal structure; the former are rarely larger than 0.2mm , they are shiny, with a smooth or rough surfaceness. Among them there are fused specimensunequal sizes. Nickel andcobalt, magnetite and schrei-bersite are common in the mineralogical composition.

Balls of the second group have a crystalline structureand are brown. Their average diameter is 0.5 mm . These spherules contain silicon, aluminum and magnesium andhave numerous transparent inclusions of olivine orpyroxenes /86/. The question of the presence of balls in bottom siltsThe Atlantic Ocean is also discussed in /172a/.

Spacedust from soils and sedimentary rocks

Academician Vernadsky wrote that cosmic matter is continuously deposited on our planet.pial opportunity to find it anywhere in the worldsurfaces. This is connected, however, with certain difficulties,which can be led to the following main points:

1. amount of matter deposited per unit areavery little;
2. conditions for the preservation of spherules for a longtime is still insufficiently studied;
3. there is the possibility of industrial and volcanic pollution;
4. it is impossible to exclude the role of the redeposition of the already fallensubstances, as a result of which in some places there will beenrichment is observed, and in others - depletion of cosmic material.

Apparently optimal for the conservation of spacematerial is an oxygen-free environment, smoldering, in particularness, a place in deep-sea basins, in areas of accumuseparation of sedimentary material with rapid disposal of matter,as well as in swamps with a reducing environment. Mostlikely to be enriched in cosmic matter as a result of redeposition in certain areas of river valleys, where a heavy fraction of mineral sediment is usually deposited/ obviously, only that part of the dropped out gets herea substance whose specific gravity is greater than 5/. It is possible thatenrichment with this substance also takes place in the finalmoraines of glaciers, at the bottom of tarns, in glacial pits,where melt water accumulates.

There is information in the literature about finds during the shlikhovspherules related to space /6,44,56/. in the atlasplacer minerals, published by the State Publishing House of Scientific and Technicalliterature in 1961, spherules of this kind are assigned tometeoritic. Of particular interest are the finds of spacesome dust in ancient rocks. The works of this direction arehave recently been very intensively investigated by a number oftel. So, spherical hour types, magnetic, metal

and glassy, ​​the first with the appearance characteristic of meteoritesManstetten figures and high nickel content,described by Shkolnik in the Cretaceous, Miocene and Pleistocenerocks of California /177,176/. Later similar findswere made in the Triassic rocks of northern Germany /191/.Croisier, setting himself the goal of studying the spacecomponent of ancient sedimentary rocks, studied samplesfrom various locations / area of ​​New York, New Mexico, Canada,Texas / and different ages / from Ordovician to Triassic inclusive/. Among the studied samples were limestones, dolomites, clays, shales. The author found spherules everywhere, which obviously cannot be attributed to indus-strial pollution, and most likely have a cosmic nature. Croisier claims that all sedimentary rocks contain cosmic material, and the number of spherules isranges from 28 to 240 per gram. Particle size in mostmost cases, it fits in the range from 3µ to 40µ , andtheir number is inversely proportional to the size /89/.Data on meteor dust in the Cambrian sandstones of Estoniainforms Wiiding /16a/.

As a rule, spherules accompany meteorites and they are foundat impact sites, along with meteorite debris. Previouslyall balls were found on the surface of the Braunau meteorite/3/ and in the craters of Hanbury and Vabar /3/, later similar formations along with a large number of particles of irregularforms found in the vicinity of the Arizona crater /146/.This type of finely dispersed substance, as already mentioned above, is usually referred to as meteorite dust. The latter has been subjected to detailed study in the works of many researchers.providers both in the USSR and abroad /31,34,36,39,77,91,138,146,147,170-171,206/. On the example of the Arizona spherulesit was found that these particles have an average size of 0.5 mmand consist either of kamacite intergrown with goethite, or ofalternating layers of goethite and magnetite covered with thina layer of silicate glass with small inclusions of quartz.The content of nickel and iron in these minerals is characteristicrepresented by the following numbers:

mineral iron nickel
kamacite 72-97% 0,2 - 25%
magnetite 60 - 67% 4 - 7%
goethite 52 - 60% 2-5%

Nininger /146/ found in the Arizona balls of a mineral-ly, characteristic of iron meteorites: cohenite, steatite,schreibersite, troilite. The nickel content was found to beon average,1 7%, which coincides, in general, with the numbers , received-nym Reinhard /171/. It should be noted that the distributionfine meteorite material in the vicinityArizona meteorite crater is very uneven. The probable cause of this is, apparently, either the wind,or an accompanying meteor shower. Mechanismformation of Arizona spherules, according to Reinhardt, consists ofsudden solidification of liquid fine meteoritesubstances. Other authors /135/, along with this, assign a definitiondivided place of condensation formed at the time of the fallvapors. Essentially similar results were obtained in the course of studyingvalues ​​of finely dispersed meteoritic matter in the regionfallout of the Sikhote-Alin meteor shower. E.L. Krinov/35-37.39/ subdivides this substance into the following main categories:

1. micrometeorites with a mass of 0.18 to 0.0003 g, havingregmaglypts and melting bark / should be strictly distinguishedmicrometeorites according to E.L. Krinov from micrometeorites in the understandingWhipple Institute, which was discussed above/;
2. meteor dust - mostly hollow and porousmagnetite particles formed as a result of splashing of meteorite matter in the atmosphere;
3. meteorite dust - a product of crushing falling meteorites, consisting of acute-angled fragments. In mineralogicalthe composition of the latter includes kamacite with an admixture of troilite, schreibersite, and chromite.As in the case of the Arizona meteorite crater, the distributionthe division of matter over the area is uneven.

Krinov considers spherules and other melted particles to be products of meteorite ablation and citesfinds of fragments of the latter with balls stuck to them.

Finds are also known at the site of the fall of a stone meteoriterain Kunashak /177/.

The issue of distribution deserves special discussion.cosmic dust in soils and other natural objectsarea of ​​the fall of the Tunguska meteorite. Great work in thisdirection were carried out in 1958-65 by expeditionsCommittee on Meteorites of the Academy of Sciences of the USSR of the Siberian Branch of the Academy of Sciences of the USSR. It has been established thatin the soils of both the epicenter and places remote from it bydistances up to 400 km or more, are almost constantly detectedmetal and silicate balls ranging in size from 5 to 400 microns.Among them are shiny, matte and roughhour types, regular balls and hollow cones. In somecases, metallic and silicate particles are fused to each otherfriend. According to K.P. Florensky /72/, the soils of the epicentral region/ interfluve Khushma - Kimchu / contain these particles only ina small amount /1-2 per conventional unit of area/.Samples with a similar content of balls are found ondistance up to 70 km from the crash site. Relative povertyThe validity of these samples is explained by K.P. Florenskycircumstance that at the time of the explosion, the bulk of the weatherrita, having passed into a finely dispersed state, was thrown outinto the upper layers of the atmosphere and then drifted in the directionwind. Microscopic particles, settling according to the Stokes law,should have formed a scattering plume in this case.Florensky believes that the southern boundary of the plume is locatedapproximately 70 km to C Z from the meteorite lodge, in the poolChuni river / Mutorai trading post area / where the sample was foundwith the content of space balls up to 90 pieces per conditionalarea unit. In the future, according to the author, the traincontinues to stretch to the northwest, capturing the basin of the Taimura River.Works of the Siberian Branch of the USSR Academy of Sciences in 1964-65. it was found that relatively rich samples are found along the entire course R. Taimur, a also on N. Tunguska / see map-scheme /. The spherules isolated at the same time contain up to 19% nickel / according tomicrospectral analysis carried out at the Institute of Nuclearphysics of the Siberian Branch of the Academy of Sciences of the USSR /. This approximately coincides with the numbersobtained by P.N. Paley in the field on the modelricks isolated from the soils of the area of ​​the Tunguska catastrophe.These data allow us to state that the found particlesare indeed of cosmic origin. The question isabout their relation to the Tunguska meteorite remainswhich is open due to the lack of similar studiesbackground regions, as well as the possible role of processesredeposition and secondary enrichment.

Interesting finds of spherules in the area of ​​the crater on Patomskyhighlands. The origin of this formation, attributedHoop to volcanic, still debatablebecause the presence of a volcanic cone in an area remotemany thousands of kilometers from volcanic foci, ancientthem and modern ones, in many kilometers of sedimentary-metamorphicthicknesses of the Paleozoic, it seems at least strange. Studies of spherules from the crater could give an unambiguousanswer to the question and about its origin / 82,50,53 /.the removal of matter from soils can be carried out by walkinghovaniya. In this way, a fraction of hundreds ofmicron and specific gravity above 5. However, in this casethere is a danger of discarding all the small magnetic frockand most silicate. E.L. Krinov advisesremove magnetic sanding with a magnet suspended from the bottom tray / 37 /.

A more accurate method is magnetic separation, dryor wet, although it also has a significant drawback: induring processing, the silicate fraction is lost. One ofinstallations of dry magnetic separation are described by Reinhardt/171/.

As already mentioned, cosmic matter is often collectednear the surface of the earth, in areas free from industrial pollution. In their direction, these works are close to the search for cosmic matter in the upper horizons of the soil.Trays filled withwater or adhesive solution, and plates lubricatedglycerin. The exposure time can be measured in hours, days,weeks, depending on the purpose of the observations. At the Dunlap Observatory in Canada, the collection of space matter usingadhesive plates have been carried out since 1947 /123/. In lit-The literature describes several variants of methods of this kind.For example, Hodge and Wright /113/ used for a number of yearsfor this purpose, glass slides coated with slowly dryingemulsion and solidification forming a finished preparation of dust;Croisier /90/ used ethylene glycol poured onto trays,which was easily washed with distilled water; in the worksHunter and Parkin /158/ oiled nylon mesh was used.

In all cases, spherical particles were found in the sediment,metal and silicate, most often smaller in size 6 µ in diameter and rarely exceeding 40 µ.

Thus, the totality of the presented dataconfirms the assumption of the fundamental possibilitydetection of cosmic matter in the soil for almostany part of the earth's surface. At the same time, it shouldkeep in mind that the use of soil as an objectto identify the space component is associated with methodologicaldifficulties far greater than those forsnow, ice and, possibly, to bottom silts and peat.

spacesubstance in ice

According to Krinov /37/, the discovery of a cosmic substance in the polar regions is of significant scientific importance.ing, since in this way a sufficient amount of material can be obtained, the study of which will probably approximatesolution of some geophysical and geological issues.

The separation of cosmic matter from snow and ice canbe carried out by various methods, ranging from the collectionlarge fragments of meteorites and ending with the production of meltedwater mineral sediment containing mineral particles.

In 1959 Marshall /135/ suggested an ingenious waystudy of particles from ice, similar to the counting methodred blood cells in the bloodstream. Its essence isIt turns out that to the water obtained by melting the sampleice, an electrolyte is added and the solution is passed through a narrow hole with electrodes on both sides. Atthe passage of a particle, the resistance changes sharply in proportion to its volume. Changes are recorded using specialgod recording device.

It should be borne in mind that ice stratification is nowcarried out in several ways. It is possible thatcomparison of already stratified ice with distributioncosmic matter can open up new approaches tostratification in places where other methods cannot beapplied for one reason or another.

To collect space dust, American Antarcticexpeditions 1950-60 used cores obtained fromdetermination of the thickness of the ice cover by drilling. /1 S3/.Samples with a diameter of about 7 cm were sawn into segments along 30 cm long, melted and filtered. The resulting precipitate was carefully examined under a microscope. Were discoveredparticles of both spherical and irregular shapes, andthe former constituted an insignificant part of the sediment. Further research was limited to spherules, since theycould be more or less confidently attributed to spacecomponent. Among the balls in size from 15 to 180 / hbyparticles of two types were found: black, shiny, strictly spherical and brown transparent.

Detailed study of cosmic particles isolated fromice of Antarctica and Greenland, was undertaken by Hodgeand Wright /116/. In order to avoid industrial pollutionice was taken not from the surface, but from a certain depth -in Antarctica, a 55-year-old layer was used, and in Greenland,750 years ago. Particles were selected for comparison.from the air of Antarctica, which turned out to be similar to glacial ones. All particles fit into 10 classification groupswith a sharp division into spherical particles, metallicand silicate, with and without nickel.

An attempt to obtain space balls from a high mountainsnow was undertaken by Divari /23/. Having melted a significant amountsnow /85 buckets/ taken from the surface of 65 m 2 on the glacierTuyuk-Su in the Tien Shan, however, he did not get what he wantedresults that can be explained or unevencosmic dust falling on the earth's surface, orfeatures of the applied technique.

In general, apparently, the collection of cosmic matter inpolar regions and on high mountain glaciers is oneof the most promising areas of work on space dust.

Sources pollution

There are currently two main sources of materialla, which can imitate in its properties the spacedust: volcanic eruptions and industrial wasteenterprises and transport. It is known what volcanic dust,released into the atmosphere during eruptionsstay there in suspension for months and years.Due to structural features and a small specificweight, this material can be distributed globally, andduring the transfer process, particles are differentiated according toweight, composition and size, which must be taken into account whenspecific analysis of the situation. After the famous eruptionvolcano Krakatau in August 1883, the smallest dust thrown outshennaya to a height of up to 20 km. found in the airfor at least two years /162/. Similar observationsDenias were made during the periods of volcanic eruptions of Mont Pelee/1902/, Katmai /1912/, groups of volcanoes in the Cordillera /1932/,volcano Agung /1963/ /12/. Microscopic dust collectedfrom different areas of volcanic activity, looks likegrains of irregular shape, with curvilinear, broken,jagged contours and relatively rarely spheroidaland spherical with a size from 10µ to 100. The number of sphericalwater is only 0.0001% by weight of the total material/115/. Other authors raise this value to 0.002% /197/.

Particles of volcanic ash have black, red, greenlazy, gray or brown. Sometimes they are colorlesstransparent and glass-like. Generally speaking, in volcanicglass is an essential part of many products. itconfirmed by the data of Hodge and Wright, who found thatparticles with an amount of iron from 5% and above arenear volcanoes only 16% . It should be taken into account that in the processdust transfer occurs, it is differentiated by size andspecific gravity, and large dust particles are eliminated faster Total. As a result, in remote from volcaniccenters, areas are likely to detect only the smallest and light particles.

Spherical particles were subjected to special study.volcanic origin. It has been established that they havemost often eroded surface, shape, roughlyleaning to spherical, but never have elongatednecks, like particles of meteorite origin.It is very significant that they do not have a core composed of pureiron or nickel, like those balls that are consideredspace /115/.

In the mineralogical composition of volcanic balls,a significant role belongs to glass, which has a bubblystructure, and iron-magnesium silicates - olivine and pyroxene. A much smaller part of them is composed of ore minerals - pyri-volume and magnetite, which mostly form disseminatednicks in glass and frame structures.

As for the chemical composition of volcanic dust,an example is the composition of the ashes of Krakatoa.Murray /141/ found in it a high content of aluminum/up to 90%/ and low iron content /not exceeding 10%.It should be noted, however, that Hodge and Wright /115/ could notconfirm Morrey's data on aluminum. Question aboutspherules of volcanic origin are also discussed in/205a/.

Thus, the properties characteristic of volcanicmaterials can be summarized as follows:

1. volcanic ash contains a high percentage of particlesirregular shape and low - spherical,
2. balls of volcanic rock have certain structurestour features - eroded surfaces, the absence of hollow spherules, often blistering,
3. spherules are dominated by porous glass,
4. the percentage of magnetic particles is low,
5. in most cases spherical particle shape imperfect
6. acute-angled particles have sharply angular shapesrestrictions, which allows them to be used asabrasive material.

A very significant danger of imitation of space spheresroll with industrial balls, in large quantitiessteam locomotive, steamship, factory pipes, formed during electric welding, etc. Specialstudies of such objects have shown that a significanta percentage of the latter has the form of spherules. According to Shkolnik /177/,25% industrial products is composed of metal slag.He also gives the following classification of industrial dust:

1. non-metallic balls, irregular shape,
2. balls are hollow, very shiny,
3. balls similar to space, folded metalcal material with the inclusion of glass. Among the latterhaving the greatest distribution, there are drop-shaped,cones, double spherules.

From our point of view, the chemical compositionindustrial dust was studied by Hodge and Wright /115/.It was found that the characteristic features of its chemical compositionis a high content of iron and in most cases - the absence of nickel. It must be borne in mind, however, that neitherone of the indicated signs cannot serve as an absolutecriterion of difference, especially since the chemical composition of differenttypes of industrial dust can be varied, andforesee the appearance of one or another variety ofindustrial spherules is almost impossible. Therefore, the best a guarantee against confusion can serve at the modern levelknowledge is only sampling in remote "sterile" fromindustrial pollution areas. degree of industrialpollution, as shown by special studies, isin direct proportion to the distance to settlements.Parkin and Hunter in 1959 made observations as far as possible.transportability of industrial spherules with water /159/.Although balls with a diameter of more than 300µ flew out of the factory pipes, in a water basin located 60 miles from the cityyes, in the direction of the prevailing winds, onlysingle copies of 30-60 in size, the number of copies isa ditch measuring 5-10µ was, however, significant. Hodge andWright /115/ showed that in the vicinity of the Yale observatory,near the city center, fell on 1cm 2 surfaces per dayup to 100 balls over 5µ in diameter. Them the amount doubleddecreased on Sundays and fell 4 times at a distance10 miles from the city. So in remote areasprobably industrial pollution only with balls of diameter rum less than 5 µ .

It must be taken into account that in recent20 years there is a real danger of food pollutionnuclear explosions" that can supply spherules to the globalnominal scale /90.115/. These products are different from yes like-ny radioactivity and the presence of specific isotopes -strontium - 89 and strontium - 90.

Finally, keep in mind that some pollutionatmosphere with products similar to meteor and meteoritedust, can be caused by combustion in the Earth's atmosphereartificial satellites and launch vehicles. Phenomena observedin this case, are very similar to what takes place whenfalling fireballs. Serious danger to scientific researchions of cosmic matter are irresponsibleexperiments implemented and planned abroad withlaunch into near-Earth spacePersian substance of artificial origin.

The formand physical properties of cosmic dust

Shape, specific gravity, color, luster, brittleness and other physicalThe cosmic properties of cosmic dust found in various objects have been studied by a number of authors. Some-ry researchers proposed schemes for the classification of spacecal dust based on its morphology and physical properties.Although a single unified system has not yet been developed,It seems, however, appropriate to cite some of them.

Baddhyu /1950/ /87/ on the basis of purely morphologicalsigns divided the terrestrial matter into the following 7 groups:

1. irregular gray amorphous fragments of size 100-200µ.
2. slag-like or ash-like particles,
3. rounded grains, similar to fine black sand/magnetite/,
4. smooth black shiny balls with an average diameter 20µ .
5. large black balls, less shiny, often roughrough, rarely exceeding 100 µ in diameter,
6. silicate balls from white to black, sometimeswith gas inclusions
7. dissimilar balls, consisting of metal and glass,20µ in size on average.

The whole variety of types of cosmic particles, however, is notis exhausted, apparently, by the listed groups.So, Hunter and Parkin /158/ found roundedflattened particles, apparently of cosmic origin which cannot be attributed to any of the transfersnumerical classes.

Of all the groups described above, the most accessible toidentification by appearance 4-7, shaped like regular balls.

E.L. Krinov, studying the dust collected in the Sikhote-Alinsky's fall, distinguished in its composition the wrongin the form of fragments, balls and hollow cones /39/.

Typical shapes of space balls are shown in Fig.2.

A number of authors classify cosmic matter according tosets of physical and morphological properties. By destinyto a certain weight, cosmic matter is usually divided into 3 groups/86/:

1. metallic, consisting mainly of iron,with a specific gravity greater than 5 g/cm 3 .
2. silicate - transparent glass particles with specificweighing approximately 3 g / cm 3
3. heterogeneous: metal particles with glass inclusions and glass particles with magnetic inclusions.

Most researchers remain within thisrough classification, limited to only the most obviousfeatures of difference. However, those who deal withparticles extracted from the air, another group is distinguished -porous, brittle, with a density of about 0.1 g/cm 3 /129/. Toit includes particles of meteor showers and most bright sporadic meteors.

A rather thorough classification of the particles foundin the Antarctic and Greenland ice, as well as capturedfrom the air, given by Hodge and Wright and presented in the scheme / 205 /:

1. black or dark gray dull metal balls,pitted, sometimes hollow;
2. black, glassy, ​​highly refractive balls;
3. light, white or coral, glassy, ​​smooth,sometimes translucent spherules;
4. particles of irregular shape, black, shiny, brittle,granular, metallic;
5. irregularly shaped reddish or orange, dull,uneven particles;
6. irregular shape, pinkish-orange, dull;
7. irregular shape, silvery, shiny and dull;
8. irregular shape, multi-colored, brown, yellow, green, black;
9. irregular shape, transparent, sometimes green orblue, glassy, ​​smooth, with sharp edges;
10. spheroids.

Although the classification of Hodge and Wright seems to be the most complete, there are still particles that, judging by the descriptions of various authors, are difficult to classifyback to one of the named groups. So, it is not uncommon to meetelongated particles, balls sticking together with each other, balls,having various growths on their surface /39/.

On the surface of some spherules in a detailed studyfigures are found that are similar to Widmanstätten, observedin iron-nickel meteorites / 176/.

The internal structure of the spherules does not differ muchimage. Based on this feature, the following 4 groups:

1. hollow spherules / meet with meteorites /,
2. metal spherules with a core and an oxidized shell/ in the core, as a rule, nickel and cobalt are concentrated,and in the shell - iron and magnesium /,
3. oxidized balls of uniform composition,
4. silicate balls, most often homogeneous, with flakythat surface, with metal and gas inclusions/ the latter give them the appearance of slag or even foam /.

As for particle sizes, there is no firmly established division on this basis, and each authoradheres to its classification depending on the specifics of the material available. The largest of the described spherules,found in deep-sea sediments by Brown and Pauli /86/ in 1955, hardly exceed 1.5 mm in diameter. itclose to the existing limit found by Epic /153/:

where r is the radius of the particle, σ - surface tensionmelt, ρ is the air density, and v is the speed of the drop. Radius

particle cannot exceed the known limit, otherwise the dropbreaks down into smaller ones.

The lower limit, in all likelihood, is not limited, which follows from the formula and is justified in practice, becauseas the techniques improve, the authors operate on allsmaller particles. Most researchers are limitedcheck the lower limit of 10-15µ /160-168,189/.At the same time, studies of particles with a diameter of up to 5 µ started /89/ and 3 µ /115-116/, and Hemenway, Fulman and Phillips operateparticles up to 0.2 / µ and less in diameter, highlighting them in particularthe former class of nanometeorites / 108 /.

The average diameter of cosmic dust particles is taken equal to 40-50 µ . As a result of intensive study of spacewhich substances from the atmosphere Japanese authors found that 70% of the entire material are particles less than 15 µ in diameter.

A number of works /27,89,130,189/ contain a statement aboutthat the distribution of balls depending on their massand the dimensions obey the following pattern:

V 1 N 1 \u003d V 2 N 2

where v - mass of the ball, N - number of balls in a given groupResults that satisfactorily agree with the theoretical ones were obtained by a number of researchers working with the spacematerial isolated from various objects / for example, Antarctic ice, deep sea sediments, materials,obtained as a result of satellite observations/.

Of fundamental interest is the question of whetherto what extent the properties of nyli changed over the course of geological history. Unfortunately, the currently accumulated material does not allow us to give an unambiguous answer, however,Shkolnik's message /176/ about the classification lives onspherules isolated from the Miocene sedimentary rocks of California. The author divided these particles into 4 categories:

1/ black, strongly and weakly magnetic, solid or with cores consisting of iron or nickel with an oxidized shellwhich is made of silica with an admixture of iron and titanium. These particles may be hollow. Their surface is intensely shiny, polished, in some cases rough or iridescent as a result of light reflection from saucer-shaped depressions on their surfaces

2/ gray-steel or bluish-gray, hollow, thinwall, very fragile spherules; contain nickel, havepolished or polished surface;

3/ brittle balls containing numerous inclusionsgray steel metallic and black non-metallicmaterial; microscopic bubbles in their walls ki / this group of particles is the most numerous /;

4/ brown or black silicate spherules, non-magnetic.

It is easy to replace that the first group according to Shkolnikcorresponds closely to Buddhue's 4 and 5 particle groups. Bamong these particles there are hollow spherules similar tothose found in meteorite impact areas.

Although these data do not contain exhaustive informationon the issue raised, it seems possible to expressin the first approximation, the opinion that morphology and physi-physical properties of at least some groups of particlesof cosmic origin, falling on the Earth, do notsang significant evolution over the availablegeological study of the period of the planet's development.

Chemicalcomposition of space dust.

The study of the chemical composition of cosmic dust occurswith certain difficulties of principle and technicalcharacter. Already on my own small size of the studied particles,the difficulty of obtaining in any significant quantitiesvakh create significant obstacles to the application of techniques that are widely used in analytical chemistry. Further,it must be borne in mind that the samples under study in the vast majority of cases may contain impurities, and sometimesvery significant, earthly material. Thus, the problem of studying the chemical composition of cosmic dust is intertwinedlurks with the question of its differentiation from terrestrial impurities.Finally, the very formulation of the question of the differentiation of the "terrestrial"and "cosmic" matter is to some extent conditional, because The earth and all its components, its constituents,represent, ultimately, also a cosmic object, andtherefore, strictly speaking, it would be more correct to pose the questionabout finding signs of difference between different categoriescosmic matter. It follows from this that the similarityentities of terrestrial and extraterrestrial origin can, in principle,extend very far, which creates additionaldifficulties for studying the chemical composition of cosmic dust.

However, in recent years, science has been enriched by a number ofmethodological techniques that allow, to a certain extent, to overcomeovercome or bypass obstacles that arise. Development but-the latest methods of radiation chemistry, X-ray diffractionmicroanalysis, the improvement of microspectral techniques now make it possible to investigate insignificant in their own waythe size of the objects. Currently quite affordableanalysis of the chemical composition of not only individual particles ofmic dust, but also the same particle in different its sections.

In the last decade, a significant numberworks devoted to the study of the chemical composition of spacedust from various sources. For reasonswhich we have already touched upon above, the study was mainly carried out by spherical particles related to magneticfraction of dust, As well as in relation to the characteristics of physicalproperties, our knowledge of the chemical composition of acute-angledmaterial is still quite scarce.

Analyzing the materials received in this direction by a wholea number of authors, one should come to the conclusion that, firstly,the same elements are found in cosmic dust as inother objects of terrestrial and cosmic origin, for example, it contains Fe, Si, Mg .In some cases - rarelyland elements and Ag the findings are doubtful /, in relation toThere are no reliable data in the literature. Secondly, allthe amount of cosmic dust that falls on Earthbe divided by chemical composition into at least tri large groups of particles:

a) metal particles with a high content Fe and N i ,
b) particles of predominantly silicate composition,
c) particles of mixed chemical nature.

It is easy to see that the three groups listedessentially coincide with the accepted classification of meteorites, whichrefers to a close, and perhaps a common source of origincirculation of both types of cosmic matter. It can be noted dFurther, there is a large variety of particles within each of the groups under consideration. This gives rise to a number of researchersher to divide cosmic dust by chemical composition by 5.6 andmore groups. Thus, Hodge and Wright single out the following eighttypes of basic particles that differ from each other as much as possiblerphological features, and chemical composition:

1. iron balls containing nickel,
2. iron spherules, in which nickel is not found,
3. silica balls,
4. other spheres,
5. irregularly shaped particles with a high content of iron and nickel;
6. the same without the presence of any significant quantities estv nickel,
7. silicate particles of irregular shape,
8. other particles of irregular shape.

From the above classification it follows, among other things,that circumstance that the presence of a high nickel content in the material under study cannot be recognized as a mandatory criterion for its cosmic origin. So, it meansThe main part of the material extracted from the ice of Antarctica and Greenland, collected from the air of the highlands of New Mexico, and even from the area where the Sikhote-Alin meteorite fell, did not contain quantities available for determination.nickel. At the same time, one has to take into account the well-founded opinion of Hodge and Wright that a high percentage of nickel (up to 20% in some cases) is the onlyreliable criterion of the cosmic origin of a particular particle. Obviously, in case of his absence, the researchershould not be guided by the search for "absolute" criteria"and on the assessment of the properties of the material under study, taken in their aggregates.

In many works, the heterogeneity of the chemical composition of even the same particle of space material in its different parts is noted. So it was established that nickel tends to the core of spherical particles, cobalt is also found there.The outer shell of the ball is composed of iron and its oxide.Some authors admit that nickel exists in the formindividual spots in the magnetite substrate. Below we presentdigital materials characterizing the average contentnickel in dust of cosmic and terrestrial origin.

From the table it follows that the analysis of the quantitative contentnickel can be useful in differentiatingspace dust from volcanic.

From the same point of view, the relations N i : Fe ; Ni : co, Ni : Cu , which are sufficientlyare constant for individual objects of the terrestrial and space origin.

igneous rocks-3,5 1,1

When differentiating cosmic dust from volcanicand industrial pollution can be of some benefitalso provide a study of the quantitative content Al and K , which are rich in volcanic products, and Ti and V being frequent companions Fe in industrial dust.It is significant that in some cases industrial dust may contain a high percentage of N i . Therefore, the criterion for distinguishing some types of cosmic dust fromterrestrial should serve not just a high content of N i , a high N content i together with Co and C u/88.121, 154.178.179/.

Information about the presence of radioactive products of cosmic dust is extremely scarce. Negative results are reportedtatah testing space dust for radioactivity, whichseems doubtful in view of the systematic bombingdust particles located in interplanetary spacesve, cosmic rays. Recall that the productscosmic radiation have been repeatedly detected in meteorites.

Dynamicscosmic dust fallout over time

According to the hypothesis Paneth /156/, fallout of meteoritesdid not take place in distant geological epochs / earlierQuaternary time /. If this view is correct, thenit should also extend to cosmic dust, or at leastwould be on that part of it, which we call meteorite dust.

The main argument in favor of the hypothesis was the absenceimpact of finds of meteorites in ancient rocks, at presenttime, however, there are a number of finds like meteorites,and the cosmic dust component in geologicalformations of rather ancient age / 44,92,122,134,176-177/, Many of the listed sources are citedabove, it should be added that March /142/ discovered balls,apparently of cosmic origin in the Siluriansalts, and Croisier /89/ found them even in the Ordovician.

The distribution of spherules along the section in deep-sea sediments was studied by Petterson and Rothschi /160/, who foundlived that nickel is unevenly distributed over the section, whichexplained, in their opinion, by cosmic causes. Laterfound to be richest in cosmic materialthe youngest layers of bottom silts, which, apparently, is associatedwith the gradual processes of destruction of spacewhom substances. In this regard, it is natural to assumethe idea of ​​a gradual decrease in the concentration of cosmicsubstances down the cut. Unfortunately, in the literature available to us, we did not find sufficiently convincing data on suchkind, the available reports are fragmentary. So, Shkolnik /176/found an increased concentration of balls in the weathering zoneof Cretaceous deposits, from this fact he wasa reasonable conclusion was made that spherules, apparently,can withstand sufficiently harsh conditions if theycould survive lateritization.

Modern regular studies of space falloutdust show that its intensity varies significantly day by day /158/.

Apparently, there is a certain seasonal dynamics /128,135/, and the maximum intensity of precipitationfalls in August-September, which is associated with meteorstreams /78,139/,

It should be noted that meteor showers are not the onlynaya cause of massive fallout of cosmic dust.

There is a theory that meteor showers cause precipitation /82/, meteor particles in this case are condensation nuclei /129/. Some authors suggestThey claim to collect cosmic dust from rainwater and offer their devices for this purpose /194/.

Bowen /84/ found that the peak of precipitation is latefrom the maximum meteor activity by about 30 days, which can be seen from the following table.

These data, although not universally accepted, arethey deserve some attention. Bowen's findings confirmdata on the material of Western Siberia Lazarev /41/.

Although the question of the seasonal dynamics of cosmicdust and its connection with meteor showers is not completely clear.resolved, there are good reasons to believe that such a regularity takes place. So, Croisier / CO /, based onfive years of systematic observations, suggests that two maxima of cosmic dust fallout,that took place in the summer of 1957 and 1959 correlate with the meteormi streams. Summer high confirmed by Morikubo, seasonaldependence was also noted by Marshall and Craken /135,128/.It should be noted that not all authors are inclined to attribute theseasonal dependence due to meteor activity/for example, Brier, 85/.

With regard to the distribution curve of daily depositionmeteor dust, it is apparently strongly distorted by the influence of winds. This is reported, in particular, by Kizilermak andCroisier /126.90/. Good summary of materials on thisReinhardt has a question /169/.

Distributionspace dust on the earth's surface

The question of the distribution of cosmic matter on the surfaceof the Earth, like a number of others, was developed completely insufficientlyexactly. Opinions as well as factual material reportedby various researchers are very contradictory and incomplete.One of the leading experts in this field, Petterson,definitely expressed the opinion that cosmic matterdistributed on the surface of the Earth is extremely uneven / 163 /. Ethis, however, comes into conflict with a number of experimentaldata. In particular, de Jaeger /123/, based on feesof cosmic dust produced using sticky plates in the area of ​​the Canadian Dunlap Observatory, claims that cosmic matter is distributed fairly evenly over large areas. A similar opinion was expressed by Hunter and Parkin /121/ on the basis of a study of cosmic matter in the bottom sediments of the Atlantic Ocean. Hodya /113/ carried out studies of cosmic dust at three remote points from each other. Observations were carried out for a long time, for a whole year. Analysis of the results obtained showed the same rate of accumulation of matter at all three points, and on average, about 1.1 spherules fell per 1 cm 2 per day.about three microns in size. Research in this direction were continued in 1956-56. Hodge and Wildt /114/. On thethis time the collection was carried out in areas separated from each otherfriend over very long distances: in California, Alaska,In Canada. Calculated the average number of spherules , fallen on a unit surface, which turned out to be 1.0 in California, 1.2 in Alaska and 1.1 spherical particles in Canada molds per 1 cm 2 per day. Size distribution of spheruleswas approximately the same for all three points, and 70% were formations with a diameter of less than 6 microns, the numberparticles larger than 9 microns in diameter were small.

It can be assumed that, apparently, the fallout of the cosmicdust reaches the Earth, in general, quite evenly, against this background, certain deviations from the general rule can be observed. So, one can expect the presence of a certain latitudinalthe effect of precipitation of magnetic particles with a tendency to concentrationtions of the latter in the polar regions. Further, it is known thatconcentration of finely dispersed cosmic matter canbe elevated in areas where large meteorite masses fall/ Arizona meteor crater, Sikhote-Alin meteorite,possibly the area where the Tunguska cosmic body fell.

Primary uniformity can, however, in the futuresignificantly disrupted as a result of the secondary redistributionfission of matter, and in some places it may have itaccumulation, and in others - a decrease in its concentration. In general, this issue has been developed very poorly, however, preliminarysolid data obtained by the expedition K M ET AS USSR /head K.P.Florensky/ / 72/ let's talk aboutthat, at least in a number of cases, the content of spacechemical substance in the soil can fluctuate over a wide range lah.

Migratzand Ispacesubstancesinbiogenosfere

No matter how contradictory estimates of the total number of spaceof the chemical substance that falls annually on the Earth, it is possible withcertainty to say one thing: it is measured by many hundredsthousand, and perhaps even millions of tons. Absolutelyit is obvious that this huge mass of matter is included in the farthe most complex chain of processes of the circulation of matter in nature, which constantly takes place within the framework of our planet.Cosmic matter will stop, thus the compositepart of our planet, in the literal sense - the substance of the earth,which is one of the possible channels of influence of spacesome environment on the biogenosphere. It is from these positions that the problemspace dust interested the founder of modernbiogeochemistry ac. Vernadsky. Unfortunately, work in thisdirection, in essence, has not yet begun in earnest. Thereforewe have to confine ourselves to stating a fewfacts that appear to be relevant to thequestion. There are a number of indications that deep-seasediments removed from sources of material drift and havinglow rate of accumulation, relatively rich, Co and Si.Many researchers attribute these elements to cosmicsome origin. Apparently, different types of particles are cos-The chemical dusts are included in the cycle of substances in nature at different rates. Some types of particles are very conservative in this regard, as evidenced by the findings of magnetite spherules in ancient sedimentary rocks.The number of particles can, obviously, depend not only on theirnature, but also on environmental conditions, in particular,its pH value. It is highly likely that the elementsfalling to Earth as part of cosmic dust, canfurther included in the composition of plant and animalorganisms that inhabit the earth. In favor of this assumptionsay, in particular, some data on the chemical compositionve vegetation in the area where the Tunguska meteorite fell.All this, however, is only the first outline,the first attempts at an approach not so much to a solution as toposing the question in this plane.

Recently there has been a trend towards more estimates of the probable mass of the falling cosmic dust. Fromefficient researchers estimate it at 2.4109 tons /107a/.

prospectsstudy of cosmic dust

Everything that has been said in the previous sections of the work,allows you to say with sufficient reason about two things:firstly, that the study of cosmic dust is seriouslyjust beginning and, secondly, that the work in this sectionscience turns out to be extremely fruitful for solvingmany questions of theory / in the future, maybe forpractices/. A researcher working in this area is attractedfirst of all, a huge variety of problems, one way or anotherotherwise related to the clarification of relationships in the system Earth is space.

How it seems to us that the further development of the doctrine ofcosmic dust should go mainly through the following main directions:

1. The study of the near-Earth dust cloud, its spacenatural location, properties of dust particles enteringin its composition, sources and ways of its replenishment and loss,interaction with radiation belts. These studiescan be carried out in full with the help of missiles,artificial satellites, and later - interplanetaryships and automatic interplanetary stations.
2. Of undoubted interest for geophysics is the spacechesky dust penetrating into the atmosphere at altitude 80-120 km, in in particular, its role in the mechanism of emergence and developmentphenomena such as the glow of the night sky, the change in polaritydaylight fluctuations, transparency fluctuations atmosphere, development of noctilucent clouds and bright Hoffmeister bands,dawn and twilight phenomena, meteor phenomena in atmosphere Earth. Special of interest is the study of the degree of correlationlation between the phenomena listed. Unexpected Aspects
cosmic influences can be revealed, apparently, infurther study of the relationship of processes that haveplace in the lower layers of the atmosphere - the troposphere, with penetrationniem in the last cosmic matter. The most seriousAttention should be given to testing Bowen's conjecture aboutconnection of precipitation with meteor showers.
3. Of undoubted interest to geochemists isstudy of the distribution of cosmic matter on the surfaceEarth, the influence on this process of specific geographical,climatic, geophysical and other conditions peculiar to
one or another region of the world. So far completelythe question of the influence of the Earth's magnetic field on the processaccumulation of cosmic matter, meanwhile, in this area,likely to be interesting finds, especiallyif we build studies taking into account paleomagnetic data.
4. Of fundamental interest for both astronomers and geophysicists, not to mention generalist cosmogonists,has a question about meteor activity in remote geologicalepochs. Materials that will be received during this
works, can probably be used in the futurein order to develop additional methods of stratificationbottom, glacial and silent sedimentary deposits.
5. An important area of ​​work is the studymorphological, physical, chemical properties of spacecomponent of terrestrial precipitation, development of methods for distinguishing braidsmic dust from volcanic and industrial, researchisotopic composition of cosmic dust.
6.Search for organic compounds in space dust.It seems likely that the study of cosmic dust will contribute to the solution of the following theoretical problems. questions:

1. The study of the process of evolution of cosmic bodies, in particularness, the Earth and the solar system as a whole.
2. The study of the movement, distribution and exchange of spacematter in the solar system and galaxy.
3. Elucidation of the role of galactic matter in the solar system.
4. The study of orbits and velocities of space bodies.
5. Development of the theory of interaction of cosmic bodies with the earth.
6. Deciphering the mechanism of a number of geophysical processesin the Earth's atmosphere, undoubtedly associated with space phenomena.
7. The study of possible ways of cosmic influences onbiogenosphere of the Earth and other planets.

It goes without saying that the development of even those problemswhich are listed above, but they are far from being exhausted.the whole complex of issues related to cosmic dust,is possible only under the condition of a broad integration and unificationthe efforts of specialists of various profiles.

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space x-ray background

Oscillations and waves: Characteristics of various oscillatory systems (oscillators).

Breaking the Universe

Dusty circumplanetary complexes: fig4

Space dust properties

S. V. Bozhokin St. Petersburg State Technical University	Content

Introduction

Many people admire with delight the beautiful spectacle of the starry sky, one of the greatest creations of nature. In the clear autumn sky, it is clearly visible how a faintly luminous band called the Milky Way runs across the entire sky, having irregular outlines with different widths and brightness. If we look at the Milky Way, which forms our Galaxy, through a telescope, it turns out that this bright band breaks up into many faintly luminous stars, which, to the naked eye, merge into a continuous radiance. It is now established that the Milky Way consists not only of stars and star clusters, but also of gas and dust clouds.

Huge interstellar clouds from luminous rarefied gases got the name gaseous diffuse nebulae. One of the most famous is the nebula in constellation Orion, which is visible even to the naked eye near the middle of the three stars that form the "sword" of Orion. The gases that form it glow with a cold light, reradiating the light of neighboring hot stars. Gaseous diffuse nebulae are mainly composed of hydrogen, oxygen, helium, and nitrogen. Such gaseous or diffuse nebulae serve as a cradle for young stars, which are born in the same way as ours was once born. solar system. The process of star formation is continuous, and stars continue to form today.

AT interstellar space diffuse dusty nebulae are also observed. These clouds are made up of tiny hard dust particles. If a bright star appears near the dusty nebula, then its light is scattered by this nebula and the dusty nebula becomes directly observable(Fig. 1). Gas and dust nebulae can generally absorb the light of the stars lying behind them, so they are often visible in sky shots as gaping black holes against the background of the Milky Way. Such nebulae are called dark nebulae. In the sky of the southern hemisphere there is one very large dark nebula, which the sailors called the Coal Sack. There is no clear boundary between gaseous and dusty nebulae, so they are often observed together as gaseous and dusty nebulae.

Diffuse nebulae are only densifications in that extremely rarefied interstellar matter, which was named interstellar gas. Interstellar gas is detected only when observing the spectra of distant stars, causing additional ones in them. After all, over a long distance, even such a rarefied gas can absorb the radiation of stars. The emergence and rapid development radio astronomy made it possible to detect this invisible gas by the radio waves that it emits. Huge dark clouds of interstellar gas are made up mostly of hydrogen, which even at low temperatures emits radio waves at a length of 21 cm. These radio waves pass unhindered through gas and dust. It was radio astronomy that helped us in studying the shape of the Milky Way. Today we know that gas and dust, mixed with large clusters of stars, form a spiral, the branches of which, leaving the center of the Galaxy, wrap around its middle, creating something similar to a cuttlefish with long tentacles caught in a whirlpool.

At present, a huge amount of matter in our Galaxy is in the form of gas and dust nebulae. Interstellar diffuse matter is concentrated in a relatively thin layer in equatorial plane our star system. Clouds of interstellar gas and dust block the center of the Galaxy from us. Because of the clouds of cosmic dust, tens of thousands of open star clusters remain invisible to us. Fine cosmic dust not only weakens the light of stars, but also distorts them spectral composition. The fact is that when light radiation passes through cosmic dust, it not only weakens, but also changes color. The absorption of light by cosmic dust depends on the wavelength, so from all optical spectrum of a star blue rays are absorbed more strongly and photons corresponding to red color are absorbed weaker. This effect leads to the reddening of the light of stars that have passed through the interstellar medium.

For astrophysicists, the study of the properties of cosmic dust and the elucidation of the influence that this dust has on the study of space is of great importance. physical characteristics of astrophysical objects. Interstellar extinction and interstellar polarization of light, infrared radiation of neutral hydrogen regions, deficit chemical elements in the interstellar medium, questions of the formation of molecules and the birth of stars - in all these problems a huge role belongs to cosmic dust, the properties of which are considered in this article.

Origin of cosmic dust

Cosmic dust grains arise mainly in the slowly expiring atmospheres of stars - red dwarfs, as well as during explosive processes on stars and rapid ejection of gas from the nuclei of galaxies. Other sources of cosmic dust formation are planetary and protostellar nebulae , stellar atmospheres and interstellar clouds. In all processes of formation of cosmic dust particles, the gas temperature drops as the gas moves outward and at some point passes through the dew point, at which vapor condensation that form the nuclei of dust particles. The centers for the formation of a new phase are usually clusters. Clusters are small groups of atoms or molecules that form a stable quasi-molecule. In collisions with an already formed dust grain nucleus, atoms and molecules can join it, either by entering into chemical reactions with dust grain atoms (chemisorption) or completing the forming cluster. In the densest parts of the interstellar medium, the concentration of particles in which is cm -3, the growth of a dust grain can be associated with coagulation processes, in which dust grains can stick together without being destroyed. Coagulation processes, which depend on the properties of the surface of dust grains and their temperatures, occur only when collisions between dust grains occur at low relative collision velocities.

On fig. Figure 2 shows the growth of cosmic dust clusters by adding monomers. The resulting amorphous cosmic dust grain can be a cluster of atoms with fractal properties. fractals called geometric objects: lines, surfaces, spatial bodies that have a strongly indented shape and have the property of self-similarity. self-similarity means the invariance of the main geometric characteristics fractal object when changing the scale. For example, images of many fractal objects turn out to be very similar when the resolution is increased in a microscope. Fractal clusters are highly branched porous structures formed under highly nonequilibrium conditions when solid particles of similar sizes combine into a single whole. Under terrestrial conditions, fractal aggregates are obtained when vapor relaxation metals in non-equilibrium conditions, during the formation of gels in solutions, during the coagulation of particles in fumes. The model of a fractal cosmic dust grain is shown in fig. 3. Note that the processes of dust grain coagulation occurring in protostellar clouds and gas and dust disks, increase significantly with turbulent motion interstellar matter.

The nuclei of cosmic dust particles, consisting of refractory elements, hundredths of a micron in size, are formed in the shells of cold stars during a smooth outflow of gas or during explosive processes. Such nuclei of dust grains are resistant to many external influences.

Cosmic dust on Earth is most often found in certain layers of the ocean floor, ice sheets of the polar regions of the planet, peat deposits, hard-to-reach places in the desert and meteorite craters. The size of this substance is less than 200 nm, which makes its study problematic.

Usually the concept of cosmic dust includes the delimitation of the interstellar and interplanetary varieties. However, all this is very conditional. The most convenient option for studying this phenomenon is the study of dust from space at the edges of the solar system or beyond.

The reason for this problematic approach to the study of the object is that the properties of extraterrestrial dust change dramatically when it is near a star such as the Sun.

Theories on the origin of cosmic dust

Streams of cosmic dust constantly attack the surface of the Earth. The question arises where this substance comes from. Its origin gives rise to many discussions among specialists in this field.

There are such theories of the formation of cosmic dust:

• Decay of celestial bodies. Some scientists believe that space dust is nothing more than the result of the destruction of asteroids, comets and meteorites.
• The remnants of a protoplanetary type cloud. There is a version according to which cosmic dust is referred to as microparticles of a protoplanetary cloud. However, such an assumption raises some doubts due to the fragility of a finely dispersed substance.
• The result of the explosion on the stars. As a result of this process, according to some experts, there is a powerful release of energy and gas, which leads to the formation of cosmic dust.
• Residual phenomena after the formation of new planets. The so-called construction "garbage" has become the basis for the occurrence of dust.

According to some studies, a certain part of the cosmic dust component predated the formation of the solar system, which makes this material even more interesting for further study. It is worth paying attention to this when evaluating and analyzing such an extraterrestrial phenomenon.

The main types of cosmic dust

There is currently no specific classification of cosmic dust types. Subspecies can be distinguished by visual characteristics and location of these microparticles.

Consider seven groups of cosmic dust in the atmosphere, different in external indicators:

1. Gray fragments of irregular shape. These are residual phenomena after the collision of meteorites, comets and asteroids no larger than 100-200 nm in size.
2. Particles of slag-like and ash-like formation. Such objects are difficult to identify solely by external signs, because they have undergone changes after passing through the Earth's atmosphere.
3. The grains are round in shape, which are similar in parameters to black sand. Outwardly, they resemble powder of magnetite (magnetic iron ore).
4. Small black circles with a characteristic sheen. Their diameter does not exceed 20 nm, which makes their study a painstaking task.
5. Larger balls of the same color with a rough surface. Their size reaches 100 nm and makes it possible to study their composition in detail.
6. Balls of a certain color with a predominance of black and white tones with inclusions of gas. These microparticles of cosmic origin consist of a silicate base.
7. Spheres of heterogeneous structure made of glass and metal. Such elements are characterized by microscopic dimensions within 20 nm.

According to the astronomical location, 5 groups of cosmic dust are distinguished:

• Dust found in intergalactic space. This type can distort the size of distances in certain calculations and is able to change the color of space objects.
• Formations within the Galaxy. The space within these limits is always filled with dust from the destruction of cosmic bodies.
• Matter concentrated between stars. It is most interesting due to the presence of a shell and a core of a solid consistency.
• Dust located near a certain planet. It is usually located in the ring system of a celestial body.
• Clouds of dust around the stars. They circle the orbital path of the star itself, reflecting its light and creating a nebula.

Three groups according to the total specific gravity of microparticles look like this:

1. metal group. Representatives of this subspecies have a specific gravity of more than five grams per cubic centimeter, and their basis consists mainly of iron.
2. silicate group. The base is clear glass with a specific gravity of approximately three grams per cubic centimeter.
3. Mixed group. The very name of this association indicates the presence of both glass and iron in the structure of microparticles. The base also includes magnetic elements.

Four groups according to the similarity of the internal structure of cosmic dust microparticles:

• Spherules with hollow filling. This species is often found in places where meteorites fall.
• Spherules of metal formation. This subspecies has a core of cobalt and nickel, as well as a shell that has oxidized.
• Spheres of uniform addition. Such grains have an oxidized shell.
• Balls with a silicate base. The presence of gas inclusions gives them the appearance of ordinary slags, and sometimes foam.

It should be remembered that these classifications are very arbitrary, but they serve as a certain guideline for designating types of dust from space.

Composition and characteristics of the components of cosmic dust

Let's take a closer look at what cosmic dust is made of. There is a problem in determining the composition of these microparticles. Unlike gaseous substances, solids have a continuous spectrum with relatively few bands that are blurred. As a result, the identification of cosmic dust grains is difficult.

The composition of cosmic dust can be considered on the example of the main models of this substance. These include the following subspecies:

1. Ice particles, the structure of which includes a core with a refractory characteristic. The shell of such a model consists of light elements. In particles of large size there are atoms with elements of magnetic properties.
2. Model MRN, the composition of which is determined by the presence of silicate and graphite inclusions.
3. Oxide space dust, which is based on diatomic oxides of magnesium, iron, calcium and silicon.

General classification according to the chemical composition of cosmic dust:

• Balls with a metallic nature of education. The composition of such microparticles includes such an element as nickel.
• Metal balls with the presence of iron and the absence of nickel.
• Circles on a silicone basis.
• Irregular-shaped iron-nickel balls.

More specifically, you can consider the composition of cosmic dust on the example found in oceanic silt, sedimentary rocks and glaciers. Their formula will differ little from one another. Findings in the study of the seabed are balls with a silicate and metal base with the presence of such chemical elements as nickel and cobalt. Also, microparticles with the presence of aluminum, silicon and magnesium were found in the bowels of the water element.

Soils are fertile for the presence of cosmic material. A particularly large number of spherules were found in the places where meteorites fell. They were based on nickel and iron, as well as various minerals such as troilite, cohenite, steatite and other components.

Glaciers also hide aliens from outer space in the form of dust in their blocks. Silicate, iron and nickel serve as the basis for the found spherules. All mined particles were classified into 10 clearly demarcated groups.

Difficulties in determining the composition of the studied object and differentiating it from impurities of terrestrial origin leave this issue open for further research.

The influence of cosmic dust on life processes

The influence of this substance has not been fully studied by specialists, which provides great opportunities in terms of further activities in this direction. At a certain height, using rockets, they discovered a specific belt consisting of cosmic dust. This gives grounds to assert that such an extraterrestrial substance affects some of the processes occurring on planet Earth.

Influence of cosmic dust on the upper atmosphere

Recent studies suggest that the amount of cosmic dust can affect the change in the upper atmosphere. This process is very significant, because it leads to certain fluctuations in the climatic characteristics of planet Earth.

A huge amount of dust from the collision of asteroids fills the space around our planet. Its amount reaches almost 200 tons per day, which, according to scientists, cannot but leave its consequences.

Most susceptible to this attack, according to the same experts, the northern hemisphere, whose climate is predisposed to cold temperatures and dampness.

The impact of cosmic dust on cloud formation and climate change is not well understood. New research in this area gives rise to more and more questions, the answers to which have not yet been received.

Influence of dust from space on the transformation of oceanic silt

Irradiation of cosmic dust by the solar wind leads to the fact that these particles fall to the Earth. Statistics show that the lightest of the three isotopes of helium in large quantities falls through dust particles from space into oceanic silt.

The absorption of elements from space by minerals of ferromanganese origin served as the basis for the formation of unique ore formations on the ocean floor.

At the moment, the amount of manganese in areas that are close to the Arctic Circle is limited. All this is due to the fact that cosmic dust does not enter the World Ocean in those areas due to ice sheets.

Influence of cosmic dust on the composition of the ocean water

If we consider the glaciers of Antarctica, they amaze with the number of meteorite remains found in them and the presence of cosmic dust, which is a hundred times higher than the usual background.

An excessively high concentration of the same helium-3, valuable metals in the form of cobalt, platinum and nickel, makes it possible to assert with certainty the fact of the intervention of cosmic dust in the composition of the ice sheet. At the same time, the substance of extraterrestrial origin remains in its original form and not diluted by the waters of the ocean, which in itself is a unique phenomenon.

According to some scientists, the amount of cosmic dust in such peculiar ice sheets over the past million years is on the order of several hundred trillion formations of meteorite origin. During the period of warming, these covers melt and carry elements of cosmic dust into the World Ocean.

Watch a video about space dust:

This cosmic neoplasm and its influence on some factors of the life of our planet have not yet been studied enough. It is important to remember that a substance can affect climate change, the structure of the ocean floor and the concentration of certain substances in the waters of the oceans. Photos of cosmic dust testify to how many more mysteries these microparticles hide in themselves. All this makes the study of this interesting and relevant!

Interstellar dust is a product of various intensity processes occurring in all corners of the Universe, and its invisible particles even reach the surface of the Earth, flying in the atmosphere around us.

A repeatedly confirmed fact - nature does not like emptiness. Interstellar outer space, which seems to us to be vacuum, is actually filled with gas and microscopic dust particles, 0.01-0.2 microns in size. The combination of these invisible elements gives rise to objects of enormous size, a kind of clouds of the Universe, capable of absorbing some types of spectral radiation from stars, sometimes completely hiding them from earthly researchers.

What is interstellar dust made of?

These microscopic particles have a nucleus, which is formed in the gaseous envelope of stars and depends entirely on its composition. For example, graphite dust is formed from grains of carbon luminaries, and silicate dust is formed from oxygen ones. This is an interesting process that lasts for decades: when the stars cool down, they lose their molecules, which, flying into space, combine into groups and become the basis of the core of a dust grain. Further, a shell of hydrogen atoms and more complex molecules is formed. At low temperatures, interstellar dust is in the form of ice crystals. Wandering around the Galaxy, little travelers lose part of the gas when heated, but new molecules take the place of the departed molecules.

Location and properties

The main part of the dust that falls on our Galaxy is concentrated in the region of the Milky Way. It stands out against the background of stars in the form of black stripes and spots. Despite the fact that the weight of dust is negligible compared to the weight of gas and is only 1%, it is able to hide celestial bodies from us. Although the particles are separated from each other by tens of meters, but even in this amount, the densest regions absorb up to 95% of the light emitted by stars. The sizes of gas and dust clouds in our system are really huge, they are measured in hundreds of light years.

Impact on observations

Thackeray globules obscure the region of the sky behind them

Interstellar dust absorbs most of the radiation from stars, especially in the blue spectrum, it distorts their light and polarity. Short waves from distant sources receive the greatest distortion. Microparticles mixed with gas are visible as dark spots on the Milky Way.

In connection with this factor, the core of our Galaxy is completely hidden and is available for observation only in infrared rays. Clouds with a high concentration of dust become almost opaque, so the particles inside do not lose their icy shell. Modern researchers and scientists believe that it is they who stick together to form the nuclei of new comets.

Science has proven the influence of dust granules on the processes of star formation. These particles contain various substances, including metals, which act as catalysts for numerous chemical processes.

Our planet increases its mass every year due to falling interstellar dust. Of course, these microscopic particles are invisible, and in order to find and study them, they explore the ocean floor and meteorites. The collection and delivery of interstellar dust has become one of the functions of spacecraft and missions.

When entering the Earth's atmosphere, large particles lose their shell, and small particles invisibly circle around us for years. Cosmic dust is ubiquitous and similar in all galaxies, astronomers regularly observe dark lines on the face of distant worlds.