Where does cosmic dust come from? Our planet is surrounded by a dense air shell - the atmosphere. The composition of the atmosphere, in addition to the gases known to everyone, also includes solid particles - dust.

It mainly consists of soil particles that rise upward under the influence of the wind. During volcanic eruptions, powerful dust clouds are often observed. Entire “dust caps” hang over large cities, reaching a height of 2-3 km. The number of dust particles in one cubic meter. cm of air in cities reaches 100 thousand pieces, while in clean mountain air there are only a few hundred of them. However, dust of terrestrial origin rises to relatively low altitudes - up to 10 km. Volcanic dust can reach a height of 40-50 km.

Origin of cosmic dust

The presence of dust clouds has been established at altitudes significantly exceeding 100 km. These are the so-called “noctilucent clouds”, consisting of cosmic dust.

The origin of cosmic dust is extremely diverse: it includes the remains of disintegrated comets and particles of matter ejected by the Sun and brought to us by the force of light pressure.

Naturally, under the influence of gravity, a significant part of these cosmic dust particles slowly settles to the ground. The presence of such cosmic dust was discovered on high snowy peaks.

Meteorites

In addition to this slowly settling cosmic dust, hundreds of millions of meteors burst into our atmosphere every day - what we call “falling stars”. Flying with escape velocity at hundreds of kilometers per second, they burn out from friction with air particles before they reach the surface of the earth. The products of their combustion also settle on the ground.

However, among the meteors there are also exceptionally large specimens that reach the surface of the earth. Thus, the fall of the large Tunguska meteorite at 5 o’clock in the morning on June 30, 1908 is known, accompanied by a number of seismic phenomena noted even in Washington (9 thousand km from the place of fall) and indicating the power of the explosion when the meteorite fell. Professor Kulik, who with exceptional courage examined the site of the meteorite fall, found a thicket of windfall surrounding the site of the fall within a radius of hundreds of kilometers. Unfortunately, he was unable to find the meteorite. An employee of the British Museum, Kirkpatrick, made a special trip to the USSR in 1932, but did not even get to the site of the meteorite fall. However, he confirmed the assumption of Professor Kulik, who estimated the mass fallen meteorite 100-120 tons.

Cloud of cosmic dust

An interesting hypothesis is that of Academician V.I. Vernadsky, who considered it possible that it was not a meteorite that would fall, but a huge cloud of cosmic dust moving at colossal speed.

Academician Vernadsky confirmed his hypothesis by the appearance these days of a large number of luminous clouds moving towards high altitude at a speed of 300-350 km per hour. This hypothesis could also explain the fact that the trees surrounding the meteorite crater remained standing, while those located further were knocked down by the blast wave.

In addition to the Tunguska meteorite, it is also known whole line craters of meteorite origin. The first of these craters to be surveyed can be called the Arizona crater in Devil's Canyon. It is interesting that not only fragments of an iron meteorite were found near it, but also small diamonds formed from carbon from high temperature and pressure during the fall and explosion of the meteorite.
In addition to the indicated craters, indicating the fall of huge meteorites weighing tens of tons, there are also smaller craters: in Australia, on the island of Ezel and a number of others.

Besides large meteorites, quite a lot of smaller ones fall out every year - weighing from 10-12 grams to 2-3 kilograms.

If the Earth were not protected by a thick atmosphere, we would be bombarded every second by tiny cosmic particles traveling at speeds faster than bullets.

Cosmic X-ray background

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

Rupture of the Universe

Dust circumplanetary complexes: fig4

Properties of cosmic dust

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

Introduction

Many people admire with delight the beautiful spectacle of the starry sky, one of nature's greatest creations. In the clear autumn sky, it is clearly visible how a faintly luminous strip, called the Milky Way, runs across the entire sky, having irregular outlines with different widths and brightness. If we examine the Milky Way, which forms our Galaxy, through a telescope, it will turn out that this bright strip breaks up into many faintly luminous stars, which for the naked eye merge into a continuous glow. 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 of luminous rarefied gases got the name gaseous diffuse nebulae. One of the most famous is the nebula in Orion constellation, 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 cold light, re-emitting the light of neighboring hot stars. The composition of gaseous diffuse nebulae consists mainly 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.

IN interstellar space Diffuse dust nebulae are also observed. These clouds are made up of tiny solid grains of dust. If there is a dust nebula near bright Star, then its light is scattered by this nebula and the dust nebula becomes directly observable(Fig. 1). Gas and dust nebulae can generally absorb the light of the stars behind them, so in sky photographs they are often visible as black, gaping holes against the background of the Milky Way. Such nebulae are called dark nebulae. There is one very large dark nebula in the sky of the southern hemisphere, which navigators nicknamed the Coal Sack. There is no clear boundary between gas and dust nebulae, so they are often observed together as gas and dust 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 gas in them. Indeed, over a long distance, even such rarefied gas can absorb the radiation of stars. Emergence and rapid development radio astronomy made it possible to detect this invisible gas by the radio waves it emits. The vast, dark clouds of interstellar gas are composed primarily of hydrogen, which even when 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 study 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, emerging from the center of the Galaxy, wrap around its middle, creating something similar to a cuttlefish with long tentacles caught in a whirlpool.

Currently, a huge amount of matter in our Galaxy is in the form of gas and dust nebulae. Interstellar diffuse matter is concentrated relatively thin layer V equatorial plane our star system. Clouds of interstellar gas and dust block the center of the Galaxy from us. Due to 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 of all optical spectrum of a star Blue rays are absorbed more strongly and photons corresponding to red are absorbed more weakly. This effect leads to the phenomenon of reddening of the light of stars passing through the interstellar medium.

For astrophysicists great value has the study of the properties of cosmic dust and the clarification of the influence that this dust has when studying physical characteristics of astrophysical objects. Interstellar absorption and interstellar polarization of light, infrared radiation of neutral hydrogen regions, deficiency chemical elements in the interstellar medium, issues 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 discussed 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 violent ejections of gas from the cores 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 grains, the gas temperature drops as the gas moves outward and at some point passes through the dew point, at which condensation of vapors of substances, forming the nuclei of dust grains. The centers of formation of a new phase are usually clusters. Clusters are small groups of atoms or molecules that form a stable quasi-molecule. When colliding with an already formed dust grain nucleus, atoms and molecules can join it, or enter into chemical reactions with atoms of a dust grain (chemisorption), or completing the formation of a cluster. In the densest regions of the interstellar medium, the concentration of particles in which is cm -3, the growth of dust grains can be associated with coagulation processes, in which dust grains can stick together without being destroyed. Coagulation processes, depending on the surface properties of dust grains and their temperatures, occur only when collisions between dust grains occur at low relative collision velocities.

In Fig. Figure 2 shows the process of growth of cosmic dust clusters using the addition of monomers. The resulting amorphous cosmic dust particle may be a cluster of atoms with fractal properties. Fractals are called geometric objects: lines, surfaces, spatial bodies that have a highly rugged shape and have the property of self-similarity. Self-similarity means the unchanged basic geometric characteristics fractal object when changing the scale. For example, images of many fractal objects turn out to be very similar when the resolution in a microscope increases. Fractal clusters are highly branched porous structures formed under highly nonequilibrium conditions when solid particles of similar sizes combine into one whole. Under terrestrial conditions, fractal aggregates are obtained when vapor relaxation metals in nonequilibrium conditions, during the formation of gels in solutions, during the coagulation of particles in smoke. The model of a fractal cosmic dust particle is shown in Fig. 3. Note that the processes of coagulation of dust grains occurring in protostellar clouds and gas and dust disks, are significantly enhanced by turbulent motion interstellar matter.

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

Hello!

Today we will talk about very most interesting topic, associated with such a science as astronomy! We're talking about cosmic dust. I assume that many people learned about it for the first time. So, I need to tell you everything that only I know about her! At school, astronomy was one of my favorite subjects, I will say more - my favorite, because it was in astronomy that I took the exam. Although I got the 13th ticket, which was the most difficult, I passed the exam perfectly and was satisfied!

If we can say in a completely understandable way what cosmic dust is, then we can imagine all the fragments that exist in the Universe from cosmic matter, for example, from asteroids. But the Universe is not only Space! Don’t be confused, my dears and good ones! The Universe is our entire world - our entire huge globe!

How is cosmic dust formed?

For example, cosmic dust can be formed when two asteroids collide in space and during the collision, the process of their destruction into small particles occurs. Many scientists are also inclined to believe that its formation is related to when interstellar gas condenses.

How does cosmic dust originate?

We have just found out how it is formed, now we are learning about how it arises. As a rule, these specks of dust simply appear in the atmospheres of red stars; if you have heard, such red stars are also called dwarf stars; arise when various explosions occur on stars; when gas is actively ejected from the galactic nuclei themselves; protostellar and planetary nebula- also contributes to its occurrence, however, like the stellar atmosphere itself and interstellar clouds.

What types of cosmic dust can be distinguished, given its origin?

As for the species specifically, regarding origin, we highlight the following types:

interstellar type of dust, when an explosion occurs on stars, there is a huge release of gas and a powerful release of energy

intergalactic,

interplanetary,

circumplanetary: appeared as “garbage”, remnants, after the formation of other planets.

Are there species that are classified not by origin, but by external characteristics?

black circles, small, shiny

circles are black, but larger in size, with a rough surface

circles balls black and white, which have a silicate base in their composition

circles that consist of glass and metal, they are heterogeneous and small (20 nm)

circles similar to magnetite powder, they are black and look like black sand

ash and slag-like circles

a species that was formed from the collision of asteroids, comets, meteorites

Good question! Of course it can. And from meteorite collisions too. Its formation is possible from the collision of any celestial bodies.

The issue of the formation and occurrence of cosmic dust is still controversial, and different scientists put forward their points of view, but you can adhere to one or two points of view on this issue that are close to you. For example, the one that is more understandable.

After all, even regarding its types there is no absolutely accurate classification!

balls, the base of which is homogeneous; their shell is oxidized;

balls, the base of which is silicate; since they have inclusions of gas, their appearance is often similar to slag or foam;

balls, the base of which is metal with a core of nickel and cobalt; the shell is also oxidized;

circles whose filling is hollow.

they can be icy, and their shell consists of light elements; Large ice particles even contain atoms that have magnetic properties,

circles with silicate and graphite inclusions,

circles consisting of oxides, the basis of which are diatomic oxides:

Cosmic dust not fully studied! There are a lot of open questions, because they are controversial, but I think we still have the basic ideas now!

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 deserts and meteorite craters. The size of this substance is less than 200 nm, which makes its study problematic.

Typically, the concept of cosmic dust includes a distinction between interstellar and interplanetary varieties. However, all this is very conditional. Most convenient option To study such a phenomenon, they consider studying dust from space at the boundaries solar system or beyond.

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

Theories of the origin of cosmic dust

Streams of cosmic dust constantly attack the Earth's surface. The question arises where this substance comes from. Its origins give rise to much debate among experts in the field.

The following theories of the formation of cosmic dust are distinguished:

• Decay of celestial bodies. Some scientists believe that cosmic dust is nothing more than the result of the destruction of asteroids, comets and meteorites.
• Remnants of a protoplanetary type cloud. There is a version according to which cosmic dust is classified as microparticles of a protoplanetary cloud. However, this assumption raises some doubts due to the fragility of the finely dispersed substance.
• The result of an explosion on the stars. As a result of this process, according to some experts, a powerful release of energy and gas occurs, 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 emergence of dust.

According to some studies, a certain part of the cosmic dust component predates the formation of the Solar System, which makes this substance even more interesting for further study. This is worth paying attention to when assessing and analyzing such an extraterrestrial phenomenon.

The main types of cosmic dust

Specific classification of types of cosmic dust on this moment does not exist. Subspecies can be distinguished by visual characteristics and location of these microparticles.

Let's consider seven groups of cosmic dust in the atmosphere, different in external indicators:

1. Gray debris 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 underwent changes after passing through the Earth's atmosphere.
3. Grains round shape, which is similar in parameters to black sand. Outwardly, they resemble magnetite powder (magnetic iron ore).
4. Small black circles with a characteristic shine. Their diameter does not exceed 20 nm, which makes studying them 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. Balls of heterogeneous structure made of glass and metal. Such elements are characterized by microscopic sizes within 20 nm.

According to their astronomical location, there are 5 groups of cosmic dust:

• Dust found in intergalactic space. This type can distort the dimensions of distances during certain calculations and is capable of changing 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 solid consistency.
• Dust located near a certain planet. It is usually located in ring system celestial body.
• Clouds of dust around the stars. They circle along 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 band. Representatives of this subspecies have a specific gravity of more than five grams per cubic centimeter, and their base consists mainly of iron.
2. Silicate-based group. The basis - 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 microparticles in the structure. The base also includes magnetic elements.

Four groups based on the similarity of the internal structure of cosmic dust microparticles:

• Spherules with hollow filling. This species is often found in meteorite crash sites.
• Spherules of metallic formation. This subspecies has a core of cobalt and nickel, as well as a shell that has oxidized.
• Balls of homogeneous build. Such grains have an oxidized shell.
• Balls with silicate base. The presence of gas inclusions gives them the appearance of ordinary slag, and sometimes foam.

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

Composition and characteristics of cosmic dust components

Let's take a closer look at what cosmic dust consists of. There is a certain 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 becomes difficult.

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

1. Ice particles whose structure includes a core with a refractory characteristic. The shell of such a model consists of light elements. Large particles contain atoms with magnetic elements.
2. The MRN model, the composition of which is determined by the presence of silicate and graphite inclusions.
3. Oxide cosmic dust, which is based on diatomic oxides of magnesium, iron, calcium and silicon.

General classification by chemical composition cosmic dust:

• Balls with metallic nature of formation. The composition of such microparticles includes an element such as nickel.
• Metal balls with the presence of iron and the absence of nickel.
• Silicone based circles.
• Iron-nickel balls of irregular shape.

More specifically, we can consider the composition of cosmic dust using the example of those found in ocean silt, sedimentary rocks and glaciers. Their formula will differ little from one another. Findings from the study of the seabed are balls with silicate and metal base with the presence of such chemical elements, like nickel and cobalt. Microparticles containing aluminum, silicon and magnesium were also discovered in the depths of the water element.

The soils are fertile for the presence space material. Especially a large number of spherules were discovered in places where meteorites fell. The basis for them was nickel and iron, as well as various minerals such as troilite, cohenite, steatite and other components.

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

Difficulties in determining the composition of the object under study 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 gives great opportunities in terms of further activities in this direction. At a certain altitude, with the help of rockets, they discovered a specific belt consisting of cosmic dust. This gives grounds to assert that such extraterrestrial matter affects some processes occurring on planet Earth.

The influence of cosmic dust on the upper atmosphere

Recent studies indicate that the amount of cosmic dust can influence changes in upper layers atmosphere. This process very significant because it leads to certain fluctuations in the climatic characteristics of planet Earth.

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

The northern hemisphere, whose climate is prone to cold temperatures and dampness, is most susceptible to this attack, according to the same experts.

The impact of cosmic dust on cloud formation and climate change has not yet been sufficiently studied. New research in this area raises more and more questions, the answers to which have not yet been obtained.

The influence of dust from space on the transformation of oceanic silt

Irradiation of cosmic dust by the solar wind causes these particles to fall to Earth. Statistics show that the lightest of the three isotopes of helium enters ocean silt in huge quantities through dust grains from space.

The absorption of elements from outer 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.

The influence of cosmic dust on the composition of the water of the World Ocean

If we look at the glaciers of Antarctica, they are striking in the number of meteorite remains found in them and the presence of cosmic dust, which is a hundred times higher than the normal background.

The excessively increased concentration of the same helium-3, valuable metals in the form of cobalt, platinum and nickel allows us to confidently assert the fact of the interference 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 ocean waters, which in itself is a unique phenomenon.

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

Watch a video about cosmic dust:

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

Cosmic dust

particles of matter in interstellar and interplanetary space. The light-absorbing condensations of cosmic particles are visible as dark spots in photographs of the Milky Way. Attenuation of light due to the influence of K. p. - so-called. interstellar absorption, or extinction, is not the same for electromagnetic waves different lengths λ , as a result of which reddening of stars is observed. IN visible area extinction is approximately proportional λ -1, in the near ultraviolet region it is almost independent of wavelength, but around 1400 Å there is an additional absorption maximum. Most of the extinction is due to light scattering rather than absorption. This follows from observations of reflection nebulae containing cosmic particles, visible around stars of spectral class B and some other stars bright enough to illuminate the dust. A comparison of the brightness of nebulae and the stars that illuminate them shows that the albedo of dust is high. The observed extinction and albedo lead to the conclusion that the crystal structure consists of dielectric particles with an admixture of metals with a size slightly less than 1 µm. The ultraviolet extinction maximum can be explained by the fact that inside the dust grains there are graphite flakes measuring about 0.05 × 0.05 × 0.01 µm. Due to the diffraction of light by a particle whose dimensions are comparable to the wavelength, light is scattered predominantly forward. Interstellar absorption often leads to polarization of light, which is explained by the anisotropy of the properties of dust grains ( elongated shape in dielectric particles or anisotropy of graphite conductivity) and their ordered orientation in space. The latter is explained by the action of a weak interstellar field, which orients dust grains with their long axis perpendicular to the field line. Thus, by observing the polarized light of distant celestial bodies, one can judge the orientation of the field in interstellar space.

The relative amount of dust is determined from the average absorption of light in the Galactic plane - from 0.5 to several stellar magnitudes per 1 kiloParsec in the visual region of the spectrum. The mass of dust makes up about 1% of the mass of interstellar matter. Dust, like gas, is distributed non-uniformly, forming clouds and denser formations - Globules. In globules, dust acts as a cooling factor, shielding the light of stars and emitting in the infrared the energy received by the dust grain from inelastic collisions with gas atoms. On the surface of the dust, atoms combine into molecules: the dust is a catalyst.

S. B. Pikelner.

Big Soviet encyclopedia. - M.: Soviet Encyclopedia. 1969-1978 .

See what “Cosmic dust” is in other dictionaries:

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