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

It has been proven many times that nature does not like emptiness. Interstellar outer space, which appears to us as a vacuum, is actually filled with gas and microscopic, 0.01-0.2 microns in size, dust particles. The combination of these invisible elements gives rise to objects of enormous size, a kind of clouds of the Universe, capable of absorbing certain types of spectral radiation from stars, sometimes completely hiding them from earthly researchers.

What is interstellar dust made of?

These microscopic particles have a core that is formed in the gas envelope of stars and is completely dependent on its composition. For example, graphite dust is formed from grains of carbon stars, and silicate dust is formed from oxygen particles. This is an interesting process that lasts for decades: as stars cool, they lose their molecules, which, flying into space, join into groups and become the basis of the core of a dust grain. Next, a shell of hydrogen atoms and more complex molecules is formed. In conditions low temperatures Interstellar dust is found in the form of ice crystals. Wandering around the Galaxy, little travelers lose some of the gas when heated, but new molecules take the place of the departed molecules.

Location and properties

The bulk of the dust that falls on our Galaxy is concentrated in the region 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 capable of hiding celestial bodies from us. Although the particles are separated from each other by tens of meters, even in this quantity the densest regions absorb up to 95% of the light emitted by the stars. The size of the gas and dust clouds in our system is truly enormous, measured in hundreds of light years.

Impact on observations

Thackeray's globules make the area of ​​the sky behind them invisible

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

Due to this factor, the core of our Galaxy is completely hidden and accessible to 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, when sticking together, that 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 the falling stardust. Of course, these microscopic particles are invisible, and to find and study them, they study the ocean floor and meteorites. The collection and delivery of interstellar dust has become one of the functions of spacecraft and missions.

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

Cosmic dust

particles of matter in interstellar and interplanetary space. Light-absorbing condensations of cosmos 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 the visible region, extinction is approximately proportional to 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 (the elongated shape of dielectric particles or the anisotropy of the conductivity of graphite) 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.

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

See what “Cosmic dust” is in other dictionaries:

Particles of condensed matter in interstellar and interplanetary space. According to modern concepts, cosmic dust consists of particles measuring approx. 1 µm with a graphite or silicate core. In the Galaxy, cosmic dust forms... ... Big Encyclopedic Dictionary

COSMIC DUST, very small particles of solid matter found in any part of the Universe, including meteorite dust and interstellar matter, capable of absorbing starlight and forming dark nebulae in galaxies. Spherical... ... Scientific and technical encyclopedic dictionary

COSMIC DUST - meteor dust, as well as the smallest particles of matter that form dust and other nebulae in interstellar space... Big Polytechnic Encyclopedia

cosmic dust- Very small particles of solid matter present in outer space and falling to the Earth... Dictionary of Geography

Particles of condensed matter in interstellar and interplanetary space. By modern ideas, cosmic dust consists of particles about 1 micron in size with a core of graphite or silicate. In the Galaxy, cosmic dust forms... ... Encyclopedic Dictionary

It is formed in space by particles ranging in size from several molecules to 0.1 mm. 40 kilotons cosmic dust settles on planet Earth every year. Cosmic dust can also be distinguished by its astronomical position, for example: intergalactic dust, ... ... Wikipedia

cosmic dust- kosminės dulkės statusas T sritis fizika atitikmenys: engl. cosmic dust; interstellar dust; space dust vok. interstellarer Staub, m; kosmische Staubteilchen, m rus. cosmic dust, f; interstellar dust, fpranc. poussière cosmique, f; poussière… … Fizikos terminų žodynas

cosmic dust- kosminės dulkės statusas T sritis ekologija ir aplinkotyra apibrėžtis Atmosferoje susidarančios meteorinės dulkės. atitikmenys: engl. cosmic dust vok. kosmischer Staub, m rus. cosmic dust, f... Ekologijos terminų aiškinamasis žodynas

Particles condensed into va in interstellar and interplanetary space. According to modern According to the ideas, K. p. consists of particles measuring approx. 1 µm with a graphite or silicate core. In the Galaxy, the cosmos forms condensations of clouds and globules. Calls... ... Natural science. Encyclopedic Dictionary

Particles of condensed matter in interstellar and interplanetary space. Consists of particles about 1 micron in size with a core of graphite or silicate, in the Galaxy it forms clouds that cause a weakening of the light emitted by stars and... ... Astronomical Dictionary

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

In addition to the Tunguska meteorite, a number of craters of meteorite origin are also known. 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.

In addition to 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.

Supernova SN2010jl Photo: NASA/STScI

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

We are all made of stardust, of the elements that are 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 active activity is taking place has remained a mystery until now.

This question was first clarified by observations made using the Very Large Telescope at the Paranal Observatory in northern Chile. An international research team led by Christa Gall from the Danish University of Aarhus examined a supernova that occurred in 2010 in a galaxy 160 million light years away. Researchers spent months and early years observing catalog number SN2010jl in visible and infrared light 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.” This made it possible to study in more detail the different sizes of dust grains and their formation.

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

As it turns out, dust particles larger than a thousandth of a millimeter form in the dense material around the star relatively quickly. The sizes of these particles are surprisingly large for cosmic dust grains, making them resistant to destruction by galactic processes. “Our evidence of the formation of large dust particles shortly after the supernova explosion means that there must be a rapid and effective way their formation," adds co-author Jens Hjorth from 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, dust formation occurs in 2 stages:

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

"IN lately Astronomers have discovered a lot of dust in the remnants of supernovae that arose after the explosion. However, they also found evidence of a small amount of dust that actually originated from the supernova itself. New observations explain how this apparent contradiction may be resolved,” writes Christa Gall in conclusion.

COSMIC DUST, solid particles with characteristic sizes from about 0.001 microns to about 1 microns (and possibly up to 100 microns or more in the interplanetary medium and protoplanetary disks), found in almost all astronomical objects: from the Solar System to very distant galaxies and quasars . Dust characteristics (particle concentration, chemical composition, particle size, etc.) vary significantly from one object to another, even for objects of the same type. Cosmic dust scatters and absorbs incident radiation. Scattered radiation with the same wavelength as the incident radiation propagates in all directions. Radiation absorbed by a speck of dust is transformed into thermal energy, and the particle usually emits in a longer wavelength region of the spectrum compared to the incident radiation. Both processes contribute to extinction - the weakening of the radiation of celestial bodies by dust located on the line of sight between the object and the observer.

Dust objects are studied in almost the entire range of electromagnetic waves - from X-rays to millimeter waves. Electrical dipole radiation from rapidly rotating ultrafine particles appears to make some contribution to microwave emission at frequencies of 10-60 GHz. An important role is played by laboratory experiments in which they measure refractive indices, as well as absorption spectra and scattering matrices of particles - analogues of cosmic dust grains, simulate the processes of formation and growth of refractory dust grains in the atmospheres of stars and protoplanetary disks, study the formation of molecules and the evolution of volatile dust components in conditions similar to those existing in dark interstellar clouds.

Cosmic dust located in various physical conditions, are directly studied in the composition of meteorites that fell on the Earth’s surface, in upper layers earth's atmosphere(interplanetary dust and remnants of small comets), during spacecraft flights to planets, asteroids and comets (circumplanetary and cometary dust) and beyond the heliosphere (interstellar dust). Ground-based and space-based remote observations of cosmic dust cover solar system(interplanetary, circumplanetary and cometary dust, dust near the Sun), the interstellar medium of our Galaxy (interstellar, circumstellar and nebular dust) and other galaxies (extragalactic dust), as well as very distant objects (cosmological dust).

Cosmic dust particles mainly consist of carbonaceous substances (amorphous carbon, graphite) and magnesium-iron silicates (olivines, pyroxenes). They condense and grow in the atmospheres of stars of late spectral types and in protoplanetary nebulae, and are then ejected into the interstellar medium by radiation pressure. In interstellar clouds, especially dense ones, refractory particles continue to grow as a result of the accretion of gas atoms, as well as when particles collide and stick together (coagulation). This leads to the appearance of shells of volatile substances (mainly ice) and to the formation of porous aggregate particles. The destruction of dust grains occurs as a result of sputtering in shock waves arising after supernova explosions, or evaporation during the process of star formation that began in the cloud. The remaining dust continues to evolve near the formed star and later manifests itself in the form of an interplanetary dust cloud or cometary nuclei. Paradoxically, around evolved (old) stars the dust is “fresh” (recently formed in their atmosphere), and around young stars the dust is old (evolved as part of the interstellar medium). It is believed that cosmological dust, possibly existing in distant galaxies, was condensed in the ejections of material from the explosions of massive supernovae.

Lit. look at Art. Interstellar dust.