Cosmic dust, its composition and properties are little known to people not involved in the study of extraterrestrial space. However, such a phenomenon leaves its traces on our planet! Let's take a closer look at where it comes from and how it affects life on Earth.
Cosmic dust concept
Space dust on Earth is most often found in certain layers of the ocean floor, ice sheets of the planet's polar regions, peat deposits, hard-to-reach desert areas 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. The most convenient option for studying such a phenomenon is considered to be the study of dust from space on the borders of the 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.
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.
Let's consider seven groups of cosmic dust in the atmosphere, different in external indicators:
- 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.
- 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.
- The grains are round in shape, with parameters similar to black sand. Outwardly, they resemble magnetite powder (magnetic iron ore).
- Small black circles with a characteristic shine. Their diameter does not exceed 20 nm, which makes studying them a painstaking task.
- 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.
- 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.
- Balls of heterogeneous structure made of glass and metal. Such elements are characterized by microscopic sizes within 20 nm.
- 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 the ring system of a 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.
- 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.
- Silicate-based group. The base is transparent glass with a specific gravity of approximately three grams per cubic centimeter.
- 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.
- 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 a 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:
- 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.
- The MRN model, the composition of which is determined by the presence of silicate and graphite inclusions.
- Oxide cosmic dust, which is based on diatomic oxides of magnesium, iron, calcium and silicon.
- 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.
The soils are fertile for the presence of cosmic material. A particularly large number of spherules were found 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 provides great opportunities for 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 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 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 amounts to about 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 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!
In interstellar and interplanetary space there are small particles of solid bodies - what we call dust in everyday life. We call the accumulation of these particles cosmic dust to distinguish it from dust in the terrestrial sense, although their physical structure is similar. These are particles ranging in size from 0.000001 centimeter to 0.001 centimeter, the chemical composition of which is generally still unknown.
These particles often form clouds, which are detected in different ways. For example, in our planetary system, the presence of cosmic dust was discovered due to the fact that sunlight scattering on it causes a phenomenon that has long been known as “zodiacal light.” We observe the zodiacal light on exceptionally clear nights in the form of a faintly luminous strip stretching in the sky along the Zodiac; it gradually weakens as we move away from the Sun (which is at this time below the horizon). Measurements of the intensity of zodiacal light and studies of its spectrum show that it comes from the scattering of sunlight on particles forming a cloud of cosmic dust surrounding the Sun and reaching the orbit of Mars (the Earth is thus located inside the cloud of cosmic dust).
The presence of clouds of cosmic dust in interstellar space is detected in the same way.
If any cloud of dust finds itself close to a relatively bright star, then the light from this star will be scattered on the cloud. We then detect this cloud of dust in the form of a bright speck called an “irregular nebula” (diffuse nebula).
Sometimes a cloud of cosmic dust becomes visible because it obscures the stars behind it. Then we distinguish it as a relatively dark spot against the background of a celestial space dotted with stars.
The third way to detect cosmic dust is by changing the color of stars. Stars that lie behind a cloud of cosmic dust are generally more intensely red. Cosmic dust, just like terrestrial dust, causes “reddening” of the light that passes through it. We can often observe this phenomenon on Earth. On foggy nights, we see that the lanterns located far away from us are more red in color than the nearby lanterns, the light of which remains practically unchanged. We must, however, make a reservation: only dust consisting of small particles causes discoloration. And it is precisely this kind of dust that is most often found in interstellar and interplanetary spaces. And from the fact that this dust causes a “reddening” of the light of the stars lying behind it, we conclude that the size of its particles is small, about 0.00001 cm.
We don't know exactly where cosmic dust comes from. Most likely, it arises from those gases that are constantly ejected by stars, especially young ones. Gas freezes at low temperatures and turns into a solid - into particles of cosmic dust. And, conversely, part of this dust, finding itself in a relatively high temperature, for example, near some hot star, or during the collision of two clouds of cosmic dust, which, generally speaking, is a common phenomenon in our region of the Universe, turns back into gas.
There are billions of stars and planets in the universe. And while a star is a glowing sphere of gas, planets like Earth are made up of solid elements. Planets form in clouds of dust that swirl around a newly formed star. In turn, the grains of this dust are composed of elements such as carbon, silicon, oxygen, iron and magnesium. But where do cosmic dust particles come from? A new study from the Niels Bohr Institute in Copenhagen shows that dust grains can not only form in giant supernova explosions, they can also survive the subsequent shock waves of various explosions that impact the dust.
A computer image of how cosmic dust is formed during supernova explosions. Source: ESO/M. Kornmesser
How cosmic dust was formed has long been a mystery to astronomers. The dust elements themselves form in flaming hydrogen gas in stars. Hydrogen atoms combine with each other to form increasingly heavier elements. As a result, the star begins to emit radiation in the form of light. When all the hydrogen is exhausted and it is no longer possible to extract energy, the star dies, and its shell flies into outer space, which forms various nebulae in which young stars can again be born. Heavy elements are formed primarily in supernovae, the progenitors of which are massive stars that die in a giant explosion. But how single elements clump together to form cosmic dust remained a mystery.
“The problem was that even if dust were formed along with elements in supernova explosions, the event itself is so violent that these small grains simply should not survive. But cosmic dust exists, and its particles can be of completely different sizes. Our research sheds light on this problem,” Professor Jens Hjort, head of the Center for Dark Cosmology at the Niels Bohr Institute.
A Hubble telescope image of the unusual dwarf galaxy that produced the bright supernova SN 2010jl. The image was taken before its appearance, so the arrow shows its progenitor star. The star that exploded was very massive, approximately 40 solar masses. Source: ESO
In cosmic dust studies, scientists are observing supernovae using the X-shooter astronomical instrument at the Very Large Telescope (VLT) facility in Chile. It has amazing sensitivity, and the three spectrographs included in it. can observe the entire range of light at once, from ultraviolet and visible to infrared. Hjorth explains that they initially expected a “proper” supernova explosion to occur. And so, when this happened, a campaign to monitor it began. The observed star was unusually bright, 10 times brighter than the average supernova, and its mass was 40 times that of the Sun. In total, observing the star took the researchers two and a half years.
“Dust absorbs light, and using our data we were able to calculate a function that could tell us about the amount of dust, its composition and grain size. We found something truly exciting in the results,” Krista Gaul.
The first step toward the formation of cosmic dust is a mini-explosion in which a star ejects material containing hydrogen, helium and carbon into space. This gas cloud becomes a kind of shell around the star. A few more such flashes and the shell becomes denser. Finally, the star explodes and a dense gas cloud completely envelops its core.
“When a star explodes, the shock wave hits the dense gas cloud like a brick hitting a concrete wall. All this happens in the gas phase at incredible temperatures. But the place where the explosion hit becomes dense and cools down to 2000 degrees Celsius. At this temperature and density, the elements can nucleate and form solid particles. We found dust grains as small as one micron, which is very large for these elements. With such dimensions, they will be able to survive their future journey through the galaxy.”
Thus, scientists believe that they have found the answer to the question of how cosmic dust is formed and lives.
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. The radiation absorbed by the dust particle 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, is directly studied as part of meteorites that fell on the Earth’s surface, in the upper layers of the Earth’s atmosphere (interplanetary dust and the remains of small comets), during spacecraft flights to planets, asteroids and comets (circumstellar and cometary dust) and beyond. limits of the heliosphere (interstellar dust). Ground-based and space-based remote observations of cosmic dust cover the 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 classes 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.
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 of 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- meteoric 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. According to modern concepts, 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 of cosmic dust settle 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, f pranc. 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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