Cosmic dust. Collection of KSE documents on the study of the Tunguska meteorite
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.
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 impact areas.
- Spherules of metallic formation. This subspecies has a core of cobalt and nickel, as well as a shell that has oxidized.
- Balls of uniform 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 substance 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!
Scientists at the University of Hawaii made a sensational discovery - cosmic dust contains organic matter, including water, which confirms the possibility of transferring various forms of life from one galaxy to another. Comets and asteroids traveling through space regularly bring masses of stardust into the atmosphere of planets. Thus, interstellar dust acts as a kind of “transport” that can deliver water and organic matter to Earth and to other planets of the solar system. Perhaps, once upon a time, a stream of cosmic dust led to the emergence of life on Earth. It is possible that life on Mars, the existence of which causes much controversy in scientific circles, could have arisen in the same way.
The mechanism of water formation in the structure of cosmic dust
As they move through space, the surface of interstellar dust particles is irradiated, which leads to the formation of water compounds. This mechanism can be described in more detail as follows: hydrogen ions present in solar vortex flows bombard the shell of cosmic dust grains, knocking out individual atoms from the crystalline structure of a silicate mineral - the main building material of intergalactic objects. As a result of this process, oxygen is released, which reacts with hydrogen. Thus, water molecules containing inclusions of organic substances are formed.
Colliding with the surface of the planet, asteroids, meteorites and comets bring a mixture of water and organic matter to its surface
What cosmic dust- a companion of asteroids, meteorites and comets, carries molecules of organic carbon compounds, it was known before. But it has not been proven that stardust also transports water. Only now have American scientists discovered for the first time that organic matter transported by interstellar dust particles together with water molecules.
How did water get to the Moon?
The discovery of scientists from the United States may help lift the veil of mystery over the mechanism of formation of strange ice formations. Despite the fact that the surface of the Moon is completely dehydrated, an OH compound was discovered on its shadow side using sounding. This find indicates the possible presence of water in the depths of the Moon.
The far side of the Moon is completely covered with ice. Perhaps it was with cosmic dust that water molecules reached its surface many billions of years ago
Since the era of the Apollo rovers in lunar exploration, when lunar soil samples were brought to Earth, scientists have come to the conclusion that sunny wind causes changes in the chemical composition of stardust covering the surfaces of planets. There was still debate about the possibility of the formation of water molecules in the thickness of cosmic dust on the Moon, but the analytical research methods available at that time were unable to either prove or disprove this hypothesis.
Cosmic dust is a carrier of life forms
Due to the fact that water is formed in a very small volume and is localized in a thin shell on the surface cosmic dust, only now it has become possible to see it using a high-resolution electron microscope. Scientists believe that a similar mechanism for the movement of water with molecules of organic compounds is possible in other galaxies where it revolves around the “parent” star. In their further research, scientists expect to identify in more detail which inorganic and organic matter carbon-based are present in the structure of stardust.
Interesting to know! An exoplanet is a planet that is located outside the solar system and orbits a star. At the moment, about 1000 exoplanets have been visually discovered in our galaxy, forming about 800 planetary systems. However, indirect detection methods indicate the existence of 100 billion exoplanets, of which 5-10 billion have parameters similar to the Earth, that is, they are. A significant contribution to the mission of searching for planetary groups similar to the Solar System was made by the Kepler astronomical telescope satellite, launched into space in 2009, together with the Planet Hunters program.
How could life originate on Earth?
It is very likely that comets traveling through space at high speeds are capable of creating enough energy when colliding with a planet to begin the synthesis of more complex organic compounds, including amino acid molecules, from ice components. A similar effect occurs when a meteorite collides with the icy surface of a planet. The shock wave creates heat, which triggers the formation of amino acids from individual molecules of cosmic dust processed by the solar wind.
Interesting to know! Comets are composed of large blocks of ice formed by the condensation of water vapor during the early creation of the solar system, approximately 4.5 billion years ago. In their structure, comets contain carbon dioxide, water, ammonia, and methanol. These substances, during the collision of comets with the Earth, at an early stage of its development, could produce a sufficient amount of energy for the production of amino acids - building proteins necessary for the development of life.
Computer modeling has demonstrated that icy comets that crashed onto the Earth's surface billions of years ago may have contained prebiotic mixtures and simple amino acids such as glycine, from which life on Earth subsequently originated.
The amount of energy released during the collision of a celestial body and a planet is sufficient to trigger the formation of amino acids
Scientists have discovered that icy bodies with identical organic compounds found in comets can be found inside the solar system. For example, Enceladus, one of the satellites of Saturn, or Europa, a satellite of Jupiter, contain in their shell organic matter, mixed with ice. Hypothetically, any bombardment of satellites by meteorites, asteroids or comets could lead to the emergence of life on these planets.
In contact with
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 bright star near the dust nebula, 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 densities 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 huge, dark clouds of interstellar gas are composed mainly of hydrogen, which, even at low temperatures, emits radio waves at a length of 21 cm. These radio waves travel unimpeded 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 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. 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, it is of great importance to study the properties of cosmic dust and determine 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, either entering into chemical reactions with the dust grain atoms (chemisorption) or completing the formation of the emerging 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. In this lecture we will talk to you about dust. But not about the kind that accumulates in your rooms, but about cosmic dust. What is it?
Cosmic dust is very small particles of solid matter found anywhere in the Universe, including meteorite dust and interstellar matter that can absorb starlight and form dark nebulae in galaxies. Spherical dust particles about 0.05 mm in diameter are found in some marine sediments; It is believed that these are the remnants of the 5,000 tons of cosmic dust that fall on the globe every year.
Scientists believe that cosmic dust is formed not only from collisions and destruction of small solid bodies, but also due to the condensation of interstellar gas. Cosmic dust is distinguished by its origin: dust can be intergalactic, interstellar, interplanetary and circumplanetary (usually in a ring system).
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 include planetary and protostellar nebulae, stellar atmospheres, and interstellar clouds.
Entire clouds of cosmic dust, which are located in the layer of stars that form the Milky Way, prevent us from observing distant star clusters. A star cluster like the Pleiades is completely immersed in a dust cloud. The brightest stars in this cluster illuminate the dust like a lantern illuminates fog at night. Cosmic dust can only shine by reflected light.
Blue rays of light passing through cosmic dust are attenuated more than red rays, so the starlight that reaches us appears yellowish or even reddish. Entire regions of world space remain closed to observation precisely because of cosmic dust.
Interplanetary dust, at least in comparative proximity to the Earth, is fairly studied matter. Filling the entire space of the Solar System and concentrated in the plane of its equator, it was born largely as a result of random collisions of asteroids and the destruction of comets approaching the Sun. The composition of the dust, in fact, does not differ from the composition of meteorites falling on the Earth: it is very interesting to study it, and there are still many discoveries to be made in this area, but there seems to be no particular intrigue here. But thanks to this particular dust, in good weather in the west immediately after sunset or in the east before sunrise, you can admire a pale cone of light above the horizon. This is the so-called zodiacal light - sunlight scattered by small cosmic dust particles.
Interstellar dust is much more interesting. Its distinctive feature is the presence of a solid core and shell. The core appears to be composed mainly of carbon, silicon and metals. And the shell is mainly made of gaseous elements frozen onto the surface of the core, crystallized under the conditions of “deep freezing” of interstellar space, and this is about 10 kelvins, hydrogen and oxygen. However, there are impurities of molecules in it that are more complex. These are ammonia, methane and even polyatomic organic molecules that stick to a speck of dust or form on its surface during wanderings. Some of these substances, of course, fly away from its surface, for example, under the influence of ultraviolet radiation, but this process is reversible - some fly away, others freeze or are synthesized.
If a galaxy has formed, then where the dust comes from in it is, in principle, clear to scientists. Its most significant sources are novae and supernovae, which lose part of their mass, “dropping” the shell into the surrounding space. In addition, dust is also born in the expanding atmosphere of red giants, from where it is literally swept away by radiation pressure. In their cool, by the standards of stars, atmosphere (about 2.5 - 3 thousand kelvins) there are quite a lot of relatively complex molecules.
But here is a mystery that has not yet been solved. It has always been believed that dust is a product of the evolution of stars. In other words, stars must be born, exist for some time, grow old and, say, produce dust in the last supernova explosion. But what came first - the egg or the chicken? The first dust necessary for the birth of a star, or the first star, which for some reason was born without the help of dust, grew old, exploded, forming the very first dust.
What happened in the beginning? After all, when the Big Bang occurred 14 billion years ago, there were only hydrogen and helium in the Universe, no other elements! It was then that the first galaxies began to emerge from them, huge clouds, and in them the first stars, which had to go through a long life path. Thermonuclear reactions in the cores of stars should have “cooked” more complex chemical elements, turning hydrogen and helium into carbon, nitrogen, oxygen, and so on, and after that the star should have thrown it all into space, exploding or gradually shedding its shell. This mass then needed to cool, cool, and finally turn into dust. But already 2 billion years after the Big Bang, in the earliest galaxies, there was dust! Using telescopes, it was discovered in galaxies 12 billion light years away from ours. At the same time, 2 billion years is too short a period for the full life cycle of a star: during this time, most stars do not have time to grow old. Where the dust came from in the young Galaxy, if there should be nothing there except hydrogen and helium, is a mystery.
Looking at the time, the professor smiled slightly.
But you will try to solve this mystery at home. Let's write down the task.
Homework.
1. Try to guess what came first, the first star or the dust?
Additional task.
1. Report on any type of dust (interstellar, interplanetary, circumplanetary, intergalactic)
2. Essay. Imagine yourself as a scientist tasked with studying cosmic dust.
3. Pictures.
Homemade assignment for students:
1. Why is dust needed in space?
Additional task.
1. Report on any type of dust. Former students of the school remember the rules.
2. Essay. Disappearance of cosmic dust.
3. Pictures.
