The address of the planet earth in outer space. The address of the earth in the universe

> Quoted1\u003e\u003e Where is the Earth located in the Milky Way?

The place of the Earth and the solar system in the galaxy Milky Way : where the sun and the planet are, parameters, distance from the center and plane, structure from the photo.

For centuries, scientists have believed that the Earth is the center of the entire universe. It is not difficult to think why this happened, because the Earth is in, and we could not look beyond it. Only a century of research and observations helped to understand that all celestial bodies in the system revolve around the main star.

The system itself also revolves around the galactic center. Although then people did not understand this either. I had to spend a certain period of time to guess about the existence of many galaxies and determine their place in ours. What place does Earth occupy in the Milky Way galaxy?

Location of the Earth in the Milky Way

Earth is located in the Milky Way galaxy. We live in a vast and spacious place, spanning 100,000 to 120,000 light years in diameter and roughly 1,000 light years wide. The territory is home to 400 billion stars.

The galaxy received such a scale thanks to an unusual diet - it absorbed and continues to be fed by other small galaxies. For example, there is now a Dwarf Galaxy on the dining table in Big Dogwhose stars join our disk. But when compared with others, ours is average. Even the neighboring one is twice as large.

Structure

The planet resides in a spiral galaxy with a bar. For many years it was thought that there are 4 arms, but recent studies confirm only two: Shield-Centauri and Keel-Sagittarius. They emerged from dense waves orbiting the galaxy. That is, they are grouped stars and gas clouds.

What about a photo of the Milky Way galaxy? All of them are artistic interpretations or real images, but very similar to our galaxies. Of course, we did not come to this right away, since no one could say exactly what it looks like (we are inside it).

Modern instruments make it possible to count up to 400 billion stars, each of which can be located on the planet. 10-15% of the mass goes to "luminous matter", and the rest is the stars. Despite the huge array, only 6000 light-years in the visible spectrum open to us for observation. But here infrared devices come into play, opening up new territories.

Around the galaxy is a huge dark matter halo, covering as much as 90% of the total mass. No one knows yet what it is, but her presence confirms the effect on other objects. It is believed to keep the Milky Way from disintegrating as it rotates.

The location of the solar system in the Milky Way

Earth is 25,000 light-years distant from the galactic center and the same distance from the edge. If we imagine the galaxy as a giant musical plate, then we are located halfway between the central part and the edge. More specifically, we occupy a place in the Orion arm between the two main arms. It spans 3,500 light years in diameter and stretches 10,000 light years.

It can be seen that the galaxy divides the heavens into two hemispheres. This suggests that we are located close to the galactic plane. The Milky Way has a low surface brightness due to the abundance of dust and gas that obscures the disk. This makes it difficult not only to see the central part, but also to look at the other side.

The system spends 250 million years to bypass the entire orbital path - the "space year". Dinosaurs roamed the last pass on Earth. And what will happen next? Maybe people will die out altogether or will they be replaced by a new species?

All in all, we live in a huge and amazing place. New knowledge makes you get used to the fact that the universe is much larger than all the assumptions. Now you know where the Earth is in the Milky Way.

The large-scale structure of the universe resembles a system of veins and filaments separated by voids

The large-scale structure of the Universe is a cosmological term for the structure of the distribution of matter in the Universe at the largest.

An example of the simplest structure in outer space is the satellite planet system. In addition to the two planets closest to the Sun (Mercury and Venus), all the others have their own satellite, and in most cases not even one. If only the Moon accompanies the Earth, then the whole revolves around Jupiter, although some of them are quite small. However, together with their satellites, the planets of the solar system revolve around the sun, forming the so-called planetary system.

As a result of observations, astronomers have revealed that most other stars are also part of planetary systems. At the same time, the stars themselves also often form systems and clusters, which were called stellar. According to available data, the majority of stars are, or with a multiple of the number of stars. In this regard, our Sun is considered atypical, since it does not have a pair

If we consider the near-solar space on a larger scale, then it becomes obvious that all star clusters, together with their planetary systems, form a star island, the so-called.

The history of studying the structure of the Universe

For the first time, the outstanding astronomer William Herschel pondered the idea of \u200b\u200ba large-scale structure of the Universe. It is he who owns such discoveries as the discovery of the planet Uranus and its two satellites, two satellites of Saturn, the discovery of infrared radiation and the idea of \u200b\u200bthe solar system through outer space. Having independently constructed a telescope and carried out observations, he performed volumetric calculations of luminaries of different brightness in certain regions of the sky and came to the conclusion that there are many star islands in outer space.

Later, at the beginning of the twentieth century, the American cosmologist Edwin Hubble was able to prove that some nebulae belong to structures other than the Milky Way. That is, it was reliably known that there are also various star clusters outside our galaxy. Research in this direction soon greatly expanded our understanding of the universe. It turned out that in addition to the Milky Way, there are tens of thousands of other galaxies in outer space. In an attempt to draw up some kind of simplified map of the visible Universe, scientists stumbled upon the remarkable fact that galaxies in space and constitute other structures of unthinkable sizes.

Over time, scientists discovered that lone galaxies are quite rare in the universe. The overwhelming majority of galaxies form large-scale clusters, which can be of various shapes and include two galaxies or a multiple, up to several thousand. In addition to huge stellar islands, these massive stellar structures also include accumulations of gas heated to high temperatures. Despite its very low density (thousands of times less than in the solar atmosphere), the mass of this gas can significantly exceed the total mass of all stars in some sets of galaxies.

The results of observations and calculations led scientists to the idea that galaxy clusters can also form other larger structures. This was followed by two intriguing questions: if the galaxy itself, a complex structure, is part of some larger structure, can this structure be a composite of something even larger? And, in the end, is there a limit to such a hierarchical structure, when each system is part of the other?

A positive answer to the first question is confirmed by the presence of superclusters of galaxies, which in turn outgrow the galactic filaments, or as they are otherwise called "walls". Their thickness is on average about 10 million sv. years, and the length is 160 - 260 million light years. However, answering the second question, it should be noted that superclusters of galaxies are not a kind of isolated structure, but only denser sections of galactic walls. Therefore, today scientists are confident that it is the galactic filaments (walls), the largest cosmic structures, mixed with voids (empty space free from star clusters) that form the fibrous or cellular structure of the Universe.

The position of the earth in the universe

Departing somewhat from the topic, we indicate the position of our planet in such a complex structure:

1. Planetary system: Solar
2. Local interstellar cloud
3. Orion Galactic Arm
4. Galaxy: Milky Way
5. Cluster of galaxies:
6. Supercluster of galaxies: Local supercluster (Virgo)
7. Supercluster of galaxies: Laniakeya
8. Wall: Pisces-Whale Supercluster Complex

Modern research results claim that the universe consists of at least 200 billion galaxies. Galactic walls by their nature are relatively flat and constitute the walls of the "cells" of the Universe, and the places of their intersection form the superclusters of galaxies. In the center of these cells are voids (English void - emptiness).

Analysis of the three-dimensional model of the distribution of galaxies formed by scientists suggests that the cellular structure is observed at a distance of more than a billion light years in any direction. This information allows us to believe that on a scale of several hundred million light years, any fragment of the Universe will have almost the same amount of matter. And this proves that the Universe is homogeneous on the indicated scales.

The causes of the large-scale structure of the Universe

Despite the presence of such large-scale structures as galactic walls and filaments, clusters of galaxies are still considered the largest stable structures. The fact is that the known expansion of the Universe gradually stretches the structure of any objects, and only gravity can fight this force. As a result of observations of clusters and superclusters, such a stunning effect as "" was discovered. That is, the rays passing through interstellar space are bent, which indicates the presence of a huge invisible, hidden mass in it. It can belong to various unobservable cosmic bodies, but on such scales it most likely belongs

Einstein's cross - gravitationally lensed quasar

Based on the almost homogeneous, scientists are convinced that the substance in the Universe should be distributed evenly. But the peculiarity of gravity is that it tends to pull any physical particles into dense structures, thereby violating homogeneity. Thus, some time after the Big Bang, insignificant inhomogeneities in the distribution of matter in space began to contract more and more into some structures. Their increasing gravity (due to the increase in mass per volume) gradually slowed down the expansion until it stopped it altogether. Moreover, in some parts the expansion turned into contraction, which caused the formation of galaxies and galaxy clusters.

A similar model was verified using computer calculations. Taking into account very insignificant fluctuations (fluctuations, deviations) in the homogeneity of the relict radiation, the computer calculated that the same small fluctuations in the after the Big Bang with the help of gravity could well give rise to clusters of galaxies and a cellular large-scale structure of the Universe.

Throughout the history of science, the range of interests of geosciences included the development of ideas about the world around a person - the planet Earth, the solar system, the universe. The first mathematically grounded model of the universe was the geocentric system of K. Ptolemy (165-87 BC), which correctly for that time reflected the part of the world accessible for direct observation. Only after 1500 years, the heliocentric model of the solar system by N. Copernicus (1473-1543) was established.

The successes of physical theory and astronomy at the end of the 19th century. and the appearance of the first optical telescopes led to the creation of ideas about an unchanging universe. The development of the theory of relativity and its application to the solution of cosmological paradoxes (gravitational, photometric) created the relativistic theory of the Universe, which was originally presented by A. Einstein as a static model. In 1922-1924 gt. A.A. Friedman obtained solutions of the equations of the general theory of relativity for matter uniformly filling all space (model of a homogeneous isotropic Universe), which showed that the Universe is unsteady - it must expand or contract. In 1929 E. Hubble discovered the expansion of the Universe, refuting the idea of \u200b\u200bits inviolability. The theoretical results of A.A. Friedman and E. Hubble made it possible to introduce the concept of "beginning" into the evolution of the Universe and explain its structure.

In 1946-1948. G. Gamow developed the theory of the "hot" Universe, according to which at the beginning of evolution the matter of the Universe had a temperature and density that were unattainable experimentally. In 1965, the relic microwave background radiation was discovered, which initially had a very high temperature, which experimentally confirmed the theory of G. Gamow.

This is how our ideas about the world expanded in space and time. If for a long time the Universe was considered as a medium, including celestial bodies of various ranks, then according to modern concepts, the Universe is an ordered system developing unidirectionally. Along with this, the assumption arose that the Universe does not necessarily exhaust the concept of the material world and that other Universes may exist, where the known laws of the universe do not necessarily apply.

Universe

Universe- this is the material world around us, unlimited in time and space. The boundaries of the Universe will most likely move apart as new opportunities for direct observation appear, i.e. they are relative for each point in time.

The universe is one of the concrete scientific objects of experimental research. It is assumed that the fundamental laws of natural science are true for the entire universe.

State of the Universe. The universe is a non-stationary object whose state depends on time. According to the prevailing theory, the Universe is currently expanding: most galaxies (with the exception of those closest to ours) are moving away from us and relative to each other. The speed of removal (recession) is the greater, the further away is the galaxy - the source of radiation. This dependence is described by the Hubble equation:

where v- removal speed, km / s; R- distance to the galaxy, St. year; H -proportionality coefficient, or Hubble constant, Н \u003d 15 × 10 -6 km / (s × sv. year). It has been found that the take-off speed increases.

One of the proofs of the expansion of the Universe is the "redshift of spectral lines" (Doppler effect): spectral absorption lines in objects moving away from the observer always shift towards long (red) spectral waves, and approaching ones - short (blue).

Spectral absorption lines from all galaxies are inherently redshifted, which means that expansion takes place.

The density of the substance of the Universe.The density distribution of matter in certain parts of the Universe differs by more than 30 orders of magnitude. The highest density, if you do not take into account the microcosm (for example, the atomic nucleus), is inherent in neutron stars (about 10 14 g / cm 3), the lowest (10 -24 g / cm 3) - the Galaxy as a whole. According to F.Yu. Siegel, the normal density of interstellar matter in terms of hydrogen atoms is one molecule (2 atoms) in 10 cm 3, in dense clouds - nebulae, it reaches several thousand molecules. If the concentration exceeds 20 hydrogen atoms in 1 cm 3, then the process of approaching begins, which develops into accretion (sticking together).

Substance composition.Of the total mass of matter in the Universe, only about 1/10 is visible (luminous), the remaining 9/10 are invisible (non-luminous) matter. The visible substance, the composition of which can be confidently judged by the nature of the radiation spectrum, is represented mainly by hydrogen (80-70%) and helium (20-30%). There are so few other chemical elements in the luminous mass of matter that they can be neglected. No significant amount of antimatter has been found in the Universe, with the exception of a small fraction of antiprotons in cosmic rays.

The universe is filled with electromagnetic radiation, which is called relict,those. remaining from the early stages of the evolution of the Universe.

Uniformity, isotropy and structure.Globally, the universe is considered isotropicand homogeneous.A sign of isotropy, i.e. the independence of the properties of objects from the direction in space is the uniformity of the distribution of the relic radiation. The most accurate modern measurements did not reveal any deviations in the intensity of this radiation in different directions and depending on the time of day, which simultaneously indicates the great homogeneity of the Universe.

Another feature of the universe is heterogeneityand structure(discreteness) on a small scale. On a global scale of hundreds of megaparsecs, the substance of the Universe can be regarded as a homogeneous continuous medium, the particles of which are galaxies and even clusters of galaxies. A more detailed examination reveals the structuredness of the Universe. The structural elements of the Universe are cosmic bodies, primarily stars, which form stellar systems of various ranks: galaxy- cluster of galaxies- Metagalaxy,They are characterized by localization in space, movement around a common center, a certain morphology and hierarchy.

The Milky Way Galaxy consists of 10 11 stars and an interstellar medium. It belongs to spiral systems that have a plane of symmetry (plane of the disk) and an axis of symmetry (axis of rotation). The flattening of the disk of the Galaxy, observed visually, indicates a significant speed of its rotation around the axis. The absolute linear velocity of its objects is constant and equal to 220-250 km / s (it is possible that it increases for objects very far from the center). The period of rotation of the Sun around the center of the Galaxy is 160-200 million years (on average 180 million years) and is called galactic year.

Evolution of the Universe.In accordance with the model of the expanding Universe, developed by A.A. Friedman on the basis of A. Einstein's general theory of relativity, it is established that:

1) at the beginning of evolution, the Universe experienced a state of cosmological singularity, when the density of its matter was equal to infinity, and the temperature exceeded 10 28 K (at a density above 10 93 g / cm 3, matter has unexplored quantum properties of space-time and gravitation);

2) a substance in a singular state has undergone a sudden expansion, which can be compared to an explosion ("Big Bang");

3) under conditions of nonstationarity of the expanding Universe, the density and temperature of matter decrease in time, i.e. in the process of evolution;

4) at a temperature of about 10 9 K, nucleosynthesis was carried out, as a result of which chemical differentiation of matter took place and the chemical structure of the Universe arose;

5) based on this, the Universe could not exist forever and its age is determined from 13 to 18 billion years.

solar system

Solar system -this is the Sun and a set of celestial bodies: 9 planets and their satellites (in 2002 their number was 100), a lot of asteroids, comets and meteors that revolve around the Sun or enter (like comets) into the Solar system. Basic information about the objects of the solar system contains fig. 3.1 and tab. 3.1.

Table 3.1. Some physical parameters of the planets of the solar system

Solar system object	Distance from the Sun	radius, km	number of terrestrial radii	weight, 10 23 kg	mass relative to Earth	average density, g / cm 3	orbital period, number of earth days	orbital period	number of satellites (moons)	albedo	acceleration of gravity at the equator, m / s 2	speed of separation from the planet's gravity, m / s	availability and composition of the atmosphere, %	average surface temperature, ° С
million km	a.u.
The sun	-		695 400		1,989 × 10 7	332,80	1,41		25-36	9	-		618,0	Is absent
Mercury	57,9	0,39		0,38	3,30	0,05	5,43		59 days		0,11	3,70	4,4	Is absent
Venus	108,2	0,72		0,95	48,68	0,89	5,25		243 days		0,65	8,87	10,4	CO 2, N 2, H 2 O
Earth	149,6	1,0		1,0	59,74	1,0	5,52	365,26	23 h 56 min 4 s		0,37	9,78	11,2	N 2, O 2, CO 2, Ar, H 2 O
Moon		1,0		0,27	0,74	0,0123	3,34	29,5	27 h 32 min	-	0,12	1,63	2,4	Very discharged	-20
Mars	227,9	1,5		0,53	6,42	0,11	3,95		24 h 37 min 23 s		0,15	3,69	5,0	CO 2 (95.3), N 2 (2.7), Ar (1.6), O 2 (0.15), H 2 O (0.03)	-53
Jupiter	778,3	5,2			18986,0		1,33	11.86 years	9 h 30 min 30 s		0,52	23,12	59,5	H (77), Not (23)	-128
Saturn	1429,4	9,5			5684,6		0,69	29.46 years	10 h 14 min		0,47	8,96	35,5	H, Not	-170
Uranus	2871,0	19,2	25 362		868,3		1,29	84.07 years	11 h3		0,51	8,69	21,3	H (83), He (15), CH 4 (2)	-143
Neptune	4504,3	30,1	24 624		1024,3		1,64	164.8 years	16h		0,41	11,00	23,5	H, He, CH 4	-155
Pluto	5913,5	39,5		0,18	0,15	0,002	2,03	247,7	6.4 days		0,30	0,66	1,3	N 2, CO, NH 4	-210

The sunis an incandescent gas sphere containing about 60 chemical elements (Table 3.2). The sun rotates around its axis in a plane inclined at an angle of 7 ° 15 "to the plane of the earth's orbit. The rotation speed of the surface layers of the sun is different: at the equator, the orbital period is 25.05 days, at a latitude of 30 ° - 26.41 days, in the polar regions - 36 days. The source of the Sun's energy is nuclear reactions that convert hydrogen into helium. The amount of hydrogen will ensure the preservation of its luminosity for tens of billions of years. The Earth receives only one two-billionth part of solar energy.

The sun has a shell structure (Fig. 3.2). In the center there are nucleuswith a radius of about 1/3 solar, a pressure of 250 billion atm, a temperature of more than 15 million K and a density of 1.5 × 10 5 kg / m 3 (150 times the density of water). Almost all of the Sun's energy is generated in the core, which is transmitted through radiation zone,where light is repeatedly absorbed by matter and re-emitted. Above is convection zone(stirring), in which the substance comes into motion due to the uneven transfer of heat (a process similar to the transfer of energy in a boiling kettle). The visible surface of the Sun is formed by its atmosphere.Its lower part with a thickness of about 300 km, emitting the bulk of the radiation, is called photosphere.It is the "coldest" place on the Sun with temperatures dropping from 6000 to 4500 K in the upper layers. The photosphere is formed by granules with a diameter of 1000-2000 km, the distance between which is from 300 to 600 km. Granules create a general background for various solar formations - prominences, torches, spots. Above the photosphere up to an altitude of 14 thousand km is located chromosphere.During total lunar eclipses, it is visible as a pink nimbus surrounding a dark disk. The temperature in the chromosphere increases and in the upper layers reaches several tens of thousands of degrees. The outermost and most rarefied part of the solar atmosphere - sun crown- extends over distances of several tens of solar radii. The temperature here exceeds 1 million degrees.

Table 3.2. Chemical composition of the Sun and terrestrial planets,% (according to A.A.Marakushev, 1999)

Element	The sun	Mercury	Venus	Earth	Mars
Si	34,70	16,45	33,03	31,26	36,44
Fe	30,90	63,07	30,93	34,50	24,78
Mg	27,40	15,65	31,21	29,43	34,33
Na	2,19	-	-	-	-
Al	1,74	0,97	2,03	1,90	2,29
Ca	1,56	0,88	1,62	1,53	1,73
Ni	0,90	2,98	1,18	1,38	0,43

Figure: 3.2. The structure of the sun

PlanetsThe solar systems are classified into two groups: internal,or terrestrial planets - Mercury, Venus, Earth, Mars, and external,or the giant planets - Jupiter, Saturn, Uranus, Neptune and Pluto. The estimated material composition of the planets is shown in Fig. 3.3.

Terrestrial planets.The inner planets are relatively small in size, high density and internal differentiation of matter. They are distinguished by an increased concentration of carbon, nitrogen and oxygen, a lack of hydrogen and helium. For the terrestrial planets, tectonic asymmetry is characteristic: the structure of the crust of the northern hemispheres of the planets differs from the southern ones.

Mercury -the planet closest to the Sun. Among the planets of the solar system, it is distinguished by the most elongated elliptical orbit. The temperature on the illuminated side is 325-437 ° C, on the night side - from -123 to -185 ° C. The American spacecraft "Mariner-10" in 1974 discovered on Mercury a rarefied atmosphere (pressure 10 -11 atm), consisting of helium and hydrogen in a ratio of 50: 1. Mercury's magnetic field is 100 times weaker than Earth's, which is largely due to the planet's slow rotation around its axis. The surface of Mercury has much in common with the surface of the Moon, but the mainland relief prevails. Along with lunar-like craters of various sizes, there are scarps absent on the Moon - cliffs with a height of 2-3 km and a length of hundreds and thousands of kilometers.

Figure: 3.3. The structure and the estimated material composition of the planets (according to G.V. Voitkevich): and -terrestrial group: 1, 2, 3 - silicate, metallic, sulfide-metallic substances, respectively; b- giants: 1 - molecular hydrogen; 2 - metallic hydrogen; 3 - water ice; 4 - a core composed of stone or iron-stone material

The mass of Mercury is 1/18 of the mass of the Earth. Despite its small size, Mercury has an unusually high density (5.42 g / cm 3), close to the density of the Earth. High density indicates the presence of a hot, and probably molten, metallic core, which accounts for about 62% of the planet's mass. The core is surrounded by a silicate shell about 600 km thick. The chemical composition of the surface rocks and bowels of Mercury can be judged only by indirect data. The reflectivity of the Mercurian regolith indicates that it consists of the same rocks that compose the lunar soil.

Venusturns around its axis even more slowly (in 244 Earth days) than Mercury, and in the opposite direction, so the Sun on Venus rises in the west and sets in the east. The mass of Venus is 81% earth mass... The weight of objects on Venus is only 10% less than their weight on Earth. It is believed that the planet's crust is thin (15-20 km) and its main part is represented by silicates, which are replaced by an iron core at a depth of 3224 km. The relief of the planet is dismembered - mountain ranges up to 8 km in height alternate with craters tens of kilometers in diameter (up to 160 km maximum) and up to 0.5 km deep. Vast leveled areas are covered with stony placers of acute-angled fragments. Near the equator, a giant linear depression up to 1500 km long and 150 km wide at a depth of up to 2 km was discovered. Venus does not have a dipole magnetic field, which is explained by its high temperature. On the surface of the planet, the temperature is (468 + 7) ° С, and at a depth, obviously, - 700-800 ° С.

Venus has a very dense atmosphere. On the surface, the atmospheric pressure is at least 90-100 atm, which corresponds to the pressure of the earth's seas at a depth of 1000 m. In terms of chemical composition, the atmosphere consists mainly of carbon dioxide with an admixture of nitrogen, water vapor, oxygen, sulfuric acid, hydrogen chloride and fluoride. It is believed that the atmosphere of Venus roughly corresponds to that of Earth in the early stages of its formation (3.8-3.3 billion years ago). The cloud layer of the atmosphere extends from a height of 35 km to 70 km. The lower layer of clouds consists of 75-80% sulfuric acid, in addition, hydrofluoric and hydrochloric acids are present. Being 50 million km closer to the Earth from the Sun, Venus receives twice as much heat as our planet - 3.6 cal / (cm 2 min). This energy is accumulated by the carbon dioxide atmosphere, which causes a huge greenhouse effect and high temperatures of the Venusian surface - hot and, apparently, dry. Space information indicates a peculiar glow of Venus, which is probably due to the high temperatures of the surface rocks.

Venus is characterized by complex cloud dynamics. It is likely that powerful polar vortices and strong winds exist at an altitude of about 40 km. Near the planet's surface, the winds are weaker - about 3 m / s (apparently due to the absence of significant changes in the near-surface temperature), which is confirmed by the absence of dust in the landing sites of the descent vehicles of the Venera stations. For a long time, the dense atmosphere did not allow judging the rocks of the Venusian surface. Analysis of the natural radioactivity of isotopes of uranium, thorium and potassium in soils showed results close to terrestrial basalts and partially granites. Surface rocks are magnetized.

Marsis located 75 million km farther from the Sun than the Earth, therefore the Martian day is longer than the Earth's, and solar energy comes to it 2.3 times less than the Earth. The period of revolution around the axis is almost like that of the Earth. The inclination of the axis to the orbital plane ensures the change of seasons and the presence of "climatic" zones - hot equatorial, two temperate and two polar. Due to the small amount of incoming solar energy, the contrasts of heat zones and seasons of the year are less pronounced than the earthly ones.

The density of the Mars atmosphere is 130 times less than that of the Earth and is equal to only 0.01 atm. The atmosphere contains carbon dioxide, nitrogen, argon, oxygen, and water vapor. Daily temperature fluctuations exceed 100 ° С: at the equator during the day - about 10-20 °, and at the poles - below -100 ° С. Large differences in temperature are observed between the day and night sides of the planet: from 10-30 to -120 ° C. At an altitude of about 40 km, Mars is surrounded ozone layer... A weak dipole magnetic field is noted for Mars (at the equator it is 500 times weaker than the Earth's).

The planet's surface is pitted with numerous craters of volcanic and meteorite origin. The altitude changes are on average 12-14 km, but the huge caldera of the Nyx Olympics volcano (Snow Olympus) rises by 24 km. The diameter of its base is 500 km, and the diameter of the crater is 65 km. Some volcanoes are active. A feature of the planet is the presence of huge tectonic cracks (for example, the Mariner Canyon 4000 km long and 2000 km wide at a depth of up to 6 km), resembling terrestrial grabens and morphosculptures corresponding to river valleys.

The images of Mars show areas with a light color ("continental" areas, apparently composed of granites), yellow ("sea" areas, apparently composed of basalts) and a snow-white appearance (ice caps). Observations of the polar regions of the planet have established the variability of the outlines of the ice massifs. Scientists hypothesize that the polar ice caps are composed of frozen carbon dioxide and possibly water ice. The reddish color of the surface of Mars is probably due to hematitization and limonitization (oxidation of iron) of rocks, which are possible in the presence of water and oxygen. Obviously, they come from the inside when the surface is warmed up in the daytime or with gas exhalations that melt the permafrost.

The study of rocks showed the following ratio of chemical elements (%): silica - 13-15, iron oxides - 12-16, calcium - 3-8, aluminum - 2-7, magnesium - 5, sulfur - 3, as well as potassium, titanium , phosphorus, chromium, nickel, vanadium. Mars' soil is similar in composition to some terrestrial volcanic rocks, but enriched in iron compounds and depleted in silica. No organic formations were found on the surface. In the near-surface layers of the planet (from a depth of 50 cm), the soils are bound by permafrost, extending up to 1 km in depth. In the bowels of the planet, the temperature reaches 800-1500 ° C. It is assumed that at a shallow depth the temperature should be 15-25 ° C, and the water can be in a liquid state. Under these conditions, the simplest living organisms can exist, traces of their vital activity have not yet been found.

Mars has two satellites - Phobos (27x21x19 km) and Deimos (15x12x11 km), which are obviously asteroid fragments. The orbit of the first passes 5000 km from the planet, the second - 20 000 km.

Table 3.2 shows the chemical composition of the terrestrial planets. The table shows that Mercury is characterized by the highest concentrations of iron and nickel and the lowest silicon and magnesium.

The giant planets.Jupiter, Saturn, Uranus and Neptune differ markedly from the terrestrial planets. In the giant planets, especially in those closest to the Sun, the full angular momentum of the solar system (in units of the Earth) is concentrated: Neptune - 95, Uranus - 64, Saturn - 294, Jupiter - 725. The remoteness of these planets from the Sun allowed them to preserve a significant amount primary hydrogen and helium, lost by the terrestrial planets under the influence of the "solar wind" and due to the lack of their own gravitational forces. Although the density of matter outer planets small (0.7-1.8 g / cm 3), their volumes and masses are huge.

The largest planet is Jupiter, 1300 times in volume and more than 318 times the mass of Earth. It is followed by Saturn, whose mass is 95 times the mass of the Earth. These planets contain 92.5% of the mass of all planets in the solar system (71.2% for Jupiter and 21.3% for Saturn). The group of outer planets is closed by two giant twins - Uranus and Neptune. An important feature is the presence of stone satellites in these planets, which probably indicates their outer cosmic origin and is not associated with the differentiation of the matter of the planets themselves, formed by condensations mainly in a gaseous state. Many researchers believe that the central parts of these planets are solid.

Jupiterwith characteristic spots and stripes on the surface, which are parallel to the equator and have variable outlines, it is the most accessible planet for exploration. Jupiter's mass is only two orders of magnitude less than the Sun's. The axis is almost perpendicular to the orbital plane.

Jupiter has a powerful atmosphere and a strong magnetic field (10 times stronger than the Earth's), which determines the presence of powerful radiation belts around the planet of protons and electrons captured by the magnetic field of Jupiter from the "solar wind". The atmosphere of Jupiter, in addition to molecular hydrogen and helium, contains a variety of impurities (methane, ammonia, carbon monoxide, water vapor, phosphine molecules, hydrogen cyanide, etc.). The presence of these substances is possibly a consequence of the assimilation of dissimilar material from the Cosmos. The stratified hydrogen-helium mass reaches a thickness of 4000 km and, due to the uneven distribution of impurities, forms stripes and spots.

The huge mass of Jupiter suggests the presence of a powerful liquid or semi-liquid core of the asthenospheric type, which can be a source of volcanism. The latter, in all likelihood, explains the existence of the Great Red Spot, which has been observed since the 17th century. In the presence of a semi-liquid or solid core body, the planet must have a strong greenhouse effect.

According to some scientists, Jupiter plays the role of a kind of "vacuum cleaner" in the solar system - its powerful magnetic-gravitational field intercepts comets, asteroids and other bodies wandering in the Universe. A vivid example was the capture and fall of comet Shoemaker-Levy-9 on Jupiter in 1994. The force of gravity was so great that the comet split into separate fragments, which crashed into Jupiter's atmosphere at a speed of over 200 thousand km / h. Each explosion reached a power of millions of megatons, and observers from Earth saw the spots of the explosions and the diverging waves of the excited atmosphere.

At the beginning of 2003, the number of satellites of Jupiter reached 48, a third of which have their own names. Many of them are characterized by reverse rotation and small sizes - from 2 to 4 km. The four largest moons - Ganymede, Callisto, Io, Europa - are called the Galilee. The satellites are composed of solid stone material, apparently of silicate composition. Active volcanoes, traces of ice and possibly liquids, including water, were found on them.

Saturn,The "ringed" planet is of no less interest. Its average density, calculated from the apparent radius, is very low - 0.69 g / cm 3 (without atmosphere - about 5.85 g / cm 3). The thickness of the atmospheric layer is estimated at 37-40 thousand km. A distinctive feature of Saturn is the ring located above the cloudy layer of the atmosphere. Its diameter is 274 thousand km, which is almost twice the diameter of the planet, and its thickness is about 2 km. According to observations from space stations, it has been established that the ring consists of a number of small rings located at different distances from each other. The material of the rings is represented by hard fragments, obviously, silicate rocks and ice blocks ranging in size from a dust grain to several meters. The atmospheric pressure on Saturn is 1.5 times that of the Earth, and the average surface temperature is about -180 ° C. The magnetic field of the planet is almost half the strength of the earth, and its polarity is opposite to the polarity of the earth's field.

30 satellites have been found near Saturn (as of 2002). The most distant of them - Phoebe (diameter of 110 km) is located 13 million km from the planet and turns around it in 550 days. The closest one - Mimas (diameter 195 km) is located at 185.4 thousand km and makes a complete revolution in 2266 hours. The mystery is the presence of hydrocarbons on the moons of Saturn, and possibly on the planet itself.

Uranus.The axis of rotation of Uranus is located almost in the plane of the orbit. The planet has a magnetic field, the polarity of which is opposite to that of the earth, and the intensity is less than that of the earth.

In the dense atmosphere of Uranus, the thickness of which is 8500 km, ring formations, spots, vortices, jet currents were found, which indicates a restless circulation of air masses. The directions of the winds generally coincide with the rotation of the planet, but at high latitudes their speed increases. The greenish-blue color of the cold atmosphere of Uranus may be due to the presence of radicals [OH -]. The content of helium in the atmosphere reaches 15%, methane clouds are found in the lower layers.

Around the planet, 10 rings were discovered, ranging from several hundred meters to several kilometers wide, consisting of particles about 1 m in diameter. Inside the rings, stones are moving irregularly shaped and 16-24 km in diameter, called satellites-"shepherds" (probably asteroids).

Among the 20 satellites of Uranus, five stand out for their significant sizes (from 1580 to 470 km in diameter), the rest are less than 100 km. They all look like asteroids captured by Uranus's gravitational field. On the spherical surface of some of them, giant linear stripes are seen - cracks, possibly traces of glancing impacts of meteorites.

Neptune- the planet farthest from the Sun. The clouds in the atmosphere are mainly formed by methane. In the upper layers of the atmosphere, wind flows are observed, rushing at a supersonic speed. This means the existence of temperature and pressure gradients in the atmosphere, apparently caused by the internal heating of the planet.

Neptune has 8 stone satellites, three of which are of significant size: Triton (2700 km in diameter), Neris (340 km) and Proteus (400 km), the rest are smaller - from 50 to 190 km.

Pluto- the farthest of the planets, discovered in 1930, does not belong to the giant planets. Its mass is 10 times less than the earth's.

Rotating rapidly around its axis, Pluto has a highly elongated elliptical orbit, and therefore from 1969 to 2009 it will be closer to the Sun than Neptune. This fact can be additional proof of its "non-planetary" nature. It is likely that Pluto belongs to bodies from the Kuiper belt, discovered in the 90s of the XX century, which is an analogue of the asteroid belt, but beyond the orbit of Neptune. At present, about 40 such bodies have been found with a diameter of 100 to 500 km, very dim and almost black, with an albedo of 0.01 - 0.02 (the Moon has an albedo of 0.05). Pluto is possibly one of them. The planet's surface is obviously icy. Pluto has a single satellite, Charon, 1190 km in diameter, with an orbit passing 19 thousand km from it and an orbital period of 6.4 Earth days.

By the nature of the motion of the planet Pluto, researchers suggest the presence of another extremely distant and small (tenth) planet. At the end of 1996, it was reported that astronomers from the Hawaiian Observatory had discovered a celestial body composed of ice blocks, which orbits in a circumsolar orbit beyond Pluto. This minor planet does not yet have a name and is registered under the number 1996TL66.

Moon- a satellite of the Earth, rotating from it at a distance of 384 thousand km, whose size and structure bring it closer to the planets. The periods of axial and sidereal rotation around the Earth are almost equal (see Table 3.1), which is why the Moon is always facing us with one side. The view of the moon for an earthly observer is constantly changing in accordance with its phases - new moon, first quarter, full moon, last quarter.The period of the complete change of the lunar phases is called synodic month,which is on average 29.53 Earth days. It does not match sidereal(starry) month,constituting 27.32 days, during which the Moon makes a complete revolution around the Earth and at the same time - a revolution around its axis in relation to the Sun. On a new moon, the Moon is between the Earth and the Sun and is not visible from Earth. During a full moon, the Earth is between the Moon and the Sun and the Moon is visible as a full disk. Associated with the positions of the Sun, Earth and Moon solarand lunar eclipses- the positions of the luminaries at which the shadow cast by the Moon falls on the surface of the Earth (solar eclipse), or the shadow cast by the Earth falls on the surface of the Moon (lunar eclipse).

The lunar surface is an alternation of dark areas - "seas" corresponding to flat plains, and light areas - "continents" formed by hills. The height differences reach 12-13 km, the highest peaks (up to 8 km) are located at the South Pole. Numerous craters ranging in size from several meters to hundreds of kilometers are of meteoric or volcanic origin (in 1958, the glow of the central hill and the release of carbon were discovered in the Alphonse crater). The intense volcanic processes inherent in the Moon in the early stages of development are now weakened.

Samples of the upper layer of lunar soil - regolith,taken by Soviet spacecraft and American astronauts, showed that igneous rocks of basic composition - basalts and anorthosites - emerge on the lunar surface. The former are typical for the "seas", the latter for the "continents". The low density of the regolith (0.8-1.5 g / cm 3) is explained by its high porosity (up to 50%). The average density of darker "sea" basalts is 3.9 g / cm 3, and the lighter "continental" anorthosites - 2.9 g / cm 3, which is higher than the average density of rocks in the earth's crust (2.67 g / cm 3) ... The average density of the lunar rocks (3.34 g / cm 3) is lower than the average density of the earth's rocks (5.52 g / cm 3). A homogeneous structure of its interior and, apparently, the absence of a significant metal core is assumed. To a depth of 60 km, the lunar crust is composed of the same rocks as the surface. The moon has not found its own dipole magnetic field.

In terms of chemical composition, lunar rocks are close to terrestrial ones and are characterized by the following indicators (%): SiO 2 - 49.1 - 46.1; MgO 6.6-7.0; FeO - 12.1-2.5; A1 2 O 3 - 14.7-22.3; CaO -12.9-18.3; Na 2 O - 0.6-0.7; TiO 2 - 3.5-0.1 (the first figures are for the soil of the lunar "seas", the second - for the continental soil). The close similarity of the rocks of the Earth and the Moon may indicate that both celestial bodies were formed at a relatively small distance from each other. The moon formed in a near-Earth "satellite swarm" about 4.66 billion years ago. The bulk of iron and low-melting elements at that time was already captured by the Earth, which probably determined the absence of an iron core in the Moon.

The small mass allows the Moon to hold only a very rarefied atmosphere, consisting of helium and argon. The atmospheric pressure on the Moon is 10 -7 atm in the daytime and ~ 10 -9 atm at night. The absence of atmosphere determines large daily fluctuations in surface temperature - from -130 to 180C.

Exploration of the Moon began on January 2, 1959, when the first Soviet automatic station Luna-1 was launched towards the Moon. The first people were American astronauts Neil Armstrong and Edwin Aldrin, who landed on July 21, 1969 in the Apollo 11 spacecraft.

If you ask any of us about the place of residence, then the answer, most likely, will be the name of the city or village, street, house, apartment. Maybe someone will name another country, well, or some other joker will say that he lives on planet Earth. This is how we live on Earth, and not all of us know what place it occupies in the vast Universe. Our Earth will be the first point of our astronomical address. This is a rather unusual planet that has a unique composition of the atmosphere, huge oceans on its surface, is protected from external radiation by a powerful magnetic field, the ozone layer and the ionosphere. The Earth is at a distance of 1 astronomical unit from the Sun. It is easy to guess that the very concept of an astronomical unit arose as a certain reference value. If we translate this distance into kilometers, then we get the distance of the maximum distance of the Earth from the Sun - Aphelios, equal to about 152 million kilometers. This is how far our planet is from the Sun. Or is it close?
Apparently, it is still close, because, for example, Pluto, which is located almost on the border of our solar system, is already located at a distance of 12 billion kilometers, or 80 astronomical units. Such is our huge planetary system. Moreover, the main place in it is occupied not by the planets, but by our Star - the Sun, which makes up about 99 percent of the mass of the entire solar system. It is easy to calculate that all the planets, including not only the tiny Earth, but also the giant Jupiter, make up less than one percent of its mass. And it really makes you think about our place in the universe. In the solar system, the Earth, despite all its features, is only one of the planets of the Terrestrial group, which, in addition to it, also includes Mercury, Venus and Mars.
From the Sun to the Milky Way
But let's move on - we realized that we are among the planets of the Terrestrial group, in the solar system, which is based on the star Sun. To better understand all the scales, it is worth noting that our Sun, which looks like a small bright lantern from the Earth, actually has a diameter equal to almost 109 times the Earth's diameter. "What a huge sun!" - the thought comes to mind. However, by the standards of the galaxy, it is just an ordinary yellow dwarf, a very small and inconspicuous star. Among the bright tribe of stars, there are colossal red giants that are thousands of times larger than the Sun. These are the scales!
Of course, the Sun is also included in some even larger system. And such a system is our galaxy - the Milky Way. It is part of it that is visible on a clear moonless night, like a foggy strip passing through the entire sky. If we look at this strip through binoculars, we will see a huge number of stars. Indeed, in our galaxy, in addition to the Sun, there are about 200 billion more stars, although some scientists are of the opinion that there are twice as many. All of these stars make up a huge spiral that revolves around its center.
Our Sun occupies a far from central position in this stellar placer, being in one of the spiral branches - in the Orion arm. And, like billions of other stars, it revolves around the center of the galaxy. In this case, the Sun is closer to the periphery at a distance of about 26 thousand light years from this center. That is, if you fly there at the speed of light, then thousands of years will pass before we get to the core of the Galaxy.
From the Galaxy to infinity
So we got to the huge Milky Way galaxy, 100 thousand light years in diameter, which, in the form of a spiral disk, consisting of a myriad of stars, sweeps through space and time. But our galaxy is not alone in the universe. There are a huge number of them - modern astronomers can currently observe 100 billion galaxies. But, apparently, there are many more.
Our galaxy has neighbors - the Large and Small Magellanic clouds and the Andromeda galaxy. Together with its neighbors, the Milky Way belongs to the local group of galaxies. In addition to those listed, it includes about 50 other systems.
The local group of galaxies, in turn, is part of the Virgo supercluster of galaxies, which spans galaxies within a radius of 200 million light years and contains about thirty thousand galaxies.
The scale is amazing, introduces a kind of reverence for the grandeur of such systems. But what's next? Further, we can select that part of the Universe that we can observe in all devices available to us - it is called the Metagalaxy. Next comes the entire Universe as a whole, the presence of boundaries at which modern physics, although it recognizes, but their exact definition is still only at a hypothetical level.

Planet Earth, solar system, and all the stars visible to the naked eye are in Milky Way Galaxy, which is a barred spiral galaxy with two pronounced arms starting at the ends of the bar.

This was confirmed in 2005 by the Lyman Spitzer Space Telescope, which showed that the central bar of our galaxy is larger than previously thought. Spiral galaxies with a bar - spiral galaxies with a bar (“bar”) of bright stars emerging from the center and crossing the galaxy in the middle.

Spiral branches in such galaxies start at the ends of the barriers, whereas in ordinary spiral galaxies they exit directly from the core. Observations show that about two-thirds of all spiral galaxies are barred. According to existing hypotheses, the bridges are centers of star formation that support the birth of stars in their centers. It is assumed that through orbital resonance, they let gas through them from the spiral arms. This mechanism provides an influx of building material for the birth of new stars. The Milky Way along with the Andromeda Galaxy (M31), the Triangle (M33), and more than 40 smaller satellite galaxies form the Local Group of Galaxies, which in turn is part of the Virgo Supercluster. "Using an infrared image from NASA's Spitzer telescope, scientists have discovered that the Milky Way's elegant spiral structure has only two dominant arms from the ends of the central bar of stars. Our galaxy was previously thought to have four major arms."

/s.dreamwidth.org/img/styles/nouveauoleanders/titles_background.png "target \u003d" _blank "\u003e http://s.dreamwidth.org/img/styles/nouveauoleanders/titles_background.png) 0% 50% no-repeat rgb (29, 41, 29); "\u003e Structure of the Galaxy
In appearance, the galaxy resembles a disk (since most of the stars are located in the form of a flat disk) with a diameter of about 30,000 parsecs (100,000 light years, 1 quintillion kilometers) with an estimated average disk thickness of about 1,000 light years, the diameter of the bulge is the center of the disk is 30,000 light years. The disk is immersed in a spherical halo, and a spherical crown is located around it. The Galactic nucleus center is located in the constellation Sagittarius. The thickness of the galactic disk where it is solar system with planet Earth is 700 light years. The distance from the Sun to the center of the Galaxy is 8.5 kilo parsecs (2.62.1017 km, or 27,700 light years). solar system is located on the inner edge of the arm called the Orion arm. In the center of the Galaxy, apparently, there is a super massive black hole (Sagittarius A *) (about 4.3 million solar masses) around which, presumably, a black hole with an average mass of 1000 to 10,000 solar masses and an orbital period of about 100 years revolves and several thousand comparatively small ones. The galaxy contains, according to the lowest estimate, about 200 billion stars (current estimates range from 200 to 400 billion). As of January 2009, the mass of the Galaxy is estimated at 3.1012 solar masses, or 6.1042 kg. The bulk of the Galaxy is contained not in stars and interstellar gas, but in a non-luminous halo of dark matter.

Compared to the halo, the disk of the Galaxy rotates noticeably faster. Its rotation speed is not the same at different distances from the center. It rapidly increases from zero at the center to 200-240 km / s at a distance of 2 thousand light years from it, then decreases slightly, increases again to approximately the same value, and then remains almost constant. The study of the features of the rotation of the disk of the Galaxy made it possible to estimate its mass; it turned out that it is 150 billion times greater than the mass of the Sun. Age Milky Way Galaxy is equal13,200 million years old, almost as old as the universe. The Milky Way is part of the Local Group of Galaxies.

/s.dreamwidth.org/img/styles/nouveauoleanders/titles_background.png "target \u003d" _blank "\u003e http://s.dreamwidth.org/img/styles/nouveauoleanders/titles_background.png) 0% 50% no-repeat rgb (29, 41, 29); "\u003e Location of the Solar System solar system is located on the inner edge of an arm called the Orion arm, in the marginal part of the Local Supercluster, sometimes also called the Virgo Super Cluster. The thickness of the galactic disk (where it is solar system with the planet Earth), is 700 light years. The distance from the Sun to the center of the Galaxy is 8.5 kilo parsecs (2.62.1017 km, or 27,700 light years). The sun is located closer to the edge of the disk than to its center.

Together with other stars, the Sun revolves around the center of the Galaxy at a speed of 220-240 km / s, making one revolution in about 225-250 million years (which is one galactic year). Thus, during its entire existence, the Earth has flown around the center of the Galaxy no more than 30 times. The galactic year of the Galaxy is 50 million years, the orbital period of the bar is 15-18 million years. In the vicinity of the Sun, it is possible to track sections of two spiral arms, which are approximately 3 thousand light years distant from us. According to the constellations where these areas are observed, they were named the Sagittarius arm and the Perseus arm. The sun is located almost midway between these spiral branches. But relatively close to us (by galactic standards), in the constellation Orion, there is another, not very clearly expressed arm - the Orion arm, which is considered an offshoot of one of the main spiral arms of the Galaxy. The speed of rotation of the Sun around the center of the Galaxy almost coincides with the speed of the compaction wave that forms the spiral arm. This situation is atypical for the Galaxy as a whole: the spiral arms rotate at a constant angular velocity, like spokes in wheels, and the movement of stars occurs with a different pattern, therefore, almost the entire stellar population of the disk either falls into the spiral arms or falls out of them. The only place where the speeds of stars and spiral arms coincide is the so-called corotation circle, and it is on this circle that the Sun is located. For the Earth, this circumstance is extremely important, since violent processes occur in the spiral arms, forming powerful radiation, destructive for all living things. And no atmosphere could protect against him. But our planet exists in a relatively quiet place in the Galaxy and has not been exposed to these cosmic cataclysms for hundreds of millions (or even billions) years. Perhaps this is why life on Earth was able to be born and survive, the age of which is 4.6 billion years. Diagram of the location of the Earth in the universe in a series of eight maps that show, from left to right, starting with the Earth, moving in Solar system, to neighboring star systems, to the Milky Way, to local Galactic groups, tolocal Virgo superclusters, on our local super-cluster, and ends up in the observable universe.

Solar system: 0.001 light years

Neighbors in interstellar space

Milky Way: 100,000 light years

Local Galactic Groups

Local Super Cluster Virgo

Local over the galaxy cluster

Observable Universe