Planets of the solar system. VENUS.

Heavenly neighbor.

The most beautiful and closest of the planets - Venus - has been riveting a person's gaze to itself for millennia. How many brilliant poems Venus has produced! No wonder she bears the name of the goddess of love. But no matter how much scientists study our nearest neighbor in the solar system, the number of questions that are just waiting for their Columbus does not decrease. The planet is full of mysteries and wonders. The semi-major axis of the orbit of Venus - the average distance from the Sun - is 0.723 AU. (108.2 million km). The orbit is almost circular, its eccentricity is 0.0068 - the smallest in the solar system. Orbital inclination to the plane of the ecliptic: i \u003d 3 ° 39 ". Venus is the closest planet to Earth - the distance to it varies from 40 to 259 million kilometers. The average orbital speed is 35 km / s. The orbital period is 224.7 Earth days, and the period of rotation around the axis is 243.02 Earth days.In this case, Venus rotates in the direction opposite to its orbital movement (when viewed from the north pole of Venus, the planet rotates clockwise, and not counterclockwise, like the Earth and the rest planets except Uranus; inclination of equator to orbit: 177°18"). This leads to the fact that a day on Venus lasts 116.8 Earth days (half a Venusian year). Thus, day and night on Venus last for 58.4 Earth days. The mass of Venus is 0.815M of the mass of the Earth (4.87.10 24 kg). The planet has no satellites, so the mass of Venus was refined from the flybys of the planet by the American spacecraft Mariner-2, Mariner-5 and Mariner-10. The density of our neighbor is 5.24 g/cm 3 . The radius of Venus - 0.949 R (6052 km) - was measured in the sixties by radar methods: the surface of the planet is constantly covered with dense clouds. Venus is almost spherical. The free fall acceleration on the surface is 8.87 m/s 2 .

Venus in the sky.

Venus is easily recognizable as it is far superior in brilliance to the brightest of the stars. A distinctive feature of the planet is its even white color. Venus, like Mercury, does not recede in the sky at a great distance from the Sun. At times of elongation, Venus can move away from our star by a maximum of 48 °. Like Mercury, Venus has periods of morning and evening visibility: in ancient times, it was believed that morning and evening Venus were different stars. Venus is the third brightest object in our sky. During periods of visibility, its brightness is at its maximum at about m = -4.4.

Orbit of Venus.

In 1610, Galileo in the telescope he invented for the first time observed a change in the visible phase of the planet's disk. The mechanism of phase change is the same as for the Moon. People with the sharpest eyesight can sometimes make out the crescent of Venus with the naked eye. In 1761, Mikhail Lomonosov, observing the passage of Venus across the disk of the Sun, noticed a thin iridescent rim that surrounded the planet. This is how the atmosphere of Venus was discovered. This atmosphere is extremely powerful: the pressure at the surface turned out to be 90 atmospheres. At the bottom of the Diana Canyon, it reaches 119 bar. The high temperature of the lower atmosphere of Venus is explained by the greenhouse effect.

The greenhouse effect also occurs in the atmospheres of other planets. But if in the atmosphere of Mars it raises the average temperature near the surface by 9°, in the atmosphere of the Earth - by 35°, then in the atmosphere of Venus this effect reaches 400 degrees! The recorded maximum temperature on the surface is +480°C.

Venus clouds in ultraviolet rays. The contrast is greatly increased. Rice. left.

In 1932, W. Adams and T. Wilson proved that the atmosphere of Venus is 96.5% carbon dioxide. No more than 3% is accounted for by nitrogen; in addition, impurities of inert gases (first of all, argon) were found. Traces of oxygen, water, hydrogen chloride and hydrogen fluoride were found. It was assumed that due to dense clouds on the surface of Venus it is always dark. However, "Venera-8" showed that the illumination of the day side of Venus is approximately the same as on Earth on a cloudy day.

The internal structure of Venus.

The sky on Venus has a bright yellow-green hue.

The foggy haze extends to a height of about 50 km. Further, up to a height of 70 km, clouds of small drops of concentrated sulfuric acid go. There are also impurities of hydrochloric acid and hydrofluoric acid. It is believed that sulfuric acid in the atmosphere of Venus is formed from sulfur dioxide, the source of which may be the volcanoes of Venus. The speed of rotation at the level of the upper boundary of the clouds is different than above the very surface of the planet. This means that over the equator of Venus, at an altitude of 60-70 km, a hurricane wind is constantly blowing at a speed of 100 m/s and even 300 m/s in the direction of the planet's motion. At high latitudes of Venus, the wind speed at high altitudes decreases, and there is a polar vortex near the poles. The uppermost layers of Venus's atmosphere are composed almost entirely of hydrogen. The hydrogen atmosphere of Venus extends to an altitude of 5500 km. The temperature of the cloud layers ranges from -70°C to -40°C. Venus has a liquid iron core, but it does not generate a magnetic field, probably due to Venus' slow rotation. AMS "Venera-15" and "Venera-16" with the help of radar found mountain peaks on Venus with clear traces of lava flows. Currently, about 150 volcanic objects have been registered, the size of which exceeds 100 km; the total number of volcanoes on the planet is estimated at 1600. Volcanic eruptions generate powerful electrical discharges. Venusian thunderstorms have been repeatedly recorded by AMS instruments. Volcanism on Venus testifies to the activity of its bowels. The convective flows of the liquid mantle are blocked by a thick basalt shell. The composition of the rocks includes oxides of silicon, aluminum, magnesium, iron, calcium and other elements.

Venus comes closer to Earth than all the other planets. However, the dense cloudy atmosphere does not allow one to see its surface directly, and all research is carried out using radar or automatic interplanetary stations. Some scientists used to think that the planet was covered by an ocean everywhere. Almost all images of Venus and its surface are made in conditional colors, since the survey was made by radio waves. With the help of radio waves, it was found that Venus rotates in the opposite direction than almost all planets.

The first two automatic stations "Venus" in the sixties could not reach the planet, leaving the trajectory. The following stations collapsed, unable to withstand the harsh conditions of the atmosphere, and only the Venera-7 descent vehicle reached the surface on December 15, 1970 and worked on it for 23 minutes, having managed to conduct a lot of research in the atmosphere, measure the temperature on the surface (about 500 ° C) and pressure (100 atmospheres). The average density of surface rocks is 2.7 g/cm 3 , which is close to the density of terrestrial basalts. The Venera-13 and Venera-14 spacecraft found out that the soil of Venus consists of 50% silica, 16% aluminum alum, and 11% magnesium oxide.

Landscape shot by "Venus-13". In the top photo, the rocks have an orange tint, because. the atmosphere does not transmit blue rays. In the bottom photo, the computer has "removed" the lighting created by the atmosphere, and the rocks are visible in their natural gray. In photographs of the surface of Venus, one can distinguish a rocky desert with characteristic rock formations. Fresh scree of stones and frozen lava flows speak of incessant tectonic activity.

A map of Venus obtained using the Magellan radar.

"Venera-15" and "Venera-16" in 1983 carried out mapping of most of the northern hemisphere using radio waves. The American "Magellan" from 1989 to 1994 produced more detailed (with a resolution of 300 m) and almost complete mapping of the planet's surface. Thousands of ancient volcanoes spewing lava, hundreds of craters, mountains were found on it. The surface layer (bark) is very thin; weakened by heat, it gives many opportunities for lava to escape. Venus is the most active celestial body revolving around the Sun. The two Venusian continents - the Land of Ishtar and the Land of Aphrodite - are no smaller than Europe in area.

The plains of eastern Aphrodite extend for 2200 km and are below average. Lowlands, similar to oceanic depressions, occupy only one-sixth of the surface on Venus. And the Maxwell Mountains on Ishtar Land rise 11 km above the average surface level. By the way, the Maxwell mountains, as well as the regions of Alpha and Beta, are the only exception to the rule adopted by the IAU. All other regions of Venus are given female names: on the map you can find the Lada Land, the Snegurochka Plain and even the Baba Yaga Plain.

Mount Shapash is 400 km wide and 1.5 km high. Shield volcanoes like this one are common on the planet. The relief of 55 regions of Venus was studied. Among them there are sections of both strongly hilly terrain, with elevation changes of 2-3 km, and relatively flat ones. In the northern hemisphere of the planet, a huge round basin has been identified with a length of about 1500 km from north to south and 100 km from west to east. A large plain about 800 km long has been discovered, even smoother than the surface of the lunar seas. It was possible to detect a giant fault in the crust 1500 km long, 150 km wide and 2 km deep. An arc-shaped mountain range, crossed and partially destroyed by another, was revealed.

On the surface of Venus, about 10 ring structures were found, similar to the meteorite craters of the Moon and Mercury, with a diameter of 35 to 150 km, but strongly smoothed, flattened.

A network of cracks in surface rocks through which molten magma tries to break out, swelling the planet's crust.

Impact craters are a rare feature of the Venusian landscape. In the picture on the right, two craters with diameters of about 40-50 km. The inner area is filled with lava. The outward-protruding petals have only been found on Venus. They are heaps of crushed rock thrown out during the formation of a crater.

Venus is the most visible and brightest inhabitant of the earth's sky after the sun and moon. Sometimes it can be observed with the naked eye even in the daytime.

On the distant star Venus // The sun is fiery and golden, // On Venus, ah, on Venus // The trees have blue leaves. (Nikolai Gumilyov)

The distance between Venus and the Sun is approximately 72% of an astronomical unit, the length of the semi-major axis of the earth's orbit. Being an inner planet, Venus never approaches the zenith. Its elongation, the maximum elevation above the horizon, is about 48 degrees. Venus makes a complete revolution around the Sun in almost 225 Earth days.

As Venus orbits between the Earth and the Sun, like Mercury, it changes its appearance from a thin crescent to a full disk. People with very good eyesight can distinguish the phases of Venus even with a simple eye, and they are perfectly visible even in the weakest telescopes. Therefore, it is not surprising that in October 1610 they were observed by Galileo. However, he did not doubt that he would find them, since the presence of phases in any inner planet unambiguously follows from the theory of Copernicus.

Hypsometric map of Venus, compiled at the State Astronomical Institute. Sternberg Moscow State University according to data obtained by the American Magellan spacecraft.

The transit of Venus across the disk of the Sun in 1761 made the first truly non-trivial contribution to our knowledge of this planet. Lomonosov, who observed it, noticed that when the Venusian disk left the solar disk, a brightly luminous ejection appeared and immediately disappeared at the edge of the latter (Lomonosov called it a bump). Mikhailo Vasilievich quite correctly explained this phenomenon by the presence of a "noble air atmosphere" near Venus, which refracts the sun's rays. European astronomers ignored this discovery until it was confirmed by the discoverer of Uranus, William Herschel, and amateur astronomer from Bremen, Johann Schroeter, at the end of the 18th century.

The position when the projection of Venus onto the plane of the earth's orbit falls on the line connecting the Earth and the Sun is called conjunction. Venus is in superior conjunction when the Sun is between it and the Earth, and in inferior conjunction when she is wedged between them. In the lower conjunction, the distance between the planets is reduced to 42 million kilometers, and in the upper one it increases to 258 million. The interval between successive upper and lower conjunctions is called the synodic period of Venus. On average, it is equal to 584 Earth days, although deviations in one direction or another reach hundreds of hours.

Unlike the Earth, Venus does not have mobile lithospheric plates floating on a viscous mantle. The Earth's crust, due to their movements, is updated every hundred million years, and the Venusian, apparently, has not changed five times longer. However, this does not mean that it is stable. Heat flows from the depths of Venus, which gradually heat up the crust and soften its substance. Therefore, the crust periodically becomes plastic and deforms, which causes global changes in the relief. The duration of such cycles, apparently, is at least half a billion years. We also know very little about the internal structure of Venus. It can be studied only with the help of seismic methods, and this requires the creation of long-lived ones - not minutes and hours, but days and weeks! - descent vehicles. By analogy with the Earth, it is generally accepted that the planet consists of a basaltic crust several tens of kilometers thick, a silicate mantle and an iron core with a radius of less than 3000 km.

Observations from Earth

Telescopic observations have always given such fuzzy pictures of the surface of Venus that any attempts to determine the length of the day of this planet with their help have never been successful (for the same reason, cartography of Venus became possible only after it had artificial satellites with radar equipment, although ground-based radio telescopes also managed to do something).

And such attempts were made by almost all astronomers who were interested in this planet. The first of these was the great Giovanni Cassini, who studied Venus even before moving to Paris at his observatory in Bologna. In 1667, he announced that the Venusian day is almost equal to the earth - 23 hours 21 minutes. Over the next 300 years, telescoping astronomers made more than a hundred such estimates - alas, erroneous.

The first color images of Venus obtained by the equipment of the descent vehicle of the Soviet interplanetary station "Venera-13".

The case was helped by the radar of Venus, and even then not immediately. The first experiments of this kind were carried out in the USA (1958) and Great Britain (1959) - but without much success. In May 1961, Soviet newspapers reported that a group of employees of the Institute of Radio Engineering and Electronics of the USSR Academy of Sciences, led by Academician Kotelnik, using an interplanetary radar, established that Venus makes one revolution around its axis in approximately 11 days. Like many others, this estimate turned out to be extremely underestimated. Only a year later, radio physicists from the California Institute of Technology, Goldstein and Carpenter, received an almost correct value - 240 Earth days. In subsequent years, it was repeatedly refined, and now the duration of the Venusian day is considered equal to 243 Earth days (so the day of Venus is longer than its year!). At the same time, it was established that Venus revolves around its axis not from west to east, like the Earth, but from east to west. When viewed from the north pole of the Sun, it turns out that Venus rotates clockwise, and not counterclockwise, like the Earth and other planets (with the exception of Uranus, whose own rotation axis is almost parallel to the orbital plane). Since Venus, like all planets, revolves around the Sun counterclockwise, its orbital and axial angular velocities are opposite in sign. This movement is called retrograde.

In the high layers of the Venusian atmosphere, above the streams of gas circulating in the "superrotation" regime, another circulation is observed. The flow of solar UV radiation on the day side "breaks" carbon dioxide molecules, releasing atomic oxygen, which is transported by the so-called "solar" flows in the thermosphere to the night side of the planet. There, atomic oxygen descends lower into the mesosphere, where it recombines into molecular oxygen, emitting at a wavelength of 1.27 microns. The image is composed of two parts captured by the VIRTIS (Visible and Infrared Thermal Imaging Spectrometer) spectrometer aboard the European Venus Express satellite.

Atmosphere of Venus

The first information about the composition of the Venusian air was obtained exactly a quarter of a century before the beginning of the space age. In 1932, American astronomers Walter Sidney Adams and Theodore Dunham used for this purpose a spectrograph installed on the world's largest 250-cm telescope at the Mount Wilson Observatory. They convincingly proved that the gaseous environment of Venus consists mainly of carbon dioxide. The degree of heating of the upper layer of the Venusian clouds was measured for the first time even earlier, and on the same telescope. Edison Pettit and Seth Nicholson used bolometers to find out that its temperature fluctuates between 33-38°C. These measurements turned out to be surprisingly accurate, and in the future their reliability was repeatedly confirmed.

Other data have already been obtained from spacecraft. We now know that the Venusian air is 96.5% carbon dioxide and 3.5% nitrogen. The remaining components (sulfur dioxide, argon, water vapor, carbon monoxide, helium, hydroxyl groups most recently detected by the Venus Express probe) are present only in small quantities. Nevertheless, atmospheric sulfur is quite enough to form clouds that cover the planet, consisting of sulfur dioxide and aerosol sulfuric acid.

The lower layer of the Venusian atmosphere is almost motionless, but in the troposphere the wind speed exceeds 100 m/s. These storms merge into a single hurricane stream that goes around the planet in four Earth days. It moves in the direction of its rotation (from east to west) and carries dense clouds that circulate around the planet at the same speed (this phenomenon is called superrotation).

Radar imagery taken by the Magellan spacecraft showed that the planet is rife with volcanoes (it is not clear whether they are active or not). On the left is the 400-km mountain Shapash, 1.5 km high, on the right is a volcanic "teak" in the Alpha region with a diameter of 30 km with radial structures extending from it. The picture on the left shows the European station Venus Express orbiting Venus.

Expectations and disappointments

Until the middle of the 20th century, very high expectations were associated with Venus. Before the start of space exploration of this planet, scientists hoped to find on it natural conditions very close to those on Earth, or, more precisely, to those that the Earth went through in the process of its evolution. There were undeniable reasons for this. Both planets are similar in many ways.

Their sizes practically coincide - the equatorial radius of Venus is 6051.8, the Earth - 6378.1 km. The difference between the polar radii is even smaller - 6051.8 and 6356.8 km (Venus is an almost perfect ball, while our planet is somewhat flattened at the poles). The average density of Venusian matter is 95% of that of the earth (5234 and 5515 kg/m3). The acceleration of free fall on the surface of Venus is 8.87 m/s 2 , only 10% less than the earth's. Both Venus and the Earth revolve around the Sun in almost regular circles lying almost in the same plane, the eccentricities of their orbits are 0.0067 and 0.0167, respectively. Moreover, these are the only solid circumsolar planets that have a dense atmosphere. Venus, on a cosmic scale of distances, is located next to the Earth, although, as further studies have shown, this difference in distance from the Sun turned out to be fatal for her. It could be assumed that in terms of their age, Venus and the Earth are quite close, which means that they evolved in a similar way. Popular science magazines have written that Venus is going through a kind of Carboniferous period in its evolution, that it is covered with oceans and full of exotic vegetation. But since the late 1950s, these ideas began to change. With the help of radio telescopes, astronomers measured the so-called brightness temperature of Venus, and it turned out to be significantly higher than expected - by hundreds of degrees. Unlike other terrestrial planets - Mars and Mercury - the surface of Venus is shrouded in a dense cloud layer. Therefore, it was not clear what exactly is the source of such a high temperature. Several models have emerged, some of them associating this temperature with the surface below the clouds, others explaining it with the properties of the ionosphere. These two alternative points of view greatly fueled interest in Venus research. Everything became clear in 1962, when the American Mariner 2 from a distance of 35,000 km measured the brightness temperature of Venus (more than 400 ° C) and discovered the so-called darkening to the edge of the planet's disk (due to the greater thickness of the atmosphere at the edges). And this meant that most likely the temperature is associated with the surface of the planet.

The main data on the surface of Venus were obtained by the Magellan spacecraft from 1990 to 1994. This made it possible to create a map of the planet and make some assumptions about its internal structure and evolution. Earlier, the northern hemisphere of the planet was photographed by the Soviet stations Venera-15 and Venera-16.

The first space swallows

Actually, almost all information about the atmosphere, surface and internal structure of Venus was obtained using spacecraft. The first two attempts to explore Venus were made by the Soviet Union, even before the flight of Yuri Gagarin. On February 4, 1961, a 645-kilogram Venusian probe, landed on an almost six-ton ​​orbital platform, went into space from Tyuratam. The tandem went into low Earth orbit, from where the probe was supposed to go to Venus and crash into its surface. However, the probe's engines did not work, and on February 26, it, along with the platform, burned up in the earth's atmosphere. And on February 12, the Venera-1 automatic station was launched from Tyuratam. In all likelihood, in May 1962, it passed a hundred thousand kilometers from the target planet and turned into a man-made satellite of the Sun. However, communication with it disappeared a week after launch, when the station moved away from the Earth by 1.5 million kilometers. In the summer of 1962, two more unsuccessful launches followed, an American and a Soviet one. The fifth unit was the American Mariner 2, the one that buried the hypothesis of the Venusian seas.

In the early 1960s, all space programs, including lunar and planetary research, were carried out at OKB-1 under the leadership of Sergei Pavlovich Korolev. But the first launches of automatic interplanetary stations were not successful: there was too little experience in designing spacecraft. In 1965, Venera-2, a flyby vehicle, and Venera-3, an atmospheric probe, were launched, which was supposed to "stick" into the surface of the planet. The devices flew towards the Sun, the intensity of solar radiation grew as they approached the target, and during the flight the electronics failed. The devices reached Venus, but did not transmit any data. Nevertheless, this fact in itself was very significant - it was necessary to calculate the trajectory with the utmost accuracy in order for the device to make a rendezvous with the planet.

The upper boundary of the air layer of Venus lies at an altitude of only 250 km. The pressure at the surface of the planet is 92 atm - as at sea depths of 910 m. Carbon dioxide and water vapor create the strongest greenhouse effect, due to which the surface warms up to 467 ° C, despite the fact that sulfur clouds reflect ¾ of the sun's light. With this combination of temperature and pressure, both carbon dioxide and nitrogen are in a state of supercritical fluid. Therefore, strictly speaking, there is no gas at the surface of Venus at all.

In 1965, it was decided to divide the space programs into areas. Korolev continued to work on manned programs - orbital and lunar, and the unmanned lunar-planet theme, at the initiative of Keldysh and Korolev, was transferred to the OKB. S.A. Lavochkin, which at that time was headed by Georgy Nikolaevich Babakin. All technical documentation transferred from OKB-1 was subjected to the strictest revision, shortcomings were found, a number of systems were redesigned. The results were not long in coming - the very first launch of the E6 lunar program, made in mid-1966, led to the success of Luna-9, with a soft landing, with open petals, with a very original idea to shift the center of gravity for greater stability (device called "Roly-Vstanka"). The first panoramas of the Moon were obtained, the mechanical properties of the soil were studied, then the first artificial satellite of the Moon, Luna-10, was launched, followed by a whole series of successful launches.

Under the clouds

However, scientists were interested not only in the Moon, but also in Venus. But here a problem arose. If at least some assumptions could be made about temperature from previously obtained data, then no conclusions could be drawn about pressure. The range of possible pressure values, according to various estimates, ranged from 0.5 atm to several hundred, the depth of the atmosphere was unknown. Babakin discussed this issue for a long time with Keldysh and the leadership of the Space Research Institute (IKI). In the end, Babakin made a strong-willed design decision: "We will calculate the descent vehicle for 15 atm!" On October 18, 1967, the descent vehicle of the Venera-4 station began its parachute descent. Immediately after the antenna was opened, the radio altimeter gave a mark of 26 km (later it turned out that the real height at that moment was about 60 km). During the parachute descent, the device measured the pressure and temperature of the atmosphere, and also analyzed its composition. Upon reaching a pressure of 18 atm and a temperature of 260 °C, the apparatus was crushed, which was erroneously interpreted as the moment of landing (the actual height was about 28 km). The error of the radio altimeter was quickly found out, it was very annoying, but this mission made it possible to estimate the temperature and pressure on the surface - about 100 atm and 450 ° C. The chemical composition of the atmosphere was also specified.

The atmospheric probes "Venera-5" and "Venera-6", designed for a pressure of 25 atm, in 1969 confirmed and refined data on the composition and parameters of the Venusian atmosphere. Based on these data, the next station, Venera-7, was designed. Despite the fact that the telemetry switch failed during landing, and the parachute system worked abnormally, the device made the first soft landing on the night side of the planet and for the first time transmitted accurate data on pressure and temperature on the surface. And in 1972, after the death of Babakin, Venera-8 was launched. All systems worked absolutely flawlessly. The device made a soft landing on the surface of the planet, and for the first time on the day side, near the terminator. For the first time, data on the nature of the surface rocks became known, and this was a very major achievement. Venera-8 also measured the illumination for the first time: it turned out that even on the day side of the planet twilight reigns due to the scattering of sunlight in clouds and a dense atmosphere.

Twenty years of soft landings

In 1975, two next-generation vehicles, Venera-9 and Venera-10, were launched. Each station consisted of an orbital module and a descent vehicle, which carried an expanded complex of scientific instruments compared to previous missions. The orbital modules became the first artificial satellites of Venus, and the descent vehicles made a soft landing and for the first time transmitted panoramas of the planet's surface, which, along with the measurement of the content of natural radioactive elements, made it possible to draw a conclusion about the type of surface rocks and get some ideas about the evolution of the planet. We also studied the cloud layer (the device descended through this layer on parachutes, which were then unhooked to accelerate the descent and reduce the heating of the device) and the absorption spectra of the atmosphere. It turned out that mostly red and orange ranges reach the surface, so the Venusian day is actually an orange twilight.

In 1978, the descent vehicles Venera-11 and Venera-12 landed on the planet, which also studied the electrical activity of the atmosphere, and in 1982 Venera-13 and Venera-14 transmitted the first color images the surface of the planet. Data on the elemental composition of surface rocks were also obtained for the first time, which required an extremely complex experiment - it was necessary to lower the pressure and temperature, and only after that put the soil on the measuring shelf (for this, the devices were equipped with a special lock). The Venera-13 descent vehicle worked on the surface for 127 minutes, although it was designed for only 32. And this is at temperatures above 450 ° C and pressures of about 90 atm! In the same 1978, two American stations were launched - the orbital Pioneer Venus, which began radar mapping of the planet, and Pioneer Venus Multiprobe, which "shot" four atmospheric probes to analyze the composition and parameters of the atmosphere.

Venus has no planetary magnetic field of deep origin, and all of its extremely weak magnetism is generated by the interaction between the ionosphere and the solar wind.

"Venera-15" and "Venera-16" in 1983, using radar, mapped the northern hemisphere of the planet from orbit, which made it possible to assess the structure (morphology) of the surface. Later, the American satellite Magellan, launched in 1989, carried out global mapping of the planet for several years. And finally, the Soviet Venusian space program was completed in 1985 by two landing spacecraft Vega-1 and Vega-2 with a similar scientific load. They also launched balloons with scientific instruments that drifted in the atmosphere of Venus at an altitude of 50-60 km.

Venus became the real pride of the Soviet planetary program. Most of the data on this planet was obtained with the help of Soviet interplanetary stations, and these data are unique. The designers took very seriously the development of landers that were able to continue working in such extreme conditions for the time necessary to complete the scientific task.

In total, over the course of 45 years - from 1961 to 2005 - 37 attempts were made to send spacecraft to Venus. 19 of them were successful, 18 were unsuccessful. Another six automatic stations - the American Mariner 10, Galileo, Cassini and Messenger - one or two times passed by Venus on the way to their goals (respectively, to Mercury, Jupiter, Saturn and again to Mercury) and transmitted a lot of valuable information to Earth.

The political incorrectness of the past centuries is most clearly manifested in the names of the planets walking around the earth's sky. Almost all of them bear the names of the gods of the Roman pantheon. Only the second planet from the Sun became the namesake of the goddess, who initially played a very modest role as the patroness of gardens. Venus turned into a symbol of beauty and love later, when she (largely for political reasons) was identified with the Greek Aphrodite, the mother of the mythical founder of Rome, Aeneas. True, quite recently a tradition has emerged to name the geographical structures of the Venusian surface after real women and female literary characters (the only exceptions are the Maxwell Mountains and the high plateaus of Alpha and Beta).

The last, 670-kilogram European ship Venus Express, was launched into space on November 9, 2005 by the Russian Soyuz-Fregat rocket system from the Tyuratam cosmodrome. After 153 days of travel, he approached Venus and on May 6, 2006 entered a stable polar orbit with a minimum distance of 250 km from the planet and a maximum of 66,000 km. From there, he studies Venus and its atmosphere with his instruments (mostly various spectrometers). “Unfortunately, one of the instruments, the planetary Fourier spectrometer, failed,” says Lyudmila Zasova, head of the planetary spectroscopy laboratory of the Department of Physics of Planets and Small Bodies of the Solar System, IKI RAS. “But its tasks are partially covered by the VIRTIS mapping spectrometer, and with the help of other instruments, Venus Express has already received a lot of extremely interesting data about the planet’s atmosphere. Some things were a real surprise for us - for example, the presence of hydroxyl ions. But there are still many mysteries. For example, we still do not know what substance absorbs 50% of the solar ultraviolet in the range of 0.32-0.45 microns at altitudes of 58-68 km.”

What is inside and outside

Eighty percent of the Venusian surface is flat and hilly plains of volcanic origin. Most of the remainder falls on four gigantic mountain ranges - the Land of Aphrodite, the Land of Ishtar and the already mentioned regions of Alpha and Beta. The main surface material is basaltic lava. About a thousand impact craters with a diameter of three to three hundred kilometers have been discovered there. The absence of smaller craters is easily explained by the fact that meteorites capable of leaving them lose speed in the atmosphere or simply burn up. Venus is replete with volcanoes, but it is not yet known whether active volcanic activity has ceased there, and this is essential for understanding the evolution of the planet. In addition, despite the data from the Magellan satellite, scientists still have a poor understanding of the geology of Venus. And geology is the key to understanding the internal structure and evolutionary processes.

Until the 1950s, the hypothesis of warm Venusian oceans, which is full of not only aquatic plants, but also animals, was in a special fashion. Now we know that even the most terrible deserts of the Earth, compared with the waterless stony Venusian hell, look like fertile oases. There are no blue-deciduous trees on Venus, or even anything like extreme terrestrial archaebacteria that have broken all records in terms of survival in an unfriendly environment. And the sun there is not more golden than the earth. On the contrary, its rays almost do not penetrate dense clouds of sulfur dioxide and aerosol sulfuric acid, circulating at an altitude of 45–70 km and reliably hiding the planet from terrestrial telescopes. In a word, hellish place.

Whether Venus has a solid core or a liquid one is not yet known for sure. In any case, there are no circular flows of electrically conductive matter in it, since otherwise the planet would have a stable earth-like magnetic field. “The magnetic passivity of Venus has not yet found a generally accepted interpretation,” Sean Solomon, director of the department of terrestrial magnetism at the Carnegie Institution in Washington, told Popular Mechanics. - The presence of a magnetic field near the Earth is most likely due to the gradual solidification of the still liquid outer core of our planet. This process releases thermal energy, which provides convective motions of nuclear matter, which make possible the emergence of a magnetic field. Obviously, this does not happen on Venus. Why is not yet clear. According to the most plausible hypothesis, the Venusian core has not yet begun to solidify and therefore convective jets are not born there, twisting due to the rotation of the planet and generating a magnetic field. Otherwise, such a field still should have arisen, although in magnitude it would be much inferior to the earth's one, since Venus rotates around its axis much more slowly. Theoretically, it can be assumed that the Venusian core has already cooled below the point of crystallization of its substance. This is possible, but unlikely. To do this, one would have to assume that the core of Venus consists of almost pure iron and is practically devoid of light impurities that reduce the phase transition temperature. It is difficult to see how Venus could acquire such a core during its formation. Therefore, the first hypothesis seems to be preferable.

Why is Venus so hot? The main model for heating the surface of Venus is considered to be the greenhouse effect. Calculations show that when the Earth moves 10 million kilometers closer to the Sun, the greenhouse effect gets out of control and irreversible heating begins. This is a very delicate balance, which is why climate scientists are worried. So far, no one knows the limits of compensatory processes beyond which positive feedback begins to act. There are models in which, during the first tens of millions of years after its formation, Venus was different - it had oceans, almost the same as on Earth. In particular, this is confirmed by the fact that the atmosphere of Venus is enriched with deuterium. “More accurate measurements of the isotopic composition of the atmosphere will allow us to make assumptions about why Venus took a different path than Earth and Mars,” says Lyudmila Zasova. “Perhaps this will be found out by the Russian Venera-D mission, which is planned to be launched after 2015.” The interplanetary station will consist of an orbital module, a long-lived descent vehicle and atmospheric balloon probes.

Scientists have high hopes for the next flights to Venus. For now, this planet raises many more questions than it answers.

Instruction

A star, unlike other celestial bodies, is a concentrated accumulation of gases and many chemical elements. This object is constantly in the development stage and radiates a huge amount of heat and energy, due to which the planets exist in the system of this star.

The sun or any other in the center of a single galaxy is a key link in the construction of the solar or other system. All planets and bodies revolve around their orbits and around the star.

An asteroid, unlike a star, is a relatively small body with a small mass and volume. It consists in most cases of one or more mineral or metallic rocks, and therefore has most often an irregular shape. Asteroids, like the rest of the planets in the galaxy, revolve around a star.

In some cases, when the gravitational force of the nearest planet is strong, the asteroid may deviate from its trajectory and onto the surface of the planet. The protective field of the Earth in the form of the atmosphere tends to weaken the rate of fall, and the force of friction against the air burns the approaching celestial body. In isolated cases, fragments of celestial bodies reach the surface of the Earth. This phenomenon is of general interest, as in the case of the Chelyabinsk meteorite.

Asteroids for a long time did not differ from stars, even the name itself comes from the Latin "like a star." Back in 2005, many asteroids were considered minor planets, but in 2006 it was decided to consider celestial bodies with a diameter of more than 30 meters, but less than 900 kilometers, as asteroids. Size and composition are the main stars and asteroids. However, unlike an asteroid, which can be conditionally called a body, a cleavage of a planet, stars evolve, they can grow and collapse.

The visual difference between an asteroid and a star is in the brightness of the glow: you cannot look with your naked eyes at the sun closest to us, while a passing asteroid can be an object of observation.

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Advice 4: How to distinguish a star from a planet with the naked eye

Space has attracted the inquisitive gaze of people since time immemorial. Over the past millennia, a lot of information has been accumulated about stars, planets, black holes, galactic clusters and other cosmic realities. Of course, for a more detailed study of space, one cannot do without special equipment. However, some points can be learned to capture with the naked eye.

Stars are held together by their own gravity and internal pressure.

Let's make a reservation right away: only the planets of our solar system can be fixed with the naked eye.

Planet, star. Differences

Both the planet and the star are characterized by luminescence, by which, in fact, they can be seen from the Earth. However, a star is a self-luminous object. While the planet glows due to the light reflected from the stars. Therefore, the radiation of the planets is many times weaker than the stellar radiation. This is especially noticeable on a frosty night or. The radiance of the stars is much more intense (especially those closer to the horizon). The glow of the planets is muted or even indistinct.

Venus and Jupiter, by the way, are an exception to the rule. They can be easily recognized by their characteristic glow, which is much brighter than some distant stars. Also, pay attention to the hue of the radiation. Venus is distinguished by its cold bluish-white glow. Mars is reddish, Saturn is yellow, and Jupiter is yellow with a touch of white.

Another distinguishing feature is the nature of the light emission. For stars, the twinkling caused by the fluctuation of the air is more characteristic. Even in the lenses of powerful telescopes, stars are represented by blinking dots. The planets, in turn, shine evenly, albeit more dimly.

The most effective method to recognize a celestial body is to observe the object. It is recommended to observe the sky for several days. You can even graphically fix the location of the main bodies and compare the results day by day. The bottom line is that the stars are fixed in relation to each other. The only thing that will change for them is the time of their appearance in the sky. The planets, on the other hand, are unstable. They move along unthinkable trajectories relative to the stars, sometimes changing their route to the opposite one.

Space Tricks

There are certain nuances that you need to know when observing the sky. Venus, for example, invariably appears in the East, just before sunrise. Visually, it resembles a bright spot during this period. If you look at night in the right direction - you can see Jupiter.

It will not be superfluous to familiarize yourself with the astrological calendar. With it, you can find out in advance which planets will be in the visibility zone at certain intervals.

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• HOW TO DIFFERENTIATE A PLANET FROM A STAR?

For thousands of years, people have peered into the starry sky. Whether it was the creation of legends and myths, observing the change of seasons, or navigating the expanses of the oceans, the celestial sphere has been one of the most important helpers of mankind throughout its history.

In this compilation, we take a look at 25 of the brightest space objects that you can see (depending on the light pollution in your area) just by looking up at the sky.

The objects in this list are sorted by their degree of brightness to the average observer from Earth, a unit of measurement known as apparent magnitude.

The Carina Nebula is home to the Milky Way's brightest star.

We'll start our compilation of "The 25 Brightest Space Objects Visible to the Naked Eye" with the only nebula on this list: the Carina Nebulae.

The Carina Nebula is an interstellar collection of cosmic dust and ionized gas. It is especially notable for the fact that it contains the brightest star in the Milky Way - WR25.

Although this star is as bright as 6,300,000 of our Suns, it did not make it into the Top 25 presented because of its distance from us - almost seven and a half thousand light years. For comparison, the Sun is separated from the Earth by a distance of only 0.000016 light years.

Spica Star

Spica is a double star in the constellation Virgo.

In the night sky, we can see other galaxies and nebulae - such as our own Milky Way, the Orion Nebulae, the Pleiades, and the Andromeda Galaxy - but, in terms of apparent magnitude, they are paler than the other celestial bodies on our list.

Therefore, the second place is occupied by the star Spica - the alpha of the constellation Virgo. Spica is technically two stars so close that together they form one egg-shaped star.

Star Antares - "Heart of the Scorpion"

The next chosen one is six hundred light years away from Earth and is known as the "Heart of Scorpio", as it is the brightest star in this constellation.

Antares is best observed around May 31, when it is directly opposite the Sun, appearing at dusk and disappearing at dawn.

Alpha star of the constellation Taurus

The star Aldebaran (not to be confused with Alderaan - the home planet of Princess Leia from Star Wars) is the alpha of the constellation Taurus. Aldebaran means "follower" in Arabic.

Aldebaran is easy to spot in the night sky - just find Orion's Belt and count three stars clockwise (or vice versa if you're in the Southern Hemisphere) to the next brightest star.

Humanity will learn more about Aldebaran when the Pioneer 10 probe passes by this star in two million years. Oh yeah. Let's not wait.

Alpha Southern Cross (Acrux)

Triple star system in the constellation Crux

The Southern Cross is one of the most recognizable figures in the night sky, also known as the constellation Crux. Its brightest star, its alpha - Akruks - was placed on their flags by five states: Australia, Papua New Guinea, Samoa, New Zealand and Brazil.

In fact, Akrux is not a single star, but a star system of three components. Judging by the mass and brightness, two of its stars will soon turn into supernovae.

To find Akrux, look to the "bottom" of the Southern Cross.

Altair

Altair - one of the peaks of the Great Summer Triangle

The star Altair is the second brightest peak of the Great Summer Triangle. Of the vertices of the Summer Triangle, Altair is also the closest star to the Earth and the alpha of the constellation Aquila.

The neighboring peak of the Triangle - the star Deneb, alpha Lyra - seems to us paler than Altair, but only because it is 214 times farther from us. In terms of absolute magnitude, Deneb is seven thousand times brighter than Altair.

Beta Centauri (Agena, Hadar)

Beta Centauri - a faithful assistant to navigators before the invention of the compass

The triple star system Beta of the constellation Centaurus has historically been one of the most important and brightest objects in the night sky.

Before the invention of the compass, navigators determined the location of the south, connecting Beta Centauri and Acrux with an imaginary line - the reference points of the Southern Cross - an analogue of the Polar Star in the other hemisphere. Both the Southern Cross and the Polar Star have played the role of the main and reliable landmark in navigation since ancient times.

Betelgeuse is our chance to see a supernova explosion for the first time in a thousand years

The star Betelgeuse is so huge that if placed in the place of our Sun, it will swallow the Earth with Venus and Mercury, and even Mars. This massive supergiant stands out among the objects on our list as the most variable apparent magnitude. In addition, it can be observed almost everywhere from autumn to spring.

And Betelgeuse is also a chance for us earthlings to see a supernova explosion for the first time since 1054.

Finding Betelgeuse in the sky is easy. Look at the bright red star perpendicular to Orion's Belt.

Achernar

Alpha Eridani - blue and hot

Achernar is the bluest and hottest celestial body that we can observe with the naked eye.

Interestingly, due to the peculiarities of the orbital trajectory, Achernar escaped the attention of most of our predecessors, and even from the ancient Egyptian astronomers.

And the extremely high rotation speed gives Achernar the least spherical shape among the bodies of the Milky Way.

Top of the Great Winter Triangle

Procyon is the second brightest star in the Great Winter Triangle. In the sky, it looks reddish, especially at the end of winter.

Procyon appears in the cultures of many peoples, from the ancient Babylonians and Hawaiians to the Brazilian ethnic group Kalapalo.

The Eskimos call Procyon Sikuliarsiujuittuq - after the fat man from the legend who stole from his relatives because he was too heavy to hunt on the ice. Other hunters convinced him to go to the newly formed ice, and the fat man drowned. The Eskimos associated the color of his blood with Procyon.

Star Rigel

A blue-white supergiant in the constellation Orion

Rigel is the brightest star in the zodiac constellation Orion. It is located opposite Orion's Belt diagonally from Betelgeuse.

Rigel is the farthest star from Earth in this compilation, we are separated by 863 light years. Rigel is also notable for its variable apparent magnitude, which is caused by its pulsations - the result of thermonuclear reactions of hydrogen fusion.

Chapel

Alpha constellation Auriga

Capella means "little goat" in Latin. It sounds incomprehensible to modern people, but the Greeks, and after them the Romans, revered this star very much, because they associated it with the goat that nursed the god Zeus.

Capella has an apparent magnitude of 0.07 and is the third brightest star in the Northern Hemisphere. Inhabitants of latitudes north of 44 ° N can see the Chapel both day and night.

Vega is the alpha of the constellation Lyra

Vega is one of the most important stars in the sky, some even consider it the second most important after the Sun.

Located just 25 light-years from Earth, Vega was our North Star 14,000 years ago. And it will regain that status around 13727, when changes in its orbit will once again make it brighter than the current Polaris.

Vega is also known as the first star after the Sun to be captured on film.

Arcturus - alpha of Bootes

The star Arcturus is the brightest star in the northern celestial hemisphere.

Probably, it was this orange giant that helped the Polynesians so successfully cross the Pacific Ocean.

To find Arcturus in the night sky, follow the handle of the Big Dipper to the first bright star.

Magellan's Navigator

Alpha Centauri is a binary star system with Beta Centauri.

In absolute magnitude, it is not much brighter than our Sun and is closest to the solar system (only 4.37 light years).

In addition, it is one of the reference points of the Southern Cross, which helped Magellan and other navigators plot a course across the ocean in the Southern Hemisphere.

Many astronomers believe that there is a planet in the orbit of this star system, and not even one.

Star Canopus

Alpha constellation Carina

Canopus is the second brightest star in the night sky, and in the time of the dinosaurs, it would have led the list of the brightest stars by apparent magnitude.

While another star now takes precedence, whose name is immortalized in the name of Harry Potter's godfather, Canopus will return to the top of the list in about 480,000 years, when it will once again become the brightest star in the night sky.

Canopus appears white to the naked eye, but takes on a yellowish tint when viewed through a telescope.

Sirius is the brightest star in the earth's sky

The brightest star in the night sky, Sirius, also called the "Dog Star", because it is part of that part of the constellation, which is called the "dog of Orion".

The phrase "the days of the dog are over" (as, for example, in the song of the same name by Florence + The Machine) comes from Sirius.

According to the location of Sirius in the sky, the ancient Greeks determined when the “days of the dog” began - the hottest period of the summer season.

Saturn is the palest of the visible planets

The first and palest of the planets of the solar system visible to the naked eye is Saturn. At the same time, Saturn is one of the most exciting cosmic bodies to observe through a telescope.

Even small telescopes (with a minimum magnification of 30x) are able to make out Saturn's famous rings - mostly made up of fragments of ice and rock.

And the largest moon of Saturn - Titan - can be seen even with strong binoculars.

Mercury is the seventh brightest object in the sky visible to the naked eye.

Since Mercury revolves around the Sun within the Earth's orbit, it is visible from the surface of our planet only in the mornings and evenings, and never in the middle of the night.

Like our moon, Mercury has a series of phases that can be observed with a telescope.

Earth's Bright Neighbor

Mars has been the focus of professional and amateur astronomers for millennia. Easily visible in the night sky due to its characteristic hue, the Red Planet has an apparent magnitude of -2.91. Best of all, Mars was visible from July to September 2003, especially in August, when Mars was brighter for earthlings than in the previous 60 thousand years. Jupiter

The largest planet in the solar system, Jupiter is an easy target to find and observe with the naked eye.

And with a simple telescope, you can make out the famous cloud belts that envelop the surface of Jupiter, and maybe even its four largest moons.

If you choose the right time and a strong telescope, you will be able to admire the Great Red Spot of Jupiter.

Venus is the brightest of the planets visible to the naked eye.

The brightest planet that we can see with the naked eye, Venus has played an important role in human culture for thousands of years.

Sung by poets as the morning and evening star, Venus appears after sunset, overtaking the Earth in its annual rotation cycle, and before dawn, passing by the Earth.

Venus is so bright that it can be seen even at noon.

International Space Station

The only man-made visible space object

The only man-made object on our list, the International Space Station, circles the Earth 15 times a day, creating many opportunities for observation, although it is sometimes confused with a fast-moving aircraft.

To find out when the ISS will pass exactly over your head, visit NASA's dedicated resource spotthestation.nasa.gov.

Only the sun is brighter

Our beloved Moon is the most recognizable and largest object in the night sky visible to the naked eye. Sometimes visible even in daylight, the Moon always shows us only one side of itself, as it rotates in sync with the Earth.

During his tenure, George W. Bush proposed a project to create a lunar base by 2024, but since then NASA's focus has shifted to sending a man into orbit around Mars in 2035.

Sunrise on Maui, Hawaii

Is it any wonder that the life-giving star leads the list of the brightest space objects.

But, although you can look at the sun with your naked eye, try to avoid it: maybe a few seconds of direct observation will not blind you, but a few hours will certainly do it.

The star charts have been revealed. The most notable stars of the night sky acquired their names and stories, experienced astrologers tested their knowledge, and readers far from astrophysics discovered a new unknown world full of shining cosmic stars.

Parallel and pocket universes have their own star charts, but in this one the laws of quantum mechanics apply - observers change the observed - and each of our glance upwards changes something - invisibly and irreversibly.

morning Star

The only planet in the solar system, named after the goddess of love - Venus, is the brightest planet inhabiting the earth's firmament. Venus is closest to our planet, and since its surface is covered with dense clouds, it reflects about 76% of the sunlight. The peak of Venus' brightness in the night sky can be observed shortly before sunrise or some time after sunset, so it is sometimes called the Morning Star or Evening Star.

Venus is the closest planet to Earth, in brightness it far exceeds the light of the brightest stars, while Venus, unlike twinkling stars, glows with even white light. Ancient scientists believed that morning and evening Venus are different stars. Venus is the third brightest object in the sky, after the Sun and Moon. Even with a weak telescope, you can see the different phases of the visibility of the planet's disk: in 1610, this was first noted by Galileo.

Atmosphere of Venus

The sizes of the Earth and Venus are almost identical, and they are also the only solid circumsolar planets with a dense atmosphere. These and other facts, until the middle of the 20th century, gave rise to high expectations of astronomers regarding the habitability of the nearest planet.

But it turned out that there is no life on this bright and beautiful planet, because the atmosphere of Venus consists of poisonous carbon dioxide and is very dense, which allows it to retain heat, and makes it very hot. Also, it would seem that there is a small difference in distances of 45 million km. Earth and Venus from the Sun became fatal for the existence of any life on this celestial body.

Interesting fact

An interesting fact is that the Earth's sister Venus is the only planet that rotates around its axis in the opposite direction. It completes this turn in 243 Earth days. The slow and reverse rotation has led to the fact that on Venus the Sun rises and sets only 2 times per Earth year. Here it is - the brightest planet, which is easier to find in the sky than any other.