At the North Pole
272.76°
(464°C)
~3.5% Nitrogen
0.015% Sulfur dioxide
0.007% Argon
0.002% Water vapor
0.0017% Carbon monoxide
0.0012% Helium
0.0007% Neon
(traces) Carbon sulfide
(traces) Hydrogen chloride
(traces) Hydrogen fluoride
Venus- the second inner planet of the solar system with a period of revolution of 224.7 Earth days. The planet got its name from Venus, the goddess of love from the Roman pantheon. Her astronomical symbol is a stylized version of a lady's mirror, an attribute of the goddess of love and beauty. Venus is the third brightest object in the Earth's sky after the Sun and Moon and reaches an apparent magnitude of −4.6. Since Venus is closer to the Sun than the Earth, it never seems to be too far from the Sun: the maximum angular distance between it and the Sun is 47.8°. Venus reaches its maximum brightness shortly before sunrise or some time after sunset, which gave reason to call it also Evening Star or morning Star.
Venus is classified as an Earth-like planet and is sometimes referred to as "Earth's sister" because the two planets are similar in size, gravity, and composition. However, the conditions on the two planets are very different. The surface of Venus is hidden by extremely dense clouds of sulfuric acid clouds with high reflective characteristics, which makes it impossible to see the surface in visible light (but its atmosphere is transparent to radio waves, with the help of which the planet's relief was subsequently studied). Disputes about what is under the thick clouds of Venus continued until the twentieth century, when many of the secrets of Venus were not revealed by planetary science. Venus has the densest atmosphere of any Earth-like planet, consisting mainly of carbon dioxide. This is explained by the fact that on Venus there is no cycle of carbon and organic life that could process it into biomass.
In ancient times, Venus is believed to have warmed up so much that the Earth-like oceans that it is believed to have had completely evaporated, leaving behind a desert landscape with many plate-like rocks. One hypothesis suggests that due to the weakness of the magnetic field, water vapor rose so high above the surface that it was carried away by the solar wind into interplanetary space.
Basic information
The average distance of Venus from the Sun is 108 million km (0.723 AU). Its orbit is very close to circular - the eccentricity is only 0.0068. The period of revolution around the Sun is 224.7 days; average orbital speed - 35 km / s. The inclination of the orbit to the plane of the ecliptic is 3.4°.
Comparative sizes of Mercury, Venus, Earth and Mars
Venus rotates around its axis, deviated by 2 ° from the perpendicular to the plane of the orbit, from east to west, that is, in the direction opposite to the direction of rotation of most planets. One revolution around the axis takes 243.02 days. The combination of these movements gives the value of the solar day on the planet 116.8 Earth days. Interestingly, Venus makes one revolution around its axis with respect to the Earth in 146 days, and the synodic period is 584 days, that is, exactly four times longer. As a result, at each inferior conjunction, Venus faces the Earth with the same side. It is not yet known whether this is a coincidence, or whether the gravitational attraction of the Earth and Venus is acting here.
Venus is quite close to Earth in size. The radius of the planet is 6051.8 km (95% of the earth), the mass is 4.87 × 10 24 kg (81.5% of the earth), the average density is 5.24 g / cm³. The free fall acceleration is 8.87 m / s², the second space velocity is 10.46 km / s.
Atmosphere
The wind, which is very weak near the surface of the planet (no more than 1 m/s), increases to 150-300 m/s near the equator at an altitude of over 50 km. Observations from automatic space stations were found in the atmosphere of a thunderstorm.
Surface and internal structure
The internal structure of Venus
Exploration of the surface of Venus became possible with the development of radar techniques. The most detailed map was made by the American Magellan apparatus, which photographed 98% of the planet's surface. Mapping has revealed vast uplands on Venus. The largest of them are the Land of Ishtar and the Land of Aphrodite, comparable in size to the earth's continents. Numerous craters have also been identified on the surface of the planet. They probably formed when Venus's atmosphere was less dense. A significant part of the planet's surface is geologically young (about 500 million years). 90% of the planet's surface is covered with solidified basaltic lava.
Several models of the internal structure of Venus have been proposed. According to the most realistic of them, there are three shells on Venus. The first - the crust - is about 16 km thick. Next - the mantle, a silicate shell, extending to a depth of about 3300 km to the border with the iron core, the mass of which is about a quarter of the entire mass of the planet. Since there is no own magnetic field of the planet, it should be assumed that there is no movement of charged particles in the iron core - an electric current that causes a magnetic field, therefore, there is no movement of matter in the core, that is, it is in a solid state. The density in the center of the planet reaches 14 g/cm³.
Interestingly, all the details of the relief of Venus bear female names, with the exception of the highest mountain range of the planet, located on Ishtar Earth near the Lakshmi plateau and named after James Maxwell.
Relief
Craters on the surface of Venus
An image of the surface of Venus based on radar data.
Impact craters are a rare feature of the Venusian landscape. There are only about 1,000 craters on the entire planet. The picture shows two craters with diameters of about 40 - 50 km. The inner area is filled with lava. The "petals" around the craters are patches covered with crushed rock thrown out during the explosion during the formation of the crater.
Observation of Venus
View from Earth
Venus is easily recognizable, as it far exceeds the brilliance of the brightest of the stars in brilliance. 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.
With a telescope, even a small one, one can easily see and observe the change in the apparent phase of the planet's disk. It was first observed in 1610 by Galileo.
Venus next to the Sun, covered by the Moon. Frame of the apparatus Clementine
Passage on the disk of the Sun
Venus on the disk of the Sun
Venus in front of the Sun. Video
Since Venus is the inner planet of the solar system in relation to the Earth, its inhabitant can observe the passage of Venus across the disk of the Sun, when from the Earth through a telescope this planet appears as a small black disk against the background of a huge luminary. However, this astronomical phenomenon is one of the rarest that can be observed from the Earth's surface. Over the course of about two and a half centuries, there are four passages - two in December and two in June. The next one will take place on June 6, 2012.
For the first time observed the passage of Venus across the disk of the Sun on December 4, 1639, the English astronomer Jeremiah Horrocks (-) He also predicted this phenomenon.
Of particular interest to science were the observations of the “phenomenon of Venus on the Sun”, which were made by M. V. Lomonosov on June 6, 1761. This cosmic phenomenon was also pre-calculated and eagerly anticipated by astronomers around the world. Its study was required to determine the parallax, which made it possible to clarify the distance from the Earth to the Sun (according to the method developed by the English astronomer E. Halley), which required the organization of observations from different geographical points on the surface of the globe - the joint efforts of scientists from many countries.
Similar visual studies were carried out at 40 points with the participation of 112 people. On the territory of Russia, they were organized by M.V. Lomonosov, who on March 27 addressed the Senate with a report substantiating the need for equipment for astronomical expeditions to Siberia for this purpose, petitioned for the allocation of funds for this expensive event, he compiled guides for observers, etc. The result of his efforts was the direction of the expedition of N. I. Popov to Irkutsk and S. Ya Rumovsky to Selenginsk. It also cost him considerable efforts to organize observations in St. Petersburg, at the Academic Observatory, with the participation of AD Krasilnikov and NG Kurganov. Their task was to observe the contacts of Venus and the Sun - visual contact of the edges of their disks. M. V. Lomonosov, who was most interested in the physical side of the phenomenon, conducting independent observations at his home observatory, discovered a light rim around Venus.
This passage was observed all over the world, but only M.V. Lomonosov drew attention to the fact that when Venus came into contact with the disk of the Sun, a “shine as thin as hair” arose around the planet. The same bright halo was observed during the descent of Venus from the solar disk.
MV Lomonosov gave a correct scientific explanation for this phenomenon, considering it to be the result of the refraction of solar rays in the atmosphere of Venus. “The planet Venus,” he wrote, “is surrounded by a noble airy atmosphere, such (if only not more) than is poured around our globe.” So for the first time in the history of astronomy, a hundred years before the discovery of spectral analysis, the physical study of the planets began. At that time, almost nothing was known about the planets of the solar system. Therefore, the presence of an atmosphere on Venus was considered by M. V. Lomonosov as indisputable evidence of the similarity of the planets and, in particular, the similarity between Venus and the Earth. The effect was seen by many observers: Chappe D'Oteroche, S. Ya. Rumovsky, L. V. Vargentin, T. O. Bergman, but only M. V. Lomonosov interpreted it correctly. In astronomy, this phenomenon of light scattering, the reflection of light rays during grazing incidence (for M. V. Lomonosov - “pimple”), received his name - “ The phenomenon of Lomonosov»
Of interest is the second effect observed by astronomers as the disk of Venus approaches or moves away from the outer edge of the solar disk. This phenomenon, also discovered by M.V. Lomonosov, was not satisfactorily interpreted, and, apparently, it should be regarded as a mirror image of the Sun by the planet’s atmosphere - it is especially large at small glancing angles, when Venus is near the Sun. The scientist describes it as follows:
Planetary exploration using spacecraft
Venus has been studied quite intensively with the help of spacecraft. The first spacecraft designed to study Venus was the Soviet Venera-1. After an attempt to reach Venus by this apparatus, launched on February 12, Soviet apparatuses of the Venera, Vega series, American Mariner, Pioneer-Venera-1, Pioneer-Venera-2, Magellan were sent to the planet. The spacecraft "Venera-9" and "Venera-10" transmitted to Earth the first photographs of the surface of Venus; in Venera-13 and Venera-14, color images were transmitted from the surface of Venus. However, the conditions on the surface of Venus are such that none of the spacecraft has worked on the planet for more than two hours. In 2016, Roscosmos plans to launch a more durable probe that will work on the surface of the planet for at least a day.
additional information
Satellite of Venus
Venus (like Mars and the Earth) has a quasi-satellite, asteroid 2002 VE68, orbiting the Sun in such a way that there is an orbital resonance between it and Venus, as a result of which it remains near the planet for many periods of revolution.
Terraforming Venus
Venus in various cultures
Venus in literature
- In Alexander Belyaev's novel Leap into Nothing, the heroes, a handful of capitalists, flee from the world proletarian revolution into space, land on Venus and settle there. The planet is presented in the novel roughly as the Earth in the Mesozoic era.
- In Boris Lyapunov's sci-fi essay "Nearest to the Sun", earthlings set foot on Venus and Mercury for the first time and study them.
- In Vladimir Vladko's novel The Argonauts of the Universe, a Soviet exploration expedition is sent to Venus.
- In Georgy Martynov's novel-trilogy "Stargazers", the second book - "Sister of the Earth" - is dedicated to the adventures of Soviet cosmonauts on Venus and acquaintance with its intelligent inhabitants.
- In the cycle of stories by Viktor Saparin: "Heavenly Kulu", "Return of the Roundheads" and "Disappearance of Loo", the astronauts who landed on the planet establish contact with the inhabitants of Venus.
- In Alexander Kazantsev's story "The Planet of Storms" (the novel "Grandchildren of Mars"), astronauts-researchers encounter the animal world and traces of intelligent life on Venus. Filmed by Pavel Klushantsev as "Planet of Storms".
- In the Strugatsky Brothers' novel The Country of Crimson Clouds, Venus was the second planet after Mars, which they are trying to colonize, and they send the Khius planetary ship with a crew of scouts to the area of deposits of radioactive substances called "Uranium Golconda".
- In Sever Gansovsky's story "Saving December", the last two observers of earthlings meet December, the animal on which the natural balance on Venus depended. The Decembers were considered completely exterminated and people are ready to die, but leave the December alive.
- The novel by Yevgeny Voiskunsky and Isai Lukodyanov "Splash of the Starry Seas" tells about reconnaissance cosmonauts, scientists, engineers who, in difficult conditions of space and human society, are colonizing Venus.
- In Alexander Shalimov's story Planet of the Mists, the expedition members sent on a laboratory ship to Venus are trying to solve the riddles of this planet.
- In the stories of Ray Bradbury, the climate of the planet is presented as extremely rainy (either it always rains, or it stops once every ten years)
- In Robert Heinlein's novels Between the Planets, The Martian Podkane, The Space Cadet, and The Logic of Empire, Venus is depicted as a gloomy swampy world, reminiscent of the Amazon valley during the rainy season. Venus is inhabited by intelligent inhabitants resembling seals or dragons.
- In Stanislav Lem's novel The Astronauts, earthlings find on Venus the remains of a dead civilization that was about to destroy life on Earth. Screened as "Silent Star".
- Francis Karsak's "Escape of the Earth", along with the main plot, describes the colonized Venus, the atmosphere of which has undergone physical and chemical processing, as a result of which the planet has become habitable for people.
- The science fiction novel Fury by Henry Kuttner tells of the terraforming of Venus by colonists from a dead Earth.
Literature
- Koronovsky N. N. Morphology of the surface of Venus // Soros Educational Journal.
- Burba G. A. Venus: Russian transcription of names // GEOKHI Laboratory for Comparative Planetology, May 2005.
see also
Links
- Pictures taken by Soviet spacecraft
Notes
- Williams, David R. Venus Fact Sheet. NASA (April 15, 2005). Retrieved October 12, 2007.
- Venus: Facts & Figures. NASA. Retrieved April 12, 2007.
- Space Topics: Compare the Planets: Mercury, Venus, Earth, The Moon, and Mars. planetary society. Retrieved April 12, 2007.
- Caught in the wind from the Sun. ESA (Venus Express) (2007-11-28). Retrieved July 12, 2008.
- college.ru
- RIA agency
- Venus had oceans and volcanoes in the past - scientists RIA News (2009-07-14).
- M. V. Lomonosov writes: “... Mr. Kurganov, by his calculation, found out that this memorable passage of Venus across the Sun, packs in May 1769, 23 days old calm, will happen, which, although it is doubtful to see in St. Petersburg, only many places near the local parallel, and especially lying further to the north, may be witnesses. For the beginning of the introduction will follow here at 10 o'clock in the afternoon, and the beginning at 3 o'clock in the afternoon; is likely to pass through the upper half of the Sun at a distance from its center close to 2/3 of the solar half-diameter. And since 1769, after a hundred and five years, this phenomenon apparently has again. the same October 29, 1769, the same passage of the planet Mercury across the Sun will be visible only in South America ”- M. V. Lomonosov“ The phenomenon of Venus on the Sun ... ”
- Mikhail Vasilievich Lomonosov. Selected works in 2 volumes. M.: Science. 1986
Venus in the sky at the beginning of 2014 - 16 photos.
The beautiful Evening Star is preparing to move into the morning sky: on January 11, there will be a lower conjunction of the planet with the Sun. Approaching in the sky with the luminary, Venus demonstrates phases, like that of the Moon. At the same time, its apparent dimensions increased to 1 arc minute.
Hundreds of photographs of Venus have appeared on the Internet, taken in various parts of the world. We have selected 16 images showing the phase of Venus, the elongation of its horns and other interesting and beautiful celestial phenomena with the participation of this planet.
Venus in the rays of the evening dawn on December 31, 2013. The planet is so bright that it leaves a distinct path on the water surface. Image taken in El Salvador, Central America. A photo: Sergio Emilio Montufar Codoner
The narrow crescent of Venus. As Venus and the Sun approach in our sky, the part of the planet facing us is less and less illuminated by the star, showing phases similar to those of the moon. In this image, the crescent of Venus is very narrow, yet bright enough to be visible against a still blue sky, behind a veil of light clouds. If the Moon, which is generally composed of rather dark rocks, reflects less than 10% of the sunlight falling on it, then the clouds of Venus are bright as snow. This explains its great brilliance even at the minimum phase. This picture was taken on January 4 in Romania with a 110mm refractor (100x magnification). A photo: Maximilian Teodorescu
Crescent of Venus a week before inferior conjunction. The image was taken with a Celestron C5 telescope fixed on an azimuth mount. Exposure was 1/250 second, ISO 400, camera Canon EOS T3. A photo: Steven Bellavia
Conjunction of the Moon and Venus in the evening sky on January 3. On the left, Venus and the Moon are captured in one frame (equipment FUJI HS20EXR, 364 mm), on the right - their more detailed, enlarged images obtained with a Canon 1100D, 1300 mm. The crescent of Venus is now about 30 times smaller than the crescent of the Moon, but the planet itself is almost 100 times farther from us than the Moon. A photo: Pal VARADI NAGY
New Year's crescent. Venus captured with a long telephoto lens from Quebec City, Canada on a chilly evening on December 30th. A photo: Jay Ouellet
Bright Venus illuminates the clouds over the Swiss Alps. A photo: Christoph Malin
Clouds and crescents: conjunction of the Moon and Venus on January 2, 2014. Photographer Christoph Malin took several shots of the compound, one of which appeared on January 2 on the authoritative website APOD (Astronomy Picture of the Day). A photo: Christoph Malin
In this picture, Venus hanging low above the horizon is captured along with an astronomical phenomenon unfamiliar to the vast majority of city dwellers - the zodiacal light. The zodiacal light is a faint cone-shaped glow that stretches along the ecliptic (in the picture, the cone is stretched upward above Venus). The glow is due to the scattering of sunlight on interplanetary dust that has accumulated in the plane of the orbits of the planets. A photo: Sergio Montufar
An airplane flying in front of a Venusian sickle. The picture was taken on January 1 in Utah (USA). A photo: Barry Glazier
Venus on the background of iridescent clouds. The picture was taken on the afternoon of January 5 in the Netherlands. A photo: Jan Koeman
Venus appeared as a giant C in the evening sky on January 4 to the author of this image, Mariano Ribas from Buenos Aires, when he pointed his refractor telescope at it. A photo: Mariano Ribas
Elongated "horns" of Venus. Sunlight, refracted in the dense atmosphere of the planet, penetrates far beyond the horizon. A photo: Shahrin Ahmed
As Venus approaches the Sun in our sky, its crescent becomes thinner. In this image, only a little over 1% of the surface of Venus facing us is illuminated by a star. A photo: Shahrin Ahmed
A few minutes after sunset, Venus shines brightly in the rays of the evening dawn. This picture was taken in San Francisco; the planet glitters above the spreading fog and above the eucalyptus trees. A photo: fksr
Melting crescent of Venus. A photo: Shahrin Ahmed
Finding her in the sky is very easy. Everyone happened to notice how sometimes in the evening in a still very bright sky the “evening star” lights up. As the dawn fades, Venus becomes brighter and brighter, and when it gets completely dark and other stars appear, she stands out sharply among them. But Venus does not shine for long. An hour or two passes, and she comes in. In the middle of the night, she never appears, but there is a time when she can be seen in the morning, before dawn, in the role of the “morning star”. It will already be completely dawn, all the other stars will long disappear, and Venus still shines and shines against the bright background of the morning dawn.
People have known Venus since time immemorial. Many legends and beliefs were associated with it. In ancient times, they thought that these were two different luminaries: one appears in the evenings, the other in the mornings. Then they guessed that it was the same luminary, the beauty of the sky, the "evening and morning star" - Venus. "Evening Star" has been sung by poets and composers more than once, described in the works of great writers, depicted in the paintings of famous artists.
In terms of brilliance, Venus is the third luminary of the sky, if the Sun is considered the first, and the second -. It is not surprising that it can sometimes be seen during the day as a white dot in the sky.
The orbit of Venus lies within the orbit of the earth, and it goes around the sun in 224 days, or 7 ½ months. The fact that Venus is closer to the Sun than the Earth, and lies the reason for the peculiarities of its visibility. Like Mercury, Venus can move away from the Sun only a certain distance, which does not exceed 46 °. Therefore, it sets no later than 3-4 hours after sunset, and rises no earlier than 3-4 hours before morning.
Even in the weakest telescope, it can be seen that Venus is not a point, but a ball, one side of which is illuminated by the Sun, while the other is plunged into darkness.
Watching Venus from day to day, you can see that she, like Moon Mercury, goes through the entire change of phases.
Venus is usually easy to see with field glasses. There are people with such sharp eyesight that they can see the crescent of Venus even with the naked eye. This happens for two reasons: firstly, Venus is relatively large, it is only slightly smaller than the globe; secondly, in certain positions it comes close to the Earth, so that the distance to it decreases from 259 to 40 million km. It is the closest large celestial body to us after the Moon.
Through a telescope, Venus appears to be very large, much larger than the Moon to the naked eye. It would seem that on it you can see a lot of all sorts of details, for example, mountains, valleys, seas, rivers. Actually it is not. No matter how much astronomers looked at Venus, they were always disappointed. The visible surface of this planet is always white, monotonous, and nothing is visible on it, except for indefinite dull spots. Why is it so? The answer to this question was given by the great Russian scientist M. V. Lomonosov.
Venus is closer to the Sun than the Earth. Therefore, sometimes it passes between the Earth and the Sun, and then it can be seen against the background of the dazzling solar disk in the form of a black dot. True, this happens very rarely. The last time Venus passed in front of the Sun was in 1882, and the next time it will be in 2004.
The passage of Venus in front of the Sun in 1761 was observed by M. V. Lomonosov among many other scientists. Carefully watching through a telescope how the dark circle of Venus appears on the fiery background of the solar surface, he noticed a new, hitherto unknown phenomenon. When Venus covered the disk of the Sun by more than half of its diameter, around the rest of the ball of Venus, which was still against the dark background of the sky, a fiery rim suddenly appeared, thin as a hair. The same was seen when Venus descended from the solar disk. came to the conclusion that the whole thing is in the atmosphere - a layer of gas that surrounds Venus. In this gas, the sun's rays are refracted, go around the opaque ball of the planet and appear to the observer in the form of a fiery rim. Summing up his observations, Lomonosov wrote: "The planet Venus is surrounded by a noble air atmosphere..."
This was a very important scientific discovery. proved that the planets are similar to the Earth in their motion. the first observations through a telescope established that the planets are dark, cold balls, on which there is day and night. Lomonosov proved that on the planets, as well as on Earth, there can be an air ocean - an atmosphere.
The air ocean of Venus differs in many ways from our earthly atmosphere. We have cloudy days, when a continuous opaque cover of clouds floats in the air, but there is also clear weather, when the Sun shines through the transparent air during the day, and thousands of stars are visible at night. Venus is always cloudy. Its atmosphere is constantly covered with a white cloud cover. We see it when we look at Venus through a telescope.
The solid surface of the planet is inaccessible to observation: it is hidden behind a dense cloudy atmosphere.
And what is under this cloud cover, on the very surface of Venus? Are there continents, seas, oceans, mountains, rivers? We don't know this yet. The cloud cover makes it impossible to notice any details on the planet's surface and find out how fast they move due to the planet's rotation. Therefore, we do not know how fast Venus rotates around its axis. We can only say about this planet that it is very warm on it, much warmer than on Earth, because it is closer to the Sun. And it has also been established that there is a lot of carbon dioxide in the atmosphere of Venus. As for the rest, only future researchers will be able to tell about it.
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> > Venus - morning and evening star
Morning and evening star Venus- the second planet of the solar system: the third brightest in the sky, observations from the Earth by the Greeks and Egyptians, two different stars.
You may have heard that in ancient times Venus had two remarkable nicknames: morning and evening star. Well, we are not talking about a bright star in the sky at all. Where did it even come from?
Venus is the morning and evening star in the sky
The orbit of Venus around the Sun passes through the Earth's route. Compared with the outer planets of the solar system, the second is located close to the star. When it is on one side of the Sun, it seems to pull it along and becomes visible in the dark sky. At maximum luminosity, Venus is shown a couple of minutes after the solar disappearance. It was then that she was called the Evening Star.
Venus also becomes on the other side of the star. Then it rises in the morning hours before sunrise and is called the Morning Star. When the Sun brightens the sky, we cannot see it.
In fact, the Egyptians and Greeks believed they were observing two different celestial bodies. In ancient Greece, they were called Phosphorus (giving light) and Hespers (evening star). As a result, they came to the conclusion that they are dealing with a single object and it is not at all a bright star in the sky.
The planet Venus is one of our closest neighbors. Only the Moon is closer to us (excluding, of course, artificial Earth satellites launched in the last few years). Venus is visible as a very bright celestial object.
This planet is especially interesting because in many ways it is an almost exact twin of our Earth. The dimensions and mass of Venus are approximately the same as those of the Earth, so there is reason to expect similar physical conditions on both planets. Unfortunately, we cannot directly observe the surface of Venus, because its atmosphere is an insurmountable obstacle for our telescopes. Therefore, our knowledge of Venus is much more scarce than of Mars, although the latter is further from us and smaller in size. In this book, I intend to summarize the results that astronomers have been able to accumulate and indicate possible directions for further research. Venus is a mysterious world, but it seems that our attempts to explore it are finally becoming successful.
The solar system consists of one star - the Sun and nine main cries, as well as a huge number of smaller celestial bodies. The planets do not have their own glow; they only reflect the sun's rays and seem bright only because of their relative proximity. They revolve around the sun in elliptical paths called orbits; the average distances of the planets from the Sun are in the range of 58 million km for Mercury. In ancient times, however, they thought differently: the Earth was considered the center of the Universe, and the celestial bodies were considered deities.
The five planets are Mercury, Venus. Mars, Jupiter, Saturn must have been known since prehistoric times, and even in ancient times it was noted that although the planets look like stars, they behave quite differently. Real stars seem to be stationary on the celestial sphere and participate only in its daily rotation, so that the Chaldean shepherd astronomers thousands of years ago saw the same outlines of the constellations as we do. The planets Mars, Jupiter and Saturn, on the contrary, wander among the stars within a certain belt in the sky known as the Zodiac. Mercury and Venus also move in this belt, but at the same time follow the Sun as it moves among the stars (which gave reason to consider them closer to us than the Sun).
Venus, the brightest luminary after the Sun and Moon, is never visible in the sky during the entire night. Either it sets as an evening star a few hours after the Sun, or as a morning star it appears shortly before sunrise. At one time, it was believed that the morning and evening stars are different celestial bodies, and not the same planet. In Egypt, for example, the evening star was known by the name of Owaiti, and the morning star by Thiomoutiri; however, in China she was called by one name Tai-pi, or White-faced Beauty.
The Babylonians called Venus Ishtar (the personification of the woman and mother of the gods) and described her as "the bright torch of heaven." Temples were erected in her honor in Nineveh and in many other places. It was believed that Ishtar sends abundance to people. An ancient legend says that when Ishtar went to the realm of the dead to find her deceased beloved Tammuz, all life on Earth began to fade and was saved only thanks to the intervention of the gods, who resurrected Tammuz and returned Igatar to the living. The analogy with the ancient legend of Demeter and Persephone is obvious.
The association of the planet with a woman took place among all peoples, except, perhaps, the Indians. This is quite natural, since Venus appears to the earthly observer as the most beautiful of the planets. The Greeks and Romans gave the name to the goddess of beauty, and temples to Venus were erected in many places, such as Cyprus and Sicily. The month of April was dedicated to the Goddess. In fact, the cult of Venus persisted until very recently. Williamson testifies that back in the 19th century. and Polynesia made human sacrifices to the Morning Star; sacrifices were also performed by the Skaidi Pawnee Indians in Nebraska. It takes many years for the ancient beliefs to die out.
Even Homer mentioned Venus: "Hesperus is the most beautiful of the stars of heaven." The earliest records of observations of the planet that have come down to us, apparently, were made in Babylon. However, astronomy stood firmly on its feet as a science only in antiquity. It became known that the Earth is not a plane, but a ball, and other planets are also balls. If the Greeks take one more step and overthrow our planet from its honorary throne at the center of the universe, it seems that the progress of mankind would accelerate. Some philosophers and scientists, and above all Aristarchus of Samos, did this, but their ideas were contrary to religious dogmas, and subsequently the ancient Greeks returned to geocentrism.
The ancient Greek system of the world received its highest development in the works of Hipparchus and Ptolemy. Claudius Ptolemy, who died around 180 AD, left us a work ("Almagest" - Ed.), reflecting the level of knowledge during the decline of ancient culture. This system is known as the "Ptolemaic system", although, in fact, Ptolemy was not its main author.
According to these ideas, the Earth is at the center of the Universe, and various celestial bodies revolve around it in "perfect" circular orbits. Closest of all other bodies to the Earth is the Magnifier, then Mercury, Venus and the Sun, then the other three planets known at that time - Mars, Jupiter, Saturn and, finally, the stars.
Already in the time of Ptolemy, it was obvious that such a system of the universe is facing significant difficulties. For example, the planets do not move continuously among the stars from west to east: Mars, Jupiter and Saturn can stop for a few days, then go back, making a “reverse” movement, and then start moving again in the same direction - east. To get rid of this difficulty, Ptolemy, who was an excellent mathematician, suggested that the planet moves in a small circle, or "epicycle", the center of which in turn revolves around the Earth in a large circle - "deferent". The possibility that the planets could move in elliptical orbits was not allowed. The movement in a circle was considered the most perfect form of movement, and nothing but absolutely perfect, of course, could happen in heaven.
New problems arose for Mercury and Venus, and Ptolemy was forced to assume that the centers of their epicycles were constantly in a straight line with the Sun and Earth. This at least explained why both planets never appear in the opposite side of the sky from the Sun. However, the whole system turned out to be too artificial and cumbersome.
At the beginning of the XVII century. the telescope was invented, and in 1609 Galileo Galilei, professor of mathematics at Padua, first pointed an instrument he had just made to the sky. The scientist immediately saw that his expectations were more than justified. High mountains and huge craters were visible on the Moon; there were spots on the sun; four of its own moons were spinning around Jupiter, and Saturn looked somehow strange, although Galileo could not figure out what was the matter, and the Milky Way turned out to be a huge mass of faint stars.
Galileo himself was an ardent supporter of the heliocentric system of the world, which was resurrected and developed by Copernicus about 60 years earlier. Galileo was looking for confirmation of the validity of this system and found them, oddly enough, by observing the phases of Venus. Yes, Venus did detect phases, but they turned out to be of the same type as those of the Moon: sometimes the planet was observed in the form of a crescent, and sometimes as an almost complete disk.
Galileo's discoveries were met with a storm of indignation. The princes of the church objected furiously; the story of Galileo's arrest, trial, and forced abdication is well known. Many of his contemporaries refused to believe what they saw through telescopes, and Galileo did not live to see that he was right.
Kepler was also on the right track. His research, based on the accurate observations of the Danish astronomer Tycho Brahe, allowed the scientist to derive the famous laws of planetary motion, bearing the name of Kepler. The first of these laws says that each planet revolves around the Sun in an ellipse, at one of the foci of which is the Sun itself; the motion of Venus, as I expected, obeyed this law. At the very end of the century, the work of Isaac Newton, devoted to the problem of universal gravitation, finally clarified the whole picture. Since then, the Ptolemaic system and other geocentric systems have become a thing of the past.
The discovery of the phases of Venus helped open the door to knowledge; the way forward seemed clear.
