But the planet Venus, contrary to its calm appearance, is very turbulent and restless. 96% of Venus’s atmosphere is made up of carbon. The pressure on the surface of the planet Venus is more than 90 times the pressure on the surface of the Earth. Such pressure exists only at a depth of 900 meters in the Earth’s seas. Despite the closer distance of Mercury to the Sun, Venus is the hottest known planet in the solar system, and the average temperature of its surface reaches 471 degrees Celsius. Venus is covered with a thick layer of sulfuric acid reflective clouds. Clouds prevent sunlight from reaching the surface of this planet and reflect the light. The strong reflection of sunlight is the main reason why Venus shines above the night sky and is visible to the naked eye. The surface of Venus is dry and full of slate-like rocks and volcanic activity.

A year on Venus is equal to 224.7 Earth days, But the movement of Venus is slow, and for this reason, the longest day among the planets of the solar system belongs to this planet. One Venus day is equal to 243 Earth days. Unlike other planets, Venus rotates clockwise around its axis. This means that the sun rises in the west of Venus and sets in the east. Venus also has no moons.

As the brightest object in the night sky, Venus has played a prominent role in human culture since ancient times. This planet is the holy god of many cultures and has inspired many writers and poets with nicknames such as Morning Star or Evening Star. The other name of this planet, Venus, is derived from the Roman goddess of love and beauty. In the second millennium BC, the movements of Venus in the night sky were mapped for the first time. Because of its small distance from the Sun, Venus has been the target of interplanetary probes many times.

The astrological symbol of the planet Venus is the same symbol used in biology for the female gender. A circle with a cross below it. The symbol of Venus also means femininity and in Western alchemy, it represents the metal copper.

The planet Venus is one of the prominent indicators of the night sky, as a result, it has had a high importance in mythology, astrology, and science fiction texts of different cultures. In Sumerian religion, Inanna is associated with the planet Venus. Classical poets such as Homer, Sappho, and Vigil also spoke about the star of Venus and its light. Poets such as William Blake, Robert Frost, Elizabeth Landen, Alfred Lord Tennyson, and William Wordsworth have also written odes about it.

In Chinese culture, the planet Venus is called Zinxing, the golden god of the metal element. In India, Shukra Graha (Shukra planet) is derived from the powerful holy Shukra, which in Sanskrit means pure, pure, or shine and purity. Mayan civilization considered Venus to be the most important astronomical object after the Sun and the Moon. Ancient Egyptians and Greeks considered Venus to be two separate bodies, one of which was the morning star and the other the evening star.

The planet Venus to the right of the tree in Vincent Van Gogh’s 1889 painting of the starry night sky

According to the core accretion model, initially, the rocky cores of the planets were formed; Then the lighter elements formed the mantle and crust of the planets. On rocky worlds, other lighter elements made up the atmosphere. By examining the outer planets (outside the solar system), the core accumulation theory can be considered as the dominant theory of formation. Stars with more metal in their cores (a term astronomers use for elements other than hydrogen and helium) have larger planets in their systems than stars made only of metal.

Since the size, mass, density, and composition of Venus and Earth are almost equal, the title of twins or sister has been given to these two planets. The diameter of Venus is 12103.6 km and only 638.4 km less than Earth. However, the similarities end there. Venus is not the closest planet to the Sun, but it is the hottest planet in the solar system due to its dense atmosphere and ability to trap heat and the greenhouse effect (a situation in which, due to positive feedback between the surface temperature and the atmosphere, the greenhouse effect is intensified and the oceans evaporate). Is. As a result, the temperature on the surface of Venus even reaches 471 degrees Celsius, which easily melts lead. For this reason, probes that have already landed on the surface of Venus lasted only a few hours.

The internal structure of Venus is probably similar to that of Earth. Like Earth, Venus is a rocky planet composed of rock and metal and probably has a molten metal core, a rocky mantle, and a crust. Since Venus is slightly smaller than the Earth, the pressure in its depths is 24% lower than the pressure in the depths of the Earth. The main difference between the two planets is the absence of tectonic plates on the surface of Venus. The reason for this problem can be the high strength of the crust of Venus.

The surface of Venus has been the subject of many investigations by planetary scientists in the 20th century. Venus rovers in 1975 and 1982 sent images of angular rocks and surface sediments on Venus. The mapping of the surface of Venus was done by the Magellan probe in 1990 and 1991. The surface of Venus shows evidence of volcanic activity, and sulfur in the atmosphere may also be a product of this activity. Six mountainous regions make up one-third of the surface of Venus. One of the areas known as Maxwell is approximately 870 km wide and its mountains are 11.3 km high, which are the highest mountains on this planet.

Most of the surface of Venus was formed by volcanic activity. The number of volcanoes on Venus is seven times that of Earth. Although there are a total of 1,600 volcanoes on the surface of Venus, they do not seem to be active. Venus has a total of 167 large volcanoes that are more than a hundred kilometers wide.

However, the radars of the Magellan probe found evidence of volcanic activity in the Moat Mons region of Venus, which was seen in the form of gray streams near the summit and southern slope of the mountain. This probe also managed to discover impact holes on the surface of Venus, although their number was very small; Because volcanic lava covered them.

Almost a thousand impact craters have been discovered on Venus, which are evenly distributed. In other planets such as Earth and Moon, the cavities undergo erosion and collapse. For example, the craters of the moon collapsed due to subsequent collisions, while the erosion factors of the impact craters of the earth are water and wind. Approximately 85% of Venus impact craters are new. Although the Earth’s crust is constantly moving, such a process does not exist on Venus. The diameter of Venus impact craters varies from 3 to 280 km.

The crust of Venus is older due to the accumulation of lava on it; But the Earth’s oceanic crust has been replaced by tectonic plates and its average age is 100 million years; While the average age of the crust of Venus is 300 to 600 million years. Now the question is raised that considering the conditions and harsh weather, why are the volcanic activities of Venus small compared to Earth?

According to Dr. Mikhail from the Faculty of Environmental Sciences (a geologist at St. Andrews University), due to the extreme heat, the integrity of the crust of Venus is less than that of Earth, and magmas (lavas) cannot enter the crevices of the crust and lead to renewed volcanic activity. The soft, plastic-like crust of Venus prevents the formation of tectonic plates (plate tectonics are a geological phenomenon that plays a very important role in the Earth’s carbon cycle and is essential for climate).

Investigating the environmental and geological differences of these two twin planets is the key to discovering extrasolar planets and the reason they are habitable (like Earth) or uninhabitable (like Venus). The Venus Express orbiter from the European Space Agency also managed to discover new evidence of volcanic activity on the surface of Venus; So that the volcanic eruptions in some places caused the temperature to rise up to 800 degrees Celsius.

The atmosphere of Venus is almost completely composed of carbon dioxide. The atmosphere of this planet also has small amounts of nitrogen and clouds of sulfuric acid. This combination results in a greenhouse effect that makes the planet’s surface even hotter than Mercury. In addition to the intense heat, the planet is surrounded by heavy clouds that act like a reflective shield, protecting it from meteorite bombardments. However, numerous craters and craters can be seen on the surface of this planet.

The constant speed of Venus’s winds reaches 360 km/h. Wind speed decreases near the surface and reaches several kilometers per hour. On Earth, seasons change based on Earth’s axis; When one of the hemispheres is closer to the sun, the temperature in that hemisphere increases; But on Venus, much of the sun’s heat cannot pass through its thick atmosphere. As a result, the temperature difference during a year and the difference between day and night temperature of this planet is not much.

Research shows that the atmosphere of Venus was like the Earth’s atmosphere billions of years ago, But 600 million years of greenhouse effect resulting from water evaporation brought the level of greenhouse gases in the atmosphere of this planet to a critical limit. Even before this happened, the surface of Venus was not habitable like Earth, but there was a possibility of life in the upper layers of Venus’ atmosphere.

The clouds of Venus are mainly composed of sulfuric acid. In addition, one percent of Venus’ atmosphere consists of ferric chloride. Other possible substances in clouds include ferric sulfate, aluminum chloride, and phosphoric anhydride. Clouds at different levels have different compositions and the way they are distributed is different. The clouds of Venus reflect almost 90% of sunlight and prevent sunlight from reaching Earth.

According to a hypothesis, the planet Venus had a different face in the distant past. According to studies, Venus was probably a habitable world like Earth billions of years ago. One of the parameters influencing the harsh environment of this planet is its slow axial rotation (rotation around itself). So one day on Venus is equal to 243 Earth days or two-thirds of an Earth year; Therefore, in any part of this planet, sunlight lasts for months. According to the simulations, Venus probably had oceans early in its life, but tidal forces from the oceans slowed the planet’s rotation and eventually evaporated the oceans.

But based on NASA’s clues and past missions, Venus probably wasn’t as hellish in the past, it had blue oceans, a thinner atmosphere, and a faster rotation. All these criteria could make Venus a true paradise. According to new research by scientists at NASA, the University of Bangor and the University of Washington, the ancient oceans of Venus have been the main cause of its climate changes.

According to this hypothesis, ocean tides have led to a reduction in the speed of the planet’s axial rotation by creating friction between water currents and the sea floor. For example, this process on Earth causes the days to get 20 seconds longer every 1 million years. Assuming the presence of oceans on ancient Venus, such a process probably occurred, and since Venus has no moons, the Sun was the main cause of tides.

But according to another research, the above hypothesis is not true. According to more recent studies, there was no liquid ocean on the surface of Venus from the beginning. Although past researches have pointed to its humid and hot environment based on the chemical characteristics of the atmosphere and high areas of Venus, more recent researches have shown that the high points were formed by molten materials and not water. In general, there is still little information about the formation and past of the planet Venus. As future missions launch more probes to the planet, more secrets about its formation and past will be revealed.

About two years ago in 2020, scientists reported the presence of a gas called phosphine among the acidic clouds of Venus . This gas could be a sign of life on this hellish planet. Because of how phosphine forms on Earth, it was surprising to find even a small amount of this gas on Venus.

Some scientists believed that this gas is probably the result of the activity of small living organisms that live in the clouds of Venus, and another group considered it the result of the volcanic activities of Venus. On the other hand, even the idea of ​​life on the hellish planet Venus seemed funny because the surface temperatures of this planet can even melt lead or the clouds of Venus are full of toxic and acidic gases and life cannot be imagined in them.

However, phosphine gas could upset all the equations. A group of scientists also believed that waiting for the discovery of life on Venus was futile. According to an analysis by John Hallsworth, a microbiologist at Queen’s University in Belfast, the lack of water in Venus’ clouds prevents life from growing in the planet’s atmosphere. At least there is no possibility of the growth of life similar to Earth in the atmosphere of this planet; Because living things need water to grow.

However, a detailed and new analysis of the chemical state of the clouds of Venus shows that none of the biological indicators of aerobic life with sulfur metabolism exist in it; As a result, the mystery of discoverable life in the clouds of Venus is largely solved, and at least until we get new information, this conclusion will remain valid. The complex chemical properties of Venus’ upper atmosphere cannot be easily described based on life as we know it. Finally, future discoveries and missions will reveal more about the above results. The definitive conclusion so far is that there is no trace of life in the clouds of the planet Venus.

According to the observations of Venus 4 probe in 1967, the magnetic field of Venus is much weaker than the magnetic field of Earth. The magnetic field is created by the interaction between the ionosphere and the solar wind. The small magnetosphere of Venus is not strong enough to protect its atmosphere from cosmic rays. The weak magnetosphere around Venus means that the solar wind interacts directly with the outer atmosphere. Here, hydrogen and oxygen ions are produced by the decomposition of neutral molecules from ultraviolet rays.

Due to the slow rotation of Venus around its axis, one Venus day is equal to 243 Earth days; And in this way, it has won the record of the longest day in the solar system. Venus is located at a distance of 0.72 AU (108 million kilometers) from the Sun, and its orbit around the Sun is equal to 224.65 Earth days. When Venus is between the Earth and the Sun, inferior conjunction occurs; This means that this planet is at the closest distance to Earth (41 million km). This happens every 584 days.

Venus is on the border of tidal lock. According to the tidal lock, one side of the smaller mass is permanently facing the larger mass. For example, the Moon is tidally locked relative to the Earth, and Earth residents always see one side of the Moon. Unlike other planets, Venus orbits the Sun in the opposite direction. The thick atmosphere of Venus prevents this planet from being completely locked to the Sun.

Venus does not have a natural moon, But instead, it has several asteroids: the asteroid 2002 VE68 and two other transient asteroids, 2001 CK32 and 2012 XE133.

Considering the physical characteristics and atmospheric conditions, suppose you want to travel to Venus. Although such a situation is impossible in reality and Venus is a planet you may never want to see! But you can better understand its conditions with an imaginary trip to Venus. On an imaginary trip to Venus, finding a landing position is almost impossible. Even if you manage to land on its surface, Venus’s atmosphere is full of toxic clouds of sulfur dioxide.

At the beginning of the descent, you will face strong winds (approximately 360 km/h), at a distance of 48 km in the atmosphere, the winds will subside and you will enter a toxic fog. The rains of Venus are composed of sulfuric acid, but the rain never reaches the surface of Venus; Because the atmosphere is so hot that they evaporates in the middle of the road. After leaving the fog, you will experience a temperature of 315 degrees Celsius and the pressure is ten times that of the seas on the surface of the earth.

You experience such heavy pressure only at a distance of 800 meters from the earth’s oceans; But after landing on the surface, the temperature will reach 471 degrees Celsius; A temperature that easily melts lead. Contrary to popular belief, the temperature is not lower at the poles of Venus. Venus spins hard on its axis and the temperature is almost the same across its entire surface. Now suppose you can get out of your spaceship.

Walking on Venus is a very difficult task. The clouds of Venus reflect 90% of the sunlight, so the light hardly reaches the surface and you can hardly see anything up to a few kilometers away. In such conditions, the rate of oxygen consumption will increase. 96% of Venus’ atmosphere is carbon dioxide, 3.5% is nitrogen, and less than 1% of the rest is carbon monoxide, argon, sulfur dioxide, and water vapor.

In such conditions, the risk of damage to cells and cancer will increase. Given that Venus has no known magnetic field, then you will be bombarded with energetic cosmic rays. On the other hand, your weight will be less on the surface of Venus because the mass of Venus is 91% of the mass of Earth. In the past, it was thought that there was a tropical paradise under the clouds of Venus, until in the 20th century, spacecraft revealed the hellish face of Venus.

After the Moon, Venus is the brightest object in the night sky that can be seen with the naked eye. The reason why Venus shines above is its thick cloud layer that reflects more than 90% of sunlight. For this reason, the characteristics of the surface of Venus remained a mystery for a long time.

Like the moon, Venus appears in a complete cycle of phases. The changes of Venus can be observed in monthly intervals. When Venus is at its maximum distance from the Sun, it appears as a large, bright disk.

A transit of Venus occurs when the planet passes directly between the Sun and a larger planet. During the transit, Venus can be seen from Earth as a small black dot that passes in front of the Sun. Transits of Venus usually occur in 243-year cycles with a pattern of two pairs of transits at an interval of eight years and at intervals of 105.5 years or 121.5 years. This pattern was discovered in 1639 by the English astronomer, Jeremy Horrocks. The last pair of transitions occurred on June 8, 2004, and June 2012. The previous transit couple occurred in December 1874 and December 1882; The next transit couple will occur in December 2117 and December 2125.

Until the 20th century, little was known about Venus. With the discovery of spectrometers, radars, and ultraviolet observations, more information about this planet was obtained. The first ultraviolet observation of Venus was made in the 1920s. The ultraviolet images showed remarkable details that were not visible in infrared and visible images. The yellow and dense atmosphere of Venus along with cirrus clouds were discovered in this research. The first clues to the orbit of Venus came from spectroscopic observations in the 1900s. Radar observations in the 1970s reveal more details of Venus’ surface for the first time. In these observations, the existence of Maxwell’s mountains was proved.

The first robotic interplanetary probe to visit Venus was the Soviet Union’s Venera probe, launched in 1961. On the other hand, the United States achieved its first success in exploring Venus with the Mariner 2 mission on December 14, 1962. This mission was the first interplanetary mission to collect data from the planet’s atmosphere.

On October 18, 1967, the Soviet Union’s Venera 4 successfully entered Venus’ atmosphere and developed science programs. Venera 4 showed that the surface temperature of Venus is hotter than that calculated by Mariner 2 (approximately 500 degrees Celsius); It also showed that 95% of the atmosphere of Venus consists of carbon dioxide and proved that the density of the atmosphere of this planet is beyond imagination. A Soviet-American science team analyzed data from the Venera and Mariner missions in the years after the mission.

In 1974, Mariner 10 visited Venus on its way to Mercury and recorded some ultraviolet images of it that showed the high speed of Venus’ atmospheric winds. In 1975, the Venus rovers 9 and 10 sent back the first black-and-white images of the surface of Venus. In 1982, Venera 13 and 14 sent back the first color images.

NASA obtained more information about Venus in the form of two separate Pioneer missions, the Pioneer orbiter and the Pioneer probe. The successful Soviet Venera program ended in 1983 with Venera 15 and 16. Other spacecraft, which had a purpose other than Venus, passed by Venus several times in the 1980s and 1990s, including Vega 1 (1985), Vega 2 (1985), Galileo (1990), Magellan (1994), Cassini, Huygens (1998). ) and Messenger (2006) pointed out.

But Venus Express was another unprecedented mission launched by the European Space Agency for a long-term study of Venus’ atmosphere and entered Venus’ orbit in April 2006. The probe was equipped with seven scientific instruments and sent unprecedented data. Japan’s Akatsuki orbiter was launched on May 20, 2010. At first, this probe could not be placed in the orbit of Venus; But after five years, scientists regained control and were able to place it in the orbit of Venus. This orbiter investigates the atmosphere of Venus.

Gallery of images of Venus missions and explorations

Venus Express was the first mission of the European Space Agency to Venus and the second mission of this organization to the Sun. This 1.2-ton spacecraft orbited Venus for eight years and monitored the long-term atmospheric patterns of the planet and used several instruments to study the conditions of the clouds and surface of Venus. The Venus Express mission ended in December 2014 after the spacecraft ran out of fuel.

This spacecraft found important information such as the existence of auroras; Meanwhile, Venus lacks the magnetic field necessary to maintain auroras. Venus Express reached its destination on April 11, 2006, after traveling 400 million kilometers. The mission duration of this spacecraft was 486 days. The conditions of Venus are very unfavorable for the probe landing due to the high temperature of the surface of this planet. On the other hand, the dense clouds of Venus do not allow surface observation.

Venus Express used ultraviolet to infrared imaging instruments to photograph the surface of Venus. This probe was also equipped with a plasma analyzer, magnetometer, and a radar depth gauge to measure the atmosphere and environment around the planet. In the continuation of this mission, evidence of a vortex around the planet’s south pole was reported, which was similar to another vortex at its north pole. In June, the European Space Agency announced the discovery of an atmospheric vortex called a double eye around the south pole of Venus.

In 2011, changes were observed in this vortex. The shape of this vortex was sometimes in the shape of the English number 8 and sometimes in the shape of the letter S. According to scientists, the reason for the formation of these eddies is the currents in the meridian orbit and the poles of this planet. Since Venus’ clouds are very thick and difficult to penetrate, Venus Express used another method to probe the surface of the planet. In 2006, researchers were able to detect heat emitted from the planet’s molten crust. Infrared heat can pass through certain holes in the planet’s atmosphere and enter space, and the spacecraft feels this heat. Therefore, scientists were able to make the first temperature map of the southern hemisphere of Venus.

By September 2007, Venus Express had been in orbit for 500 days and its mission was extended. Despite the harsh environment and radiation around the planet, the spacecraft was in good condition and sent back new information about the planet’s changing atmosphere. The new observations showed daily changes in the air currents of Venus. In addition, scientists discovered a new isotope of carbon dioxide that plays an important role in the planet’s greenhouse effect.

In the following years, Venus Express discovered evidence of volcanoes on Venus by examining sulfuric acid (one of the common products of volcanoes) and investigating strange phenomena such as storms. In March 2012, Venus Express was temporarily blinded by a massive solar storm. Star tracking cameras helped the spacecraft stay on track, But the spacecraft had lost its sight.

According to Venus Express observations, the magnetic coupling with the tail resulted in a 3,400 km wide magnetic plasma bubble that lasted only 94 seconds. Between June and July 2014, Venus Express explored the upper atmosphere of Venus. The aim of this study was to obtain more information about the characteristics of the atmosphere of Venus. In the same year, the operation of this spacecraft ended forever due to running out of fuel.

Venus is hellishly beautiful: its clouds are made of sulfuric acid, and its surface is hot enough to melt lead. Its winds are strong and stormy; For this reason, none of the probe robots have been able to survive more than two hours on the rough surface of this planet, but scientists are looking for a better understanding of the events on the surface of this planet, and accordingly, their future plan is to land strong surfacers on the planet.

During several weeks of negotiations with their European counterparts, NASA scientists prepared three new missions to Venus in 2021, which will be launched in the early 2030s. In a few short weeks in June 2021, NASA committed to planning two missions to Venus, VERITAS and DAVINCI, while the European Space Agency launched the EnVision mission. All three missions will begin their observations in the early 2030s and revolutionize scientific research on the planet Venus.

VERITAS, scheduled for launch in 2027, will survey Venus’ thick clouds and provide the first view of Venus’ surface since the Magellan mission in 1994. The spacecraft’s instruments will provide data on the planet’s rock composition, geological activity, and interior.

Another NASA mission called DAVINCI will be launched in the late 2020s. After surveying Venus’ atmosphere, the spacecraft will drop a probe to the planet’s surface, and it will take about an hour for the probe to reach the surface. The probe will take thousands of measurements and send back detailed images of Venus’ surface. Another mission, the European Space Agency’s EnVision, will make detailed observations of Venus. NASA, as one of the key partners of this mission, will install a hybrid radar instrument on this probe, which will make high-quality measurements of the planet’s surface features.