Venus is the second planet from the Sun and is Earth’s closest planetary neighbor.
It’s one of the four inner, terrestrial (or rocky) planets, and it’s often called Earth’s twin because it’s similar in size and density.
These are not identical twins, however – there are radical differences between the two worlds.
Venus is the second brightest natural object in the night sky after the Moon
The clouds of sulfuric acid in Venus’ atmosphere make it reflective and shiny and obscure our view of its surface. It's brightness makes it visible during the day if it’s clear and you know where to look
Venus is named after the Roman goddess of love and beauty
It is thought that Venus was named after the beautiful Roman goddess (counterpart to the Greek Aphrodite) due to its bright, shining appearance in the sky. Of the five planets known to ancient astronomers, it would have been the brightest.
Venus was the first planet to have its motions plotted across the sky, as early as the second millennium BC
Because Venus is easy to spot with the naked eye, it is impossible to say who discovered the planet. But over the centuries, we have been able to measure Venus’ motions, such as the rare transit of Venus when the planet appears from Earth to cross in front of the Sun.
We tend to say ‘Venusian’ not ‘Venerian’
Following the rules of Latin, we should say ‘venerean’ as the adjective to describe things related to Venus. However, this is deemed to be too close to the word ‘venereal’. The more commonly used word is ‘Venusian’ despite its clunky etymology.
Venus has been called Earth’s twin because of the similarities in their masses, sizes, and densities and their similar relative locations in the solar system.
Because they presumably formed in the solar nebula from the same kind of rocky planetary building blocks, they also likely have similar overall chemical compositions.
Venus is made up of a central iron core and a rocky mantle, similar to the composition of Earth
Early telescopic observations of the planet revealed a perpetual veil of clouds, suggestive of a substantial atmosphere and leading to popular speculation that Venus was a warm, wet world, perhaps similar to Earth during its prehistoric age of swampy carboniferous forests and abundant life.
Scientists now know, however, that Venus and Earth have evolved surface conditions that could hardly be more different.
Viewed through a telescope, Venus presents a brilliant yellow-white, essentially featureless face to the observer. Its obscured appearance results from the surface of the planet being hidden from sight by a continuous and permanent cover of clouds. Features in the clouds are difficult to see in visible light. When observed at ultraviolet wavelengths, the clouds exhibit distinctive dark markings, with complex swirling patterns near the equator and global-scale bright and dark bands that are V-shaped and open toward the west. Because of the all-enveloping clouds, little was known about Venus’s surface, atmosphere, and evolution before the early 1960s, when the first radar observations were undertaken and spacecraft made the first flybys of the planet.
Until recently, the dense cloud cover on Venus prevented every attempt to get a look at its surface. The U.S. Mariner spacecraft could only send back pictures of a world shrouded in clouds. The real breakthroughs came with Pioneer Venus in 1978, Magellan in 1990, and with two Soviet space probes in 1982. Pioneer Venus was able to do some low resolution mapping of the surface. The two Soviet Venera probes landed on the surface, but could only send back a few poorly aimed pictures before they were destroyed by the intense temperature and pressure. Nevertheless, they did show a barren rocky terrain. Magellan used high definition radar to map the planet in detail, and revealed a relatively young surface. It consists of plains covered by lava flows, and highland regions formed by geological activity. Thousands of volcanoes and numerous impact craters dot the surface. Venus is a very active planet undergoing constant change.
Venus from earth appears like a orange colored planet similar to earth. Similar to earth, It appears as it covered by layers of atmosphere.
The clouds that enshroud Venus are enormously thick. The main cloud deck rises from about 48 km (30 miles) in altitude to 68 km (42 miles). In addition, thin hazes exist above and below the main clouds, extending as low as 32 km (20 miles) and as high as 90 km (56 miles) above the surface. The upper haze is somewhat thicker near the poles than in other regions.
The main cloud deck is formed of three layers. All of them are quite tenuous—an observer in even the densest cloud regions would be able to see objects at distances of several kilometres. The opacity of the clouds varies rapidly with space and time, which suggests a high level of meteorologic activity. Radio waves characteristic of lightning have been observed in Venus’s clouds. The clouds are bright and yellowish when viewed from above, reflecting roughly 85 percent of the sunlight striking them. The material responsible for the yellowish colour has not been confidently identified.
The microscopic particles that make up the Venusian clouds consist of liquid droplets and perhaps also solid crystals. The dominant material is highly concentrated sulfuric acid. Other materials that may exist there include solid sulfur, nitrosylsulfuric acid, and phosphoric acid. Cloud particles range in size from less than 0.5 micrometre (0.00002 inch) in the hazes to a few micrometres in the densest layers.
The reasons that some cloud-top regions appear dark when viewed in ultraviolet light are not fully known. Materials that may be present in minute quantities above the cloud tops and that may be responsible for absorbing ultraviolet light in some regions include sulfur dioxide, solid sulfur, chlorine, and iron(III) chloride.
Venus has a thick, toxic atmosphere filled with carbon dioxide and it’s perpetually shrouded in thick, yellowish clouds of sulfuric acid that trap heat, causing a runaway greenhouse effect. It’s the hottest planet in our solar system, even though Mercury is closer to the Sun. Surface temperatures on Venus are about 900 degrees Fahrenheit (475 degrees Celsius) – hot enough to melt lead. The surface is a rusty color and it’s peppered with intensely crunched mountains and thousands of large volcanoes. Scientists think it’s possible some volcanoes are still active.
Venus has crushing air pressure at its surface – more than 90 times that of Earth – similar to the pressure you'd encounter a mile below the ocean on Earth.
The circulation of Venus’s atmosphere is quite remarkable and is unique among the planets. Although the planet rotates only three times in two Earth years, the cloud features in the atmosphere circle Venus completely in about four days. The wind at the cloud tops blows from east to west at a velocity of about 100 metres per second (360 km [220 miles] per hour). This enormous velocity decreases markedly with decreasing height such that winds at the planet’s surface are quite sluggish—typically no more than 1 metre per second (less than 4 km [2.5 miles] per hour). Much of the detailed nature of the westward flow above the cloud tops can be attributed to tidal motions induced by solar heating. Nevertheless, the fundamental cause of this “superrotation” of Venus’s dense atmosphere is unknown, and it remains one of the more intriguing mysteries in planetary science.
Most information about wind directions at the planet’s surface comes from observations of wind-blown materials. Despite low surface-wind velocities, the great density of Venus’s atmosphere enables these winds to move loose fine-grained materials, producing surface features that have been seen in radar images. Some features resemble sand dunes, while others are “wind streaks” produced by preferential deposition or erosion downwind from topographic features. The directions assumed by the wind-related features suggest that in both hemispheres the surface winds blow predominantly toward the equator. This pattern is consistent with the idea that simple hemispheric-scale circulation systems called Hadley cells exist in the Venusian atmosphere. According to this model, atmospheric gases rise upward as they are heated by solar energy at the planet’s equator, flow at high altitude toward the poles, sink to the surface as they cool at higher latitudes, and flow toward the equator along the planet’s surface until they warm and rise again. Some deviations from the equatorward flow pattern are observed on regional scales. They may be caused by the influence of topography on wind circulation.
Venus (and the planet Mercury) are the only two planets that don't have a single natural moon orbiting them. Figuring out why is one question keeping astronomers busy as they study the Solar System.
Astronomers have three explanations about how planets get a moon or moons. Perhaps the moon was "captured" as it drifted by the planet, which is what some scientists think happened to Phobos and Deimos
(near Mars). Maybe an object smashed into the planet and the fragments eventually coalesced into a moon, which is the leading theory for how Earth's Moon came together. Or maybe moons arose from general accretion of matter as the solar system was formed, similar to how planets came together.
Considering the amount of stuff flying around the Solar System early in its history, it's quite surprising to some astronomers that Venus does not have a moon today. Perhaps, though, it had one in the distant past. In 2006, California Institute of Technology researchers Alex Alemi and David Stevenson presented at the American Astronomical Society's division of planetary sciences meeting and said Venus could have been smacked by a large rock at least twice. (You can read the abstract here.)
"Most likely, Venus was slammed early on and gained a moon from the resulting debris. The satellite slowly spiraled away from the planet, due to tidal interactions, much the way our Moon is still slowly creeping away from Earth," Sky and Telescope wrote of the research.
"However, after only about 10 million years Venus suffered another tremendous blow, according to the models. The second impact was opposite from the first in that it 'reversed the planet's spin,' says Alemi. Venus's new direction of rotation caused the body of the planet to absorb the moon's orbital energy via tides, rather than adding to the moon's orbital energy as before. So the moon spiraled inward until it collided and merged with Venus in a dramatic, fatal encounter."
Venus rotates on its axis backward, compared to most of the other planets in the solar system. This means that, on Venus, the Sun rises in the west and sets in the east, opposite to what we experience on Earth. (It’s not the only planet in our solar system with such an oddball rotation – Uranus spins on its side.)
Were it not for the planet’s clouds, an observer on Venus’s surface would see the Sun rise in the west and set in the east. Venus spins very slowly, taking about 243 Earth days to complete one rotation with respect to the stars—the length of its sidereal day. Venus’s spin and orbital periods are very nearly synchronized with Earth’s orbit such that, when the two planets are at their closest, Venus presents almost the same face toward Earth. The reasons for this are complex and have to do with the gravitational interactions of Venus, Earth, and the Sun, as well as the effects of Venus’s massive rotating atmosphere. Because Venus’s spin axis is tilted only about 3° toward the plane of its orbit, the planet does not have appreciable seasons. Also, Venus’s rotational period slowed by 6.5 minutes between two sets of measurements taken in 1990–92 and 2006–08. Astronomers as yet have no satisfactory explanation for Venus’s peculiar rotational characteristics. The idea cited most often is that, when Venus was forming from the accretion of planetary building blocks (planetesimals), one of the largest of these bodies collided with the proto-Venus in such a way as to tip it over and possibly slow its spin as well.
Venus’s mean radius is 6,051.8 km (3,760.4 miles), or about 95 percent of Earth’s at the Equator, while its mass is 4.87 × 1024 kg, or 81.5 percent that of Earth. The similarities to Earth in size and mass produce a similarity in density—5.24 grams per cubic centimetre for Venus, compared with 5.52 for Earth. They also result in a comparable surface gravity—humans standing on Venus would possess nearly 90 percent of their weight on Earth. Venus is more nearly spherical than most planets. A planet’s rotation generally causes a bulging at the equator and a slight flattening at the poles, but Venus’s very slow spin allows it to maintain its highly spherical shape.