Venus

Venus () is the second planet from Sol. It has no natural satellite. Venus is a terrestrial planet and is sometimes called Terra's "sister planet" because of their similar size, mass, proximity to Sol and bulk composition. It is named after the Roman goddess of love.
Pre-terraforming, Venus was radically different from Terra. It used to have the densest atmosphere of the four terrestrial planets, consisting of more than 96% carbon dioxide. The atmospheric pressure at the planet's surface was 90 times that of Terra. With a mean surface temperature of 735 K (462 °C; 863 °F), Venus was, by far, the hottest planet in the Sol System, even though Mercury is closer to Sol. Venus was shrouded by an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light. It may have had oceans in the past, but these would have vaporized as the temperature rose due to a . The water had most probably evaporated, and, because of the lack of a planetary magnetic field, the free hydrogen had been swept into interplanetary space by the solar wind. Venus's surface used to be a dry desertscape interspersed with slab-like rocks and periodically resurfaced by volcanism.
The terraforming of Venus, starting at 2000 CE, was deemed an extreme success. The terraforming of Venus took about 150 years, with the final major stage ending at 2150 CE. However, the continuation of terraforming officially continued until 2289 CE, which included the construction of an artificial magnetosphere and the introduction of Terran life to Venus. The average of temperature of Venus was lowered to about 21.8°C, only 6.8° above Terra, making most of the planet either arid or tropical. The atmospheric air pressure had been lowered to 1 terran atmosphere, with roughly the same composition as Terra's. Water delivered from ice moons of Pluto provided only 135 meters of ocean depth, only 3.6% of Terra's ocean depth.
==Composition==
=== Surface ===
Pre-terraforming About 80% of the Venusian surface is covered by smooth, volcanic plains, consisting of 70% plains with wrinkle ridges and 10% smooth plains. Two highland continents made up the rest of its surface area, one lying in the planet's northern hemisphere and the other just south of the equator. The planet has few impact craters, demonstrating the surface is relatively young, at most, 600 million years old. In addition to the impact craters, mountains, and valleys commonly found on rocky planets, Venus has some unique surface features. Among these are flat-topped volcanic features, which look somewhat like pancakes and range in size from 20 to 50 km across, and from 100 to 1,000 m high; radial, star-like fracture systems; features with both radial and concentric fractures resembling webs; and circular rings of fractures sometimes surrounded by a depression. These features are volcanic in origin.
Much of the Venusian surface appears to have been shaped by volcanic activity. Venus has several times as many volcanoes as Terra, and it has 167 large volcanoes that are over 100 km across. Venusian craters range from 3 km to 280 km in diameter. No craters are smaller than 3 km, because of the effects of the dense atmosphere on incoming objects. Objects with less than a certain kinetic energy are slowed down so much by the atmosphere that they do not create an impact crater. Incoming projectiles less than 50 metres in diameter will fragment and burn up in the atmosphere before reaching the ground. Venus has two noticeable continents, in contrast to Terra's four continents. These continents comprise about 20% of Venus's surface.
Post-terraforming, Venus closely resembled Terra, with nearly 80% of its surface area being covered by water. Due to the compression of Venus's previous atmosphere, surface elevation deviation is low.
====Conditions====
Venus's surface was hotter than Mercury's, which has a minimum surface temperature of 55 K (−220 °C) and maximum surface temperature of 695 K (420 °C), even though Venus is nearly twice Mercury's distance from Sol and thus receives only 25% of Mercury's solar irradiance. This temperature was higher than that used for . Pre-terraforming, the surface of Venus is often said to resemble accounts of . The surface pressure of Venus pre-terraforming is enough to crush submarines and reinforced structures within hours, if not minutes.
Being terraformed, Venus now closely resembles Terra. Conditions are habitable for most, if not all Terran life, with an average temperature of 21.8°C, about 7° degrees higher than Terra. However, like Terra, Venus also has strange weather. Tornados, hurricanes, and the like.
===Structure===
The similarity in size and density between Venus and Terra means they share a virtually identical internal structure: a core, mantle, and crust. Like that of Terra, the Venusian core is partially liquid because the two planets have been cooling at about the same rate. The slightly smaller size of Venus means pressures are 24% lower in its deep interior than Terra's.
==Dynamics==
=== Hydrosphere ===
Being terraformed, Venus artificially has flowing water on its surface. This water was brought by several of Pluto's moons made of ice. Venus's hydrosphere consists overwhelmingly of its oceans, but has water everywhere: seas, lakes, rivers, groundwater, and in the atmosphere. The deepest underwater point on Venus is about 2.5 kilometers in depth. Similar to Terra, over 98% of the water on Venus is saline.
===Atmosphere===
Venus had an extremely dense atmosphere composed of 96.5% carbon dioxide, 3.5% nitrogen, and traces of other gases, most notably sulfur dioxide. The mass of its atmosphere was 93 times that of Terra's, whereas the pressure at its surface is about 90 times that at Terra's—a pressure equivalent to that at a depth of nearly 1 kilometre under Terra's oceans. The density at the surface used to be 65 kg/m3, 6.5% that of water or 50 times as dense as Terra's atmosphere. The CO2-rich atmosphere used to generate the strongest greenhouse effect in the Sol system, creating surface temperatures of at least 735 K (462 °C).
===Climate and weather===
Billions of years ago Venus's atmosphere was much more like Terra's than it is now, and that there may have been substantial quantities of liquid water on the surface, but after a period of 600 million to several billion years, a runaway greenhouse effect was caused by the evaporation of that original water, which generated a critical level of greenhouse gases in its atmosphere. This was probably caused by Sol transitioning from a young star onto the main sequence.
Winds at the surface used to be slow, moving at a few kilometres per hour, but because of the high density of the atmosphere at the surface, they exert a significant amount of force against obstructions, and transported dust and small stones across the surface. This alone would make it difficult for a human to walk through, even if the heat, pressure, and lack of oxygen were not a problem. Winds on Venus move at up to 60 times the speed of its rotation, whereas Terra's fastest winds are only 10–20% rotation speed. The surface of Venus was effectively isothermal; it retained a constant temperature not only between day and night but between the equator and the poles. Although having a 177 degree tilt, starting from 180 degrees, Venus has a 2.64 degree tilt retrograde, leaving little variation by seasons.
Post-terraforming, climate and weather became much more like Terra, gaining characteristics of its sister planet. Since Venus receives double Sunlight of Terra, most of the planet is subtropical and is often viewed as the 'paradise of the system'. Most of Venus has a climate similiar to Terra's subtropical climate. This subtropic climate rarely sees snow and allows citrus and similiar terran fruits to flourish. 
=== Magnetosphere ===
Like most bodies with no magnetosphere, Venus's magnetic field is artificial and is actually generated from a Motojima ring system. This differs from planets like Terra, whose magnetic field is generated in the core, and differs from planets like Neptune, whose magnetic field is generated in the mantle. Venus's Motojima ring system was developed after the successful terraforming of the planet, completed at around 2188 CE. Venus's magnetosphere extends to about six Venus radii facing Sol. This magnetic field requires roughly 12 GW of constant power which powers cables that carry 6.4 MA currents. This magnetosphere stop solar wind from stripping away atmospheric gases. However, the magnetosphere serves its purpose and stops all solar wind, preventing all sorts of problems.
==Orbit and rotation==
Venus orbits Sol at an average distance of about 0.72 AU (108,000,000 km; 67,000,000 mi), and completes an orbit every 224.7 days. Although all planetary orbits are elliptical, Venus's orbit is the closest to circular, with an eccentricity of less than 0.01.
All the planets in the Solar System orbit the Sol in an anti-clockwise direction as viewed from above Terra's north pole. Most planets also rotate on their axes in an anti-clockwise direction, but Venus used to rotate clockwise in retrograde rotation once every 243 Terran days—the slowest rotation of any planet. Since its rotation was so slow, Venus is very close to spherical. A Venusian sidereal day thus used to last longer than a Venusian year (243 versus 224.7 Terran days). Venus's equator used to rotate at 6.5 km/h (4.0 mph), whereas Terra is approximately 1,670 km/h (1,040 mph). One Venusian year was about 1.92 Venusian solar days, pre-terraforming. Retrograde, Venus has a small tilt of less than 3 degrees, which means it has no noticeable seasons. This results in permanent climate bands. Scientists have a theory on why Venus's rotation is so unique. Early on in the Sol system, there were dozens of Mars-sized objects in the inner system. Venus was perhaps hit by one. In addition to this, it is also possible that Venus's atmosphere slowed down the rotation of the planet itself.
To an observer on the surface of Venus, Sol would rise in the west and set in the east. An explanation for the lack of satellites is the effect of stronger solar tides, which possibly destabilized large satellites that orbited Venus in the past.
Post-terraforming, the speed of Venus was sped up using a Birch drive to roughly 1 Terra day, allowing for the direct implementation of all kinds of Terra-life. However, Venus's rotation post-terraforming did not change in direction and still rotates retrograde. This means that Sol rises in the west and sets in the east. The tilt of Venus also did not change, meaning that it still virtually has no seasons.
== Civilization ==
===History===
==== Initial settlement ====
===== Terraforming =====
The now terraformed Venus is the second most populated object or planet in the Sol system, with over eight billion humans living on the surface. To reverse the runaway greenhouse effect, the Conglomerate had to overcome several issues.
*Reducing Venus's surface temperature of 462 °C (864 °F).
*Eliminating most of the planet's dense 9.2 MPa (91 atm) carbon dioxide and sulfur dioxide atmosphere, via removal or conversion to some other form.
*Addition of breathable oxygen to the atmosphere.
Venus receives about twice Sollight that Terra does, which is thought to have contributed to its runaway greenhouse effect. Terraforming Venus involved reducing the insolation at Venus's surface to prevent the planet from heating up again. The idea of terraforming Venus turned into reality with the Gaia program, and the actual project began in 2000 CE. The terraforming process would cost about $836 trillion, but economists estimated that within 20 years, the colonies on and in orbit around Venus could start generating more money than expenditure on terraforming.
====== First stages ======
The Conglomerate began the terraforming of Venus with the deployment of an extremely large solar shade 250,000,000,000 km in area, manufactured from inner system asteroids. However, cooling was expected to take nearly a century. Other terraforming events were planned during the cooling stages. Following this, an orbital ring and a small habitat is placed in low Venus orbit.
====== Cooling of the atmosphere and cloud colonies ======
In order to aid the cooling of Venus's atmosphere and surface, heat pipes, costing $280 billion, were deployed to cut cooling time in half. By 2005 CE, the first cloud colony on Venus is completed. Auxiliary mirrors and another orbital colony is established above Venus in order to further aid cooling procedure of the atmosphere. Population of colonies above and in orbit around Venus reaches 200,000. The Gaia program breaks even and begins to pay for itself. By the 2010 CE mark, several more small solar shades are deployed and the second cloud colony is established.
Carbon dioxide in the form of rain begins to fall on the surface of Venus by 2020 CE.  The rain has a rate of at 2mm/hr. The lowland plains of Venus begin to fill with carbon dioxide as an ocean forms. The number of cloud colonies increases to 83 and the orbital ring around Venus is heavily renovated as nitrogen-separation operations begin on the ring.
35 years later, 2055 CE, the program continued as 1097 cloud colonies have been established. The heat pipes saved a total of a century at this point, but are dismantled since the temperature was too low for them. By 2095 CE, the cloud colonies began to cover the carbon dioxide ocean at an extremely fast rate. And by 2110 CE, the freezing of the carbon dioxide oceans had been completed, while the covering of the carbon dioxide oceans carried on.
Solshades used in this stage would also be used nearly a century later, near the end of terraforming to keep the average temperature of Venus about 21.8°C (295 K, 72°C).
====== Rotation ======
Although speeding up a planet's rotation seemed impossible early on, The Conglomerate quickly designed the Birch drive to speed up Venus's retrograde rotation up to 24 hours. The drive would utilize light-sail windmills orbiting Sol for kinetic energy, the windmills sending pellets to Venus, mass-streams on Venus catching them, and sending them back to the windmills, effectively speeding up the rotation of the planet. This part of the terraforming process took about thirty years, from 2060 CE to 2090 CE.
====== Water ======
As with any noticeable Terran life, water must always be present primarily in its liquid state. Venus, of course, has no viable water available. If Venus were to become Terra-like, more water would need to arrive from external sources.
Water could be obtained from the sulfuric acid in Venus's clouds, but it would not nearly reach the requirements. Water could also be obtained via combination of hydrogen and carbon dioxide, but it would take too long and would have unnecessarily high costs.
The Conglomerate decided to bring water from objects made of ice originating from the outer system. The primary candidate for this, Pluto, was chosen. Several of its moons were chosen to be sacrificed to Venus. This started at about 2085 CE. The ice moons would be delivered immediately after all the carbon dioxide had frozen and the carbon dioxide ocean covered, wasting no time in terraforming. The ice moons had to swing by Terra and Mars to reduce their velocity at Venus.
Shortly before reaching Venus, the ice moons were split in half, and swung by Venus's poles, entering a 90° around Sol. They would then return to Venus every 112 days, half of Venus's year. Grazing by the atmosphere, the icy debris cooled and sprinkled down on Venus, the overwhelming majority of it landing on Venus directly, providing water for Venus. This would occur for 30 years every 112 days, starting from 2020 CE and ending at 2050 CE, when the last of the ice moons rained down on Venus.
====== Atmosphere tweaking ======
The atmosphere of Venus at this point was still composed of Carbon dioxide and nitrogen, oxygen nowhere to be found. Starting right after the cooling of the planet, algae was deployed to the planet. Over the course of 28 years, they would convert 0.325 atmospheres of carbon dioxide into 0.236 atmospheres of oxygen, about the pressure of oxygen in Terra's atmosphere. This method would also remove any noticeable carbon monoxide remaining in Venus's atmosphere, bringing it down to negligible amounts.
The export of nitrogen had taken place since the earliest stages of terraforming, taking place on the orbital ring. Nearing the end of terraforming, 2150 CE, the amount of nitrogen in the atmosphere had been lowered to 0.764 atmospheres, roughly Terra's percentage of atmosphere. Following the completion of atmosphere tweaking, the air on Venus was breathable for humans.
====== Magnetic field and biosphere ======
With Venus looking visually like a copy of Terra, internally it was not. Venus's magnetic field was not naturally viable. Without a new magnetosphere, Venus would lose its atmospheric oxygen over geologic scales. In 2155 CE, The Conglomerate issued the construction of a planetary Motojima ring on Venus. The ring system itself was composed of 12 rings around Venus, powered each by a 1 GW fusion power plant constantly. Totaling 12 GW of constant power. This ring would put the nail in the coffin for terraforming, bringing the same level of protection Terra's magnetic field would. The construction of the Venus's Motojima ring was completed in 2188 CE. By this time, a biosphere had already taken stead on the planet, specifically Terra's most successful plants, their consumers, and the consumers' predators. By 2200 CE, 300,000 species of Terran life had been deployed to Venus.
===Economy and human geography===
Venus itself has a Terra-like economy. Due to terraforming, Venus is self-sufficient and is able to support a high population. As Venus is able to support a high population, its economy has no specific purpose and has a wide array of fields; similiar to all Terra-like planets or moons. Due to the higher UV radiation Venus receives, most of the inhabitants of Venus have a brown or caramel skin tone. Human inhabitants with pale skin can get sunburn even indoors due to the amount of radiation Venus recieves. Venus is often considered one of the three most important places in the Sol system, along with Terra and Mars. Most of Venus's population lives in quite comfortable regions of the planet, in between the dry, arid, desert areas, and the wet, humid, tropical rainforests.
Category:Planets
Category:Sol system
Category:Terra-like