History UsefulNotes / Venus

Much of Venus' surface was shaped by extensive volcanism in its past. Over 90% of its surface is covered in basalt which would actually make the planet beneath the atmospheric veil appear black from our eyes,[[note]]The reason the ''Magellan'' radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, none of them are currently active, and none have been observed to have erupted recently --[[https://phys.org/news/2017-05-mystery-rare-volcanoes-venus.html explanations]] include that the intense heat causes the Venusian crust to be malleable compared to Earth's one and magma gets stuck on it having difficulties to reach the surface, as it's unable to break through the crust. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead or almost so), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons and later on others as Idunn Mons having been observed to be bright on the infrared. With Venus' hellish conditions, getting a seismometer on the surface to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off. It does not help either that unlike for both Mars and the Moon, there're no meteorites[[note]]Rocks sent to space after a [[ColonyDrop asteroid impact]] powerful enough to overtake their gravities[[/note]] known to have come from Venus.

The thick cloud layer has rendered any optical observation of the surface from orbit impossible. Because of this constant obstacle, outside of images taken from the ''Venera'' landers, scientists must rely on radar imaging to peer through the clouds and make out details of what's below. Unfortunately, many images from orbit, like the famous ''Magellan'' [[https://media.wired.com/photos/5e59ad2b79c7100008eb6ae8/master/w_1600%2Cc_limit/photo_space_venus_1_S91-50688.jpg radar map]], are not accurate to what Venus actually looks like with its clouds off, and have been colorized to bring out detail. In reality, Venus's surface as noted above would resemble a global volcanic lava field, and at that scale would be flat black. Even images of Venus with its clouds still on are usually wrong. Venus actually looks [[http://planetary.s3.amazonaws.com/image/3447783055_7201387b94_o.png like this]]; but it's easy to see why that image isn't widely circulated. Any layman glancing at it would [[RealityIsUnrealistic just assume it was black and white]].

These rather depressing details were revealed by the Soviet ''Venera'' space probes, sent to the planet in the late 1960s. Before that time, many ScienceFiction authors held out hope that Venus might harbor life. Such hope was flimsy at best even before the ''Venera'' space probes, though; as early as the 1890s, spectrographs of the Cytherean atmosphere showed it to be made almost entirely of carbon dioxide, with ''no'' water vapor at all (meaning the clouds ''could not'' have been water clouds like those on Earth). Not to mention that Venus has no moon; Earth's own Moon (which is unusually large in proportion to the planet) is well known to be essential to Earth's habitability.[[note]]Given its similar size to Earth and that planetary collisions are thought to have been rather common during the formation of the solar system, the fact that Venus has no moon is somewhat surprising. This has led to the hypothesis that Venus ''used'' to have a moon, but it was destroyed by yet another impact event, possibly the same one that caused Venus's "backwards" rotation. Or that said moon was lost due to the Sun's tides, much stronger there than those exerted on Earth by the Daystar[[/note]] Although the the top of the cloud layer was relatively cool, in 1962 the ''Mariner 2'' probe revealed that the surface was several hundred degrees Celsius.

The thick cloud layer has rendered any optical observation of the surface from orbit impossible, so outside of images taken from the ''Venera'' landers, many images from orbit, like the famous ''Magellan'' [[https://media.wired.com/photos/5e59ad2b79c7100008eb6ae8/master/w_1600%2Cc_limit/photo_space_venus_1_S91-50688.jpg radar map]], are not really accurate to what Venus actually looks like with its clouds off, and have been colorized to bring out detail. In reality, Venus's surface as noted above would resemble a global volcanic lava field, and at that scale would be flat black. Because of this constant obstacle, scientists must rely on radar imaging to peer through the clouds and make out details of what's below. Even images of Venus with its clouds still on are usually wrong. Venus actually looks [[http://planetary.s3.amazonaws.com/image/3447783055_7201387b94_o.png like this]]; but it's easy to see why that image isn't widely circulated. Any layman glancing at it would [[RealityIsUnrealistic just assume it was black and white]].

The thick cloud layer has rendered any optical observation of the surface from orbit impossible, so outside of images taken from the ''Venera'' landers, many images from orbit, like [[https://media.wired.com/photos/5e59ad2b79c7100008eb6ae8/master/w_1600%2Cc_limit/photo_space_venus_1_S91-50688.jpg the famous ''Magellan'' radar map]], are not really accurate to what Venus actually looks like with its clouds off, and have been colorized to bring out detail. In reality, Venus's surface as noted above would resemble a global volcanic lava field, and at that scale would be flat black. Because of this constant obstacle, scientists must rely on radar imaging to peer through the clouds and make out details of what's below. Even images of Venus with its clouds still on are usually wrong. Venus actually looks [[http://planetary.s3.amazonaws.com/image/3447783055_7201387b94_o.png like this]]; but it's easy to see why that image isn't widely circulated. Any layman glancing at it would [[RealityIsUnrealistic just assume it was black and white]].

Much of Venus' surface was shaped by extensive volcanism in its past. Over 90% of its surface is covered in basalt which would actually make the planet beneath the atmospheric veil appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, none of them are currently active, and none have been observed to have erupted recently --[[https://phys.org/news/2017-05-mystery-rare-volcanoes-venus.html explanations]] include that the intense heat causes the Venusian crust to be malleable compared to Earth's one and magma gets stuck on it having difficulties to reach the surface, as it's unable to break through the crust. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead or almost so), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons and later on others as Idunn Mons having been observed to be bright on the infrared. With Venus' hellish conditions, getting a seismometer on the surface to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off. It does not help either that unlike for both Mars and the Moon, there're no meteorites[[note]]Rocks sent to space after a [[ColonyDrop asteroid impact]] powerful enough to overtake their gravities[[/note]] known to have come from Venus.

Virtually no close-up images of Venus' surface you have ever seen or will ever see is real (with the exception of images taken from the Venera landers). Especially not [[https://media.wired.com/photos/5e59ad2b79c7100008eb6ae8/master/w_1600%2Cc_limit/photo_space_venus_1_S91-50688.jpg this one]]; the famous Magellan radar map (key word on "radar" here). That isn't even a true image of Venus with its clouds off, but has been colorized to bring out detail. In reality, Venus's surface as noted above would resemble a global volcanic lava field, and at that scale would be flat black. The thick cloud layer has rendered any optical observation of the surface from orbit impossible, so scientists must rely on radar imaging to peer through the clouds and make out details of what's below. Even images of Venus with its clouds still on are usually wrong. Venus actually looks [[http://planetary.s3.amazonaws.com/image/3447783055_7201387b94_o.png like this]]; but it's easy to see why that image isn't widely circulated. Any layman glancing at it would [[RealityIsUnrealistic just assume it was black and white]].

Virtually no close-up images of Venus' surface you have ever seen or will ever see is real (with the exception of images taken from the Venera landers). Especially not [[https://media.wired.com/photos/5e59ad2b79c7100008eb6ae8/master/w_1600%2Cc_limit/photo_space_venus_1_S91-50688.jpg this one]]; the famous Magellan radar map (key word on "radar" here). That isn't even a true image of Venus with its clouds off, but has been colorized to bring out detail. In reality, Venus's surface as noted above would resemble a global volcanic lava field, and at that scale would be flat black. The thick cloud layer has rendered any optical observation of the surface from orbit impossible, so scientists must rely on radar imaging to peer through the clouds to make out details of what's below. Even images of Venus with its clouds still on are usually wrong. Venus actually looks [[http://planetary.s3.amazonaws.com/image/3447783055_7201387b94_o.png like this]]; but it's easy to see why that image isn't widely circulated. Any layman glancing at it would [[RealityIsUnrealistic just assume it was black and white]].

Virtually no close-up image of Venus you have ever seen or will ever see is real. Especially not [[https://media.wired.com/photos/5e59ad2b79c7100008eb6ae8/master/w_1600%2Cc_limit/photo_space_venus_1_S91-50688.jpg this one]]. That isn't even a true image of Venus with its clouds off, but has been colorised to bring out detail. In reality, Venus's surface as noted above would resemble a global volcanic lava field, and at that scale would be flat black. Even images of Venus with its clouds still on are usually wrong. Venus actually looks [[http://planetary.s3.amazonaws.com/image/3447783055_7201387b94_o.png like this]]; but it's easy to see why that image isn't widely circulated. Any layman glancing at it would [[RealityIsUnrealistic just assume it was black and white]].

Besides the Moon, Venus is also the best place of the Solar System to see our planet. From there, Earth appears as a dazzling blue star that would be at its closest much brighter than Venus seen from our planet and that with a telescope --Earth would be large enough to appear as a disk with binoculars and even to the Mark I eyeball with sharp enough vision would give a lot of fun as weather patterns change and continents/oceans move below because of its rotation. UsefulNotes/TheMoon would appear almost as bright as we see UsefulNotes/{{Jupiter}}, and while looking much more dull than Earth it would contribute with still more fun for astronomers as the former orbits the latter and both bodies approached, moved away, and in some cases overlapped. Nice AlienSky, if all those clouds were not in the middle.

Besides the Moon, Venus is also the best place of the Solar System to see our planet. From there, Earth appears as a dazzling blue star that with a telescope would give a lot of fun as weather patterns change and continents/oceans move below because of its rotation. UsefulNotes/TheMoon would appear almost as bright as we see UsefulNotes/{{Jupiter}}, and while looking much more dull than Earth it would contribute with still more fun for astronomers as the former orbits the latter and both bodies approached, moved away, and in some cases overlapped. Nice AlienSky, if all those clouds were not in the middle.

Much of Venus' surface was shaped by extensive volcanism in its past. Over 90% of its surface is covered in basalt which would actually make the planet beneath the atmospheric veil appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, none of them are currently active, and none have been observed to have erupted recently --[[https://phys.org/news/2017-05-mystery-rare-volcanoes-venus.html explanations]] include that the intense heat causes the Venusian crust to be malleable next to Earth's one and lava gets stuck on it having difficulties to reach the surface. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons. With Venus' hellish conditions, getting a seismometer on the surface to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off. It does not help either that unlike for both Mars and the Moon, there're no meteorites[[note]]Rocks sent to space after a [[ColonyDrop asteroid impact]] powerful enough to overtake their gravities[[/note]] known to have come from Venus.

Its surface features, long hidden under the constant cloud cover, were finally mapped by the ''Magellan'' space probe using radar in [[TheNineties the 1990s]]. The highest mountain is Maxwell Montes, almost 11 kilometres above the average surface level. If you stood on its peak, it'd be a downright chilly 380°C[[labelnote:*]]716°F[[/labelnote]], and a mere 60 atmospheres of pressure. The culprit for all this heat is the greenhouse effect — Earth's atmosphere is less than 1% carbon dioxide, while Venus's is over 90% carbon dioxide. Earth started with the same amount, [[SealedEvilInACan but it ended up trapped in carbonate rock]]. Venus also started with the same amount of water as the Earth had, but it remained in vapor form (300 atmospheres worth) and created [[UpToEleven a super greenhouse effect]] with temperatures in the ''thousands'' of degrees. [[note]]This plus the slow rotation probably wrecked any chance at plate tectonics; instead of plates constantly sliding against each other, [[LethalLavaLand there seems to be intermittent planet-wide volcanism wiping out many of the planet's surface features every billion years or so]]. [[http://adsabs.harvard.edu/abs/2001Icar..150...19B Some estimations]] suggest said events can cool ''a bit'' the planet as massive clouds of sulphur dioxide and water vapor form, just to be later warmed up to 600°C (1160°F) by the latter, clearing the atmosphere as the former is absorbed by the surface, before going back to those 500°C (900°F) as water vapor is lost and clouds come back. And remember that as the Sun ages it's more luminous, so temperatures can only go up[[/note]] Eventually the water molecules dissociated into hydrogen and oxygen and escaped into space and sank down and fused with the rocks respectively, leaving Venus high and dry. Due to Venus being mythologically associated with femininity, by convention all geographic features there are named after women or female entities, except for Maxwell Montes and Alpha and Beta Regio. [[note]]These features were first detected by ground-based radar in the mid-1960's; Alpha and Beta Regio were the first two terrain features to be isolated, and Maxwell Montes was named after James Clerk Maxwell, the formulator of the theory and equations of electromagnetism that ultimately led to the invention of radar.[[/note]] There is some argument over whether the proper adjective is "Venusian", "Venerean", or "Cytherean" — just don't use "Venereal".[[note]]Technically, the scientifically accepted demonym/adjective is "Cytherean", because "Venerean" sounds too similar to "Venereal", "Aphrodisial" sounds too similar to "Aphrodisiac", and "Venusian" is poor grammar — akin to "Earthian" or "Jupiterian" (The correct demonyms being, respectively, "Terrestrial" and "Jovian"). In practice, the most commonly used adjective is "Venusian".[[/note]]

Much of Venus' surface was shaped by extensive volcanism in its past. Over 90% of its surface is covered in basalt which would actually make the planet beneath the atmospheric veil appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, none of them are currently active, and none have been observed to have erupted recently --[[https://phys.org/news/2017-05-mystery-rare-volcanoes-venus.html explanations]] include that the intense heat causes the Venusian crust to be soft compared to Earth's one and lava gets stuck on it having difficulties to reach the surface. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons. With Venus' hellish conditions, getting a seismometer on the surface to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off. It does not help either that unlike for both Mars and the Moon, there're no meteorites[[note]]Rocks sent to space after a [[ColonyDrop asteroid impact]] powerful enough to overtake their gravities[[/note]] known to have come from Venus.

Virtually no close-up image of Venus you have ever seen or will ever see is real. Especially not [[https://media.wired.com/photos/5e59ad2b79c7100008eb6ae8/master/w_1600%2Cc_limit/photo_space_venus_1_S91-50688.jpg this one]]. That isn't even a true image of Venus with its clouds off, but has been colorised to bring out detail. In reality, Venus's surface would resemble a global volcanic lava field, and at that scale would be flat black. Even images of Venus with its clouds still on are usually wrong. Venus actually looks [[http://planetary.s3.amazonaws.com/image/3447783055_7201387b94_o.png like this]]; but it's easy to see why that image isn't widely circulated. Any layman glancing at it would [[RealityIsUnrealistic just assume it was black and white]].

Virtually no image of Venus you will ever see is real. Especially not [[https://media.wired.com/photos/5e59ad2b79c7100008eb6ae8/master/w_1600%2Cc_limit/photo_space_venus_1_S91-50688.jpg this one]]. That isn't even a true image of Venus with its clouds off, but has been colorised to bring out detail. In reality, Venus's surface would resemble a global volcanic lava field, and at that scale would be flat black. Even images of Venus with its clouds still on are usually wrong. Venus actually looks [[http://planetary.s3.amazonaws.com/image/3447783055_7201387b94_o.png like this]]; but it's easy to see why that image isn't widely circulated. Any layman glancing at it would [[RealityIsUnrealistic just assume it was black and white]].

* ''Old Venus'' is an anthology of short stories written in Pre-''Venera'' style, but by 21st century authors.

These rather depressing details were revealed by the Soviet ''Venera'' space probes, sent to the planet in the late 1960s. Before that time, many ScienceFiction authors held out hope that Venus might harbor life. Such hope was flimsy at best even before the ''Venera'' space probes, though; as early as the 1890s, spectrographs of the Cytherean atmosphere showed it to be made almost entirely of carbon dioxide, with ''no'' water vapor at all (meaning the clouds ''could not'' have been water clouds like those on Earth). Not to mention that Venus has no moon; Earth's own Moon (which is unusually large in proportion to the planet) is well known to be essential to Earth's habitability.[[note]]Given its similar size to Earth and that planetary collisions are thought to have been rather common during the formation of the solar system, the fact that Venus has no moon is somewhat surprising. This has led to the hypothesis that Venus ''used'' to have a moon, but it was destroyed by yet another impact event, possibly the same one that caused Venus's "backwards" rotation.[[/note]] Although the the top of the cloud layer was relatively cool, in 1962 the ''Mariner 2'' probe revealed that the surface was several hundred degrees Celsius.

* In ''ComicStrip/SafeHavens'' [[OurMermaidsAreDifferent mermaids]] actually originated from Venus. They came to Earth when Venus began undergoing its uninhabitable climate change, and modern merfolk descend from those left behind when the rest left after deciding Earth was too dangerous.

Much of Venus' surface was shaped by extensive volcanism in its past. Over 90% of its surface is covered in basalt which would actually make the planet beneath the atmospheric veil appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, none of them are currently active, and none have been observed to have erupted recently --[[https://phys.org/news/2017-05-mystery-rare-volcanoes-venus.html explanations]] include that the intense heat causes the Venusian crust to be soft compared to Earth's one and lava gets stuck on it having difficulties to reach the surface. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons. With Venus' hellish conditions, getting a seismometer on the surface to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off. It does not help either that unlike for both Mars and the Moon, those being rocks sent to space after a [[ColonyDrop asteroid impact]] powerful enough, there're no meteorites known to have come from Venus.

Much of Venus' surface was shaped by extensive volcanism in its past. Over 90% of its surface is covered in basalt which would actually make the planet beneath the atmospheric veil appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, none of them are currently active, and none have been observed to have erupted recently --[[https://phys.org/news/2017-05-mystery-rare-volcanoes-venus.html explanations]] include that the intense heat causes the Venusian crust to be soft compared to Earth's one and lava gets stuck on it having difficulties to reach the surface. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons. With Venus' hellish conditions, getting a seismometer on the surface to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off. It does not help either that unlike Mars or the Moon, them being rocks sent to space after a [[ColonyDrop powerful asteroid impact]], there're no meteorites known to have come from Venus.

Much of Venus' surface was shaped by extensive volcanism in its past. Over 90% of its surface is covered in basalt which would actually make the planet beneath the atmospheric veil appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, none of them are currently active, and none have been observed to have erupted recently. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons. With Venus' hellish conditions, getting a seismometer on the surface to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off.

Its surface features, long hidden under the constant cloud cover, were finally mapped by the ''Magellan'' space probe using radar in [[TheNineties the 1990s]]. The highest mountain is Maxwell Montes, almost 11 kilometres above the average surface level. If you stood on its peak, it'd be a downright chilly 380°C[[labelnote:*]]716°F[[/labelnote]], and a mere 60 atmospheres of pressure. The culprit for all this heat is the greenhouse effect — Earth's atmosphere is less than 1% carbon dioxide, while Venus's is over 90% carbon dioxide. Earth started with the same amount, [[SealedEvilInACan but it ended up trapped in carbonate rock]]. Venus also started with the same amount of water as the Earth had, but it remained in vapor form (300 atmospheres worth) and created [[UpToEleven a super greenhouse effect]] with temperatures in the ''thousands'' of degrees. [[note]]This plus the slow rotation probably wrecked any chance at plate tectonics; instead of plates constantly sliding against each other, [[LethalLavaLand there seems to be intermittent planet-wide volcanism wiping out many of the planet's surface features every billion years or so]]. [[http://adsabs.harvard.edu/abs/2001Icar..150...19B Some estimations]] suggest said events can cold ''a bit'' the planet, just to be later warmed up to 600°C (1160°F) before going back to those 500°C (900°F). And remember that as the Sun ages it's more luminous, so remperatures can only go up[[/note]] Eventually the water molecules dissociated into hydrogen and oxygen and escaped into space and sank down and fused with the rocks respectively, leaving Venus high and dry. Due to Venus being mythologically associated with femininity, by convention all geographic features there are named after women or female entities, except for Maxwell Montes and Alpha and Beta Regio. [[note]]These features were first detected by ground-based radar in the mid-1960's; Alpha and Beta Regio were the first two terrain features to be isolated, and Maxwell Montes was named after James Clerk Maxwell, the formulator of the theory and equations of electromagnetism that ultimately led to the invention of radar.[[/note]] There is some argument over whether the proper adjective is "Venusian", "Venerean", or "Cytherean" — just don't use "Venereal".[[note]]Technically, the scientifically accepted demonym/adjective is "Cytherean", because "Venerean" sounds too similar to "Venereal", "Aphrodisial" sounds too similar to "Aphrodisiac", and "Venusian" is poor grammar — akin to "Earthian" or "Jupiterian" (The correct demonyms being, respectively, "Terrestrial" and "Jovian"). In practice, the most commonly used adjective is "Venusian".[[/note]]

Venus has the slowest rotation out of any planet in the Solar System, and it rotates in a clockwise direction relative to the other planets (meaning it spins backwards). It's not entirely understood why the planet came to be with such an unusual rotation, but one of the theories is that at some point in the planet's early history, a planetesimal struck it at an oblique angle, causing it to rotate very slowly backwards. However, this theory is contested because of the lack of geological evidence on the planet's surface. If such an event did happen, the global resurfacing event some 500-300 million years ago likely erased the evidence. Another more plausible theory is that Venus' original counterclockwise rotation gradually slowed because of tidal interactions with the Sun, but its dense atmosphere created an equilibrium effect to prevent it from becoming tidally locked, hence the reverse rotation. As a result of this super-slow rotation, a Cytherean solar day is longer than a Venusian year (Venus' year is 225 Earth days, its day is 243 Earth days). Not that you'd be able to ''see'' much difference between day and night while on the surface. Whether you're on the day side or the night side, you'll see a hazy overcast sky that's about the same brightness everywhere — assuming you survive the lack of oxygen, the crushing pressures, and the hellish temperatures, that is[[note]]Day surface levels of light are similar to a cloudcast day on Earth, and it has been calculated that [[https://www.reddit.com/r/askscience/comments/4y2331/is_visibility_much_worse_in_venuss_atmosphere/ visibility levels would be up to 3 kilometers]]. In addition to this, [[http://space.stackexchange.com/questions/2237/how-long-will-it-be-light-on-venus-at-night the refraction of the Venusian atmosphere is so high]] that it would look as if you was in a basin/valley (calculations show too that at a height of 35 kilometers you'd be able to see ''the entire planet'' (read: clouds) in a panoramic view). Down on Venus' surface objects dropped to the ground would very slowly fall due to the atmosphere's density (50 times more than Earth's one, or 6.5% of water's density), moving would rather be similar to swimming, and winds while having breeze-like speeds would have hurricane-like strength for the same reasons. Meanwhile, the sky would just show a faint sliver of light where the Sun was located, and on the night side besides lightning and active volcanoes illuminating the clouds you'd be able to see rocks glowing with a very faint red color due to the searing hot temperature. Have fun while you're there (And have we mentioned Venus is very often compared to [[FireAndBrimstoneHell Hell]]?)[[/note]]. This slow rotation is also responsible for the current state of Venus's atmosphere. Venus rotates far too slowly to produce a strong magnetic field, leaving the water vapor that was once in its atmosphere vulnerable to dissociation by solar radiation. If circumstances had left Venus rotating at a similar rate to Earth, its magnetic field would be nearly as strong, and then who knows what the planet would be like.

Also unique to Venus is that many of its volcanic features take on unusual shapes that are not seen elsewhere in the Solar System. The most common of these are shield volcanoes that form flat, pancake-like dome structures called "farra", and they can be anywhere between 10 times to 100 times larger than shield volcanoes on Earth. Another common feature are web-like structures appropriately called "arachnoids" due to the fact that they resemble spider webs, and they can stretch for hundreds of kilometers in either direction. It's unknown how these features have formed in the first place.

Much of Venus' surface is shaped by extensive volcanism. Over 90% of its surface is covered in basalt which would actually make the planet beneath the atmospheric veil appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, they're not currently active, and none have been observed to have erupted recently. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons. With Venus' hellish conditions, getting a seismometer to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off.

Much of Venus' surface is shaped by extensive volcanism. Over 90% of its surface is covered in basalt which would actually make the planet appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, they're not currently active, and none have been observed to have erupted recently. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons. With Venus' hellish conditions, getting a seismometer to accurately measure Venus' interior much like Mars' ''[=InSight=]'' mission would be incredibly difficult to pull off.

Much of Venus' surface is shaped by extensive volcanism. Over 90% of its surface is covered in basalt which would actually make the planet appear black from our eyes,[[note]]The reason the Magellan radar maps appear yellow is simply an artistic decision on the scientists' behalf based on the planet's atmosphere.[[/note]] and 65% of the planet consists of relatively flat lava plains with a few highland regions that stand out. Over 1,000 volcanoes have been identified, making Venus the planet with the most volcanoes in the Solar System. However, they're not currently active, and none have been observed to have erupted recently. The state of Venus' core and whether it is geologically active is rather ambiguous since unlike UsefulNotes/TheMoon, UsefulNotes/{{Mercury}} and UsefulNotes/{{Mars}} (which are all definitively considered dead), Venus' similar size to Earth should mean that it should still be geologically active today. But what throws a wrench in this theory is Venus' lack of plate tectonics and a magnetic field, which could also indicate that Venus may be geologically dead. So far, the only evidence that supports active volcanism on Venus is the high concentration of sulfur dioxide in its atmosphere as well as infrared hot spots observed around Maat Mons. With Venus' hellish conditions, getting a seismometer to accurately measure Venus' interior much like Mars' [=InSight=] mission would be incredibly difficult to pull off.

Venus has the slowest rotation out of any planet in the solar system, and it rotates in a clockwise direction relative to the other planets (meaning it spins backwards). It's not entirely understood why the planet came to be with such an unusual rotation, but one of the theories is that at some point in the planet's early history, a planetesimal struck it at an oblique angle, causing it to rotate very slowly backwards. However, this theory is contested because of the lack of geological evidence on the planet's surface. If such an event did happen, the global resurfacing event some 500-300 million years ago likely erased the evidence. Another more plausible theory is that Venus' original counterclockwise rotation gradually slowed because of tidal interactions with the Sun, but its dense atmosphere created an equilibrium effect to prevent it from becoming tidally locked, hence the reverse rotation. As a result of this super-slow rotation, a Cytherean solar day is longer than a Venusian year (Venus' year is 225 Earth days, its day is 243 Earth days). Not that you'd be able to ''see'' much difference between day and night while on the surface. Whether you're on the day side or the night side, you'll see a hazy overcast sky that's about the same brightness everywhere — assuming you survive the lack of oxygen, the crushing pressures, and the hellish temperatures, that is[[note]]Day surface levels of light are similar to a cloudcast day on Earth, and it has been calculated that [[https://www.reddit.com/r/askscience/comments/4y2331/is_visibility_much_worse_in_venuss_atmosphere/ visibility levels would be up to 3 kilometers]]. In addition to this, [[http://space.stackexchange.com/questions/2237/how-long-will-it-be-light-on-venus-at-night the refraction of the Venusian atmosphere is so high]] that it would look as if you was in a basin/valley (calculations show too that at a height of 35 kilometers you'd be able to see ''the entire planet'' (read: clouds) in a panoramic view). Down on Venus' surface objects dropped to the ground would very slowly fall due to the atmosphere's density (50 times more than Earth's one, or 6.5% of water's density), moving would rather be similar to swimming, and winds while having breeze-like speeds would have hurricane-like strength for the same reasons. Meanwhile, the sky would just show a faint sliver of light where the Sun was located, and on the night side besides lightning and active volcanoes illuminating the clouds you'd be able to see rocks glowing with a very faint red color due to the searing hot temperature. Have fun while you're there (And have we mentioned Venus is very often compared to [[FireAndBrimstoneHell Hell]]?)[[/note]]. This slow rotation is also responsible for the current state of Venus's atmosphere. Venus rotates far too slowly to produce a strong magnetic field, leaving the water vapor that was once in its atmosphere vulnerable to dissociation by solar radiation. If circumstances had left Venus rotating at a similar rate to Earth, its magnetic field would be nearly as strong, and then who knows what the planet would be like.