This article is about the planet. For the deity, see Venus (mythology).

For other uses, see Venus

(disambiguation).

Venus

True colour Venus, captured by MESSENGER

Designations

/ˈviːnəs/ ⓘ
Pronunciation

Named after Roman goddess of love (see goddess

Venus)

Adjectives Venusian /vɪˈnjuːziən, -ʒən/,[1] rarely Cy

therean /sɪθəˈriːən/[2] or Venerean /

Venerian /vɪˈnɪəriən/[3]

Symbol

Orbital characteristics[4][5]

Epoch J2000

Aphelion 0.728213 AU (108.94 million km)

Perihelion 0.718440 AU (107.48 million km)

Semi-major axis 0.723332 AU (108.21 million km)

Eccentricity 0.006772[6]

Orbital period  224.701 d[4]

(sidereal)
  0.615198 yr

 1.92 Venus solar day

Orbital period 583.92 days[4]

(synodic)

Average orbital speed 35.02 km/s

Mean anomaly 50.115°

Inclination  3.39458° to ecliptic

 3.86° to Sun's equator

 2.15° to invariable plane[7]

Longitude of 76.680°[6]
ascending node

Argument of 54.884°
perihelion

Satellites None

Physical characteristics

Mean radius  6,051.8±1.0 km[8]

 0.9499 Earths

Flattening 0[8]

Surface area  4.6023×108 km2

 0.902 Earths

Volume  9.2843×1011 km3

 0.857 Earths

Mass  4.8675×1024 kg[9]

 0.815 Earths

Mean density 5.243 g/cm3

Surface gravity  8.87 m/s2

 0.904 g

Escape velocity 10.36 km/s (6.44 mi/s)[10]

Synodic rotation −116.75 d (retrograde)[11]

period
1 Venus solar day

Sidereal rotation −243.0226 d (retrograde)[12]

period

Equatorial 6.52 km/h (1.81 m/s)

rotation velocity

Axial tilt 2.64° (for retrograde rotation)

 177.36° (to orbit)[4][note 1]

North pole right  18h 11m 2s

ascension
 272.76°[13]

North pole declination 67.16°

Albedo  0.689 (geometric)[14]

 0.76 (Bond)[15]

Temperature 232 K (−41 °C) (blackbody

temperature)[16]

Surface temp. min mean max

Kelvin 737 K[4]
Celsius 464 °C
Fahrenheit 867 °F

Surface absorbed 2.1×10−6 μGy/h[17]

dose rate

Surface equivalent 2.2×10−6 μSv/h

dose rate 0.092–22 μSv/h at cloud level[17]

Apparent magnitude −4.92 to −2.98[18]

Absolute −4.4[19]
magnitude (H)

Angular diameter 9.7″–66.0″[4]

Atmosphere[4]

Surface pressure 93 bar (9.3 MPa)

92 atm

Composition by  96.5% carbon dioxide

volume  3.5% nitrogen

 0.015% sulphur dioxide

 0.0070% argon

 0.0020% water vapour

 0.0017% carbon monoxide

 0.0012% helium

 0.0007% neon

 Trace carbonyl sulfide

 Trace hydrogen chloride

 Trace hydrogen fluoride

1. ^ Defining the rotation as retrograde, as done by

 NASA space missions and the USGS,

puts Ishtar Terra in the northern hemisphere and

makes the axial tilt 2.64°. Following the right-

hand rule for prograde rotation puts Ishtar Terra

in the negative hemisphere and makes the axial

tilt 177.36°.

Venus is the second planet from the Sun. It is a rocky planet and is the closest in mass and
size to its orbital neighbour Earth. Venus is notable for its very thick carbon dioxide atmosphere
and a sulfuric acid cloud cover. At the surface, Venusian atmosphere has a mean temperature of
737 K (464 °C; 867 °F) and a pressure of 92 times that of Earth's at sea level. This makes Venus
having the densest atmosphere of all the rocky bodies in the Solar System, so dense that carbon
dioxide is compressed into a supercritical state.
Internally, Venus has a core, mantle, and crust. Internal heat escapes through active volcanism,
resulting in resurfacing instead of plate tectonics. Venus is one of two planets in the Solar
System that have no moons.[20] Conditions perhaps favourable for life on Venus have been
identified at its cloud layers. Venus may have had liquid surface water early in its history with
a habitable environment,[21][22] but runaway greenhouse effects has evaporated any water and
turned Venus into an igneous world.[23][24][25]
The rotation of Venus has been slowed and turned against its orbital direction (retrograde) by the
strong currents and drag of its atmosphere. It takes 224.7 Earth days for Venus to complete an
orbit around the Sun, and a Venusian solar year is just under two Venusian days long. The orbits
of Venus and Earth are the closest between any two Solar System planets, approaching each
other in synodic periods of 1.6 years. Venus and Earth have the lowest difference in gravitational
potential of any pair of Solar System planets. This allows Venus to be the
most accessible destination and a useful gravity assist waypoint for interplanetary flights from
Earth.
Venus has historically been a common and important object for humans, in both their
cultures and astronomy. Orbiting inferiorly (inside of Earth's orbit), it always appears close to the
Sun in Earth's sky, as either a "morning star" or an "evening star". While this is also true
for Mercury, Venus appears more prominent, since it is the third brightest object in Earth's
sky after the Moon and the Sun.[26][27]
In 1961, Venus became the target of the first interplanetary flight, Venera 1, followed by many
essential interplanetary firsts, such as the first soft landing on another planet by Venera 7 in
1970. These probes demonstrated the extreme surface conditions, an insight that has informed
predictions about global warming on Earth.[28][29] This finding ended the theories and then
popular science fiction about Venus being a habitable or inhabited planet.

Physical characteristics

Venus to scale among the terrestrial planets of the Solar

System, which are arranged by the order of their Inner Solar System orbits outward from the
Sun (from left: Mercury, Venus, Earth and Mars)
Venus is one of the four terrestrial planets in the Solar System, meaning that it is a rocky body
like Earth. It is similar to Earth in size and mass and is often described as Earth's "sister" or
"twin".[30] Venus is close to spherical due to its slow rotation.[31] Venus has a diameter of
12,103.6 km (7,520.8 mi)—only 638.4 km (396.7 mi) less than Earth's—and its mass is 81.5% of
Earth's, making it the third-smallest planet overall. Conditions on the Venusian surface differ
radically from those on Earth because its dense atmosphere is 96.5% carbon dioxide, with most
of the remaining 3.5% being nitrogen.[32] The surface pressure is 9.3 megapascals (93 bars), and
the average surface temperature is 737 K (464 °C; 867 °F), above the critical points of both
major constituents and making the surface atmosphere a supercritical fluid out of
mainly supercritical carbon dioxide and some supercritical nitrogen.
Atmosphere and climate
Main article: Atmosphere of Venus

Cloud structure of the Venusian atmosphere, made visible

through ultraviolet imaging
Venus has a dense atmosphere composed of 96.5% carbon dioxide, 3.5% nitrogen—both exist
as supercritical fluids at the planet's surface with a density 6.5% that of water [33]—and traces of
other gases including sulphur dioxide.[34] The mass of its atmosphere is 92 times that of Earth's,
whereas the pressure at its surface is about 93 times that at Earth's—a pressure equivalent to
that at a depth of nearly 1 km (5⁄8 mi) under Earth's ocean surfaces. The density at the surface is
65 kg/m3 (4.1 lb/cu ft), 6.5% that of water[33] or 50 times as dense as Earth's atmosphere at 293 K
(20 °C; 68 °F) at sea level. The CO2-rich atmosphere generates the strongest greenhouse
effect in the Solar System, creating surface temperatures of at least 735 K (462 °C; 864 °F).[35]
[36]
This makes the Venusian surface hotter than Mercury's, which has a minimum surface
temperature of 53 K (−220 °C; −364 °F) and maximum surface temperature of 700 K (427 °C;
801 °F),[37][38] even though Venus is nearly twice Mercury's distance from the Sun and thus
receives only 25% of Mercury's solar irradiance. Because of its runaway greenhouse effect,
Venus has been identified by scientists such as Carl Sagan as a warning and research object
linked to climate change on Earth.[28][29]
Venus temperature[39]

Surface
Type
temperature

Maximum 900 °F (482 °C)

Normal 847 °F (453 °C)

Minimum 820 °F (438 °C)

Venus's atmosphere is rich in primordial noble gases compared to that of Earth.[40] This
enrichment indicates an early divergence from Earth in evolution. An unusually large comet
impact[41] or accretion of a more massive primary atmosphere from solar nebula[42] have been
proposed to explain the enrichment. However, the atmosphere is depleted of radiogenic argon, a
proxy for mantle degassing, suggesting an early shutdown of major magmatism.[43][44]
Studies have suggested that billions of years ago, Venus's atmosphere could have been much
more like the one surrounding the early Earth, and that there may have been substantial
quantities of liquid water on the surface.[45][46][47] After a period of 600 million to several billion years,
[48]
solar forcing from rising luminosity of the Sun and possibly large volcanic resurfacing caused
the evaporation of the original water and the current atmosphere.[49] A runaway greenhouse effect
was created once a critical level of greenhouse gases (including water) was added to its
atmosphere.[50] Although the surface conditions on Venus are no longer hospitable to any Earth-
like life that may have formed before this event, there is speculation on the possibility that life
exists in the upper cloud layers of Venus, 50 km (30 mi) up from the surface, where the
atmospheric conditions are the most Earth-like in the Solar System,[51] with temperatures ranging
between 303 and 353 K (30 and 80 °C; 86 and 176 °F), and the pressure and radiation being
about the same as at Earth's surface, but with acidic clouds and the carbon dioxide air. [52][53][54] The
putative detection of an absorption line of phosphine in Venus's atmosphere, with no known
pathway for abiotic production, led to speculation in September 2020 that there could be extant
life currently present in the atmosphere.[55][56] Later research attributed the spectroscopic signal
that was interpreted as phosphine to sulphur dioxide,[57] or found that in fact there was no
absorption line.[58][59]

Types of cloud layers, as well as temperature and pressure

change by altitude in the atmosphere
Thermal inertia and the transfer of heat by winds in the lower atmosphere mean that the
temperature of Venus's surface does not vary significantly between the planet's two
hemispheres, those facing and not facing the Sun, despite Venus's slow rotation. Winds at the
surface are 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
transport dust and small stones across the surface. This alone would make it difficult for a human
to walk through, even without the heat, pressure, and lack of oxygen. [60]
Above the dense CO2 layer are thick clouds, consisting mainly of sulfuric acid, which is formed by
sulphur dioxide and water through a chemical reaction resulting in sulfuric acid hydrate.
Additionally, the clouds consist of approximately 1% ferric chloride.[61][62] Other possible
constituents of the cloud particles are ferric sulfate, aluminium chloride and phosphoric
anhydride. Clouds at different levels have different compositions and particle size distributions.
[61]
These clouds reflect, similar to thick cloud cover on Earth,[63] about 70% of the sunlight that falls
on them back into space,[64] and since they cover the whole planet they prevent visual observation
of Venus's surface. The permanent cloud cover means that although Venus is closer than Earth
to the Sun, it receives less sunlight on the ground, with only 10% of the received sunlight
reaching the surface,[65] resulting in average daytime levels of illumination at the surface of
14,000 lux, comparable to that on Earth "in the daytime with overcast clouds". [66] Strong 300 km/h
(185 mph) winds at the cloud tops go around Venus about every four to five Earth days. [67] Winds
on Venus move at up to 60 times the speed of its rotation, whereas Earth's fastest winds are only
10–20% rotation speed.[68]
The surface of Venus is effectively isothermal; it retains a constant temperature not only between
the two hemispheres but between the equator and the poles.[4][69] Venus's minute axial tilt—less
than 3°, compared to 23° on Earth—also minimises seasonal temperature variation. [70] Altitude is
one of the few factors that affect Venusian temperatures. The highest point on Venus, Maxwell
Montes, is therefore the coolest point on Venus, with a temperature of about 655 K (380 °C;
715 °F) and an atmospheric pressure of about 4.5 MPa (45 bar).[71][72] In 1995,
the Magellan spacecraft imaged a highly reflective substance at the tops of the highest mountain
peaks, a "Venus snow" that bore a strong resemblance to terrestrial snow. This substance likely
formed from a similar process to snow, albeit at a far higher temperature. Too volatile to
condense on the surface, it rose in gaseous form to higher elevations, where it is cooler and
could precipitate. The identity of this substance is not known with certainty, but speculation has
ranged from elemental tellurium to lead sulfide (galena).[73]
Although Venus has no seasons, in 2019 astronomers identified a cyclical variation in sunlight
absorption by the atmosphere, possibly caused by opaque, absorbing particles suspended in the
upper clouds. The variation causes observed changes in the speed of Venus's zonal winds and
appears to rise and fall in time with the Sun's 11-year sunspot cycle.[74]
The existence of lightning in the atmosphere of Venus has been controversial [75] since the first
suspected bursts were detected by the Soviet Venera probes.[76][77][78] In 2006–07, Venus
Express clearly detected whistler mode waves, the signatures of lightning.
Their intermittent appearance indicates a pattern associated with weather activity. According to
these measurements, the lightning rate is at least half that on Earth, [79] however other instruments
have not detected lightning at all.[75] The origin of any lightning remains unclear, but could
originate from clouds or Venusian volcanoes.
In 2007, Venus Express discovered that a huge double atmospheric polar vortex exists at the
south pole.[80][81] Venus Express discovered, in 2011, that an ozone layer exists high in the
atmosphere of Venus.[82] On 29 January 2013, ESA scientists reported that the ionosphere of
Venus streams outwards in a manner similar to "the ion tail seen streaming from a comet under
similar conditions."[83][84]
In December 2015, and to a lesser extent in April and May 2016, researchers working on
Japan's Akatsuki mission observed bow-shaped objects in the atmosphere of Venus. This was
considered direct evidence of the existence of perhaps the largest stationary gravity waves in the
solar system.[85][86][87]
Geography
Main articles: Geology of Venus, Geodynamics of Venus, Mapping of Venus, and Surface
features of Venus

Color-coded elevation map, showing the

elevated terrae "continents" in yellow and minor features of Venus.
The Venusian surface was a subject of speculation until some of its secrets were revealed
by planetary science in the 20th century. Venera landers in 1975 and 1982 returned images of a
surface covered in sediment and relatively angular rocks.[88] The surface was mapped in detail
by Magellan in 1990–91. The ground shows evidence of extensive volcanism, and the sulphur in
the atmosphere may indicate that there have been recent eruptions. [89][90]
About 80% of the Venusian surface is covered by smooth, volcanic plains, consisting of 70%
plains with wrinkle ridges and 10% smooth or lobate plains.[91] Two highland "continents" make up
the rest of its surface area, one lying in the planet's northern hemisphere and the other just south
of the equator. The northern continent is called Ishtar Terra after Ishtar, the Babylonian goddess
of love, and is about the size of Australia. Maxwell Montes, the highest mountain on Venus, lies
on Ishtar Terra. Its peak is 11 km (7 mi) above the Venusian average surface elevation.[92] The
southern continent is called Aphrodite Terra, after the Greek mythological goddess of love, and is
the larger of the two highland regions at roughly the size of South America. A network of
fractures and faults covers much of this area.[93]
The absence of evidence of lava flow accompanying any of the visible calderas remains an
enigma. The planet has few impact craters, demonstrating that the surface is relatively young, at
300–600 million years old.[94][95] Venus has some unique surface features in addition to the impact
craters, mountains, and valleys commonly found on rocky planets. Among these are flat-topped
volcanic features called "farra", which look somewhat like pancakes and range in size from 20 to
50 km (12 to 31 mi) across, and from 100 to 1,000 m (330 to 3,280 ft) high; radial, star-like
fracture systems called "novae"; features with both radial and concentric fractures resembling
spider webs, known as "arachnoids"; and "coronae", circular rings of fractures sometimes
surrounded by a depression. These features are volcanic in origin.[96]
Most Venusian surface features are named after historical and mythological women.
[97]
Exceptions are Maxwell Montes, named after James Clerk Maxwell, and highland
regions Alpha Regio, Beta Regio, and Ovda Regio. The last three features were named before
the current system was adopted by the International Astronomical Union, the body which
oversees planetary nomenclature.[98]
The longitude of physical features on Venus is expressed relative to its prime meridian. The
original prime meridian passed through the radar-bright spot at the centre of the oval feature Eve,
located south of Alpha Regio.[99] After the Venera missions were completed, the prime meridian
was redefined to pass through the central peak in the crater Ariadne on Sedna Planitia.[100][101]
The stratigraphically oldest tessera terrains have consistently lower thermal emissivity than the
surrounding basaltic plains measured by Venus Express and Magellan, indicating a different,
possibly a more felsic, mineral assemblage.[24][102] The mechanism to generate a large amount of
felsic crust usually requires the presence of water ocean and plate tectonics, implying that
habitable condition had existed on early Venus with large bodies of water at some point.
[103]
However, the nature of tessera terrains is far from certain.[104]
Studies reported on 26 October 2023 suggest for the first time that Venus may have had plate
tectonics during ancient times and, as a result, may have had a more habitable environment,
possibly one capable of sustaining life.[21][22] Venus has gained interest as a case for research into
the development of Earth-like planets and their habitability.

180-degree panorama of Venus's surface from the Soviet Venera 9 lander, 1975. Black-and-
white image of barren, black, slate-like rocks against a flat sky. The ground and the probe are
the focus.
Volcanism
Main article: Volcanism on Venus
 Radar mosaic of two 65 km (40 mi) wide (and less than
1 km (0.62 mi) high) pancake domes in Venus's Eistla region
Much of the Venusian surface appears to have been shaped by volcanic activity. Venus has
several times as many volcanoes as Earth, and it has 167 large volcanoes that are over 100 km
(60 mi) across. The only volcanic complex of this size on Earth is the Big Island of Hawaii.[96]:
154
More than 85,000 volcanoes on Venus were identified and mapped.[105][106] This is not because
Venus is more volcanically active than Earth, but because its crust is older and is not subject to
the same erosion process. Earth's oceanic crust is continually recycled by subduction at the
boundaries of tectonic plates, and has an average age of about 100 million years, [107] whereas the
Venusian surface is estimated to be 300–600 million years old.[94][96]
Several lines of evidence point to ongoing volcanic activity on Venus. Sulfur dioxide
concentrations in the upper atmosphere dropped by a factor of 10 between 1978 and 1986,
jumped in 2006, and again declined 10-fold.[108] This may mean that levels had been boosted
several times by large volcanic eruptions.[109][110] It has been suggested that Venusian lightning
(discussed below) could originate from volcanic activity (i.e. volcanic lightning). In January 2020,
astronomers reported evidence that suggests that Venus is currently volcanically active,
specifically the detection of olivine, a volcanic product that would weather quickly on the planet's
surface.[111][112]
This massive volcanic activity is fuelled by a superheated interior, which models say could be
explained by energetic collisions from when the planet was young. Impacts would have had
significantly higher velocity than on Earth, both because Venus's orbit is faster due to its closer
proximity to the Sun and because objects would require higher orbital eccentricities to collide with
the planet.[113]
In 2008 and 2009, the first direct evidence for ongoing volcanism was observed by Venus
Express, in the form of four transient localized infrared hot spots within the rift zone Ganis
Chasma,[114][note 1] near the shield volcano Maat Mons. Three of the spots were observed in more
than one successive orbit. These spots are thought to represent lava freshly released by volcanic
eruptions.[115][116] The actual temperatures are not known, because the size of the hot spots could
not be measured, but are likely to have been in the 800–1,100 K (527–827 °C; 980–1,520 °F)
range, relative to a normal temperature of 740 K (467 °C; 872 °F).[117] In 2023, scientists
reexamined topographical images of the Maat Mons region taken by the Magellan orbiter. Using
computer simulations, they determined that the topography had changed during an 8-month
interval, and concluded that active volcanism was the cause.[118]
Craters

Impact craters on the surface of Venus (false-colour image

reconstructed from radar data)
Almost a thousand impact craters on Venus are evenly distributed across its surface. On other
cratered bodies, such as Earth and the Moon, craters show a range of states of degradation. On
the Moon, degradation is caused by subsequent impacts, whereas on Earth it is caused by wind
and rain erosion. On Venus, about 85% of the craters are in pristine condition. The number of
craters, together with their well-preserved condition, indicates the planet underwent a global
resurfacing event 300–600 million years ago,[94][95] followed by a decay in volcanism.[119] Whereas
Earth's crust is in continuous motion, Venus is thought to be unable to sustain such a process.
Without plate tectonics to dissipate heat from its mantle, Venus instead undergoes a cyclical
process in which mantle temperatures rise until they reach a critical level that weakens the crust.
Then, over a period of about 100 million years, subduction occurs on an enormous scale,
completely recycling the crust.[96]
Venusian craters range from 3 to 280 km (2 to 174 mi) 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 so much by the atmosphere that they do not create an
impact crater.[120] Incoming projectiles less than 50 m (160 ft) in diameter will fragment and burn
up in the atmosphere before reaching the ground.[121]
Internal structure

The differentiated structure of Venus

Without data from reflection seismology or knowledge of its moment of inertia, little direct
information is available about the internal structure and geochemistry of Venus.[122] The similarity
in size and density between Venus and Earth suggests that they share a similar internal
structure: a core, mantle, and crust. Like that of Earth, the Venusian core is most likely at least
partially liquid because the two planets have been cooling at about the same rate, [123] although a
completely solid core cannot be ruled out.[124] The slightly smaller size of Venus means pressures
are 24% lower in its deep interior than Earth's.[125] The predicted values for the moment of inertia
based on planetary models suggest a core radius of 2,900–3,450 km.[124] This is in line with the
first observation-based estimate of 3,500 km.[126]
The principal difference between the two planets is the lack of evidence for plate tectonics on
Venus, possibly because its crust is too strong to subduct without water to make it less viscous.
This results in reduced heat loss from the planet, preventing it from cooling and providing a likely
explanation for its lack of an internally generated magnetic field.[127] Instead, Venus may lose its
internal heat in periodic major resurfacing events.[94]
Magnetic field and core
In 1967, Venera 4 found Venus's magnetic field to be much weaker than that of Earth. This
magnetic field is induced by an interaction between the ionosphere and the solar wind,[128][129]
[page needed]
rather than by an internal dynamo as in the Earth's core. Venus's small induced
magnetosphere provides negligible protection to the atmosphere against solar and cosmic
radiation, reaching at elevations of 54 to 48 km Earth-like levels.[clarification needed][130][131]
The lack of an intrinsic magnetic field on Venus was surprising, given that it is similar to Earth in
size and was expected to contain a dynamo at its core. A dynamo requires three things:
a conducting liquid, rotation, and convection. The core is thought to be electrically conductive
and, although its rotation is often thought to be too slow, simulations show it is adequate to
produce a dynamo.[132][133] This implies that the dynamo is missing because of a lack of convection
in Venus's core. On Earth, convection occurs in the liquid outer layer of the core because the
bottom of the liquid layer is much higher in temperature than the top. On Venus, a global
resurfacing event may have shut down plate tectonics and led to a reduced heat flux through the
crust. This insulating effect would cause the mantle temperature to increase, thereby reducing
the heat flux out of the core. As a result, no internal geodynamo is available to drive a magnetic
field. Instead, the heat from the core is reheating the crust.[134]
One possibility is that Venus has no solid inner core,[135] or that its core is not cooling, so that the
entire liquid part of the core is at approximately the same temperature. Another possibility is that
its core has already been completely solidified. The state of the core is highly dependant on the
concentration of sulphur, which is unknown at present.[134]
Another possibility is that the absence of a late, large impact on Venus (contra the Earth's
"Moon-forming" impact) left the core of Venus stratified from the core's incremental formation,
and without the forces to initiate/sustain convection, and thus a "geodynamo". [136]
The weak magnetosphere around Venus means that the solar wind is interacting directly with its
outer atmosphere. Here, ions of hydrogen and oxygen are being created by the dissociation of
water molecules from ultraviolet radiation. The solar wind then supplies energy that gives some
of these ions sufficient velocity to escape Venus's gravity field. This erosion process results in a
steady loss of low-mass hydrogen, helium, and oxygen ions, whereas higher-mass molecules,
such as carbon dioxide, are more likely to be retained. Atmospheric erosion by the solar wind
could have led to the loss of most of Venus's water during the first billion years after it formed.
[137]
However, the planet may have retained a dynamo for its first 2–3 billion years, so the water
loss may have occurred more recently.[138] The erosion has increased the ratio of higher-
mass deuterium to lower-mass hydrogen in the atmosphere 100 times compared to the rest of
the solar system.[139]

Orbit and rotation

Main article: Orbit of Venus

Venus is the second planet from the Sun, making a full

orbit in about 224 days
Venus orbits the Sun at an average distance of about 0.72 AU (108 million km; 67 million mi),
and completes an orbit every 224.7 days. Although all planetary orbits are elliptical, Venus's orbit
is currently the closest to circular, with an eccentricity of less than 0.01.[4] Simulations of the early
solar system orbital dynamics have shown that the eccentricity of the Venus orbit may have been
substantially larger in the past, reaching values as high as 0.31 and possibly impacting early
climate evolution.[140]

Venus and its rotation in respect to its revolution.

All planets in the Solar System orbit the Sun in an anticlockwise direction as viewed from above
Earth's north pole. Most planets rotate on their axes in an anticlockwise direction, but Venus
rotates clockwise in retrograde rotation once every 243 Earth days—the slowest rotation of any
planet. This Venusian sidereal day lasts therefore longer than a Venusian year (243 versus 224.7
Earth days). Slowed by its strong atmospheric current the length of the day also fluctuates by up
to 20 minutes.[141] Venus's equator rotates at 6.52 km/h (4.05 mph), whereas Earth's rotates at
1,674.4 km/h (1,040.4 mph).[note 2][145] Venus's rotation period measured with Magellan spacecraft
data over a 500-day period is smaller than the rotation period measured during the 16-year
period between the Magellan spacecraft and Venus Express visits, with a difference of about
6.5 minutes.[146] Because of the retrograde rotation, the length of a solar day on Venus is
significantly shorter than the sidereal day, at 116.75 Earth days (making the Venusian solar day
shorter than Mercury's 176 Earth days — the 116-day figure is close to the average number of
days it takes Mercury to slip underneath the Earth in its orbit [the number of days of Mercury's
synodic orbital period]).[11] One Venusian year is about 1.92 Venusian solar days.[147] To an
observer on the surface of Venus, the Sun would rise in the west and set in the east,[147] although
Venus's opaque clouds prevent observing the Sun from the planet's surface. [148]
Venus may have formed from the solar nebula with a different rotation period and obliquity,
reaching its current state because of chaotic spin changes caused by planetary perturbations
and tidal effects on its dense atmosphere, a change that would have occurred over the course of
billions of years. The rotation period of Venus may represent an equilibrium state between tidal
locking to the Sun's gravitation, which tends to slow rotation, and an atmospheric tide created by
solar heating of the thick Venusian atmosphere.[149][150] The 584-day average interval between
successive close approaches to Earth is almost exactly equal to 5 Venusian solar days
(5.001444 to be precise),[151] but the hypothesis of a spin-orbit resonance with Earth has been
discounted.[152]
Venus has no natural satellites.[153] It has several trojan asteroids: the quasi-satellite 524522
Zoozve[154][155] and two other temporary trojans, 2001 CK32 and 2012 XE133.[156] In the 17th
century, Giovanni Cassini reported a moon orbiting Venus, which was named Neith and
numerous sightings were reported over the following 200 years, but most were determined to be
stars in the vicinity. Alex Alemi's and David Stevenson's 2006 study of models of the early Solar
System at the California Institute of Technology shows Venus likely had at least one moon
created by a huge impact event billions of years ago.[157] About 10 million years later, according to
the study, another impact reversed the planet's spin direction and the resulting tidal
deceleration caused the Venusian moon gradually to spiral inward until it collided with Venus.
[158]
If later impacts created moons, these were removed in the same way. An alternative
explanation for the lack of satellites is the effect of strong solar tides, which can destabilize large
satellites orbiting the inner terrestrial planets.[153]
The orbital space of Venus has a dust ring-cloud,[159] with a suspected origin either from Venus–
trailing asteroids,[160] interplanetary dust migrating in waves, or the remains of the Solar System's
original circumstellar disc that formed the planetary system.[161]
Orbit in respect to Earth

Earth is positioned at the centre of the diagram, and the curve

represents the direction and distance of Venus as a function of time.
Earth and Venus have a near orbital resonance of 13:8 (Earth orbits eight times for every 13
orbits of Venus).[162] Therefore, they approach each other and reach inferior conjunction in synodic
periods of 584 days, on average.[4] The path that Venus makes in relation to Earth viewed
geocentrically draws a pentagram over five synodic periods, shifting every period by 144°. This
pentagram of Venus is sometimes referred to as the petals of Venus due to the path's visual
similarity to a flower.[163]
When Venus lies between Earth and the Sun in inferior conjunction, it makes the closest
approach to Earth of any planet at an average distance of 41 million km (25 million mi).[4][note 3]
[164]
Because of the decreasing eccentricity of Earth's orbit, the minimum distances will become
greater over tens of thousands of years. From the year 1 to 5383, there are 526 approaches less
than 40 million km (25 million mi); then, there are none for about 60,158 years.[165]
While Venus approaches Earth the closest, Mercury is more often the closest to Earth of all
planets.[166][167] Venus has the lowest gravitational potential difference to Earth than any other
planet, needing the lowest delta-v to transfer between them.[168][169]
Tidally Venus exerts the third strongest tidal force on Earth, after the Moon and the Sun, though
significantly less.[170]

Observability

Venus, pictured centre-right, is always brighter than all

other planets or stars at their maximal brightness, as seen from Earth. Jupiter is visible at the
top of the image.
To the naked eye, Venus appears as a white point of light brighter than any other planet or star
(apart from the Sun).[171] The planet's mean apparent magnitude is −4.14 with a standard
deviation of 0.31.[18] The brightest magnitude occurs during the crescent phase about one month
before or after an inferior conjunction. Venus fades to about magnitude −3 when it is backlit by
the Sun.[172] The planet is bright enough to be seen in broad daylight,[173] but is more easily visible
when the Sun is low on the horizon or setting. As an inferior planet, it always lies within about 47°
of the Sun.[174]
Venus "overtakes" Earth every 584 days as it orbits the Sun.[4] As it does so, it changes from the
"Evening Star", visible after sunset, to the "Morning Star", visible before sunrise. Although
Mercury, the other inferior planet, reaches a maximum elongation of only 28° and is often difficult
to discern in twilight, Venus is hard to miss when it is at its brightest. Its greater maximum
elongation means it is visible in dark skies long after sunset. As the brightest point-like object in
the sky, Venus is a commonly misreported "unidentified flying object".[175]
Phases
Main article: Phases of Venus
 The phases of Venus and evolution of its apparent diameter
As it orbits the Sun, Venus displays phases like those of the Moon in a telescopic view. The
planet appears as a small and "full" disc when it is on the opposite side of the Sun (at
superior conjunction). Venus shows a larger disc and "quarter phase" at its
maximum elongations from the Sun, and appears at its brightest in the night sky. The planet
presents a much larger thin "crescent" in telescopic views as it passes along the near side
between Earth and the Sun. Venus displays its largest size and "new phase" when it is between
Earth and the Sun (at inferior conjunction). Its atmosphere is visible through telescopes by the
halo of sunlight refracted around it.[174] The phases are clearly visible in a 4" telescope.[citation
needed]
Although naked eye visibility of Venus's phases is disputed, records exist of observations of
its crescent.[176]
Daylight apparitions

Venus is often visible to the naked eye in daytime, as seen

just prior to the lunar occultation of December 7th, 2015
When Venus is sufficiently bright with enough angular distance from the sun, it is easily observed
in a clear daytime sky with the naked eye, though most people do not know to look for it.
[177]
Astronomer Edmund Halley calculated its maximum naked eye brightness in 1716, when
many Londoners were alarmed by its appearance in the daytime. French emperor Napoleon
Bonaparte once witnessed a daytime apparition of the planet while at a reception in Luxembourg.
[178]
Another historical daytime observation of the planet took place during the inauguration of the
American president Abraham Lincoln in Washington, D.C., on 4 March 1865.[179]
Transits
Main article: Transit of Venus
 2012 transit of Venus, projected to a white card by
a telescope
A transit of Venus is the appearance of Venus in front of the Sun, during inferior conjunction.
Since the orbit of Venus is slightly inclined relative to Earth's orbit, most inferior conjunctions with
Earth, which occur every synodic period of 1.6 years, do not produce a transit of Venus above
Earth. Consequently, Venus transits above Earth only occur when an inferior conjunction takes
place during some days of June or December, the time where the orbits of Venus and Earth
cross a straight line with the Sun.[180] This results in Venus transiting above Earth in a sequence of
currently 8 years, 105.5 years, 8 years and 121.5 years, forming cycles of 243 years.
Historically, transits of Venus were important, because they allowed astronomers to determine
the size of the astronomical unit, and hence the size of the Solar System as shown by Jeremiah
Horrocks in 1639 with the first known observation of a Venus transit (after history's first observed
planetary transit in 1631, of Mercury).[181]
Only seven Venus transits have been observed so far, since their occurrences were calculated in
the 1621 by Johannes Kepler. Captain Cook sailed to Tahiti in 1768 to record the third observed
transit of Venus, which subsequently resulted in the exploration of the east coast of Australia. [182]
[183]

The latest pair was June 8, 2004 and June 5–6, 2012. The transit could be watched live from
many online outlets or observed locally with the right equipment and conditions. [184] The preceding
pair of transits occurred in December 1874 and December 1882.
The next transit will occur in December 2117 and December 2125.[185]
Ashen light
A long-standing mystery of Venus observations is the so-called ashen light—an apparent weak
illumination of its dark side, seen when the planet is in the crescent phase. The first claimed
observation of ashen light was made in 1643, but the existence of the illumination has never
been reliably confirmed. Observers have speculated it may result from electrical activity in the
Venusian atmosphere, but it could be illusory, resulting from the physiological effect of observing
a bright, crescent-shaped object.[186][77] The ashen light has often been sighted when Venus is in
the evening sky, when the evening terminator of the planet is towards Earth.

Observation and exploration history

Main article: Observations and explorations of Venus

Early observation
Venus is in Earth's sky bright enough to be visible without aid, making it one of the star-
like classical planets that human cultures have known and identified throughout history,
particularly for being the third brightest object in Earth's sky after the Sun and the Moon.
Because the movements of Venus appear to be discontinuous (it disappears due to its proximity
to the sun, for many days at a time, and then reappears on the other horizon), some cultures did
not recognise Venus as a single entity;[187] instead, they assumed it to be two separate stars on
each horizon: the morning and evening star.[187] Nonetheless, a cylinder seal from the Jemdet
Nasr period and the Venus tablet of Ammisaduqa from the First Babylonian dynasty indicate that
the ancient Sumerians already knew that the morning and evening stars were the same celestial
object.[188][187][189] In the Old Babylonian period, the planet Venus was known as Ninsi'anna, and later
as Dilbat.[190] The name "Ninsi'anna" translates to "divine lady, illumination of heaven", which
refers to Venus as the brightest visible "star". Earlier spellings of the name were written with
the cuneiform sign si4 (= SU, meaning "to be red"), and the original meaning may have been
"divine lady of the redness of heaven", in reference to the colour of the morning and evening sky.
[191]

The Chinese historically referred to the morning Venus as "the Great White" (Tàibái 太白) or "the
Opener (Starter) of Brightness" (Qǐmíng 啟明), and the evening Venus as "the Excellent West
One" (Chánggēng 長庚).[192]
The ancient Greeks initially believed Venus to be two separate stars: Phosphorus, the morning
star, and Hesperus, the evening star. Pliny the Elder credited the realization that they were a
single object to Pythagoras in the sixth century BC,[193] while Diogenes Laërtius argued
that Parmenides (early fifth century) was probably responsible for this discovery.[194] Though they
recognized Venus as a single object, the ancient Romans continued to designate the morning
aspect of Venus as Lucifer, literally "Light-Bringer", and the evening aspect as Vesper,[195] both of
which are literal translations of their traditional Greek names.
In the second century, in his astronomical treatise Almagest, Ptolemy theorized that both
Mercury and Venus were located between the Sun and the Earth. The 11th-century Persian
astronomer Avicenna claimed to have observed a transit of Venus (although there is some doubt
about it),[196] which later astronomers took as confirmation of Ptolemy's theory.[197] In the 12th
century, the Andalusian astronomer Ibn Bajjah observed "two planets as black spots on the face
of the Sun"; these were thought to be the transits of Venus and Mercury by 13th-
century Maragha astronomer Qotb al-Din Shirazi, though this cannot be true as there were no
Venus transits in Ibn Bajjah's lifetime.[198][note 4]
Venus and early modern astronomy
In 1610 Galileo Galilei observed with his telescope that Venus showed phases, despite remaining near the
Sun in Earth's sky (first image). This proved that it orbits the Sun and not Earth, as predicted
by Copernicus's heliocentric model and disproved Ptolemy's geocentric model (second image).

When the Italian physicist Galileo Galilei first observed the planet with a telescope in the early
17th century, he found it showed phases like the Moon, varying from crescent to gibbous to full
and vice versa. When Venus is furthest from the Sun in the sky, it shows a half-lit phase, and
when it is closest to the Sun in the sky, it shows as a crescent or full phase. This could be
possible only if Venus orbited the Sun, and this was among the first observations to clearly
contradict the Ptolemaic geocentric model that the Solar System was concentric and centred on
Earth.[201][202]
The 1639 transit of Venus was accurately predicted by Jeremiah Horrocks and observed by him
and his friend, William Crabtree, at each of their respective homes, on 4 December 1639 (24
November under the Julian calendar in use at that time).[203]

The "black drop effect" as recorded during the 1769 transit

The atmosphere of Venus was discovered in 1761 by Russian polymath Mikhail Lomonosov.[204]
[205]
Venus's atmosphere was observed in 1790 by German astronomer Johann Schröter. Schröter
found when the planet was a thin crescent, the cusps extended through more than 180°. He
correctly surmised this was due to scattering of sunlight in a dense atmosphere. Later, American
astronomer Chester Smith Lyman observed a complete ring around the dark side of the planet
when it was at inferior conjunction, providing further evidence for an atmosphere.[206] The
atmosphere complicated efforts to determine a rotation period for the planet, and observers such
as Italian-born astronomer Giovanni Cassini and Schröter incorrectly estimated periods of
about 24 h from the motions of markings on the planet's apparent surface.[207]
Early 20th century advances
Little more was discovered about Venus until the 20th century. Its almost featureless disc gave
no hint what its surface might be like, and it was only with the development
of spectroscopic and ultraviolet observations that more of its secrets were revealed.
Spectroscopic observations in the 1900s gave the first clues about the Venusian rotation. Vesto
Slipher tried to measure the Doppler shift of light from Venus, but found he could not detect any
rotation. He surmised the planet must have a much longer rotation period than had previously
been thought.[208]
The first ultraviolet observations were carried out in the 1920s, when Frank E. Ross found
that ultraviolet photographs revealed considerable detail that was absent in visible
and infrared radiation. He suggested this was due to a dense, yellow lower atmosphere with
high cirrus clouds above it.[209]
It had been noted that Venus had no discernible oblateness in its disk, suggesting a slow
rotation, and some astronomers concluded based on this that it was tidally locked like Mercury
was believed to be at the time; but other researchers had detected a significant quantity of heat
coming from the planet's nightside, suggesting a quick rotation (a high surface temperature was
not suspected at the time), confusing the issue.[210] Later work in the 1950s showed the rotation
was retrograde.
Space age
Further information: List of missions to Venus
Humanity's first interplanetary spaceflight was achieved in 1961 with the robotic space
probe Venera 1 of the Soviet Venera programme flying to Venus, though it lost contact en route.
[211]

Therefore, the first successful interplanetary mission was the Mariner 2 mission to Venus of the
United States' Mariner programme, passing on 14 December 1962 at 34,833 km (21,644 mi)
above the surface of Venus and gathering data on the planet's atmosphere. [212][213]
Additionally radar observations of Venus were first carried out in the 1960s, and provided the first
measurements of the rotation period, which were close to the actual value. [214]
Venera 3, launched in 1966, became humanity's first probe and lander to reach and impact
another celestial body other than the Moon, but could not return data as it crashed into the
surface of Venus. In 1967, Venera 4 was launched and successfully deployed science
experiments in the Venusian atmosphere before impacting. Venera 4 showed the surface
temperature was hotter than Mariner 2 had calculated, at almost 500 °C (932 °F), determined
that the atmosphere was 95% carbon dioxide (CO
2), and discovered that Venus's atmosphere was considerably denser than Venera 4's designers

had anticipated.[215]
In an early example of space cooperation the data of Venera 4 was joined with the 1967 Mariner
5 data, analysed by a combined Soviet–American science team in a series of colloquia over the
following year.[216]
On 15 December 1970, Venera 7 became the first spacecraft to soft land on another planet and
the first to transmit data from there back to Earth.[217]
In 1974, Mariner 10 swung by Venus to bend its path towards Mercury and took ultraviolet
photographs of the clouds, revealing the extraordinarily high wind speeds in the Venusian
atmosphere. This was the first interplanetary gravity assist ever used, a technique which would
be used by later probes.
Radar observations in the 1970s revealed details of the Venusian surface for the first time.
Pulses of radio waves were beamed at the planet using the 300 m (1,000 ft) radio telescope
at Arecibo Observatory, and the echoes revealed two highly reflective regions, designated
the Alpha and Beta regions. The observations revealed a bright region attributed to mountains,
which was called Maxwell Montes.[218] These three features are now the only ones on Venus that
do not have female names.[98]

First view and first clear

180-degree panorama of Venus's surface as well as any other planet than Earth (1975,
Soviet Venera 9 lander). Black-and-white image of barren, black, slate-like rocks against a
flat sky. The ground and the probe are the focus.
In 1975, the Soviet Venera 9 and 10 landers transmitted the first images from the surface of
Venus, which were in black and white. NASA obtained additional data with the Pioneer Venus
project that consisted of two separate missions:[219] the Pioneer Venus Multiprobe and Pioneer
Venus Orbiter, orbiting Venus between 1978 and 1992.[220] In 1982 the first colour images of the
surface were obtained with the Soviet Venera 13 and 14 landers. After Venera
15 and 16 operated between 1983 and 1984 in orbit, conducting detailed mapping of 25% of
Venus's terrain (from the north pole to 30°N latitude), the successful Soviet Venera programme
came to a close.[221]

Global topographic map of Venus, with

all probe landings marked
In 1985 the Vega programme with its Vega 1 and Vega 2 missions carried the last entry probes
and carried the first ever extraterrestrial aerobots for the first time achieving atmospheric flight
outside Earth by employing inflatable balloons.
Between 1990 and 1994, Magellan operated in orbit until deorbiting, mapping the surface of
Venus. Furthermore, probes like Galileo (1990),[222] Cassini–Huygens (1998/1999),
and MESSENGER (2006/2007) visited Venus with flybys flying to other destinations. In April
2006, Venus Express, the first dedicated Venus mission by the European Space Agency (ESA),
entered orbit around Venus. Venus Express provided unprecedented observation of Venus's
atmosphere. ESA concluded the Venus Express mission in December 2014 deorbiting it in
January 2015.[223]
In 2010, the first successful interplanetary solar sail spacecraft IKAROS travelled to Venus for a
flyby.
Active and future missions
Further information: List of missions to Venus § Future missions

WISPR visible light footage (2021) of the nightside,

showing the hot faintly glowing surface, and its Aphrodite Terra as large dark patch, through
the clouds, which prohibit such observations on the dayside when they are illuminated. [224][225]

As of 2023, the only active mission at Venus is Japan's Akatsuki, having achieved orbital
insertion on 7 December 2015. Additionally, several flybys by other probes have been performed
and studied Venus on their way, including NASA's Parker Solar Probe, and ESA's Solar
Orbiter and BepiColombo.
There are currently several probes under development as well as multiple proposed missions still
in their early conceptual stages.
Venus has been identified for future research as an important case for understanding:
  the origins of the solar system and Earth, and if systems and planets like ours are
common or rare in the universe.
 how planetary bodies evolve from their primordial states to today's diverse objects.
 the development of conditions leading to habitable environments and life. [226]

Search for life

Main article: Life on Venus
Speculation on the possibility of life on Venus's surface decreased significantly after the early
1960s when it became clear that conditions were extreme compared to those on Earth. Venus's
extreme temperatures and atmospheric pressure make water-based life, as currently known,
unlikely.
Some scientists have speculated that thermoacidophilic extremophile microorganisms might exist
in the cooler, acidic upper layers of the Venusian atmosphere.[227][228][229] Such speculations go back
to 1967, when Carl Sagan and Harold J. Morowitz suggested in a Nature article that tiny objects
detected in Venus's clouds might be organisms similar to Earth's bacteria (which are of
approximately the same size):
While the surface conditions of Venus make the hypothesis of life there implausible, the
clouds of Venus are a different story altogether. As was pointed out some years ago,
water, carbon dioxide and sunlight—the prerequisites for photosynthesis—are plentiful in
the vicinity of the clouds.[230]
In August 2019, astronomers led by Yeon Joo Lee reported that long-term pattern of
absorbance and albedo changes in the atmosphere of the planet Venus caused by
"unknown absorbers", which may be chemicals or even large colonies of microorganisms
high up in the atmosphere of the planet, affect the climate.[74] Their light absorbance is almost
identical to that of micro-organisms in Earth's clouds. Similar conclusions have been reached
by other studies.[231]
In September 2020, a team of astronomers led by Jane Greaves from Cardiff
University announced the likely detection of phosphine, a gas not known to be produced by
any known chemical processes on the Venusian surface or atmosphere, in the upper levels
of the planet's clouds.[232][56][55][233][234] One proposed source for this phosphine is living organisms.
[235]
The phosphine was detected at heights of at least 30 miles (48 km) above the surface,
and primarily at mid-latitudes with none detected at the poles. The discovery
prompted NASA administrator Jim Bridenstine to publicly call for a new focus on the study of
Venus, describing the phosphine find as "the most significant development yet in building the
case for life off Earth".[236][237]
Subsequent analysis of the data-processing used to identify phosphine in the atmosphere of
Venus has raised concerns that the detection-line may be an artefact. The use of a 12th-
order polynomial fit may have amplified noise and generated a false reading (see Runge's
phenomenon). Observations of the atmosphere of Venus at other parts of the
electromagnetic spectrum in which a phosphine absorption line would be expected did not
detect phosphine.[238] By late October 2020, re-analysis of data with a proper subtraction of
background did not show a statistically significant detection of phosphine.[239][240][241]
Members of the team around Greaves, are working as part of a project by the MIT to send
with the rocket company Rocket Lab the first private interplanetary space craft, to look for
organics by entering the atmosphere of Venus with a probe, set to launch in January 2025.[242]
Planetary protection
The Committee on Space Research is a scientific organisation established by
the International Council for Science. Among their responsibilities is the development of
recommendations for avoiding interplanetary contamination. For this purpose, space
missions are categorized into five groups. Due to the harsh surface environment of Venus,
Venus has been under the planetary protection category two.[243] This indicates that there is
only a remote chance that spacecraft-borne contamination could compromise investigations.
Human presence
Main article: List of missions to Venus
Venus is the place of the first interplanetary human presence, mediated through robotic
missions, with the first successful landings on another planet and extraterrestrial body other
than the Moon. Currently in orbit is Akatsuki, and other probes routinely use Venus
for gravity assist manoeuvres capturing some data about Venus on the way.[244]
The only nation that has sent lander probes to the surface of Venus has been the Soviet
Union,[note 5] which has been used by Russian officials to call Venus a "Russian planet". [245][246]
Crewed flight
Studies of routes for crewed missions to Mars have since the 1960s
proposed opposition missions instead of direct conjunction missions with Venus gravity
assist flybys, demonstrating that they should be quicker and safer missions to Mars, with
better return or abort flight windows, and less or the same amount of radiation exposure from
the flight as direct Mars flights.[247][248]
Early in the space age the Soviet Union and the United States proposed the TMK-MAVR
and Manned Venus flyby crewed flyby missions to Venus, though they were never realized.
Habitation
See also: Colonization of Venus and Floating cities and islands in fiction § Venus

Artist's rendering of a NASA High Altitude Venus

Operational Concept (HAVOC) crewed floating outpost on Venus
While the surface conditions of Venus are inhospitable, the atmospheric pressure,
temperature, and solar and cosmic radiation 50 km above the surface are similar to those at
Earth's surface.[131][130] With this in mind, Soviet engineer Sergey Zhitomirskiy (Сергей
Житомирский, 1929–2004) in 1971[249][250] and NASA aerospace engineer Geoffrey A.
Landis in 2003[251] suggested the use of aerostats for crewed exploration and possibly for
permanent "floating cities" in the Venusian atmosphere, an alternative to the popular idea of
living on planetary surfaces such as Mars.[252][253] Among the many engineering challenges for
any human presence in the atmosphere of Venus are the corrosive amounts of sulfuric
acid in the atmosphere.[251]
NASA's High Altitude Venus Operational Concept is a mission concept that proposed a
crewed aerostat design.

In culture
Main article: Venus in culture
 Venus is portrayed just to the right of the large cypress
tree in Vincent van Gogh's 1889 painting The Starry Night. [254][255]

Venus is a primary feature of the night sky, and so has been of remarkable importance
in mythology, astrology and fiction throughout history and in different cultures.
The English name of Venus was originally the ancient Roman name for it. Romans named
Venus after their goddess of love, who in turn was based on the ancient Greek goddess of
love Aphrodite,[256] who was herself based on the similar Sumerian
religion goddess Inanna (which is Ishtar in Akkadian religion), all of whom were associated
with the planet.[257][258] The weekday of the planet and these goddesses is Friday, named after
the Germanic goddess Frigg, who has been associated with the Roman goddess Venus.

The eight-pointed star a symbol used in some cultures

for Venus, and sometimes combined into a star and crescent arrangement. Here the eight
pointed star is the Star of Ishtar, the Babylonian Venus goddess, alongside the solar
disk of her brother Shamash and the crescent moon of their father Sin on a boundary
stone of Meli-Shipak II, dating to the twelfth century BC.
Several hymns praise Inanna in her role as the goddess of the planet Venus. [187][258]
[257]
Theology professor Jeffrey Cooley has argued that, in many myths, Inanna's movements
may correspond with the movements of the planet Venus in the sky.[187] The discontinuous
movements of Venus relate to both mythology as well as Inanna's dual nature. [187] In Inanna's
Descent to the Underworld, unlike any other deity, Inanna is able to descend into the
netherworld and return to the heavens. The planet Venus appears to make a similar descent,
setting in the West and then rising again in the East.[187] An introductory hymn describes
Inanna leaving the heavens and heading for Kur, what could be presumed to be, the
mountains, replicating the rising and setting of Inanna to the West.[187] In Inanna and
Shukaletuda and Inanna's Descent into the Underworld appear to parallel the motion of the
planet Venus.[187] In Inanna and Shukaletuda, Shukaletuda is described as scanning the
heavens in search of Inanna, possibly searching the eastern and western horizons. [259] In the
same myth, while searching for her attacker, Inanna herself makes several movements that
correspond with the movements of Venus in the sky.[187]
The Ancient Egyptians and ancient Greeks possibly knew by the second millennium BC or at
the latest by the Late Period, under mesopotamian influence that the morning star and an
evening star were one and the same.[260][261] The Egyptians knew the morning star
as Tioumoutiri and the evening star as Ouaiti.[262] They depicted Venus at first as
a phoenix or heron (see Bennu),[260] calling it "the crosser" or "star with crosses",
[260]
associating it with Osiris, and later depicting it two-headed with human or falco heads,
and associated it with Horus,[261] son of Isis (which during the even later Hellenistic period was
together with Hathor identified with Aphrodite). The Greeks used the
names Phōsphoros (Φωσϕόρος), meaning "light-bringer" (whence the element phosphorus;
alternately Ēōsphoros (Ἠωσϕόρος), meaning "dawn-bringer"), for the morning star,
and Hesperos (Ἕσπερος), meaning "Western one", for the evening star,[263] both children of
dawn Eos and therefore grandchildren of Aphrodite. Though by the Roman era they were
recognized as one celestial object, known as "the star of Venus", the traditional two Greek
names continued to be used, though usually translated to Latin as Lūcifer and Vesper.[263][264]
Classical poets such as Homer, Sappho, Ovid and Virgil spoke of the star and its light.
[265]
Poets such as William Blake, Robert Frost, Letitia Elizabeth Landon, Alfred Lord
Tennyson and William Wordsworth wrote odes to it.[266]
In India, Shukra Graha ("the planet Shukra") is named after the powerful saint
Shukra. Shukra which is used in Indian Vedic astrology[267] means "clear, pure" or "brightness,
clearness" in Sanskrit. One of the nine Navagraha, it is held to affect wealth, pleasure and
reproduction; it was the son of Bhrgu, preceptor of the Daityas, and guru of the Asuras.
[268]
The word Shukra is also associated with semen, or generation.
Venus is known as Kejora in Indonesian and Malaysian Malay.
In Chinese the planet is called Jīn-xīng (金星), the golden planet of the metal element.
Modern Chinese, Japanese, Korean and Vietnamese cultures refer to the planet literally as
the "metal star" (金星), based on the Five elements.[269][270][271][272]
The Maya considered Venus to be the most important celestial body after the Sun and Moon.
They called it Chac ek,[273] or Noh Ek', "the Great Star".[274] The cycles of Venus were important
to their calendar and were described in some of their books such as Maya Codex of
Mexico and Dresden Codex.
Modern culture
See also: Venus in fiction
With the invention of the telescope, the idea that Venus was a physical world and a possible
destination began to take form.
The impenetrable Venusian cloud cover gave science fiction writers free rein to speculate on
conditions at its surface; all the more so when early observations showed that not only was it
similar in size to Earth, it possessed a substantial atmosphere. Closer to the Sun than Earth,
the planet was often depicted as warmer, but still habitable by humans.[275] The genre
reached its peak between the 1930s and 1950s, at a time when science had revealed some
aspects of Venus, but not yet the harsh reality of its surface conditions. Findings from the
first missions to Venus showed reality to be quite different and brought this particular genre
to an end.[276] As scientific knowledge of Venus advanced, science fiction authors tried to
keep pace, particularly by conjecturing human attempts to terraform Venus.[277]
Symbols
Main article: Venus symbol

The symbol of a circle with a small cross beneath is the so-called Venus symbol, gaining its
name for being used as the astronomical symbol for Venus. The symbol is of ancient
Greek origin, and represents more generally femininity, adopted by biology as gender
symbol for female,[278][279][280] like the Mars symbol for male and sometimes the Mercury
symbol for hermaphrodite. This gendered association of Venus and Mars has been used to
pair them heteronormatively, describing women and men stereotypically as being so different
that they can be understood as coming from different planets, an understanding popularized
in 1992 by the book titled Men Are from Mars, Women Are from Venus.[281][282]
The Venus symbol was also used in Western alchemy representing the element copper (like
the symbol of Mercury is also the symbol of the element mercury),[279][280] and since polished
copper has been used for mirrors from antiquity the symbol for Venus has sometimes been
called Venus mirror, representing the mirror of the goddess, although this origin has been
discredited as an unlikely origin.[279][280]
Besides the Venus symbol, many other symbols have been associated with Venus, other
common ones are the crescent or particularly the star, as with the Star of Ishtar.

See also

 Solar System portal

 Outer space portal

 Astronomy portal

 Outline of Venus
 Physical properties of planets in the Solar System
 Venus zone

Notes
1. ^ Misstated as "Ganiki Chasma" in the press release and scientific publication.[115]
2. ^ The equatorial speed of Earth is given as both about 1674.4 km/h and 1669.8 km/h
by reliable sources. The simplest way to determine the correct figure is to multiply
Earth's radius of 6378137 m (WGS84) and Earth's angular
speed, 7.2921150×10−5 rad/s,[142] yielding 465.1011 m/s = 1674.364 km/h. The
incorrect figure of 1669.8 km/h is obtained by dividing Earth's equatorial
circumference by 24 h. But the correct speed must be relative to inertial space, so
the stellar day of 86164.098903691 s/3600 = 23.934472 h (23 h 56 m 4.0989 s) must
be used.[143] Thus 2π(6378.137 km)/23.934472 h = 1674.364 km/h.[144]
3. ^ It is important to be clear about the meaning of "closeness". In the astronomical
literature, the term "closest planets" often refers to the two planets that approach
each other the most closely. In other words, the orbits of the two planets approach
each other most closely. However, this does not mean that the two planets are
closest over time. Essentially because Mercury is closer to the Sun than Venus,
Mercury spends more time in proximity to Earth; it could, therefore, be said that
Mercury is the planet that is "closest to Earth when averaged over time". However,
using this time-average definition of "closeness", it turns out that Mercury is the
closest planet to all other planets in the solar system. For that reason, arguably, the
proximity-definition is not particularly helpful. An episode of the BBC Radio 4
programme "More or Less" explains the different notions of proximity well. [164]
4. ^ Several claims of transit observations made by mediaeval Islamic astronomers
have been shown to be sunspots.[199] Avicenna did not record the date of his
observation. There was a transit of Venus within his lifetime, on 24 May 1032,
although it is questionable whether it would have been visible from his location.[200]
5. ^ The American Pioneer Venus Multiprobe has brought the only non-Soviet probes
to enter the atmosphere, as atmospheric entry probes only briefly signals were
received from the surface.

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