View source for Venus

{{Short description|Second planet from the Sun}}
{{About|the planet|the deity|Venus (mythology)|other uses}}
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{{Use Oxford spelling|date=August 2024}}
{{Use dmy dates|date=August 2024}}
{{Infobox planet
| name = Venus
| image = <!-- Do not change this image without discussion in the Talk page. By consensus only normal-light images should be used in the infobox image of the planets --> Venus-real_color.jpg
| symbol = [[File:Venus symbol (bold).svg|24px|♀|class=skin-invert]]
| caption = Image of Venus, combining two images from ''[[Mariner 10]]'', one with a clear filter and one with a blue filter, balanced to approximate realistic colors assuming a yellowish overall hue.<ref>{{Cite web |last=Ricardo |first=Nunes |title=Ricardo Nunes Astronomy Page |url=http://www.astrosurf.com/nunes/explor_m10.html |access-date=2025-11-19 |website=www.astrosurf.com}}</ref> A cloud layer permanently obscures the surface. 

| background = LightSalmon
| orbit_ref = <ref name="fact" /><ref name="horizons" />
| epoch = [[J2000]]
| aphelion = {{convert|0.728213|AU|e6km|2|abbr=unit|lk=in}}
| perihelion = {{convert|0.718440|AU|e6km|2|abbr=unit}}
| semimajor = {{convert|0.723332|AU|e6km|2|abbr=unit}}
| eccentricity = 0.006772<ref name="VSOP87" />
| period = {{plainlist |
* {{val|224.701|u=day}}<ref name="fact" />
* {{val|0.615198|u=[[Julian year (astronomy)|Julian year]]}}
* {{val|0.615187|u=[[sidereal year]]}}
* 1.92 Venus [[solar day]]
  }}
| synodic_period = 583.92 days<ref name="fact" />
| avg_speed = 35.02{{spaces}}km/s
| inclination = {{plainlist |
* {{val|3.39458|u=°}} to [[ecliptic]]
* 3.86° to [[Sun]]'s [[equator]]
* 2.15° to [[invariable plane]]<ref name=Souami_Souchay_2012 />
  }}
| asc_node = 76.680°<ref name="VSOP87" />
| arg_peri = 54.884°
| mean_anomaly = 50.115°
| satellites = None
| allsatellites = yes
| mean_radius = {{plainlist |
* {{nowrap|{{val|fmt=commas|6051.8|1.0|u=km}}}}<ref name="Seidelmann2007" />
* {{val|0.9499|u=Earths}}
  }}
| flattening = 0<ref name="Seidelmann2007" />
| surface_area = {{plainlist |
* {{val|4.6023|e=8|u=km2}}
* 0.902 Earths
  }}
| volume = {{plainlist |
* {{val|9.2843|e=11|u=km3}}
* 0.857 Earths
  }}
| mass = {{plainlist |
* {{val|4.8675|e=24|u=kg}}<ref name="Konopliv1999" />
* 0.815 Earths
  }}
| density = {{val|5.243|u=g/cm3}}
| surface_grav = {{cvt|8.87|m/s2|g0|lk=out}}
| escape_velocity = {{convert|10.36|km/s|abbr=on}}<ref name=NASA_2015/>
| rotation = {{val|-116.75|u=day}} ([[Retrograde motion|retrograde]])<ref name="planetary-facts"/>
<br />1 Venus solar day
| sidereal_day = {{val|-243.0226|u=day}} (retrograde)<ref name=Margot_et_al_2021/>
| rot_velocity = {{cvt|6.52|km/h|m/s|disp=out}}<!--Since rot. vel. = circumference/sidereal day, and circumference is 2πr, rot. vel. = 2π6051km/243.025*24h = 6.52 km/h-->
| axial_tilt = 2.64° (for [[Retrograde motion|retrograde]] rotation){{break}}177.36° (to orbit)<ref name=fact/>{{refn|group=note|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°.}}
| right_asc_north_pole = {{plainlist |
* {{RA|18|11|2}}
* 272.76°<ref name="iauwg_ccrsps2000" /><ref name="iau2015">{{Cite journal |last1=Archinal |first1=B. A. |last2=Acton |first2=C. H. |last3=A'Hearn |first3=M. F. |last4=Conrad |first4=A. |last5=Consolmagno |first5=G. J. |last6=Duxbury |first6=T. |last7=Hestroffer |first7=D. |last8=Hilton |first8=J. L. |last9=Kirk |first9=R. L. |last10=Klioner |first10=S. A. |last11=McCarthy |first11=D. |last12=Meech |first12=K. |last13=Oberst |first13=J. |last14=Ping |first14=J. |last15=Seidelmann |first15=P. K. |date=2018 |title=Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015 |url=http://link.springer.com/10.1007/s10569-017-9805-5 |journal=Celestial Mechanics and Dynamical Astronomy |language=en |volume=130 |issue=3 |page=22 |doi=10.1007/s10569-017-9805-5 |bibcode=2018CeMDA.130...22A |issn=0923-2958|url-access=subscription }}</ref>
  }}
| declination = 67.16°<ref name="iau2015" />
| albedo = {{plainlist |
* 0.689 ([[Geometric albedo|geometric]])<ref name="Mallama_et_al"/>
* 0.76 ([[Bond albedo|Bond]])<ref name="Haus_et_al"/>
  }}
| magnitude = −4.92 to −2.98<ref name="Mallama_and_Hilton"/>
| abs_magnitude = −4.4<ref name="IMCCE">{{cite web | title=Encyclopedia – the brightest bodies | website=IMCCE | url=https://promenade.imcce.fr/en/pages5/572.html | access-date=29 May 2023 | archive-date=24 July 2023 | archive-url=https://web.archive.org/web/20230724225002/https://promenade.imcce.fr/en/pages5/572.html | url-status=live }}</ref>
| angular_size = {{nowrap|9.7{{pprime}}–66.0{{pprime}}}}<ref name="fact" />
| single_temperature = {{cvt|232|K|°C|0}} ([[Effective temperature|blackbody temperature]])<ref name="American Chemical Society 2013"/>
| temp_name1 = [[Kelvin]]
| mean_temp_1 = 737 K<ref name="fact" />
| temp_name2 = [[Celsius]]
| mean_temp_2 = 464 °C
| temp_name3 = [[Fahrenheit]]
| mean_temp_3 = 867 °F
| surface_equivalent_dose_rate = {{convert |{{#expr:10^(19/54)}}e-9 |mSv/h |μSv/h |sigfig=2 |disp=out}}<br/>{{convert |{{#expr:10^(52/54)}}e-5 |- |{{#expr:10^(19/54)}}e-2 |mSv/h |μSv/h |sigfig=2 |disp=out}} at cloud level<ref name="radiation-levels"/><!-- pixel values measured from the referenced figure -->
| surface_absorbed_dose_rate = {{convert |{{#expr:10^(17/54)}}e-9 |mGy/h |μGy/h |sigfig=2 |disp=out}}<ref name="radiation-levels"/>
| pronounced = {{IPAc-en|audio=en-us-Venus.ogg|ˈ|v|iː|n|ə|s}}
| named_after = [[Roman religion|Roman]] [[List of love and lust deities|goddess of love]] (see [[goddess Venus]])
| adjectives = {{nowrap|[[Venusian (disambiguation)|Venusian]] {{IPAc-en|v|ᵻ|ˈ|nj|uː|z|i|ə|n|,_|-|ʒ|ə|n}},<ref name=Lexico_Venusian/>}} rarely [[Cytherean]] {{IPAc-en|s|ɪ|θ|ə|'|r|iː|ə|n}}<ref>{{OED|Cytherean}}</ref> or Venerean / Venerian {{IPAc-en|v|ᵻ|ˈ|n|ɪər|i|ə|n}}<ref>{{OED|Venerean, Venerian}}</ref>
| atmosphere = yes
| atmosphere_ref = <ref name="fact" />
| surface_pressure = 93&nbsp;[[bar (unit)|bar]] (9.3&nbsp;[[Pascal (unit)|MPa]]){{break}}92 [[atmosphere (unit)|atm]]
| atmosphere_composition = {{plainlist | 
* 96.5% [[carbon dioxide]]
* 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]]
  }}
}}

'''Venus''' is the second [[planet]] from the [[Sun]]. It is often called [[Earth]]'s "twin" or "sister" among the planets of the [[Solar System]] for its orbit being the closest to Earth's, both being [[rocky planet]]s, and having the most similar and nearly equal size, mass, and [[surface gravity]]. Venus, though, is significantly different, especially as it has no [[liquid water]], and [[Atmosphere of Venus|its atmosphere]] is far thicker and denser than that of any other rocky body in the Solar System. The atmosphere is composed mostly of [[carbon dioxide]] and has a thick cloud layer of [[sulfuric acid]] that spans the whole planet. At the mean surface level, the atmosphere reaches a temperature of {{convert|737|K|C F|abbr=on}} and a [[atmospheric pressure|pressure]] 92 times greater than Earth's at sea level, turning the lowest layer of the atmosphere into a [[supercritical fluid]]. From Earth, Venus is visible as a star-like point of light, [[apparent brightness|appearing brighter]] than any other natural point of light in the sky,<ref name="Lawrence_2005" /><ref name="Walker_2017" /> and as an [[inferior planet]] always relatively close to the Sun, either as the brightest "morning star" or "evening star".

The orbits of Venus and Earth make the two planets approach each other in [[synodic period]]s of 1.6 years. In the course of this, Venus comes closer to Earth than any other planet, in contrast to [[Mercury (planet)|Mercury]] which stays closer over the course of an orbit to Earth than any other planet, due to its orbit being closer to the Sun. In [[interplanetary spaceflight]] from Earth, Venus is frequently used as a waypoint for [[gravity assist]]s, offering a faster and more economical route. Venus has no [[moons]] and a very slow [[Retrograde and prograde motion|retrograde]] rotation about its axis, a result of competing forces of solar tidal locking and differential heating of Venus's massive atmosphere. As a result, a Venusian day is 116.75 Earth days long, about half a Venusian [[solar year]], which is 224.7 Earth days long.

Venus has a weak [[magnetosphere]]; lacking an [[Dynamo theory|internal dynamo]], it is induced by the [[solar wind]] interacting with the atmosphere. Internally, Venus has a [[Planetary core|core]], a [[Mantle (geology)|mantle]], and a [[Crust (geology)|crust]]. [[Internal heat]] escapes through active [[volcanism]],<ref name="NYT-20240527">{{cite news |last=Andrews |first=Roy George |title=Rivers of Lava on Venus Reveal a More Volcanically Active Planet - New software let scientists re-examine old radar images, providing some of the strongest evidence yet that volcanoes continue to reshape the hellish planet. |url=https://www.nytimes.com/2024/05/27/science/venus-volcanoes-lava.html |date=27 May 2024 |work=[[The New York Times]] |url-status=live |archive-url=https://archive.today/20240528023048/https://www.nytimes.com/2024/05/27/science/venus-volcanoes-lava.html |archive-date=28 May 2024 |access-date=28 May 2024}}</ref><ref name="NA-20240527">{{cite journal |last1=Sulcanese |first1=Davide |last2=Mitri |first2=Giuseppe |last3=Mastrogiuseppe |first3=Marco |title=Evidence of ongoing volcanic activity on Venus revealed by Magellan radar |url=https://www.nature.com/articles/s41550-024-02272-1 |date=27 May 2024 |journal=[[Nature Astronomy]] |volume=8 |issue=8 |pages=973–982 |doi=10.1038/s41550-024-02272-1 |bibcode= 2024NatAs...8..973S|url-status=live |archive-url=https://archive.today/20240528101249/https://www.nature.com/articles/s41550-024-02272-1 |archive-date=28 May 2024 |access-date=28 May 2024 | issn = 2397-3366 |url-access=subscription }}</ref> resulting in [[Geology of Venus#Global resurfacing event|resurfacing]], instead of [[plate tectonics]]. Venus may have had liquid surface water early in its history with a [[Planetary habitability|habitable environment]],<ref name="NYT-20231026" /><ref name="NA-20231026" /> before a [[runaway greenhouse effect]] evaporated any water and turned Venus into its present state.<ref name="Jakosky" /><ref name="Hashimoto_et_al_2008" /><ref name="Shiga_2007" /> There are atmospheric conditions at cloud layer altitudes that are the most similar ones to Earth in the Solar System and have been identified as possibly favourable for [[life on Venus]], with potential biomarkers found in 2020, spurring new research and [[missions to Venus]].

Throughout history humans  across the globe have observed Venus and it has acquired particular importance in many cultures. With telescopes, the [[phases of Venus]] became discernible and, by 1613, were presented as decisive evidence disproving the then-dominant [[geocentric model]] and supporting the [[heliocentric model]]. Venus was visited for the first time in 1961 by [[Venera 1]], which flew past the planet, achieving the first interplanetary spaceflight. The first data from Venus were returned during the second interplanetary mission, [[Mariner 2]], in 1962. In 1967, the first interplanetary impactor, [[Venera 4]], reached Venus, followed by the lander [[Venera 7]] in 1970. {{As of|2025}}, [[Solar Orbiter]] is on its way to fly-by Venus in 2026, and the next mission planned to launch to Venus is the [[Venus Life Finder]], scheduled for 2026 as well.

== Physical characteristics ==
[[File:Terrestrial planet size comp 2024.png|thumb|upright=1.3|Venus (second from the left, in false-colour) to scale among the [[Inner Solar System]] [[planetary-mass object]]s, arranged by the order of their orbits outward from the Sun (from left: [[Mercury (planet)|Mercury]], Venus,
[[Earth]], the [[Moon]], [[Mars]] and [[Ceres (dwarf planet)|Ceres]])]]
[[File:11214 2023 956 Fig3 HTML.webp|thumb|upright=1.3|Venus imaged in different wavelengths]]

Venus is one of the four [[terrestrial planet]]s 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".<ref name= "Lopes_Gregg_2004"/> Venus is very close to spherical due to its slow rotation.<ref name="Venus"/> It has a diameter of {{convert|12103.6|km|mi|abbr=on}}—only {{convert|638.4|km|mi|abbr=on}} less than Earth's—and its mass is 81.5% of Earth's, making it the third-smallest planet in the [[Solar System]]. Conditions on the surface of Venus differ radically from those on Earth because its dense [[atmosphere]] is 96.5% carbon dioxide, causing an intense [[greenhouse effect]], with most of the remaining 3.5% being [[nitrogen]].<ref name=Darling_Venus/> The surface pressure is {{convert|9.3|MPa|bar|lk=on|abbr=off}}, and the average surface temperature is {{convert|737|K|C F|abbr=on}}, above the [[Critical point (thermodynamics)|critical points]] of both major constituents and making the surface atmosphere a [[supercritical fluid]] of mainly [[supercritical carbon dioxide]] and some supercritical nitrogen.

=== Natural history ===
==== Formation ====
{{More|Nebular hypothesis}}
The rocky terrestrial planets including Venus are thought to have formed in 5 stages: dust settling, [[planetesimal]] formation, planetary embryos, giant impacts, and finally formation of atmospheres. Limited measurements from Venus have prevented a more detailed analysis of the formation timeline.<ref>{{Cite journal |last1=Lammer |first1=Helmut |last2=Brasser |first2=Ramon |last3=Johansen |first3=Anders |last4=Scherf |first4=Manuel |last5=Leitzinger |first5=Martin |date=February 2021 |title=Formation of Venus, Earth and Mars: Constrained by Isotopes |url=http://link.springer.com/10.1007/s11214-020-00778-4 |journal=Space Science Reviews |language=en |volume=217 |issue=1 |article-number=7 |doi=10.1007/s11214-020-00778-4 |issn=0038-6308|arxiv=2102.06173 }}</ref>

==== Future ====
Venus is expected to be destroyed, along with Mercury, and possibly the Earth and the Moon, when the Sun becomes a [[red giant]] in approximately seven or eight billion years.<ref>{{Cite web |date=December 11, 2018 |title=Chapter 6: Aging Into Gianthood - NASA Science |url=https://science.nasa.gov/exoplanets/resources/life-and-death/chapter-6/ |access-date=2025-09-07 |language=en-US}}</ref>

=== Geography ===
{{Main|Geology of Venus|Geodynamics of Venus|Mapping of Venus|Surface features of Venus}}

[[File:2438_pioneer_venus_map_of_venus.jpg|thumb|upright=1.5|Colour-coded elevation map, showing the elevated [[Planetary nomenclature#Terra|terrae]] "continents" in yellow and minor [[Surface features of Venus|features of Venus]]]]
[[File:Venus globe.jpg|thumb|[[Sphere|Spherical]] view of radar data of the [[Mapping of Venus|surface of Venus]], highlighting [[List of geological features on Venus|surface features]] (1989, [[Magellan (spacecraft)|Magellan]]). The colours do not represent the appearance of the surface.<ref name="k285">{{cite web | last=Koren | first=Marina | title=Our Solar System in True Color Is Really Something Else | website=The Atlantic | date=February 3, 2022 | url=https://www.theatlantic.com/science/archive/2022/02/venus-true-color-solar-system/621460/ | access-date=June 24, 2025}}</ref>]]

The Venusian surface was a subject of speculation until some of its secrets were revealed by probes in the 20th century. ''[[Venera]]'' landers in 1975 and 1982 returned images of a surface covered in sediment and relatively angular rocks.<ref name=Mueller_2014/> The surface was mapped in detail by [[Magellan (spacecraft)|''Magellan'']] in 1990–91. There is evidence of extensive volcanism, and variations in the atmospheric [[sulphur dioxide]] may indicate that there are active volcanoes.<ref name=Esposito_1984/><ref name=Bullock_Grinspoon_2001/>

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.<ref name=Basilevsky_Head_1995/> Two [[highland continent|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 [[Babylon]]ian goddess of love, and is about the size of Australia. The [[Maxwell Montes]] mountain range lies on Ishtar Terra. Its peak [[Skadi Mons]] is the highest point on Venus, {{convert|7|mi|km|order=flip|abbr=on}} above the Venusian average surface elevation.<ref name="planetology"/> 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.<ref name="Kaufmann"/>

There is recent evidence of [[lava]] flow on Venus (2024),<ref>National Geographic [https://www.nationalgeographic.com/science/article/venus-is-volcanically-alive (2024) Venus is volcanically alive]</ref> such as flows on [[Sif Mons]], a shield volcano, and on [[Niobe Planitia]], a flat plain.<ref name="NYT-20240527" /> There are visible [[caldera]]s. The planet has few [[impact crater]]s, demonstrating that the surface is relatively young, at 300–600{{spaces}}million years old.<ref name="Nimmo98" /><ref name="Strom1994" /> 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 (Venus)|farra]]", which look somewhat like pancakes and range in size from {{convert|20|to|50|km|mi|abbr=on}} across, and from {{convert|100|to|1000|m|ft|abbr=on}} high; radial, star-like fracture systems called "novae"; features with both radial and concentric fractures resembling spider webs, known as "[[arachnoid (astrogeology)|arachnoids]]"; and "coronae", circular rings of fractures sometimes surrounded by a depression. These features are volcanic in origin.<ref name="Frankel"/>

[[File:USSR Venera 9 1975 Venus ground colorized by Don P. Mitchell.png|thumb|Colourized image ([[Venera 9]], 1975), the colour of the Venusian sky is at the surface orange-yellow due to [[rayleigh scattering]] or a blue absorber in the lower atmosphere, being white at higher altitudes,<ref>{{cite web | last=Mitchell | first=Don P. | title=Soviet Venus Images | website=Don P. Mitchell | date=October 20, 1975 | url=http://mentallandscape.com/C_CatalogVenus.htm | access-date=June 2, 2025}}</ref><ref name="t069"/> while the surface is a [[basalt]]-like dark gray, which is possibly oxidized red.<ref name="k285"/>]]

Most [[List of geological features on Venus|Venusian surface features]] are named after historical and mythological women.<ref name="Batson_Russell_1991"/> 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]].<ref name="jpl-magellan"/>

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.<ref name="Davies_1994"/> After the Venera missions were completed, the prime meridian was redefined to pass through the central peak in the crater [[Ariadne (crater)|Ariadne]] on [[Sedna Planitia]].<ref name="Seidelmann2007" /><ref name="jpl-magellan2"/>

The stratigraphically oldest [[Tessera (Venus)|tessera terrains]] have consistently lower thermal emissivity than the surrounding basaltic plains measured by ''[[Venus Express]]'' and [[Magellan (spacecraft)|''Magellan'']], indicating a different, possibly a more [[felsic]], mineral assemblage.<ref name="Hashimoto_et_al_2008"/><ref name=Helbert_et_al_2008/> The mechanism to generate a large amount of felsic crust usually requires the presence of a water ocean and [[plate tectonics]], implying that habitable condition existed on early Venus, with large bodies of water at some point.<ref name="Petkowski Seager 2021">{{cite web | last1=Petkowski | first1=Janusz | last2=Seager | first2=Sara | title=Did Venus ever have oceans? | website=Venus Cloud Life – MIT | date=18 November 2021 | url=https://venuscloudlife.com/are-venus-cloud-layers-too-dry-for-life/ | access-date=13 April 2023 | archive-date=13 April 2023 | archive-url=https://web.archive.org/web/20230413112527/https://venuscloudlife.com/are-venus-cloud-layers-too-dry-for-life/ | url-status=live }}</ref> However, the nature of tessera terrains is far from certain.<ref name=Gilmore_et_al_2017/>

Studies reported in 2023 suggested for the first time that Venus may have had [[plate tectonics]] during ancient times and, as a result, may have had a more [[Planetary habitability|habitable environment]], possibly one capable of sustaining [[life forms|life]].<ref name="NYT-20231026">{{cite news |last=Chang |first=Kenneth |title=Billions of Years Ago, Venus May Have Had a Key Earthlike Feature – A new study makes the case that the solar system's hellish second planet once may have had plate tectonics that could have made it more hospitable to life. |url=https://www.nytimes.com/2023/10/26/science/venus-plate-tectonics-life.html |date=26 October 2023 |work=[[The New York Times]] |url-status=live |archive-url=https://archive.today/20231026181052/https://www.nytimes.com/2023/10/26/science/venus-plate-tectonics-life.html |archive-date=26 October 2023 |access-date=27 October 2023 }}</ref><ref name="NA-20231026">{{cite journal |author=Weller, Matthew B. |display-authors=et al. |title=Venus's atmospheric nitrogen explained by ancient plate tectonics |url=https://www.nature.com/articles/s41550-023-02102-w |date=26 October 2023 |journal=[[Nature Astronomy]] |volume=7 |issue=12 |pages=1436–1444 |doi=10.1038/s41550-023-02102-w |bibcode=2023NatAs...7.1436W |s2cid=264530764 |url-status=live |archive-url=https://archive.today/20231027132655/https://www.nature.com/articles/s41550-023-02102-w |archive-date=27 October 2023 |access-date=27 October 2023 |url-access=subscription }}</ref> Venus has gained interest as a case for research into the development of [[Earth analogue|Earth-like planets]] and [[planetary habitability|their habitability]].

==== Volcanism ====
{{Main|Volcanism on Venus}}
[[Image:PIA00084 Eistla region pancake volcanoes.jpg|thumb|left|upright=1.1|Radar mosaic of two [[pancake dome]]s in Venus's Eistla region—both {{Convert|65|km|mi|abbr=on}} wide and less than {{Convert|1|km|mi|abbr=on}} high]]

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 {{convert|100|km|mi|sigfig=1|abbr=on}} across. The only volcanic complex of this size on Earth is the [[Hawaii (island)|Big Island]] of Hawaii.<ref name="Frankel" />{{rp|154}} More than 85,000 volcanoes on Venus have been identified and mapped.<ref>{{cite web |title=A new catalog pinpoints volcanic cones in the best available surface images of Venus – those gathered 30 years ago by NASA's Magellan spacecraft. |url=https://skyandtelescope.org/astronomy-news/85000-volcanoes-mapped-on-venus |website=skyandtelescope.org |date=14 April 2023 |access-date=16 April 2023 |archive-date=16 April 2023 |archive-url=https://web.archive.org/web/20230416223821/https://skyandtelescope.org/astronomy-news/85000-volcanoes-mapped-on-venus/ |url-status=live }}</ref><ref>{{cite journal |last1=Hahn |first1=Rebecca M. |last2=Byrne |first2=Paul K. |title=A Morphological and Spatial Analysis of Volcanoes on Venus |journal=Journal of Geophysical Research: Planets |date=April 2023 |volume=128 |issue=4 |article-number=e2023JE007753 |doi=10.1029/2023JE007753 |bibcode=2023JGRE..12807753H |s2cid=257745255 |quote=With the Magellan synthetic-aperture radar full-resolution radar map left- and right-look global mosaics at 75 m-per-pixel resolution, we developed a global catalogue of volcanoes on Venus that contains ~85,000 edifices, ~99% of which are <5 km in diameter. We find that Venus hosts far more volcanoes than previously mapped, and that although they are distributed across virtually the entire planet, size–frequency distribution analysis reveals a relative lack of edifices in the 20–100 km diameter range, which could be related to magma availability and eruption rate.}}</ref> This is not because Venus is more volcanically active than Earth, but because its crust is older and is not subject to the [[erosion]] processes active on Earth. 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,<ref name=Karttunen_et_al_2007/> whereas the Venusian surface is estimated to be 300–600{{spaces}}million years old.<ref name="Nimmo98" /><ref name="Frankel" />

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.<ref name="ESA_2012-12-03"/> This may mean that levels were boosted several times by large volcanic eruptions.<ref name=Glaze_1999/><ref name="Marcq2012"/> It has been suggested that Venusian lightning (discussed below) could originate from volcanic activity (i.e. [[volcanic lightning]]). In January 2020, astronomers reported evidence suggesting that Venus is currently volcanically active, specifically the detection of [[olivine]], a volcanic product that would weather quickly on the planet's surface.<ref name="NYT-20200109"/><ref name="SCI-20200103"/>

This massive volcanic activity is fuelled by a hot interior, which models say could be explained by energetic collisions when the planet was young, as well as [[radioactive decay]] as in the case of the earth. Impacts would have had significantly higher velocity than on Earth, both because Venus moves faster due to its closer proximity to the Sun and because high-eccentricity objects colliding with the planet would have high speeds.<ref>{{Cite web |url=https://www.sci.news/space/venus-volcanism-12114.html |title=Early, Energetic Collisions Could Have Fueled Venus Volcanism: Study {{!}} Sci.News |date=20 July 2023 |access-date=21 July 2023 |archive-date=21 July 2023 |archive-url=https://web.archive.org/web/20230721193015/https://www.sci.news/space/venus-volcanism-12114.html |url-status=live }}</ref>

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]],<ref name="USGS_Ganis_Chasma"/>{{refn|group=note|Misstated as "Ganiki Chasma" in the press release and scientific publication.<ref name = "Lakdawalla2015"/>}} 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.<ref name="Lakdawalla2015"/><ref name="ESA_2015-06-18"/> 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 {{convert|800|-|1100|K|C F}} range, relative to a normal temperature of {{convert|740|K|C F}}.<ref name="Shalygin2015"/> In 2023, scientists reexamined topographical images of the Maat Mons region taken by the ''[[Magellan (spacecraft)|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.<ref>{{cite web | title=Why the Discovery of an Active Volcano on Venus Matters | last=Kluger | first=Jeffrey | url=https://time.com/6264160/why-volcanoes-on-venus-matter/ | publisher=[[Time (magazine)|Time]] | date=17 March 2023 | access-date=19 March 2023 | archive-date=19 March 2023 | archive-url=https://web.archive.org/web/20230319022005/https://time.com/6264160/why-volcanoes-on-venus-matter/ | url-status=live }}</ref>

==== Craters ====
[[File:PIA00103 Venus - 3-D Perspective View of Lavinia Planitia.jpg|thumb|upright=0.9|alt=The plains of Venus|[[Impact crater]]s on the surface of Venus (false-colour, [[3D projection]] image reconstructed from radar data)]]

There are almost a thousand impact craters on Venus, 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{{spaces}}million years ago,<ref name="Nimmo98" /><ref name="Strom1994"/> followed by a decay in volcanism.<ref name=Romeo_Turcotte_2018/> 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{{spaces}}million years, subduction occurs on an enormous scale, completely recycling the crust.<ref name="Frankel" />

Venusian craters range from {{convert|3|to|280|km|mi|0|abbr=on}} in diameter. No craters are smaller than 3{{spaces}}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.<ref name=Herrick_Phillips_1993/> Incoming projectiles less than {{convert|50|m|ft|-1|abbr=on}} in diameter will fragment and burn up in the atmosphere before reaching the ground.<ref name=Morrison_Owens_2003/>

=== Internal structure ===
[[File:InteriorOfVenus.svg|thumb|upright=1.05|The [[Planetary differentiation|differentiated]] structure of Venus|alt=Spherical cross-section of Venus showing the different layers]]

Without data from [[reflection seismology]] or knowledge of its [[moment of inertia]], little direct information has been available about the internal structure and [[geochemistry]] of Venus.<ref name="goettel"/> The similarity in size and density between Venus and Earth suggests that they share a similar internal structure: a [[Planetary core|core]], [[Mantle (geology)|mantle]], and [[Crust (geology)|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,<ref name=Faure_Mensing_2007/> although a completely solid core cannot be ruled out.<ref name=Dumoulin2017/> The slightly smaller size of Venus means pressures are 24% lower in its deep interior than Earth's.<ref name=Aitta_2016/> The predicted values for the moment of inertia based on planetary models suggest a core radius of 2,900–3,450&nbsp;km.<ref name=Dumoulin2017/> There is now an estimate of 3,500&nbsp;km from the [[moment of inertia]] based on the rate of [[axial precession]], measured between 2006 and 2020.<ref name=Margot_et_al_2021/><ref name="O'Callaghan_2021"/>

The crust of Venus is estimated to be 40 kilometers thick on average and at most 65 kilometers thick.<ref>{{Cite journal |last1=Semprich |first1=Julia |last2=Filiberto |first2=Justin |last3=Weller |first3=Matthew |last4=Gorce |first4=Jennifer |last5=Clark |first5=Nolan |date=2025-03-25 |title=Metamorphism of Venus as driver of crustal thickness and recycling |journal=Nature Communications |language=en |volume=16 |issue=1 |page=2905 |doi=10.1038/s41467-025-58324-1 |pmid=40133342 |bibcode=2025NatCo..16.2905S |issn=2041-1723|pmc=11937330}}</ref>

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]].<ref name="Nimmo_2002"/> Instead, Venus may lose its internal heat in periodic major resurfacing events.<ref name="Nimmo98"/>

=== Magnetic field and core ===
[[File:Venusian magnetosphere.svg|thumb|Venus interacts with the solar wind. Components of the induced magnetosphere are shown.]]
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]],<ref name="Eroshenko_et_al_1969"/><ref name="Kivelson_Russell_1995"/>{{Page needed|date=January 2023}} rather than by an internal [[dynamo theory|dynamo]] as in the Earth's [[Planetary core|core]]. [[Magnetosphere of Venus|Venus's small induced magnetosphere]] provides negligible protection to the atmosphere against [[solar radiation|solar]] and [[cosmic radiation]].

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 [[Electrical conductor|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.<ref name="Luhmann_Russell_2006"/><ref name=Stevenson_2003/> 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 [[Thermal insulation|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.<ref name="nimmo02"/>

One possibility is that Venus has no solid inner core,<ref name="Konopliv_Yoder_1996"/> 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 dependent on the concentration of [[sulphur]], which is unknown at present.<ref name="nimmo02" />

Another possibility is that the absence of a 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".<ref name="Jacobsen2017">{{cite journal | last1=Jacobson | first1=Seth A. | last2=Rubie | first2=David C. | last3=Hernlund | first3=John | last4=Morbidelli | first4=Alessandro | last5=Nakajima | first5=Miki | title=Formation, stratification, and mixing of the cores of Earth and Venus | journal=Earth and Planetary Science Letters | publisher=Elsevier BV | volume=474 | year=2017 | doi=10.1016/j.epsl.2017.06.023 | page=375| arxiv=1710.01770 | bibcode=2017E&PSL.474..375J | s2cid=119487513 }}</ref>

The weak magnetosphere around Venus means that the solar wind interacts directly with its outer atmosphere. Here, ions of hydrogen and oxygen are being created by the [[Dissociation (chemistry)|dissociation]] of water molecules due to [[ultraviolet]] radiation. The solar wind then supplies energy that gives some of these ions sufficient speed 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.<ref name="nature450_7170_629"/> However, the planet may have retained a dynamo for its first 2–3 billion years, so the water loss may have occurred more recently.<ref name="O'Rourke_et_al_2019"/> 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.<ref name="Donahue_et_al_1982"/>

== Atmosphere and climate ==
{{Main|Atmosphere of Venus}}
{{Further|Extraterrestrial sky#Venus}}
[[File:Venus - December 23 2016.png|alt=The atmosphere of Venus appears darker and lined with shadows. The shadows trace the prevailing wind direction.|thumb|upright=0.9|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<ref name="u3r1a"/>—and traces of other gases including [[sulphur dioxide]].<ref name="SolarSystemEncyclopedia"/> 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 {{convert|1|km|mi|frac=8|abbr=on}} under Earth's ocean surfaces. The density at the surface is {{Convert|65|kg/m3|lb/ft3|abbr=on}}, 6.5% that of water<ref name="u3r1a"/> or 50 times as dense as Earth's atmosphere at {{convert|20|C|K C F|0|order=out}} at sea level. The {{chem2|CO2}}-rich atmosphere generates the strongest [[greenhouse effect]] in the Solar System, creating surface temperatures of at least {{convert|462|C|K C F|order=out}}.<ref name="nasa_venus" /><ref name=CWRU_2006/> This makes the Venusian surface hotter than [[Mercury (planet)|Mercury]]'s, which has a minimum surface temperature of {{convert|−220|C|K C F|0|order=out|round=5}} and maximum surface temperature of {{convert|427|C|K C F|0|order=out|round=5}},<ref name=Lewis_2004/><ref name=Prockter_2005/> even though Venus is nearly twice Mercury's distance from the Sun and thus receives only around a quarter of Mercury's solar [[irradiance]], of 2,600 W/m<sup>2</sup> (double that of Earth).<ref name="fact" /> 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.<ref name="Newitz 2013"/> Therefore Venus has been called a greenhouse planet,<ref name="a490">{{cite conference | last=Landis | first=Geoffrey A. | title=AIP Conference Proceedings | chapter=Colonization of Venus | publisher=AIP | volume=654 | date=2003 | page= | doi=10.1063/1.1541418 | pages=1193–1198}}</ref> a planet under a greenhouse inferno.<ref name="p181">{{cite web | last=Querol | first=Ricardo de | title='Cosmos': Carl Sagan was right (and we didn't pay much attention to him) | website=EL PAÍS English | date=April 28, 2023 | url=https://english.elpais.com/opinion/2023-04-28/cosmos-carl-sagan-was-right-and-we-didnt-pay-much-attention-to-him.html | access-date=March 12, 2025}}</ref>

{|class="wikitable floatleft" style="font-size: 100%; margin-right: 1em;"
|+ Venus temperature<ref name=Weather/> 
|-
! Type || Surface<br />temperature
|-
| Maximum || 900&nbsp;°F (482&nbsp;°C)
|-
| Normal || 847&nbsp;°F (453&nbsp;°C)
|-
| Minimum || 820&nbsp;°F (438&nbsp;°C)
|}

Venus's atmosphere is rich in primordial [[noble gas]]es compared to that of Earth.<ref name=Halliday_2020/> This enrichment indicates an early divergence from Earth in evolution. An unusually large comet impact<ref name=Owen_et_al_1992/> or accretion of a more massive [[primary atmosphere]] from the solar nebula<ref name=Pepin_1991/> have been proposed to explain the enrichment. However, the atmosphere is poor in radiogenic [[argon-40]], a proxy for mantle degassing, suggesting an early shutdown of major magmatism.<ref name=Namiki_Solomon_1998/><ref name="O'Rurke_Korenaga_2015"/>

Studies have suggested that billions of years ago, the atmosphere of Venus may have been much more like the one surrounding the early Earth, and there may have been substantial quantities of liquid water on the surface.<ref name="Ernst 2022"/><ref name="Way Del Genio 2020 p."/><ref name="Way Del Genio Kiang Sohl 2016 pp. 8376–8383"/> After a period of 600 million to several billion years,<ref name="baas39_540"/> the rising luminosity of the Sun and possibly [[Large igneous province|large volcanic resurfacing]] caused the evaporation of the original water.<ref name="Steigerwald 2022"/> A runaway greenhouse effect was created once a critical level of greenhouse gases (including water) was reached in the atmosphere.<ref name="Kasting"/> Although the surface conditions on Venus are no longer hospitable to any terrestrial-like life that might have formed before this event, there is speculation that life may exist in the upper cloud layers of Venus, {{convert|50|km|mi|sigfig=1|abbr=on}} above the surface, where atmospheric conditions are the most Earth-like in the Solar System,<ref name="Tillman 2018"/> with temperatures ranging between {{convert|30|and|80|C|K C F|order=out}}, and the pressure and radiation being about the same as at Earth's surface, but with acidic clouds and the carbon dioxide air.<ref name=Mullen_2002/><ref name=Landis_2003/><ref name="Cockell1999"/> More specifically, between heights of 48 and 59&nbsp;km temperature and radiation conditions are suitable for life. At lower elevations water would evaporate and at higher elevation UV radiation would be too strong.<ref name="Patel Mason Nordheim Dartnell 2022 p=114796">{{cite journal |last1=Patel |first1=M.R. |last2=Mason |first2=J.P. |last3=Nordheim |first3=T.A. |last4=Dartnell |first4=L.R. |year=2022 |title=Constraints on a potential aerial biosphere on Venus: II. Ultraviolet radiation |url=https://oro.open.ac.uk/80021/9/80021VOR.pdf |journal=Icarus |publisher=Elsevier BV |volume=373 |article-number=114796 |bibcode=2022Icar..37314796P |doi=10.1016/j.icarus.2021.114796 |issn=0019-1035 |s2cid=244168415 |doi-access=free}}</ref><ref name="Herbst Banjac Atri Nordheim 2019 p=A15">{{cite journal |last1=Herbst |first1=Konstantin |last2=Banjac |first2=Saša |last3=Atri |first3=Dimitra |last4=Nordheim |first4=Tom A. |date=24 December 2019 |title=Revisiting the cosmic-ray induced Venusian radiation dose in the context of habitability |journal=Astronomy & Astrophysics |publisher=EDP Sciences |volume=633 |page=A15 |arxiv=1911.12788 |bibcode=2020A&A...633A..15H |doi=10.1051/0004-6361/201936968 |issn=0004-6361 |s2cid=208513344}}</ref> 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.<ref name=Drake_2020/><ref name=Greaves_et_al_2020/> Later research attributed the spectroscopic signal that was interpreted as phosphine to sulphur dioxide,<ref name=Lincowski_et_al_2021/> or found that in fact there was no absorption line.<ref name=Beall_2020/><ref name=Snellan_et_al_2020/>

[[File:11214 2023 956 Fig6 HTML.webp|thumb|upright=0.8|Atmospheric profile by altitude (left scale): cloud layers, temperature change (''VIRA'' thick line and bottom scale), pressure change (right scale) and wind speed (''PV'' dotted lines and top scale)]]

[[Thermal inertia]] and the transfer of heat by winds in the lower atmosphere mean that the surface temperature does not vary significantly between the hemispheres 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.<ref name=Moshkin_et_al_1979/>

Above the dense {{chem2|CO2}} layer are thick clouds 45 to 70&nbsp;km above the surface,<ref>{{cite web |title=New details on venusian clouds revealed |url=https://www.esa.int/Science_Exploration/Space_Science/Venus_Express/New_details_on_venusian_clouds_revealed |publisher=European Space Agency |date=2008}}</ref> consisting mainly of [[sulphuric acid]], which is formed by a reaction catalyzed by UV radiation from sulphur dioxide molecules and then water,<ref>{{cite web |title=Acid clouds and lightning |url=https://www.esa.int/Science_Exploration/Space_Science/Venus_Express/Acid_clouds_and_lightning |publisher=European Space Agency}}</ref> resulting in sulphuric acid hydrate.<ref>{{cite journal |last1=M.L. Delitsky and K.H. Baines |title=Chemistry in the Venus clouds: Sulfuric acid reactions and freezing behavior of aqueous liquid droplets |journal=AAS/Division for Planetary Sciences Meeting Abstracts #47 |url=https://ui.adsabs.harvard.edu/abs/2015DPS....4721702D/abstract |publisher=American Astronomical Society |date=Nov 2015|volume=47 |bibcode=2015DPS....4721702D }}</ref> Additionally, the clouds contain approximately 1% [[ferric chloride]].<ref name="kras006"/><ref name=Krasnopolsky_2006/> 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.<ref name="kras006"/> These clouds reflect, like thick cloud cover on Earth, about 70% of the sunlight that falls on them back into space,<ref name="Davis 2021"/> and since they cover the whole planet they prevent visual observation of the 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,<ref name="ESA Blog Navigator – Navigator page for active ESA blogs 2012"/> 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"<ref name=sci_news_1976/>.

Venus's atmosphere rotates much faster than its solid body, a phenomenon known as atmospheric [[Atmospheric_super-rotation|super-rotation]].<ref>{{Cite journal |last1=Sánchez-Lavega |first1=Agustín |last2=Lebonnois |first2=Sebastien |last3=Imamura |first3=Takeshi |last4=Read |first4=Peter |last5=Luz |first5=David |date=November 2017 |title=The Atmospheric Dynamics of Venus |url=http://link.springer.com/10.1007/s11214-017-0389-x |journal=Space Science Reviews |language=en |volume=212 |issue=3–4 |pages=1541–1616 |doi=10.1007/s11214-017-0389-x |issn=0038-6308|url-access=subscription }}</ref> This results in strong {{convert|300|km/h|mph|round=5|abbr=on}} winds at the cloud tops, which complete a full rotation around the planet in about 4 days, corresponding to 60 times the speed of the planet's rotation<ref name=Rossow_et_al_1990/>, whereas Earth's strongest winds reach only 10–20% of its rotational speed.

Although Venus looks featureless in visible light, there are bands or streaks in the UV, whose origin has not been pinned down. The absorption of UV may be due to a compound of oxygen and sulfur, OSSO, which has a double bond between the sulfur atoms and exists in "cis" and "trans" forms, or due to polysulfur compounds from {{chem2|S2}} to {{chem2|S8}}.<ref>{{cite journal |display-authors=etal|last1=Antonio Francés-Monerris |title=Photochemical and thermochemical path- ways to S{{sub|2}} and polysulfur formation in the atmosphere of Venus |journal=Nature Communications |date=Jul 30, 2022 |volume=13 |issue=1 |article-number=4425 |doi=10.1038/s41467-022-32170-x|pmid=35907911 |pmc=9338966 }}</ref>

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.<ref name="fact"/><ref name=Lorenz_et_al_2001/> Venus's minute [[axial tilt]]—less than 3°, compared to 23° on Earth—also minimizes seasonal temperature variation.<ref name=NASA_Seasons/> Altitude is one of the few factors that affect Venusian temperatures. The highest point on Venus, [[Skadi Mons]] of the [[Maxwell Montes]] range, is therefore the coolest point on Venus, with a temperature of about {{convert|380|C|K C F|order=out|round=5}} and an atmospheric pressure of about {{convert|45|bar|MPa|abbr=on|order=flip}}.<ref name="Basilevsky_2003"/><ref name="McGill_2010"/> In 1995, the [[Magellan (spacecraft)|''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 by 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]]).<ref name=Otten_2004/>

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]].<ref name="TAJ-20190826"/>

The existence of lightning in the atmosphere of Venus has been controversial<ref name="Lorentz_2018"/> since the first suspected bursts were detected by the Soviet [[Venera|Venera probes]].<ref name="Kranopol'skii_1980"/><ref name="Russell, Philips"/><ref name=Venera_12/> In 2006–07, ''[[Venus Express]]'' clearly detected [[Electromagnetic electron wave#R wave and L wave|whistler mode waves]], the signatures of lightning. Their [[wikt:intermittent|intermittent]] appearance indicates a pattern associated with weather activity. According to these measurements, the lightning rate is at least half that on Earth,<ref name="Russell_2007"/> however other instruments have not detected lightning at all.<ref name="Lorentz_2018" /> The origin of any lightning remains unclear, but could originate from clouds or [[Volcanism on Venus|Venusian volcanoes]].

In 2007, ''Venus Express'' discovered that a huge double [[Polar vortex|atmospheric polar vortex]] exists at the south pole.<ref name=Hand_2007/><ref name=BBC_2007_11_28/> ''Venus Express'' discovered, in 2011, that an [[ozone]] layer exists high in the atmosphere of Venus.<ref name="esaozone"/> In 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."<ref name="ESA-20130129"/><ref name="Space-20130130"/>

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 wave]]s in the solar system.<ref name=Fukuhara_et_al_2017/><ref name=Rincon_2017/><ref name=Chang_2017/>

Colour and sound<ref name="l172">{{cite web | title=Venera 14 : Soviet Academy of Sciences : Free Download, Borrow, and Streaming: Internet Archive | website=Internet Archive | date=October 23, 2016 | url=https://archive.org/details/venera-14-venus-recording | access-date=June 2, 2025}}</ref> of the atmosphere at the surface have been recorded, with [[Extraterrestrial sky#Venus|the sky]] having an orange-yellow colour, while at higher altitudes being white.<ref name="t069">{{cite journal |last1=Moroz |first1=V. I. |last2=Golovin |first2=Yu. M. |last3=Ekonomov |first3=A. P. |last4=Moshkin |first4=B. E. |last5=Parfent'ev |first5=N. A. |last6=San'ko |first6=N. F. |title=Spectrum of the Venus day sky |journal=Nature |volume=284 |issue=5753 |date=1980 |issn=0028-0836 |doi=10.1038/284243a0 |pages=243–244 |bibcode=1980Natur.284..243M |url=https://www.nature.com/articles/284243a0 |url-access=subscription |access-date=June 2, 2025}}</ref>

== Orbit and rotation ==
{{Main|Orbit of Venus}}
[[File:Solar system orrery inner planets.gif|alt=Mars circling the Sun further and slower than Earth|thumb|upright=1.1|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 {{convert|0.72|AU|e6km+e6mi|abbr=unit|lk=on}}, and completes an orbit every 224.7 days. It completes 13 orbits in 7.998 years, so its position in our sky almost repeats every eight years. Although all planetary [[orbit]]s are [[ellipse|elliptical]], Venus's orbit is currently the closest to circular, with an [[Orbital eccentricity|eccentricity]] of less than 0.01.<ref name="fact" /> 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.<ref name="psj_1_42"/>

[[File:11214 2023 956 Fig7 HTML.webp|thumb|upright=1.1|Venus and its rotation in respect to its revolution]]

Venus has [[retrograde rotation]], meaning that unlike most planets including Earth it rotates clockwise around its own axis, opposite to its [[anticlockwise]] rotation around the Sun.
Therefore Venusian [[sidereal day]], 243 Earth days,  lasts longer than a Venusian year, 224.7 Earth days.
If Venus were [[tidal lock|tidally locked]] to the Sun, it would always have the same face pointed to the Sun and its sidereal day would be 224.7 days. However, Venus's atmosphere is massive and it is close to the Sun, so differential heating of the atmosphere gives Venus a small retrograde rotation. The day length also fluctuates 
by up to 20 minutes for the same reason.<ref name="EarthSky Updates on your cosmos and world 2021">{{cite web | title=The length of a day on Venus is always changing – Space | website=EarthSky | date=5 May 2021 | url=https://earthsky.org/space/venus-length-of-day-spin-rate-axial-tilt-radio-waves/ | access-date=28 April 2023 | archive-date=28 April 2023 | archive-url=https://web.archive.org/web/20230428232110/https://earthsky.org/space/venus-length-of-day-spin-rate-axial-tilt-radio-waves/ | url-status=live }}</ref><ref>{{Cite journal |last1=Margot |first1=Jean-Luc |last2=Campbell |first2=Donald B. |last3=Giorgini |first3=Jon D. |last4=Jao |first4=Joseph S. |last5=Snedeker |first5=Lawrence G. |last6=Ghigo |first6=Frank D. |last7=Bonsall |first7=Amber |date=2021-04-29 |title=Spin state and moment of inertia of Venus |url=https://www.nature.com/articles/s41550-021-01339-7 |journal=Nature Astronomy |language=en |volume=5 |issue=7 |pages=676–683 |doi=10.1038/s41550-021-01339-7 |issn=2397-3366|arxiv=2103.01504 |bibcode=2021NatAs...5..676M }}</ref>  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{{spaces}}minutes.<ref name="slowing spin"/> 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.<ref name="planetary-facts"/>
One Venusian year is about 1.92{{spaces}}Venusian solar days.<ref name="compare"/> To an observer on the surface of Venus, the Sun would rise in [[Poles of astronomical bodies|the west]] and set in the east,<ref name="compare" /> although Venus's opaque clouds prevent observing the Sun from the planet's surface.<ref name="Brunier_2002"/>

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 [[tide|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.<ref name="Correia_et_al_2003"/><ref name="Laskar_De_Surgy_2003"/> The 584-day average interval between successive close approaches to Earth is almost exactly equal to 5{{spaces}}Venusian solar days (5.001444 to be precise),<ref name="Gold_Soter_1969"/> but the hypothesis of a spin-orbit resonance with Earth has been discounted.<ref name="apj2_230_L123"/>

Venus has no natural satellites.<ref name="icarus202"/> It has several [[trojan asteroid]]s: the [[quasi-satellite]] {{mpl|524522 Zoozve}}<ref name="Mikkola_et_al_2004"/><ref name="Carlos_De_la_Fuente_Marcos_2012"/> and two other temporary trojans, {{mpl-|322756|2001 CK|32}} and {{mpl|2012 XE|133}}.<ref name="dynamics"/> In the 17th century, [[Giovanni Cassini]] reported a moon orbiting Venus, which was named [[Neith (hypothetical moon)|Neith]] and numerous sightings were reported over the following {{val|200|u=years}}, but most were determined to be stars in the vicinity. Alex Alemi's and [[David J. Stevenson|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.<ref name="Musser_2006"/> About 10{{spaces}}million{{spaces}}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.<ref name="Tytell_2006"/> 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.<ref name="icarus202" />

The orbital space of Venus has a [[interplanetary dust#Rings of dust|dust ring-cloud]],<ref name="Frazier 2021"/> with a suspected origin either from Venus–trailing asteroids,<ref name="Garner 2019"/> interplanetary dust migrating in waves, or the remains of the Solar System's original [[circumstellar disc]] that formed the [[planetary system]].<ref name="Rehm 2021"/>

=== Orbit in respect to Earth ===
[[File:Venus pentagram.png|thumb|Earth is positioned at the centre of the diagram, and the curve represents the direction and distance of Venus as a function of time.|alt=A complex, spiral, floral pattern with five loops encircling the middle]]

Earth and Venus have a near [[orbital resonance]] of 13:8 (Earth orbits eight times for every 13 orbits of Venus).<ref name="Bazsó">{{cite journal |last1=Bazsó |first1=A. |last2=Eybl |first2=V. |last3=Dvorak |first3=R. |last4=Pilat-Lohinger |first4=E. |last5=Lhotka |first5=C. |year=2010 |title=A survey of near-mean-motion resonances between Venus and Earth |journal=[[Celestial Mechanics and Dynamical Astronomy]] |volume=107 |issue=1 |pages=63–76 |arxiv=0911.2357 |bibcode=2010CeMDA.107...63B |doi=10.1007/s10569-010-9266-6|s2cid=117795811 }}</ref>
Therefore, they approach each other and reach [[inferior conjunction]] in [[synodic period]]s of 584 days, on average.<ref name="fact" /> The path that Venus makes in relation to Earth viewed geocentrically draws a [[Pentagram#Pentagram of Venus|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.<ref name=Ottewel_2022/>

When Venus lies between Earth and the Sun in [[Conjunction (astronomy)#Superior and inferior|inferior]] conjunction, it makes the closest approach to Earth of any planet at an average distance of {{convert|41|e6km|e6mi|abbr=unit}}.<ref name="fact" />{{refn|group=note
|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.<ref name="MoreOrLess" />
}}<ref name="MoreOrLess"/>
Because of the [[Milankovitch cycles#Orbital eccentricity|decreasing eccentricity of Earth's orbit]], the minimum distances will become greater over tens of thousands of years. From the year{{spaces}}1 to 5383, there are 526 approaches less than {{convert|40|e6km|e6mi|abbr=unit}}; then, there are none for about 60,158 years.<ref name="Solex11"/>

While Venus approaches Earth the closest, Mercury is more often the closest to Earth of all planets and to any other planet.<ref name="AIP Publishing 2019 p."/><ref>{{cite magazine |title= Venus is not Earth's closest neighbour {{!}} Calculations and simulations confirm that on average, Mercury is the nearest planet to Earth-and to every other planet in the solar system. |magazine=Physics Today |doi=10.1063/PT.6.3.20190312a |first1=Tom |last1=Stockman |first2=Gabriel |last2=Monroe |first3=Samuel |last3=Cordner |date=2019 |publisher=American Institute of Physics}}</ref> Venus has been used as a waypoint for [[gravity assist]] maneuvers, which has been identified as a faster and economic way to travel to Mercury,<ref>{{Cite journal |last=Yen |first=C.-W. L. |date=August 1986 |title=Ballistic Mercury orbiter mission via Venus and Mercury gravity assists. |url=https://ui.adsabs.harvard.edu/abs/1986asdy.conf.1293Y/abstract |journal=Astrodynamics 1985 |language=en |pages=1293–1308 |bibcode=1986asdy.conf.1293Y }}</ref><ref>{{Cite journal |last1=Sturms |first1=Francis M. |last2=Cutting |first2=Elliott |date=May 1966 |title=Trajectory analysis of a 1970 mission to Mercury via a close encounter with Venus. |url=https://arc.aiaa.org/doi/10.2514/3.28505 |journal=Journal of Spacecraft and Rockets |volume=3 |issue=5 |pages=624–631 |doi=10.2514/3.28505 |issn=0022-4650|url-access=subscription }}</ref> the Sun,<ref>{{Cite web |date=2018-10-04 |title=Parker Solar Probe Changed the Game Before it Even Launched - NASA |url=https://www.nasa.gov/solar-system/parker-solar-probe-changed-the-game-before-it-even-launched/ |access-date=2025-06-23 |language=en-US}}</ref> asteroids,<ref>{{Cite web |title=IV-1 |url=https://nss.org/settlement/nasa/spaceres/IV-1.html |access-date=2025-06-22 |website=nss.org}}</ref> Mars,<ref>{{Cite journal |last1=Izenberg |first1=Noam R. |last2=McNutt |first2=Ralph L. |last3=Runyon |first3=Kirby D. |last4=Byrne |first4=Paul K. |last5=MacDonald |first5=Alexander |date=2021-03-01 |title=Venus Exploration in the New Human Spaceflight Age |journal=Acta Astronautica |volume=180 |pages=100–104 |doi=10.1016/j.actaastro.2020.12.020 |bibcode=2021AcAau.180..100I |issn=0094-5765|doi-access=free }}</ref> Jupiter and beyond.<ref name="Petropoulos Longuski Bonfiglio 2000 pp. 776–783"/><ref name="Taylor 2020"/>

Tidally Venus exerts the third strongest [[tidal force]] on Earth, after the Moon and the Sun, though significantly less.<ref name="Science Mission Directorate 2000">{{cite web | title=Interplanetary Low Tide | website=Science Mission Directorate | date=3 May 2000 | url=https://science.nasa.gov/science-news/science-at-nasa/2000/ast04may_1m | access-date=25 June 2023 | archive-date=4 June 2023 | archive-url=https://web.archive.org/web/20230604014510/https://science.nasa.gov/science-news/science-at-nasa/2000/ast04may_1m  }}</ref>

== Observability ==
[[File:Venus-pacific-levelled.jpg|thumb|alt=A photograph of the night sky taken from the seashore. A glimmer of sunlight is on the horizon. There are many stars visible. Venus is at the centre, much brighter than any of the stars, and its light can be seen reflected in the ocean.|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 with a maximum [[apparent magnitude]] of −4.92 brighter than any other planet or star apart from the Sun,<ref name=Dickinson_1998/> even when faintest during [[Transit of Venus|its transit]] with an apparent magnitude of −2.98.<ref name="Mallama_and_Hilton" />  The planet's mean apparent magnitude is −4.14 with a standard deviation of 0.31.<ref name="Mallama_and_Hilton" /> 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, although the exact value depends on the [[Phase angle (astronomy)|phase angle]].<ref name="n850">{{cite web | title=Start watching for Venus brightest in the morning sky | website=[[Earth & Sky]] | date=15 April 2025 | url=https://earthsky.org/astronomy-essentials/venus-brightest-greatest-brilliancy-greatest-illuminated-extent-2/ | access-date=21 April 2025}}</ref> The planet is bright enough to be seen in broad daylight,<ref name="Flanders_2011"/> 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]].<ref name="ephemeris"/>

Venus "overtakes" Earth every 584 days as it orbits the Sun.<ref name="fact" /> 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]]".<ref name=ASP_2021/>

Because Venus comes close to the earth at [[inferior conjunction]] and has an orbit inclined to the plane of the earth's orbit, it can appear more than 8° north or south of the [[ecliptic]], more than any other planet or the moon. Every eight years around March it appears this far north of the ecliptic, in [[Pisces (constellation)|Pisces]] (such as in mid-March 2025), and every eight years it appears this far south of the ecliptic in August or September in [[Virgo (constellation)|Virgo]] (as in late August 2023). Venus can thus be north of the sun and appear as a morning star and an evening star on the same day, in the northern hemisphere. The timing of these north or south excursions  gets slowly earlier in the year, and over 30 cycles (240 years) the cycle is gradually replaced by another cycle offset by three years, so the situation returns close to the original situation after 243 orbits of Earth, 395 of Venus.<ref>See [https://ssd.jpl.nasa.gov/api/horizons.api?format=text&COMMAND=299&START_TIME=%272000-1-21%2015:51:57%27&STOP_TIME=%272104-4-15%2013:23:31%27&STEP_SIZE=2798&QUANTITIES=31 this JPL Horizons ephemeris calculation].</ref>

[[Lunar occultation of Venus|Lunar occultations of Venus]], in which the moon blocks the view of Venus for observers in certain parts of the earth, occur on average about twice a year, sometimes several times in a year (though rarely).

=== Phases ===
{{Main|Phases of Venus}}
[[File:Phases Venus.jpg|thumb|The phases of Venus and evolution of its apparent diameter|alt=Diagram illustrating the phases of Venus]]

As it orbits the Sun, Venus displays [[phases of Venus|phases]] like those of the [[Moon]] in a [[optical telescope|telescopic]] view. The planet appears as a small and "full" disc when it is on the opposite side of the Sun (at superior [[conjunction (astronomy)|conjunction]]). Venus shows a larger disc and "quarter phase" at its maximum [[Elongation (astronomy)|elongation]]s 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.<ref name="ephemeris" /> The phases are clearly visible in a 4" telescope.<ref>{{Cite web |last=Lavender |first=Gemma |date=26 March 2023 |title=What equipment do you need to see and photograph the planets |url=https://www.space.com/what-equipment-do-you-need-to-see-and-photograph-the-planets |access-date=5 June 2024 |website=Space.com |language=en}}</ref> Although naked eye visibility of Venus's phases is disputed, records exist of observations of its crescent.<ref name="Goines_1995" />

=== Daylight apparitions ===
[[File:Lunar Occultation of Venus (NHQ201512070001).jpg|alt=venus next to a crescent moon in the blue daytime sky|thumb|Venus is often visible to the naked eye in daytime, as seen just prior to the lunar occultation of 7 December 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.<ref>{{Cite web |title=Viewing Venus in Broad Daylight |url=https://www.fourmilab.ch/images/venus_daytime/ |access-date=17 July 2023 |website=www.fourmilab.ch |archive-date=15 November 2021 |archive-url=https://web.archive.org/web/20211115012816/https://www.fourmilab.ch/images/venus_daytime/ |url-status=live }}</ref> 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]].<ref name="Chatfield_2015" /> Another historical daytime observation of the planet took place during the inauguration of the American president [[Abraham Lincoln]] in Washington, D.C., on 4{{spaces}}March 1865.<ref name="Gaherty_2012" />

=== Transits ===
{{Main|Transit of Venus}}
[[File:Transit of Venus viewed in Wagga Wagga (2).jpg|alt=White disk with a small black dot projected on a screen|left|thumb|upright=0.75|[[2012 transit of Venus]], projected by a [[telescope]] onto a white card]]

A [[transit (astronomy)|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. Consequently, Venus transits only occur when an inferior conjunction takes place during some days of June or December, when the orbits of Venus and Earth cross a straight line with the Sun.<ref name="NASA 2004">{{cite web | title=2004 and 2012 Transits of Venus | website=NASA | date=8 June 2004 | url=https://eclipse.gsfc.nasa.gov/transit/venus0412.html#:~:text=Transits%20of%20Venus%20are%20only,121.5%2C%208%20and%20105.5%20years. | access-date=2 May 2023 | archive-date=2 May 2023 | archive-url=https://web.archive.org/web/20230502134029/https://eclipse.gsfc.nasa.gov/transit/venus0412.html#:~:text=Transits%20of%20Venus%20are%20only,121.5%2C%208%20and%20105.5%20years. | url-status=live }}</ref> This results in Venus transiting above Earth in a sequence currently of {{val|8|u=years}}, {{val|105.5|u=years}}, {{val|8|u=years}} and {{val|121.5|u=years}}, forming cycles of {{val|243|u=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 [[Transit of Venus, 1639|1639 with the first known observation]] of a Venus transit (after history's first observed planetary [[Transit of Mercury|transit in 1631, of Mercury]]).<ref name=Kollerstrom_1998/>

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.<ref name=Hornsby_1771/><ref name=Woolley_1969/>

The latest pair was [[Transit of Venus, 2004|June 8, 2004]] and [[Transit of Venus, 2012|June 5–6, 2012]]. The transit could be watched live from many online outlets or observed locally with the right equipment and conditions.<ref name=Boyle_2016/> The preceding pair of transits occurred in [[Transit of Venus, 1874|December 1874]] and [[Transit of Venus, 1882|December 1882]].

The next transit will occur in December 2117 and December 2125.<ref name=Espenak_2004/>

=== Ashen light ===
[[File:Venus-ParkerSolarProbe-July2020.jpg|thumb|[[Nightglow]] is since 2022 considered the most likely candidate for the ashen light. In this visible light near-infrared image it is most discernable as a bright line along the limb of Venus.<ref name="e367">{{cite web | last=Dobbins | first=Thomas A. | title=The Parker Solar Probe Captures Surprising Images of Venus Nightside | website=Sky & Telescope | date=2022-02-22 | url=https://skyandtelescope.org/astronomy-news/the-parker-solar-probe-captures-surprising-images-of-venus-nightside/ | access-date=2025-03-14}}</ref> The surface and its features, like the visible dark patch in this image, the [[Ovda Regio]] plateau of [[Aphrodite Terra]], is much less discernable by the human eye, though reportedly seen by some people, possibly due to higher sensitivity in the spectrum that the surface glows.<ref name="n420">{{cite web | title=Nightside observations by the Parker Solar Probe: implications for the reality of the Ashen Light – British Astronomical Association | website=British Astronomical Association – Supporting amateur astronomers since 1890 | date=2024-05-21 | url=https://britastro.org/journal_contents_ite/nightside-observations-by-the-parker-solar-probe-implications-for-the-reality-of-the-ashen-light | access-date=2025-03-14}}</ref>]]

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.<ref name=Baum_2000/><ref name="Russell, Philips" /> 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|Observations and explorations of Venus}}

===Early observation===
Venus is in Earth's sky bright enough to be visible [[Naked eye|without aid]], making it one of the [[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 recognize Venus as a single entity;<ref name="Cooley"/> instead, they assumed it to be two separate stars on each horizon: the morning and evening star.<ref name=Cooley/> 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.<ref name="Sachs_1974"/><ref name=Cooley/><ref name=Hobson_2009/>

[[File:Venus Tablet of Ammisaduqa.jpg|thumb|upright=0.75|Oldest known recording of Venus positions, on the [[Babylonia]]n ''[[Venus tablet of Ammisaduqa]]'' (1600 BC)]]

In the Old [[Babylonia]]n period, the planet Venus was known as Ninsi'anna, and later as Dilbat.<ref>Enn Kasak, Raul Veede. Understanding Planets in Ancient Mesopotamia. Folklore Vol. 16. Mare Kõiva & Andres Kuperjanov, Eds. ISSN 1406-0957</ref> 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.<ref name=Heimpel_1982/>

The Chinese historically referred to the morning Venus as "the Great White" ({{transliteration|zh|Tàibái}} {{lang|zh|太白}}) or "the Opener (Starter) of Brightness" ({{transliteration|zh|Qǐmíng}} {{lang|zh|啟明}}), and the evening Venus as "the Excellent West One" ({{transliteration|zh|Chánggēng}} {{lang|zh|長庚}}).<ref name=Needham_1959/>

The ancient Greeks initially believed Venus to be two separate stars: [[Phosphorus (morning star)|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,<ref name=Pliny_1991/> while [[Diogenes Laërtius]] argued that [[Parmenides]] (early fifth century) was probably responsible for this discovery.<ref name=Berkert_1972/> 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 [[Hesperus|Vesper]],<ref name=Dobbin_2002/> 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 [[Samanid Empire|Persian]] astronomer [[Avicenna]] claimed to have observed a [[transit of Venus]] (although there is some doubt about it),<ref name="Goldstein"/> which later astronomers took as confirmation of Ptolemy's theory.<ref name=Enc_Irnica/> In the 12th century, the [[Al-Andalus|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 [[Maragheh observatory|Maragha]] astronomer [[Qotb al-Din Shirazi]], though this cannot be true as there were no Venus transits in Ibn Bajjah's lifetime.<ref name=Ansari_2002/>{{refn|group=note
|Several claims of transit observations made by mediaeval Islamic astronomers have been shown to be sunspots.<ref name="VaqueroVázquez2009"/> 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.<ref name="Kennard"/>}}

[[File:Dresden Codex p09.jpg|thumb|left|upright=0.7|The [[Pre-Columbian era|Pre-Columbian]] Mayan ''[[Dresden Codex]]'', which calculates appearances of Venus]]

===Venus and early modern astronomy===
{{multiple image
|footer=In 1610 [[Galileo Galilei]] observed with his telescope that [[Phases of Venus|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).
|width=220
|align=right
|image1 = Phases-of-Venus2.svg|
|image2 = Phases-of-Venus-Geocentric.svg|}}

When the planet was first observed with a telescope in December 1610, by the Italian physicist [[Galileo Galilei]], he found it showed [[planetary phase|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 [[Elongation (astronomy)|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, reported by Galileo in his 1613 [[Letters on Sunspots]], becoming one of the first observations to clearly contradict the Ptolemaic [[geocentric model]] that the Solar System was concentric and centred on Earth.<ref name="palmieri"/><ref name="Fegley"/>

The 1631 [[transit of Venus]], while not recorded, was the first one successfully predicted, by [[Johannes Kepler]] and his calculations, which he published in 1629. The following [[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{{spaces}}December 1639 (24 November under the [[Julian calendar]] in use at that time).<ref name="Kollerstrom"/>

[[File:Lavender - Jeremiah Horrocks (1618–1641).jpg|thumb|Twentieth century painting of [[Jeremiah Horrocks]] observing the [[1639 transit of Venus]].]]

The [[atmosphere of Venus]] was discovered in 1761 by Russian polymath [[Mikhail Lomonosov]].<ref name="Marov2004"/><ref name=Britannica/> 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.<ref name=Russell_1899/> 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 {{val|24|u=hours}} from the motions of markings on the planet's apparent surface.<ref name=Hussey_1832/>

[[File:Venus Drawing.jpg|thumb|left|upright=0.9|The "[[black drop effect]]" as recorded during the 1769 transit|alt=A hand-drawn sequence of images showing Venus passing over the edge of the Sun's disk, leaving an illusory drop of shadow behind]]

===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 [[astronomical spectroscopy|spectroscopic]] and [[ultraviolet]] observations that more of its secrets were revealed.

The first ultraviolet observations were carried out in the 1920s, when [[Frank E. Ross]] found that [[Ultraviolet photography|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 cloud]]s above it.<ref name=Ross_1928/>

It had been noted that Venus had no discernible [[oblate spheroid|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.<ref name=Martz_1934/> Later work in the 1950s showed the rotation was retrograde.

===First missions to Venus===
{{Further|List of missions to Venus}}

The first [[interplanetary spaceflight]] attempt was in 1961 when the [[Uncrewed spacecraft|robotic space probe]] ''[[Venera 1]]'' of the Soviet [[Venera]] programme flew to Venus. It lost contact en route.<ref name="mitchell_1"/>

The first successful interplanetary mission, also to Venus, was ''[[Mariner 2]]'' of the United States' [[Mariner program]]me, passing on 14 December 1962 at {{convert|34833|km|mi|abbr=on}} above the surface of Venus and gathering data on the planet's atmosphere.<ref name=Mayer_et_al_1958/><ref name=NASA_1962/>

Additionally [[Radar astronomy|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.<ref name=Goldstein_Carpenter_1963/>

''[[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 {{cvt|500|C|||}}, determined that the atmosphere was 95% carbon dioxide ({{chem|C|O|2}}), and discovered that Venus's atmosphere was considerably denser than ''Venera 4''{{'s}} designers had anticipated.<ref name="mitchell_2"/><ref name=Harvey115>{{cite book |last=Harvey |first=Brian |date=2007 |title=Russian Planetary Exploration History, Development, Legacy and Prospects  |publisher=Springer-Praxis |pages=115–118 |isbn=978-0-387-46343-8 }}</ref>

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.<ref name=COSPAR_Group_VII_1969/>

On 15 December 1970, ''[[Venera 7]]'' became the first spacecraft to [[Landings on other planets|soft land on another planet]] and the first to transmit data from there back to Earth.<ref name=Time_1971/>

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 {{convert|300|m|ft|sigfig=1|abbr=on}} radio telescope at [[Arecibo Observatory]], and the echoes revealed two highly reflective regions, designated the [[Alpha Regio|Alpha]] and [[Beta Regio|Beta]] regions. The observations revealed a bright region attributed to mountains, which was called [[Maxwell Montes]].<ref name=Campbell_et_al_1976/> These three features are now the only ones on Venus that do not have female names.<ref name="jpl-magellan"/>

[[File:Foto de Venera 9.png|thumb|First view and first clear 180-degree panorama of Venus's surface as well as any other planet than Earth (1975, Soviet ''[[Venera&nbsp;9]]'' lander). Black-and-white image of barren, black, slate-like rocks against a flat sky. The ground and the probe are the focus.|upright=2]]

In 1975, the Soviet ''[[Venera 9]]'' and ''[[Venera 10|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]], consisting of two separate missions:<ref name=Colin_Hall_1977/> the [[Pioneer Venus Multiprobe]] and [[Pioneer Venus Orbiter]], orbiting Venus between 1978 and 1992.<ref name=Williams_2005/> In 1982 the first monochrome colour filters images of the surface were obtained with the Soviet ''[[Venera&nbsp;13]]'' and ''[[Venera 14|14]]'' landers. After ''[[Venera 15]]'' and ''[[Venera 16|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 Soviet Venera programme came to a close.<ref name=Greeley_Batson_2007/>

[[File:Russian "Vega" balloon mission to Venus on display at the Udvar-Hazy museum.jpg|thumb|left|upright=0.8|[[Vega programme|Vega balloon probe]] on display at the [[Steven F. Udvar-Hazy Center|Udvar-Hazy Center]] of the [[Smithsonian Institution]]]]

In 1985 the Soviet [[Vega programme]] with its ''[[Vega 1]]'' and ''[[Vega 2]]'' missions carried the last entry probes and carried the first ever extraterrestrial [[aerobot]]s for the first time achieving atmospheric flight outside Earth by employing inflatable balloons.

Between 1990 and 1994, ''[[Magellan (spacecraft)|Magellan]]'' operated in orbit until deorbiting, mapping the surface of Venus. Furthermore, probes like ''[[Galileo (spacecraft)|Galileo]]'' (1990),<ref name="PDS Atmospheres Node 1989">{{cite web | title=Welcome to the Galileo Orbiter Archive Page | website=PDS Atmospheres Node | date=18 October 1989 | url=https://pds-atmospheres.nmsu.edu/data_and_services/atmospheres_data/Galileo/galileo_orbiter.html | access-date=11 April 2023 | archive-date=11 April 2023 | archive-url=https://web.archive.org/web/20230411212904/https://pds-atmospheres.nmsu.edu/data_and_services/atmospheres_data/Galileo/galileo_orbiter.html | url-status=live }}</ref> and ''[[Cassini–Huygens]]'' (1998/1999) visited Venus with flybys en route to other destinations.

===Renewed exploration===
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.<ref name=Howell_2014/> The same and following year ''[[MESSENGER]]'' visited Venus with flybys en route to other destinations.

In 2010, the first successful interplanetary [[solar sail]] spacecraft [[IKAROS]] travelled to Venus for a flyby.

Between 2015 and 2024 Japan's ''[[Akatsuki (spacecraft)|Akatsuki]]'' probe was active in orbit around Venus and [[BepiColombo]] performed flybys in 2020/2021.

[[File:Wispr 4thflyby.gif|thumb|[[WISPR]] of the [[Parker Solar Probe]] took this visible light footage of the nightside in 2021, 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.<ref>{{cite web |last1=Hatfield |first1=Miles |title=Parker Solar Probe Captures Visible Light Images of Venus' Surface |url=https://www.nasa.gov/feature/goddard/2022/sun/parker-solar-probe-captures-its-first-images-of-venus-surface-in-visible-light-confirmed |website=NASA |access-date=29 April 2022 |date=9 February 2022 |archive-date=14 April 2022 |archive-url=https://web.archive.org/web/20220414155959/https://www.nasa.gov/feature/goddard/2022/sun/parker-solar-probe-captures-its-first-images-of-venus-surface-in-visible-light-confirmed/ |url-status=live }}</ref><ref name="Geophysical Research Letters 2022">{{cite journal | journal=Geophysical Research Letters | last1=Wood | first1=B. E. | last2=Hess | first2=P. | last3=Lustig-Yaeger | first3=J. | last4=Gallagher | first4=B. | last5=Korwan | first5=D. | last6=Rich | first6=N. | last7=Stenborg | first7=G. | last8=Thernisien | first8=A. | last9=Qadri | first9=S. N. | last10=Santiago | first10=F. | last11=Peralta | first11=J. | last12=Arney | first12=G. N. | last13=Izenberg | first13=N. R. | last14=Vourlidas | first14=A. | last15=Linton | first15=M. G. | last16=Howard | first16=R. A. | last17= Raouafi | first17=N. E. | doi=10.1029/2021GL096302 | date=9 February 2022 | title=Parker Solar Probe Imaging of the Night Side of Venus | volume=49 | issue=3| article-number=e2021GL096302 | pmid=35864851 | pmc=9286398 | bibcode=2022GeoRL..4996302W }}</ref>]]

===Active and planned missions===
{{Further|List of missions to Venus#Future missions}}
[[File:VenusLanderTopo.jpg|thumb|upright=1.5|Global topographic map of Venus, with all probe landing sites marked (red: images returned; black dot: samples taken and on-site analysed)]]

{{As of|2025}} there are no active probes at Venus, with [[Parker Solar Probe]] scheduled to return repeatedly to Venus until 2030.

Several probes are under development as well as multiple proposed missions still in their early conceptual stages. The next Venus mission scheduled is the [[Venus Life Finder]], expected to launch not earlier than summer 2026.

Indian ISRO is working on [[Venus Orbiter Mission]], aiming to launch it in 2028. UAE mission to asteroids, [[MBR Explorer]], will perform a flyby of the planet. NASA approved two missions to the planet, [[VERITAS (spacecraft)|VERITAS]] and [[DAVINCI]], planned to be launched not earlier then 2031. ESA plans to launch [[EnVision]] also in 2031.

====Objectives====
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.<ref name="O'Rourke Wilson Borrelli Byrne 2023 p.">{{cite journal | last1=O'Rourke | first1=Joseph G. | last2=Wilson | first2=Colin F. | last3=Borrelli | first3=Madison E. | last4=Byrne | first4=Paul K. | last5=Dumoulin | first5=Caroline | last6=Ghail | first6=Richard | last7=Gülcher | first7=Anna J. P. | last8=Jacobson | first8=Seth A. | last9=Korablev | first9=Oleg | last10=Spohn | first10=Tilman | last11=Way | first11=M. J. | last12=Weller | first12=Matt | last13=Westall | first13=Frances | title=Venus, the Planet: Introduction to the Evolution of Earth's Sister Planet | journal=Space Science Reviews | publisher=Springer Science and Business Media LLC | volume=219 | issue=1 | year=2023 | issn=0038-6308 | doi=10.1007/s11214-023-00956-0 | page=10| bibcode=2023SSRv..219...10O | s2cid=256599851 | hdl=20.500.11850/598198 | hdl-access=free }}</ref>

=== Crewed mission concepts ===
Venus has been considered since the 1960s as a waypoint for [[crewed missions to Mars]] through [[Opposition (astronomy)|opposition]] missions instead of direct [[Conjunction (astronomy)|conjunction]] missions with Venus [[gravity assist]] [[flyby (spaceflight)|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.<ref name="Rao 2020">{{cite web | last=Rao | first=Rahul | title=Astronauts bound for Mars should swing by Venus first, scientists say | website=Space.com | date=7 July 2020 | url=https://www.space.com/mars-astronauts-venus-flyby-idea.html | access-date=24 April 2023 | archive-date=24 April 2023 | archive-url=https://web.archive.org/web/20230424055519/https://www.space.com/mars-astronauts-venus-flyby-idea.html | url-status=live }}</ref><ref name="Izenberg McNutt Runyon Byrne 2021 pp. 100–104">{{cite journal | last1=Izenberg | first1=Noam R. | last2=McNutt | first2=Ralph L. | last3=Runyon | first3=Kirby D. | last4=Byrne | first4=Paul K. | last5=MacDonald | first5=Alexander | title=Venus Exploration in the New Human Spaceflight Age | journal=Acta Astronautica | publisher=Elsevier BV | volume=180 | year=2021 | issn=0094-5765 | doi=10.1016/j.actaastro.2020.12.020 | pages=100–104| bibcode=2021AcAau.180..100I | s2cid=219558707 | doi-access=free }}</ref>

==== Possible atmospheric habitation ====
{{See also|Floating cities and islands in fiction#Venus|Colonization of Venus}}
[[File:NASA Cloud City on Venus.jpg|thumb|upright=1.2|Artist's rendering of a NASA [[HAVOC|High Altitude Venus Operational Concept (HAVOC)]] crewed floating outpost on Venus]]

While the surface conditions of Venus are extremely hostile, the atmospheric pressure, temperature, and solar and cosmic radiation 50&nbsp;km above the surface are similar to those at Earth's surface ("clement conditions").<ref name="f997">{{cite journal | last1=Arredondo | first1=Anicia | last2=Hodges | first2=Amorée | last3=Abrahams | first3=Jacob N. H. | last4=Bedford | first4=Candice C. | last5=Boatwright | first5=Benjamin D. | last6=Buz | first6=Jennifer | last7=Cantrall | first7=Clayton | last8=Clark | first8=Joanna | last9=Erwin | first9=Andrew | last10=Krishnamoorthy | first10=Siddharth | last11=Magaña | first11=Lizeth | last12=McCabe | first12=Ryan M. | last13=McIntosh | first13=E. Carrie | last14=Noviello | first14=Jessica L. | last15=Pellegrino | first15=Marielle | last16=Ray | first16=Christine | last17=Styczinski | first17=Marshall J. | last18=Weigel | first18=Peter | title=VALENTInE: A Concept for a New Frontiers–Class Long-duration In Situ Balloon-based Aerobot Mission to Venus | journal=The Planetary Science Journal | volume=3 | issue=7 | date=2022-07-01 | issn=2632-3338 | doi=10.3847/PSJ/ac7324 | doi-access=free | page=152| bibcode=2022PSJ.....3..152A }}</ref><ref name="Herbst Banjac Atri Nordheim 2019 p=A15"/><ref name="Patel Mason Nordheim Dartnell 2022 p=114796"/><ref name="Taylor 2020"/> Among the many engineering challenges for any human presence in the atmosphere of Venus are the corrosive amounts of [[sulfuric acid]] in the atmosphere.<ref name="Landis2003"/> [[Aerostat]]s for crewed exploration and possibly for permanent "[[Floating cities and islands in fiction#Venus|floating cities]]" in the Venusian atmosphere have been proposed as an alternative to the popular idea of living on [[planetary surface]]s such as [[Mars]].<ref name="Landis2003" /><ref name="Архив фантастики"/><ref name="Inner Solar System 2015"/><ref name="Tickle 2015"/><ref name=Warmflash_2017/>  NASA's [[High Altitude Venus Operational Concept]] was a training concept to study a crewed aerostat design.

==Possibility of life==
{{Main|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]] [[microorganism]]s might exist in the cooler, acidic upper layers of the Venusian [[Atmosphere of Venus|atmosphere]].<ref name=Clark_2003/><ref name=Redfern_2004/><ref name="Dartnell2015"/> Such speculations go back to 1967, when [[Carl Sagan]] and [[Harold J. Morowitz]] suggested in a ''[[Nature (journal)|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.<ref name=Sagan_Morowitz_1967/>

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.<ref name="TAJ-20190826"/> Their [[Light absorption|light absorbance]] is almost identical to that of micro-organisms in Earth's clouds. Similar conclusions have been reached by other studies.<ref name="ES-20190903"/>

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.<ref name=Bains_et_al_2021/><ref name=Greaves_et_al_2020/><ref name=Drake_2020/><ref name=Perkins_2020/><ref name=Seager_et_al_2020/> One proposed source for this phosphine is living organisms.<ref name="Sample1"/> The phosphine was detected at heights of at least {{convert|30|mi|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".<ref name=Kooser_2020/><ref name=Bridenstine_2020/>

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.<ref name="Plait1"/> By late October 2020, re-analysis of data with a proper subtraction of background did not show a [[statistically significant]] detection of phosphine.<ref name=Snellen_et_al_2020/><ref name=Thompson2020/><ref name=Cordiner_et_al_2021/>

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 named [[Venus Life Finder]].<ref name="Venus Cloud Life - MIT 2023">{{cite web | title=Rocket Lab Probe | website=Venus Cloud Life – MIT | date=7 March 2023 | url=https://venuscloudlife.com/small-mission/ | access-date=13 May 2023 | archive-date=8 February 2024 | archive-url=https://web.archive.org/web/20240208040505/https://venuscloudlife.com/small-mission/ | url-status=live }}</ref>

===Planetary protection===
Due to the harsh surface environment of Venus, Venus has been under the [[planetary protection]] category two, the second lowest.<ref name=NRC_2006/> This gives it only a remote chance that spacecraft-borne [[interplanetary contamination]] could compromise investigations.

However with findings of potential biosignatures this categorization for at least some atmospheric layers has been called into question, but since these layers have not been identified as sufficiently conductive to live, adjusting the categorization has not been recommended.<ref name="w525">{{cite journal | last1=Zorzano | first1=María Paz | last2=Olsson-Francis | first2=Karen | last3=Doran | first3=Peter T. | last4=Rettberg | first4=Petra | last5=Coustenis | first5=Athena | last6=Ilyin | first6=Vyacheslav | last7=Raulin | first7=Francois | last8=Shehhi | first8=Omar Al | last9=Groen | first9=Frank | last10=Grasset | first10=Olivier | last11=Nakamura | first11=Akiko | last12=Ballesteros | first12=Olga Prieto | last13=Sinibaldi | first13=Silvio | last14=Suzuki | first14=Yohey | last15=Kumar | first15=Praveen | last16=Kminek | first16=Gerhard | last17=Hedman | first17=Niklas | last18=Fujimoto | first18=Masaki | last19=Zaitsev | first19=Maxim | last20=Hayes | first20=Alex | last21=Peng | first21=Jing | last22=Ammannito | first22=Eleonora | last23=Mustin | first23=Christian | last24=Xu | first24=Kanyan | title=The COSPAR planetary protection requirements for space missions to Venus | journal=Life Sciences in Space Research | volume=37 | date=2023 | doi=10.1016/j.lssr.2023.02.001 | doi-access=free | pages=18–24}}</ref>

===Habitability for humans===
While the surface of Venus is very inhospitable to humans, conditions at altitudes of 50 km above the surface have been identified to be not only hospitable for indigenous but also for human life, more so than anywhere else in the Solar System other than Earth. Conditions, from atmospheric pressure, gravity, and temperature to radiation, but except chemical, are all very much like conditions on Earth at surface level. Because of this prospect, floating habitats for humans at such altitudes have been suggested for humans going to Venus.<ref name="e387">{{cite conference | last=Landis | first=Geoffrey A. | title=Settling Venus: A City in the Clouds? | publisher=American Institute of Aeronautics and Astronautics | date=November 16, 2020 | isbn=978-1-62410-608-8 | doi=10.2514/6.2020-4152 | url=https://arc.aiaa.org/doi/10.2514/6.2020-4152 | access-date=September 11, 2025 | page=| url-access=subscription }}</ref>

==In culture==
{{Main|Venus in culture}}
Venus is among the most prominent features in the night sky, and has been treated as particularly important in [[Venus (mythology)|mythology]], [[Planets in astrology#Venus|astrology]] and [[Venus in fiction|fiction]] across many different cultures.

[[File:Kudurru Melishipak Louvre Sb23 n02.jpg|thumb|upright=1.2|The [[Octagram|eight-pointed star]] is a symbol used in some cultures to represent Venus, sometimes combined into a [[star and crescent]] arrangement. Here, the eight pointed star is the [[Star of Ishtar]], the [[Babylonia]]n Venus goddess, alongside the [[solar symbol|solar disk]] of her brother [[Shamash]] and the [[crescent|crescent moon]] of their father [[Sin (mythology)|Sin]] on a [[kudurru|boundary stone]] of [[Meli-Shipak II]], dating to the 12th century&nbsp;BC.]]

{{anchor|Inanna and Shukaletuda}}
Several hymns praise [[Inanna]] in her role as the goddess of the planet Venus.<ref name=Cooley/><ref name="Green1992"/><ref name="Nemet-Nejat"/> 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.<ref name=Cooley/> The discontinuous movements of Venus relate to both mythology as well as Inanna's dual nature.<ref name=Cooley/> 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.<ref name=Cooley/> 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.<ref name=Cooley/> In ''[[Inanna and Shukaletuda]]'' and ''[[Inanna's Descent into the Underworld]]'' appear to parallel the motion of the planet Venus.<ref name=Cooley/> In ''Inanna and Shukaletuda'', Shukaletuda is described as scanning the heavens in search of Inanna, possibly searching the eastern and western horizons.<ref name="Cooley2"/> In the same myth, while searching for her attacker, Inanna herself makes several movements that correspond with the movements of Venus in the sky.<ref name=Cooley/>

Via [[Mesopotamia]]n influence, it is possible that the [[Ancient Egypt]]ians and [[ancient Greeks|Greeks]] knew that the morning star and the evening star were one and the same as early as the second millennium&nbsp;BC—or the [[Late Period of ancient Egypt|Late Period]] at the latest.<ref name="Parker 1974"/><ref name="Quack 2019"/> The Egyptians knew the morning star as {{tlit|egy|Tioumoutiri}} and the evening star as {{tlit|egy|Ouaiti}}.<ref name=Cattermole_Moore_1997/> They depicted Venus at first as a [[Phoenix (mythology)|phoenix]] or [[heron]] (see [[Bennu]]),<ref name="Parker 1974"/> calling it 'the crosser' or 'star with crosses',<ref name="Parker 1974"/> associating it with [[Osiris]], and later depicting it as two-headed (with human or falcon heads), and associated it with [[Horus]],<ref name="Quack 2019"/> son of [[Isis]] (which during the even later [[Hellenistic period]] was together with [[Hathor]] identified with [[Aphrodite]]). The Greeks used the names {{tlit|grc|[[Phōsphoros]]}}, meaning 'light-bringer' (whence the element [[phosphorus]]; alternately {{tlit|grc|Ēōsphoros}}, meaning 'dawn-bringer'), for the morning star, and {{tlit|grc|[[Hesperos]]}}, meaning 'Western one', for the evening star,<ref name="EBLCM"/> 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 (mythology)|Venus]]", the traditional two Greek names continued to be used, though usually translated to Latin as {{lang|la|[[Lucifer]]}} and {{lang|la|[[Hesperus|Vesper]]}}.<ref name="EBLCM"/><ref name=Cicero/>

Classical poets such as [[Homer]], [[Sappho]], [[Ovid]] and [[Virgil]] spoke of the star and its light.<ref name=Atsma/> Poets such as [[William Blake]], [[Robert Frost]], [[Letitia Elizabeth Landon]], [[Alfred Lord Tennyson]] and [[William Wordsworth]] wrote odes to it.<ref name=Sobel_2005/> The composer [[Gustav Holst|Holst]] included it as [[The Planets#Venus|the second movement]] of his ''[[The Planets]]'' suite.

In India, the name for Venus in Sanskrit was {{tlit|sa|Shukra Graha}}, meaning 'the planet Shukra'—in reference to [[Shukra]], a powerful saint. As appears in [[Vedic astrology]],<ref name="bhalla06"/> the Sanskrit name ''Shukra'' means 'clear, pure' or 'brightness, clearness'. 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.<ref name="behari_frawley03"/>

The English name ''Venus'' stems originally from the [[Roman religion|ancient Roman]]s. Romans named Venus after [[Venus (goddess)|their goddess of love]], who in turn was based on the [[Ancient Greek religion|ancient Greek]] love goddess [[Aphrodite]],<ref name="Getty"/> 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.<ref name="Nemet-Nejat"/><ref name="Green1992"/> The [[Planetary hours|weekday of the planet]] and these goddesses is [[Friday]], named after the Germanic goddess [[Frigg]], who has been associated with the Roman goddess Venus.

In Chinese, the planet is called ''metal star'' or ''gold star'' ({{zhi|c=金星|p=Jīnxīng}}); of the [[Five elements (Chinese philosophy)|five elements]] of traditional Chinese philosophy, Venus was historically associated with [[Metal (wuxing)|metal]]. These traditions are shared among modern [[Chinese culture|Chinese]], [[Japanese culture|Japanese]], [[Korean culture|Korean]] and [[Culture of Vietnam|Vietnamese]] cultures, including a name for the planet literally meaning 'metal star' ({{lang|zh|金星}}) in each language.<ref name=De_Groot_1912/><ref name=Crump_1992/><ref name=Hulbert_1909/><ref name=VOER/>

The [[Maya civilisation|Maya]] considered Venus to be the most important celestial body after the Sun and Moon. They called it {{tlit|myn|Chac ek}},<ref name="Volume 7 of Mayan studies"/> or {{tlit|myn|Noh Ek'}}, 'the Great Star'.<ref name="Milbrath"/> The cycles of Venus were important to their calendar and were described in some of their books, such as the ''[[Maya Codex of Mexico]]'' and ''[[Dresden Codex]]''. The [[flag of Chile]] ({{lang|es|Estrella Solitaria}}, 'Lone Star') depicts Venus.

===Modern culture===
{{See also|Venus in fiction}}
[[File:Van Gogh - Starry Night - Google Art Project.jpg|thumb|Venus is portrayed just to the right of the large cypress tree in [[Vincent van Gogh]]'s 1889 painting ''[[The Starry Night]]''.<ref name=Whitney_1986/><ref name=Boime_1984/>]]

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 [[Planetary habitability|habitable]] by humans.<ref name="miller"/> 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.<ref name=Dick_2001/> As scientific knowledge of Venus advanced, science fiction authors tried to keep pace, particularly by conjecturing human attempts to [[Terraforming of Venus|terraform Venus]].<ref name=Seed_2005/>

=== Symbols ===
{{Main|Venus symbol}}
[[file:Venus symbol (planetary color).svg|frameless|left|80px]]

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,<ref name="Schott 2005 pp. 1509–1510"/><ref name="stearn1961"/><ref name="stearn"/> 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 [[heteronormative]]ly, 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]]''.<ref name="Brammer 2020"/>

The Venus symbol was also used in Western [[alchemy]] representing the element [[copper]] (like the symbol of [[Mercury (planet)|Mercury]] is also the symbol of the [[element mercury]]),<ref name="stearn1961" /><ref name="stearn" /> 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.<ref name="stearn1961" /><ref name="stearn" />

Besides the Venus symbol, many other symbols have been associated with Venus, other common ones are the [[star and crescent|crescent or particularly the star]], as with the [[Star of Ishtar]].<ref>{{Cite book |last=Liungman |first=Carl G. |url=https://books.google.com/books?id=06ALKxX225IC |title=Symbols: Encyclopedia of Western Signs and Ideograms |date=2004 |publisher=HME Publishing |isbn=978-91-972705-0-2 |page=228 |language=en}}</ref>

== See also ==
{{Portal|Solar System|Outer space|Astronomy}}
* [[Outline of Venus]]
* [[List of gravitationally rounded objects of the Solar System#Planets|Physical properties of planets in the Solar System]]
* [[Venus zone]]

== Notes ==

{{Reflist|group=note}}

== References ==

{{Reflist|refs=

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<ref name=Margot_et_al_2021>{{cite journal
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<ref name="American Chemical Society 2013">{{cite web
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<ref name="horizons">{{cite web
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| archive-url=https://web.archive.org/web/20230818120948/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%272%27&TABLE_TYPE=%27ELEMENTS%27&START_TIME=%272000-01-01%27&STOP_TIME=%272000-01-02%27&STEP_SIZE=%27200%20years%27&CENTER=%27%40Sun%27&OUT_UNITS=%27AU-D%27
 | url-status=live
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<ref name=Lexico_Venusian>{{Cite encyclopedia
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<ref name="MoreOrLess">{{cite web
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<ref name="Solex11">{{cite web
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<ref name=Atsma>{{cite web
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<ref name=Clark_2003>{{cite news
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<ref name="TAJ-20190826">{{cite journal
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<ref name="ES-20190903">{{cite news
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<ref name="stearn">{{cite journal
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<ref name=Bains_et_al_2021>{{cite journal
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 | journal=Astrobiology | year=2021
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 | bibcode=2021AsBio..21.1277B|s2cid=221655331}}</ref>

<ref name=Perkins_2020>{{cite news
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<ref name=Seager_et_al_2020>{{cite journal
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 | arxiv=2009.06474 | s2cid=221127006 }}</ref>

<ref name="Sample1">{{cite news
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 | url-status=live }}</ref>

<ref name=Kooser_2020>{{cite news
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 | agency=CNet | date=14 September 2020
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<ref name=Bridenstine_2020>{{cite tweet
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 | number=1305598182571810822
 | date=14 September 2020
| title=Life on Venus? }}</ref>

<ref name="Plait1">{{cite web
 | title=Update: Life Above Hell? Serious doubt cast on Venus phosphine finding
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| website=Syfy.com | publisher=[[Syfy]]
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<ref name=Snellen_et_al_2020>{{cite journal
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<ref name=Thompson2020>{{cite journal
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<ref name=Cordiner_et_al_2021>{{cite journal
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<ref name=NRC_2006>{{cite book
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<!--  <ref name=Frazier_2021>{{cite web
 | title=Parker Solar Probe Primed for Fourth Venus Flyby
 | last=Frazier | first=Sarah
 | website=NASA | date=19 February 2021
| url=https://blogs.nasa.gov/parkersolarprobe/2021/02/19/parker-solar-probe-primed-for-fourth-venus-flyby/
 | access-date=22 April 2021 | archive-date=22 April 2021
| archive-url=https://web.archive.org/web/20210422095750/https://blogs.nasa.gov/parkersolarprobe/2021/02/19/parker-solar-probe-primed-for-fourth-venus-flyby/
 | url-status=live}}</ref>-->

<ref name="Архив фантастики">{{cite web
 | title=Архив фантастики
 | website=Архив фантастики | language=ru
 | url=http://archivsf.narod.ru/1929/sergey_zhitomirsky/index.htm
 | access-date=2 September 2021 | archive-date=2 September 2021
| archive-url=https://web.archive.org/web/20210902230735/http://archivsf.narod.ru/1929/sergey_zhitomirsky/index.htm
 | url-status=live }}</ref>

<ref name="Inner Solar System 2015">{{cite book
 | title=Inner Solar System
 | editor-last=Badescu | editor-first=Viorel
 | editor-last2=Zacny | editor-first2=Kris
 | publisher=Springer International Publishing
 | year=2015 | isbn=978-3-319-19568-1
 | doi=10.1007/978-3-319-19569-8 }}</ref>

<ref name="Tickle 2015">{{cite web
 | title=A Look Into Whether Humans Should Try to Colonize Venus Instead of Mars
 | last=Tickle | first=Glen
 | website=Laughing Squid | date=5 March 2015
 | url=https://laughingsquid.com/a-look-into-whether-humans-should-try-to-colonise-venus-instead-of-mars/
 | access-date=1 September 2021 | archive-date=1 September 2021
| archive-url=https://web.archive.org/web/20210901191020/https://laughingsquid.com/a-look-into-whether-humans-should-try-to-colonise-venus-instead-of-mars/
 | url-status=live }}</ref>

<ref name=Warmflash_2017>{{cite web
 | title=Colonization of the Venusian Clouds: Is 'Surfacism' Clouding Our Judgement?
 | first=David | last=Warmflash
 | website=Vision Learning | date=14 March 2017
| url=https://www.visionlearning.com/blog/2017/03/14/colonization-venusian-clouds-surfacism-clouding-judgement/
 | access-date=20 September 2019 | archive-date=11 December 2019
| archive-url=https://web.archive.org/web/20191211122431/https://www.visionlearning.com/blog/2017/03/14/colonization-venusian-clouds-surfacism-clouding-judgement/
 | url-status=live }}</ref>

<ref name="Landis2003">{{cite conference
 | first=Geoffrey A. | last=Landis
 | book-title=AIP Conference Proceedings
 | title=Colonization of Venus
 | volume=654 | issue=1 | pages=1193–1198
 | doi=10.1063/1.1541418 | date=2003
 | url=http://link.aip.org/link/?APCPCS/654/1193/1
 | archive-url=https://archive.today/20120711103532/http://link.aip.org/link/?APCPCS/654/1193/1
 | archive-date=11 July 2012 | url-access=subscription
 }}</ref>
 
<ref name=Lawrence_2005>{{cite web
 | title=In Search of the Venusian Shadow
 | last=Lawrence | first=Pete | date=2005
 | website=Digitalsky.org.uk | access-date=13 June 2012
| url=http://www.digitalsky.org.uk/venus/shadow-of-venus.html
 | archive-url=https://web.archive.org/web/20120611003523/http://www.digitalsky.org.uk/venus/shadow-of-venus.html
 | archive-date=11 June 2012 }}</ref>

<ref name=Walker_2017>{{cite web
 | title=Viewing Venus in Broad Daylight
 | first=John | last=Walker
 | work=Fourmilab Switzerland
 | access-date=19 April 2017 | archive-date=29 March 2017
| url=http://www.fourmilab.ch/images/venus_daytime/
 | archive-url=https://web.archive.org/web/20170329024632/https://www.fourmilab.ch/images/venus_daytime/
 | url-status=live }}</ref>

<ref name="Jakosky">{{cite book
 | title=The New Solar System
 | last=Jakosky |first=Bruce M.
 | chapter=Atmospheres of the Terrestrial Planets
 | editor1-last=Beatty | editor1-first=J. Kelly
 | editor2-last=Petersen | editor2-first=Carolyn Collins
 | editor3-last=Chaikin | editor3-first=Andrew
 | edition=4th | date=1999 | pages=175–200
 | location=Boston |publisher=Sky Publishing
 | isbn=978-0-933346-86-4 |oclc=39464951}}</ref>

<ref name=Shiga_2007>{{cite web
 | title=Did Venus's ancient oceans incubate life?
 | first=David | last=Shiga
 | work=New Scientist | date=10 October 2007
| url=https://www.newscientist.com/article/dn12769-did-venuss-ancient-oceans-incubate-life.html
 | access-date=17 September 2017 |archive-date=24 March 2009
| archive-url=https://web.archive.org/web/20090324134332/https://www.newscientist.com/article/dn12769-did-venuss-ancient-oceans-incubate-life.html
 | url-status=live }}</ref>

<ref name="Brammer 2020">{{cite web
 | last=Brammer
 | first=John Paul
 | title=Love/Hate Reads: 'Men Are From Mars, Women Are From Venus,' Revisited
 | website=VICE
 | date=10 February 2020
 | url=https://www.vice.com/en/article/lovehate-reads-men-are-from-mars-women-are-from-venus-revisited/
 | access-date=17 April 2023
 | archive-date=17 April 2023
| archive-url=https://web.archive.org/web/20230417234135/https://www.vice.com/en/article/n7j3nm/lovehate-reads-men-are-from-mars-women-are-from-venus-revisited
 | url-status=live
 }}</ref>

<ref name="Schott 2005 pp. 1509–1510">{{cite journal
 | title=Sex symbols ancient and modern: their origins and iconography on the pedigree
 | last=Schott | first=G. D.
 | journal=BMJ | date=22 December 2005
 | volume=331 | issue=7531 | pages=1509–1510
 | issn=0959-8138 | doi=10.1136/bmj.331.7531.1509
 | pmid=16373733 | pmc=1322246 }}</ref>

<ref name="Parker 1974">{{cite journal
 | title=Ancient Egyptian Astronomy
 | last=Parker | first=R. A.
 | journal=Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
 | publisher=The Royal Society | year=1974
 | volume=276 | issue=1257 | pages=51–65
 | issn=0080-4614 | jstor=74274 | doi=10.1098/rsta.1974.0009
 | bibcode=1974RSPTA.276...51P | s2cid=120565237 }}</ref>

<ref name="Quack 2019">{{cite book 
 | title=Oxford Research Encyclopedia of Planetary Science
 | last=Quack | first=Joachim Friedrich
 | chapter=The Planets in Ancient Egypt
 | publisher=Oxford University Press | date=23 May 2019
 | doi=10.1093/acrefore/9780190647926.013.61 | isbn=978-0-19-064792-6 }}</ref>

<ref name="Getty">{{cite web
 | title=Aphrodite and the Gods of Love: Roman Venus (Getty Villa Exhibitions)
 | website=Getty
 | url=https://www.getty.edu/art/exhibitions/aphrodite/venus.html
 | access-date=15 April 2023
 | archive-date=12 April 2023
| archive-url=https://web.archive.org/web/20230412080715/https://www.getty.edu/art/exhibitions/aphrodite/venus.html
 | url-status=live
 }}</ref>

<ref name=Whitney_1986>{{cite journal
 | title=The Skies of Vincent van Gogh
 | last=Whitney | first=Charles A.
 | journal=Art History|date=September 1986
 | volume=9| issue=3 | page=356
 | doi=10.1111/j.1467-8365.1986.tb00206.x }}</ref>

<ref name=Boime_1984>{{cite journal
 | last=Boime | first=Albert | author-link=Albert Boime
 | title=Van Gogh's ''Starry Night'': A History of Matter and a Matter of History
 | journal=Arts Magazine | date=December 1984 | page=88
 | url=http://www.albertboime.com/Articles/Dec1984.pdf
 | access-date=28 July 2018 | archive-date=23 November 2018
| archive-url=https://web.archive.org/web/20181123150057/http://www.albertboime.com/Articles/Dec1984.pdf
 | url-status=live }}</ref>

<ref name="u3r1a">{{cite journal | title=The deep atmosphere of Venus and the possible role of density-driven separation of CO2 and N2 | last1=Lebonnois | first1=Sebastien | last2=Schubert | first2=Gerald | journal=Nature Geoscience | publisher=Springer Science and Business Media LLC | volume=10 | issue=7 | date=26 June 2017 | pages=473–477 | issn=1752-0894 | doi=10.1038/ngeo2971 | bibcode=2017NatGe..10..473L | s2cid=133864520 | url=https://hal.archives-ouvertes.fr/hal-01635402/file/deepatm_persp_rev2.pdf | access-date=11 August 2023 | archive-date=4 May 2019 | archive-url=https://web.archive.org/web/20190504081028/https://hal.archives-ouvertes.fr/hal-01635402/file/deepatm_persp_rev2.pdf | url-status=live }}</ref>

<ref name="Ernst 2022">{{cite web
 | title=Venus was once more Earth-like, but climate change made it uninhabitable
 | last=Ernst
 | first=Richard
 | website=The Conversation
 | date=3 November 2022
 | url=http://theconversation.com/venus-was-once-more-earth-like-but-climate-change-made-it-uninhabitable-150445
 | access-date=21 April 2023
 | archive-date=21 April 2023
| archive-url=https://web.archive.org/web/20230421033219/http://theconversation.com/venus-was-once-more-earth-like-but-climate-change-made-it-uninhabitable-150445
 | url-status=live
 }}</ref>

<ref name="Way Del Genio 2020 p.">{{cite journal
 | title=Venusian Habitable Climate Scenarios: Modeling Venus Through Time and Applications to Slowly Rotating Venus-Like Exoplanets
 | last1=Way | first1=M. J. | last2=Del Genio | first2=Anthony D.
 | journal=Journal of Geophysical Research: Planets
 | publisher=American Geophysical Union (AGU)
 | volume=125 | issue=5 | year=2020
 | article-number=e2019JE006276 | issn=2169-9097 | doi=10.1029/2019je006276
 | arxiv=2003.05704 | bibcode=2020JGRE..12506276W }}</ref>

<ref name="Way Del Genio Kiang Sohl 2016 pp. 8376–8383">{{cite journal
 | title=Was Venus the first habitable world of our solar system?
 | last1=Way | first1=M. J. | last2=Del Genio | first2=Anthony D.
 | last3=Kiang | first3=Nancy Y. | last4=Sohl | first4=Linda E.
 | last5=Grinspoon | first5=David H. | last6=Aleinov | first6=Igor
 | last7=Kelley | first7=Maxwell | last8=Clune | first8=Thomas
 | journal=Geophysical Research Letters
 | publisher=American Geophysical Union (AGU)
 | volume=43 | issue=16 | date=28 August 2016 | pages=8376–8383
 | issn=0094-8276 | doi=10.1002/2016gl069790 | pmid=28408771
 | pmc=5385710 | arxiv=1608.00706 | bibcode=2016GeoRL..43.8376W }}</ref>

<ref name="Steigerwald 2022">{{cite web
 | title=NASA Study: Massive Volcanism May Have Altered Ancient Venus' Climate
 | last=Steigerwald
 | first=Bill
 | website=NASA
 | date=2 November 2022
 | url=http://www.nasa.gov/feature/goddard/2022/venus-volcanic-climate-change
 | access-date=5 May 2023
 | archive-date=10 May 2023
| archive-url=https://web.archive.org/web/20230510213318/https://www.nasa.gov/feature/goddard/2022/venus-volcanic-climate-change/
 | url-status=live
 }}</ref>

<ref name="Tillman 2018">{{cite web
 | title=Venus' Atmosphere: Composition, Climate and Weather
 | last=Tillman
 | first=Nola Taylor
 | website=Space.com
 | date=18 October 2018
 | url=https://www.space.com/18527-venus-atmosphere.html
 | access-date=9 May 2023
 | archive-date=9 May 2023
| archive-url=https://web.archive.org/web/20230509122404/https://www.space.com/18527-venus-atmosphere.html
 | url-status=live
 }}</ref>

<ref name="Davis 2021">{{cite web
 | title=Why Is Venus So Bright? Here's How Its Proximity to Earth, Highly Reflected Clouds Affects It
 | last=Davis
 | first=Margaret
 | website=Science Times
 | date=14 July 2021
 | url=https://www.sciencetimes.com/articles/32272/20210714/why-venus-bright-heres-proximity-earth-highly-reflected-clouds-affects.htm
 | access-date=11 June 2023
 | archive-date=13 December 2022
| archive-url=https://web.archive.org/web/20221213203043/https://www.sciencetimes.com/articles/32272/20210714/why-venus-bright-heres-proximity-earth-highly-reflected-clouds-affects.htm
 | url-status=live
 }}</ref>

<ref name="ESA Blog Navigator – Navigator page for active ESA blogs 2012">{{cite web
 | title=Venus and Earth: worlds apart – Transit of Venus blog
 | website=ESA Blog Navigator – Navigator page for active ESA blogs
 | date=31 May 2012
 | url=https://blogs.esa.int/venustransit/2012/05/31/venus-and-earth-worlds-apart/
 | access-date=11 June 2023
 | archive-date=11 June 2023
| archive-url=https://web.archive.org/web/20230611201608/https://blogs.esa.int/venustransit/2012/05/31/venus-and-earth-worlds-apart/
 | url-status=live
 }}</ref>

<ref name=sci_news_1976>{{cite journal
 | title=The Unveiling of Venus: Hot and Stifling
 | journal=Science News | date=19 June 1976 
 | volume=109 | issue=25 | pages=388–389
 | jstor=3960800 | doi=10.2307/3960800
 | quote=100 watts per square meter ... 14,000 lux ... corresponds to ... daytime with overcast clouds }}</ref>

}}

== Further reading ==
* {{cite journal |last1=O'Rourke |first1=Joseph G. |last2=Wilson |first2=Colin F. |last3=Borrelli |first3=Madison E. |last4=Byrne |first4=Paul K. |last5=Dumoulin |first5=Caroline |last6=Ghail |first6=Richard |last7=Gülcher |first7=Anna J. P. |last8=Jacobson |first8=Seth A. |last9=Korablev |first9=Oleg |last10=Spohn |first10=Tilman |last11=Way |first11=M. J. |last12=Weller |first12=Matt |last13=Westall |first13=Frances |title=Venus, the Planet: Introduction to the Evolution of Earth's Sister Planet |journal=Space Science Reviews |date=6 February 2023 |volume=219 |issue=1 |page=10 |doi=10.1007/s11214-023-00956-0 |bibcode=2023SSRv..219...10O |url=https://link.springer.com/article/10.1007/s11214-023-00956-0 |access-date=6 February 2025 |language=en |issn=1572-9672|hdl=20.500.11850/598198 |hdl-access=free }}
* {{cite journal |last1=Widemann |first1=Thomas |last2=Smrekar |first2=Suzanne E. |last3=Garvin |first3=James B. |last4=Straume-Lindner |first4=Anne Grete |last5=Ocampo |first5=Adriana C. |last6=Schulte |first6=Mitchell D. |last7=Voirin |first7=Thomas |last8=Hensley |first8=Scott |last9=Dyar |first9=M. Darby |last10=Whitten |first10=Jennifer L. |last11=Nunes |first11=Daniel C. |last12=Getty |first12=Stephanie A. |last13=Arney |first13=Giada N. |last14=Johnson |first14=Natasha M. |last15=Kohler |first15=Erika |last16=Spohn |first16=Tilman |last17=O'Rourke |first17=Joseph G. |last18=Wilson |first18=Colin F. |last19=Way |first19=Michael J. |last20=Ostberg |first20=Colby |last21=Westall |first21=Frances |last22=Höning |first22=Dennis |last23=Jacobson |first23=Seth |last24=Salvador |first24=Arnaud |last25=Avice |first25=Guillaume |last26=Breuer |first26=Doris |last27=Carter |first27=Lynn |last28=Gilmore |first28=Martha S. |last29=Ghail |first29=Richard |last30=Helbert |first30=Jörn |last31=Byrne |first31=Paul |last32=Santos |first32=Alison R. |last33=Herrick |first33=Robert R. |last34=Izenberg |first34=Noam |last35=Marcq |first35=Emmanuel |last36=Rolf |first36=Tobias |last37=Weller |first37=Matt |last38=Gillmann |first38=Cedric |last39=Korablev |first39=Oleg |last40=Zelenyi |first40=Lev |last41=Zasova |first41=Ludmila |last42=Gorinov |first42=Dmitry |last43=Seth |first43=Gaurav |last44=Rao |first44=C. V. Narasimha |last45=Desai |first45=Nilesh |title=Venus Evolution Through Time: Key Science Questions, Selected Mission Concepts and Future Investigations |journal=Space Science Reviews |date=October 2023 |volume=219 |issue=7 |page=56 |doi=10.1007/s11214-023-00992-w |bibcode=2023SSRv..219...56W |display-authors=1|hdl=10852/109541 |hdl-access=free }}

== External links ==
{{Sister project links|commonscat=Venus (planet)}}
* [https://web.archive.org/web/20150906034051/http://solarsystem.nasa.gov/planets/venus Venus profile] at NASA's Solar System Exploration site
* [http://nssdc.gsfc.nasa.gov/planetary/planets/venuspage.html Missions to Venus] {{Webarchive|url=https://web.archive.org/web/20150210163349/http://nssdc.gsfc.nasa.gov/planetary/planets/venuspage.html |date=10 February 2015 }} and [http://nssdc.gsfc.nasa.gov/imgcat/thumbnail_pages/venus_thumbnails.html Image catalogue] {{Webarchive|url=https://web.archive.org/web/20150329025335/http://nssdc.gsfc.nasa.gov/imgcat/thumbnail_pages/venus_thumbnails.html |date=29 March 2015 }} at the [[National Space Science Data Center]]
* [http://www.mentallandscape.com/V_Venus.htm Soviet Exploration of Venus] and [http://www.mentallandscape.com/C_CatalogVenus.htm Image catalogue] at Mentallandscape.com
* [https://web.archive.org/web/20151015045714/http://www.strykfoto.org/venera.htm Image catalogue from the Venera missions]
* [http://www.nineplanets.org/venus.html Venus page] at ''[[The Nine Planets]]''
* [http://eclipse.gsfc.nasa.gov/transit/catalogue/VenusCatalog.html Transits of Venus] {{Webarchive|url=https://web.archive.org/web/20120319134106/http://eclipse.gsfc.nasa.gov/transit/catalogue/VenusCatalog.html |date=19 March 2012 }} at NASA.gov
* [http://www.geody.com/?world=venus Geody Venus], a search engine for surface features
* [https://gravitysimulator.org/solar-system/pentagram-of-venus Interactive 3D gravity simulation of the pentagram that the orbit of Venus traces when Earth is held fixed at the centre of the coordinate system]

=== Cartographic resources ===
* [https://web.archive.org/web/20071005184007/http://www.mapaplanet.org/explorer/venus.html Map-a-Planet: Venus] by the [[U.S. Geological Survey]]
* [https://web.archive.org/web/20160112001040/http://planetarynames.wr.usgs.gov/Page/VENUS/target Gazetteer of Planetary Nomenclature: Venus] by the [[International Astronomical Union]]
* [http://www.lpi.usra.edu/resources/vc/vchome.shtml Venus crater database] by the [[Lunar and Planetary Institute]]
* [http://planetologia.elte.hu/venusz-terkep-elte-ttk-kavucs.pdf Map of Venus] by [[Eötvös Loránd University]]
* [https://www.google.com/maps/space/venus/@33.5623476,-46.1493481,7057278m/data=!3m1!1e3 Google Venus 3D], interactive map of the planet

{{Venus}}
{{Solar System}}
{{Venus spacecraft}}
{{Authority control}}
{{Portal bar|Stars|Spaceflight|Outer space}}

[[Category:Venus| ]]
[[Category:Planets of the Solar System]]
[[Category:Terrestrial planets]]
[[Category:Astronomical objects known since antiquity]]
[[Category:Solar System]]
[[Category:Lucifer]]