Venus

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

Venus
True colour image of Venus, as captured by MESSENGER. A cloud layer permanently obscures the surface.
Designations
Pronunciation/ˈviːnəs/ ⓘ
Named after
Roman goddess of love (see goddess Venus)
AdjectivesVenusian /vɪˈnjuːziən, -ʒən/,[1] rarely Cytherean /sɪθəˈriːən/[2] or Venerean / Venerian /vɪˈnɪəriən/[3]
Symbol
Orbital characteristics[4][5]
Epoch J2000
Aphelion0.728213 AU (108.94 million km)
Perihelion0.718440 AU (107.48 million km)
0.723332 AU (108.21 million km)
Eccentricity0.006772[6]
  • 224.701 d[4]
  • 0.615198 Julian year
  • 0.615187 sidereal year
  • 1.92 Venus solar day
583.92 days[4]
Average orbital speed
35.02 km/s
50.115°
Inclination
76.680°[6]
Argument of perihelion
54.884°
SatellitesNone
Physical characteristics
Mean radius
  • 6,051.8±1.0 km[8]
  • 0.9499 Earths
Flattening0[8]
  • 4.6023×108 km2
  • 0.902 Earths
Volume
  • 9.2843×1011 km3
  • 0.857 Earths
Mass
  • 4.8675×1024 kg[9]
  • 0.815 Earths
Mean density
5.243 g/cm3
Surface gravity
8.87 m/s2 (0.904 g0)
10.36 km/s (6.44 mi/s)[10]
Synodic rotation period
−116.75 d (retrograde)[11]
1 Venus solar day
Sidereal rotation period
−243.0226 d (retrograde)[12]
Equatorial rotation velocity
1.81 m/s
2.64° (for retrograde rotation)
177.36° (to orbit)[4][note 1]
North pole right ascension
North pole declination
67.16°[14]
Albedo
Temperature232 K (−41 °C) (blackbody temperature)[17]
Surface temp. min mean max
Kelvin 737 K[4]
Celsius 464 °C
Fahrenheit 867 °F
Surface absorbed dose rate2.1×10−6 μGy/h[18]
Surface equivalent dose rate2.2×10−6 μSv/h
0.092–22 μSv/h at cloud level[18]
−4.92 to −2.98[19]
−4.4[20]
Angular diameter
9.7″–66.0″[4]
Atmosphere[4]
Surface pressure
93 bar (9.3 MPa)
92 atm
Composition by volume
  1. ^ Defining the rotation as retrograde, as done by NASA space missions and the USGS, puts Ishtar Terra in the northern hemisphere and makes the axial tilt 2.64°. Following the right-hand rule for prograde rotation puts Ishtar Terra in the negative hemisphere and makes the axial tilt 177.36°.

Venus is the second planet from the Sun. It is 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 planets 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 its atmosphere being far thicker and denser than that of any other rocky body in the Solar System. The atmosphere is composed of mostly 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 737 K (464 °C; 867 °F) and a 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, appearing brighter than any other natural point of light in Earth's sky,[21][22] 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 periods of 1.6 years. In the course of this, Venus comes closer to Earth than any other planet, while on average Mercury stays closer to Earth and 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 assists, offering a faster and more economical route. Venus has no moons and a very slow 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 internal dynamo, it is induced by the solar wind interacting with the atmosphere. Internally, Venus has a core, mantle, and crust. Internal heat escapes through active volcanism,[23][24] resulting in resurfacing, instead of plate tectonics. Venus may have had liquid surface water early in its history with a habitable environment,[25][26] before a runaway greenhouse effect evaporated any water and turned Venus into its present state.[27][28][29] 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.

Humans have observed Venus throughout history across the globe, 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. The data from these missions revealed the strong greenhouse effect of carbon dioxide in its atmosphere, which raised concerns about increasing carbon dioxide levels in Earth's atmosphere and their role in driving climate change.[30] 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.

  1. ^ Cite error: The named reference Lexico_Venusian was invoked but never defined (see the help page).
  2. ^ "Cytherean". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  3. ^ "Venerean, Venerian". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  4. ^ a b c d e f g Cite error: The named reference fact was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference horizons was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference VSOP87 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Souami_Souchay_2012 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Seidelmann2007 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Konopliv1999 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference NASA_2015 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference planetary-facts was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Margot_et_al_2021 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference iauwg_ccrsps2000 was invoked but never defined (see the help page).
  14. ^ a b Archinal, B. A.; Acton, C. H.; A'Hearn, M. F.; Conrad, A.; Consolmagno, G. J.; Duxbury, T.; Hestroffer, D.; Hilton, J. L.; Kirk, R. L.; Klioner, S. A.; McCarthy, D.; Meech, K.; Oberst, J.; Ping, J.; Seidelmann, P. K. (2018). "Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015". Celestial Mechanics and Dynamical Astronomy. 130 (3): 22. Bibcode:2018CeMDA.130...22A. doi:10.1007/s10569-017-9805-5. ISSN 0923-2958.
  15. ^ Cite error: The named reference Mallama_et_al was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Haus_et_al was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference American Chemical Society 2013 was invoked but never defined (see the help page).
  18. ^ a b Cite error: The named reference radiation-levels was invoked but never defined (see the help page).
  19. ^ Cite error: The named reference Mallama_and_Hilton was invoked but never defined (see the help page).
  20. ^ "Encyclopedia – the brightest bodies". IMCCE. Archived from the original on 24 July 2023. Retrieved 29 May 2023.
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  23. ^ Andrews, Roy George (27 May 2024). "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". The New York Times. Archived from the original on 28 May 2024. Retrieved 28 May 2024.
  24. ^ Sulcanese, Davide; Mitri, Giuseppe; Mastrogiuseppe, Marco (27 May 2024). "Evidence of ongoing volcanic activity on Venus revealed by Magellan radar". Nature Astronomy. 8 (8): 973–982. Bibcode:2024NatAs...8..973S. doi:10.1038/s41550-024-02272-1. ISSN 2397-3366. Archived from the original on 28 May 2024. Retrieved 28 May 2024.
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  26. ^ Cite error: The named reference NA-20231026 was invoked but never defined (see the help page).
  27. ^ Cite error: The named reference Jakosky was invoked but never defined (see the help page).
  28. ^ Cite error: The named reference Hashimoto_et_al_2008 was invoked but never defined (see the help page).
  29. ^ Cite error: The named reference Shiga_2007 was invoked but never defined (see the help page).
  30. ^ Cite error: The named reference Newitz 2013 was invoked but never defined (see the help page).
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