Venus

planet second-closest to the Sun in the Solar System
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Venus is the second planet from the Sun.[3] Venus is the only planet in the Solar System that has a day longer than a year. The year length of Venus is 225 Earth days. The day length of Venus is 243 Earth days.[3]

Venus ♀
Venus in approximately true colour, a nearly uniform pale cream, although the image has been processed to bring out details.[1] The planet's disc is about three-quarters illuminated; almost no variation or detail can be seen in the clouds
A real-colour image taken by Mariner 10 processed from two filters, the surface is obscured by thick sulfuric acid clouds
Designations
Pronunciation/ˈvnəs/ (audio speaker iconlisten)
AdjectivesVenusian or (rarely) Cytherean, Venerean
Orbital characteristics
Epoch J2000
Aphelion
  • 0.728213 AU
  • 108,939,000 km
Perihelion
  • 0.718440 AU
  • 107,477,000 km
  • 0.723332 AU
  • 108,208,000 km
Eccentricity0.006772
583.92 days
35.02 km/s
50.115°
Inclination
76.680°
54.884°
SatellitesNone
Physical characteristics
Mean radius
  • 6,051.8±1.0 km
  • 0.9499 Earths
Flattening0
  • 4.6023×108 km2
  • 0.902 Earths
Volume
  • 9.2843×1011 km3
  • 0.866 Earths
Mass
  • 4.8675×1024 kg
  • 0.815 Earths
Mean density
5.243 g/cm3
  • 8.87 m/s2
  • 0.904 g
10.36 km/s (6.44 mi/s)[2]
−243.025 d (retrograde)
Equatorial rotation velocity
6.52 km/h (1.81 m/s)
2.64° (for retrograde rotation)
177.36° (to orbit)[note 1]
North pole right ascension
  •  18h 11m 2s
  • 272.76°
North pole declination
67.16°
Albedo
Surface temp. min mean max
Kelvin 737 K
Celsius 462 °C
Fahrenheit 864 °F
−4.92 to −2.98
9.7″–66.0″
Atmosphere
Surface pressure
92 bar (9.2 MPa)
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 southern hemisphere and makes the axial tilt 177.36°.

Venus is a terrestrial planet because it has a solid, rocky surface like other planets in the inner Solar System. Astronomers have known Venus for thousands of years. The ancient Romans named it after their goddess Venus, goddess of love and beauty.[3]

Venus is the brightest thing in the night sky except for the Moon. It is sometimes called the morning star or the evening star as at some elongations it is easily seen just before the sun comes up in the morning. At other times, it can be seen just after the sun goes down in the evening. Venus comes closer to the Earth than any other planet does.

Venus is sometimes called the sister planet of Earth as they are quite similar in size and gravity. In other ways the planets are very different. Venus' atmosphere (air) is mostly carbon dioxide with clouds of sulphuric acid.[4] Sulphuric acid is a chemical that is poisonous to life. For this it is sometimes known as the Earth's "evil twin".[5][6]

The thick atmosphere makes it hard to see the surface. Until the late twentieth century many thought there might be life there. The pressure on Venus' surface is 92 times that of Earth. Venus is one of only 2 planets in the Solar System (the other being Mercury) that has no moons. Venus spins very slowly on its axis and it spins in the opposite direction to the other planets.

Physical properties

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Radar view of the surface of Venus (Magellan spacecraft)

Venus is a terrestrial planet so, like the Earth, its surface is made of rock. Venus is much hotter than Earth. All the carbon dioxide in the atmosphere acts like a blanket, trapping heat from the Sun. This effect is called the greenhouse effect and it is very strong on Venus. This makes the surface of Venus the hottest of any planet's surface in the Solar System with an estimated average temperature of 480 °C (896.0 °F).[7][8] This is hot enough to melt lead or zinc.

Geography

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Venus has no oceans because it is much too hot for water. Venus' surface is a dry desert. Because of the clouds, only radar can map the surface. It is about 80% smooth, rocky plains, made mostly of basalt. Two higher areas called continents make up the north and south of the planet. The north is called Ishtar Terra and the south is called Aphrodite Terra. They are named after the Babylonian and Greek goddesses of love.[9]

The surface of Venus looks like it has been shaped by volcanic activity. Venus has a lots of volcanoes.[10] The surface of Venus is estimated to be 300–600 million years old.[10][11]

Unlike Earth or Mars, Venus does not have defined highlands or lowlands, and it does not have tectonic plates.

Atmosphere

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Venus' atmosphere is mostly carbon dioxide and nitrogen gas with clouds of sulphuric acid. Because the atmosphere is so thick or dense the pressure is very high. The pressure is 92 times the pressure on Earth, enough to crush many things.

It is impossible to see the planet's surface from space as the thick cloud layer reflects 60% of the light that hits it. The only way scientists are able to see it is by using infrared and ultraviolet cameras and radar.

Scientists believe that billions of years ago, the atmosphere of Venus could have been like Earth's atmosphere. There may have been lots of water on the surface of Venus. But after 600 million to several billion years, the evaporation of the water put greenhouse gases into its atmosphere.[12]

Magnetic field

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In 1967, Venera 4 found that the magnetic field of Venus was much weaker than that of Earth. This magnetic field is induced by an interaction between the ionosphere and the solar wind. Venus' magnetosphere is not strong enough to protect the atmosphere from cosmic rays.[13]

Transit of Venus

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Venus can sometimes be seen passing between the Sun and Earth. Venus looks like a black dot when seen through a special telescope. These passages are called "transits". These "transits" happen in pairs eight years apart. Then it is more than a hundred years to the next pair.

Orbit and rotation

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Orbit of Venus compared to the orbit of the Earth

Venus orbits the Sun at an average distance of about 108 million km (68~ million mi). It completes an orbit every 224.7 days.[14] The rotation of Venus is slow. A Venusian sidereal day is longer than a Venusian year.

List of satellites sent to Venus

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Many man-made satellites have been sent to Venus to study it. They are:

Mariner

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Name Launch Date Country(s) Date of Arrival at Venus Date of Last Radio Signal Did It Work as Planned? Source(s)
Mariner 1 July 22, 1962 United States Never happened because of launch failure July 22, 1962 No [15]
Mariner 2 August 27, 1962 United States December 14, 1962 Janaury 3, 1963 Yes [16][10]
Mariner 5 June 14, 1967 United States June 19, 1967 October 14, 1968 Yes [17][18]
Mariner 10 November 3, 1973 United States February 5, 1974 March 24, 1975 Yes [19][20]

Venera

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Name Launch Date Country(s) Date of Arrival at Venus Date of Last Radio Signal (lander/impactor) Date of Last Radio Signal (orbiter/fly-by craft/kickstage) Did It Work as Planned? Source(s)
Sputnik 7[a] February 4, 1961 Soviet Union Never happened because of failure to leave Low Earth orbit No lander[b] February 26, 1961 No [10]
Sputnik 19 August 25, 1962 Soviet Union Never happened because of failure to leave Low Earth orbit No lander August 28, 1962 No [10]
Venera 1 February 12, 1961 Soviet Union May 19, 1961 No lander February 17, 1961 No [21]
Venera 2 November 12, 1965 Soviet Union February 27, 1966 No lander February 1966 No [22][23]
Venera 3 November 16, 1965 Soviet Union March 1, 1966 February 16, 1966 February 16, 1966 No [24][25]
Venera 4 June 12, 1967 Soviet Union October 18, 1967 No lander October 18, 1967 Yes [26]
Venera 5 January 5, 1969 Soviet Union May 16, 1969 May 16, 1969 May 16, 1969 Yes [27]
Venera 6 January 10, 1969 Soviet Union May 17, 1969 May 17, 1969 May 17, 1969 Yes [28]
Venera 7 August 17, 1970 Soviet Union December 15, 1970 December 15, 1970 December 15, 1970 Landed but rolled and returned very little data [29]
Venera 8 March 27, 1972 Soviet Union July 22, 1972 July 22, 1972 July 22, 1972 Yes [30]
Venera 9 June 8, 1975 Soviet Union October 22, 1975 October 22, 1975 March 22, 1976 Yes [31]
Venera 10 June 14, 1975 Soviet Union October 25, 1975 October 25, 1975 June 1976 [32][10]
Venera 11 September 9, 1978 Soviet Union December 25, 1978 December 25, 1978 February 1980 Yes, small issues with the some of the tools on the mission [33][34]
Venera 12 September 14, 1978 Soviet Union December 21, 1978 December 21, 1978 December 21, 1978 Yes, small issues with the some of the tools on the mission [35]
Venera 13 October 30, 1981 Soviet Union March 1, 1982 March 1, 1982 April 25, 1983 Yes [36]
Venera 14 November 4, 1981 Soviet Union March 5, 1982 March 5, 1982 April 9, 1983 Yes [37][10]
Venera 15 June 2, 1983 Soviet Union October 1983 No lander July 1984 Yes [38][3]
Venera 16 June 7, 1983 Soviet Union October 1983 No lander July 1984 Yes [38][3]
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References and Notes

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  1. Lakdawalla, Emily better (21 September 2009). "Venus Looks More Boring Than You Think It Does". The Planetary Society. Archived from the original on 6 January 2012. Retrieved 4 December 2011.
  2. "Planets and Pluto: Physical Characteristics". NASA. 5 November 2008. Archived from the original on 7 September 2006. Retrieved 26 August 2015.
  3. 3.0 3.1 3.2 3.3 3.4 "Venus". NASA Solar System Exploration. Archived from the original on 2021-10-19. Retrieved 2021-10-19. Cite error: Invalid <ref> tag; name ":2" defined multiple times with different content
  4. "The Atmosphere of Venus". Archived from the original on 2009-03-02. Retrieved 2008-08-19.
  5. Hall, Shannon (June 5, 2019). "Venus is Earth's evil twin — and space agencies can no longer resist its pull". Nature. Archived from the original on June 5, 2021. Retrieved June 6, 2021.
  6. Greenfieldboyce, Nell (June 2, 2021). "NASA Picks Twin Missions To Visit Venus, Earth's 'Evil Twin'". NPR. Archived from the original on June 5, 2021. Retrieved June 6, 2021.
  7. "Venus - an overview". Archived from the original on 2009-09-11. Retrieved 2008-08-20.
  8. "Temperature on the Surface of Venus". Archived from the original on 2008-09-28. Retrieved 2008-08-19.
  9. Batson R.M. & Russell J.F. 1991. Naming the newly found landforms on Venus. Abstracts of the Lunar and Planetary Science Conference, v. 22, p65.
  10. 10.0 10.1 10.2 10.3 10.4 10.5 10.6 Frankel, Charles. (1996). Volcanoes of the solar system. Cambridge: Cambridge University Press. ISBN 0-521-47201-6. OCLC 32969544. Retrieved 2020-09-14. Cite error: Invalid <ref> tag; name ":0" defined multiple times with different content
  11. Nimmo, F.; Mckenzie, D. (1998). "Volcanism and Tectonics on Venus". Annual Review of Earth and Planetary Sciences. 26: 23–51. Bibcode:1998AREPS..26...23N. doi:10.1146/ANNUREV.EARTH.26.1.23. S2CID 862354.
  12. Kasting, James F. (1988). "Runaway and moist greenhouse atmospheres and the evolution of Earth and Venus". Icarus. 74 (3): 472–494. Bibcode:1988Icar...74..472K. doi:10.1016/0019-1035(88)90116-9. PMID 11538226. Archived from the original on 2020-05-31. Retrieved 2020-09-14.
  13. Introduction to space physics. Kivelson, M. G. (Margaret Galland), 1928-, Russell, C. T. (Christopher T.). Cambridge: Cambridge University Press. 1995. ISBN 0-521-45104-3. OCLC 30509600. Retrieved 2020-09-14.{{cite book}}: CS1 maint: others (link)
  14. "Venus Fact Sheet". 2016-03-04. Archived from the original on 2016-03-04. Retrieved 2020-09-14.
  15. "Mariner 1 - NASA Science". science.nasa.gov. Retrieved 2024-05-12.
  16. https://www.jpl.nasa.gov. "Mariner 2 - Venus Missions - NASA Jet Propulsion Laboratory". NASA Jet Propulsion Laboratory (JPL). Retrieved 2024-05-12. {{cite web}}: External link in |last= (help)
  17. https://www.jpl.nasa.gov. "Mariner 5 - Venus Missions - NASA Jet Propulsion Laboratory". NASA Jet Propulsion Laboratory (JPL). Retrieved 2024-05-12. {{cite web}}: External link in |last= (help)
  18. "Mariner 5 - NASA Science". science.nasa.gov. Retrieved 2024-05-12.
  19. "Mariner 10 | National Air and Space Museum". airandspace.si.edu. Retrieved 2024-05-12.
  20. published, Elizabeth Howell (2012-10-31). "Mariner 10: First Mission to Mercury". Space.com. Retrieved 2024-05-12.
  21. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  22. https://www.nasa.gov/wp-content/uploads/2023/04/sp-4524.pdf
  23. "Venera | Soviet Exploration, Technology & Discoveries | Britannica". www.britannica.com. Retrieved 2024-05-12.
  24. "1 March". www.esa.int. Retrieved 2024-05-12.
  25. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  26. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  27. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  28. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  29. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  30. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  31. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  32. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  33. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  34. "Drilling into the Surface of Venus". mentallandscape.com. Retrieved 2024-05-12.
  35. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  36. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  37. "NASA - NSSDCA - Spacecraft - Details". nssdc.gsfc.nasa.gov. Retrieved 2024-05-12.
  38. 38.0 38.1 "Venera 15 & 16". solarviews.com. Retrieved 2024-05-12.

Other websites

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