Editing Venus (section)

== 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 where [[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 the lowest [[gravitational potential]] difference to Earth than any other planet, needing the [[Delta-v budget|lowest delta-v]] to transfer between them.<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>