Editing Mercury (planet)

{{Infobox Planet
| bgcolour = #D8BBA6
| name = Mercury
| symbol = [[File:mercury symbol.svg|25px|Astronomical symbol of mercury]]
| image = Mercury in color - Prockter07 centered.jpg
| caption = Mercury
| orbit_ref =<ref name=horizons>{{cite web
  | date=April 7, 2008 | first=Donald K. | last=Yeomans
  | url=http://ssd.jpl.nasa.gov/?horizons
  | title=HORIZONS System
  | publisher=NASA JPL | accessdate=2008-04-07 }}</ref>
| epoch = J2000
| aphelion = 69,816,900 km<br />0.466&nbsp;697 [[Astronomical unit|AU]]
| perihelion = 46,001,200 km<br />0.307&nbsp;499 AU
| semimajor = 57,909,100 km<br />0.387&nbsp;098 AU
| eccentricity = 0.205&nbsp;630<ref name="nssdcMercury" />
| period = 87.969&nbsp;1 [[day|d]]<br />(0.240&nbsp;846 [[julian year (astronomy)|a]])
| synodic_period = 115.88&nbsp;d<ref name="nssdcMercury">{{cite web|title=Mercury Fact Sheet|url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/mercuryfact.html|publisher=[[NASA]] Goddard Space Flight Center | date=November 30, 2007 |accessdate=2008-05-28}}</ref>
| avg_speed = 47.87 km/s<ref name="nssdcMercury" />
| inclination = 7.005° to [[Ecliptic]]<br />3.38° to [[Ecliptic#Ecliptic and planets|Sun’s equator]]<br />6.34° to [[Invariable plane]]<ref name=meanplane>{{cite web
  |date=2009-04-03
  |title=The MeanPlane (Invariable plane) of the Solar System passing through the barycenter
  |url=http://home.comcast.net/~kpheider/MeanPlane.gif
  |accessdate=2009-04-03}} (produced with [http://chemistry.unina.it/~alvitagl/solex/ Solex 10] written by Aldo Vitagliano; see also [[Invariable plane]])</ref>
| asc_node = 48.331°
| arg_peri = 29.124°
| mean_anomaly = 174.796°
| satellites = None

diameter = 4,880 km
| mean_radius = 2,439.7&nbsp;±&nbsp;1.0&nbsp;km<ref name=nasa>{{cite web
  | date=May 28, 2009 | first=Kirk | last=Munsell
  | author2=Smith, Harman; Harvey, Samantha
  | url=http://solarsystem.nasa.gov/planets/profile.cfm?Object=Mercury&Display=Facts
  | title=Mercury: Facts & Figures
  | work=Solar System Exploration
  | publisher=NASA | accessdate=2008-04-07 }}
</ref><ref name=Seidelmann2007>{{cite journal
  | last= Seidelmann| first= P. Kenneth
  | author2= Archinal, B. A.; A’hearn, M. F.; et al.
  | title= Report of the IAU/IAGWorking Group on cartographic coordinates and rotational elements: 2006
  | journal= Celestial Mechanics and Dynamical Astronomy
  | volume=90 | pages=155–180 | year=2007
  | doi=10.1007/s10569-007-9072-y
  | url=http://adsabs.harvard.edu/doi/10.1007/s10569-007-9072-y
  | accessdate=2007-08-28 }}</ref><br />0.3829 Earths
| flattening = < 0.0006<ref name=Seidelmann2007/> <!-- calculated from data in ref name=Seidelmann2007 -->
| surface_area = 7.48{{e|7}}&nbsp;km²<br />0.147 Earths<ref name=nasa/>
| volume = 6.083{{e|10}}&nbsp;km³<br />0.054 Earths<ref name=nasa/>
| mass = 3.3022{{e|23}}&nbsp;kg<br />0.055 Earths<ref name=nasa/>
| density = 5.427&nbsp;g/cm³<ref name=nasa/>
| surface_grav = 3.7&nbsp;[[Acceleration|m/s²]]<br />0.38 [[g-force|g]]<ref name=nasa/>
| escape_velocity = 4.25&nbsp;km/s<ref name=nasa/>
| sidereal_day = 58.646 day<br />1407.5&nbsp;[[hour|h]]<ref name=nasa/>
| rot_velocity = {{cvt|10.892|km/h|m/s}}
| axial_tilt = 2.11′&nbsp;±&nbsp;0.1′<ref name=Margot2007>{{cite journal |last=Margot |first=L.J. |others=Peale, S.J.; Jurgens, R.F.; Slade, M.A.; Holin, I.V. |title=Large Longitude Libration of Mercury Reveals a Molten Core| journal=Science| year=2007 | volume=316 | pages=710–714| doi=10.1126/science.1140514
| url=http://adsabs.harvard.edu/abs/2007Sci...316..710M| pmid=17478713}}</ref>
| right_asc_north_pole = 18 h 44 min 2 s<br />281.01°<ref name="nssdcMercury" />
| declination = 61.45°<ref name="nssdcMercury" />
| albedo = 0.119 ([[Bond albedo|bond]])<br />
0.106 ([[Geometric albedo|geom.]])<ref name="nssdcMercury" />
| magnitude = up to −1.9<ref name="nssdcMercury" />
| angular_size = 4.5" – 13"<ref name="nssdcMercury" />

| temp_name1 = 0°N, 0°W <!-- Vasavada et al. 1999-->
| min_temp_1 = 100 K
| mean_temp_1 = 340 K
| max_temp_1 = 700 K
| temp_name2 = 85°N, 0°W
| min_temp_2 = 80 K
| mean_temp_2 = 200 K
| max_temp_2 = 380 K
| pronounce =  {{IPA-en|ˈmɜrkjəri||en-us-Mercury.ogg}}
| adjectives = Mercurian,<ref>{{cite web |url=https://en.oxforddictionaries.com/definition/mercurian |title=Mercurian |publisher=Oxford University Press |accessdate=2016-12-15}}</ref>
| | atmosphere_composition = 42% Molecular [[oxygen]]<br />29.0% [[sodium]]<br />22.0% [[hydrogen]]<br />6.0% [[helium]]<br />0.5% [[potassium]]<br />Trace amounts of [[argon]], [[nitrogen]], [[carbon dioxide]], [[Water|water vapor]], [[xenon]], [[krypton]], & [[neon]]<ref name="nssdcMercury" />
}}

'''Mercury''' is the smallest [[planet]] in the [[Solar System]].<ref>{{cite web |url= http://nineplanets.org/mercury.html |title=Mercury  l  Mercury facts, pictures and information. |first= |last= |work= nineplanets.org |year=2011 |origyear= last update |accessdate=7 March 2012}}</ref><ref>{{cite web |url= http://www.bbc.co.uk/science/space/solarsystem/sun_and_planets/mercury_(planet) |title=BBC Solar System - Mercury: A tortured world close to our blazing Sun |first= |last= |work= bbc.co.uk |year=2012 |origyear= last update |accessdate=7 March 2012}}</ref><ref>[[Pluto]] was once thought to be the smallest, but, as of 2006, Pluto is now known as a [[dwarf planet]].</ref>  It is the closest planet to the sun.<ref name=sciencefact>{{citation|title=Space Science: Journey to the Innermost Planet|newspaper=Scientific American|pages=26-31|date=March 2011|location=New York|volume=304|issue=3|author1=Murchie, Scott L.|author2=Vervack Jr., Ronald J.|author3=Anderson, Brian J.}}</ref> It makes one [[orbit|trip]] around the Sun once every 87.969 days.<ref name="nssdcMercury" /><ref>[http://image.gsfc.nasa.gov/poetry/venus/VTratesExt.html]</ref> Mercury is bright when it is visible from [[Earth]], ranging from −2.0 to 5.5 in [[apparent magnitude]]. It cannot be easily seen as it is usually too close to the Sun.  Because Mercury is normally lost in the glare of the Sun, Mercury can only be seen in the morning or evening [[twilight]]<ref name="hiw">{{cite book|title=How it Works Book of Space|date=2010|publisher=Imagine Publishing|isbn=9781906078829|page=36-37}}</ref> or during a [[solar eclipse]].

Less is known about Mercury than about other planets of our Solar System.  [[Telescope]]s on the Earth show only a small, bright crescent, and putting a [[Satellite (artificial)|satellite]] in orbit around it is difficult.  The first of two [[spacecraft]] to visit the planet was [[Mariner 10|Mariner&nbsp;10]],<ref>[http://nssdc.gsfc.nasa.gov/nmc/masterCatalog.do?sc=1973-085A]</ref> which mapped only about 45% of the planet’s surface from 1974 to 1975. The second is the [[MESSENGER]] spacecraft, which finished mapping the planet in March 2013.

Mercury looks like Earth's [[Moon]].  It has many [[crater]]s and areas of smooth plains, no moons around it and no [[atmosphere]] as we know it.  However, Mercury does have an extremely thin atmosphere, known as an [[exosphere]].<ref name=sciencefact />  Unlike Earth's moon, Mercury has a large [[iron]] [[planetary core|core]], which gives off a [[magnetic field]] about 1% as strong as that of the [[Earth]].<ref>{{cite web |url=http://www-spc.igpp.ucla.edu/personnel/russell/papers/merc_mag/|title=Mercury magnetic field|publisher=C. T. Russell & J. G. Luhmann|accessdate=2007-03-16}}</ref> It is a very dense planet due to the large size of its core. Surface temperatures can be anywhere from about 90 to {{nowrap|700 [[Kelvin|K]]}} (−183&nbsp;°C to 427&nbsp;°C, −297&nbsp;°F to 801&nbsp;°F),<ref name="ESAs&t">{{cite web|url=http://sci.esa.int/science-e/www/category/index.cfm?fcategoryid=4586|title=Background Science|publisher=European Space Agency|accessdate=2008-05-23}}</ref> with the [[subsolar point]] being the hottest and the bottoms of craters near the [[Geographical pole|poles]] being the coldest.

Known sightings of Mercury date back to at least the first millennium BC. Before the 4th century BC, Greek [[astronomers]] thought that Mercury was two different objects: one able to be seen only at sunrise, which they called [[Apollo]]; the other that was only able to be seen at sunset, which they called [[Hermes]].<ref name="Dunne">{{cite book|title=The Voyage of Mariner&nbsp;10 — Mission to Venus and Mercury|author=Dunne, J. A. and Burgess, E.|chapterurl=http://history.nasa.gov/SP-424/ch1.htm|publisher=NASA History Office|year=1978|chapter=Chapter One|url=http://history.nasa.gov/SP-424/}}</ref> The English name for the planet is from the [[Ancient Rome|Romans]], who named it after the Roman [[Roman mythology|god]] [[Mercury (mythology)|Mercury]], which they thought to be the same as the Greek god [[Hermes]]. The symbol for Mercury is based on Hermes' [[Staff (stick)|staff]].<ref>{{cite book|title=Astronomy: A Textbook|first=John Charles|last=Duncan|year=1946|publisher=Harper & Brothers|pages=125|quote=The symbol for Mercury represents the Caduceus, a wand with two serpents twined around it, which was carried by the messenger of the gods.}}</ref>

Even though Mercury is the closest planet to the Sun, it is not the warmest. This is because it has no [[greenhouse effect]], so energy received from the Sun is radiated into space during Hermitian nights. The hottest planet, because of its greenhouse effect, is [[Venus]].<ref>{{cite web | url=http://www.bbc.co.uk/newsround/14143062 | title=CBBC Newsround | publisher=British Broadcasting Corporation | accessdate=February 04, 2012}}</ref>

==Spin-Orbit Coupling==
Mercury was long considered to have a synchronous rotation, its orbital period being equal to its rotation period, as does the [[Moon]].  Radar studies by Pettengill and Dyce using the [[Arecibo Observatory]] of [[Cornell University]] showed in the 1960's, however, that it is locked in a 3:2 mode, the orbital period  being 88 days whereas the rotational period being 59 days.

== Inside Mercury ==
Mercury is one of four inner planets in the [[Solar System]], <a href="https://factshungry.com/interesting-facts-of-mercury/amp/">mercury</a>, Venus, [[Earth]], and Mars, and like these has a rocky body.  With Pluto now demoted to minor planet status, Mercury is the smallest planet in the Solar System, with a [[radius]] of {{cvt|2439.7|km|mi}}.<ref name="nssdcMercury" /> Mercury is even smaller than some of the largest moons in the solar system, such as [[Ganymede]] and [[Titan (moon)|Titan]]. However, because these moons have a large water ice component, it has a greater mass than the largest moons in the solar system. Mercury is made of about 70% [[metal]]lic and 30% [[silicate]] material.<ref name="strom" >{{cite book |title=Exploring Mercury: The Iron Planet |last=Strom |first=Strom, Robert G.
 |author2=Sprague, Ann L. |year=2003 |page=52
 |isbn= 1852337311}}</ref> Mercury's [[[https://factshungry.com/interesting-facts-of-mercury/amp/ density]]] is the second highest in the Solar System at 5.427&nbsp;g/cm³, only a little bit less than Earth’s.<ref name="nssdcMercury" />  Some water ice has been detected on Sun-shielded sides of craters on Mercury.

== Related pages ==
===Planets===
*[https://factshungry.com/interesting-facts-of-mercury/amp/ 
 mercury ]
*[[Venus]]
*[[Earth]]
*[[Mars]]
*[[Jupiter]]
*[[Saturn]]
*[[Uranus]]
*[[Neptune]]

== References ==
{{reflist}}

== Other websites ==
[https://factshungry.com/interesting-facts-of-mercury/amp/  www.factshungry.com]

[https://solarviews.com/eng/mercury.html www.solarviews.com]

[http://www.planetfacts.net/Mercury-Facts.html www.planetfacts.net]