Editing Jupiter (section)

=== Galilean moons ===
{{Main|Galilean moons}}
The moons discovered by Galileo—Io, Europa, Ganymede, and Callisto—are among the largest in the Solar System. The orbits of Io, Europa, and Ganymede form a pattern known as a [[Laplace resonance]]; for every four orbits that Io makes around Jupiter, Europa makes exactly two orbits and Ganymede makes exactly one. This resonance causes the gravitational effects of the three large moons to distort their orbits into elliptical shapes, because each moon receives an extra tug from its neighbours at the same point in every orbit it makes. The [[tidal force]] from Jupiter, on the other hand, works to [[Tidal circularization|circularize]] their orbits.<ref>{{cite journal | last1=Musotto | first1=S. | last2=Varadi | first2=F. | last3=Moore | first3=W. B. | last4=Schubert | first4=G. |title=Numerical simulations of the orbits of the Galilean satellites |url=http://cat.inist.fr/?aModele=afficheN&cpsidt=13969974 |journal=Icarus |year=2002 |volume=159 |issue=2 |pages=500–504 |doi=10.1006/icar.2002.6939 |bibcode=2002Icar..159..500M |access-date=February 19, 2007 |archive-date=August 10, 2011 |archive-url=https://web.archive.org/web/20110810071532/http://cat.inist.fr/?aModele=afficheN&cpsidt=13969974 |url-status=dead }}</ref>

The [[Orbital eccentricity|eccentricity]] of their orbits causes regular flexing of the three moons' shapes, with Jupiter's gravity stretching them out as they approach it and allowing them to spring back to more spherical shapes as they swing away. The [[friction]] created by this tidal flexing [[Tidal acceleration#Tidal heating|generates heat]] in the interior of the moons.<ref name=Eccen304>{{cite book|page=304|title=The Cambridge Guide to the Solar System|date=March 3, 2011|last1=Lang|first1=Kenneth R.|publisher=Cambridge University Press|isbn=978-1-139-49417-5}}</ref> This is seen most dramatically in the [[Io (moon)#Volcanism|volcanic activity]] of Io (which is subject to the strongest tidal forces),<ref name="Eccen304"/> and to a lesser degree in the geological youth of [[Europa (moon)#Surface features|Europa's surface]], which indicates recent resurfacing of the moon's exterior.<ref>{{cite book|page=446|title=Encyclopedia of the Solar System|year=2006|last1=McFadden|first1=Lucy-Ann|last2=Weissmann|first2=Paul|last3=Johnson|first3=Torrence|publisher=Elsevier Science|isbn=978-0-08-047498-4}}</ref>

{| style="width:550px; margin:0 auto;" cellpadding=0 cellspacing=0
|
{| class="wikitable" style="text-align:right; margin:0 auto;"
|+ The Galilean moons compared to the Earth's [[Moon]]
|-
! rowspan=2 | Name
! rowspan=2 | [[Help:IPA/English|IPA]]
! colspan=2 | Diameter
! colspan=2 | Mass
! colspan=2 | Orbital radius
! colspan=2 | Orbital period
|-
! km
! ''D''<sub>☾</sub>
! kg
! ''M''<sub>☾</sub>
! km
! ''a''<sub>☾</sub>
! days
! ''T''<sub>☾</sub>
|-
! [[Io (moon)|Io]]
| align=left | {{small|{{IPAc-en|ˈ|aɪ|.|oʊ}}}}
| 3,643
| 1.05
| 8.9×10<sup>22</sup>
| 1.20
| 421,700
| 1.10
| 1.77
| 0.07
|-
! [[Europa (moon)|Europa]]
| align=left | {{small|{{IPAc-en|j|ʊ|ˈ|r|oʊ|p|ə}}}}
| 3,122
| 0.90
| 4.8×10<sup>22</sup>
| 0.65
| 671,034
| 1.75
| 3.55
| 0.13
|-
! [[Ganymede (moon)|Ganymede]]
| align=left | {{small|{{IPAc-en|ˈ|ɡ|æ|n|ɪ|m|iː|d}}}}
| 5,262
| 1.50
| 14.8×10<sup>22</sup>
| 2.00
| 1,070,412
| 2.80
| 7.15
| 0.26
|-
! [[Callisto (moon)|Callisto]]
| align=left | {{small|{{IPAc-en|k|ə|ˈ|l|ɪ|s|t|oʊ}}}}
| 4,821
| 1.40
| 10.8×10<sup>22</sup>
| 1.50
| 1,882,709
| 4.90
| 16.69
| 0.61
|}
|-
| [[File:The Galilean satellites (the four largest moons of Jupiter).tif|frameless|561px|center|The Galilean satellites in false colour. From left to right, in order of increasing distance from Jupiter: [[Io (moon)|Io]], [[Europa (moon)|Europa]], [[Ganymede (moon)|Ganymede]], [[Callisto (moon)|Callisto]].]]
|-
| style="font-size:0.9em; text-align:center;" | The Galilean satellites [[Io (moon)|Io]], [[Europa (moon)|Europa]], [[Ganymede (moon)|Ganymede]], and [[Callisto (moon)|Callisto]] (in order of increasing distance from Jupiter) in false colour
|}