Editing Miranda (moon) (section)

== Geography ==
Miranda has a unique surface.<ref name=Brahic2010_195>{{harvsp|A. Brahic|2010|p=195|id=Brahic2010}}</ref>{{sfn|Thomas|1988|p=427}} Among the geological structures that cover it are fractures, faults, valleys, craters, ridges, gorges, depressions, cliffs, and terraces.<ref name=Brahic2010_197>{{harvsp|A. Brahic|2010|p=197|id=Brahic2010}}</ref><ref name=Encrenaz2010_130>{{harvnb|Encrenaz|2010|p=130}}</ref> This moon is a mosaic of highly varied zones. Some areas are older and darker. As such, they bear numerous impact craters, as is expected of a small inert body.<ref name=Brahic2010_195/> Other regions are made of rectangular or ovoid strips. They feature complex sets of parallel ridges and rupes ([[Fault scarp|fault scarps]]) as well as numerous outcrops of bright and dark materials, suggesting an exotic composition.{{sfn|Smith|1986|p=43}} This moon is most likely composed only of water ice on the surface, as well as silicate rocks and other more or less buried organic compounds.{{sfn|Smith|1986|p=43}}

{| class="wikitable"
|+ Main geological structures visible on the known part of Miranda<ref name=usgs_ref>{{ cite web | url= https://planetarynames.wr.usgs.gov/AdvancedSearch | website= Gazetteer of Planetary Nomenclature | publisher= [[United States Geological Survey]] | title= Advanced nomenclature search | access-date= 4 June 2024 | author= ((Astrogeology Science Center)) }} Direct link to all official names of features on Miranda unavailable due to target site structure. Select "Miranda" from "Target" dropdown to view.</ref><br />(all named in reference to works by [[William Shakespeare]])
!  Name  !! Type !! Length<br />(diameter)<br />(km) !! Latitude<br />(°) !! Longitude<br />(°) !! Origin of the name
|-
| Mantua Regio
| rowspan="4"|[[Regio (astronomy)|Regiones]]|| 399 || −39.6 || 180.2 ||Italian region of part of the plot of ''[[The Two Gentlemen of Verona]]''
|-
| Ephesus Regio || 225 || −15 || 250 ||The twins' house in [[Turkey]] in ''[[The Comedy of Errors]]''
|-
| Sicilia Regio || 174 || −30 || 317.2 ||Italian region of the plot of ''[[The Winter's Tale]]''
|-
| Dunsinane Regio || 244 || −31.5 || 11.9 || Hill in [[Scotland]] at which [[Macbeth (Shakespeare)|Macbeth]] is defeated
|-
| Arden Corona
| rowspan="3" | [[Corona (planetary geology)|Coronae]]|| 318 || −29.1 || 73.7 || Forest in England where the plot of ''[[As You Like It]]'' takes place
|-
| Elsinore Corona || 323 || −24.8   || 257.1 || Castle in [[Denmark]] that is the setting for ''[[Hamlet]]''
|-
| [[Inverness Corona]] || 234 || −66.9   || 325.7 || Macbeth's castle in [[Scotland]]
|-
| Argier Rupes
| rowspan="2"|[[Rupes]]|| 141 || −43.2 || 322.8 || Region of [[France]] where the beginning of the plot of ''[[The Tempest]]'' takes place
|-
| [[Verona Rupes]]  || 116 || −18.3   || 347.8 || Italian city where the plot of ''[[Romeo and Juliet]]'' takes place
|-
| [[Alonso (crater)|Alonso]]
| rowspan="7" | [[Impact crater]] || 25 || −44 || 352.6 || King of Naples in ''The Tempest''
|-
| Ferdinand || 17 || −34.8   || 202.1 || Son of the King of Naples in ''The Tempest''
|-
| Francisco || 14 || −73.2 || 236   || A lord of Naples in ''The Tempest''
|-
| Gonzalo || 11 || −11.4 || 77 || An honest old councilor from Naples in ''The Tempest''
|-
| Prospero || 21 || −32.9 || 329.9   || Legitimate Duke of Milan in ''The Tempest''
|-
| Stephano || 16 || −41.1 || 234.1   || A drunken butler in ''The Tempest''
|-
| Trinculo || 11 || −63.7 || 163.4   || A jester in ''The Tempest''
|}

=== Regiones ===
The [[Regio (astronomy)|regiones]] identified on the images taken by the ''[[Voyager 2]]'' probe are named "Mantua Regio", "Ephesus Regio", "Sicilia Regio", and "Dunsinane Regio".<ref name=usgs_ref/> They designate major regions of Miranda where hilly terrain and plains follow one another, more or less dominated by ancient impact craters.{{sfn|Smith|1986|p=60}} Normal [[Fault (geology)|faults]] also mark these ancient regions. Some [[Escarpment|escarpments]] are as old as the formation of the regions while others are much more recent and appear to have formed after the coronae.{{sfn|Smith|1986|p=61}} These faults are accompanied by [[graben]]s characteristic of ancient tectonic activity.{{sfn|Smith|1986|p=60}} The surface of these regions is fairly uniformly dark. However, the cliffs bordering certain impact craters reveal, at depth, the presence of much more luminous material.{{sfn|Smith|1986|p=60}}

=== Coronae ===
[[File:Geographic Sketch Map Of Miranda.png|thumb|right|Illustration of the positions of the main geological structures on an image of Miranda]]
Miranda is one of very few objects in the Solar system to have [[Corona (planetary geology)|crowns]] (also called coronae). The three known coronae observed on Miranda are named Inverness Corona near the south pole, Arden Corona at the [[Solar apex|apex]] of the moon's orbital motion, and Elsinore Corona at the antapex.<ref name=usgs_ref/> The highest [[albedo]] contrasts on Miranda's surface occur within the Inverness and Arden coronae.{{sfn|Smith|1986|p=59}}

==== Inverness Corona ====
[[File:InvernessCorona.png|thumb|The Inverness Corona is characterized by its white central "chevron". The crater Alonso is visible in the upper right, as well as the cliffs of Argier Rupes in the upper left.]]
[[Inverness Corona]] is a trapezoidal region of approximately {{cvt|200|km}} on a side which lies near the south pole. This region is characterized by a central geological structure which takes the shape of a luminous chevron,<ref name=Plescia1987_445>{{harvsp|J. B. Plescia|1987|p=445|id=Plescia1987}}</ref> a surface with a relatively high albedo, and a series of gorges which extend northwards from a point near the pole.<ref name=Plescia1987_446>{{harvsp|J. B. Plescia|1987|p=446|id=Plescia1987}}</ref> At a latitude of around −55°, north-south oriented gorges tend to intersect with others, which follow an east-west direction.<ref name=Plescia1987_446/> The outer boundary of Inverness, as well as its internal patterns of ridges and bands of contrasting [[albedo]]s, form numerous salient angles.{{sfn|Smith|1986|p=59}} It is bounded on three sides (south, east and north) by a complex system of faults. The nature of the west coast is less clear, but may also be tectonic. Within the crown, the surface is dominated by parallel gorges spaced a few kilometers apart.<ref name=Plescia1987_445-446>{{harvsp|J. B. Plescia|1987|p=445–446|id=Plescia1987}}</ref> The low number of [[Impact crater|impact craters]] indicates that Inverness is the youngest among the three coronae observed on the surface of Miranda.<ref name=Plescia1987_442>{{harvsp|J. B. Plescia|1987|p=442|id=Plescia1987}}</ref>

==== Arden Corona ====
Arden Corona, present in the front hemisphere of Miranda, extends over approximately {{cvt|300|km}} from east to west. The other dimension, however, remains unknown because the terrain extended beyond the [[Terminator (solar)|terminator]] (on the hemisphere plunged into night) when ''Voyager 2'' photographed it. The outer margin of this corona forms parallel and dark bands which surround in gentle curves a more clearly rectangular core at least {{cvt|100|km}} wide. The overall effect has been described as an ovoid of lines.{{sfn|Smith|1986|p=59}} The interior and belt of Arden show very different morphologies. The interior topography appears regular and soft. It is also characterized by a mottled pattern resulting from large patches of relatively bright material scattered over a generally dark surface. The stratigraphic relationship between the light and dark marks could not be determined from the images provided by ''Voyager 2''. The area at the margin of Arden is characterized by concentric albedo bands which extend from the western end of the crown where they intersect crateriform terrain (near 40° longitude) and on the side east, where they extend beyond the, in the northern hemisphere (near 110° longitude).<ref name=Plescia1987_444>{{harvsp|J. B. Plescia|1987|p=444|id=Plescia1987}}</ref> The contrasting albedo bands are composed of outer fault scarp faces.<ref name=Plescia1987_444/> This succession of escarpments gradually pushes the land into a deep hollow along the border between Arden and the crateriform terrain called Mantua Regio.<ref name=Plescia1987_444/> Arden was formed during a geological episode which preceded the formation of Inverness but which is contemporary with the formation of Elsinore.<ref name=Plescia1987_442/>

==== Elsinore Corona ====
Elsinore Corona is the third corona, which was observed in the rear hemisphere of Miranda, along the [[Terminator (solar)|terminator]]. It is broadly similar to Arden in size and internal structure. They both have an outer belt about {{cvt|100|km}} wide, which wraps around an inner core.{{sfn|Smith|1986|p=59}} The [[topography]] of the core of Elsinore consists of a complex set of intersections of troughs and bumps which are truncated by this outer belt which is marked by roughly concentric linear ridges. The troughs also include small segments of rolling, cratered terrain.{{sfn|Smith|1986|p=59}} Elsinore also presents segments of furrows, called "''[[Sulcus (geology)|sulcus]]''",<ref name=usgs_ref/> comparable to those observed on [[Ganymede (moon)|Ganymede]].{{sfn|Smith|1986|p=59}}

=== Rupes ===
[[File:Miranda scarp.jpg|thumb|Close-up view of [[Verona Rupes]], a cliff {{cvt|5 to 10|km}} high.{{sfn|PIA00044}}]]

Miranda also features enormous [[escarpment|escarpments]] that can be traced across the moon. Some of them are older than the coronae, others younger. The most spectacular fault system begins at a deep valley visible at the terminator.

This network of faults begins on the northwest side of Inverness where it forms a deep gorge on the outer edge of the ovoid which surrounds the crown.{{sfn|Smith|1986|p=59}} This geological formation is named "''Argier Rupes''".<ref name=usgs_ref/>

The most impressive fault then extends to the terminator, extending from the top of the central "chevron" of Inverness.{{sfn|Smith|1986|p=59}} Near the terminator, a gigantic luminous cliff, named [[Verona Rupes]],<ref name=usgs_ref/> forms complex [[graben]]s. The fault is approximately {{cvt|20|km}} wide, the graben at the bright edge is 10 to {{cvt|15|km}} deep.{{sfn|Smith|1986|p=59}} The height of the sheer cliff is 5 to {{cvt|10|km}}.{{sfn|Smith|1986|p=59}} Although it could not be observed by the ''Voyager 2'' probe on the face immersed in the [[polar night]] of Miranda, it is probable that this geological structure extends beyond the terminator in the northern hemisphere.<ref name=Plescia1987_442 />

=== Impact craters ===
During the close flyby of ''Voyager 2'' in January 1986, only the craters on the southern hemisphere of Miranda could be observed. They generally had diameters of over {{cvt|500|m}}, representing the limit of resolution of the digital images transmitted by the probe during its flight.<ref name=Plescia1987_442 /> These craters have very varied morphologies. Some have well-defined borders and are sometimes surrounded by ejecta deposits characteristic of [[impact crater|impact craters]]. Others are very degraded and sometimes barely recognizable, as their topography has been altered.<ref name=Plescia1987_443>{{harvsp|J. B. Plescia|1987|p=443|id=Plescia1987}}</ref> The age of a crater does not give an indication of the date of formation of the terrain it marked. On the other hand, this date depends on the number of craters present on a site, regardless of their age.<ref name=Plescia1987_448>{{harvsp|J. B. Plescia|1987|p=448|id=Plescia1987}}</ref> The more impact craters a terrain has, the older it is. Scientists use these as "planetary chronometers"; they count observed craters to date the formation of the terrain of inert natural satellites devoid of atmospheres, such as [[Callisto (moon)|Callisto]].<ref name=Brahic2010_185-186>{{harvsp|A. Brahic|2010|p=185–186|id=Brahic2010}}</ref>

No multiple ring crater, nor any complex crater with a central peak, has been observed on Miranda.<ref name=Plescia1987_443/> Simple craters, that is to say whose cavity is bowl-shaped, and transitional craters (with a flat bottom) are the norm, with their diameter not correlated to their shape.<ref name=Plescia1987_443/> Thus simple craters of more than {{cvt|15|km}} are observed while elsewhere transitional craters of {{cvt|2.5|km}} have been identified.<ref name=Plescia1987_443/> Ejecta deposits are rare, and are never associated with craters larger than {{cvt|15|km}} in diameter.<ref name=Plescia1987_443/> The ejecta that sometimes surround craters with a diameter less than {{cvt|3|km}} appear systematically brighter than the material surrounding them. On the other hand, ejecta associated with craters of size between {{cvt|3|km}} and {{cvt|15|km}} are generally darker than what surrounds them (the albedo of the ejecta is lower than that of the matter surrounding them).<ref name=Plescia1987_443/> Finally, some ejecta deposits, associated with diameters of all sizes, have an albedo comparable to that of the material on which they rest.<ref name=Plescia1987_443/>

==== In regiones ====
In some regiones, and particularly in those of the visible part of the anti-Uranian hemisphere (which continually turns its back on the planet), craters are very frequent. They are sometimes stuck to each other with very little space between each one.<ref name=Plescia1987_443/> Elsewhere, craters are less frequent and are separated by large, weakly undulated surfaces.<ref name=Plescia1987_443/> The rim of many craters is surrounded by luminous material while streaks of dark material are observed on the walls which surround the bottom of the craters.<ref name=Plescia1987_443/> In Matuna Regio, between the craters Truncilo and Fransesco, there is a gigantic circular geological structure of {{cvt|170|km}} in diameter which could be a [[Impact crater|basin impact]] very significantly degraded.<ref name=Plescia1987_443/> These findings suggest that these regions contain a shiny material at shallow depth, while a layer of dark material (or a material which darkens upon contact with the external environment) is present, at greater depth.<ref name=Plescia1987_444/>

==== In coronae ====
Craters are statistically up to ten times less numerous in the coronae than in the anti-Uranian regions, which indicates that these formations are younger.<ref name=Plescia1987_449>{{harvsp|J. B. Plescia|1987|p=449|id=Plescia1987}}</ref>

The density of impact craters could be established for different areas of Inverness, and made it possible to establish the age of each.<ref name=Plescia1987_450>{{harvsp|J. B. Plescia|1987|p=450|id=Plescia1987}}</ref> Considering these measurements, the entire geological formation was formed in a relative unit of time.<ref name=Plescia1987_451>{{harvsp|J. B. Plescia|1987|p=451|id=Plescia1987}}</ref> However, other observations make it possible to establish that the youngest zone, within this crown, is the one which separates the "chevron", from Argier Rupes.<ref name=Plescia1987_451/>

The density of impact craters in the core and in the Arden belt is statistically similar.<ref name=Plescia1987_450/> The two distinct parts of this formation must therefore have been part of a common geological episode.<ref name=Plescia1987_450/> Nevertheless, the superposition of craters on bands of the central core of Arden indicates that its formation preceded that of the scarps which surround it.<ref name=Plescia1987_450/> The data from the impact craters can be interpreted as follows: the interior and marginal zones of the corona, including most of the albedo bands, were formed during the same period of time.<ref name=Plescia1987_450/> Their formation was followed by later tectonic developments which produced the high-relief fault scarps observed along the edge of the crown near longitude 110°.<ref name=Plescia1987_450/>

The density of impact craters seems the same in the structure surrounding Elsinore as in its central core.<ref name=Plescia1987_452>{{harvsp|J. B. Plescia|1987|p=452|id=Plescia1987}}</ref> The two zones of the crown seem to have formed during the same geological period, but other geological elements suggest that the perimeter of Elsinore is younger than its core.<ref name=Plescia1987_452/>

==== Other observations ====
The number of craters should be higher in the hemisphere at the apex of the orbital movement than at the antapex.<ref name=Plescia1987_454>{{harvsp|J. B. Plescia|1987|p=454|id=Plescia1987}}</ref> However, it is the anti-Uranian hemisphere which is densest in craters.<ref name=Plescia1987_455>{{harvsp|J. B. Plescia|1987|p=455|id=Plescia1987}}</ref> This situation could be explained by a past event having caused a reorientation of Miranda's axis of rotation by 90° compared to that which is currently known.<ref name=Plescia1987_455/> In this case, the paleoapex hemisphere of the moon would have become the current anti-Uranian hemisphere.<ref name=Plescia1987_455/> However, the count of impact craters being limited to the southern hemisphere only, illuminated during the passage of the Voyager 2 probe, it is possible that Miranda has experienced a more complex reorientation and that its paleoapex is located somewhere in the northern hemisphere, which has not yet been photographed.<ref name=Plescia1987_455/>