ICA Multilingual Glossary
Please note that this Glossary has been updated several times since 2001. The glossary shown here is an archived version from 2001.
Maps of planetary objects has become an important new product derived from the space investigations of several nations. These planetary maps are used for both research activities and for dissemination of planetary science results to the general populace of nations throughout the world. The terms used to describe physical and geographical objects on these planetary objects sometimes do not translate to the same meaning in different languages. In an attempt to aid international users of planetary maps in obtaining a correct interpretation of the terrains portrayed on these maps, the ICA Commission on Planetary Cartography has initiated a project to collect terms relevant to planetary maps along with their interpretations in various languages. We are dependent upon obtaining the terms and their definitions from users of planetary maps throughout the international community, and we encourage anyone to submit mapping terms with inconsistent interpretations to either of the authors listed above. A glossary of planetary mapping terms and their interpretations in several languages will be posted on the Commission web site (http://www.nasm.si.edu/research/ceps/ica). As an example of the potential problem resulting from a misinterpretation of terms, we note that the numerical term “billion” has two distinct meanings in wide usage: one billion means a thousand million (one times ten to the 9th power) in the United States and France, but it means a million million (one times ten to the 12th power) in Great Britain and Germany (Webster’s Dictionary). This difference could cause a significant error in map scale interpretation. Map descriptions can have similar discrepancies in their usage. For example, a “topographic map” in English and German usage has contours representing terrain elevations, but in Russia this same product is called a “hypsometric map”. The glossary should aid in clarifying cases of potential confusion among mapping terms, as well as provide multiple language expressions for common mapping features (“mountain” in English is “berg” in Dutch and German, “montana” in Spanish, and “montagne” in French).
This paper provides an introduction to an ongoing project by the ICA Commission on Planetary Cartography. The Commission on Planetary Cartography has committed to compile a glossary of terms frequently used on planetary maps, as well as a list of terms from various countries that can be used to identify features on planetary maps, sometimes with very different meanings.
The International Astronomical Union (IAU) is recognized as the global arbiter of all planetary and satellite nomenclature. Task groups for various planetary subdivisions were formed to oversee the assignment of names for newly identified features on any extraterrestrial object. When images are first obtained of the surface of a planet or other solar system object, a theme for naming features is chosen and a few of the most prominent features are named, usually by members of the appropriate IAU task group. Later, as better images and maps become available, additional features are named, usually at the request of individual investigators mapping or describing specific surface features. Names are considered “provisional” once approved by the appropriate task group, and the names only become official after being approved by the entire IAU assembly, representing scientists from all countries of the world. Many people do not realize that there is this well established procedure for applying names to planetary surfaces, one that makes the process a global effort and not the jurisdiction only of the space-faring nations. Along with specific names for individual features, the IAU has also recognized many terms for use in providing some broad classification of the feature type. We next provide a list of the most common of these descriptive terms, sanctioned by the IAU and developed over many years of planetary map-making. These lists are derived from a variety of published sources; see the reference section at the end of this glossary for citations of several key publications regarding planetary nomenclature.
Asteroid is a small body located in a heliocentric orbit that is usually located between the orbits of Mars and Jupiter (see asteroid belt). The diameter of asteroids range from hundreds meters to ~1000 km. At the present time, more than 20,000 asteroids have been discovered. Precise orbits are known for about 5000 asteroids.
Asteroid belt is a region of heliocentric space from 2.1 to 4.3 astronomical units that includes the majority of asteroids.
Asteroid family is a concentration of asteroids with similar orbital properties. Asteroids are thought to have a common origin; that is, they are remnants of objects that failed to accrete into a planet. More than fifty families represent about 40 % all asteroids. The largest family has 259 members. Quite often the mass of the largest member of a set is much greater of total mass of all remaining members of the family.
Comet is a small ice-rich body in heliocentric orbit with a diameter that ranges from hundreds of meters to several kilometers, orbiting the sun in nearly parabolic paths. When they approach close to the Sun, a comet forms a “tail” of gas and dust vaporized off the solid nucleus. Comets are subdivided into long-period comets and short-period comets, depending on the duration of their orbital period. The following basic elements refer to the structure of a comet: a nucleus (the solid central core), a photometric nucleus (the visible bright dusty region immediately surrounding the nucleus), a coma that makes the “head” of the comet, and a “tail” of gas and dust.
Cometary nucleus is a rigid body likely consisting of a conglomerate of refractory rigid particles (olivine, pyroxene, etc.) and “frozen” volatile components (ice, organic substances, hydrates etc.). The diameter ranges from 0.5 to 20 km. For example, the nucleus of comet Halley, measured by space vehicles, is characterized by low density (~0.6 g/cm3), a mass of ~3 X 1017 g, and three axial dimensions of 7.5 +/- 0.8 km, 8.2 +/- 0.8 km, and 16.0 +/- 1.0 km.
Comparative planetology is a direction of a science investigating small and planetary Solar system bodies, their structure, history of development and processes, which have resulted in current state and support their further development.
Deep space is all space outside the magnetosphere of the Earth. Sometimes this term is used for designation of all space outside of Earth’s orbit.
Extraterrestrial object is located off the Earth, and has a solid surface or separate segments of a rigid surface.
Families of comets is designated by aphelion distance of comet orbits that are near to the orbital distance of various gas-giant planets. Sets of planetary comets are known for Jupiter, Saturn, Uranus, and Neptune. The transition from one comet family into another is possibly due to gravitational disturbances during close encounters with planets.
Galilean satellites are the four largest satellites of Jupiter (Io, Europa, Ganymede and Callisto), discovered by Italian scientist Galileo Galilei in 1610.
Geomorphology is a science about the forms on the surface of a planetary and small Solar system bodies considering a classification, origin both development of the relief features and their relationship with geological structures.
Geologic time scale is sequence, built in the chronological order for events of a geological history of planetary bodies and intervals of time, appropriate to them. The geological time scale integrates two various types of scales: chronometric or geochronologic, based on units of duration (periods) and chronostratigraphic, which represents chronological sequence of rocks mountain.
Inferior planets The planets Mercury and Venus are inferior planets because their orbits are closer to the Sun than is Earth’s orbit.
Irregular satellite is a satellite with an eccentric (non-circular), often inclined orbit, which indicates that it was captured into its present orbit. Orbits of irregular satellites usually have the objects relatively far from their central planet. At Jupiter, the irregular satellites form two groups. The first (internal) group is within a distance of 160 RJ (radii of Jupiter) and is characterized by an eccentricity e > 0.15 and orbital inclination i > 28°. The second (external) group is outside a distance of 360 RJ, with e > 0.25 and i > 150°. Some satellites of Saturn (such as Phoebe) and one satellite of Neptune (Nereid) are also irregular satellites.
Leading hemisphere is the hemisphere that faces forward, into the direction of motion of a satellite that keeps the same face toward the planet. (to item 1
Minor planets. Another term used for asteroids.
Near Space (that is space near the Earth) is usually associated with the magnetosphere of the Earth. Sometimes it is understood to be all pf deep space within the limits of Earth’s orbit.
Outer planets (gas-giant planets) are Jupiter, Saturn, Uranus and Neptune. They differ from terrestrial planets by their larger sizes and lower mean densities, as well as chemical and internal structural differences. About 99.6 % of the total mass of all the planets is contained within the gas-giant planets. Principal components of the dense atmospheres of Jupiter and Saturn are hydrogen and helium. Uranus and Neptune contain mostly hydrogen, helium and methane. The gas-giant planets have numerous satellites. All of these planets are circled by rings that consist of small solid particles.
Planet is a celestial body orbiting around the Sun, held by the solar gravitational field and reflecting solar light. Today nine planets are known in the Solar System. Many planets, with the exceptions of Mercury and possibly Pluto, have a gaseous envelope or atmosphere. Also, most planets have satellites, except for Mercury and Venus. Based on the physical characteristics, chemical composition and internal structure, the planets are divided into two groups: terrestrial planets and gas-giant planets.
Planetary body is an object described by the approximately spherical form (shape) that it assumes under the hydrostatic force produced by gravity associated with its mass. The planets, large satellites of planets and the largest asteroids all can fall within a class of planetary bodies prescribed by a mostly spherical shape. Also sometimes called a planetoid.
Planetesimal is a hypothetical solid celestial body that accumulated during the last stages of accretion, as part of the formation of a larger planetary body.
Regular satellite is a satellite within a miniature “solar system” orbiting about the three largest gas-giant planets. They include the four Galilean satellites of Jupiter, eight satellites of Saturn, and five satellites of Uranus. Orbits of regular satellites, as a rule, are nearly circular and lie near the equator of their central planet. It is believed that the systems of regular satellites formed under processes similar to those that resulted in the formation of the Solar System as a whole.
Satellite is a body in orbit around another larger body (such as a planet or star).
Solar system describes all material substance and deep space included within the sphere of the gravitational attraction of the Sun. This includes the Sun, the planetary system, asteroids, comets, and all gas and dust that is gravitationally bound to the Sun. The effective edge of the solar system corresponds to distances from the Sun where the gravitational perturbations of passing stars are of comparable magnitude to the gravitational pull of the Sun itself.
Space is all space located beyond the Earth and its atmosphere or, more precisely, outside the ionosphere. Accordingly, the magnetosphere bounding the ionosphere is already part of deep space. Also applies to terms such as near space or deep space.
Stratigraphy is 1. Area of geology engaging problems of historical sequence of primary relationships and geographical distribution of formations composing planetary body crust and reflecting stages, its nature of development. 2. The description on bedding sequence of geological formations of that or other region.
Terminator The dividing line between the illuminated and the unilluminated part of the moon’s or a planet’s disk. (To item 1)
Trailing hemisphere The hemisphere that faces backwards, away from the direction of motion of a satellite that keeps the same face toward the planet. (To item 1)
Terrestrial planets are planets with the physical characteristics, chemical composition and internal structure similar to the Earth. Mercury, Venus, Earth and Mars belong to this category. The terrestrial planets have 0.4% of the total mass of all the planets in the Solar System. Some large satellites of planets are also similar to the characteristics of the terrestrial planets, and may be considered to be members of this group that are in orbit about a larger planet.
Cartographic materials for planetary cartography include maps such as general geographic, thematic, special, and topographic maps, and atlases such as photographic, specialized and complex (or integrated), globes, and different models of celestial bodies.
Cartographic organizations on planetary cartography are groups of experts engaged in extraterrestrial mapping, such as Working Groups and Commissions in international unions, and experts on national committees or budget organizations for separate countries (e.g., the Commission on Planetary Cartography in the ICA).
Cartographic sources for planetary cartography, these include materials from a space survey, materials from ground-based telescopic observations, and all graphic, digital and text data used for drawing and updating maps.
Cartometry (map measurements) in planetary cartography is a section of cartography of extraterrestrial objects that includes methods of measurement on maps of lengths, areas, angles, volumes, etc. Also can include calculation of the statistical distribution of separate relief features.
Extraterrestrial Cartography is mapping of all objects located off the Earth (e.g., celestial star charts, maps of sun spots, etc.).
History of planetary cartography investigates problems connected to the origin and evolution of the mapping process for solar system bodies.
Nomenclature on planetary cartography is a system of names for features on planetary surfaces (including relief features).
Planetary Cartography includes all cartographic materials produced for objects with solid surfaces external to the Earth. This can include any spatially mapped characteristic (e.g., topography, geology, and geophysical properties) for extraterrestrial surfaces. Also can be referred to as the Cartography of Extraterrestrial Objects (CEO).
Transcription in planetary cartography is a system of special phonetic sounds used to aid the correct pronunciation of the sounds associated with various names.
Albedo map shows the measured difference in surface reflectivity from the surface of celestial body.
Atlas is a special collection of images of a celestial body surface. The images may be from either ground-based or spacecraft sources. Usually a single scale or set of scales is used throughout the atlas. Atlases can have specific themes (e.g., photographic, specialized to certain problems, thematic, etc.).
Complex (integrated) atlas of groups of celestial bodies is a systematic collection of maps of a group of celestial bodies (e.g., the terrestrial planets, satellites of the gas-giant planets, etc.), giving a capability for the analysis of the collected information through comparative planetology.
Geochemical map shows the distribution of chemical elements or minerals on the surface of a celestial body.
Geologic map is a graphic representation generalizing the geological history of the area covered by the map. It includes information on the structure, distribution, age, and genetic type of rocks on the surface of the celestial body.
Geologic/morphologic map shows the spatial distribution of geologic, geomorphologic, and tectonic features on a celestial body.
Geomorphic map is a graphic representation of the distribution of surface morphological types portrayed in the landforms on a planetary body. Geomorphic maps do not attempt to infer the geologic history of the rocks themselves, but rather the processes that have generated the present surface features.
Geophysical map shows a variety of geophysical information in a spatial representation (such as gravimetric, seismic, and magnetic anomaly maps).
Globe is cartographic representation of the surface of a planetary body on a three-dimensional shape (which can be spherical or non-spherical, such as a tri-axial ellipsoid), preserving the geometric similarity of both locations and outlines features. Globes of spherical planets and irregular objects (e.g., the Martian moon Phobos, the asteroid Eros) have been produced from imaging and remote sensing data obtained from a variety of sources.
Hypsometric map shows the macro-relief features on a planetary surface (for maps produced in Russia). The relief is represented by means of contours or isolines (to show areas at the same relative elevation), and color-coded contour intervals. In other countries, this term can also describe the distribution of elevations on the extraterrestrial object.
Landing site map in planetary cartography is a graphic representation of the region surrounding the site where a spacecraft came to rest on a planetary surface (generally shown at large scale).
Map in planetary cartography is a generalized image of the surface of an extraterrestrial solid body (excluding the Earth), that indicates the location of objects projected mathematically according to the adopted coordinate system used for the projection. Symbols can represent any subject, phenomena or process chosen by the cartographer to be illustrated on the map (a legend defining all symbols should be included to aid the map user). Maps of extraterrestrial territories represent all solar system bodies, with the exception of the Earth; they can be portrayed in a variety of forms, such as electronic (e.g., digital), conventional (printed), multilingual, orthophoto, drawing (e.g., shaded relief), outline, topographic (contoured), and thematic.
Outline map in planetary cartography is a map representing relief with the help of outlines and special symbols. These maps are used as base-maps for thematic and schematic mapping, which allows the user to link visually a represented attribute with a relief feature on the surface.
Physical properties map is a maps of various measured attributes of the extraterrestrial surface, such as albedo (see albedo, in this section), thermal anomalies (e.g., the distribution of hotspots on the Earth-facing hemisphere of the Moon), and polarimetric measurements.
Synoptic map in planetary cartography is a graphic representation of attributes (e.g., pressure, temperature, etc.) that describe the weather above a planetary surface (e.g., a map of weather on Mars).
Tectonic map in planetary cartography is a graphic representation of structural elements related to the tectonic history of the upper crust of a planetary body. The different structural areas and their separate elements (e.g., faults and folds) are shown by various symbols; when combined with a geologic map, data regarding the age and type of rocks comprising the structural elements are given, along with their development in time.
Thematic map in planetary cartography is a map showing the spatial representation of physical properties for a planetary surface (e.g., hypsometric, geophysical, geologic-morphologic, and geochemical maps).
Terrain map in planetary cartography is a graphic representation of the distribution of boundaries between mapped regions on the planetary body, showing the presence or absence of characteristic details of a surface (e.g., impact craters, hills, faults, lava flows, aeolian cover, etc). Such maps are usually produced by data obtained by remote sensing. See also geologic/morphologic map, photogeologic map.
Extraterrestrial mapping is the process of the creation of cartographic products of all objects beyond the surface of the Earth. This includes mapping of planets, moons, asteroids, and small or irregularly shaped objects (e.g., a comet nucleus).
Meteorology mapping is weather maps (e.g., those related to climate) of solar system bodies involves the creation of thematic maps that describe various climatic conditions (e.g., temperature, pressure, cloud conditions at a given time) on these celestial bodies.
Complex (integrated) mapping for solar system bodies, this involves the creation of versatile cartographic products that represent the various characteristics of these bodies, which can be used in comparative planetology.
Cartography for extraterrestrial territories, this includes the development of special projections for the maps, with allowance for selecting the best surface on which to represent these objects (e.g., triaxial ellipsoid, oblate spheroid, etc.).
Albedo Features = albedo features.
Catena = chain. Cavus = hollow. Chaos = canyon. Collis = hill.
Crater = crater. Chasma = canyon. Corona = ring.
Dorsum = ridge.
Facula = light spot. Farrum = pancake like structure. Flexus = bend, twist, winding. Fluctus = flow. Fossa = furrow.
Labes = landslide. Labyrinthus = maze. Lacus = lake. Linea = line. Large Ring Feature only in English.
Macula = dark spot. Mare = sea. Mons = mountain. Mensa = mesa.
Oceanus = ocean.
Palus = swamp, marsh. Patera = patera. Planitia = plain. Planum = plateau.
Plume = Eruptive Center both in English. Promontorium = cape.
Regio = region. Rupes = rupes.
Scopulus = scarp. Sinus = bay. Sulcus = groove.
Terra = terra. Tessera = tile. Tholus = dome.
Unda = wave.
Phobos – Crater, Dorsum.
Deimos – Crater.
Amalthea – Crater, Facula.
Callisto – Crater, Catena, Large Ring Feature.
Europa – Chaos, Crater, Large Ring Feature, Flexus.
Io – Catena, Eruptive Center, Fluctus, Mensa, Mons, Patera, Planum, Tholus.
Ganymede – Catena, Crater, Facula, Fossa, Regio, Sulcus.
Thebe – Crater.
Enimetius – Crater.
Janus – Crater.
Hyperion – Crater, Dorsum.
Mimas – Crater, Chasma.
Enceladus – Fossa, Planitia, Sulcus.
Tethus – Crater, Chasma.
Dione – Crater, Chasma, Linea.
Rhea – Crater, Chasma.
Iapetus – Crater, Regio, Terra.
Phoebe – Regio.
Ariel – Crater, Chasma, Vallis.
Umbriel – Crater.
Titania – Crater, Chasma, Rupes.
Oberon – Crater, Chasma.
Miranda – Crater, Corona, Regio, Rupes, Sulcus.
Proteus – Crater.
Triton – Crater, Catena, Cavus, Dorsum Fossa, Macula, Patera, Planitia, Planum, Plume, Regio, Sulcus.
Eros – Crater, Dorsum, Regio.
Ida – Crater,Dorsum, Regio.
Gaspra – Crater, Regio.
Dactil – Crater.
Latin singular (Latin plural) – description
Albedo Feature (Albedo Features) is some area characterized by reflective ability of the surface albedo feature.
A dark or light marking on the surface of an object that might not be a geological or topographical feature.
Catena (catenae) – a crater chain, or a string of closely spaced depressions.
Catena (Catenae) is a line-up or line of craters (chain of craters).
catena – A chain of craters.
Cavus (cavi) – an irregular, steep-sided depression that apparently is not of impact origin.
Cavus (Cavi) is a steep slope depression with irregular form in the plan. It is usually located by groups (in polar areas)
cavus – A hollows, irregular depression.
Chaos – a discreet region of disrupted or broken terrain.
Chaos (Chaos) is a characteristic region of a destruction relief
chaos – A distinctive area of broken terrain.
Chasma (chasmata) – a steep-walled trough or large canyon
Chasma (Chasmata) is a steep slope linear depression. Canyon ( canyons) in English chasma A canyon
Collis (colles) – a small hill, usually round in the plan form.
Collis (Colles ) is a small height form usually round in the plan and formed accumulations. Hill (hills) in English
colles – A small hill or knob.
Corona (coronae) – large circular feature enclosed by a ring of concentric ridges and furrows.
Corona (Coronae) is ring-type structure of diameter approximately from 150 up to 600 kms formed by a system of concentric ridges and furrows and having in the plan the form of a circle or an oval. It is supposed, that their formation is connected with “bleed” dome like raisings above hotspots. For the first time the rings of this kind are chosen and circumscribed on Venus, where they are widely widespread. The rings of other genesis are known on satellites of Saturn, Jupiter. A synonym is an ovoid. Ring in English.
corona – The upper level of the solar atmosphere, characterized by low densities and high temperatures (> 1.0E+06 K); it is not visible from the Earth except during a total eclipse of the sun or by use of special telescopes called coronagraphs. 2) An ovoid-shaped feature.
Crater (craters) – bowl-like to flat-floored depression, usually surrounded by steep walls.
Crater is a bowl like depression on a surface of a planetary or small of a Solar system body. Depending on a way of formation they can be impact, explosive, volcanic etc
crater 1) A depression formed by the impact of a meteorite. 2) A depression around the orifice of a volcano.
Dorsum (dorsa) – a topographic ridge or other elongated, raised structure.
Dorsum (Dorsa) is a linear height with irregular form in the plan . Ridge (ridges) in English.
Dorsum is a positive linear extended form of a relief (elevation) on a surface of a planetary Solar system body . Dorsacan be of the various sizes and various structure (steep slopes and flat slopes), extended or short etc. Ridge (ridges in English).
dorsum – A ridge
Facula is a bright region.
Flexus – a very low curvilinear ridge consisting from arcuate bands.
Flexus (flexus) is
flexus – A cuspate linear feature
Fluctus (flucti) – a complex association of digitate (flow-like) features emanating from a common source location or feature.
fluctus – A flow terrain
Fossa (fossae) – a long, narrow, shallow depression or a narrow, linear trench.
Fossa (Fossae) is a linear downturn on a surface of a small or planetary Solar system body. Furrows can be resulted by tectonic or impact deformations or in an outcome of deleting of a material of rocks mountain under effect of exsogenic processes (for example, furrows of blowing out in yardangs). Furrow (furrows) in English.
Fossa is a long, narrow, superficial depression. They are usually located by groups. They can be rectilinear or curved but not twisting. Furrow (furrows) in English.
fossa – A long, narrow, shallow depression.
labes – A landslide.
Large Ring Feature
Labyrinthus (labyrinthi) – a complex maze of intersected valleys or canyons.
Labyrinthus ( Labyrinthi) is a complex of intersected valleys (canyons). Maze ( mazes) in English.
labyrinthus – An intersecting valley complex.
Lacus (laci) – a low plain smaller than a mare, originally thought to be a lake.
Lacus (laci) -is a low plain smaller than a mare, originally thought to be a lake. Lake in English.
lacus – A lake.
Linea (lineae) – a linear feature; they can be dark or bright relative to their surroundings, and either curved or straight
Linea (lineae) – dark or light linear feature, which can be curved or straight.
Linea (Lineae) is a dark or light oblong relief feature, they can be curve or direct. Line (lines) in English.
linea – An elongate marking.
Macula (maculae) – a dark, irregular spot.
Macula (Maculae) is a dark spot, they can have an irregular form. Spot (spots) in English.
Mare (maria) is broad low plains surrounded by basin-forming mountains, originally thought to be a sea. Sea in English.
Mare (Maria) – broad low plains surrounded by basin-forming mountains, originally thought to be a sea.
Mare is a large low lands. Sea in English.
Mare – Latin word for “sea.” Galileo thought the dark featureless areas on the Moon were bodies of water, even though the Moon is essentially devoid of liquid water. The term is still applied to the basalt-filled impact basins common on the face of the Moon visible from Earth.
Mensa (mensae) – a flat-topped, steep-sided elevated feature.
Mensa (Mensae) is a height with a table top and break or terrace edges.
mensa – A mesa, flat-topped elevation.
Mons (montes) – a mountain.
Mons (Montes ) is a large height of relief (Mons) or chain of heights (Montes). Mountain ( mountains) in English.
mons – A mountain
Oceanus – a very large low plain (Oceanus Procellarum), originally thought to be an ocean.
Oceanus is a very large low plain, originally thought to be an ocean. Ocean in English.
oceanus – An ocean.
Ovoid (look at corona).
ovoid – Shaped like an egg.
Palus is some part of low land. Marsh in English.
palus – A swamp.
Patera (paterae) – a shallow crater with scalloped, complex walls or edges.
Patera (Paterae) is a crater of the irregular form or complex crater with toothed edges.
Patera is crater of any genesis with irregular or toothed edges. Patera is sometimes named a volcanic muzzle, enclosed with flows of the irregular form.
patera – Shallow crater; scalloped, complex edge.
Planitia – a low plain, or a large level expanse of lowlands.
Planitia (Planitiae) is an equal low area. Flatness (flatnesses) in English.
planitia – Broad plains that occupy lowlands on planetary surfaces.
Planum – a large elevated plateau or high plain.
Planum (Plana ) is an equal raised area. Plateau ( plateaus) in English.
planum – A plateau or high plain.
Plume, see Eruptive Center
Promontorium – part of the lunar highlands extending into an adjacent mare, originally thought to be a cape or promontory within a sea.
Promontorium is a part of the lunar highlands extending into an adjacent mare, originally thought to be a cape or promontory within a sea. A cape in English.
promontorium – A cape.
Regio (regiones) – a large region distinguished from nearby areas by color or albedo.
Regio (Regiones) is a large region distinguished from nearby ones on brightness or colour. Area ( areas) in English.
regio – Region.
Rupes (rupes) – one-sided terrace or break in the surface.
Rupes (Rupes) is a terrace or break relief feature.
rupes – The term applied to scarps on planetary surfaces; many scarps are thought to be the surface expression of faults within the crust of the planetary object.
Scopulus (scopuli) – a terrace or break in the surface, with serrated or very irregular plan form.
Scopulus (Scopuli ) is a complex terrace or break relief feature with toothed or very.
scopulus – A lobate or irregular scarp irregular in the plan form.
Sinus – a low plain only partially surrounded by mountains, originally thought to be a bay on a larger sea.
Sinus is a low plain only partially surrounded by mountains, originally thought to be a bay on a larger sea.
Sinus is a part of a very large low land. Bay in English.
Sinus – A bay.
Sulcus (sulci) – a complex region with subparallel furrows and ridges.
Sulcus (Sulci ) is a complex region of subparallel furrows and ridges.
sulcus– Subparallel furrows and ridges.
Terra (Terrae ) is a height with the crossed relief.
terra – An extensive land mass.
Terra (terrae) – elevated area with the complex relief (e.g., highlands).
Tessera (tesserae) – an elevated area of complex relief, crossed by lineations in two or more directions; having the appearance of a parquet tile pattern or drawing.
Tessera is type of district on Venus describing areas with development of heavy deformations, widespread on the significant area (from 10 in 5grade up to 10 in 6grade km). The structural drawing of its surface is formed by systems which are represented by intersected, less often sub-parallel ridges and dividing by their valleys. The characteristic distance between crests of adjacent ridges makes on the average 10-12 km. Tesserae represent, as a rule, territories elevated rather lava flatness, often limited on edges by shelf. They have not morphological analogs on the Earth.
tessera – A tile; polygonal ground.
Tholus (tholi) – a small domed hill.
Tholus (Tholi) is a separate small dome like mountain or hill. Dome (domes) in English.
tholus– A small domical mountain or hill.
Unda (Undae) is hard (solid) wave in relief.
Vallis (valles) – a valley.
Vallis (Valles ) is twisting hollow, it has frequently inflow. Valley (valleys) in English.
vallis– A sinuous valley.
Vastitas – an extensive flat plain (in the northern hemisphere of Mars).
Vastitas (Vastitates) is a flatness very extensive on the area. Great plain (great flatnesses) in English.
Vastitas – A widespread lowland.
Arachnoid – a radial-circular structure with a “spider-like” pattern, generally from 70 to 250 km in diameter. They usually have a central locus, enclosed by one to three broad concentric shafts and narrow radial ridges. Arachnoids on Venus are interpreted to have an endogenous origin. A variation on the more common corona features on Venus.
Astrobleme – geological structure on the Earth generated by a hypervelocity impact (e.g., see crater).
Basin – a very large impact structure with a system of concentric walls. They generally form the topographic lows on the surfaces of many solar system bodies.
Bajada – a broad extended alluvial slope, or a gently inclined surface. Formed by extended periods of sheetwash erosion in an arid environment.
Bench – a terrace or one-sided break in a planetary surface.
Block – rock debris or breccia accumulation of rock fragments, generally >1 m in size.
Boulder – rock debris or breccia accumulation of rock fragments, generally >10 cm to 1 m in size. In the literature the term is often used for non-rounded fragments, all of similar size.
Caldera – a circular depression with steep walls and relatively level floor, reaching dimensions greater than many tens of kilometers. Usually associated with the collapse of the roof above a volcano magma chamber. The largest volcanic calderas (diameter more than 100 km) are known on Venus (e.g., Mockoshi Mons) and on Mars (e.g., Olympus Mons, etc.).
Central volcano – a volcano at which eruptions form an intermixed accumulation of lava and ash debris around a central vent. Also known as composite volcanoes.
Cliff – a rocky shelf or bench. Cliffs occur on steep to vertical slopes, or even above overhangs. They usually occur in mountainous areas, but also are by the shores of lakes or rivers. Such slopes, as a rule, grow out of erosion or faulting processes.
Comparative planetology – the scientific investigation of solar system bodies, their structure, history of development, and the processes that have resulted in their current surface conditions.
Corona – a circular structure with a diameter of from 150 to 600 km, formed by a system of concentric ridges and furrows and having a plan form of a circle or oval. Their formation is believed to be related to plume upwelling above a hotspot. Originally identified on Venus, where they are quite common, these structures may also exist on other planetary surfaces.
Crater – a bowl-shaped depression on the surface of a planetary body. Craters occur on all sizes of objects, from individual rocks to planets. Craters are most often the result of a hypervolocity impact, but they may also be the product of a volcanic explosion or a collapse.
Crater rim – circular elevated terrain surrounding a crater, with internal slopes in fresh impact craters that are much steeper than the external slopes.
Depression – any portion of the surface of a solar system body that is lower in elevation than its surroundings, regardless of origin. The term has a wide potential use, and it may be used instead of the more specific terms such as basin, crater, furrow, etc.
Dune – a low hill or ridge, which may be asymmetric with a shallower slope on the upwind side, comprised of granular wind-blown, sand-sized material (or possibly of volcanic ash). Active dunes are capable of moving along the prevailing direction of the wind, preserving its characteristic form during transport.
Fault – a discontinuity in rock or sediment, along which noticeable displacement has occurred. Depending on depth, these breaks are usually subdivided between steep near-surface (crustal) discontinuities, and deep-seated (sub-crustal) breaks. Upon expansion, the breaks are subdivided into local, regional and trans-regional scales. Faults also can be subdivided based on the duration of development, whether inherited from a previous zone of weakness, newly formed, or reactivated.
Fissure volcano – a volcano formed along a crack or linear vent. The eruption can occur all along the associated fissure, or only along separate segments of the fissure. These eruptions usually are associated with extensive flows of lava. This is a common form of eruption for fluid basaltic lavas on the terrestrial planets.
Furrow – a linear depression in the surface of a solar system body. Furrows can be the result of tectonic or impact deformation, or as a result of exogenic processes (e.g., erosional furrows in yardangs).
Graben – a tectonic linear depression in the surface of a planetary body, usually formed by paired faults with a lowered floor between the faults. Fault length along a graben is always significantly greater than the width of the structure.
Geomorphology – the science of describing the shape and origin of landforms. It can involve quantitative and qualitative descriptions and classifications, as well as various interpretations of the possible origins of the landform.
Geologic time scale – the chronological sequence for events, and their associated time scales, for the geological history of planetary objects. Geologic time involves two types of time scales: chronometric or geochronologic, based on measured intervals of time (periods) derived from laboratory analysis of rock samples, and chronostratigraphic, which represents chronological sequence of rock emplacement.
Interdune valley – a hollow between adjacent sand dunes or sand ridges.
Lava flow – rock formed by solidification of molten lava which has erupted from one or more vents in the surface. A lava flow is characterized by a digitate or lobate planform that extends in the direction of flow. The shape and thickness of a lava flow is affected by the type of eruptive vent (e.g., point source or linear vent), volume and effusion rate of the erupted lava, the material structure and chemistry of the lava, and the topographic relief over which it flowed.
Lineament – any linear formation on the surface of a solar system object. Sometimes lineaments represent any linear feature of undetermined origin observed on images, as opposed to precise feature terms (e.g., ridges, valleys, etc).
Lunar highlands – relatively high albedo, elevated, heavily cratered terrain on the Moon. The lunar highlands comprise most of the lunar far side (the side never visible from Earth), and they represent >80 % of the total surface area of the Moon.
Lunar Maria – relatively low albedo, low-lying, more lightly cratered terrain on the Moon. The Maria consist of lavas that have flooded the floors of the largest impact basins on the Moon. They are mainly found on the Earth-facing side of the Moon, representing about 1/3 of the surface visible from Earth, but Maria are relatively rare on the lunar far side (the side never visible from Earth).
Meander – the sinuous path of a river on a shallow-sloped flood plain, consisting of the loops and turns produced by the unconstrained wandering of the river channel.
Mesa – an isolated, flat-topped elevated region surrounded by abrupt erosive cliffs.
Microcrater – small impact crater, ranging from micrometers to several centimeters in diameter. Microcraters are abundant on the rocks and surface of any airless body.
Normal fault – a break in the crust of a rocky object resulting from extensional forces so that the rocks above the fault plane have moved down relative to the rocks below the fault plane.
Ovoid – see corona (and section 4.2.3).
Peneplain – a relatively flat erosion surface that approaches being a perfect plain as a result of very long periods of erosion with little tectonic deformation.
Ridge – a positive-relief linear feature on any solid surface. Ridges can be of various sizes and origins.
Rift – a break in the surface of a planetary body of regional or global extent. Rifts are considerably larger structures than graben. The formation of rifts is characteristic of large planetary bodies displaying considerable endogenic activity.
Rille – an extended crack, up to several hundred km in length, generally from 2 to 5 km in width, and with depths up to 0,5 km. Rilles are common features on the surface of the Moon, and are present on several of the terrestrial planets. They can have irregular twisting planform, or be rather straight or rectilinear.
Scarp – any topographic break with one side higher than the other (equivalent to cliff).
Shield volcano – a volcanic construction of a central type formed by repeated effusion of very fluid (usually basaltic) lava. The shield is characterized by a shallow flank, the steepness of which can vary from a high of 7° to 8°, to a low of >1°, but with typical values of ~5°. There often are one or more caldera craters near the summit, like broad saucer-shaped cavities with steep walls. One of the largest shield volcanoes in the solar system is Olympus on Mars, with a diameter greater than 500 km and total relief of 25 km.
Stratigraphy – the science of the description, correlation, and classification of strata in sedimentary rocks, including the interpretation of the depositional environments of those strata. In planetary mapping, volcanic and metamorphic rocks are also included in a relative stratigraphic interpretation of the sequence of emplacement of all mapped rocks.
Terrace – any narrow, nearly horizontal surface, usually with a distinct cliff or termination on one or more sides. Terraces are sometimes subdivided depending on their genesis and structure.
Wrinkle ridge – an extended system of gently sloping, often sinuous ridges, with lengths exceeding tens to hundreds of km, widths of several to tens of km, and elevations up to several hundred meters. Wrinkle ridges are usually found on the volcanic plains, but their origin has been attributed to both tectonic and volcanic processes.
Yardang – an elongated form produced by prolonged wind erosion. On Earth, yardangs they are observed to have relief of up to hundreds of meters and lengths of up to many kilometers. They are formed by wind erosion on indurated rocks capable of holding steep erosional walls, and they are oriented parallel to the direction of prevailing winds.
Albedo is a measure of surface reflectance, usually expressed as a number between 0 (no reflection) and 1 (complete reflection of all incident energy). Albedo can vary depending on the wavelength of incident radiation. Specific constraints on the way the reflected energy is measured can lead to terms such as geometric and spherical albedo, both of which are widely used in planetary photometry.
Geoid is the height of a natural surface can be expressed as being above or below a mathematical surface representing a gravitational equipotential surface, or geoid. The geoid of Earth can be expressed in the shape of a sphere of revolution.
Height of the geoid is size of deviation of a surface of a geoid from a spheroid of rotation.
Hot spot Center of persistent volcanism, thought to be the surface expression of a rising hot plume in Earth’s mantle
Geoid is such a surface of equal values of a gravity potential on the Earth conterminous to a undisturbed surface of World ocean and continued under the oceans.
Isostasy is The mechanism whereby areas of the crust rise or subside until the mass of their topography is buoyantly supported or compensated by the thickness of crust below, which “floats” on the denser mantle. Isostatic gravity anomalies are derived from the assumption that the gravitational effect of the mass associated with the surface topography is approximately compensated by a deficit of either the density or the subsurface thickness of the crustal material.
Isostatic anomaly is anomaly of gravity calculated proceeding from the supposition, that gravitational effect of weights located above of levels on a surface of a planetary body (on the Earth sea level), is approximately compensated by a deficit on density of a material under these weights.
Leading hemisphere The hemisphere that faces forward, into the direction of motion of a satellite that keeps the same face toward the planet. (To item 1)
Mascon is positive gravitational anomaly on Earth’s Moon, spatially associated with the largest circular mare. Mascons are observable when an orbiting spacecraft’s speed in orbit around the Moon is altered by the increased gravitational attraction produced by a buried concentration of mass within a mare area. First described after monitoring the orbits of the Lunar Orbiter spacecraft in the 1960s, the term “mascon” is the concatenation of the two English words “mass concentration” (e.g., an enhanced concentration of mass relative to the surrounding lunar terrain).
Mascons are positive gravitational anomalies on the Moon spatially connected to the largest seas of circular outlines. ?ascons are chosen on observations over speed of motion on orbit of artificial lunar satellites of a series “Lunar Orbiter”. A term “mascon” is an English abbreviation from mass concentration ( concentration of weights).
Polarimetry (polarimetric method of determination of an albedo) is based on relation of an albedo to change of polarization of ambient light with a phase angle (a).
Polarization A special property of light; light has three properties, brightness, colour and polarization.
Regolith The layer of rocky debris and dust made by meteoritic impact that forms the uppermost surface of planets, satellites and asteroids.
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