Classical albedo features on Mars
The classical albedo features of Mars are the light and dark features that can be seen on the planet Mars through an Earth-based telescope. Before the age of space probes, several astronomers created maps of Mars on which they gave names to the features they could see. The most popular system of nomenclature was devised by Giovanni Schiaparelli, who used names from classical antiquity. Today, the improved understanding of Mars enabled by space probes has rendered many of the classical names obsolete for the purposes of cartography; however, some of the old names are still used to describe geographical features on the planet.
History
Observing albedo features
Early telescopic astronomers, observing Mars from a great distance through primitive instruments, were limited to studying albedo contrasts on the surface of the planet. These lighter and darker patches rarely correspond to topographic features and in many cases obscure them. The origins of the albedo contrasts were a mystery. The lighter patches at the poles were correctly believed to be a frozen substance, either water or carbon dioxide, but the nature of the dark patches seen against the general reddish tint of Mars was uncertain for centuries. When Giovanni Schiaparelli began observing Mars in 1877, he believed that the darker features were seas, lakes, and swamps and named them accordingly in Latin. Within a few decades, however, most astronomers came to agree that Mars lacks large bodies of surface water. The dark features were then thought by some to be indications of Martian vegetation, since they changed shape and intensity over the course of the Martian year. They are now known to be areas where the wind has swept away the paler dust, exposing a darker surface, often basaltic rock; so their borders change in response to windstorms on the Martian surface that move the dust around, widening or narrowing the features.The dust-storms themselves also appear as light patches, can cover vast areas and sometimes last for many weeks; when Mariner 9 arrived in Martian orbit in November 1971 the entire planet was covered by a single enormous dust-storm, with only the peaks of the four or five highest mountains showing above it. This variability may explain many of the differences between telescopic observations over the years.
Early non-classical names
The first map of Martian albedo features was published in 1840 by Johann Heinrich Mädler and Wilhelm Beer, but they simply labelled the features a, b, c... without giving them names. Over the next two decades the most prominent features picked up various informal names but there was no overall system.The first astronomer to name Martian albedo features systematically was Richard A. Proctor, who in 1867 created a map in which several features were given the names of astronomers who had been involved in mapping Mars. In some cases, the same names were used for multiple features. Proctor's names remained in use for several decades, notably in several early maps drawn by Camille Flammarion in 1876 and Nathaniel Green in 1877.
Schiaparelli's classical names
However, within a few decades Proctor's names were superseded by a new scheme devised by Giovanni Schiaparelli, whose observations differed from Proctor's, and who used this difference to justify drawing up an entirely new system of nomenclature. Schiaparelli was an expert on ancient astronomy and geography, and used Latin names, drawn from the myths, history and geography of classical antiquity; dark features were named after ancient seas and rivers, light areas after islands and legendary lands.When E. M. Antoniadi took over as the leading telescopic observer of Mars in the early 20th century, he followed Schiaparelli's names rather than Proctor's, and the Proctorian names quickly became obsolete. In his encyclopedic work La Planète Mars Antoniadi used all Schiaparelli's names and added more of his own from the same classical sources. However, there was still no 'official' system of names for Martian features.
In 1958, the International Astronomical Union set up an ad hoc committee under Audouin Dollfus, which settled on a list of 128 officially recognised albedo features. Of these, 105 came from Schiaparelli, 2 from Flammarion, 2 from Percival Lowell, and 16 from Antoniadi, with an additional 3 from the committee itself. This involved a considerable amount of pruning; Antoniadi's La Planète Mars had mentioned 558 named features.
The pictures returned by interplanetary spacecraft, notably the observations made from Martian orbit by Mariner 9 over the course of 1972, have revolutionized the scientific understanding of Mars, and some of the classical albedo features have become obsolete as they do not correspond clearly with the detailed images provided by the spacecraft. However, many of the names used for topographic features on Mars are still based on the classical nomenclature for the feature's location; for instance, the albedo feature 'Ascraeus Lacus' provides the basis of the name of the volcano Ascraeus Mons in roughly the same position.
In addition, since most Earth-based amateur telescopes are not powerful enough to resolve the topographic surface features of Mars, amateur astronomers still use many of the old feature-names to orient themselves and record their observations.
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Common feature names
Several Latin words involved here are common nouns. These are generally, but not always, second in the name, but are usually ignored in alphabetizing below:- Campi - fields
- Cherso - peninsula
- Cornu - horn, peninsula
- Depressio - lowland
- Fastigium - summit
- Fons – fountain
- Fretum – strait
- Insula – island
- Lacus - lake
- Lucus - grove
- Mare – sea
- Nix – snow
- Palus - marsh
- Pons – bridge
- Promontorium – cape
- Regio - region
- Silva - wood
- Sinus – bay
List of albedo features
A
| Name | Meaning | Modern name | |
| Abalos | A no-longer existent island in the North Sea, east of Heligoland | Abalos Colles, Abalos Mensa, Abalos Scopuli, Abalos Undae | |
| Achæorum Portus | "Harbor of the Achaeans" | Obsolete | |
| Acherusia Palus | "Marsh of Acherusia", named after the legendary swamps in Greek mythology | Obsolete | |
| Achillis Pons | "Bridge of Achilles" | Obsolete | |
| Mare Acidalium | "Sea of Acidalia", named for the fountain Acidalia where the Graces bathed | Acidalia Colles, Acidalia Mensa, Acidalia Planitia | |
| Æolis | a modification of Aeolia, the name of the floating western island of Aiolos, the ruler of the winds | Aeolis Mensae, Aeolis Planum | |
| Aëria | From a poetic name for Egypt | Aeria, IAU recognized albedo feature | |
| Ætheria | – the land of the living, as referred to in Virgil's Aeneid | Aetheria, IAU recognized albedo feature | |
| Æthiopis | Land of the Ethiopians | Aethiopis, IAU recognized albedo feature | |
| Aganippe Fons | "Aganippe's Fountain", legendary home of a Greek naiad | Aganippe Fossa | |
| Alcyonia | Land of kingfishers. | Obsolete | |
| Amazonis | "Land of the Amazon", legendary warrior women | Amazonis Mensa, Amazonis Planitia, Amazonis Sulci | |
| Amenthes | Alternate name for Duat, the Egyptian land of the dead | Amenthes Cavi, Amenthes Fossae, Amenthes Planum, Amenthes Rupes | |
| Ammonium | Ancient name for the Siwa Oasis | Obsolete | |
| Mare Amphitrites | "Sea of Amphitrite", a Greek sea-goddess | Amphitrites Patera | |
| Lucus Angitiæ | "Grove of Angitia", named after the snake goddess | Obsolete | |
| Depressiones Aoniæ | "Lowlands of the Muses", who came from Helicon in Aonia | Obsolete | |
| Aonius Sinus | "Bay of the Muses" | Aonia Mons, Aonia Planum, Aonia Terra, Aonia Tholus | |
| Aponi Fons | Roman name for the Bagni d'Abano, warm-water baths near Padua | Obsolete | |
| Aquæ Apollinares | "Apollo's Waters"; Roman name for the Bagni di Stigliano baths in Canale Monterano, Tuscany | Obsolete | |
| Aquæ Calidæ | "Hot spring" | Obsolete | |
| Aquarii Depressio | "Lowland of Aquarius" | Obsolete | |
| Arabia | Arabian peninsula | Arabia Terra | |
| Arachoti Fons | "Fountain of Arachotus", a river in Afghanistan | Obsolete | |
| Aram | Aram, Biblical land of the Aramaeans | Aram Chaos | |
| Arcadia | From Arcadia, a region of the central Peloponnesus | Arcadia Chaos, Arcadia Dorsa, Arcadia Planitia | |
| Arduenna | Latin names for the Ardennes forests | Obsolete | |
| Arethusa Fons | "Arethusa's Fountain", after the Greek nymph | Obsolete | |
| Argyre I | One of a pair of legendary islands, Chryse and Argyre, located in the Indian Ocean and said to be made of gold and silver | Argyre Cavi, Argyre Planitia, Argyre Rupes, Argyre quadrangle | |
| Argyre II | "Second Silver Land" | Obsolete | |
| Argyroporos | "Silver Strait" | Obsolete | |
| Ariadnes Depressio | "Lowland of Ariadne", a Greek heroine | Ariadnes Colles | |
| Aromatum Promontorium | "Cape of Fragrant Spices" | Aromatum Chaos | |
| Arsia Silva | Arsia Silva, forest northwest of Rome where the Tarquinii were defeated | Arsia Chasmata, Arsia Mons, Arsia Sulci | |
| Arsinoës Depressio | Lowland of Arsinoë, the name of various Greek and Egyptian figures | Arsinoes Chaos | |
| Artynia Fons | "Artynia's Fountain", referring to Lake Artynia in Asia Minor | Artynia Catena | |
| Aryn Promontorium | "Cape of Aryn" | Obsolete | |
| Fastigium Aryn | "Summit of Aryn" | Obsolete | |
| Ascræus Lacus | "Ascraeus Lake", a poetic paraphase of "ian" or "rural" | Ascraeus Chasmata, Ascraeus Mons, Ascraeus Sulci | |
| Astræ Lacus | "Lake of the Astra", Greek star-gods | Obsolete | |
| Atalantes Depressio | Lowland of Atalanta, Greek heroine | Obsolete | |
| Nix Atlantica | "Snows of Atlas", a Titan in Greek mythology | Obsolete | |
| Atlantidum Sinus | "Bay of the Atlantises" | Obsolete | |
| Atlantis I | "First Atlantis", mythical drowned land | Atlantis Chaos | |
| Atlantis II | "Second Atlantis" | Atlantis Chaos | |
| Augila | Awjila, a city in Cyrenaica | Obsolete | |
| Aurea Cherso | "Golden Peninsula", ancient name for the Malay Peninsula | Obsolete | |
| Aureum Cornu | "Golden Horn", inlet dividing Constantinople | Aureum Chaos | |
| Auroræ Sinus | "Bay of the Dawn" | Aurorae Planum, Aurorae Chaos | |
| Ausonia | From a poetic name for Italy | Ausonia Cavus, Ausonia Mensa, Ausonia Montes | |
| Mare Australe | "Southern Sea" | Chasma Australe, Australe Lingula, Australe Mensa, Australe Montes, Planum Australe, Australe Scopuli, Australe Sulci, Mare Australe quadrangle |
B-E
| Name | Meaning | Modern name | |
| Baltia | From a name for the regions near the Baltic Sea | Baltia, IAU recognized albedo feature | |
| Bandusiæ Fons | "Fountain of Bandusia", title of a poem by Horace | Obsolete | |
| Bathys Portus | "Deep Harbor", the port of Aulis in Boeotia | Bathys Planum, changed to Icaria Planum | |
| Benacus Lacus | "Lake Benacus" | Obsolete | |
| Biblis Fons | "Biblis Fountain", a Carian well near Miletus | Biblis Patera, Biblis Tholus | |
| Bosporium Promontorium | "Cape of the Bosphorus" | ||
| Bosporus/Bosphorus Gemmatus | "Bejewelled Bosphorus" | Bosporos Planum, Bosporus Regio, Bosporos Rupes | |
| Brangæna | Obsolete | ||
| Capri | "Isle of Capri" | Capri Chasma, Capri Mensa | |
| Casius | Mt Casius in Egypt, famous in antiquity for the nearby coastal marshes in which whole armies were reputed to have drowned | Casius quadrangle | |
| Castalia Fons | "Castalian Springs" | ||
| Cebrenia | Land of Cebrenia near Troy | Cebrenia quadrangle | |
| Cecropia | "Land of Cecrops" | ||
| Ceraunius | Ceraunius Catena, Ceraunius Fossae | ||
| Chalce | Chalce Montes | ||
| Charitum Promontorium | "Cape of the Graces" | Charitum Montes | |
| Chironis Fretum | "Strait of Chiron" | ||
| Mare Chronium | Planum Chronium, Chronius Mons | ||
| Chryse | One of a pair of legendary islands, Chryse and Argyre, located in the Indian Ocean and said to be made of gold and silver | Chryse Chaos, Chryse Colles, Chryse Planitia | |
| Chrysokeras | The Golden Horn | ||
| Cimmeria Insula | "Cimmerian Island" | Obsolete | |
| Mare Cimmerium | "Cimmerian Sea", named after an ancient Thracian seafaring people | Terra Cimmeria | |
| Circaeum Promontorium | "Cape of Circe" | ||
| Claritas | Latin for "bright" | Claritas Fossae, Claritas Rupes | |
| Clepsydra Fons | "Water-clock fountain", a well in the Athenian acropolis. | ||
| Coprates | River Coprates, now called the Dez, in modern Iran | Coprates quadrangle | |
| Coracis Portus | "Haven of Corax" | ||
| Cyane Fons | "Cyane fountain", a spring in Sicily from which the Cyane river sprang, named for a nymph. | Cyane Catena, Cyane Fossae | |
| Cydonia | poetic name for Crete | Cydonia, Cydonia Mensae, Cydonia Labyrinthus, Cydonia Colles | |
| Cynia Lacus | |||
| Danaïdum Depressio | "Lowland of the daughters of Danaüs" | ||
| Daphne | From Daphne, a nymph pursued by Apollo. | ||
| Deucalionis Regio | "Region of Deucalion" | ||
| Dia | An island north of Crete | ||
| Diacria | Diacria highlands around Marathon | Diacria quadrangle | |
| Dioscuria | "Land of the Dioscuri" | ||
| Eden | From Eden, the biblical paradise | Eden Patera | |
| Edom | From Edom, an ancient kingdom in modern Jordan | ||
| Edom Promontorium | "Cape of Edom" | ||
| Electris | The principal island of the "Electrides", islands said to produce amber. | Electris Mons | |
| Elysium | From Elysium, the Greek land of dead heroes | Elysium Planitia, Elysium Mons, Elysium Fossae, Elysium quadrangle | |
| Eridania | Land of the River Eridanus | Eridania Mons, Eridania Planitia, Eridania quadrangle, Eridania Scopulus | |
| Mare Erythræum | "Red Sea" | Erythraea Fossae |
F-L
| Name | Meaning | Modern name | |
| Famæ Depressio | "Lowland of Fame" | ||
| Ferentinæ Lucus | "Grove of Ferentina" | - | |
| Lucus Feronia | "Grove of Wild Beasts" | - | |
| Flevo Lacus | - | ||
| Gallinaria Silva | - | ||
| Mare Hadriaticum | "Adriatic Sea" Aka Hadriaticum Mare | Hadriacus Mons, Hadriaca Patera | |
| Hammonis Cornu | "Horn of Ammon" | - | |
| Hellas | "Greece" | Hellas Planitia, Hellas Montes, Hellas quadrangle | |
| Heræum Promontorium | "Cape of Hera" | - | |
| Hercynia Silva | Hercynian Forest | ||
| Herculis Columnæ | "Pillars of Hercules" | - | |
| Herculis Pons | "Bridge of Hercules" | - | |
| Hesperia | "Land of the Setting Sun" | Hesperia Dorsa, Hesperia Planum | |
| Hesperidum Lacus | "Lake of the Hesperides | - | |
| Hibe | - | ||
| Hippocrene Fons | "Fountain of Hippocrene", near Mount Helicon | - | |
| Hipponitis Palus | - | ||
| Horarum Promontorium | "Cape of the Hours" | Horarum Mons | |
| Hypelaus | A fountain in Ephesus. | - | |
| Hyperboreus Lacus | Greek/Latin: Far Northern Lake | Hyperboreae Undae | |
| Iapygia | Salento in Italy, ancient home of the Iapyges | Iapygia quadrangle | |
| Icaria | Icaria Fossae, Icaria Planum | ||
| Mare Icarium | - | ||
| Ierne | A name for Ireland | - | |
| Isidis Regio | "Region of Isis" | Isidis Planitia | |
| Ismenius Lacus | The Ismenian Spring near Thebes where Cadmus slew the guardian dragon | Ismenia Patera, Ismeniae Fossae Ismenius Cavus, Ismenius Lacus quadrangle | |
| Jani Fretum | "Strait of Janus" | Iani Chaos | |
| Juventæ Fons | "Fountain of Youth" a.k.a. Fons Juventæ | Juventae Chasma, Juventae Dorsa | |
| Labeatis Lacus | Lake of the Labeates, a people of Illyria | - | |
| Lausonius Lacus | - | ||
| Lemuria | From Lemuria, a fictional sunken land in the Pacific or Indian Ocean | - | |
| Lerne | - | ||
| Libya | "Libya" | Libya Montes | |
| Lucrinus Lacus | The Lucrine Lake in Roman Italy | - | |
| Lunæ Lacus | "Lake of the Moon" a.k.a. Lacus Lunæ'' | Lunae Palus quadrangle, Lunae Planum |
M-N
| Name | Meaning | Modern name | |
| Mæisia Silva | - | ||
| Mapharitis | - | ||
| Mareotis | "Land about Mareota", in Lower Egypt. | Mareotis Fossae | |
| Margaritifer Sinus | "Pearlbearing Bay" | Margaritifer Terra, Margaritifer Sinus quadrangle | |
| Lucus Maricæ | "Grove of Maríca", a nymph of Latium. | Lucus Planum | |
| Memnonia | "Land of Memnon" | Memnonia Fossae, Memnonia quadrangle | |
| Meroë Insula | "Island of Meroe" | Meroe Patera | |
| Messeis Fons | - | ||
| Lacus Mœris | Lake Moeris, a lake in the Egyptian Fayum | ||
| Mons Argenteus | "Silver mountain" | Dorsa Argentea, Argentea Planum | |
| Neith Regio | "Region of Neith" | ||
| Nepheles Depressio | "Lowland of cloud" | - | |
| Nereïdum Promontorium | "Cape of the Nereids | Nereidum Montes | |
| Nerigos | Name of a fictional country, supposedly in or near Scandinavia | - | |
| Nessonis Lacus | - | ||
| Niliacus Lacus | "Lake of the Nile" | Colles Nili | |
| Nilokeras | "Horn of the Nile" | Nilokeras Fossae, Nilokeras Mensae | |
| Nitriæ | - | ||
| Nix Atlantica | "Atlantic Snow" | Obsolete | |
| Nix Olympica | "Olympian Snow" | Olympus Maculae, Olympus Mons, Olympus Patera, Olympus Rupes | |
| Noachis | "Land of Noah" | Noachis quadrangle, Noachis Terra | |
| Nodus Gordii | "Gordian Knot" | Gordii Dorsum | |
| Noti Sinus | "Bay of Notus" | - | |
| Novissima Thyle | "Newest Thule" | - | |
| Nuba Lacus | - |
O-S
| Name | Meaning | Modern name | |
| Mare Oceanidum | "Sea of the Oceanids" | Oceanidum Fossa, Oceanidum Mons | |
| Octantis Depressio | "Lowland of Octans" | Octantis Cavi, Octantis Mons | |
| Œnotria | Oenotria Plana, Oenotria Scopuli | ||
| Ogygis Regio | "Region of Ogyges" | Ogygis Rupes, Ogygis Undae | |
| Ophir | From Ophir, a biblical land of gold | Ophir Catenae, Ophir Cavi, Ophir Chasma, Ophir Planum | |
| Ortygia | Ortygia Colles | ||
| Oxia Palus | Oxeia, a Greek Island in Ionian Sea | Oxia Chaos, Oxia Colles, Oxia Palus quadrangle | |
| Palicorum Lacus | - | ||
| Palinuri Fretum | "Strait of Palinurus" | ||
| Palinuri Sinus | "Bay of Palinurus" | ||
| Pallas Lacus | "Lake of Pallas" | - | |
| Panchaia | From the name of an island supposed to be in South Arabia | Panchaia Rupes | |
| Phaëthontis | "Land of Phaethon or Phaethon " | Phaethontis quadrangle | |
| Phlegra | From a district in Macedonia. | Phlegra Montes | |
| Campi Phlegræi | "Fields of Phlegra" | Phlegra Montes | |
| Phœnicis Lacus | "Lake of the Phoenix" a.k.a. Lacus Phœnicis | Phoenicis Lacus quadrangle | |
| Phrixi Regio | "Region of Phrixus" | Phrixi Rupes | |
| Piscis Depressio | "Depression of the Fish" | - | |
| Depressio Pontica | "Lowland of Pontus" | - | |
| Promethei Sinus | "Bay of Prometheus" | Promethei Terra | |
| Propontis | From an old name for the Sea of Marmara | - | |
| Protei Regio | "Region of Proteus" | - | |
| Pyrrhæ Regio | "Region of Pyrrha" | Pyrrhae Chaos, Pyrrhae Fossae | |
| Rupes Tenuis | Latin: "Thin Cliff" | Tenuis Mensae, Rupes Tenuis | |
| Sinus Sabæus | "Bay of Sheba" Aka Sabaeus Sinus | Terra Sabaea, Sinus Sabaeus quadrangle | |
| Scandia | From a name for Skåne or Scandinavia | Scandia Cavi, Scandia Colles, Scandia Tholi | |
| Scheria Insula | "Scheria Island" | - | |
| Semiramidis Lacus | "Lake of Semiramis" | - | |
| Serapium | - | ||
| Simoëntis Sinus | "Bay of Simois" | Simois Colles | |
| Sirbonis Palus | The army-swallowing Serbonian Bog near Mt Casius in Egypt | Obsolete | |
| Mare Sirenum | "Sea of Sirens" | Terra Sirenum | |
| Socratis Promontorium | "Cape of Socrates" | ||
| Solis Fons | "Fountain of the Sun" | Obsolete | |
| Solis Lacus | "Lake of the Sun" | Solis Planum | |
| Stygis | "Styx River", Greece | Stygis Catena, Stygis Fossae | |
| Syrtis Major | a Libyan gulf, now Gulf of Sidra | Syrtis Major Planum, Syrtis Major quadrangle | |
| Syrtis Minor | now Gulf of Gabès in Tunisia. a.k.a. Syrtis Parva | - |
T-Z
| Name | Meaning | Modern name | |
| Tempe | Vale of Tempe, Greece | Tempe Fossae, Tempe Terra | |
| Tharsis | "Tarshish" ancient source of ship-loads of silver. Possibly Tartessos or Sardinia | Tharsis Montes, Tharsis quadrangle | |
| Thaumasia | "Land of Wonders" | Thaumasia Planum, Thaumasia quadrangle | |
| Thyle I | "First Thule" | Thyles Montes, Thyles Rupes | |
| Thyle II | "Second Thule" | ||
| Thyles Collis | "Hill of Thule" | - | |
| Thyles Mons | "Mountain of Thule" | - | |
| Thymiamata | "Incenses" | - | |
| Tiphys Fretum | - | ||
| Titanum Sinus | "Bay of the Titans" | - | |
| Tithonius Lacus | Tithoniae Catenae, Tithoniae Fossae, Tithonium Chasma | ||
| Trinythios | - | ||
| Trivii Fons | "Fountain of the Crossroads" | - | |
| Trivium Charontis | "Crossroads of Charon" | - | |
| Mare Tyrrhenum | "Tyrrhenian Sea" | Mare Tyrrhenum quadrangle, Tyrrhenus Mons, Tyrrhena Terra | |
| Uchronia | "Nowhen" | - | |
| Ulyxis Fretum | "Strait of Ulysses" | Ulyxis Rupes | |
| Utopia | "Nowhere, Utopia" | Utopia Planitia | |
| Vulcani Pelagus | "Sea of Vulcan" | - | |
| Xanthi Sinus | "Bay of Xanthus" | Xanthe Dorsa, Xanthe Terra | |
| Xisuthri Regio | "Region of Xisuthrus" | - | |
| Yaonis Regio | "Region of Emperor Yao" | - | |
| Zephyria | "Land of the West Wind " | Zephyria Planum, Zephyria Mensae |