Collis (plural: colles , from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...

word for "hill") is a small

hill A hill is a landform that extends above the surrounding terrain. It often has a distinct summit. Terminology The distinction between a hill and a mountain is unclear and largely subjective, but a hill is universally considered to be not as ...

or knob on a celestial body. The term is used in

planetary nomenclature Planetary nomenclature, like terrestrial nomenclature, is a system of uniquely identifying features on the surface of a planet or natural satellite so that the features can be easily located, described, and discussed. Since the invention of the tel ...

: it is a part of international proper names of such features. Like other generic terms, it is capitalized and stands after the proper name (for example, '' Bilbo Colles''; the only exception is '' Colles Nili'' on Mars). As of 2015, only groups of the hills have names, and the term is used only in plural. Like the other terms of planetary nomenclature, this word describes only external view of the features, but not their origin or geological structure. So, it is used for hills of any origin. Names of bigger (especially domical) uplands usually contain the term ''

Tholus In planetary nomenclature, a tholus (pl. tholi ) is a small domical mountain or hill. The word is from the Greek θόλος, ''tholos'' (pl. ''tholoi''), which means a circular building with a conical or vaulted roof. The Romans transliterated th ...

'' ("dome"), and the names of still bigger mountains – the term ''

Mons Mons (; German and nl, Bergen, ; Walloon and pcd, Mont) is a city and municipality of Wallonia, and the capital of the province of Hainaut, Belgium. Mons was made into a fortified city by Count Baldwin IV of Hainaut in the 12th century. ...

'' ("mountain"). Peculiar round mountains, which are found on Venus, get names with the term '' Farrum''. The term ''Collis'' was introduced into planetary nomenclature in 1982, on XVIIIth General Assembly of

International Astronomical Union The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreach ...

. This year two groups of hills on Mars were named (''

Ariadnes Colles Ariadnes Colles is a region of colles (hills) in the northeast of Eridania quadrangle of Mars. It is located around 34.5 ° south latitude, and 172.78° east longitude. It covers . The feature was named after a classic albedo feature by the IA ...

'' and '' Deuteronilus Colles''). As of May 2015, 43 such groups are named: 22 on Mars, 16 on Venus and 5 on Titan. On different celestial bodies they are named differently: * on

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...

, after sea goddesses * on

Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin atmos ...

, after nearby

albedo feature An albedo feature is a large area on the surface of a planet (or other Solar System body) which shows a contrast in brightness or darkness (albedo) with adjacent areas. Historically, albedo features were the first (and usually only) features to b ...

s on classical maps by

Giovanni Schiaparelli Giovanni Virginio Schiaparelli ( , also , ; 14 March 1835 – 4 July 1910) was an Italian astronomer and science historian. Biography He studied at the University of Turin, graduating in 1854, and later did research at Berlin Observatory ...

or Eugène Antoniadi * on Titan, after characters from Tolkien's

Middle-earth Middle-earth is the fictional setting of much of the English writer J. R. R. Tolkien's fantasy. The term is equivalent to the '' Miðgarðr'' of Norse mythology and ''Middangeard'' in Old English works, including ''Beowulf''. Middle-earth i ...

* on

Pluto Pluto (minor-planet designation: 134340 Pluto) is a dwarf planet in the Kuiper belt, a ring of bodies beyond the orbit of Neptune. It is the ninth-largest and tenth-most-massive known object to directly orbit the Sun. It is the largest k ...

, after pioneering spacecraft Olosa Colles (Magellan) part.png, Part of '' Olosa Colles'' on Venus Acidalia Colles (THEMIS) part.png, Part of '' Acidalia Colles'' on Mars Nimloth Colles (Cassini, T43).png, '' Nimloth Colles'' on Titan

References

Links

* Current lists of features with the term ''Colles'' in the name
on Venuson Marson Titan
* {{commonscat-inline, Colles, Colles * Planetary geology