In physical geography, a dune is a hill of sand built by either wind or water flow. Dunes occur in different shapes and sizes, formed by interaction with the flow of air or water. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind. The valley or trough between dunes is called a slack. A "dune field" is an area covered by extensive sand dunes.

Some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. In most cases, the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most widely distributed dunes are those associated with coastal regions, the largest complexes of dunes are found inland in dry regions and associated with ancient lake or sea beds.

Dunes can form under the action of water flow (fluvial processes), and on sand or gravel beds of rivers, estuaries and the sea-bed.

The modern word "dune" came into English from French circa 1790.

Arrakis (/əˈrækᵻs/;Arabic: الراقص‎, ar-rāqiṣ, "the dancer") — informally known as Dune and later called Rakis — is a fictional desert planet featured in the Dune series of novels by Frank Herbert. Herbert's first novel in the series, 1965's Dune, is popularly considered one of the greatest science fiction novels of all time, and it is sometimes cited as the best-selling science fiction novel in history.

In Dune, the planet is the home of the Fremen (Zensunni wanderers), and subsequently is the Imperial Capital of the Atreides Empire. Arrakis is the third planet orbiting the star Canopus, and it in turn is orbited by two moons, one of which has the image of the desert kangaroo mouse, Muad'Dib, on it; the other moon possesses the image of a human hand.

Environment and the spice

A desert planet with no natural precipitation, in Dune it is established that Arrakis had been "His Imperial Majesty's Desert Botanical Testing Station" before the discovery of melange, for which it is the only natural source in the universe. Melange (or, "the spice") is the most essential and valuable commodity in the universe, as it extends life and makes safe interstellar travel possible (among other uses). The planet has no surface water bodies, but open canals called qanats are used "for carrying irrigation water under controlled conditions" through the desert. The Fremen collect water in underground reservoirs to fulfill their dream of someday terraforming the planet, and pay the Spacing Guild exorbitant fees in melange to keep the skies over Arrakis free of any satellites which might observe their efforts. As indicated by its large salt flats, Arrakis once had lakes and oceans; Lady Jessica also notes in Dune that wells drilled in the sinks and basins initially produce a "trickle" of water which soon stops, as if "something plugs it."

Dune is a feature on Earth's Moon, a crater in the Hadley–Apennine region. Astronauts David Scott and James Irwin visited the south rim of it in 1971, on the Apollo 15 mission, during EVA 2. The south rim of Dune was designated Geology Station 4 of the mission.

Dune is located about 1.8 km east of Hadley Rille, less than 1 km south of the smaller Earthlight crater, and about 3 km south of the Apollo 15 landing site itself.

The crater was named by the astronauts after the novel by Frank Herbert, and the name was formally adopted by the IAU in 1973.

Samples

The following samples were collected from Dune Crater (Station 4), as listed in Table 5-II of the Apollo 15 Preliminary Science Report. Sample type, lithology, and description are from Table 5-IV of the same volume.

Samples 15470 to 15476 were collected near where the rover was parked to the south of the rim of Dune. Samples 15485, 15486, and 15499 were collected from the largest boulder in the photograph above. Sample 15498 was collected nearby.

Brabant may refer to:

Historical use

Place names in Europe

In the Netherlands:

In Belgium:

The County of Brabant (1085–1183) was a small medieval area of land located west of Brussels, between the Dender and Zenne rivers in the Low Countries, part of the Holy Roman Empire.

Before 1085 the land had belonged to Hermann II, Count Palatine of Lotharingia. Upon his death, Emperor Henry IV assigned this fief to Henry III, Count of Louvain (Leuven) and Count of Brussels, as the Landgraviate of Brabant. This is the earliest known use of the term Landgrave.

In 1183 Frederick Barbarossa elevated the Landgrave, Henry I, to be Duke of Brabant; the lands of the Counts of Louvain and Brussels and of the Landgrave of Brabant were merged in the Duchy of Brabant.

The area made up part of South Brabant from 1815 to 1830 as part of the United Kingdom of the Netherlands, and part of the Belgian Province of Brabant from 1830 to 1996. It is currently in the western part of Flemish Brabant in the Flemish Region of Belgium.

The Duchy of Brabant was a State of the Holy Roman Empire established in 1183. It developed from the Landgraviate of Brabant and formed the heart of the historic Low Countries, part of the Burgundian Netherlands from 1430 and of the Habsburg Netherlands from 1482, until it was partitioned after the Dutch revolt.

Present-day North Brabant (Staats-Brabant) was adjudicated to the Generality Lands of the Dutch Republic according to the 1648 Peace of Westphalia, while the reduced duchy remained part of the Southern Netherlands until it was conquered by French Revolutionary forces in 1794. Today all the duchy's former territories are in Belgium except for the Dutch province of North Brabant.

Geography

The Duchy of Brabant was historically divided into four parts, each with its own capital. The four capitals were Leuven, Brussels, Antwerp and 's-Hertogenbosch. Before 's-Hertogenbosch was founded, Tienen was the fourth capital.

Its territory consisted essentially of the three modern-day Belgian provinces of Flemish Brabant, Walloon Brabant and Antwerp, the Brussels-Capital Region and most of the present-day Dutch province of North Brabant. Its most important cities were Brussels, Antwerp, Leuven, Breda, 's-Hertogenbosch, Lier and Mechelen.