An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

Any of the four principal directions or points of the compass, → north, → east, → south, and → west. See also: → cardinal point.

→ cardinal; → direction.

An ordinary number such as 0, 1, 2, or 3, as opposed to an → ordinal number such as 1st, 2nd, or 3rd. Cardinal numbers can be → zero or → positive and are used for counting the things that are assumed to be not divisible.

→ cardinal; → number.

One of the four points where the → meridian and the → prime vertical intersect the → horizon. See also: → cardinal direction.

→ cardinal; → point.

Math.: The → cardinal number indicating the → number of → elements in a → set. For example, the set A = {a, b, c, d} contains 4 elements, and therefore it has a cardinality of 4 (denoted |A| = 4).

→ cardinal; → -ity.

1a) A state of mind in which one is troubled; worry, anxiety, or concern; a cause or object of worry, anxiety, concern, etc.
1b) Serious attention; solicitude; heed; caution.
2a) To be concerned or solicitous; have thought or regard.
2b) To be concerned or have a special preference (Dictionary.com).

M.E., from O.E. caru, cearu "sorrow, anxiety, grief," cognate with Gothic kara, O.H.G. chara lament; M.En. caren, O.E. cearian, carian "be anxious, grieve."

Timâr "care, attendance on the sick; custody; sorrow;" Mid.Pers. têmâr "care; grief"

1) Cautious in one's actions.
2) Taking pains in one's work; exact; thorough.
3) (of things) Done or performed with accuracy or caution (Dictionary.com).

→ care; + -ful, a suffix meaning "characterized by; full of; able to;" → full.

The Keel. A major → constellation in the southern sky, home to → Canopus (α Carinae), the second brightest star after → Sirius. Approximate position: RA 9h, Dec. -60° The constellation resulted from the division of a very large constellation representing → Argo Navis, the mythological Jason's ship. The partition into the constellations → Carina, → Puppis, → Vela, and → Pyxis appeared first on a sky map by Nicholas Louis de Lacaille (1763). Carina represents the bottom of the Ship Argo. Abbreviation: Car; genitive form: Carinae.

L. carina "the keel of a ship, i.e. the principal structural member of a ship, running lengthwise along the center line from bow to stern, to which the frames are attached."

Afzal "keel" in the jargon of the Caspian sea fishermen of Gilan province. Šâh-taxté "main plank."

A → spiral arm in the Milky Way galaxy seen at its best in the → constellation → Carina, but also crossing the constellations → Vela, → Crux, and → Centaurus. It may be a continuation of the → Sagittarius arm; the combined feature is called Sagittarius-Carina arm.

→ Carina; → arm.

One of the most prominent → massive star formation regions of the → Milky Way, also known as NGC 3372. It is associated with a giant → H II region of the same name, which spans about 4 square degrees on the sky and is split by a remarkable V-shaped → dust lane. The Carina Nebula harbors several → star clusters, mainly → Trumpler 14, → Trumpler 16, and Collinder 228, including more than 60 known → O-type stars in addition to the extreme → LBV star → Eta Carinae. This gas and dust complex is associated with a → giant molecular cloud extending over about 130 pc. Large cavities within the molecular cloud are supposed to be carved out by the massive star clusters. There are also several → Herbig-Haro objects and → bipolar outflows.

→ Carina; → nebula.

The fourteenth of Jupiter's known satellites; 40 km in size; → retrograde orbit. It was discovered by Nicholson in 1938.

In Gk mythology, Carme was a wife of Zeus, and the mother of Britomartis, a Cretan goddess.

An experiment devised to produce → interference patterns from a beam of helium atoms passing through two adjacent apertures, as in → Young's experiment.

Named after O. Carnal and J. Mlynek, who first carried out this experiment in 1991 (Phys. Rev. Lett. 66, 2689); → experiment.

A → cyclic process comprising a sequence of → isothermal and → adiabatic expansions and compressions that bring a system back to its initial state.

Nicolas Léonard Sadi Carnot (1796-1832), a French physicist and military engineer who, in his 1824 Reflections on the Motive Power of Fire, gave the first successful theoretical account of heat engines; → cycle.

1) An atom or molecule responsible for an unidentified spectral feature, such as a → diffuse interstellar band.
2) Same as → charge carrier.
3) In radio or television transmission, an → electromagnetic wave whose → amplitude, → frequency, or → phase is to be varied or → modulated to transmit a signal.

Carrier, from v. carry, from M.E. carien, from O. Norm-Fr. carier "to transport in a vehicle," from carre "cart," from L. carrum, carrus "two-wheeled wagon," from Gaul. karros, from PIE *krsos, from base *kers- "to run."

Barandé "carrier," from bordan "to carry," Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," Av. barəθre "to bear (infinitive)," barəθri "a female that bears (children), a mother," Skt. bharati "he carries," Gk. pherein, P.Gmc. *beranan, O.H.G. beran, Goth. bairan "to carry," O.E. beran "bear, bring, wear," PIE root *bher-; "to carry."

A system for counting rotations of the Sun based on the mean → synodic rotation period of the Sun. Initially, Lord Carrington determined the solar rotation rate by watching low-latitude → sunspots. He defined a fixed solar coordinate system that rotates in a sidereal frame exactly once every 25.38 days. This means that the solar rotation period, as viewed from the Earth, is assumed to be constant. However, the synodic rotation rate varies during the year because of the changing speed of the Earth in its orbit and the mean synodic period is about 27.2753 days. Carrington rotation number 1 began on November 9, 1853.

Named for Richard C. Harrington (1826-1875), British astronomer, who initiated the system; → rotation.

Of or relating to René → Descartes, his mathematical system, or his philosophy, especially with regard to its emphasis on logical analysis and its mechanistic interpretation of physical nature. → Cartesian coordinates; → Cartesian vortex theory.

From L. Cartesianus, from Cartesius, Latinized form of the name of French philosopher and mathematician René Descartes (1596-1650), + suffix -ian.

A → coordinate system in which the position of a point is specified by two (in a plane) or three (in 3-dimensional space) → real numbers representing the distances from two perpendicular axes or from three perpendicular planes, respectively. René Descartes (1596-1650) introduced the coordinates system in his La Géométrie in 1637.

→ Cartesian; → coordinate.

A mechanical model put forward before Newton's theory of gravity to explain the revolution of the planets around the Sun. Descartes in his 1644 Principia Philosophiae postulated that the space between the Sun and the planets is filled with matter in the form of a fluid. The fluid rotates in countless whirlpools, one for each planet, thus carrying the planets along in their flow. The vortices vary in size and are contiguous as well as nested. Descartes believed that two objects can exert force on each other only when they are in physical contact. This is why he postulated that space is filled with matter. Newton refuted the vortex theory, using the principle of → action at a distance on which relies his → law of universal gravitation.

→ Cartesian; → vortex; → theory.

A galaxy with a striking ring-like feature lying about 400 million → light-years away in the → constellation  → Sculptor. The ring-like structure, over 100,000 light-years in diameter, is composed of regions of → star formation filled with very bright, → massive stars. The shape results from collision with another smaller galaxy.

Cartwheel, from cart from O.N. kartr; → wheel; → galaxy.

Kahkašân, → galaxy. Carx-e arrâbé "cartwheel," from carx, → wheel + arrâbé "cart, chariot," maybe related to Mid.Pers. ras, ray "wheel," O.Pers./Av. raθa- "wheel," Khotanese rrha- "car," Skt. ratha- "wheel," L. rota "wheel," PIE base *rotos "wheel."

1) A waterfall or a succession of small waterfalls.
2) A succession of stages or processes, as in → cascade shower, → cascade error, → cascade transition.

From Fr., from It. cascata "waterfall," from cascare "to fall," from V.L. *casicare, from L. casum, p.p. of cadere "to fall," → case.

Âbšâr, from âb "water," → Aquarius, + šâr "pouring of water and liquids, waterfall;" peyšâr "waterfall succession," from pey "step, succession," as in peyâpey, + šâr. This word maybe related to Skt. sar- "to flow, run, hurry," Gk. iallo "I send out," L. salio "I jump." It may also be variant of Mod.Pers. cal-, calidan "to walk, be going," car-, caridan "to pasture, graze," Av. car- "to come and go," Skt. cari- "to move, walk, wander."

An error that amplifies as the process of calculation goes on.

→ cascade; → error.