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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

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Number of Results: 722
Rigil Kentaurus (α Centauri)
  پای ِ کنتاؤروس   
pâ-ye Kentâwros

Fr.: Alpha du Centaure   

Another name of → Alpha Centauri.

Rigel, from Ar. rijl (رجل) "foot;" Kentaurus, → Centaurus.

"foot, step" (from Mid.Pers. pâd, pây; Av. pad- "foot;" cf. Skt. pat; Gk. pos, genitive podos; L. pes, genitive pedis; P.Gmc. *fot; E. foot; Ger. Fuss; Fr. pied; PIE *pod-/*ped-); KentâwrosCentaurus.

rigorous
  فرسخت   
farsaxt (#)

Fr.: rigoureux   

1) Severely exact or accurate; precise.
2) Logic, Math.: Logically valid. See also: → accurate, → exact, → precise.

M.E., from M.L. rigorosus, from rigor "stiffness, rigor," from rigere "to be stiff."

Farsaxt, from far- intensive prefix "much, abundant; elegantly" (Mid.Pers. fra- "forward, before; much; around;" O.Pers. fra- "forward, forth;" Av. frā, fərā-, fra- "forward, forth; excessive;" cf. Skt. prá- "before; forward, in fron;" Gk. pro "before, in front of;" L. pro "on behalf of, in place of, before, for;" PIE *pro-) + saxt "hard, strong, firm, secure, solid, vehement, intense" (Mid.Pers. saxt "hard, strong, severe;" Av. sak- "to understand or know a thing, to mark;" cf. Skt. śakta- "able, strong," śaknoti "he is strong," śiksati "he learns").

rigorous selection rule
  رزن ِ گزینش ِ فرسخت   
razan-e gozineš-e farsaxt

Fr.: règle de sélection rigoureuse   

A → selection rule obeyed by → discrete transitions. Among them are: rigorous selection rules for → electric dipole transitions (→ permitted) requiring: 1) ΔJ must be 0 or ± 1 with J = 0 ↔ 0 forbidden. 2) ΔMJ = 0, ± 1. 3) → Parity change, i.e. even ↔ odd.

rigorous; → selection; → rule.

rille
  ریل   
ril

Fr.:   

A long, narrow, straight or sinuous trench or valley with steep walls and roughly parallel sides on the surface of the Moon.

From Ger. Rille "a small rivulet or brook."

Borrowed from E., as above.

rim
  لبه   
labé (#)

Fr.: bord   

The outer edge, border, margin, or brink of something, especially of a circular object.

M.E., from O.E. -rima (in compounds, as in særima "seashore"); cognate with O.Norse rimi "raised strip of land, ridge"

Labé "limb, edge," from lab "lip;" Mid.Pers. lap; cognate with L. labium, E. lip; Ger. Lefze.

rima
  ریما   
rimâ

Fr.: rima   

A long fissure on the surface of a planet or Moon; plural form rimae.

From L. rima "fissure, slit."

Loan from E., as above.

Rindler coordinates
  هماراهای ِ ریندلر   
hamârâhâ-ye Rindler

Fr.: coordonnées de Rindler   

The coordinates that describe the → Minkowski space-time in a → hyperbolic version of → polar coordinates. If the coordinates in an → inertial frame is denoted by (t,x), the Rindler coordinates (η,ξ) are defined by: t = (1/α) eαξ sinh (αη) and x = (1/α) eαξ cosh (αη), where α is some positive constant.

Named after Wolfgang Rindler (1924-), Austrian physicist; → coordinates.

Rindler wedge
  گوه‌ی ِ ریندلر   
gove-ye Rindler

Fr.: coin de Rindler   

A portion of the → space-time described by → Rindler coordinates.

Rindler coordinates; → wedge.

ring
  ۱) حلقه؛ ۲) زنگ   
1) halqé (#); 2) zang (#)

Fr.: 1) anneau; 2) sonnerie   

1) A circular band of something. → gossamer ring.
2) A resonant sound like that of a bell or bells.

O.E. hring "circular band" (cf. O.N. hringr, Ger. Ring), literally "something curved," from PIE base *(s)ker- "to turn, bend."

1) Halqé, loan from Ar. Halqat "ring, hoop, circle."
2) Zang "bell."

ring galaxy
  کهکشان ِ حلقه‌ای   
kahkešân-e halqeyi

Fr.: galaxie en anneau   

A galaxy with a ring-like appearance around the central luminous center. The ring consists of massive, relatively young bright stars. It is believed that ring galaxies result from the head-on collision of two different galaxies.

ring; → galaxy.

ring longitude
  درژنای ِ حلقه   
derežnâ-ye halqé

Fr.: longitude de l'anneau   

Of → Saturn, the angle measured with respect to the sub-observer point (a line connecting the observer to Saturn) in the direction of the orbital motion.

ring; → longitude.

Ring Nebula
  میغ ِ حلقه   
miq-e halqé

Fr.: Nébuleuse de l'Anneau   

A bright → planetary nebula in the constellation → Lyra, also called M57 or NGC 6720. In small telescopes it has the appearance of a slightly elliptical luminous ring around a central hot star (15th magnitude). The radius is one-third of a → light-year, and the nebula is about 2,000 light-years away.

ring; → nebula.

ring opening angle
  زاویه‌ی ِ گشایش ِ حلقه   
zâviye-ye gošâyeš-e halqé

Fr.: angle d'ouverture des anneaux   

Of → Saturn, the angle between the line of sight and the ring plane. Also known as elevation angle, tilt angle.

ring; → open; → angle.

Zâviyé, → angle; gošâyeš "opening," verbal noun from gošudan, gošâdan "to open up, loose, let free;" gošâd "opened; ample, broad;" Mid.Pers. wišâdan "to let free;" Khotanese hīyā "bound;" O.Pers. višta "untied, loosened," vištāspa- "with loosened horses" (personal name); Av. višta "untied," ā-hišāiiā "holds fettered," hita- "fastened, tied on, put to;" cf. Skt. sā- "to bind, fasten, fetter," sitá- "bound," ví-sita- "untied;" halqé, → ring.

ring system
  راژمان ِ حلقه‌ای   
râžmân-e halqe-yi

Fr.: système d'anneaux   

planetary ring system.

ring; → system.

ringdown
     

Fr.: desexcitation finale   

The last stage of → merger between two → black holes undergoing → inspiral. At the end of the evolution of a → binary black hole system, the black holes get close enough to → merge together into a single, larger black hole (→ black hole merger). The resulting black hole is at first distorted and asymmetric, but in the ringdown process the black hole's vibrations decay due to → gravitational radiation leaving finally a quiescent, spinning black hole.

M.E. ring, from O.E. hringan; akin to O.Norse hringja "to ring;" → down.

ringlet
  حلقک   
halqak

Fr.: annelet   

1) A small ring.
2) Any of the thin or narrow rings that compose the major → Saturn's rings.

ring; → -let.

ripple
  چیناو   
cinâv

Fr.: ondulation, ride   

A wave on a fluid surface, of sufficiently short wavelength, in which gravity is the dominant influence.

Of unknown origin, perhaps frequentative of rip (v.) "to tear apart."

Cinâv, literally "water wrinkle," from cin "fold, plait, wrinkle" + âv, variant of âb, → water.

rise
  ۱) بر‌آمدن؛ ۲) بر‌آمد   
1) barâmadan (#); 2) barâmad (#)

Fr.: 1) se lever; 2) lever   

1) Of a heavenly body, to ascend above the horizon. → set.
2) An act or instance of rising; appearance above the horizon. → moonrise, → sunrise

M.E. risen (v.); O.E. risan; cf. O.N. risa, Goth. urreisan "to rise," O.H.G. risan "to rise, flow," Ger. reisen "to travel."

Barâmadan, from bar- "up; upon; on; in; into; at; forth; with; near; before; according to" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + âmadan "to come, to occur, to become" (Mid.Pers. âmatan; O.Pers. gam- "to come; to go," Av. gam- "to come; to go," jamaiti "goes;" Proto-Iranian *āgmatani; Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come").

rising
  بر‌آمد، بر‌آیش   
barâmad (#), barâyeš (#)

Fr.: lever   

The act of rising; the appearance of a celestial body above the horizon. Opposite of → setting.

Verbal noun of → rise.

risk
  ریسک   
risk (#)

Fr.: risque   

Exposure to the chance of injury or loss; a hazard or dangerous chance (Dictionary.com).

From Fr. risque, from It. risco, riscio (modern rischio), from riscare "to run into danger," of uncertain origin.

Risk, loan from Fr.

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