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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


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

<< < "no cen cos for for for inf lin Pla sim top wea > >>

Number of Results: 225 Search : for
centripetal force
  نیروی ِ مرکزگرا   
niru-ye markaz-gerâ (#)

Fr.: force centripète   

The force exerted on an object in → circular motion which is directed toward the center and keeps the body in motion. Centripetal force produces → centripetal acceleration, according to → Newton's second law: Fc = mac. Its direction is always inward along the → radius vector, and its magnitude is given by: Fc= mac = mvt2/r = mω2r.

centripetal; → force.

cluster formation efficiency (CFE)
  کارایی ِ دیسش ِ خوشه   
kârâyiè-ye diseš-e xuše

Fr.: efficacité de formation d'amas   

The fraction of → star formation which happens in → bound clusters. It is defined as the ratio between the → cluster formation rate and → star formation rate (Bastian, 2008, MNRAS 390, 759, arxiv/0807.4687).

cluster; → formation; → efficiency.

cluster formation rate (CFR)
  نرخ ِ دیسش ِ خوشه   
nerx-e diseš-e xuše

Fr.: taux de formation d'amas   

A parameter used in star formation models representing the ratio of the total mass in → star clusters to the corresponding age range (Bastian, 2008, MNRAS 390, 759, arxiv/0807.4687).

cluster; → formation; → rate.

CO formation
  دیسش ِ CO   
diseš-e CO

Fr.: formation de CO   

The chemical reaction that gives rise to → carbon monoxide in the → interstellar medium. According to models, several processes may lead to CO formation. For example, HCO+ + e → CO + H. The molecule HCO+ is itself produced through several paths, for example: H3+ + C → CH2+ + H, CH2+ + H2 → CH3+ + H, CH3+ + O → HCO+ + H. Alternatively: C+ + H2O → HCO+ + H. Another possibility: C+ + OH → CO+ + H, CO+ + H2→ HCO+ + H.

carbon monoxide; → formation.

co-formation theory
  نگره‌ی ِ هم-دیسش   
negare-ye ham-diseš

Fr.: théorie de co-formation   

A theory according to which the Earth and Moon formed from the → protoplanetary disk at the same time. See also → giant impact hypothesis, → capture theory, → fission theory.

co-; → formation; → theory.

coercive force
  نیروی ِ پزورنده   
niru-ye pazurandé

Fr.: force coercitive   

The strength of an external → magnetic field that brings to zero the → magnetic flux density of a magnetic material when that field is caused to operate in the opposite direction from the orientation of the → magnetization of the material. Also called coercivity. Coercive force is a measure of the magnetization of a → ferromagnetic material. It is usually measured in the units of → oersted or ampere/m.

coercive; → force.

cohesive force
  نیروی ِ همدوسش   
niru-ye hamduseš

Fr.: force cohésive, ~ de cohésion   

The force of → attraction between the molecules of the same substance.

cohesive; → force.

collective star formation
  دیسش ِ گرد‌آمدی ِ ستارگان   
diseš-e gerdâmdi-ye setâregân

Fr.: formation collective d'étolies   

Formation of stars, especially → massive stars, in group as opposed to individual formation.

collective; → star; → formation.

collinear forces
  نیروهای ِ هم-خط   
niruhâ-ye ham-xatt

Fr.: forces collinéaires   

A system of two or more forces that lie along the same → line of action.

collinear; → force.

color transformation
  ترادیس ِ رنگ   
tarâdis-e rang

Fr.: transformation de couleur   

Empirical mathematical transformation applied to the observed magnitudes in order to convert them into a standard system, or into a different system.

color; → transformation.

compound angle formula
  دیسول ِ زاویه‌ی ِ همنات   
disul-e zaviye-ye hamnât

Fr.: formule d'angle composé   

One of eight equations that give the → trigonometric functions of → compound angles.
sin(A± B) = sinA.cosnd angleB± cosA.sinB
cos(A + B) = cosA.cosB - sinA.sinB
cos(A - B) = cosA.cosB + sinA.sinB
tan(A + B) = (tanA + tanB)/(1 - tanA.tanB)
tan(A - B) = (tanA - tanB)/(1 + tanA.tanB).

compound; → angle; → formula.

concurrent forces
  نیروهای ِ هاتزنده   
niruhâ-ye hâtazandé

Fr.: forces concourantes   

A system of forces applied to a → rigid body in such manner that their lines of action intersect at a single point. A system of concurrent forces acting on a rigid body can be replaced by an equivalent force applied at the same point. → line of action.

concurrent; → force.

conform
  ۱) همدیسیدن؛ ۲) همدیس شدن   
1) hamdisidan; 2) hamdis šodan

Fr.: 1) conformer; 2) se conformer   

1a) To make similar in form, nature, or character.
1b) To bring into agreement, correspondence, or harmony.
2a) To act in accordance or harmony; comply (usually followed by to).
2b) To be or become similar in form, nature, or character (Dictionary.com).

con-; → form.

conformal
  همدیس   
hamdis

Fr.: conforme   

1) That conforms, especially to the shape of something.
2) Math.: Of, pertaining to, or specifying a mapping of a surface upon another surface so that all angles between intersecting curves remain unchanged.

con- + → form + → -al.

conformal compactification
  همپکانش ِ همدیس   
hampakâneš-e hamdi

Fr.: compactification conforme   

A mapping of an infinite → space-time onto a finite one that may make the far away parts of the former accessible to study. The technique invented by Penrose defines an equivalence class of → metrics, gab being equivalent to ĝab = Ω2gab, where Ω is a positive scalar function of the space-time that modifies the distance scale making the asymptotics of the physical metric accessible to study.

conformal; → compactification.

conformal cyclic cosmology (CCC)
  کیهانشناسی ِ چرخه‌ای ِ همدیس   
keyhânšenâsi-ye carxe-yi-ye hamdis

Fr.: cosmologie cyclique conforme   

A cosmological model developped by Roger Penrose and colleagues according which the Universe undergoes repeated cycles of expansion. Each cycle, referred to an aeon, starts from its own "→ big bang" and finally comes to a stage of accelerated expansion which continues indefinitely. There is no stage of contraction (to a "→ big crunch") in this model. Instead, each aeon of the universe, in a sense "forgets" how big it is, both at its big bang and in its very remote future where it becomes physically identical with the big bang of the next aeon, despite there being an infinite scale change involved, on passing from one aeon to the next. This model considers a conformal structure rather than a metric structure. Conformal structure may be viewed as family of metrics that are equivalent to one another via a scale change, which may vary from place to place. Thus, in conformal space-time geometry, there is not a particular metric gab, but an equivalence class of metrics where the metrics ğab and gab are considered to be equivalent if there is a smooth positive scalar field Ω for which ğab = Ω gab (R. Penrose, 2012, The Basic Ideas of Conformal Cyclic Cosmology).

conformal; → cyclic; → cosmology.

conformal geometry
  هندسه‌ی ِ همدیس   
hendese-ye hamdis

Fr.: géométrie conforme   

The study of the set of angle-preserving transformations on a space.

conformal; → geometry.

conformal mapping
  همتایش ِ همدیس   
hamtâyeš-e hamdis

Fr.: application conforme   

A continuous mapping u = f(x) of a domain D in an n-dimensional Euclidean space (n≥ 2) into the n-dimensional Euclidean space is called conformal at a point x0D if it has the properties of constancy of dilation and preservation of angles at this point.

conformal; → mapping.

coplanar forces
  نیروهای ِ هم-هامن   
niruhâ-ye ham-hâmon

Fr.: forces coplanaires   

A system of forces acting on a body that all are in the same plane.

com- + planar adj. from → plane.

Coriolis force
  نیروی ِ کوریولیس   
niru-ye Coriolis (#)

Fr.: force de Coriolis   

An apparent, rather than real, force exerted on a body when it moves in a rotating → reference frame. Same as the → Coriolis effect.

Coriolis effect; → force.

<< < "no cen cos for for for inf lin Pla sim top wea > >>