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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1333
silicic acid
  اسید سیلیسیک   
asid silisik (#)

Fr.: acide silicique   

A general name for a family of chemical compounds containing the element silicon attached to oxide and hydroxyl groups.

silicic; → acid.

silicon
  سیلیسیوم   
silisiom (#)

Fr.: silicium   

A non-metallic chemical element; symbol Si. Atomic number 14; atomic weight 28.0855; melting point 1,410°C; boiling point 2,355°C; specific gravity 2.33 at 25°C. It occurs in a combined state in minerals and rocks and constituting more than one fourth of the earth's crust.

From silic(a), from L. silex (genitive silicis) "flint, pebble" + -on, as in carbon and boron.

Silisiom, from Fr. silicium, from silic(a), as above, + -ium as in magnesium, barium.

silicon burning
  سوزش ِ سیلیسیوم   
suzeš-e silisiom

Fr.: combustion du silicium   

The → nucleosynthetic process taking place in the interior of → massive stars whereby → silicon is transmuted into iron, nickel, and neighboring nuclei collectively called the → iron peak elements.

silicon; → burning.

silk
  ابریشم   
abrišam (#)

Fr.: soie   

The soft, lustrous fiber obtained as a filament from the cocoon of the silkworm (Dictionary.com).

M.E., from O.E. seolc, sioluc, from L. sericum "silk garment, silk," from neuter of sericus "silken," from Gk. serikos, from Seres, an eastern Asian people, probably the Chinese (cf. Chinese si "silk", Manchurian sirghe, Mongolian sirkek).

Abrišam "silk," from Mid.Pers. abrešom "silk," ultimately from Proto-Ir. *au-uris-, from *uris- "to turn, spin;" cf. rešté "thread, line, file," reštan, ristan, "to spin;" Mid.Pers. 'rws- "to turn to;" Av. uruuaēs- "to twist, turn."

Silk damping
  میرایی ِ سیلک   
mirâyi-ye Silk

Fr.: amortissement de Silk   

The smoothing of primordial → density fluctuations at high frequencies caused by photon → diffusion. Before the → decoupling era, photons and → baryons were tightly coupled to each other by → Compton scattering. However, the transition to a transparent → Universe was not instantaneous. As the → opacity of the Universe dropped, the photons started diffusing away from the positions they had while opaque, hence undergoing a → random walk. Since the → acoustic waves in the decoupling era were driven by photon pressure, the photon diffusion also led to damping of the → baryon acoustic oscillations. Silk damping suppresses all perturbations with masses smaller than about 1013 Msun. The implication for a theory of → structure formation is that individual galaxies must have formed in a → top-down structure formation mechanism, i.e. by the fragmentation of larger objects. However, in theories of structure formation which include → non-baryonic dark matter galaxies can form from smaller objects in a → bottom-up scenario.

Joseph Silk (1942-); → damping.

silver
  نقره   
noqré (#)

Fr.: argent   

A metallic → chemical element; symbol Ag (L. argentum). → Atomic number 47; → atomic weight 107.8682; → melting point 961.93°C; → boiling point 2,212°C; → specific gravity 10.5 at 20°C. Pure silver is nearly white, lustrous, soft, very ductile, malleable, and an excellent conductor of heat and electricity.
Silver is generated in stars through a special rapid process of → neutron captures. This process defers from the main → r-process, the main and weak → s-process, and charged particle freeze-outs. In other words, during a → supernova explosion, silver is formed in a different → fusion process from the one that forms → gold (Hansen et al., 2012, A&A 545, A31).

M.E. silver(e), selver(e), selfer; O.E. seolfor "silver;" cf. O.S. silvbar, O.N. silfr, M.Du. silver, Du. zilver, O.H.G. sillabar, Ger. silber, Goth. silubr, akin to Serbo-Croatian srebro, Rus. serebo, Lith. sidabras "silver."
L. argentum "silver, white money," from PIE *arg-ent-, from PIE *arg- "to be bright, shine;" cf. Av. ərəzata- "silver," auruša- "white" (Mid.Pers. arus "white, bright"); O.Pers. ardata- "silver;" Mod.Pers. arziz "silvery metal tin;" Skt. arjuna- "white, shining," rajata- "silver;" Gk. argos "white," arguron "silver;" Arm. arcat; Hittite harki- "white."

Noqré from Sogdian nâkartak "uncoined (silver)," literally "undone," from nâ- negation prefix "not, no" (Mid.Pers. ne, O.Pers. naiy, Av. na-, (particle of negation noit), Skt. na-, (ned), Gk. né- "not," L. ne-, in-, un-, PIE *ne-) + kartak "done," p.p. of kardan "to do, to make;" kâr "work," variant kar (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base kwer- "to do, to make"), Sogdian nâktênê "of silver." Note that another word in Pers. for silver is sim, which has a semantic form comparable to that of noqré, since it derives from Mid.Pers. asêm, from Gk. asemon "without mark, uncoined, shapeless, formless," from argurion asemon "uncoined money."

SIMBAD
     
SIMBAD

Fr.: SIMBAD   

A large on-line astronomical database, developed at the Centre de Données astronomiques de Strasbourg, → CDS in France. It provides a large collection of astronomical data, including cross-identifications, bibliography, and measurements for astronomical objects outside the solar system.

SIMBAD, short for Set of Identifications, Measurements, and Bibliography for Astronomical Data.

similar
  همانند   
hamânand (#)

Fr.: similaire   

1) Geometry: Having the same shape; representing the same figure drawn to different scales (same corresponding angles and proportional sides).
2) Math.: Related by means of a → similarity transformation.

From Fr. similaire, from L. similis "like," → simulate.

Hamânand, contraction of hammânand, from ham-, → com-, + mânand "resembling, like," → simulate.

similar matrices
  ماتریس‌های ِ همانند   
mâtrishâ-ye hamânand (#)

Fr.: matrices similaires   

Two → square matrices A and B that are related by B = X-1AX, where X is a square → nonsingular matrix.

similar; → matrix.

similar polygons
  چندبرهای ِ همانند   
candbarhâ-ye hamânand

Fr.: polygone similaires   

Polygons that are exactly the same shape, but can be different sizes.

similar; → polygon.

similarity
  همانندی   
hamânandi (#)

Fr.: similarité   

The state of being similar; likeness; resemblance.

similar; → -ity.

similarity transformation
  ترادیسش ِ همانندی   
tarâdiseš-e hamânandi

Fr.: transformation de similarité   

1) A transformation that preserves angles and changes all distances in the same ratio.
2) A transformation of the form B = X-1AX relating two → square matrices A and B.

similarity; → transformation.

simple
  ساده   
sâdé (#)

Fr.: simple   

1) Chem.: Composed of only one → substance or → element.
2) Math.: Consisting of, involving, or describable by → terms of the → first degree.
3) Music: Uncompounded or without overtones.

M.E., from O.Fr. simple, from L. simplus "simple, single," variant of simplex, from PIE root *sem- "one, together;" cf. Pers. ham "together," → com-, Skt. sam "together;" + *plac- "-fold," from PIE *plek- "to plait," → multiply.

Sâdé "simple, unmixed, smooth, erased, plain;" cf. Khotanese sāta- "smooth;" Baluchi sāt/sāy-, sāh- "to shave;" Av. si-, sā- "to sharpen, cut;" Skt. śā- "to sharpen, whet" (Cheung 2007); see also → precise.

simple event
  رویداد ِ ساده   
ruydâd-e sâdé

Fr.: événement simple   

Statistics: An event consisting of a single point of the → sample space.

simple; → event.

simple fraction
  برخه‌ی ِ ساده   
barxe-ye sâdé

Fr.: fraction simple   

A fraction in which the → numerator and → denominator are positive → integer numbers. Compare → compound fraction.

simple; → fraction.

simple harmonic motion
  جنبش ِ هماهنگ ِ ساده   
jonbeš-e hamâhang-e sâdé

Fr.: mouvement harmonique   

The motion of a body subjected to a restraining force which is directly proportional to the displacement from a fixed point in the line of motion. The equation of simple harmonic motion is given by x = A sin(ωt + θ0), where x is the body's displacement from equilibrium position, A is the → amplitude, or the magnitude of harmonic oscillations, ω is the → angular frequency, t is the time elapsed, and θ0 is the → initial phase angle.

simple; → harmonic; → motion.

simple harmonic oscillator
  نوشگر ِ هماهنگ ِ ساده   
navešgar-e hamâhang-e sâdé

Fr.: oscillateur harmonique simple   

An oscillator whose force is proportional to its extension, according to → Hooke's law. The way the oscillator moves is called → simple harmonic motion.

simple; → harmonic; → oscillator.

simple population
  پرینش ِ ساده   
porineš-e sâdé

Fr.: population simple   

A set of stars resulting from a spatially (≤ few pc) and temporally (≤ Myr) correlated star formation event.

simple; → population.

simple root
  ریشه‌ی ِ ساده   
riše-ye sâdé

Fr.: racine simple   

A → rootx0 of function f(x), if f(x0) = 0 and df/dx | x0 = 0. See also → double root.

simple; → root.

simplex
  تکتافت   
taktâft

Fr.: simplexe   

A generalization of the simplest closed configuration that can be made from straight line segments. For example, a → triangle is a 2-simplex because it is in two → dimensions, and → tetrahedron is a 3-simplex because it is in three dimensions (Steven Schwartzman, An Etymological Dictionary of Mathematical Terms Used in English, 1994).

Simplex, literally "uncomplicated, → simple," from sim-, from PIE root *sem- "one, once, together" + plek- "to fold." "folded [only] once."

Taktâft, literally "folded once," from tak "→ single, alone," + tâft, contraction of tâfté "plated, twisted, fold," as in hamtâft, → complex.

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