An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir cla clo clo clu coa coe coh col col col com com com com com com com com com con con con con con con con con con con con coo cor cor cor cos cos cos Cou cou Cra Cre cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis div dog Dop dou dra dua dus dwa dyn e-m ear ecl eco eff ein Ein elb ele ele ele ele Els emi emp ene enr env epi equ equ Eri est Euc eva evo exc exc exh exo exp exp ext ext f-n Fah fam fau fee Fer fib fil fin fir fix fle flu foc for for for fra fre fre fri fun fuz gal gal gal Gan gau GCN gen geo geo geo geo Gl glo gra gra gra gra gra gre gro GW1 hab hal han HAR haz hea hel hel Hen Her heu Hig Hil hol hop hor hou Hub Hum Hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind ine inf inf inf inh INP ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos Jun K2 Kep key kin Kol lag lam Lan lar las lav lea leg len lev lig lim lin lin lin lis lob loc log lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mea mee Men mer met met met mic mid Mil min Mir mix mod mod mol mon Mor mou mul muo mys nan nat nav nec Nep neu New New NGC nob nom non non nor not nuc nuc num Nyq obj obs obs oce oen OH omn opa ope opt opt opt orb ord Ori ort osc out ove oxy pal pan par Par par par pas pea Pen per per per per per pet pha pho pho pho phy pie Pit Pla pla pla pla ple Poi pol pol pol pol pop pos pos pow pre pre pre Pre pri pri pri pro pro pro pro pro pro Pro pub pul pyr qua qua qua qua Qui rad rad rad rad rad rad ram ran rat rea rec rec rec red ref ref reg reg rel rel rem rep res res res ret rev rho Rie rim riv rol Ros rot rul S a Sah san Sat sca Sch Sch scr sec sec sec sei sel sem sep set sha she sho sid sig sil sim sin sit sky slu sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sun sup sup sup sup sur syl syn sys tal Tay tel ten ter tex the the the thi tho thu tid tim tod top tot tra tra tra tra tri tri tro tru tur twi Typ UFO ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis voc von wak Was wav wax wea wei whi Wie win WN6 wom X-r yel you zer zod > >>

Number of Results: 12948 Search : far
reddening parameter
  پارامون ِ سرخش   
pârâmun-e sorxeš

Fr.: paramètre de rougissement   

A dimensionless quantity characterizing the → interstellar extinction, defined by the total-to-selective extinction ratio: RV = AV/E(B-V). The typical value found for the reddening parameter in the Milky Way is RV ~ 3.1, but it is known to vary from one line of sight to another, from values as 2 to as large as 6. Very large → dust grains would produce extinction with RV → ∞.

reddening; → parameter.

reddening vector
  بُردار ِ سرخش   
bordâr-e sorxeš

Fr.: vecteur de rougissement   

A vector indicating the direction in which interstellar reddening moves the position of a star in a multi-dimensional space of color indices.

reddening; → vector.

redshift
  سرخ‌کیب   
sorxkib

Fr.: décalage vers le rouge   

A shift in the lines of an object's spectrum toward longer wavelengths. Redshift indicates that an object is moving away from the observer. The larger the redshift, the faster the object is moving. Redshift is expressed by z = Δλ/λ = v/c, where λ is the wavelength, Δλ the wavelength shift, v the velocity of the source relative to the observer, and c the → speed of light. When v approaches c, redshift is expressed by the → relativistic formula z = ((1 +v/c)/(1 - v/c))½ - 1.

red; → shift.

redshift space
  فضای ِ سرخ-کیب   
fazâ-ye sorx-kib

Fr.: espace de décalage vers le rouge   

The space corresponding to → redshift measurements, as contrasted with real space. See also → redshift space distortion

redshift; → space.

redshift space distortion
  چولگی ِ فضای ِ سرخ-کیب   
cowlegi-ye fazâ-ye sorx-kib

Fr.: distorsion dûe aux vitesses particulières sur la ligne de visée   

The distortion observed in → redshift space of → galaxy clusters caused by peculiar velocities of the members (→ peculiar velocity). In a perfectly homogeneous → Friedmann-Lemaitre Universe the redshifts would accurately measure radial distances from the observer, and the mapping from real space to redshift space would simply be an identity. In an inhomogeneous Universe the peculiar velocities associated with any inhomogeneous structure will introduce a distortion in this mapping (N. Kaiser, 1987, MNRAS 227, 1). See also: → fingers of God, → Kaiser effect.

redshift; → space; → distortion;.

redshift survey
  بردید ِ سرخ‌کیب   
bardid-e sorx kib

Fr.: relevé de décalages vers le rouge   

A survey of a large region of the sky to measure the redshifts of all the galaxies down to a certain limiting magnitude.

redshift; → survey.

redshift-distance relation
  بازانش ِ سرخ‌کیب-دورا   
bâzâneš-e sorxkib-durâ

Fr.: relation décalage vers le rouge-distance   

The correlation, first established by E. Hubble, between the cosmological recession velocities of galaxies and their distances.

redshift; → distance; → relation.

redshifted line
  خط ِ سرخ‌کیبیده   
xatt-e sorx kibideh

Fr.: raie décalée vers le rouge   

A spectral line whose wavelength does not coincide with its theoretical value and is shifted toward longer wavelengths.

red; → shift; → line.

reduce
  ۱) باز‌هاختن، باز‌هازیدن؛ ۲) کاستن   
1) bâzhâxtan, bâzhâzidan; 2) kâstan

Fr.: réduire   

1) To bring to a certain state, condition, arrangement, etc.
Math.: To change the denomination or form, but not the value, of (a fraction, polynomial, etc.).
Chem.: To add an electron to.
2) To bring down to a smaller extent, size, amount, number, etc.; synonymous with → decrease.

M.E. reducen "to lead back," from O.Fr. reducer, from L. reducere, from → re- "back" + ducere "to bring, to lead."

From bâz-, → re- + Mid.Pers. hâxtan, hâzidan "to lead, guide, persuade," Av. hak-, hacaiti "to attach oneself to, to join," cf. Skt. sacate "accompanies, follows," Gk. hepesthai "to follow," L. sequi "to follow;" PIE *sekw- "to follow."
Kâstan, → decrease.

reduced mass
  جرم ِ بازهازیده   
jerm-e bâhâzidé

Fr.: masse réduite   

The "effective" → inertial mass appearing in the → two-body problem of → Newtonian mechanics. The reduced mass is a quantity which allows the two-body problem to be solved as if it were a one-body problem. For the masses m1 and m2, it is given by the ratio μ = m1m2 / (m1 + m2). The value of μ is generally smaller than m1 and m2. The larger the difference between the two masses, the closer μ will be to the smaller mass. If the particles are of equal mass, μ is half the mass of either.

reduce; → mass.

reduced Planck constant
  پایای ِ پلانک ِ باز‌هازیده   
pâyâ-ye Planck-e bâzhâzidé

Fr.: constante de Planck réduite   

The → Planck constant divided by 2π and denoted ħ, pronounced h-bar. Also called the → Dirac constant.

Reduced, p.p. of → reduce; → Planck's constant.

reduced Planck's constant
  پایای ِ پلانک ِ باز‌هازیده   
pâyâ-ye Planck-e bâzhâzidé

Fr.: constante de Planck réduite   

reduced Planck constant.

reduced Planck constant.

reducing agent
  کنشگر ِ بازهازنده   
konešgar-e bâzhâzandé

Fr.: réducteur   

A substance which removes → oxygen from, or adds → hydrogen, to another substance. In the more general sense, one which loses electrons. Also called → reductant.

reduce; → -ing; → agent.

reducing atmosphere
  جوّ ِ باز‌هازنده، هواسپهر ِ ~   
javv-e bâzhâzandé, havâsepehr-e ~

Fr.: atmosphère réductrice   

1) An atmospheric condition in which oxidation is prevented by removal of oxygen and other oxidating gasses or vapours. Usually nitrogen or hydrogen gas is used in order to produce specific effects, e.g. on ceramic wares being fired.
2) An atmosphere of a planet or moon which has a high hydrogen content, either in the form of free hydrogen or hydrogen-containing compounds, such as methane or ammonia. The early atmosphere of Earth is thought to be reducing, dominated by carbon dioxide.

Reducing verbal adj. of → reduce; → atmosphere.

reductant
  بازهازنده   
bâzhâzandé

Fr.: réducteur   

Same as → reducing agent.

Agent noun from → reduce.

reductio ad absurdum
  باز‌هازش به یاوه   
bâzhâzeš bé yâvé

Fr.: raisonnement par l'absurde   

Logic, Math.: A method of → reasoning in which one assumes some statement to be → true and from that → assumption proceeds to deduce a logical → absurdity and hence to a conclusion that the original assumption must have been → false.

L. reductio ad absurdum "reduction to absurdity," → reduction; → absurd.

reduction
  باز‌هازش   
bâzhâzeš

Fr.: réduction   

1) In → data processing, the transformation of data from a "raw" form to some usable form.
2) Chem.: The removal of → oxygen from a substance, or the addition of → hydrogen to it. The term is also used more generally to include any reaction in which an atom gains → electrons.

Verbal noun of → reduce.

redundancy
  افزون‌آیی   
afzun-âyi

Fr.: redondance   

The fact of repeating or duplicity.
That part of the data content that can be dropped without any significant loss of the original information.

From L. redundantia "an overflowing, excess," from redundare "to flow back, overflow, be excessive," from → re- "again" + undare "rise in waves," from unda "a wave."

Afzun-âyi "redundancy, superabounding," from afzun "more, greater; more ample," from afzudan "to add, increase" (Mid.Pers. abzudan "to increase, grow;" O.Pers. abijav- "to increase, add to, promote," from abi-, aiby- "in addition to; to; against" + root jav- "press forward;" Av. gav- "to hasten, drive;" Sk. jav- "to press forward, impel quickly, excite," javate "hastens") + âyi verbal noun of ây- present stem of âmadan "to come, arrive, become" (Av. ay- "to go, to come," aēiti "goes;" O.Pers. aitiy "goes;" Skt. e- "to come near," eti "arrival;" L. ire "to go;" Goth. iddja "went," Lith. eiti "to go;" Rus. idti "to go").

Rees-Sciama effect
  اسکر ِ ریز-سیاما   
oskar-e Rees-Sciama

Fr.: effet de Rees-Sciama   

The → Sachs-Wolfe effect in which the calculations are extended to nonlinear mass concentrations. In the non-linear regime of large-scale → structure formation the → gravitational potential changes with time, and photons climb out of a → potential well slightly different from the one that they fell into. Therefore, nonlinear density fluctuations produce extra evolution of the potentials against the background expansion. On large scales, the nonlinear contribution to the full ISW effect is expected to be dominated by the linear ISW effect in a Universe with → cosmological constant (Seljak, 1996, ApJ 460, 549).

Martin J. Rees (1942-) & Dennis W. Sciama (1926-1999), 1968, Nature 217, 511; → effect.

refer
  بازبردن   
bâzbordan (#)

Fr.: référer   

1) To direct for information or anything required.
2) To hand over or submit for information, consideration, decision, etc.
3) To have relation; relate.
4) To make reference or allusion (Dictionary.com).

M.E. referren, from L. referre "to bring back," from → re- "back" + ferre "carry, bear," cognate with Pers. bordan "to carry, bear," as below.

Bâzbordan, literally "to bring back," from bâz "back," → re- + bordan "to carry, bear" (Mid.Pers. burdan, O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive)," Skt. bharati "he carries," Gk. pherein, L. fero "to carry;" PIE base *bher- "to carry").

<< < -es -iv -ti 21- A r abe abs abs acc acc acc act act ada adi adu aff age alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg ari art ass ast ast ast atm ato att aur aut axi B r bac Bal Bar Bar Bay bec Ber Bet Bie bij bin bio bis bla bla blu blu bol Bor bou Bra bre bro Bug C-s cal Cam can car Car Cas cat cav cel cen cer Cha cha cha che cho cir cir cir cla clo clo clu coa coe coh col col col com com com com com com com com com con con con con con con con con con con con coo cor cor cor cos cos cos Cou cou Cra Cre cri cro cub cur cyc cyl dar dat daw de- Deb dec dec dee def deg del Den dep der det deu dew dic dif dif dil dip dir dis dis dis dis dis div dog Dop dou dra dua dus dwa dyn e-m ear ecl eco eff ein Ein elb ele ele ele ele Els emi emp ene enr env epi equ equ Eri est Euc eva evo exc exc exh exo exp exp ext ext f-n Fah fam fau fee Fer fib fil fin fir fix fle flu foc for for for fra fre fre fri fun fuz gal gal gal Gan gau GCN gen geo geo geo geo Gl glo gra gra gra gra gra gre gro GW1 hab hal han HAR haz hea hel hel Hen Her heu Hig Hil hol hop hor hou Hub Hum Hyd hyd hyd hyp hys ide ign ima imp imp inc inc ind ine inf inf inf inh INP ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jos Jun K2 Kep key kin Kol lag lam Lan lar las lav lea leg len lev lig lim lin lin lin lis lob loc log lor low lum lun lun Lym Mac mag mag mag mag mag mai Mal mar mas mas mat max mea mea mee Men mer met met met mic mid Mil min Mir mix mod mod mol mon Mor mou mul muo mys nan nat nav nec Nep neu New New NGC nob nom non non nor not nuc nuc num Nyq obj obs obs oce oen OH omn opa ope opt opt opt orb ord Ori ort osc out ove oxy pal pan par Par par par pas pea Pen per per per per per pet pha pho pho pho phy pie Pit Pla pla pla pla ple Poi pol pol pol pol pop pos pos pow pre pre pre Pre pri pri pri pro pro pro pro pro pro Pro pub pul pyr qua qua qua qua Qui rad rad rad rad rad rad ram ran rat rea rec rec rec red ref ref reg reg rel rel rem rep res res res ret rev rho Rie rim riv rol Ros rot rul S a Sah san Sat sca Sch Sch scr sec sec sec sei sel sem sep set sha she sho sid sig sil sim sin sit sky slu sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spl spr sta sta sta sta sta ste ste sti sto str str sub sub sub sug sun sup sup sup sup sur syl syn sys tal Tay tel ten ter tex the the the thi tho thu tid tim tod top tot tra tra tra tra tri tri tro tru tur twi Typ UFO ult unc uni uni uni upg ura uti val var vec vel ver ver vig vir vis voc von wak Was wav wax wea wei whi Wie win WN6 wom X-r yel you zer zod > >>