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 p abe abs abs aca acc acc acr act ada adh Adr aer aga air Alf Alg alk Alp alt alu amm ana And ang ani ano ant ant Ap apo app app Aqu Arc arg arr asc ass ast ast asy atm ato att aur aut axi B-m bad Bal bar bar Bay Bed ber Bet bif bim bin bio bis bla ble blu Bod Bol bor bou Bra Bre bro bul C-t Cal Cam can car Car Cas cat cav cel cen cer Cha cha Cha che chl Cir cir cir Cla cli clo clu co- coc coh col col col Com com com com com com com com Com con 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 Dan dat Dav de- Deb dec dec dee def deg del Den den der det deu dew dic dif dif dil Dip dir dis dis dis dis dis diu dod Dop dou Dra dua dus dwa dyn DZ Ear ecc eco edi EHB Ein ela ele ele ele ele ell eme emp end Eng ent epi equ equ era ESP eth Eur evi exa exc exe exi exp exp ext ext ext fac fal far fec Fer fer fie fin fir fis fla Flo flu fog for for Fou fra fre fre Fro fun G s Gal gal gal Gar gau geg gen geo geo geo ger gla gly gra gra gra gra gra Gre gro GYR Had Hal hap Har HD hea hel hel Hen Her hex hig Hil hol Hoo hor hou Hub hum hyb hyd hyd hyp hys ide ign ima imp imp in- inc Ind ind ine inf inf inf ini ins ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jor jum K c Kep Ker kin kno lab Lam Lan Lap las lat Le lef len lev lig lig lin lin lin liq Lit loc log lon lou LS lun lun Lym M s Mag mag mag mag mag mag maj man Mar mas mas mat May mea mec mel mer mes met met met mic mid mil Min Mir mix mod mod mol mon mor mov mul mur mys nan nat nav nec Nep neu New New NGC nob nom non non nor nos nuc nuc num nut obj obl obs occ oct off oli oni ope opp opt opt orb ord org orp osc out ove oxi P-w pal par par par par Pas pat pej per per per per per per pha Phe pho pho pho phy pin pla Pla pla pla pla plu poi pol pol Pol pol por pos pot Poy pre pre pre pre pri pri pri pro pro pro pro pro pro Psa pul pum Q i qua qua qua qua R A rad rad rad rad rad rad Ram Ran rat rea rea rec rec red red ref ref reg rei rel rel rem rep res res res ret rev Rho Rie ril riv rog Ros rot rul S A Sag sam sat sca sca Sch Sco Sec sec sec seg sel sem sen set Sha sha shi sho sid sig sim sin Sir ske sli Smo soc sof sol sol sol sol sou sou spa spe spe Spe spe sph spi Spi spr sta sta sta sta sta ste ste ste Sto str str sub sub sub suc sun sup sup sup sup sur swa syn syn tac tas tel tem ter tes the the the the thi thr tid til tip ton tor tou tra tra tra tra Tri tri tru tsu tur two Typ UHE ult unc uni uni uni upg ura uti val var vec Vel ver Ver vie Vir vis vis vol W-R war wav wav wea Wei wha wid win WN3 Wol wri xen yok zen zij > >>

Number of Results: 13116 Search : far
spin temperature
  دمای ِ اسپین   
damâ-ye espin

Fr.: température de spin   

The → excitation temperature of the → hyperfine structure levels of the → neutral hydrogen21-centimeter line.

spin; → temperature.

spin-down
  کند-چرخی   
kond-carxi

Fr.: ralentissement   

A phenomenon in which the rotation period of a pulsar steadily decreases with the pulsar age. The cause of the spin-down is magnetic torque due to the strong fields threading out from the pulsar. The magnetic energy is being converted to high-energy particles and radiation from the nebula. Observed spin-down rates range from about 10-5 seconds/year for the youngest pulsars to about 10-12 seconds/year for recycled pulsars. The Crab pulsar is slowing down at a rate of about 10-5 seconds/year. Knowing the rotation period and the lengthening rate of a pulsar leads to its age.

spin; down, M.E.; O.E. ofdune "downward," from dune "from the hill."

Kond-carxi, from kond "slow; dull" + carxrotate + -i noun suffix.

spin-flip scattering
  پراکنش با وارونی ِ اسپین   
parâkaneš bâ vâruni-ye espin

Fr.: diffusion avec renversement du spin   

Quantum mechanics: The scattering of a particle that reverses the spin direction.

spin; flip, from flip-flap; → scattering.

Parâkaneš, → scattering; "with;" vâruni, noun from vârun, → inverse; espin, → spin.

spin-orbit coupling
  جفسری ِ اسپین-مدار، جفتش ِ ~   
jafsari-ye espin-madâr, jofteš-e ~

Fr.: couplage spin-orbite   

1) Astro.: A relationship between the orbital period of one body around another and its rotational period on its axis. The relationship results from tidal forces between the two bodies. For example, the rotation period of the Moon equals its revolution period around the Earth.
2) Quantum mechanics: The interaction between a particle's → spin angular momentum and its → orbital angular momentum.

spin; → orbit; → coupling.

spindle
  دوک   
duk (#)

Fr.: fuseau   

1) A rounded rod, usually of wood, tapering toward each end, used in hand-spinning to twist into thread the fibers drawn from the mass on the distaff, and on which the thread is wound as it is spun (Dictionary.com).
2) → Spindle Galaxy.

M.E. spindel, O.E. spin(e)l, from spinnan, → spin.

Duk "spindle," variants dêk, dik, ultimately from Proto-Ir. *dau- "to run;" cf. Pers. dow-, davidan "to run" (Cheung 2007).

Spindle Galaxy
  کهکشان ِ دوک   
kahkešân-e duk

Fr.: galaxie du Fuseau   

Same as → NGC 5866.

spindle; → galaxy.

spine
  خار   
xâr (#)

Fr.: épine   

1) In 3D → magnetic reconnection models of solar plasma, a field line crossing the → fan at the → magnetic null point. See also → fan (Lau & Finn. 1990, ApJ 350, 672; Parnell et al. 1996, Physics of Plasmas 3, 759).
2) A very narrow line of light extending back from the coma into the tail of some → comets.

M.E., from O.Fr. espine, from L. spina "backbone," originally "thorn, prickle," cf. L. spica "ear of corn," O.N. spikr "nail;" from PIE *spei- "sharp point."

Xâr "spine, thorn," related to xal-, xalidan "to prick, to pierce," xâridan "to scratch, itch;" Av. xvara- "wound, sore."

spinel
  لال، لعل   
lâl, la'l (#)

Fr.: spinelle   

A mineral, MgAl2O4, occurring in various colors, used as a gem, the most valuable being red. The famous "Black Prince's Ruby" which forms part of the Crown Jewels of England, is, in fact, a red spinel. Spinel has often been confounded with → ruby. The most famous source of spinel is the historic region of Badakhshan (today northeastern Afghanistan and southeastern Tajikistan). The Badakhshan mines were mentioned by Persian writers as early as the 10th century. According to a Persian tradition, these mines were first disclosed when the mountain was broken open by an earthquake.

From Fr. spinelle, from It. spinella of unknown origin.  

Lâl, la'l "spinel; red," originally "red" (cf. Tabari âl "red"); cf. Av. raoidita- "red, reddish;" Skt. rudhirá- "red, bloody;" L. ruber "red;" Gk. erythros "red;" akin to E. → red.

spinning top
  فرموک، فرفره   
farmuk (#), ferferé (#)

Fr.: toupie   

A toy that with a quick or vigorous twist spins around its symmetry axis and balances on a point. Suppose a top is perfectly fashioned so that its → rotation axis passes through its → center of mass. If it is spun carefully such that it remains perfectly upright while rotating, it will spin at a steady → angular velocity almost indefinitely in the absence of → friction. Rotation creates an → angular momentum which is directed upward along the rotation axis, opposite to the → gravity vector. However, a slight mismatch between the rotation axis and the center of mass causes gravity to exert a → torque on the top due to its weight, acting through the center of mass. The torque gives rise to a time rate of change of angular momentum, so the top experiences → precession about its point of contact. The tip of the angular momentum vector can be perceived as precessing about the → vertical, thus describing the → precessional circle. The top's precession period is given by: Tp = (4π2I)/(mgrTs), where I is the → moment of inertia, m the mass of the top, g gravity, r the distance between the center of mass and the contact point, and Ts is the spinning period of the top. Precession is accompanied by another oscillatory phenomenon, called → nutation. Nutation is less influenced by the gravity torque and is determined by the inertia forces acting on the spinning body.

spin; → -ing; top M.E., from O.E. top, maybe related to Fr. toupie.

Farmuk, ferferé "spinning top" (Dehxodâ), two words of unknown etymology.

spinstar
  چرخاستاره   
carxâsetâré

Fr.: spinstar   

A hypothetical, very rapidly → rotating star formed in the → metal-deficient conditions of the primordial → interstellar medium. The → first stars were probably spinstars, because the lack of metals leads to faster rotation velocities. Indeed → metal-poor stars are more compact than → metal-rich ones. Stars formed from a gas whose → metallicity is below 1/2000 of the → solar metallicity could attain rotation velocities of 500-800 km s-1 (see also → Population III star). Rotation triggers → mixing processes inside the star, leading to the production of important quantities of 14N, 13C, and 22Ne (Maeder & Meynet 2012, and references therein). The production of primary 22Ne has an important impact on the → s-process  → nucleosynthesis in spinstars compared to non-rotating stars. This increases by orders of magnitude the s-process → yields of → heavy elements. Spinstars would therefore have strongly influenced the properties and appearance of the first galaxies that formed in the → Universe (See G. Meynet et al. 2009, arXiv:0709.2275; C. Chiappini, 2013, Astron. Nachr. /AN 334, No. 6, 595 and references therein).

spin; → star.

spintronics
  اسپین‌ترونیک   
espintronik

Fr.: spintronique   

A new area of science and technology which exploits the intrinsic → spin of electrons and its associated → magnetic moment, in addition to its fundamental electronic charge, in solid-state devices. In brief, spin-based electronics. For example, information could be transported or stored through the spin-up or spin-down states of electrons. Spintronics techniques are capable of much higher speed while requiring less power than the conventional method of using electron charges to represent data. The first use of spintronics was in the late 1980s with the development of → giant magnetoresistance (GMR) read heads for disk drives

Short for → spin + → electronics.

spiral
  مارپیچ   
marpic (#)

Fr.: spiral   

Running continuously around a fixed point or center while constantly receding from or approaching it.

From M.Fr. spiral, from M.L. spiralis "winding, coiling," from L. spira "coil," from Gk. speira "coil, twist, wreath."

Mârpic, literally "snake coil," from mâr "snake, serpent," → Serpens, + pic, present stem of picidan "to twist, entwine, coil," ultimately Proto-Iranian *paticā-citanai- "to coil;" cf. Av. paitica "inversely; back" and ci- (caē-, caii-) "to heap up, gather" (Nyberg 1974).

spiral arm
  بازوی ِ مارپیچ   
bâzu-ye mârpic

Fr.: bras spiral   

The region in a → spiral galaxy that contains concentrations of → gas, → dust, and → massive stars. Spiral arms are created by → density waves. See also → density wave theory.

spiral; → arm.

spiral galaxy
  کهکشان ِ مارپیچ   
kahkešân-e mârpic

Fr.: galaxie spirale   

A galaxy with a prominent nuclear → bulge and luminous → spiral arms of gas, dust, and young stars that wind out from the nucleus. Masses span the range from 1010 to 1012solar masses.

spiral; → galaxy.

spiral nebula
  میغ ِ مارپیچ   
miq-e mârpic

Fr.: nébuleuse spirale   

An obsolete term used to describe nebular objects with spiral shape before it was understood that they are independent galaxies lying outside our → Milky Way galaxy. Now called → spiral galaxy.

spiral; → nebula.

spiral structure
  ساختار ِ مارپیچ   
sâxtâr-e mârpic

Fr.: structure spirale   

The morphology of a galaxy which displays → spiral arms.

spiral; → structure.

spirit
  مینو   
minu (#)

Fr.: esprit   

The principle of conscious life; the vital principle in humans, animating the body or mediating between body and soul (Dictionary.com).

M.E., from L. spiritus "a breathing, breath; breath of life," related to spirare "to blow, breathe."

Minu "spirit;" Mid.Pers. mênôg "spirit;" Av. mainyu- "mind, mentality, mental force, inspiration," from mān- "to think," → mind.

spiritual
  مینویی، مینوییگ   
minuyi, minuyig

Fr.: spirituel   

Of, pertaining to, or consisting of → spirit.

spirit; → -al.

spirituality
  مینوییگی   
minuyigi

Fr.: spiritualité   

The quality or fact of being → spiritual.

spiritual; → -ity..

Spite plateau
  تختال ِ اسپیت   
taxtâl-e Spite

Fr.: plateau des Spite   

The observation that the abundance of → lithium (7Li) in metal-poor stars is constant regardless of the → effective temperature (> 5500 K) and the → metallicity ([Fe/H] < -2). The Spite plateau is currently interpreted as evidence that the Li observed in → halo population stars is → primordial. Since its discovery, the Spite plateau has been subject to numerous investigations, increasing the number of stars with Li measurements and extending the sample to include ever lower metallicities. Important issues are the existence or not of a significant scatter along the plateau, and the existence or not of atomic diffusion and mixing with deeper stellar zones where Li can be burnt, producing an offset with respect to the → Big Bang → nucleosynthesis abundance. Several recent studies have shown that the Spite plateau exhibits very little, if any, dispersion. There is, however, a discrepancy between recent results and that derived from Big Bang nucleosynthesis, based on the cosmological parameters constrained by the → WMAP measurements.

Named after François and Monique Spite, French astronomers, Paris Observatory, who first discovered this relation (1982, A&A 115, 357); → plateau.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer aga air Alf Alg alk Alp alt alu amm ana And ang ani ano ant ant Ap apo app app Aqu Arc arg arr asc ass ast ast asy atm ato att aur aut axi B-m bad Bal bar bar Bay Bed ber Bet bif bim bin bio bis bla ble blu Bod Bol bor bou Bra Bre bro bul C-t Cal Cam can car Car Cas cat cav cel cen cer Cha cha Cha che chl Cir cir cir Cla cli clo clu co- coc coh col col col Com com com com com com com com Com con 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 Dan dat Dav de- Deb dec dec dee def deg del Den den der det deu dew dic dif dif dil Dip dir dis dis dis dis dis diu dod Dop dou Dra dua dus dwa dyn DZ Ear ecc eco edi EHB Ein ela ele ele ele ele ell eme emp end Eng ent epi equ equ era ESP eth Eur evi exa exc exe exi exp exp ext ext ext fac fal far fec Fer fer fie fin fir fis fla Flo flu fog for for Fou fra fre fre Fro fun G s Gal gal gal Gar gau geg gen geo geo geo ger gla gly gra gra gra gra gra Gre gro GYR Had Hal hap Har HD hea hel hel Hen Her hex hig Hil hol Hoo hor hou Hub hum hyb hyd hyd hyp hys ide ign ima imp imp in- inc Ind ind ine inf inf inf ini ins ins ins int int int int Int int int int inv ion iri irr iso iso iso Jea Jor jum K c Kep Ker kin kno lab Lam Lan Lap las lat Le lef len lev lig lig lin lin lin liq Lit loc log lon lou LS lun lun Lym M s Mag mag mag mag mag mag maj man Mar mas mas mat May mea mec mel mer mes met met met mic mid mil Min Mir mix mod mod mol mon mor mov mul mur mys nan nat nav nec Nep neu New New NGC nob nom non non nor nos nuc nuc num nut obj obl obs occ oct off oli oni ope opp opt opt orb ord org orp osc out ove oxi P-w pal par par par par Pas pat pej per per per per per per pha Phe pho pho pho phy pin pla Pla pla pla pla plu poi pol pol Pol pol por pos pot Poy pre pre pre pre pri pri pri pro pro pro pro pro pro Psa pul pum Q i qua qua qua qua R A rad rad rad rad rad rad Ram Ran rat rea rea rec rec red red ref ref reg rei rel rel rem rep res res res ret rev Rho Rie ril riv rog Ros rot rul S A Sag sam sat sca sca Sch Sco Sec sec sec seg sel sem sen set Sha sha shi sho sid sig sim sin Sir ske sli Smo soc sof sol sol sol sol sou sou spa spe spe Spe spe sph spi Spi spr sta sta sta sta sta ste ste ste Sto str str sub sub sub suc sun sup sup sup sup sur swa syn syn tac tas tel tem ter tes the the the the thi thr tid til tip ton tor tou tra tra tra tra Tri tri tru tsu tur two Typ UHE ult unc uni uni uni upg ura uti val var vec Vel ver Ver vie Vir vis vis vol W-R war wav wav wea Wei wha wid win WN3 Wol wri xen yok zen zij > >>