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 AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit 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 con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>

Number of Results: 13048 Search : far
Milky Way galaxy
  کهکشان ِ راه ِ شیری   
kahkešân-e râh-e širi (#)

Fr.: Voie lactée   

A → spiral galaxy, of which the → solar system is a small part. It is the second largest in our → Local Group of galaxies. The Milky Way is a disk-shaped system, with a diameter of between 80,000 and 100,000 → light-years and a thickness of about 2,000 light-years, containing more than 1011 stars. The stars are divided into two main categories, → Population II stars and → Population I stars.
The core, or nucleus, of the Galaxy is surrounded by an ellipsoidal central → bulge that measures some 15,000 light-years in diameter and about 6,000 light-years in the direction perpendicular to the plane of the disk. Surrounding the bulge and extending in a near spherical distribution above and below the → Galactic plane is the → Galactic halo. The halo contains about 200 → globular clusters and an extremely thinly scattered population of individual stars.
The Sun is located just over half way out from the center to the edge of the disk at a distance of about 25,000 light-years. In common with other stars, the Sun revolves around the → Galactic Center. Its → orbital velocity is about 220 km s-1 and its → orbital period is about 225 million years. Overall, the Galaxy exhibits → differential rotation, that is stars and gas clouds closer to the center have shorter orbital periods than those that are located further out.
The → spiral arms of the Milky Way lie within its disk, where bright → young stars, → H II regions, and → molecular clouds of gas and dust are concentrated into curved "arms" that appear to radiate from the central bulge in a spiral pattern. The Galaxy's spiral pattern consists of several major arms and a number of shorter segments, one of which, the → Orion arm, contains the Sun and the Orion star-forming region.
Near-infrared observations have shown that the stars in the central bulge are arranged in an elongated → galactic bar, about twice as long as it is wide, that is seen nearly end on from the present location of the solar system. The exact center, or nucleus, of the Galaxy coincides with a strong source of radio emission, called → Sagittarius A, that is less than 15 astronomical units in diameter. Observations of the speeds at which clouds of ionized gas are revolving round the → Galactic center imply that several million solar masses of material are concentrated within a region of about one light-year in radius. Since only about half of this mass can be accounted for by stars, it seems likely that the balance (about 2.5 million solar masses) is contained in a central black hole and that accretion onto this black hole is the underlying source of the energy radiated by Sagittarius A.
The Milky Way also has a → dark matter component. The Galactic → rotation curve indicates that there is a large amount of invisible → non-baryonic surrounding the whole Galaxy.

Milky Way; → galaxy.

Milky Way system
  راژمان ِ راه ِ شیری   
râžmân-e râh-e širi

Fr.: Voie lactée   

The huge star system of which the Sun is a member. Same as the Galaxy or the Milky Way galaxy.

Milky Way; → system.

Miller-Urey experiment
  آزمایش ِ میلر-اوری   
âzmâyeš-e Miller-Urey

Fr.: expérience de Miller-Urey   

A chemical experiment conducted in 1953 that aimed at checking Alexander Oparin's and J. B. S. Haldane's hypothesis that under putative conditions present in the atmosphere of the early Earth inorganic molecules would spontaneously form organic molecules. Miller and Urey filled a sterile flask with a mixture of water, ammonia, methane, and hydrogen. The mixture was heated to evaporate water to produce water vapor. High-voltage electric sparks were passed through the mixture to simulate lightning. After a week, contents were analyzed. Amino acids, the building blocks for proteins, were found.

Named after Stanley L. Miller (1930-2007) and Harold C. Urey (1893-1981); → experiment.

milli-
  میلی-   
mili- (#)

Fr.: milli-   

Prefix meaning one thousandth (10-3).

From Fr., from L. mille "thiusand."

Mili-, loan from Fr.

millibar
  میلی‌بار   
milibâr (#)

Fr.: millibar   

One thousandth of a bar; a unit of atmospheric pressure. The average atmospheric pressure at sea level is 1.01325 bars or 1013.25 mb.

milli-; → bar.

Millikan's oil-drop experiment
  آزمایش ِ میلیکن   
âzmâyeš-e Millikan (#)

Fr.: expérience de Millikan   

A precision experiment for measuring the → electron charge. By studying the falling speed of small charged droplets in the gravitational field of the Earth subjected to an adjustable electric field, Millikan (1909) was able to demonstrate conclusively the discrete nature of electric charge, and moreover measure the charge of an individual electron.

Robert Andrews Millikan (1868-1953); → experiment.

millimeter wave
  موج ِ میلی‌متری   
mowj-e milimetri (#)

Fr.: onde millimétrique   

Microwaves with wavelengths between 1 and 10 millimeter, corresponding to frequencies between 300 GHz to 30 GHz. → millimeter-wave astronomy.

milli-; → meter; → wave.

millimeter-wave astronomy
  اخترشناسی ِ موج‌های ِ میلی‌متری   
axtaršenâsi-ye mowjhâ-ye milimetri (#)

Fr.: astronomie millimétrique   

That part of radio astronomy which uses electromagnetic waves in the range 1-10 millimeter to study various components of the Universe, in particular the chemistry of interstellar matter.

millimeter wave; → astronomy.

million
  میلیون   
milyon (#)

Fr.: million   

A thousand thousand (106).

O.Fr. million, from It. millione, literally "a great thousand," augmentative of mille "thousand," from L. mille.

Milyon, Loan from Fr.

millisecond pulsar
  پولسار ِ میلی‌ثانیه، تپار ِ ~   
pulsâr-e milisâniyé (#), tapâr-e ~ (#)

Fr.: pulsar milliseconde   

A type of pulsar that spins around its axis every few thousands of a second. The prototype 1937+21, discovered in 1982, has a period of 1.56 milliseconds; i.e. it spins more than 600 times per second, the fastest so far found (Backer et al. 1982, Nature 300, 615). These pulsars are distinguished from typical pulsars by the extreme stability of their rotation period. It is thought that they have been rejuvenated by a "spin-up process" involving the accumulation of matter from a companion star. → recycled pulsar.

milli-; → second; → pulsar.

millisievert (mSv)
  میلی-سیورت   
milisievert

Fr.: millisievert   

One thousands of a → sievert.

milli- + → sievert.

Mills cross
  چلیپای ِ میلز   
calipâ-ye Mills

Fr.: croix de Mills   

A design of → radio interferometer made of two lines of → antennae at right angles to one another.

Named after the Australian engineer and astronomer Bernard Yarnton Mills (1920-2011; see R.H. Frater et al. 2013, arXiv:1306.6371); → cross.

Milne cosmological model
  مدل ِ کیهان‌شناختی ِ میلن   
model-e keyhânšenâxti-ye Milne (#)

Fr.: modèle cosmologique de Milne   

Same as → Milne Universe.

Milne Universe; → cosmological; → model.

Milne Universe
  گیتی ِ میلن   
Giti-ye Milne (#)

Fr.: Univers de Milne   

A model of the → Universe which is devoid of matter and where the → space-time is → openM = 0, ΩR = 0, ΩΛ = 0, k = -1). The Universe will expand at a constant rate for ever. See also → empty Universe, → de Sitter Universe.

Put forward by Edward Arthur Milne (1896-1950), a British astrophysicist, who introduced the → cosmological principle; → cosmological; → model.

Milne-Eddington approximation
  نزدینش ِ میلن-ادینگتون   
nazdineš-e Milne-Eddington

Fr.: approximation de Milne-Eddington   

The approximation of a stellar atmosphere with a plane parallel grey atmosphere in radiative equilibrium. It is assumed that a spectral is formed in such a way that the ratio of the line absorption coefficient to the continuous absorption coefficient is constant with depth.

Milne Universe; Arthur Stanley Eddington (1882-1944), prominent British astrophysicist; → approximation.

Mimas
  میماس   
Mimâs (#)

Fr.: Mimas   

The seventh of Saturn's known satellites. It is 392 km in diameter and orbits Saturn at a mean distance of 185,520 km. Mimas' low density (1.17) indicates that it is composed mostly of water ice with only a small amount of rock. The surface is saturated with impact craters, dominated by the largest one measuring 130 km across, known as Herschel. Mimas was discovered in 1789 by Herschel.

In Gk. mythology, Mimas was one of the Gigantes slain by Hephaestus, the god of fire, volcanism, smiths and craftsmen, with barrage of red-hot metal.

mind
  منت   
ment

Fr.: esprit, intelligence, raison   

1) The human faculty to which are ascribed thought, feeling, etc; often regarded as an immaterial part of a person (Dictionary.com).
2) Psychology: The totality of conscious and unconscious → mental processes and activities (Dictionary.com).

M.E. mynd(e), from O.E. gemynd "memory, remembrance; thought, purpose" (cf. Gothic muns "thought," munan "to think;" ON minni "mind;" Ger. Minne (archaic) "love," originally "memory"), from PIE root *men- "think, remember;" cf. Pers. mân, man "mind, thought;" Av. man- "to think;" Skt. matih "thought," Gk. mania "madness," mentio "remembrance;" Lith. mintis "thought, idea," O.C.S. mineti "to believe, think," Russ. pamjat "memory."

Ment, from Mid.Pers. mênitan "to think," Av. mainyeite "he thinks;" O.Pers. man- "to think," maniyaiy "I think," Ardumaniš- (proper noun) "upright-minded," Haxāmaniš- (proper noun, Hellenized Achaemenes, founder of the Achaemenian dynasty) "having the mind of a friend;" Av. mân- "to think," manah- "mind, thinking, thought; purpose, intention," mainyu- "mind, mentality, mental force, inspiration," cf. Sogdian mân "mind;" Skt. man- "to think," mánye "I think," manyate "he thinks," mánas- "intelligence, understanding, conscience;" Gk. mainomai "to be angry," mania "madness," mantis "one who divines, prophet;" L. mens "mind, understanding, reason," memini "I remember," mentio "remembrance;" Lith. mintis "thought, idea;" Goth. muns "thought," munan "to think;" Ger. Minne "love," originally "loving memory;" O.E. gemynd "memory, thinking, intention;" PIE base *men- "to think, mind; spiritual activity."

mineral
  کانی   
kâni (#)

Fr.: minéral   

A naturally occurring inorganic solid. The internal crystalline structure of a mineral is controlled by its elemental composition.

From M.L. minerale "something mined," from neuter of mineralis "pertaining to mines," from minera "mine."

Kâni "mineral," from kân "mine," from kandan "to dig" (Mid.Pers. kandan "to dig;" O.Pers. kan- "to dig," akaniya- "it was dug;" Av. kan- "to dig," uskən- "to dig out" (→ ex- for prefix us-); cf. Skt. khan- "to dig," khanati "he digs").

mini black hole
  مینی‌سیه‌چال   
mini siyahcâl

Fr.: mini corps noir   

A black hole of mass as low as 10-6 gram supposed to have formed in the early Universe following the Big Bang event. Same as primordial black hole.

Mini a shortening of → minimum; → black hole.

minimum
  کمینه   
kaminé (#)

Fr.: minimum   

The least value attained (or attainable) by a function; the opposite of maximum.

From L. minimum "smallest" (thing), neuter of minimus "smallest," superlative of → minor "smaller."

Kaminé, from kamin superlative of kam "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few." Keh "small, little, slender" (related to kâstan, kâhidan "to decrease, lessen, diminish," from Mid.Pers. kâhitan, kâstan, kâhênitan "to decrease, diminish, lessen;" Av. kasu- "small, little;" Proto-Iranian *kas- "to be small, diminish, lessen") + nuance suffix.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit 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 con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>