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: 13116 Search : far
Jordan matrix
  ماتریس ِ ژوردان   
mâtris-e Jordan (#)

Fr.: matrice de Jordan   

A square matrix with a constant value λ (nonzero) along the diagonal, 1's on the superdiagonal, and all other elements 0.

Named after Marie Ennemond Camille Jordan (1838-1922), French mathematician who pioneered group theory, wrote on the theory of linear differential equations, and on the theory of functions, which he applied to the curve which bears his name. → matrix.

Jordan-Brans-Dicke theory
  نگره‌ی ِ یوردان-برانز-دایک   
negare-ye Jordan-Brans-Dicke

Fr.: théorie de Jordan-Brans-Dicke   

A relativistic theory of gravitation which involves a → scalar field in addition to the → metric (→ tensor field) used in rarr; general relativity. It obeys the → equivalence principle, but tries at the same time to comply with → Mach's principle owing to possible spatial and temporal variations of the → gravitational constant, which is inversely proportional to the scalar field. The theory uses a new dimensionless parameter to determine the discrepancy between its predictions and those of general relativity. So far there is no firm indication of its validity. Same as → scalar-tensor theory.

Named after the creators, Carl Brans (1935-) and Robert Dicke (1916-1997), who presented the theory in 1961, based on the initial work of Pascual Jordan (1902-1980); → theory.

Josephson effect
  ا ُسکر ِ جوزفسون   
oskar-e Josephson

Fr.: effet Josephson   

A quantum mechanical → tunnel effect allowing the flow of a continuous current across two weakly coupled → superconductors which are separated by a very thin insulating barrier.

Named after the British physicist Brian David Josephson, who predicted the existence of the effect in 1962; → effect.

Josephson junction
  جوهه‌ی ِ جوزفسون   
juhe-ye Josephson (#)

Fr.: jonction Josephson   

A type of electronic circuit involving → Josephson effect, capable of switching at very high speeds when operated at temperatures approaching → absolute zero.

Josephson effect; → junction.

joule (J)
  ژول   
joule (#)

Fr.: joule   

A unit of → energy in the → International System of Units equal to the → work performed by one → newton over a distance of 1 → meter. 1 J is equivalent to 107 ergs = 1 Watt second = 2.78 × 10-7 kWh = 0.2389 calories = 6.24 × 1018 eV.

In honor of the English physicist James Prescott Joule (1818-1889), who established that the various forms of energy (mechanical, electrical, and heat) are basically the same and can be changed, one into another.

Joule is in Pers. pronounced as žul, loaned from the Fr. rendering of the E. name.

Joule effect
  اسکر ِ ژول   
oskar-e Joule

Fr.: effet Joule   

A → conductor becomes heated by the passage of an electric current through it due to the → resistance of the conductor. Same as → Ohmic dissipation.

joule; → effect.

Joule's constant
  پایای ِ ژول   
pâyâ-ye Joule (#)

Fr.: constante de Joule   

The proportional relationship of mechanical energy to thermal energy, equal to 4.184 joules per calorie. Also called mechanical equivalent of heat.

joule; → constant.

Joule-Thomson effect
  اسکر ِ ژول-تامسون   
oskar-e Joule-Thomson

Fr.: effet Joule-Thomson   

The change in the temperature of a gas in the → throttling process.

Joule; → Thomson; → effect.

Jovian
  هرمزی   
Hormozi

Fr.: jovien   

Of or pertaining to the → planet  → Jupiter.

From L. Jovius "Jupiter," Roman god of the sky, cognate with deus "god;" Gk. Zeus "supreme god;" Pers. div "devil, demon" (Mid.Pers. dêw; O.Pers. daiva- "evil god, demon;" Av. daēva- "evil spirit, false god;" Skt. deva-; PIE base *deiwos "god," from *dei- "to gleam, to shine").

Hormozi, related to Hormoz, → Jupiter.

Jovian planet
  سیاره‌ی ِ هرمزی   
sayyâre-ye Hormozi

Fr.: planète jovienne   

A planet that does not have a well-defined → solid  → crust, such as any of the four Solar System outer, gaseous planets: → Jupiter, → Saturn, → Uranus, and → Neptune.

Jovian; → planet.

Joy's law
  قانون ِ جوی   
qânun-e Joy

Fr.: loi de Joy   

Sunspot pairs or groups are tilted with the → leader spots closer to the equator than the → follower spots. The tilt of bipolar sunspot pairs increases with latitude.

Alfred Harrison Joy (1882-1973), an American astronomer; → law.

judge
  ۱) دادرس، داور؛ ۲) داوری کردن   
1) dâdras (#), dâvar; 2) dâvari kardan

Fr.: 1) juge; 2) juger   

1a) A public officer authorized to hear and decide cases in a court of law; a magistrate charged with the administration of justice.
1b) A person qualified to pass a critical judgment.
2a) To pass legal judgment on; pass sentence on (a person).
2b) to form a judgment or opinion of; decide upon critically (Dictionary.com).

M.E. jugen, from Anglo-Fr. juger, O.Fr. jugier "to form an opinion about; make a decision," also "to try and pronounce sentence upon (someone) in a court," from Anglo-Fr juger, O.Fr. jugier "to judge, pronounce judgment; pass an opinion on," from L. iudicare "to judge, to examine officially; form an opinion upon; pronounce judgment," from iudicem "a judge," a compound of ius "right, law," → just, + root of dicere "to say."

Dâdras "justice administrator," from dâd, → justice, + ras present stem and agent noun of rasidan "to attain, to arrive, to mature," → access.

judgment
  داوری   
dâvari (#)

Fr.: jugement   

11 An act or instance of judging.
2) The ability to judge, make a decision, or form an opinion objectively, authoritatively, and wisely, especially in matters affecting action; good sense (Dictionary.com).

judge; → -ment.

judicial
  داورانه، داوریک   
dâvarâné, dâvarik

Fr.: judiciaire   

1) Pertaining to judgment in courts of justice or to the administration of justice: judicial proceedings; the judicial system.
2) Pertaining to courts of law or to judges; judiciary: judicial functions.
3) Of or relating to a judge; proper to the character of a judge; judgelike: judicial gravity.
4) Inclined to make or give judgments; critical; discriminating: a judicial mind.
5) Decreed, sanctioned, or enforced by a court (Dictionary.com).

From L. iudicalis "of or belonging to a court of justice," from iudicium "judgment, decision," from iudicem, → judge.

Dâvarâné, dâvarik, of or relating to dâvari, → judgment.

Julian calendar
  گاهشمار ِ یولیانی   
gâhšomâr-e Yuliyâni (#)

Fr.: calendrier julien   

A → solar calendar established by Julius Caesar in 46 B.C. to replace the → Roman calendar. It was inspired by the Egyptian calendar year of 365 days. The astronomer Sosigenes set up the months (January to December) and added an extra day in February every fourth year (→ leap year). This gave an average year of 365.25 days. The Julian calendar remained unchanged for 1,600 years, and was replaced by the → Gregorian calendar to correct its errors. The Roman calendar before the reform was running 80 days out of alignment with the seasons of a true year. Sosigenes fixed the calendar by having 445 days in the year 46 B.C., which brought the seasons in line with the calendar. The year 45 B.C. is known as the first leap year of the Julian calendar. However, Sosigenes' work was misinterpreted and they were placing leap years every 3 years instead of every 4 years.

Julian, adj. of L. Julius.

Julian date (JD)
  گاهداد ِ ژولی‌ین   
gâhdâd-e žulian

Fr.: date julienne   

A timekeeping system which does not have months and years. It is used primarily by astronomers to avoid confusion due to the use of different calendars at different times and places. Julian date is the interval of time in days and fractions of a day since noon 1 January 4713 B.C. (12h Universal Time). For example, January 1, 1970 is JD 2440588. Decimal fractions correspond to fractions of a day so that, for example, an observation made at 15h on June 24, 1962 is given as JD 2437840.13. → modified Julian date (MJD). Note that the "Julius" involved is not Julius Caesar, and this system is unrelated to the Julian calendar, as explained below.

The system was proposed by the French scholar Joseph Justus Scaliger (1540-1609) in 1583 and named after his father, Julius Caesar Scaliger. His choice of starting year was based on the convergence in 4713 B.C. of three calendrical cycles (indication cycle, Metonic cycle, and solar cycle). → date.

Julian day
  روز ِ ژولی‌ین   
ruz-e žulian (#)

Fr.: jour julien   

Same as → Julian date.

Julian date; → day.

Julian epoch
  زیمه‌ی ِ یولیانی   
zime-ye Yuliyâni

Fr.: époch julienne   

A way of specifying the date as a year with a decimal based on the Julian year of 365.25 days and the Barycentric Dynamical Time (TDB). The standard epoch currently in use is J2000.0, which corresponds to January 1, 2000 12:00 Terrestrial Time.

Julian calendar; → epoch.

Julian year
  سال ِ یولیانی   
sâl-e yuliyâni (#)

Fr.: année julienne   

A period of 365.25 days adopted in the Julian calendar for the length of the year.

Julian calendar; &rarr ;year.

jump
  جهش   
jaheš (#)

Fr.: saut   

A point of discontinuity in a function or a derivative of a function.

Etymology unclear, probably akin to L.G. gumpen "to jump."

Jaheš, verbal noun of jahidan, jastan "to jump, to leap," from Mid.Pers. jastan, jahidan "to jump," figuratively "to happen, occur;" Av. yaēš-, yas- "to boil;" cf. Skt. yas-, yásyati "to boil, to heat; to make effort."

<< < -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 > >>