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: 491
blackbody spectrum
  بیناب ِ سیه‌جسم   
binâb-e siyah-jesm (#)

Fr.: spectre de corps noir   

A curve displaying → blackbody radiation intensity versus the wavelength for a given temperature, according to → Planck's blackbody formula. It is an asymmetrical curve with a sharp rise on the short wavelength side and a much more gradually sloping long-wavelength tale. Same as → Planck spectrum.

blackbody; → spectrum.

blackbody temperature
  دما‌ی ِ سیه‌جسم   
damâ-ye siyah-jesm (#)

Fr.: température de corps noir   

The temperature at which a blackbody would emit the same radiation per unit area as that emitted by a given body at a given temperature.

blackbody; → temperature.

blackout
  خاموشزار   
xâmušzâr

Fr.: panne d'électricité, black-out   

1) A period of darkness caused by a complete loss of electrical power in a particular area.
2) The extinguishing of all artificial light enforced as a precaution against air raids.

black; → out.

Xâmušzâr, târikzâr from xâmuš "extinguished," → extinction, târik, → dark, + -zâr suffix denoting profusion and abundance, sometimes with negative nuance, such as in šurezâr "unfertile, salty ground; nitrous earth," xoškzâr "arid land far from water," lajanzâr "field of black mud, marsh," kârzâr "a field of battle; conflict; engagement."

Blandford-Zanjek process
  فراروند ِ بلندفورد-زنجک   
farâravand-e Blandford-Zanjek

Fr.: processus de Blandford-Zanjek   

A mechanism for the extraction of energy from a rotating → Kerr black hole. It relies on the assumption that the material → accreted by a → black hole would probably be → magnetized and increasingly so as the material gets closer to the → event horizon. Since all black holes of current astrophysical interest are probably accreting from magnetized disks, this has led to suggestions that the Blandford-Znajek process plays a vital role in → active galactic nuclei (AGN) and other accreting black hole systems. The power, P, generated is given by: P = (4π/μ0) B2RS2c, where B is the → magnetic field of the → accretion disk, and RS is the → Schwarzschild radius of the black hole. As an example, for a 108 solar mass black hole with a 1 T magnetic field, the power generated is approximately 2.7 × 1038 W. In perspective, the annual energy consumption of the world is estimated around 5 × 1020 J. The example case presented produces more energy in a single second than the entire globe consumes in a year. While this is a bold claim to make, it is only an example case where not all the energy produced is extractable as useable energy. However, at that point, even a system which is less that < 10-15 % efficient would be sufficient to supply enough energy to power the world for a full year. Of course, the system itself is limited in its lifetime due to the extraction of energy by slowing down the rotation of the black hole. Hence, the system can only exist as long as the black hole has angular momentum, continuing to rotate. At some point, the rotation will cease and the energy source will be unusable (D. Nagasawa, PH240, Stanford University, Fall 2011).

Blandford, R. D., & Znajek, R. L., 1977, MNRAS 179, 433; → process.

blanket
  پتو   
patu (#)

Fr.: couverture   

1) A large piece of thick cloth for use as a bed covering, animal covering, etc, enabling a person or animal to retain natural body heat.
2) Any extended covering or layer (Dictionary.com).
blanketed model, → blanketing, → blanketing effect, → line blanketing, → line-blanketed model, → unblanketed model, → wind blanketing.

From M.E., from O.Fr. blanchet, diminutive of blanc "white; white cloth."

Patu "blanket; a kind of woolen cloth," Kermâni dialect poto "wollen; woolly;" cf. Skt. patta- "cloth, colored or fine cloth."

blanketed model
  مدل ِ پتومند   
model-e patumand

Fr.: modèle à effet de couverture   

line blanketing.

blanketing
  پتومندی   
patumandi

Fr.: effet de couverture   

line blanketing.

blanketing effect
  ا ُسکر ِ پتومندی   
oskar-e patumandi

Fr.: effet de couverture   

line blanketing.

blazar
  بلازار   
blâzâr

Fr.: blazar   

A term specifying → BL Lac objects or → quasars when the → continuum radiation emitted from the active nucleus is highly polarized and very variable.

Blazar, a combination of BL Lac and quasar.

blaze
  بلیز   
beliz

Fr.: flambée; blaze   

1) General: A bright → burst of fire, a flame; a bright or steady light or glare.
2) Optics: The concentration of a limited region of the spectrum into any → order other than the zero order.

O.E. blæse "a torch, flame," from P.Gmc. *blason, from PIE *bhel- "to shine."

Beliz, from Lori beleyz "flame, blaze," Kordi belise "flame, blaze," Mid.Pers. brâh, Av. braz- "to shine, gleam, flash, radiate," cf. Skt. bhâ- "to shine," bhrajate "shines, glitters," O.H.G. beraht "bright," O.E. beorht "bright;" PIE *bhereg- "to shine."

blaze angle
  زاویه‌ی ِ بلیز   
zâviye-ye beliz

Fr.: angle de blaze   

The angle between the operating facet of the grooves and the overall plane of a diffraction grating.

blaze; → angle.

Angâl, zâviyée, → angle; belizblaze.

blaze wavelength
  موج-طول ِ بلیز   
mowjtul-e beliz

Fr.: longueur d'onde de blaze   

The wavelength in a given diffraction order for which the efficiency curve reaches its maximum.

blaze; → wavelength.

Mowjtulwavelength; belizblaze.

blazed grating
  توری ِ بلیزی   
turi-ye belizi

Fr.: réseau échelette   

A → diffraction grating ruled appropriately so that a large proportion of the diffracted light is concentrated into a few, or even a single → order of interference.

Blazed, adj. of → blaze; → grating.

Turi, noun from tur "a net, a fishing net;" belizi adj. from beliz, → blaze.

Blazhko effect
  اسکر ِ بلاژکو   
oskar-e Blazhko

Fr.: effet Blazhko   

A long term, generally irregular modulation of → light curves of a large subclass of → RR Lyrae stars. Most of the modulations occur on the time scale of some 60 periods, although the range extends from some tens to some hundreds of periods. Since its discovery over a hundred years ago, a number of explanations have been proposed for this effect, but its nature is still a matter of investigation. The explanations include: closely spaced pulsation modes, a modal 1 : 2 resonance, an oblique rotator model, a non-radial modal interaction, convective cycles, and nonlinear resonant mode coupling between the 9th overtone and the fundamental mode (see, e.g., R. Buchler and Z. Kolláth 2011, astro-ph/1101.1502).

Named after Sergei N. Blazhko (1870-1956), a Russian astronomer who discovered the effect for the star EW Dra (1907, Astron. Nachr. 175, 325); → effect.

Blazhko star
  ستاره‌ی ِ بلاژکو   
setâre-ye Blazhko

Fr.: étoile à effet Blazhko   

A star showing the → Blazhko effect.

Blazhko effect; → star.

blazing
  بلیزش   
belizeš

Fr.:   

The capcity of a diffraction grating, in certain configurations, to concentrate a large percentage of the incident light into a specific diffraction order.

Blazing, noun from → blaze.

Belizeš, noun from beliz "blaze."

blemish
  آک   
âk

Fr.: défaut   

General: A flaw or defect.
Detectors: Latent imperfections in the photodiodes (pixels) of a solid-state detector.

From O.Fr. blemiss "to turn pale," extended stem of blemir, blesmir "to injure, make pale."

Âk "defect, blemish," Mid.Pers. ak, âk "evil, harm," Av. aka- "bad, wicked;" cf. Skt. aka- "pain , trouble."

blend
  ۱) توهم؛ ۲) توهم شدن   
1) tuham; 2) tuham šodan

Fr.: 1a) blend; 1b) mot-valise; 2) mélanger   

1a) Description of two or more adjacent → spectral lines which are mixed due to insufficient → resolving power of the → spectrograph.
1b) Linguistics: A word which is coined by extracting and combining arbitrary pieces of two or more existing words. Examples include → smog, motel (motor + hotel), brunch (breakfast + lunch), → pulsar, and → shellular. Same as portmanteau.
2) Of two or more → spectral lines, to become merged into one line as a consequence of insufficient instrumental → resolution.

M.E., from O.N. blanda; akin to O.E. blandan "to mix," Lith. blandus "impure, cloudy."

Tuham, from tu "inside" + ham "together," → com-.

blend lines
  خطهای ِ توهم، تانهای ِ ~   
xatthâ-ye tuham, tânhâ-ye ~

Fr.: raies mélangées   

Spectral lines intermingled.

blend; → line.

blind
  کور   
kur (#)

Fr.: aveugle   

Unable to see; sightless.

M.E., from O.E. blind "blind," akin to Du., Ger. blind, O.N. blindr, Goth. blinds "blind."

Kur "blind," variants kul "squint-eyed," kolok, kalek, kelek, kalâž, kâž, kâj, kâc "squint-eyed," Lori, Laki, Kurd. xêl "cross-eyed, squinting;" Mid.Pers. kôr "blind;" akin to O.Irish coll "one-eyed;" M.Irish goll "blind;" Gk. (Hes.) kellas "one-eyed;" Skt. kāná- "blind of one eye;" PIE *kolnos "one-eyed." The Pers. luc "crossed-eyed" may be related to a separate group containing L. lusca, luscus "one-eyed" (Fr. louche "squinting").

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