An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 458
hanjaré (#)

Fr.: larynge   

A muscular and cartilaginous structure lined with mucous membrane at the upper part of the → trachea in humans, in which the → vocal cords are located (

From M.Fr. larynx, from M.L. from Gk. larynx (genitive laryngos) "the upper windpipe," probably from laimos "throat," influenced by pharynx "throat, windpipe."

Hanjaré, from Ar. Hanjarah.

leyzer (#)

Fr.: laser   

1) A device that generates an intense directional beam of → monochromatic and → coherent light by exciting atoms to a higher energy level and causing them to radiate their energy in phase. The high degree of collimation arises from the fact that excited atoms are are situated in a cavity bounded by two parallel front and back mirrors. A first photon stimulates an atom which emits a second photon, and so on thanks to the mirrors. The resulting photons are all identical. They have the same energy which gives them the same color and a unique direction. The first working laser, a pulsed ruby device, was developed by T. Maiman in 1959. See also → gas laser, → stimulated emission; → maser.
2) The light produced in this way.

Acronym for light amplification by stimulated emission of radiation, on pattern of → maser.

laser cooling technique
  تشنیک ِ سردش ِ لیزری   
tašnik-e sardeš-e leyzeri

Fr.: technique de refroidissement par laser   

A technique that uses a suitable arrangement of → laser beams and magnetic fields to capture → cesium (133Cs) atoms from a thermal vapor and slow the motion of the atoms, cooling them to just a few micro-kelvins above the → absolute zero. The technique allows trapping some 107 cesium atoms in a cloud a few millimeters in diameter in a few tenths of a second. At a temperature of 2 μK, the average thermal velocity of the cesium atoms is of the order of 1 cm s-1, so they stay together for a relatively long time. The laser cooling technique is the key tool which enabled the operation of an → atomic fountain clock.

laser; → cooling; → technique.

Laser Interferometer Gravitational-Wave Observatory (LIGO)
  نپاهشگاه ِ موجهای ِ گرانشی با اندرزنش‌سنجی ِ لیزری   
nepâhešgâh-e mowjhâ-ye gerâneši bâ andarzaneš-sanji-ye leyzeri

Fr.: Observatoire d'ondes gravitationnelles par interférométrie laser   

A facility dedicated to the detection and measurement of cosmic → gravitational waves. It consists of two widely separated installations, or detectors, within the United States, operated in unison as a single observatory. One installation is located in Hanford (Washington) and the other in Livingston (Louisiana), 3,000 km apart. Funded by the National Science Foundation (NSF), LIGO was designed and constructed by a team of scientists from the California Institute of Technology, the Massachusetts Institute of Technology, and by industrial contractors. Construction of the facilities was completed in 1999. Initial operation of the detectors began in 2001. Each LIGO detector beams laser light down arms 4 km long, which are arranged in the shape of an "L." If a gravitational wave passes through the detector system, the distance traveled by the laser beam changes by a minuscule amount -- less than one-thousandth of the size of an atomic nucleus (10-18 m). Still, LIGO should be able to pick this difference up. LIGO directly detected gravitational waves for the first time from a → binary black hole merger (GW150914) on September 14, 2015 (Abbott et al., 2016, Phys. Rev. Lett. 116, 061102).

laser; → interferometer; → gravitational; → wave; → observatory.

Laser Interferometer Space Antenna (LISA)
  آنتن ِ فضایی ِ اندرزنش‌سنج ِ لیزری   
ânten-e fezâyi-e andarzanešsanj-e leyzeri

Fr.: Observatoire d'ondes gravitationnelles par interférométrie laser   

A collaborative project between → NASA and → ESA to develop and operate a space-based gravitational wave detector sensitive at frequencies between 0.03 mHz and 0.1 Hz. LISA detects gravitational-wave induced strains in → space-time by measuring changes of the separation between fiducial masses in three spacecraft 5 million km apart. Ultimately, NASA and ESA decided in 2011 not to proceed with the mission. LISA was not the highest ranked mission in the 2010 Decadal Survey and funding constraints prevented NASA from proceeding with multiple large missions ( → LISA pathfinder.

laser; → interferometer; → space; → antenna.

vâpasin (#)

Fr.: dernier   

Occurring or coming after all others, as in time, order, or place. → last contact, → last quarter

Last, from O.E. latost (adj.) and lætest (adv.), superlative of læt (adj.) and late (adv.); cognate with O.Fris. lest, Du. laatst, O.H.G. laggost, Ger. letzt.

Vâpasin, from vâ-, as intensive prefix, → de-, + pasin, from pas "after, afterward, behind; finally, at last" (Mid.Pers. pas "behind, before, after;" O.Pers. pasā "after;" Av. pasca "behind (of space); then, afterward (of time);" cf. Skt. pazca "behind, after, later;" L. post "behind, in the rear; after, afterward;" O.C.S. po "behind, after;" Lith. pas "at, by;" PIE base *pos-, *posko-) + -in superlative suffix.

last contact
  پرماس ِ واپسین   
parmâs-e vâpasin

Fr.: dernier contact   

Same as → fourth contact at an eclipse.

last; → contact.

last quarter
  چارک ِ واپسین   
cârak-e vâpasin

Fr.: dernier quartier   

One of the phases of the Moon that appears when it is 90 degrees west of the Sun. Approximately one week after a full moon, when half of the Moon's disk is illuminated by the Sun. → first quarter.

last; → quarter.

last scattering
  واپسین پراکنش   
vâpasin parâkaneš

Fr.: dernière diffusion   

The epoch in the early evolution of the Universe when matter and photons decoupled. Once atoms formed, light and matter stopped constantly interacting with one another, and photons were able to travel freely. As a result, the Universe became transparent. Light from this period is observed today as the → cosmic microwave background radiation. Same as → decoupling era and → recombination era.

last; → scattering.

last scattering surface
  رویه‌ی ِ واپسین پراکنش   
ruye-ye vâpasin parâkaneš

Fr.: surface de dernière diffusion   

The set of locations in space corresponding to the → last scattering epoch in the early Universe. It is a spherical surface around the present-day observer from which the → cosmic microwave background radiation appears to emanate.

last; → scattering; → surface.


Fr.: dernier né   

Last in order of birth; youngest.

last; → born.

Demâzâ, from Lori, Laki demâzâ, from demâ "last, end, back," related to dom, → tail, + contraction of zâd, → born.

  فرجامین، دیر   
farjamin (#), dir (#)

Fr.: tardif; tard   

Belonging to an advanced stage or period in the development of something, happening or arriving after an expected or arranged time; not on time, beyond usual time.

M.E., from O.E. læt "slow, late;" cf. Ger. lass "slothful;" O.N. latr, Goth. lats "slow, lazy;" L. lassus "tired, faint;" Gk. ledein "to be weary."

Farjâmin "belonging to the end; concluding," from farjâm "end; conclusion," from Mid.Pers. farzâm "end; conclusion," farzâftan "to finish, to be perfect;" from Proto-Iranian *fra-gam- "to send; to finish" (cf. O.Pers. prāgama- "to go forth"), from *gam- "to go; to come;" cf. Av. gam- "to come; to go," jamaiti "goes;" O.Pers. gam- "to come; to go;" Mod./Mid.Pers. gâm "step, pace," âmadan "to come;" cf. Skt. gamati "goes;" Gk. bainein "to go, walk, step;" L. venire "to come;" Tocharian A käm- "to come;" O.H.G. queman "to come;" E. come; PIE root *gwem- "to go, come."
Dir "late; tardily, slowly; a long while; old, antique," from Mid.Pers. dêr, variants dagr, drâz "long" (Mod.Pers. derâz "long," variant Laki, Kurdi derež); O.Pers. darga- "long;" Av. darəga-, darəγa- "long," drājištəm "longest;" cf. Skt. dirghá- "long (in space and time);" L. longus "long;" Gk. dolikhos "elongated;" O.H.G., Ger. lang; Goth. laggs "long;" PIE base *dlonghos- "long."

Late Heavy Bombardment (LHB)
  بمباران ِ سنگین ِ دیر   
bombârân-e sangin-e dir

Fr.: Grand Bombardement Tardif   

A cataclysmic event in the history of the → solar system, estimated to have occurred 3.9 billion years ago (about 600 million years after the formation of the → terrestrial planets) during which → asteroid and → comet impacts with Earth were some 20,000 times more frequent than today. It is estimated that during this period the terrestrial planets were bombarded with an object 1 km in size every 20 years. This hypothetical event lasted 50 to 150 million years. Several explanations have been put forward, among which the occurrence of an instability in the outer solar system which caused → orbital migration of small bodies from the → Kuiper belt inward.

late, with respect to the formation time of the planets; → heavy; bombardment, noun from bombard, from Fr. bombarder, from bombarde "mortar, catapult" from bombe, from It. bomba, probably from L. bombus "a booming sound," from Gk. bombos "deep and hollow sound."

late helium flash
  درخش ِ هلیوم ِ فرجامین   
deraxš-e heliom-e farjâmin

Fr.: flash de helium tardif   

A → helium flash event that occurs during the → post-AGB phase. Some of the central stars of planetary nebulae (→ CSPN) experience a final → thermal pulse after having achieved a → white dwarf configuration and begun their descent along a → white dwarf cooling track of nearly constant radius. During such a pulse, most of the hydrogen remaining in the star at pulse onset is incorporated into the helium-burning convective shell and completely burned. Following the pulse, the star swells briefly to → red giant dimensions (Iben et al. 1983; ApJ 264, 605).

late; → helium; → flash.

late thermal pulse
  تپه‌ی ِ گرمای ِ دیر   
tape-ye garmâyi-ye dir

Fr.: flash de l'hélium tardif   

In evolutionary models of → low-mass and → intermediate-mass stars, the occurrence of a → helium shell flash on the → horizontal branch of the → post-AGB track, while → hydrogen shell burning is still going on.

late; → thermal; → pulse.

late-type galaxy (LTG)
  کهکشان ِ گونه‌ی ِ فرجامین   
kahkešân-e gune-ye farjâmin

Fr.: galaxie de type tardif   

In the → Hubble classification, a galaxy on the left part of the → Hubble sequence. See also → early-type galaxy.

late; → type; → galaxy.

late-type star
  ستاره‌ی ِ گونه‌ی ِ فرجامین   
setâre-ye gune-ye farjâmin

Fr.: étoile de type tardif   

A star of → spectral type K, M, S, or C, with a surface temperature lower than that of the Sun. → early-type star. See also → spectral classification.

late; → type; → star.

nahân (#)

Fr.: latent   

Present but not visible, apparent, or actualized; existing as potential ( → latent heat.

From L. latentem (nominative latens), pr.p. of latere "to lie hidden."

Nahân "concealed, hid; clandestine;" Mid.Pers. nihân "secrecy, a secret place, a hiding place," nihânik "concealed;" Av. niδāti- "deposing, deposit."

latent heat
  گرمای ِ نهان   
garmâ-ye nahân (#)

Fr.: chaleur latente   

The amount of → thermal energy that is absorbed or released by a unit amount of a substance in the process of a phase change under conditions of constant pressure and temperature.

latent; → heat.

  کناری، پهلویی، بری   
kenâri, pahluyi, bari

Fr.: latéral   

Of or relating to the side; situated at, proceeding from, or directed to a side (

M.E., from O.Fr. latéral and directly from L. lateralis "belonging to the side," from latus "the side, flank; lateral surface."

Kenâri, relating to kenâr, → side.

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