An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 929
antenna temperature
  دما‌ی ِ آنتن   
damâ-ye ânten

Fr.: température d'antenne   

In radio astronomy, a measure of the power absorbed by the antenna. In an ideal, loss-free radio telescope, the antenna temperature is equal to the brightness temperature if the intensity of the received radiation is constant within the main lobe. → antenna; → temperature.

antenna; → temperature.

Antennae galaxies
  کهکشان‌ها‌ی ِ شاخکی   
kahkešânhâ-ye šâxak

Fr.: galaxies des Antennes   

The pair of colliding galaxies NGC4038 and NGC4039 and the long arcing insect-like "antennae" of luminous matter revealed by optical telescopes. The "antennae" are believed to have been produced by the collision between the galaxies that began about 100 million years ago and is still occurring. The Antennae Galaxies, about 60 million → light-years from Earth, lie in the constellation → Corvus.

Antennae, plural of → antenna; → galaxy.

Kahkešânhâ, plural of kahkešângalaxy; šâxak "insect antenna," from šâx "horn" (Mid.Pers šâk, cf. Skt. sakha- "a branch, a limb," Arm. cax, Lit. šaka, O.S. soxa, PIE *kakhâ "branch") + -ak suffix denoting relation, affinity, similarity (as in dastak, pos(tak, pas(mak, xarak, nâxonak, mus(ak, eynak);

anthropic principle
  پروز ِ انسان-هستی   
parvaz-e ensân-hasti

Fr.: principe anthropique   

The idea that the existence of → life and, in particular, our presence as → intelligent  → observers, → constrains the nature of the → Universe. It is an attempt to explain the observed fact that the → fundamental constants of nature are just right or fine-tuned to allow the Universe and life to exist. This is not however a "principle." See also → weak anthropic principle, → strong anthropic principle. Compare → Copernican principle.

Anthropic, from Gk. anthropikos "human," from anthropos "human being, man," → anthropo-; → principle.

Parvaz, → principle; ensân-hasti, from ensân, → anthropo-, + Mod.Pers. hasti "existence, being," Mid.Pers. astih, O.Pers. astiy; Av. asti "is," O.Pers./Av. root ah- "to be;" cf. Skt. as-; Gk. esti; L. est; PIE *es-.

ensân- (#)

Fr.: anthropo-   

A prefix with the meaning of "pertaining to man or human beings." Before a vowel, anthrop-. See also → man, → human. → anthropic principle.

Frpm Gk. anthropos "man, human being," from aner "man" (as opposed to a woman, a god, or a boy), from PIE *hner "man;" cf. Pers. nar "male," Skt. nara-, Welsh ner "man."

Ensân-, from ensân "mankind," loan from Ar. insân.

anti-, ant-
pâd- (#)

Fr.: anti-, ant-   

Prefix meaning "against, opposite of;" e.g. in → anticenter; → anticorrelation; → anticyclone; → antiparticle.

L. anti- from Gk. anti "against, opposite, instead of," from PIE *anti "against".

Pâd- "agaist, contrary to," from Mid.Pers. pât- "to, at, for, in," from O.Pers. paity "agaist, back, opposite to, toward, face to face, in front of;" Av. paiti; cf. Skt. práti "toward, against, again, back, in return, opposite;" Pali pati-; Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti.


Fr.: antibaryon   

The → antiparticle of a → baryon.

anti-; → baryon.


Fr.: anticentre   

The point in the → Galactic plane that lies directly opposite the → Galactic center. It lies in → Auriga at approximately R.A. 5h 46m, Dec. +28° 56'; the nearest bright star to it is → Alnath in → Taurus.

Anticenter, from → anti- + → center.

Pâdmarkaz, from pâd-, → anti-, + markaz, → center.

  پاد‌افسر، شکوه   
pâdafsar, šokuh

Fr.: gloire   

Meteorology: Small, faintly colored rings of light surrounding the → antisolar point, seen when looking down at a water cloud. Same as glory.

Anticorona, from → anti- + → corona.

Pâdafsar, from pâd-, → anti- + afsar "corona."
Šokuh "glory."


Fr.: anticorrelation   

Statistics: The correlation coefficient of two random variables X and Y is in general defined as the ratio of the Cov(X,Y) to the two standard deviations of X and Y. It varies between 1 and -1 corresponding to complete correlation or anticorrelation.

Anticorrelation, from → anti- + → correlation.

Pâdhambâzâneš, from pâd-, → anti-, + hambâzâneš, → correlation.

anticrepuscular rays
  پرتوهای ِ پاد نیمتابی   
partowhâ-ye pâdnimtâbi

Fr.: rayons anticrépusculaires   

Rays of → sunlight that appear to converge at the → antisolar point. Like → crepuscular rays, they are parallel beams of sunlight from holes in the clouds, and their apparently odd directions are a perspective effect.

anti-; → crepuscular rays.


Fr.: anticyclone   

Meteo.: A weather phenomenon associated with atmospheric high pressure. In the northern hemisphere an anticyclone rotates in the clockwise direction. The rotation is caused by the movement of colder higher pressure air that is moving away from the poles toward the equator being affected by the rotation of the Earth.

anti-; → cyclone.

  کریای ِ نخستین   
karyâ-ye noxostin

Fr.: primitive   

The function F(x) is called the antiderivative of the function f(x) on the interval [a,b] if at all points of this interval F'(x) = f(x). Same as primitive.

anti- + → derivative.

Karyâ, → function; noxostin "primitive," → first.


Fr.: antiferromagnétisme   

A property possessed by some → metals, → alloys, and salts of transition elements in which there is a lack of → magnetic moment due to the antiparallel or spiral arrangement of atomic → magnetic moments.

anti- + → ferromagnetism.


Fr.: antihydrogène   

An atom made from an → antiproton and a → positron. In 2010 a research collaboration at CERN combined decelerated antiprotons with positrons to produce antihydrogen atoms. They managed 38 times to confine single antihydrogen atoms in a magnetic trap for more than 170 milliseconds (Andersen et al. 2010, Nature, 17 Nov.).

anti- + → hydrogen.

Antikythera mechanism
  ساز-و-کار ِ آنتیکوترا   
sâzokâr-e Antikythera

Fr.: machine d'Anticythère   

A unique Greek geared device, constructed around the end of the second century BC to display the movement of the Sun, the Moon, and possibly the planets around the Earth, and predict the dates of future eclipses. It measures about 32 by 16 by 10 cm and contains at least 30 interlocking gear-wheels, all of them having triangular teeth, from 15 to 223 in number. This device is one of the most stunning artefacts remained from antiquity, revealing an unexpected degree of technical creativity for the period. Nothing close to its technological sophistication appears again for well over a millennium, when astronomical clocks appear in the medieval Europe. It was discovered in 1901 in a sunken ship just off the coast of Antikythera, an island between Crete and the Greek mainland. Its significance and complexity were not understood until decades later. After lots of study involving several research fields, a copy of the device has recently been constructed. See, e.g., Freeth et al. 2006, Nature 444, 587.

Named after the Greek island in the Ionia Sea from which the fragments of the device were discovered in 1901 by sponge divers, who found a sunken Roman ship. Several pieces of evidence indicate that the Roman ship carrying the device wrecked sometime shortly after 85 BC. The ship also contained an enormous booty of bronzes, glassware, jewelry and pottery; → mechanism.

pâdmâddé (#)

Fr.: antimatière   

Matter composed entirely of → antiparticles. See also → antihydrogen.

Antimatter from Gk. → anti- "opposite, opposing, against" + → matter.

Pâdmâddé from pâd-, → anti-, + mâddé, → matter.

ântimuân (#)

Fr.: antimoine   

A silver white metallic element of a flaky nature, extremely brittle, occurring in nature free or combined, symbol Sb. → Atomic number 51; → atomic weight 121.75; → meting point 630.74°C; → boiling point 1,750°C; → specific gravity (metallic form) 6.69 at 20°C. Antimony is recognized in compounds from antiquity, and as a metal since the 17th century. The minerals stibnite (Sb2S3) and stibine (SbH3) are two of a multitude of mineral species which were known in the ancient world. Antimony is a poor conductor of heat and electricity. It greatly increases the hardness of metals with which it makes → alloys. Its various unstable isotopes have a half-life of 16 min (Sb120) to 2.7 years (Sb125).

From M.E. antimonie, from M.L. antimonium, an alchemist's term, of obscure origin, maybe a Latinization of Gk. stimmi or stibi, probably ultimately from Egyptian stm "cosmetic powder" used to paint the eyelids. The chemical symbol, Sb, comes from the original name, stibium, which is derived from Gk. stibi for "mark," since it was used for blackening eyebrows and eyelashes. The name was changed from stibium to antimonium to antimony.

Ântimuân, loan from Fr. antimoine.


Fr.: antineutrino   

The → antiparticle counterpart of the → neutrino.

anti-; → neutrino.


Fr.: antineutron   

The → antiparticle of the → neutron. It has the same mass, → spin, and → electric charge (zero) as the neutron but has opposite → baryon number (+1 for neutron, -1 for the antineutron). This is because the antineutron is composed of → antiquarks, while neutrons are composed of → quarks. The antineutron consists of one up antiquark and two down antiquarks.

anti-; → neutron.

  پاد-گره، شکم   
pâdgereh (#), šekam (#)

Fr.: anti-nœud   

The position of maximum → amplitude midway between two adjacent → nodes in a → standing wave.

anti-; → node.

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