An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

One of several → input or → output variables of a → fuzzy logic system whose values are → words or → sentences from a natural language, instead of numerical values.

→ linguistic; → variable.

The study of the structure and evolution of → language, including → phonetics, → morphology, syntax, semantics.

From linguistic, from linguistic, from linguist, from L. lingua, → language, + → ics.

Zabânik, from zabân, → language, + -ik, → -ics. Zabânšenâsi, from zabân + šenâsi, → -logy.

1a) A series of names or other items written or printed together in a meaningful grouping or sequence so as to constitute a record.
1b) Computers: A series of records in a file.
2) To set down together in a list; make a list of (Dictionary.com).

From M.E. liste "border, edging, stripe," from O.Fr. liste "border, band, row," also "strip of paper," or from O.It. lista "border, strip of paper, list," both from Germanic sources (compare O.H.G. lista "strip, border, list," O.Norse lista "border."

List, loan from Fr. liste, as above.

1) A list; the act of compiling a list; something listed.
2) Computers: A display or printed list of lines in a program or digital data.

→ list; → -ing.

A → probability distribution in which the natural logarithm (logX) of the → random variable (X) has a → Gaussian distribution.

→ logarithm; → normal distribution.

1) Distance derived by comparison of → observed and → intrinsic luminosities. If an object has a known luminosity L, and the observed flux is S, the luminosity distance is defined by D_L = (L/4πS)^1/2.

2) In cosmology, the → expansion of the Universe results in a diminution of the photon flux and the above equation fails. The reason is that for a homogeneous and isotropic Universe (→ Robertson-Walker metric), the luminosity decreases by a factor (1 + z)⁴. Therefore, the luminosity distance is related to the → angular diameter distance (D_A) by: D_L = (1 + z)².D_A.

→ luminosity; → distance.

1) A civil officer charged with the administration of the law.
2) A minor judicial officer, as a justice of the peace or the judge of a police court, having jurisdiction to try minor criminal cases and to conduct preliminary examinations of persons charged with serious crimes (Dictionary.com).

M.E., from O.Fr. magistrat, from L. magistratus "a magistrate, public functionary," from magistrare "to serve as a magistrate," from magister, "chief, director," → master.

Dâdyâr, from dâd, → justice, + yâr, "assistant, helper," → gravity assist.

A selection effect in observational astronomy. If a sample of objects (galaxies, quasars, stars, etc.) is flux-limited, then the observer will see an increase in average luminosity with distance, because the less luminous sources at large distances will not be detected.

Named after the Swedish astronomer Gunnar Malmquist (1893-1982); → bias.

A correction introduced into star counts distributed by apparent magnitude.

→ Malmquist bias; → correction.

The distribution law for kinetic energies (or, equivalently, speeds) of molecules of an ideal gas in equilibrium at a given temperature.

→ maxwell; → Boltzmann's constant; → distribution.

A plot representing the number of stars (or systems) per metallicity interval, usually expressed in [Fe/H] (abundance of → iron relative to → hydrogen).

→ metallicity; → distribution; → function.

The minimum distance between the paths of two orbiting objects around a → primary. Such distance between an object and Earth is called Earth MOID.

→ minimum; → orbit; → intersection; → distance.

A very thin fog consisting of an aggregate of microscopic water droplets or wet hygroscopic particles (of diameter not less than 0.5 mm), in which the visibility at the earth's surface is greater than 1 km.

O.E. mist "dimness, mist," from P.Gmc. *mikhstaz (cf. M.L.G. mist, Icelandic mistur), from PIE *migh-/*meigh-; cf. Pers. miq "fog, mist;" Gk. omikhle, O.C.S. migla, Skt. megha- "cloud, mist." → nebula.

Nezm "mist, fog," variants nezu, nezvâ "mist," nam "moisture, humidity;" Av. napta- "moist," nabās-câ- "cloud," nabah- "sky;" cf. Skt. nábhas- "moisture, cloud, mist;" Gk. nephos "cloud, mass of clouds," nephele "cloud;" L. nebula "mist," nimbus "rainstorm, rain cloud;" O.H.G. nebul; Ger. Nebel "fog;" O.E. nifol "dark;" from PIE *nebh- "cloud, vapor, fog, moist, sky."

1) An admirer of modern ideas, ways, etc.
2) Someone who practises or advocates → Modernism.

→ modern + → -ist.

A federal agency of the United States government founded in 1958 for civil aeronautical research and space exploration, superseding the National Advisory Committee for Aeronautics (NACA). Its goals include improving human understanding of the universe, the solar system, and Earth and establishing a permanent human presence in space. NASA is headquarted at Washington, D.C., and operates several research, development, and test facilities, as follows alphabetically: 1) Ames Research Center; 2) Dryden Flight Research Facility at Edwards, California, used for flight testing and as a landing site for the Space Shuttle; 3) Glenn Research Center at Cleveland, Ohio, concerned with aircraft and rocket propulsion; 4) Goddard Space Flight Center; 5) Jet Propulsion Laboratory; 6) Johnson Space center; 7) Kennedy Space Center; 8) Langley Research Center at Hampton, Virginia, which carries out research in aeronautics and space technology; 9) Marshall Space Flight Center; 10) the Space Telescope Science Institute; 11) Stennis Space Center, near Bay St Louis, Mississippi, for testing rocket engines; and 12) Wallops Flight Facility on Wallops Island, Virginia, which manages NASA's sounding rocket and scientific balloon programs.

→ national; → aeronautics; → space; administration, verbal noun of administer, from M.E. amynistre, from O.Fr. aministrer, from L. administrare "to serve, carry out, manage," from → ad- "to" + ministrare "to serve," from minister "servant, priest's assistant," from minus, minor "less," hence "subordinate," + comparative suffix *-teros.

Sâzmân, → organization; fazâyi pertaining to fazâ, → space; Âmrikâ "United State of America."

The → sciences, as → botany, → mineralogy, or → zoology, dealing with the study of all objects in → nature: used especially in reference to the beginnings of these sciences in former times (Dictionary.com).

→ natural; → history.

A specialized technician in an observatory who is in charge of functioning a telescope and helping visiting astronomers during their observation run.

From → night + assistant; M.E. assistent, from L. assistent-, stem of assistens, pr.p. of assistere "assist, stand by," from → ad- "to" + sistere "take a stand, cause to stand," cognate with Pers. istâdan "to stand," → histogram.

Dastyâr "assistant," from dast "hand" (Mid.Pers. dast; O.Pers. dasta-; Av. zasta-; cf. Skt. hásta-; Gk. kheir; L. praesto "at hand;" Arm. jern "hand;" Lith. pa-žastis "arm-pit;" PIE *ghes-to-) + yâr "helper; companion" (Mid.Pers. hayyâr "helper," hayyârêh "help, aid, assistance," Proto-Iranian *adyāva-bara-, cf. Av. aidū- "helpful, useful").

Not concerned with or based on the → theory of relativity. See also:
→ non-relativistic electron, → non-relativistic mechanics, → relativistic.

→ non-; → relativistic.

An electron that does not experience relativistic effects since its velocity is very small compared to that of light.

→ non-relativistic; → electron.

Mechanics in which the masses under consideration move at speeds much slower than the speed of light.

→ non-relativistic; → mechanics.