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

Device that produces an observable image that is brighter at output than the image at input.

→ image; → intensifier.

The action of making or becoming stronger or more extreme.

verbal noun of → intensify.

1) Something that intensifies.
2) Substance used to increase the density or contrast of an image on a photographic film or plate.

Agent noun of → intensify.

To make intense or more intense.
To increase the density and contrast of a photographic image by chemical treatment.

From → intense + -ify variant of -fy after a consonant, from O.Fr. fier, from L. -ficare "to do, make."

The spatial distribution of ionic species around an ionization source according to their → ionization potentials. The higher the ionization potential, the nearer to the source the corresponding ions will be.

→ ionization; → stratification.

A displacement in the spectral lines due to the different isotopes of an element.

→ isotope; → shift.

1) A reason, fact, circumstance, or explanation that justifies or defends. What is offered as grounds for believing an assertion.
2) An act of justifying.

Verbal noun of → justify.

Râstâvard, from râst "right, true; just, upright, straight" (Mid.Pers. râst "true, straight, direct;" O.Pers. rāsta- "straight, true," rās- "to be right, straight, true;" Av. rāz- "to direct, put in line, set," razan- "order;" cf. Skt. raj- "to direct, stretch," rjuyant- "walking straight;" Gk. orektos "stretched out;" L. regere "to lead straight, guide, rule," p.p. rectus "right, straight;" Ger. recht; E. right; PIE base *reg- "move in a straight line," hence, "to direct, rule") + âvard past stem of âvardan "to bring; to adduce, bring forward in argument or as evidence" (Mid.Pers. âwurtan, âvaritan; Av. ābar- "to bring; to possess," from prefix ā- + Av./O.Pers. bar- "to bear, carry," bareθre "to bear (infinitive)," bareθri "a female that bears (children), a mother;" Mod.Pers. bordan "to carry;" Skt. bharati "he carries;" Gk. pherein; L. fero "to carry").

1) To show (a claim, statement, act, etc.) to be right, reasonable, or proper.
2) To defend or uphold as warranted or well-grounded.
3) To adjust (a line of type) to fill a line of constant width.

Justify, from O.Fr. justifier "to show (something) to be just or right; to administer justice," from L. justificare "act justly toward, make just," from justificus "dealing justly, righteous," from justus "just, upright, equitable," from jus (gen. juris) "right," from O.Latin ious, from PIE base *yewes- (cf. Av. yaož-da- "to purify ritually, to revitalize;" Skt. yos- "(long) life" + root of facere "to do" (from PIE base *dhe- "to put, to do;" cf. Mod.Pers. dâdan "to give;" O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives; puts;" Skt. dadáti "puts, places;" Hitt. dai- "to place;" Gk. tithenai "to put, set, place;" Lith. deti "to put;" Czech diti, Pol. dziac', Rus. det' "to hide," delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do").

Râstâvard kardan, râstâvardan, infinitives of râstâvard, → justification.

1) An instrument for cutting, consisting essentially of a thin, sharp-edged, metal blade fitted with a handle.
2) Any blade for cutting, as in a tool or machine (Dictionary.com).

M.E. knif; O.E. cnif, probably from O.N. knifr; cf. M.L.G. knif, M.Du. cnijf, Ger. Kneif; of uncertain origin.

Kârd "knife," from Mid.Pers. kârt "knife;" Av. karət- "to cut;" cf. Skt. kart- "to cut," karəta- "knife;" Proto-Ir. *kart- "to cut."

The same as → Foucault knife-edge test.

→ knife; → edge; → test.

A tiny change in the → energy levels of the → hydrogen atom between the states 2S_1/2 and 2P_1/2, which creates a shift in the corresponding → spectral lines. The 2P_1/2 state is slightly lower than the 2S_1/2 state, contrarily to the Schrodinger's solution. The difference is explained by the interaction between → vacuum energy fluctuations and the hydrogen electron in different orbitals.

Named after Willis Eugene Lamb, Jr. (1913-2008), an American physicist who discovered this effect in 1951, and won the Nobel Prize in physics in 1955 "for his discoveries concerning the fine structure of the hydrogen spectrum;" → shift.

Same as → significance level.

→ level; → significance.

The condition that distinguishes living organisms from inorganic objects, i.e. non-life, and dead organisms. It is manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally.

O.E. life, from P.Gmc. *liba- (cf. O.N. lif "life, body," Du. lijf "body," O.H.G. lib "life," Ger. Leib "body"), properly "continuance, perseverance," from PIE *lip- "to remain, persevere, continue, live;" cf. Gk. liparein "to persist, persevere."

Zist "life, existence," from zistan "to live;" Mid.Pers. zivastan "to live," zivižn "life," zivik, zivandag "alive, living;" O.Pers./Av. gay- "to live," Av. gaya- "life," gaeθâ- "being, world, mankind," jivya-, jva- "aliving, alive;" cf. Skt. jiva- "alive, living;" Gk. bios "life;" L. vivus "living, alive," vita "life;" O.E. cwic "alive;" E. quick; Lith. gyvas "living, alive;" PIE base *gweie- "to live."

In fluid mechanics, the component of aerodynamical force which is perpendicular to the oncoming flow direction. In aeronautics, the perpendicular component of the force of the air against an airplane; the component that is effective in supporting the plane's weight. → drag; → thrust.

M.E. liften, from O.N. lypta "to raise;" cf. M.L.G. lüchten, Du. lichten, Ger. lüften "to lift;" O.E. lyft "heaven, air."

Bâlâbar "lift," from bâlâ "up, above, high, elevated, height" (variants boland "high," borz "height, magnitude" (it occurs also in the name of the mountain chain Alborz), Lori dialect berg "hill, mountain;" Mid.Pers. buland "high;" O.Pers. baršan- "height;" Av. barəz- "high, mount," barezan- "height;" cf. Skt. bhrant- "high;" L. fortis "strong" (Fr. & E. force); O.E. burg, burh "castle, fortified place," from P.Gmc. *burgs "fortress;" Ger. Burg "castle," Goth. baurgs "city," E. burg, borough, Fr. bourgeois, bourgeoisie, faubourg); PIE base *bhergh- "high") + bar present stem of bordan "to carry, transport" (Mid.Pers. burdan; O.Pers./Av. bar- "to bear, carry," barəθre "to bear (infinitive);" Skt. bharati "he carries;" Gk. pherein "to carry;" PIE base *bher- "to carry").

The process of recognizing the spectral lines in a spectrum.

→ line; → identification.

An equation in which the → dependent variable y and all its differential coefficients occur only in the first degree. A linear differential equation of → order  order n has the form:
f_n(x)y⁽ⁿ⁾ + f_n-1(x)y^(n-1) + ... + f₁(x)y^' + f₀(x)y = Q(x),
where f₀(x), f₁(x), ..., f_n(x) and Q(x) are each continuous functions of x defined on a common interval I and f_n(x)≠ 0 in I. A linear differential equation cannot have, for example, terms such as y² or (y^')^1/2. See also: → homogeneous linear differential equation; → nonhomogeneous linear differential equation.

→ linear; → differential; → equation.

A differential equation that has been derived from an original nonlinear equation.

Linearized, p.p. of → linearize; → differential; → equation.

A redshift characterizing a near-by receding object.

→ low; → redshift.

The process whereby the magnetic field tends to diffuse across the plasma and to smooth out any local inhomogeneities under the influence of a finite resistance in the plasma. For a stationary plasma the → induction equation becomes a pure → diffusion equation: ∂B/∂t = D_m∇²B, where D_m = (μ₀σ₀)^-1 is the → magnetic diffusivity.

→ magnetic; → diffusion.

The → diffusion coefficient for a magnetic field. It is expressed as: η = 1/(μ₀σ), where μ₀ is the → magnetic permeability and σ the → conductivity.

→ magnetic; → diffusivity.