An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



<< < arm lev war > >>

Number of Results: 43 Search : arm
lever arm
  بازوی ِ اهرم   
bâzu-ye ahrom (#)

Fr.: bras de levier   

The distance between the point of application of a → force and the → axis around which the object could → rotate.

lever; → arm.

Local Arm
  بازوی ِ محلی   
bâzu-ye mahali

Fr.: bras local   

One of the → spiral arms of the → Milky Way Galaxy which contains our → solar system. Same as → Orion Arm.

local; → arm.

velarm (#)

Fr.: tiède   

Moderately warm; tepid.

M.E. lukewarme "tepid," from luke "tepid," of unknown origin, + → warm.

Velarm "lukewarm, tepid," of unknown origin.

meteoroid swarm
  غنگ ِ شخانه‌وار   
qang-e šaxânevâr

Fr.: essaim de météoroïdes   

A relatively dense collection of meteoroids at certain spots along some → meteoroid streams.

meteoroid; → swarm.

Orion Arm
  بازویِ شکارگر، ~ ِ ا ُریون   
bâzu-ye Šekârgar, ~ Orion

Fr.: bras d'Orion   

A minor → spiral arm of the → Milky Way Galaxy close to which the → Sun is located. It is some 3,500 → light-years across and approximately 10,000 light-years in length. The solar system lies close to the inner rim of this spiral arm, about halfway along its length. Its name derives from the fact that the stars closest to the Sun which actually lie within the arm are in the constellation → Orion. Its other designations are → Local Arm, → Local Spur, → Orion Bridge, → Orion Spur, and → Orion-Cygnus Arm.

Orion; → arm.

Orion-Cygnus Arm
  بازوی ِ شکارگر-ماکیان   
bâzu-ye šekârgar-mâkiyân

Fr.: bras Orion-Cygne   

Same as → Orion Arm.

Orion; → Cygnus; → arm.

Perseus Arm
  بازوی ِ پرسءوس   
bâzu-ye Perseus

Fr.: Bras de Persée   

One of the spiral arms of the Galaxy. It is about 5000 light-years farther from the center than the local Orion Arm, in which the Sun lies.

Persus; → arm.

Sagittarius arm
  بازوی ِ نیم‌اسب   
bâzu-ye Nimasb

Fr.: bras du Sagittaire   

One of the → spiral arms of the Milky Way Galaxy. It lies between the Sun and the the → Scutum-Crux arm. Also known as the Sagittarius-Carina Arm.

Sagittarius; → arm.

Scutum-Crux Arm
  بازوی ِ سپر-چلیپا   
bâzu-ye Separ-Calipâ

Fr.: bras Écu-Croix   

A spiral arm of our Galaxy located between the Sagittarius Arm and the Norma Arm, though it is rather less prominent than either of these two better defined spiral arms. It originates relatively close to the Sun's present position in the Galaxy, and follows a sweeping arc of about 80,000 light years to the opposite side of the Galactic disk.

Scutum; → Crux; → arm.

simple harmonic motion
  جنبش ِ هماهنگ ِ ساده   
jonbeš-e hamâhang-e sâdé

Fr.: mouvement harmonique   

The motion of a body subjected to a restraining force which is directly proportional to the displacement from a fixed point in the line of motion. The equation of simple harmonic motion is given by x = A sin(ωt + θ0), where x is the body's displacement from equilibrium position, A is the → amplitude, or the magnitude of harmonic oscillations, ω is the → angular frequency, t is the time elapsed, and θ0 is the → initial phase angle.

simple; → harmonic; → motion.

simple harmonic oscillator
  نوشگر ِ هماهنگ ِ ساده   
navešgar-e hamâhang-e sâdé

Fr.: oscillateur harmonique simple   

An oscillator whose force is proportional to its extension, according to → Hooke's law. The way the oscillator moves is called → simple harmonic motion.

simple; → harmonic; → oscillator.

spherical harmonic
  هماهنگ ِ کره‌ای   
hamâhang-e kore-yi

Fr.: fonction harmonique sphérique   

A solution of some mathematical equations when → spherical polar coordinates are used in investigating physical problems in three dimensions. For example, solutions of → Laplace's equation treated in spherical polar coordinates. Spherical harmonics are ubiquitous in atomic and molecular physics and appear in quantum mechanics as → eigenfunctions of → orbital angular momentum. They are also important in the representation of the gravitational and magnetic fields of planetary bodies, the characterization of the → cosmic microwave background anisotropy, the description of electrical potentials due to charge distributions, and in certain types of fluid motion.

The term spherical harmonics was first used by William Thomson (Lord Kelvin) and Peter Guthrie Tait in their 1867 Treatise on Natural Philosophy; → spherical; → harmonic.

spiral arm
  بازوی ِ مارپیچ   
bâzu-ye mârpic

Fr.: bras spiral   

The region in a → spiral galaxy that contains concentrations of → gas, → dust, and → massive stars. Spiral arms are created by → density waves. See also → density wave theory.

spiral; → arm.

strong arm spiral galaxy
  کهکشان ِ مارپیچ با بازوی ِ سترگ   
kahkešân-e mârpic bâ bâzu-ye setorg

Fr.: galaxie spirale à forts bras   

A galaxy with prominent stellar → spiral arms and little star formation between stellar arms, such as M51.

strong; → arm; → spiral; → galaxy.


Fr.: essaim   

A great number of things especially in motion. → meteorite swarm.

ME; OE swearm; cf. O.S., M.L.G. swarm, Swed. svärm, M.Du. swerm, O.H.G. swarm, Ger. Schwarm "swarm;" O.N. svarmr "tumult."

Qang in Lârestâni "swarm of bees, flies, or the like," Lori qem (qem zaye) "swarm of bees, ants, and the like."

upper arm
bâzu (#)

Fr.: haut du bras   

The part of the → arm between the → shoulder and the → elbow.

upper; → arm.

Bâzu "arm," from Mid.Pers. bâzûk "arm;" Av. bāzu- "arm;" Mod.Pers. bâhu "stick, staff; arm;" cf. Skt. bāhu- "arm, forearm;" Gk. pechys "forearm, arm, ell;" O.H.G. buog "shoulder;" Ger. Bug "shoulder;" Du. boeg; O.E. bôg, bôh "shoulder, bough;" E. bough " a branch of a tree;" PIE *bhaghu- "arm").

garm (#)

Fr.: tiède   

Moderately hot.

M.E.; O.E. wearm (cf. O.S., O.Fris., M.Du., O.H.G., Ger. warm, O.N. varmr, Goth. warmjan "to warm"); cognate with Pers. garm, as below.

Garm "warm;" Mid.Pers. garm "warm;" O.Pers. garma-pada "name of the fourth month" (June-July); Av. garəma- "warm; heat;" cf. Skt. gharmá "heat;" Gk. therme, thermos; L. formus "warm;" E. warm, as above; PIE base *ghworm-/*ghwerm- "warm."

warm absorber
  درشمگر ِ گرم   
daršamgar-e garm

Fr.: absorbeur chaud   

A cloud of ionized gas within → active galactic nuclei (AGN) that causes absorption at → soft X-ray wavelengths. Warm absorbers were first suggested by Halpern (1984) to explain Einstein data of the quasar MR 2251-178. They are dubbed "warm" absorbers as they imply gas at temperatures of 104-105 K; the gas is → photoionized, not collisionally ionized. High resolution observations of warm absorbers have shown that they are outfowing. See also → cold absorber (Ceri Ellen Ashton, 2005, A Study of Warm Absorbers in Active Galactic Nuclei, Thesis, Mullard Space Science Laboratory Department of Space and Climate Physics University College London ).

warm; → absorber.

warm front
  پیشان ِ گرم   
pišân-e garm

Fr.: front chaud   

Meteo.: A leading edge that advances in a mass of air and replaces cooler air by warm air.

warm; → front.

warm intercloud medium
  مدیم ِ اندر-ابری ِ گرم   
madim-e andarabri-ye garm

Fr.: milieu internuage chaud   

A component of the → interstellar medium consisting of an extremely tenuous (density 0.1 to 10 cm-3) and relatively warm gas (temperature about 8,000 K) filling the space between denser neutral and ionized gas. Hydrogen is partly ionized, partly atomic and observed by the → 21-centimeter line in emission.

warm; → intercloud medium.

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