Fr.: grain interstellaire
porous dust grain
dâne-ye qobâr-e porlik
Fr.: grain de poussière poreux
A type of → interstellar dust grain made up of an aggregate of components with a hollow structure. Various processes operating in interstellar and → circumstellar media are believed to produce inhomogeneous and porous dust grains. Porous grains can produce more → extinction per unit mass than their combined individual dust components. They are generally cooler than compact grains (see, e.g., Iati et al. 2001, MNRAS 322, 749).
Fr.: grain pré-solaire
Fr.: arc-en-ciel primaire
The main rainbow that forms between about 40° and 42° from the
→ antisolar point
(or about 50° from the → antisolar point),
as viewed by the observer. The light path involves
→ refraction and a → single
→ reflection inside the water
→ droplet. If the drops are large, 1
millimeter or more in diameter, red, green, and violet are bright but
there is little blue.
Water that is condensed from the aqueous vapor in the atmosphere and falls to earth in drops greater than 0.5 mm in diameter.
M.E. rein; O.E. regn; cf. O.S. regan; O.N. regn; M.Du. reghen; Ger. Regen; maybe cognate with Pers. (Tabari) rag "thunder;" (Šahmirzâdi, Semnâni, Sorxe-yi) rak "thunder;" (Gilaki) râk "cloudburst;" L. rigare "to wet, moist;" PIE *reg- "rain, damp."
Bârân, from bâridan "to rain;" Mid.Pers. vârân "rain," vâritan "to rain;" Av. vār- "rain; to rain;" cf. Skt. vār- "rain, water; to rain;" L. urinari "to plunge under water, to dive;" Gk. ourein "to urinate;" PIE base *uer- "water, rain, river."
rain and snow mixed
Fr.: mélange de pluie et de neige
A precipitation consisting of rain and partially melted snow. It usually occurs when the temperature of the air layer near the ground is slightly above freezing. Called sleet in British English speaking countries, but not in the United States where the term has a different meaning in meteorology.
Šaliv, of dialectal origin, Kurd. šalêwa "rain and snow mixed," Aftari šelâp, Qasrâni šelâb with the same meaning, Tabari šalâb "strong cloudburst." The first element šal, šel, šor, šâr, âbšâr, šâridan "to flow." The second element iv, êw, âp, âb, → water.
Fr.: nuage de pluie
Any cloud from which rain falls.
Zafâk "rain cloud" (Dehxodâ); Mid.Pers. zafâ.
rangin kamân (#)
A color effect produced by the → refraction and → internal reflection of sunlight passing through a mist of tiny spherical water → droplets in the air. The effect is visible only when the observer has his back to the Sun. It appears as a colored band at about 138° from the Sun, hence 42° from the → antisolar pint. In other words, 42° is the angle between the direction of the → incident sunlight and the → line of sight. The → primary rainbow is caused from one reflection inside water droplets; the red color appears on the top and violet on the bottom. At solar elevations higher than 42° the bow is entirely below the → horizon and therefore invisible in the sky. A full rainbow is actually a complete circle, but from the ground we see only part of it. From an airplane, in the right conditions, one can see an entire circular rainbow. A → secondary rainbow appears if the sunlight is reflected twice inside the water droplets. Secondary rainbows are fainter, and the order of the color is reversed, with red on the bottom and violet on the top. See also: → Alexander's dark band, → supernumerary rainbow.
Fr.: angle d'arc-en-ciel
Fr.: rayon d'arc-en-ciel
The sunlight incident on a tiny spherical droplet of water.
The total liquid product of precipitation or condensation from the atmosphere, as received and measured in a rain gauge.
Bâreš verbal noun of bâridan "to rain," bâridan "to rain;" Mid.Pers. vârân "rain," vâritan "to rain;" Av. vār- "rain; to rain;" cf. Skt. vār- "rain, water; to rain;" L. urinari "to plunge under water, to dive;" Gk. ourein "to urinate;" PIE base *uer- "water, rain, river."
To hold back from action; keep in check; repress; to limit or hamper the activity, or effect of.
teleskop-e Schmidt-Cassegrain, durbin-e ~ (#)
Fr.: télescope Schmidt-Cassegrain
A mixture of the → Cassegrain telescope with a very short → focal length and of a Schmidt design (due to the presence of the → corrective plate), used mainly in → amateur astronomy. The main advantage of this telescope is its compact design. However, Schmidt-Cassegrain telescopes produce fainter images with less contrast than other telescope designs with similar → aperture sizes. This is due to the comparatively large → secondary mirror required to reflect the light back the → eyepiece.
Fr.: arc-en-ciel secondaire
A fainter rainbow appearing about 10° above the → primary rainbow, as viewed by the observer. The secondary rainbow is about twice as wide, and has its colors reversed.
Change of volume and/or shape of a body, or part of a body, due to an applied → stress. When a body is deformed by such a force, through compression or distension, the strain is the ratio of the dimensional change to the original or un-strained dimension. The strain may be a ratio of lengths, areas, or volumes. See also → shear.
M.E. streinen (v.), from O.Fr. estreindre "to bind tightly, clasp, squeeze," from L. stringere "to bind or draw tight," from PIE base *strenk- "tight, narrow; pull tight, twist;" cf. Gk. strangein "twist;" Lith. stregti "congeal;" O.H.G. strician "mends nets;" Ger. stramm, Du. stram "stiff."
Šepil "squeeze; fondness" (Dehxodâ) of unknown origin.
Fr.: arc-en-ciel surnuméraire
qatâr (#), teran (#)
1) A series or sequence of objects or events.
M.E., from O.Fr. train "tracks, path, trail; act of dragging," from trainer "to pull, drag, draw," from V.L. *traginare, from *tragere "to pull," back-formation from tractus, p.p. of L. trahere "to pull, draw."
Qatâr "a row of camels," loan from Ar.; teran, loan from Fr., as above.
very small grain (VSG)
dâne-ye besyâr kucak
Fr.: très petit grain
A special type of carbonaceous → interstellar dust grains with a size ranging from 10 to 150 Å and consisting of tens to hundreds of atoms. In contrast to → big grains, VSGs are not in → thermal equilibrium. They can be heated to very high temperatures (~ 1000 K) by the absorption of a single photon. It is thought that VSGs are clusters of → PAH.
qatâr-e mowj (#), mowj-teran
Fr.: train d'onde
A series of successive waves spaced at regular intervals.