A unique feature of → Pluto's large satellite → Charon. It appears as a dark reddish area about 475 km in diameter in Charon's north polar region, as revealed in → New Horizons' approach images. It has been proposed that the feature is due to gas from Pluto. A part of Pluto's → atmosphere (→ methane molecules) is transiently cold-trapped and processed at Charon's winter pole (W. M. Grundy et al., 2016, Nature, 14 September).
Fr.: onde de Moreton
A large-scale → shock wave observed in Hα on the Sun's → chromosphere that is generated by the impact of a → solar flare. Moreton waves expand outward at about 1,000 km/s, and may travel for several hundred thousand kilometers. They are accompanied by meter-wave radio bursts.
Named after the American astronomer Gail E. Moreton (1960, A.J. 65, 494); → wave.
radebandi-ye Morgan-Keenan (#)
Fr.: classification de Morgan-Keenan
A system of → spectral classification introduced in 1943 by William W. Morgan (1906-1994), Philip C. Keenan (1908-2000), and Edith M. Kellman (1911-2007) at Yerkes Observatory. Also known as the MK (or MKK) classification or the → Yerkes system.
Named after the two main astronomers, as above; → classification.
The first part or period of the day, extending from dawn, or from midnight, to noon. Not a precise astronomical term.
From M.E. morn, morwen, from O.E. margen earlier morgen (cf. O.H.G. morgen, Goth. maurgins) + → -ing.
Bâmdâd, from Mid.Pers. bâmdâd"morning, dawn," from bâm "beam of light, splendor," bâmik "brilliant" (from Av. *bāma- "light," bāmya- "light, luminous, bright," vīspô.bāma- "all resplendent," from bā- "to shine;" cf. Skt. bhāti- "light, splendor") + dâd "given," from dâdan "to give" (O.Pers./Av. dā- "to give, grant, yield," dadāiti "he gives;" Skt. dadáti "he gives;" Gk. tithenai "to place, put, set," didomi "I give;" L. dare "to give, offer," facere "to do, to make;" Rus. delat' "to do;" O.H.G. tuon, Ger. tun, O.E. don "to do;" PIE base *dhe- "to put, to do").
rujâ (#), setâre-ye bâmdâd (#)
Fr.: étoile du matin
Not actually a star, but the planet Venus shining brightly in the east just before or at sunrise. Opposed to → evening star.
Rujâ "morning star" in Tabari, "star" in Gilaki. This word is a variant of official Pers. ruz "day," since in Tabari and Gilaki the phoneme z is sometimes changed into j, as in rujin = rowzan "window" and jir or jer = zir "under." Therefore it is related to rowšan "bright, clear," rowzan "window, aperture;" foruq "light," afruxtan "to light, kindle;" Mid.Pers. rôšn "light; bright, luminous," rôc "day;" O.Pers. raucah-rocânak "window;" O.Pers. raocah- "light, luminous; daylight;" Av. raocana- "bright, shining, radiant;" akin to Skt. rocaná- "bright, shining," roka- "brightness, light;" Gk. leukos "white, clear;" L. lumen (gen. luminis) "light," from lucere "to shine," related to lux "light," lucidus "clear," luna, "moon;" Fr. lumière "light;" O.E. leoht, leht, from W.Gmc. *leukhtam (cf. O.Fris. liacht, M.Du. lucht, Ger. Licht), from PIE *leuk- "light, brightness;" → morning; → star.
Of or relating to → morphology. Same as morphological
Of or relating to → morphology. Same as morphological
radebandi-ye rixtšenâxti (#)
Fr.: classification morphologique
A classification scheme of galaxies based on their apparent shape. → Hubble classification.
rixt, rixtšenâsi (#)
1) The study of the form or → structure of anything.
From Gk. morphe "form, shape, outward appearance" + → -logy.
Rixt "shape, the way something is cast, as in founding," past stem of rixtan "to cast; to pour; to flow" (Mid.Pers. rēxtan and rēcitan "to flow;" Av. raēk- "to leave, set free; to yield, transfer," infinitive *ricyā; Mod.Pers; rig in morderig "heritage" (literally, "left by the dead"); cf. Skt. rinakti "he leaves," riti- "stream; motion, course;" L. rivus "stream, brook;" Old Church Slavic rēka "river;" Rus. reka "river;" Goth. rinnan "run, flow," rinno "brook;" O.E. ridh "stream." šenâsi, → -logy.
Fr.: relation morphologie-densité
An observationally determined relationship between the → morphological classification of galaxies and the → environments in which they are located. Specifically, the morphology-density relation indicates that early-type galaxies (→ ETG) are preferentially located in high density environments, whereas late-type galaxies (→ LTG) are preferentially found in low density environments. Hence, spiral galaxies are rare in the high densities of clusters and are common in the lower density group environments. Early-type galaxies, on the other hand, are common in clusters and are rarely found in isolation.
A composite image built up from a number of image segments.
From O.Fr. mosaicq "mosaic work," from M.L. musaicum "mosaic work, work of the Muses," from musaicus "of the Muses," from L. Musa.
A female → parent.
M.E. mother, moder, O.E. modor; cf. O.S. modar, O.N. moðir, Da. moder, Du. moeder, O.H.G. muoter, Ger. Mutter; PIE *mater- "mother;" akin to Pers. mâdar, as below.
Mâdar, from Mid.Pers. mâd, mâdar; O.Pers./Av. mātar- "mother;" cf. Ossetic mad/madae "mother;" Khotanese mâta "mother;" Skt. mātár- "mother;" Gk. meter, mater; L. mater (Fr. mère, Sp. madre).
The action or process of moving or of changing place or position; movement.
Verbal noun of → move.
A device that imparts motion through reaction.
From L. motor "mover," from movere "to move."
Motor, loanword from Fr. moteur, as above.
A general term for a relatively bright or dark feature seen in monochromatic images taken in the red Hα → Balmer line of the solar → chromosphere. Mottles constitute the fine structure of the quiet solar chromosphere and are found near bright points at → supergranulation boundaries.
Probably back formation from motley, from M.E., O.E. mot "speck," of unknown origin; maybe related to Du. mot "sawdust, grit;" Norw. mutt "speck."
Capârak noun from capâr "spotted, speckled, mottled" + -ak diminutive/similarity suffix.
Mount Wilson Observatory
nepâhešgâh-e Mount Wilson
Fr.: Observatoire du Mont Wilson
An observatory situated on a mountain 1700 m above sea level near Pasadena, California. It was built in 1904 by American astronomer George Ellery Hale as a solar-observing station for the Yerkes Observatory, but it became an independent observatory funded by the Carnegie Institution of Washington. In 1908 a 60-inch (152-cm) reflector, then the largest in the world, was added for observations of stars and galaxies. Ten years later a 100-inch (254-cm) reflecting telescope was put into service. It was the most powerful telescope in the world until the construction of the Palomar 200-inch reflector in 1948. The 100-inch telescope's most important discovery was Edwin Hubble's determination of the distance to the Andromeda Nebula in 1924. He showed that the nebula lay beyond the bounds of the Milky Way Galaxy and hence was a galaxy in its own right. Then in 1929, following the work of Vesto Slipher, Hubble and his assistant Milton Humason demonstrated that galaxies were moving away from one another. This movement is the expansion of the Universe.
A natural elevation of the Earth's surface rising to a summit, and attaining an altitude greater than that of a hill.
From O.Fr. montaigne, from V.L. *montanea "mountain, mountain region," from L. montanus "mountainous," from mons (gen. montis) "mountain," minere "to project, jut, threaten," from PIE base *men- "to project;" cf. Av. matay-, mati- "protrusion of mountain range," framanyente "to be protruding, jutting;" from PIE base *men- "to stand out, to project;" (other related terms: mouth, prominent, amount, etc.).
Kuh "mountain," from Mid.Pers. kôf "mountain, hill; hump;" O.Pers. kaufa- "mountain;" Av. kaofa- "mountain."
âbohavâ-ye kuhestân (#)
Fr.: climat de montagne
Climate of relatively high elevations, specifically where optical observatories are situated.
The support structure for a telescope that bears the weight of the telescope and allows it to be pointed at a target.
From verb mount, from O.Fr. monter "to go up, climb, mount," from V.L. *montare, from L. mons (genitive montis) → mountain
Barnešând, noun of Barnešândan "to set, to fix, make sit," from bar- "on, upon, up" (Mid.Pers. abar; O.Pers. upariy "above; over, upon, according to;" Av. upairi "above, over," upairi.zəma- "located above the earth;" cf. Gk. hyper- "over, above;" L. super-; O.H.G. ubir "over;" PIE base *uper "over") + nešândan "to place one thing upon another, to fix, insert," from nešastan "to sit;" Mid.Pers. nišastan "to sit;" O.Pers. nišādayam [1 sg.impf.caus.act.] "to sit down, to establish," hadiš- "abode;" Av. nišasiiā [1 sg.subj.acr.] "I shall sit down," from nihad- "to sit down," from ni- "down, below, into," → ni-, + had- "to sit;" PIE base *sed- "to sit;" cf. Skt. sad- "to sit," sidati "sits;" Gk. hezomai "to sit," hedra "seat, chair;" L. sedere "to sit;" O.Ir. suide "seat, sitting;" Welsh sedd "seat;" Lith. sedmi "to sit;" Rus. sad "garden;" Goth. sitan, Ger. sitzen; E. sit.