An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1002
pencil beam
  تابه‌ی ِ باریک   
tâbe-ye bârik

Fr.: faisceau étroit   

A beam of radiant energy in the form of a narrow cone or cylinder.

pencil; → beam.

Pencil Nebula (NGC 2736)
  میغ ِ کلک   
miq-e kelk

Fr.: Nébuleuse du Crayon   

A small part of the → Vela supernova remnant with a narrow appearance. The Pencil Nebula measures about 0.75 → light-years across, is about 5 light-years long, and lies about 800 light-years from Earth. It is moving through the → interstellar medium at about 650 000 kilometres per hour.

pencil; → nebula.

pencil of light
  باریکه‌ی ِ نور   
bârike-ye nur (#)

Fr.: pinceau lumineux   

A small bundle of → rays of light. See also → beam of light.

M.E. pencel, from M.Fr. pincel, from L. penicillus "painter's brush or pencil," diminutive of peniculus "little tail," diminutive of penis "tail;" → light.

Bâriké, from bârik, → narrow, + nuance suffix ; nur, → light.

âvang (#)

Fr.: pendule   

In its simple form, a device consisting of a body suspended from a fixed point on the end of a string to move to and fro by the action of gravity and acquired momentum. The period of oscillation for small amplitudes of swing is determined by the formula T = 2π √(l/g).

From Mod.L. pendulum, noun use of neuter of L. pendulus "hanging down," from pendere "to hang."

&ACIRC;vang, related to âvixtan, âviz- "to hang" (akin to bixtan, biz- "to shake, to sort out, to sift"); Mid.Pers. âwixtan "to hang" (Sogdian wyc "to move, shake;" Chorasmian wc- "to tremble, shake;" Ossetic wigyn "to shake," awynzyn "to hang"), from prefixed (â-) Proto-Iranian base *uij-, *uic- "to shake, swing;" cf. Av. vij- "to shake, swing," vaējant- "swinging;" cf. Skt. vej- "to tremble, wince."

pendulum day
  روز ِ آونگی   
ruz-e âvangi

Fr.: jour pendulaire   

The time required for the plane of a freely suspended → Foucault pendulum to complete an apparent rotation about the local vertical. It is given by T = 23.9344 / sin φ in hours, where φ represents the latitude of the place. For Paris it is 31h 47m 38s; for the poles it 23.9344 h and for the equator it is ∞ since the plane of pendulum does not turn.

pendulum; → day.

Penrose process
  فراروند ِ پنروز   
farâravand-e Penrose

Fr.: processus de Penrose   

A hypothetical means of extracting energy from a rotating black hole. If a particle spirals into the ergosphere of a black hole in a direction counter to the rotation of the black hole, and if the particle then breaks up into two fragments inside the ergosphere, one of the fragments can escape with energy greater than the energy of the original particle.

Named after Roger Penrose, English physicist (1931-), who devised the process; → process.

Penrose theorem
  فربین ِ پنروز   
farbin-e Penrose

Fr.: théorème de Penrose   

A collapsing object whose radius is less than its Schwarzschild radius must collapse into a singularity.

Penrose process; → theorem.

Penrose-Carter diagram
  نمودار ِ پنروز-کارتر   
nemudâr-e Penrose-Carter (#)

Fr.: diagramme de Penrose-Carter   

A diagram involving → formal compactification of → space-time used in → general relativity to describe the causal properties of the space-time. Only two of the space dimensions are shown and horizontal lines represent space, while vertical lines belong to time. The → null geodesicss are at 45°, which facilitates the visualization of → light cones. The major feature of Penrose-Carter diagram is representing the whole space-time on a finite surface, while putting → spacelike and → timelike infinities at finite distance.

Named for Roger Penrose (1931-) and Brandon Carter (1942-) who introduced it independently; → diagram.

panj- (#)

Fr.: penta-   

Prefix denoting five, fivefold (e.g. pentacyclic, pentahedron, pentahydrate).

From Gk. pent-, penta-, combining forms from pente "five;" cognate with Pers. panj, E. five, as below.

Panj, from Mid.Pers. panj, Av. panca; cf. Skt. pánca; Gk. pente; L. quinque; O.E. fif, from P.Gmc. *fimfe (O.S. fif, O.H.G. funf); from PIE base *penkwe "five."

nimsâyé (#)

Fr.: pénombre   

1) The portion of a shadow in which light from an extended source is partially but not completely cut off by an intervening body; the area of partial shadow surrounding the umbra.
2) The lighter part of a shadow during an eclipse. An observer standing in the penumbra of a Solar eclipse will see a partial eclipse.
3) The lighter zone surrounding the dark area (→ umbra) of a → sunspot. It consists of fine, light filaments which are approximately radial for sunspots with circular outline, but irregular for complex spots.

N.L., from L. pæne "almost" + → umbra "shadow."

Nimsâyé, from nim "mid-, half" (Mid.Pers. nêm, nêmag "half;" Av. naēma- "half;" cf. Skt. néma- "half") + sâyé, → shadow; →umbra.

nimsâye-yi (#)

Fr.: pénombral   

Of or relating to a → penumbra.

penumbra; → -al.

penumbral lunar eclipse
  ماه‌گرفت ِ نیمسایه‌ای   
mâhgereft-e nimsâye-yi

Fr.: éclipse de lune pénombrale   

A lunar eclipse that occurs when the Moon passes through the Earth's → penumbra, but misses the darker umbral shadow. Because the Moon is only partially dimmed, a penumbral eclipse is not impressive. Total penumbral eclipses are rare, and when these occur, that portion of the Moon which is closest to the umbra can appear somewhat darker than the rest of the Moon.

penumbral; → eclipse.


Fr.: pivoine   

Any plant of the genus Paeonia, having showy, pink, red, or white, globular flowers. Originally cultivated in the temperate regions of Asia, China, Europe, and the northwest parts of North America.

M.E., from M. Fr. peonie, pioiné, from L.L. peonia, from L. pæonia, from Gk. paionia, perhaps from Paion, physician of the gods. The plant was recognized to possess many remedial properties, and was thus given an association with the gods.

Payoniyâ, loan from Gk, as above.

Peony star
  ستاره‌ی ِ پیونیا   
Setâre-ye Payoniyâ

Fr.: Etiole Pivoine   

A peony-shaped nebula around the → Wolf-Rayet star WR 102ka as shown by the → Spitzer Space Telescope image at 24 μm. The formation of this infrared bright nebula is attributed to the recent evolutionary history of WR 102ka during → LBV-type eruptions and/or its strong → stellar wind (see, e.g., A. Barniske et al. 2008, A&A 486, 971).

peony; → star.

mardom (#)

Fr.: gens, personnes, peuple, public   

1) Persons indefinitely or collectively; persons in general.
2) Human beings, as distinguished from animals or other beings (

M.E. peple, from O.Fr. peupel "people, population, crowd; mankind," from L. populus "a people, nation; a multitude, crowd," of unknown origin.

Mardom "man, human being, mankind, people;" from Mid.Pers. mardôm "human being, man, mankind, people" (from *mard-tohm "seed of man"), from mard "man, humanity" (cognate with mordan "to die"); O.Pers. martiya-; Av. marəta- "mortal, man," maša- "mortal;" cf. Skt. márta- "mortal, man;" Gk. emorten "died;" L. mortalis "subject to death."

1) par-; 2) per-

Fr.: per-   

1) A prefix meaning "through, thoroughly, utterly, very."
2) Chemistry: A prefix used in the names of inorganic chemical compounds containing an element in its highest oxidation state or containing a large or the largest possible proportion of an element.

From L. per "through, during, by means of, on account of," cognate with Pers. par-, pirâ-, as below; cf. Gk. → peri- "around, about, beyond;" O.C.S. pre-; Russ. pere- "through;" Lith. per "through;" Goth. fair-; Ger. ver-; O.E. fer-.

Par-, per-, variants of pirâ- "around, about," from Mid.Pers. pêrâ; O.Pers. pariy "around, about;" Av. pairi "around, over," per- "to pass over, beyond;" cf. Skt. pari; Indo-Iranian *pari- "around;" cf. Gk. peri "around, about, beyond;" L. per "through," as above; PIE base *per- "through, across, beyond."


Fr.: concevoir   

1) To become aware of, know, or identify by means of the senses.
2) To recognize, discern, envision, or understand (

M.E. perceiven, from Anglo-Fr. *perceivre, from O.Fr. percoivre "perceive, notice, see; understand," from L. percipere "obtain, seize entirely, take possession of," from L. → per- "thoroughly" + capere "to take," → concept.

&ACIRC;gertidan, from â- intensive prefix + gertidan "to take, seize," → concept.



The mental product of the act of perceiving, as distinguished from the thing perceived.



Fr.: perception   

The process of recognizing or identifying something. Usually employed of sense perception, when the thing which we recognize or identify is the object affecting a sense organ.

Verbal noun of → perceive.

perklorât (#)

Fr.: perchlorate   

Any salt of perchloric acid.

per-; → chlorate.

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