An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1330
Copernican model
  مدل ِ کوپرنیک   
model-e Kopernik

Fr.: modèle copernicien, ~ de Copernic   

A model of the Solar System proposed by Copernicus in which the Sun lies at the center with the planets orbiting around it. In this model, the Earth is a planet, and the Moon is in orbit around the Earth, not the Sun. The stars are distant objects that do not revolve around the Sun. Instead, the Earth is assumed to rotate once in 24 hours, causing the stars to appear to revolve around the Earth in the opposite direction. This model readily explained both the varying brightness of the planets and the → retrograde motion. In the Copernican model the planets executed uniform circular motion about the Sun. As a consequence, the model could not explain all the details of planetary motions on the celestial sphere without → epicycles of the → Ptolemaic system. However, the Copernican system required many fewer epicycles than its predecessor because it moved the Sun to the center. Hence, Copernicus borrowed elements from variants of the Ptolemaic system developed by Middle Eastern astronomers, mainly the Iranian Nasireddin Tusi (1201-1274) and the Damascene Ibn al-Shatir (1304-1375), which Copernicus apparently knew about.

Nicolaus Copernicus (1473-1543), the L. rendition of the Polish original name Mikołaj Kopernik, author of the epoch making work De revolutionibus orbium coelestium (On the Revolutions of the Celestial Spheres), published in 1543, in which he exposed his heliocentric system; → model.

Copernican principle
  پروز ِ کوپرنیکی   
parvaz-e Koperniki

Fr.: principe copernicien   

1) Physics: A basic statement that there should be no "special" observers to explain the phenomena. The principle is based on the discovery by Copernicus that the motion of the heavens can be explained without the Earth being in the geometric center of the system, so the Aristotelian/Ptolemaic assumption that we are observing from a special position can be given up.
2) Exobiology: By extension, human beings and the Earth are not at the centre of the → Universe and therefore are not "special". Life would therefore be commonplace. Compare → anthropic principle.

Copernican model; → principle.

coplanar forces
  نیروهای ِ هم-هامن   
niruhâ-ye ham-hâmon

Fr.: forces coplanaires   

A system of forces acting on a body that all are in the same plane.

com- + planar adj. from → plane.

mes (#)

Fr.: cuivre   

A malleable, ductile, reddish metal with a bright luster that is known from antiquity, and has been mined for some 5000 years; symbol Cu. → Atomic number 29; → atomic weight 63.546; → melting point 1,083.4°C; → boiling point 2,567°C; → specific gravity 8.96 at 20°C. Copper is an excellent conductor of heat and electricity and is widely used for various purposes, either pure or in numerous alloys such as bronze and brass in combination with → tin and → zinc. Its → radioactive isotopes have half-lives from 5.10 min (66Cu) to 61.0 hr (67Cu). Copper is mostly created inside → massive stars, via the → s-process, after they leave the → main sequence.

M.E. coper; O.E. coper, copor; cf. O.N. koparr, Ger. Kupfer, the original Germaic word from L.L. cuprum, contraction of L. Cyprium (æs) "Cyprian (metal)," referriing to the island which was the primary source of copper for the Romans, after Gk. Kyprios "Cypress," literally "land of cypress trees."

Mes "copper," of unknown origin; maybe related to Skt. māsaka- "a weight of gold;" Pali māsa- "a small coin, of copper, of very low value;" Prakrit māsa-.

pacen (#)

Fr.: copie   

A reproduction, imitation; a thing made to be like another.

M.E. copie, from O.Fr. copie, from M.L. copia "reproduction, transcript," from L. copia "plenty," from → com- "with" + ops "power, wealth."

Pacen, from Mid.Pers. pacên "copy," ultimately from Proto-Ir. *pati-cak- "strike against, beat through," i.e. "stamp;" from *pati- + *cak- "to strike;" compare with Ger. Durchschlag "copy" literally "striking through;" related to câk "fissure."

  پچن-راشن، داتار-راشن، راشن ِ داتار   
pacen-râšan, dâtâr-râšan, râšan-e dâtâr

Fr.: droit d'auteur   

The legal right of the owner of intellectual property (such as a book, play, film, photograph, or piece of music). Simply put, copyright is the right to copy.

copy; → right; → author.

  تار، ریسمان   
târ (#), rismân (#)

Fr.: corde   

1) A string or thin rope made of several strands braided, twisted, or woven together.
2) A cordlike structure (

M.E., from O.Fr. corde "rope, string, cord," from L. chorda "string of a musical instrument, cat-gut," from Gk. khorde "string, catgut, chord, cord," from PIE root *ghere- "intestine" (



Fr.: Cordelia   

The innermost of → Uranus' known satellites. Cordelia has a diameter of 26 km and orbits Uranus at a mean distance of 49,752 km. It was discovered from the images taken by Voyager 2 in 1986. Cordelia is the inner → shepherd moon for Uranus's Epsilon ring. → Ophelia.

Named after the daughter of Lear in Shakespeare's play King Lear.


Fr.: cœur, noyau   

1) The central region of a star in which energy is generated by → thermonuclear reactions.
2) The central region of a planet or satellite which has a → differentiated interior.
3) The innermost and densest layer of the Earth, lying from 2890 km to 6360 km beneath the surface. It consists primarily of the metals iron and nickel, and is divided into the → outer core, which is believed to be liquid, and the → inner core, which is believed to be solid.
4) The central region of a → star cluster.
5) A flat → density profile representing the distribution of stars in the central region of a galaxy. Cores are found in high mass galaxies. They are believed to result from the interaction of a central → supermassive black hole with another merging black hole.
6) A progenitor of → protostars. → dense core.
7) → reactor core.

Probably from O.Fr. cœur "core of fruit," literally "heart," from L. cor "heart," cf. Gk. kardia: P.Gmc. *khertan- (O.E. heorte, E. heart, Ger. Herz, Bret. kreiz "middle"), Skt. hrd-; Av. zərəd-; Mid.Pers. dil; Mod.Pers. del; Baluci zird; Arm. sirt; PIE base *kerd- "heart".

Maqzé, from maqz "kernel; brain; marrow" + nuance suffix . Mod.Pers. maqz from Mid.Pers. mazg "brain; marrow," Av. mazga- "marrow; brain" cf. Skt. majján- "marrow," P.Gmc. *mazga-, O.E. mearg "marrow," Lith. smagenes "brain," O.H.G. mark "marrow," PIE base *mozgho- "marrow, brain".

core collapse
  رمبش ِ مغزه   
rombeš-e maqzé

Fr.: effondrement de cœur   

The collapse of a → massive star's core at the → final → stages of its → evolution when the core consists entirely of → iron (→ iron core). Since iron cannot burn in → nuclear reaction, no energy is generated to support the → gravitational collapse. The result will be a → supernova explosion of → Type Ib, → Type Ic, or → Type II. See also → core-collapse supernova.

core; → collapse.

core elliptical galaxy
  کهکشان ِ بیضی‌گون ِ مغزه‌دار   
kahkešân-e beyzigun-e maqzedâr

Fr.: galaxie elliptique à coeur   

An → elliptical galaxy that displays a → surface brightness profile with a distinct break from a steep outer slope to a shallower inner → cusp. Core profiles mainly occur in very luminous elliptical galaxies and are considered the result of dissipation-less → mergers of two galaxies that have central → supermassive black holes (S. P. Rusli et al., 2013, AJ 146, 160).

core; → elliptical; → galaxy.

core mass function (CMF)
  کریای ِ جرم ِ مغزه   
karyâ-ye jerm-e maqzé

Fr.: fonction de masse des cœurs   

The mass distribution of → pre-stellar cores in → star-forming regions. The CMF is usually represented by dN/dM = Mα, where dM is the mass interval, dN the number of cores in that interval, and α takes different values in different mass ranges. In the case of → low-mass stars, it is found that the CMF resembles the → Salpeter function, although deriving the masses and radii of pre-stellar cores is not straightforward. The observational similarity between the CMF and the → initial mass function (IMF) was first put forth by Motte et al. (1988, A&A, 336, 150), and since then many other samples of dense cores have been presented in this context. For example, Nutter & Ward-Thompson (2007, MNRAS 374, 1413), using SCUBA archive data of the Orion star-forming regions, showed that the CMF can be fitted to a three-part → power law consistent with the form of the stellar IMF. Recent results, obtained using observations by the → Herschel Satellite, confirm the similarity between the CMF and IMF with better statistics (Könyves et al. 2010, A&A, 518, L106; André et al. 2010, A&A, 518, L102). Moreover, these works show that the CMF has a → lognormal distribution (i.e. dN/dlog M follows a → Gaussian form against log M), as is the case for the IMF at low masses (below about 1 solar mass).

core; → mass; → function.

core overshooting
  فرازد ِ مغزه   
farâzad-e maqzé

Fr.: dépassement du cœur   

convective overshooting.

core; → overshooting.

core profile
  فراپال ِ مغزه   
farâpâl-e maqzé

Fr.: profil de cœur   

A → profile representing the number density of stars in the → core of a galaxy.

core; → profile.

core-collapse supernova
  اَبَر-نو‌اختر ِ رمبش ِ مغزه   
abar-now-axtar-e rombeš-e maqzé

Fr.: supernova à effondrement de coeur   

A supernova arising from the → core collapse of a → massive star. Same as → Type Ib, → Type Ic, or → Type II supernova.

core; → collapse; → supernova.

core-dominated quasar
  کو‌آسار ِ مغزه چیره   
kuâsâr-e maqzé ciré

Fr.: quasar dont l'émission de cœur domine   

A → radio-loud quasar in which the central source is enhanced by → relativistic beaming and characterized by a → flat  → spectrum. It has been conjectured that this phenomenon is an → orientation effect. If a radio-loud quasar is seen along its → jet, it will appear as a core-dominated source. See also → lobe-dominated quasar.

core; → dominate; → quasar.

core-halo galaxy
  کهکشان ِ مغزه-هاله   
kahkešân-e maqzé-hâlé

Fr.: galaxie cœur-halo   

A radio galaxy characterized by an emission "halo" surrounding a more intense "core". About 20% of the known extended radio sources are of the core-halo type.

core; → halo; → galaxy.


Fr.: éclat de cœur   

The → mid-infrared radiation which is scattered by unusually large → dust grains in the denser core regions of → molecular clouds. It occurs between 3 and 5 μm, when the light from nearby stars undergoes → scattering by the grains provided that they are about 1 μm in size, instead of 0.1 μm, as previously thought. Coreshine, which was detected in Spitzer IRAC data, is a widespread astronomical phenomenon. It is found across dozens of → dark clouds in the Galaxy and during all the phases of the → low-mass star formation (Pagani et al. 2010, Science, 329, 1622). See also → cloudshine.

core; → shine.

Coriolis acceleration
  شتاب ِ کوریولیس   
šetâb-e Coriolis (#)

Fr.: accélération de Coriolis   

The apparent acceleration corresponding to the → Coriolis force. It is the acceleration which, when added to the acceleration of an object relative to a rotating → reference frame and to its → centrifugal acceleration, gives the acceleration of the object relative to a fixed reference frame. Coriolis acceleration equals 2ω x v, where ω is the → angular velocity of the rotating reference frame and v is the radial velocity of a particle relative to the center of the rotating reference frame.

Coriolis effect; → force.

Coriolis effect
  اسکر ِ کوریولیس   
oskar-e Koriolis

Fr.: effet Coriolis   

The apparent → deflection of a body in motion with respect to the Earth, as seen by an → observer on the Earth, caused by the → Earth's rotation. Thus, a projectile fired due north from any point on the northern hemisphere will land slightly east of its target (deflection to the right). This involves two factors: 1) the eastward velocity of Earth's surface decreases from the → equator to the → poles, and 2) when an object starts to move north or south without being firmly connected to the ground it maintains its initial eastward speed (conservation of → angular momentum). Hence, an object travelling away from the equator will be heading east faster than the ground and will seem to be forced east. On the other hand, a ball fired in the northern hemisphere toward the equator deflects to the west. As for the southern hemisphere, a ball fired southward will deflect East. The projectile is not subject to this effect only on the equator, when it is thrown in an east-west direction. The Coriolis effect is therefore greater at higher → latitudes and smaller near the equator. This effect is of paramount importance to the large-scale → atmospheric circulation, the development of storms, and the sea-breeze circulation. In low pressure systems, i.e. zones where air ascends, the air is less dense than its surroundings and this creates a center of low atmospheric pressure. Winds blow from areas of high pressure to areas of low pressure, and so the surface winds would tend to blow toward a low pressure center. But, because of the Coriolis effect, they are deflected. In the northern hemisphere they are deflected toward the right, and fail to arrive at the low pressure center, but instead circulate around it → counterclockwise. In the southern hemisphere the circulation around a low pressure center would be → clockwise. Regarding high pressure systems in the northern hemisphere, a general clockwise rotation is created around the center. Same as the → Coriolis force. See also → geostrophic wind, → geostrophic flow.

Named after Gaspard Gustave Coriolis (1792-1843), French engineer and mathematician who first described this effect; → effect.

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