An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 1015

Fr.: pseudo-bulbe   

A general designation for both → box-peanut and → disk-like bulges. Although both, as opposed to the → classical bulges, show important rotational support, they also have different properties.

pseudo-; → bulge.


Fr.: pseudo-disque   

A mass structure around a → protostar that resembles an → accretion disk, but is in fact a simple flattened envelope.

pseudo-; → disk.

pseudo-Euclidean space
  فضای ِ دروژ-اقلیدوسی   
fazâ-ye doruž-Oqlidosi

Fr.: espace pseudo-euclidien   

A real vector space of dimension n having a symmetric bilinear form (x, y) such that in some basis e1, ..., en, the quadratic form (x2) takes the form x12 + ... + xn - 12 - xn2. Such bases are called orthonormal.

pseudo-; → Euclidean; → space.


Fr.: pseudo-noyau   

Same → false nucleus.

pseudo-; → nucleus.

pseudo-Riemannian space
  فضای ِ دروژ-ریمانی   
fazâ-ye doruž-Riemanni

Fr.: espace pseudo-riemannien   

A space with an affine connection (without torsion), at each point of which the tangent space is a → pseudo-Euclidean space (Encyclopedia of Mathematics, Kluwer Academic Publications, Editor in chief I. M. Vinogradov, 1991).

pseudo-; → Riemannian; → space.


Fr.: pseudonyme   

A fictitious name used by an author to conceal his or her identity; pen name (

pseudo-; → name.


Fr.: pseudoscience   

Any set of ideas, methods, or assertions that claims to be objective and scientific but that in fact does not seriously value or attempt to apply objectivity and → scientific method to its endeavors. Pseudoscientific statements are usually not → falsifiable by means of → objective experimental or observational evidence, in contrast to scientific statements that can be refuted. Pseudoscience uses scientific-sounding terminology but totally lacks scientific support. Among pseudoscience examples are → astrology, scientology, clairvoyance, and parapsychology.

pseudo-; → science.

Ptolemaic astronomy
  اخترشناسی ِ بتلمیوس، ~ بطلمیوس   
axtaršenâsi-ye Batlamyus (#)

Fr.: astronomie ptoléméenne   

Ptolemaic system.

Ptolemaic system; → astronomy.

Ptolemaic system
  راژمان ِ بتلمیوس، ~ بطلمیوس   
râžmân-e Batlamyus

Fr.: système de Ptolémée   

An empirical model developed by Ptolemy about 150 A.D., in which a motionless Earth was the center of the Universe. The Sun, Moon, and planets revolved around the Earth in → eccentric circles and → epicycles. The fixed stars were attached to an outer sphere concentric with Earth. The Ptolemaic system gave the positions of the planets accurately enough for naked-eye observations, although it also had serious defects. As an extreme example, according to Ptolemy's model for the Moon, our satellite should appear to be almost twice as large when it is full than it is at quadrature, which is an absurdity since it is not seen as such.

Claudius Ptolemaeus was a mathematician, geographer, astronomer, and astrologer. The most influential of Greek astronomers, he lived in Roman Egypt, and was probably born there; he died in Alexandria in 165 A.D.; → system.

  ۱) همگان؛ ۲) همگانی   
1) hamegân (#); 2) hamegâni (#)

Fr.: 1) public; 2) publique   

1a) The community or people in general.
1b) A particular group of people with a common interest, aim, etc.
2a) Of, relating to, or concerning the people as a whole.
2b) Open or accessible to all.
Related concepts: → all, → general, → omni-, → total, → universal.

M.E., from L. publicus "of the people; of the state," also "common, general, public; ordinary," and as a noun, "a commonwealth; public property," from Old L. poplicus "pertaining to the people." from populus "people."

Hamegân, from hamé, → all, + -gân suffix forming plural entities, from Mid.Pers. -gânag, -gâna.

public opinion
  پژان ِ همگانی   
pažân-e hamegâni

Fr.: opinion publique   

The collective opinion of many people on some issue, problem, etc., especially as a guide to action, decision, or the like (

public; → opinion.


Fr.: publication   

1) The act of publishing a book, periodical, map, piece of music, engraving, or the like.
2) The act of bringing before the public; announcement.
3) The state or fact of being published (

Verbal noun of → publish.


Fr.: publicité   

1) Extensive mention in the news media or by word of mouth or other means of communication.
2) The state of being public, or open to general observation or knowledge (

public; → -ity.


Fr.: rendre public; farie de la publicité pour   

To give publicity to; bring to public notice, advertise.

public; → -ize.


Fr.: publier   

To issue (printed or otherwise reproduced textual or graphic material, computer software, etc.) for sale or distribution to the public (

M.E. publisshen, O.Fr. publier "make public, spread out, communicate," from L. publicare "make public," from publicus, → public.

Vâgândan "to diffuse, scatter, disperse," on the model of parâgandan, parâkandan "scatter, disperse," from vâ- "asunder, apart, off, away," → dis-, + gân variant of gan, kan (cf. Av. vikān- "to destroy," Kurd. nikândin "to bury"), from Proto-Ir. *kan- "to throw, place, put," → scatter.


Fr.: éditeur   

A person or company whose business is the publishing of books, periodicals, engravings, computer software, etc. (

Agent noun from → publish; → -er.

  پولسار، تپار   
pulsâr (#), tapâr (#)

Fr.: pulsar   

A rotating → neutron star that emits a radio → beam that is centered on the → magnetic axis of the neutron star. As the magnetic axis and hence the beam are inclined to the → rotation axis, a → pulse is seen every time the → rotation brings the → magnetic pole region of the neutron star into view. In this way the pulsar acts much as a light house does, sweeping a beam of radiation through space. The pulse or spin periods range from 1.4 milliseconds to 8.5 seconds. As neutron stars concentrate an average of 1.4 → solar masses on a diameter of only 20 km, pulsars are exceedingly → dense and → compact, representing the densest matter in the observable Universe. The pulsar radiation, chiefly emitted in → radio frequencies (0.1-1 GHz), is highly → polarized. The exact mechanism by which a pulsar radiates is still a matter of vigorous investigation. Simply put, an enormous electric field is induced by the rotation of a magnetized neutron star. The force of this field exceeds gravity by ten to twelve orders of magnitudes. Charged particles are whereby pulled out from the stellar surface resulting in a dense, magnetized plasma that surrounds the pulsar (→ magnetosphere). The charged particles flow out of the magnetic → polar caps of the neutron star, following the open magnetic field lines. The acceleration of the charged particles along the curved magnetic field lines will cause them to radiate (see, e.g., M. Kramer, 2010, astro-ph/1008.5032).
See also:
accreting neutron star, → anomalous X-ray pulsar, → binary pulsar, → black-widow pulsar, → Crab pulsar, → double pulsar, → Hulse-Taylor pulsar, → isolated neutron star (INS), → millisecond pulsar, → neutron star, → nulling fraction, → nulling pulsar, → optical pulsar, → pulsar glitch, → pulsar magnetosphere, → pulsar nulling, → pulsar planet, → pulsar wind nebula, → radio pulsar, → recycled pulsar, → rotation-powered pulsar (RPP), → Vela pulsar, → X-ray Dim Isolated Neutron Star (XDINS), → X-ray pulsar.

Pulsar, from puls(e) or puls(ing) + (st)ar.

Tapâr, from tap, → pulse, + (set)âr(é), from setâré, → star.

pulsar glitch
  گلس ِ پولسار، ~ تپار   
geles-e pulsâr, ~ tapâr


A sudden change in the pulsar period due to a sudden shift in the crust of the → neutron star (a → starquake).

pulsar; → glitch.

pulsar magnetosphere
  مغنات‌سپهر ِ پولسار   
meqnâtsepehr-e pulsâr

Fr.: magnétosphère de pulsar   

A dense zone of magnetized → plasma surrounding a → pulsar. The magnetosphere, lying between the surface of the → neutron star and the → light cylinder, corotates with the pulsar like a rigid body under the effect of strong magnetic field. The magnetosphere's thickness is determined by the constraint that the corotation velocity of its upper surface should not exceed the → speed of light.

pilsar; → magnetosphere.

pulsar nulling
  نولش ِ پولسار   
nuleš-e pulsâr

Fr.: phase d'arrêt de pulsar   

A phenomenon in which the → pulsar  → emission abruptly drops to zero or near zero for a certain number of → pulse  → periods, then suddenly returns to normal. Nulling is relatively common in pulsars. The → nulling fraction can be more than 80%. Investigating the emission behaviors of → nulling pulsars is important to understand the pulsar emission mechanism.

pulsar; → null; → -ing.

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