An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 177 Search : log
Bianchi cosmological model
  مدل ِ کیهانشناختی ِ بیانکی   
model-e keyhânšenâxti-ye Bianchi

Fr.: modèle cosmologique de Bianchi   

A cosmological model based on the theory of → general relativity, which is homogeneous but → anisotropic. There are actually ten dinstinct Bianchi types, classified according to the particular kinds of symmetry they posses.

Luigi Bianchi (1856-1928), Italian mathematician; → cosmological; → model.

biologist
  زیست‌شناس   
zistšenâs (#)

Fr.: biologiste   

An expert or specialist in biology.

Biologist, from → biology + → -ist.

biology
  زیست‌شناسی   
zistženâsi (#)

Fr.: biologie   

The study of living organisms and their interactions with the non living world.

Biology, from → bio- + → -logy.

bivalent logic
  گوییک ِ دو-ارز   
guyik-e do-arz

Fr.: logique bivalente   

A logical system, such as → classical logic, in which every declarative sentence expressing a → proposition has exactly one → truth value, either → true or → false. Bivalent logic is just a sub-set of a more powerful type of logic known as → fuzzy logic. See also → polyvalent logic.

bivalent; → logic.

Caldwell Catalog
  کاتالوگ ِ کالدول   
kâtâlog-e Caldwell

Fr.: catalogue de Caldwell   

A collection of 109 impressive celestial objects compiled for amateur astronomers. These objects (→ star clusters, → nebulae, → supernova remnants, and → galaxies), selected from the → New General Catalog and the → Index Catalog, are not present in the → Messier catalog.

Named after Patrick Caldwell Moore (1923-2012), English amateur astronomer, who compiled the catalog in 1995; → catalog.

catalog
  کاتالوگ   
kâtâlog (#)

Fr.: catalogue   

A list or record of items systematically arranged with descriptive details. → Index Catalogue; → Messier catalog; → New General Catalogue.

M.E. cathaloge, cateloge, from M.Fr. catalogue, from L.L. catalogus, from Gk. katalogos "a list, register," from kata "down, completely" + legein "to say, count," → -logy.

Kâtâlog, loan from Fr., as above.

catalog place
  جای ِ کاتالوگی   
jâ-ye kâtâlogi

Fr.: position catalogue   

Same as catalog position and → mean catalog place.

catalog; → place.

catalog position
  نهش ِ کاتالوگی   
neheš-e kâtâlogi

Fr.: position catalogue   

Same as catalog place and → mean catalog place.

catalog; → position.

categorical syllogism
  باهمشماری ِ کتاگریک   
bâhamšomâri-ye katâgorik

Fr.: syllogisme catégirique   

A standard → syllogism that consists of three → categorical propositions in which there are three terms, and each term appears exactly twice. The three terms in a standard categorical syllogism are the → major term, → mino term, and → middle term.

categorical; → syllogism.

chronology
  گاه‌شناسی، گاه‌راییک   
gâhšenâsi, gâhrâyik

Fr.: chronologie   

The science of dating, of ordering time, of arranging in periods, and of determining temporal distances between past events.

Chronology, from Gk. khronos "time" + → -logy.

Gâhšenâsi, from gâh "time" + -šenâsi, → -logy. Gâhrâik, from gâh + rây, ârâ "order, arrangement" stem of ârâstan "to arrange, to set in order, adorn" (Mid.Pers. ârây-, ârâstan "to arrange, adorn," O.Pers. râs- "to be right, straight, true," râsta- "straight, true" (Mod.Pers. râst "straight, true"), râd- "to prepare," Av. râz- "to direct, put in line, set," Av. razan- "order," Gk. oregein "to stretch out," L. regere "to lead straight, guide, rule," p.p. rectus "right, straight," Skt. rji- "to make straight or right, arrange, decorate," PIE base *reg- "move in a straight line") + -ik, → -ics.

classical logic
  گوییک ِ کلاسیک   
guyik-e kelâsik

Fr.: logique classique   

The traditional logic in which → sets are sharply defined (→ crisp set) for example, the number of students registered for a course, or the names beginning with P in a given telephone directory. Classical logic also defines relations between sets of → propositions. Consider for example two sets: elephants and mammals, a simple proposition would be the assertion that all elephants are mammals, that is E ⊂ M, where E is the elephant set and M is the mammal set. The classical logic proposition is either true or false. Compare with → fuzzy logic.

classical; → logic.

climatology
  کلیماشناسی   
kelimâšenâsi

Fr.: climatologie   

The scientific study of climates. More specifically, the analysis of weather condition trends over a relatively long period of time (past, present or future). Climatology is distinct from meteorology, which is associated with short-term weather system studies.

climate; → -logy.

clog
  کتله   
katelé

Fr.: sabot   

A shoe made of wood.

M.E., of unknown origin.

Katelé, from (Tabari, Gilaki) katelé "wooden shoe," from katel "tree log, tree stump."

Collinder catalog
  کاتالوگ ِ کولیندر   
kâtâlog-e Collinder

Fr.: catalogue de Collinder   

A catalog of → open clusters published in 1931.

Named after Per Collinder (1890-1975) the Swedish astronomer who created the catalog; → catalog.

common logarithm
  لگاریتم ِ دهدهی   
logâritm-e dahdahi

Fr.: logarithme décimal   

The logarithm with → base 10. It is known also as the → decimal logarithm, decadic logarithm, or Briggsian logarithm, after Henry Briggs, an English mathematician who pioneered its use.

common; → logarithm; → decimal.

conformal cyclic cosmology (CCC)
  کیهانشناسی ِ چرخه‌ای ِ همدیس   
keyhânšenâsi-ye carxe-yi-ye hamdis

Fr.: cosmologie cyclique conforme   

A cosmological model developped by Roger Penrose and colleagues according which the Universe undergoes repeated cycles of expansion. Each cycle, referred to an aeon, starts from its own "→ big bang" and finally comes to a stage of accelerated expansion which continues indefinitely. There is no stage of contraction (to a "→ big crunch") in this model. Instead, each aeon of the universe, in a sense "forgets" how big it is, both at its big bang and in its very remote future where it becomes physically identical with the big bang of the next aeon, despite there being an infinite scale change involved, on passing from one aeon to the next. This model considers a conformal structure rather than a metric structure. Conformal structure may be viewed as family of metrics that are equivalent to one another via a scale change, which may vary from place to place. Thus, in conformal space-time geometry, there is not a particular metric gab, but an equivalence class of metrics where the metrics ğab and gab are considered to be equivalent if there is a smooth positive scalar field Ω for which ğab = Ω gab (R. Penrose, 2012, The Basic Ideas of Conformal Cyclic Cosmology).

conformal; → cyclic; → cosmology.

correlogram
  همبازانش‌نگار   
hambâzâneš-negâr

Fr.: corrélogramme   

A plot showing a summary of correlation at different periods of time.

Correlo-, from → correlation; → -gram.

cosmological
  کیهان‌شناختی، کیهان‌شناسیک   
keyhânšenâxti, keyhânšenâsik

Fr.: cosmologique   

Pertaining or relating to → cosmology.

cosmology; → -al.

cosmological constant
  پایای ِ کیهان‌شناسیک، ~ کیهان‌شناختی   
pâyâ-ye keyhânšenâsik, ~ keyhânšenâxti

Fr.: constante cosmologique   

A term introduced by Einstein into his gravitational → field equations in order to allow a solution corresponding to a → static Universe. The cosmological constant is physically interpreted as due to the → vacuum energy of quantized fields. See also → dark energy.

cosmological; → constant.

cosmological constant problem
  پراسه‌ی ِ پایای ِ کیهانشناختی   
parâse-ye pâyâ-ye keyhânšenâxti

Fr.: problème de la constante cosmologique   

The impressive discrepancy of about 120 orders of magnitude between the theoretical value of the → cosmological constant and its observed value. → Quantum field theory interprets the cosmological constant as the density of the → vacuum energy. This density can be derived from the maximum energy at which the theory is valid, i.e. the → Planck energy scale (1018 GeV). The theoretical vacuum → energy density is (1018 GeV)4 = (1027 eV)4 = 10112 erg cm-3. On the other hand, the observed vacuum energy density is estimated to be about (10-3 eV)4 = 10-8 erg cm-3. There is, therefore, a discrepancy of about 120 orders of magnitude.

cosmological; → constant; → problem.

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