Of, relating to, or based on analogy; expressing or implying analogy.
anisotropic homogeneous cosmological model
model-e keyhânšenâxti-ye hamgen o nâ-izogard
Fr.: modèle cosmiologique homogène mais anisotrope
A solution to Einstein's theory of → general relativity that is spatially homogeneous but allows for rotation and/or shear. See also → Bianchi cosmological model.
→ anisotropic; → homogeneous; → cosmological; → model.
Bianchi cosmological model
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.
Pertaining or relating to → cosmology.
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
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.
durâ-ye keyhânšenâsik, ~ keyhânšenâxti
Fr.: distance cosmologique
The distance to a remote galaxy based on its redshift assuming that the redshift is caused by the → Doppler effect and reflects the general expansion of the Universe.
→ cosmological; → distance .
Fr.: époque cosmologique
→ cosmological; → epoch.
model-e keyhânšenâsik, ~ keyhânšenâxti
Fr.: modèle cosmologique
A mathematical description of the Universe, based on observation, which tries to explain its current aspect, and to describe its evolution during time.
→ cosmological; → model.
parvaz-e keyhânšenâsik, ~ keyhânšenâxti
Fr.: principe cosmologique
The → hypothesis that on → large scales the → Universe is → isotropic and → homogeneous, that is, it appears the same at all places and, from any one place, looks the same in all directions. See also → perfect cosmological principle.
sorxkib-e keyhânšenâsik, ~ keyhânšenâxti
Fr.: décalage vers le rouge cosmologique, redshift ~
The → redshift of a remote object (galaxy, quasar, supenova) due to the expansion of the Universe.
→ cosmological; → redshift.
current cosmological epoch
zime-ye keyhânšenâxti-ye konuni
Fr.: époque cosmologique actuelle
The → Universe at the → redshift z = 0.
→ current; → cosmological; → epoch.
guyik, gyuiki, guyikvâr
1) According to or agreeing with the principles of logic.
Fr.: connecteur logique
A symbol that can be combined with one or more → sentences in order to form a new sentence. For example "and" (∧), "or" (∨) "not" (¬), "if-then" (→), and "iff" (⇔).
→ logical; → connective.
Fr.: logiquement équivalent
Describing two → compound propositions → if and only if they have the same → truth table.
→ logical; → equivalent.
Fr.: observation météorologique
Evaluation or measurement of one or more meteorological elements.
Meteorological, of or pertaining to → meteorology; → observation.
Fr.: observatoire météorologique
A scientific establishment dedicated to making precise and detailed meteorological observations and to studying and forecasting atmospheric phenomena by means of special equipments.
Meteorological, of or pertaining to → meteorology; → observatory.
Milne cosmological model
model-e keyhânšenâxti-ye Milne (#)
Fr.: modèle cosmologique de Milne
Same as → Milne Universe.
→ Milne Universe; → cosmological; → model.
Of or relating to → morphology. Same as morphological
→ morphologic; → -al.
radebandi-ye rixtšenâxti (#)
Fr.: classification morphologique
A classification scheme of galaxies based on their apparent shape. → Hubble classification.
→ morphological; → classification.