An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



Number of Results: 10 Search : cosmology
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.

keyhânšenâsi (#)

Fr.: cosmologie   

The science of the origin, structure, and evolution of the Universe including the origin of galaxies, the chemical elements, and matter.

Cosmology, from → cosmo- + → -logy.

Keyhânšenâsi, from keyhân, → cosmos, + šenâsi, → -logy.

fractal cosmology
  کیهانشناخت ِ برخالی   
keyhânšenâxt-e barxâli

Fr.: cosmologie fractale   

The postulate that the concentrations of matter in the Universe follow a → fractal structure over a wide range of scales.

fractal; → cosmology.

geocentric cosmology
  کیهان‌شناسی ِ زمین‌مرکزی   
keyhân-šenâsi-ye zamin-markazi (#)

Fr.: cosmologie géocentrique   

A model of the Universe in which the Earth is centrally located and the Sun, planets, and stars revolve around the Earth.

geocentric; → cosmology.

heliocentric cosmology
  کیهان‌شناسی ِ هورمرکزی   
keyhânšenâsi-ye hurmarkazi (#)

Fr.: cosmologie héliocentrique   

A model of the Universe in which the Sun was centrally located.

heliocentric; → cosmology.

hierarchical cosmology
  کیهان‌شناسی ِ پایگانی   
keyhânšenâsi-ye pâygâni

Fr.: cosmologie hiérarchique   

A cosmology characterized by clustering of galaxy clusters in increasingly larger systems.

hierarchical; → cosmology.

Newtonian cosmology
  کیهان‌شناسی ِ نیوتنی   
keyhânšenâsi-ye Newtoni

Fr.: cosmologie newtonienne   

The use of → Newtonian mechanics to derive homogeneous and isotropic solutions of → Einstein's field equations, which represent models of expanding Universe. The Newtonian cosmology deviates from the prediction of → general relativity in the general case of anisotropic and inhomogeneous models.

Newtonian; → cosmology.

observational cosmology
  کیهان‌شناسی ِ نپاهشی   
keyhânšenâsi-ye nepâheši

Fr.: cosmologie observationnelle   

The application of observational data to the study of the Universe as a whole.

observational; → cosmology.

plasma cosmology
  کیهان‌شناسی ِ پلاسمایی   
keyhânšenâsi-ye plâsmâyi

Fr.: cosmologie plasma   

An alternative cosmology, initially conceived by Hannes Alfvén in the 1960s, that attempts to explain the development of the visible Universe through the interaction of electromagnetic forces on astrophysical plasma. Like the steady state model, plasma cosmology hypothesizes an evolving Universe without beginning or end.

plasma; → cosmology.

standard cosmology
  کیهان‌شناسی ِ استانده   
keyhânšenâsi-ye estândé

Fr.: cosmologie standard   

The conventional → Big Bang model, which is based on two assumptions: the → cosmological principle of homogeneity and isotropy leading to the → Robertson-Walker metric, and → Einstein's field equations of general relativity along with familiar properties of matter. This model is a remarkably successful operating hypothesis describing the evolution of the Universe from 1/100 second after the initial event through to the present day. It provides explanations for several basic problems such as: → Hubble's law of recession of galaxies, interpreted in terms of the expansion of the Universe; the abundances of the → light elements, in excellent agreement with the predictions of → primordial nucleosynthesis; and the thermal spectrum and angular isotropy of the → cosmic microwave background (CMB) radiation, as expected from a hot, dense early phase of expansion. For a non-standard model, see → ekpyrotic Universe.

standard; → cosmology.