An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 4 Search : accelerating
accelerating
  شتابنده   
šetâbandé (#)

Fr.: en accélération   

Moving or proceeding with → acceleration; e.g. → accelerating system; → accelerating Universe.

Verbal adj. from → accelerate.

accelerating expansion of the Universe
  سپانش ِ شتابنده‌ی ِ گیتی   
sopâneš-e šetâbande-ye giti

Fr.: expansion accélérée de l'Univers   

accelerating Universe.

accelerating; → expansion; → Universe.

accelerating system
  راژمان ِ شتابنده   
râžmân-e šetâbandé

Fr.: système en accélération   

A material system that is subject to a constant force in each and every one of its instantaneous points of trajectory.

accelerating; → system.

accelerating Universe
  گیتی ِ شتابنده   
giti-ye šetâbandé (#)

Fr.: univers en accélération   

The deduction based on the observation that the most distant → Type Ia supernovae are fainter than that expected from their → redshifts in a matter-only dominated expanding Universe. The faintness is attributed to larger distances resulting from an accelerating Universe driven by presence of a new component with strongly negative pressure. This component that makes the Universe accelerate is named → dark energy. The deceleration or acceleration of an expanding Universe, given by the general relativistic equation, is: R../R = -(4/3)πGρ(1 + 3w), where R is the linear → cosmic scale factor of the expanding Universe, G the → gravitational constant, ρ the mean density of the Universe, and w the → equation of state parameter representing dark energy. The expansion accelerates whenever w is more negative than -1/3. The Nobel Prize in Physics 2011 was awarded to the initiators of this concept, Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess, for their discovery of the accelerating expansion of the Universe through observations of distant supernovae. See also the original paper: Perlmutter et al. 1999, ApJ 517, 565.

accelerating; → universe.