An Etymological Dictionary of Astronomy and Astrophysics

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فرهنگ ریشه‌شناختی اخترشناسی-اخترفیزیک

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acceleration parameter
  پارامون ِ شتاب  
pârâmun-e &#353etâb
Fr.: paramètre d'accéleration  

A measure of the departure from a constant rate of the acceleration of the Universe, expressed by:
q(t) = R(t)R ..(t)/R .2(t), where R(t) represents the size of the Universe at time t. Traditionally, a negative sign is inserted in the above equation for the → deceleration parameter.

See also: → acceleration; → parameter.