deceleration parameter

(dee-sel-ĕ-ray -shŏn) Symbol: q ₀. The rate at which the expansion of the Universe changes with time as a result of self-gravitation. It is dimensionless and can be given in terms of the cosmic scale factor, R: q ₀ = –R (d²R /dt ²)/(dR /dt )²

Values of q ₀ less than 0.5 are associated with an ever-expanding open Universe; values exceeding 0.5 imply that the Universe is closed and will collapse at a finite time in the future. If q ₀ is equal to 0.5 then the Universe is infinite and space is Euclidean. See also mean density of matter; Universe.

单词	deceleration parameter
释义	deceleration parameter deceleration parameter (dee-sel-ĕ-ray -shŏn) Symbol: q ₀. The rate at which the expansion of the Universe changes with time as a result of self-gravitation. It is dimensionless and can be given in terms of the cosmic scale factor, R: q ₀ = –R (d²R /dt ²)/(dR /dt )² Values of q ₀ less than 0.5 are associated with an ever-expanding open Universe; values exceeding 0.5 imply that the Universe is closed and will collapse at a finite time in the future. If q ₀ is equal to 0.5 then the Universe is infinite and space is Euclidean. See also mean density of matter; Universe.
随便看	stibic stibiconite stibide stibine stibiocolumbite stibious stibitz, george robert stibium stibnate stibnite stibnites stibnium stibocaptate physical delivery physical delivery access unit physical delivery request form physical delivery service physical delivery system physical demand assessment physical demand characteristics physical demand level physical demands information form physical dependence physical dependency physical deposition technique