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Cosmological models — Hobson, Efstathiou & Lasenby
Physics · flat-radiation-only-friedmann-results
Problem For the spatially flat, radiation-only, Friedmann model, prove the following useful results:
a ( t ) = ( t t 0 ) 1 / 2 , H ( t ) = 1 2 t = H 0 ( 1 + z ) 2 , q 0 = 1 , ρ r ( t ) = 3 32 π G t 2 . a(t) = \left(\frac{t}{t_0}\right)^{1/2}, \qquad H(t) = \frac{1}{2t} = H_0(1+z)^2, \qquad q_0 = 1, \qquad \rho_r(t) = \frac{3}{32\pi G t^2}. a ( t ) = ( t 0 t ) 1/2 , H ( t ) = 2 t 1 = H 0 ( 1 + z ) 2 , q 0 = 1 , ρ r ( t ) = 32 π G t 2 3 . Browse the problem library