(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A closed Friedmann universe contains a single perfect fluid with an equation of state of the form [tex]p=w\rho c^2[/tex]. Transforming variables to conformal time [tex]\tau[/tex] using [tex]dt=a(t)d\tau[/tex], show that the variable [tex]y=a^{(1+3w)/2}[/tex] is described by a simple harmonic equation as a function of [tex]\tau[/tex]. Hence argue that all closed Friedmann models with a given equation of state have the same conformal lifetime.

2. The attempt at a solution

Please give me a starter. I haven't got a clue...

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# Conformal time closed Friedmann universe

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