# dark energy takes over...

29 May 2013What possibilities are there for defining the moment where the Universe switches from matter domination to dark energy domination? The two most obvious choices would be the instant \(a\) where the density parameters are equal, \(\Omega_m(a) = \Omega_\Lambda(a)\), or perhaps when the deceleration parameter changes sign, \(q(a)=0\)… How would you define it and what numerical values for \(a\) would you get with the two above definitions?

math bonus question: can you derive the Taylor expansion of the logarithm using the geometric series of \(1/(1+x)\)?