Age of a flat barotropic matter-vacuum universe
= Age of a flat barotropic matter-vacuum universe
{title2=$t_0=\dfrac{2\operatorname{artanh}\sqrt{\Omega_{\Lambda0}}}{3(1+w)H_0\sqrt{\Omega_{\Lambda0}}}$}
The <flat barotropic matter-vacuum solution> has $H_\Lambda/H_0=\sqrt{\Omega_{\Lambda0}}$ and therefore the displayed age, measured from its <Big Bang>. At fixed $H_0$ and <density> fractions it is $1/(1+w)$ times the dust-plus-vacuum age. Its $w=0$ case is the <age of a flat matter-Lambda universe>.