$\rho \left(a\right)$

$a\left(t\right)$

$H\left(t\right)$

$1/\left(aH\right)$

$w\equiv p/\rho$

Λ

constant

e^Ht

constant

$a^{-1}$

−1

Radiation

$a^{-\text{4}}$

t^1/2

1/(2t)

$a$

1/3

Matter

$a^{-\text{3}}$

t^2/3

2/(3t)

$a^{1/2}$

0