Spatially flat FLRW metric
= Spatially flat FLRW metric
{c}
In Cartesian comoving coordinates and signature $(-,+,+,+)$, a spatially flat FLRW universe has
$$
ds^2=-c^2dt^2+a^2(t)(dx^2+dy^2+dz^2).
$$
= Spatially flat FLRW metric
{c}
In Cartesian comoving coordinates and signature $(-,+,+,+)$, a spatially flat FLRW universe has
$$
ds^2=-c^2dt^2+a^2(t)(dx^2+dy^2+dz^2).
$$