-only UniverseIn this case
so
![[Graphics:DzDangleSummarygr34.gif]](DzDangleSummarygr34.gif)
which is real if
. If
then the universe is contracting at early times, reaches a minimum size, and starts to re-expand again. The redshift at turnaround,
, is the maximum value of the redshift, larger values are not physically meaningful.