  The idea of the universe with a mirror sector having all particles and forces
identical to those in the familiar sector has been proposed in the context of
neutrino physics as well as superstring theories. Assuming that all the quark
and charged lepton masses in the mirror universe are scaled by a common factor,
$\zeta$, as is required in one interpretation of the neutrino data, we
investigate domains of the parameter $\zeta$ where physical conditions are
favorable for cooling in the age of the universe that can lead to the formation
of compact structures given the initial condition $\Omega_B
=\Omega_{\tilde{B}}$ ($\tilde{B}$ denoting the mirror baryon). In particular we
ask whether there is a region in $\zeta$-space for which primordial Jeans mass
mirror clouds cannot cool in the present age of the universe. We find that for
most of the area of interest in the parameter space, atomic hyperfine structure
cooling is effective in a time period short compared to the age of the universe
but long compared to the free fall time for globular-sized objects expected on
the basis of simple Jeans length analysis.
