  In a recent striking discovery, Dunlop {\bf \it et al} observed a galaxy at
redshift z=1.55 with an estimated age of 3.5 Gyr. This is incompatible with age
estimates for a flat matter dominated universe unless the Hubble constant is
less than $ 45 kms^{-1}Mpc^{-1}$. While both an open universe, and a universe
with a cosmological constant alleviate this problem, I argue here that this
result favors a non-zero cosmological constant, especially when considered in
light of other cosmological constraints. In the first place, for the favored
range of matter densities, this constraint is more stringent than the globular
cluster age constraint, which already favors a non-zero cosmological constant.
Moreover, the age-redshift relation for redshifts of order unity implies that
the ratio between the age associated with redshift 1.55 and the present age is
also generally larger for a cosmological constant dominated universe than for
an open universe. In addition, structure formation is generally suppressed in
low density cosmologies, arguing against early galaxy formation. The additional
constraints imposed by the new observation on the parameter space of $h$ vs
$\Omega_{matter}$ (where $H= 100 h kms^{-1}Mpc^{-1}$) are derived for both
cosmologies. For a cosmological constant dominated universe this constraint is
consistent with the range allowed by other cosmological constraints, which also
favor a non-zero value.
