  By studying the present cosmological data, particularly on CMB, SNeIA and
LSS, we find that the future fate of the universe, for simple linear models of
the dark energy equation-of-state, can vary between the extremes of (I) a
divergence of the scale factor in as little as 7 Gyr; (II) an infinite lifetime
of the universe with dark energy dominant for all future time; (III) a
disappearing dark energy where the universe asymptotes as $t \to \infty$ to
$a(t) \sim t^{2/3}$ {\it i.e.} matter domination. Precision cosmological data
hint that a dark energy with equation of state $w = P/\rho < -1$ and hence
dubious stability is viable. Here we discuss for any $w$ nucleation from
$\Lambda > 0$ to $\Lambda = 0$ in a first-order phase transition. The critical
radius is argued to be at least of galactic size and the corresponding
nucleation rate glacial, thus underwriting the dark energy's stability and
rendering remote any microscopic effect.
