  Dark energy and the accelerated expansion of the universe have been the
direct predictions of the distant supernovae Ia observations which are also
supported, indirectly, by the observations of the CMB anisotropies,
gravitational lensing and the studies of galaxy clusters. Today these results
are accommodated in what has become the `concordance cosmology': a universe
with flat spatial sections t=constant with about 70% of its energy in the form
of Einstein's cosmological constant \Lambda.
  However, we find that as more and more supernovae Ia are observed, more
accurately and towards higher redshift, the probability that the data are well
explained by the cosmological models decreases alarmingly, finally ruling out
the concordance model at more than 95% confidence level. This raises doubts
against the `standard candle'-hypothesis of the supernovae Ia and their use to
constrain the cosmological models. We need a better understanding of the entire
SN Ia phenomenon in order to have cosmological consequences from them.
