  Measurements of the SNe Ia Hubble diagram which suggest that the universe is
accelerating due to the effect of dark energy may be biased because we are
located in a 200-300 Mpc underdense "void" which is expanding 20-30% faster
than the average rate. With the smaller global Hubble parameter, the WMAP-5
data on cosmic microwave background anisotropies can be fitted without
requiring dark energy if there is some excess power in the spectrum of
primordial perturbations on 100 Mpc scales. The SDSS data on galaxy clustering
can also be fitted if there is a small component of hot dark matter in the form
of 0.5 eV mass neutrinos. We show however that if the primordial fluctuations
are gaussian, the expected variance of the Hubble parameter and the matter
density are far too small to allow such a large local void. Nevertheless many
such large voids have been identified in the SDSS LRG survey in a search for
the late-ISW effect due to dark energy. The observed CMB temperature decrements
imply that they are nearly empty, thus these real voids too are in gross
conflict with the concordance LCDM model. The recently observed high peculiar
velocity flow presents another challenge for the model. Therefore whether a
large local void actually exists must be tested through observations and cannot
be dismissed a priori.
