  This meeting is entitled "A Century of Cosmology." But most of the papers
being given here are based on work done very recently and there is really no
attempt being made to critically review what has taken place in the last 90 or
100 years. Instead, in general the participants accept without question that
cosmology equates to "hot big bang cosmology" with all of its bells and
whistles. All of the theory and the results obtained from observations are
interpreted on the assumption that this extremely popular model is the correct
one, and observers feel that they have to interpret its results in terms of
what this theory allows. No one is attempting to seriously test the model with
a view to accepting it or ruling it out. They are aware, as are the theorists,
that there are enough free parameters available to fix up almost any model of
the type.
  The current scheme given in detail for example by Spergel et al (206, 2007)
demonstrates this. How we got to this stage is never discussed, and little or
no attention is paid to the observations obtained since the 1960s on activity
in the centers of galaxies and what they imply. We shall show that they are an
integral part of a realistic cosmological model. In this paper I shall take a
different approach, showing first how cosmological ideas have developed over
the last 90 years and where mistakes have been made. I shall conclude with a
realistic model in which all of the observational material is included, and
compare it with the popular model. Not surprisingly I shall show that there
remain many unsolved problems, and previously unexpected observations, most of
which are ignored or neglected by current observers and theorists, who believe
that the hot big bang model must be correct.
