Material content of the Universe: meeting summary

The proceedings of a discussion held in October 1985 are summarized. Fourteen papers were presented, all of which are indexed separately. The discussion considered the large-scale distribution of mass in the Universe and, in particular, whether the mean value might agree with the Einstein-de Sitter cosmological model. Also, it considered the composition of mass as a function of position and whether exotic matter might be significant in some regions. Also, the cosmic evolution of the mass distribution and composition was discussed. Many clues were presented but no general agreement on how they fit together was reached. The observational evidence for the presence of dark matter was carefully and sceptically reviewed. Either Newtonian mechanics fails or there are regions where the mass exceeds that expected from star light. If dark matter is present can it be accounted for by low-luminosity stars or is it an exotic form. The evidence and theories as presented at the discussion are summarized. (UK)