To answer questions: 1) We still need dark matter. This mostly focuses on small satellite galaxies. Not galactic rotation, galaxy cluster interaction, or light

To answer questions: 1) We still need dark matter. This mostly focuses on small satellite galaxies. Not galactic rotation, galaxy cluster interaction, or light lending though Galaxy Clusters. 2) The main interesting tidbit is that it seems the density of Galaxies in the Universe has changed sharply in the past 1billion years. Which may lend more data points to Dark Energy/Inflation models.