In the description of the formation of stars and galaxies from a hydrogen cloud or clouds the theory proposed as part of the Big Bang narrative is that tiny variations in the CMBR has resulted in a perfect separation of galaxies and the intergalactic void. This is the part of the description that I find difficult. With billions of galaxies forming from a number of hydrogen clouds which are affected by tiny and irregular variations in the CMBR I would have expected (in this model) that some areas of space would have an isolated cloud of hydrogen gas which would collapse to form a single star and be seen as a supernova. The fact that no such intergalactic stars or supernovae are observed does seem to undermine the Big Bang descripion of galaxy formation. I think we should be looking for an alternative explanation for galaxy formation which starts with a the formation of the central black-hole and that the cloud of hydrogen gas formed around the black hole leads to star formation only within the halo of the galaxy. https://www.academia.edu/5009126/The_evolution_of_the_universe Richard