In the Lambda-CDM model, the density of galaxies decreases due to the expansion of the universe, but it does not completely vanish. The discussion highlights a misconception about galaxies disappearing; while they may become too dim to observe, their light continues to reach observers. The book "A Universe from Nothing" by Lawrence Krauss discusses the future visibility of galaxies, suggesting that the number of visible galaxies will diminish due to accelerated expansion. Participants seek references or papers that calculate these effects, emphasizing the importance of understanding the distinction between density and visibility. Overall, the conversation centers on the implications of cosmic expansion on galaxy visibility and density.