Readers Respond to the January 2021 Issue
Scientific American Letters to the editor from the January 2021 issue of Scientific American BIG OLD GALAXIES Arianna S. Long's “Too Big for the Universe” describes ancient galaxy clusters that are surprisingly massive for their early age. Could this observation be related to how supermassive black holes in the centers of some galaxies have grown so big so quickly that their size is also difficult to explain? K. CYRUS ROBINSON Tampa, Fla. While I was reading Long's article, I happened to be twirling a glass of iced tea and noticed that the bubbles on top had centered in a cluster that l...
Source: scientificamerican.com