... Tonight's Sky . ... Observing . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... Massive, dim galaxy perplexes scientists . ... It's only recently that astronomers have discovered just how prevalent these dwarf satellite galaxies are, thanks to projects like the Sloan Digital Sky Survey, which imaged large areas of the nighttime sky in greater detail than ever before. ... Only registered members of Astronomy.com are allowed to comment on this article. ...