... Tonight's Sky . ... Gravitational wave search provides insights into galaxy evolution and mergers . ... Hubble images detail galactic "mergers and acquisitions" . ... Astronomers believe that galactic mergers so shake up young galaxies that their central black holes experience the equivalent of a smorgasbord. ... The galaxies all are located 3.5 billion light-years away, but Hubble can resolve details just a few thousand light-years across, which enables astronomers to see structural details. ...