This revelation about the LMC might help solve a long-standing cosmological mystery, as predicting the number of satellite galaxies that surround galaxies like the Milky Way is something of a challenge. These small systems are believed mostly to have formed early, and so how many there are is very sensitive to details of the make up of the Universe, especially to what we assume about the amount of dark matter and how it behaves.
Most astronomers believe that, although it is mysterious, there is much more dark than ordinary matter, but for years models with plenty of dark matter have predicted more satellite galaxies than we see. More sensitive surveys have found fainter systems, but this new result may suggest they’ve had more complex lives than we would otherwise expect. If mergers of satellites are common, we need to do more than just count them – we need to understand their histories too.