... Tonight's Sky . ... Mysterious magnetar boasts one of strongest magnetic fields in universe . ... Scientists using the European Space Agency s (ESA) XMM-Newton space telescope have discovered that a curious dead star has been hiding one of the strongest magnetic fields in the universe all along, despite earlier suggestions of an unusually low magnetic field. ... We now have a new tool to probe the magnetic fields of other magnetars, which will help constrain models of these exotic objects. ...