Astronomers have discovered Andromeda XXXVI, an ultra-faint, dark matter-rich satellite of Andromeda Galaxy. This ancient system may be a fossil from the early universe, helping scientists study galaxy formation and dark matter.​Astronomers have discovered Andromeda XXXVI, an ultra-faint, dark matter-rich satellite of Andromeda Galaxy. This ancient system may be a fossil from the early universe, helping scientists study galaxy formation and dark matter.  ​ science