The five major moons are massive enough to have reached hydrostatic equilibrium, and four of them show signs of internally driven processes such as canyon formation and volcanism on their surfaces.
Lima bulan utama cukup besar telah mencapai kesetimbangan hidrostatik, dan empat dari mereka menunjukkan tanda-tanda didorong secara internal proses seperti pembentukan ngarai dan vulkanisme pada permukaan mereka.