HST observed two bright spots located in the northern and southern hemispheres, near ± 50° latitude, which is exactly the boundary between the open and closed field lines of the Ganymedian magnetosphere (see below).
HST observou dúas manchas brillantes localizadas no hemisferio norte e sur, preto dos ± 50° de latitude, o cal é exactamente a fronteira entre o campo liñas abertas e pechadas da magnetosfera de Ganímedes (véxase máis abaixo).