Is there any point in exploring systems that do not have a mission associated with them, besides resource gathering? For example are there any hidden side quests or random encounters to be found?
EDIT: To be more clear, are there any quests or random encounters which are not previously referred to or marked in any way, and thus can only be found by scanning planets? I have "found" a couple of missions by scanning planets but in each case the mission location was already marked on the system map.