https://wiki.eveuniversity.org/COSMOS
They are basically what other games call quests or storylines.
And no, the Guristas will not take over the constellation or something. In the grand scheme of things so far (CCP has been trying to change this for years now) the sovereignty states of all systems except for faction warfare systems are set in stone. For the foreseeable future, this constellation will remain in Caldari State hands.