While many open world zones will not have open pvp, some zones will.
PVP enabled zones will typically be in areas that contain high rarity monsters and resource nodes.
Players may wage war against other player's planets.
Players can hire other players to help attack or defend another player's planet.
Enemy players can destroy a city's defenses and take resources based upon the level of ecosystem and rarity of the planet.
Protective barriers will be available. These can be used to nullify and prevent any enemies from waging warfare against a player's planet for a set duration of time.
Players will have the freedom to build out defensive and military-based building resources which can be leveled up and explored to defend the Homebase and prepare to wage war against other enemy Homebase planets.