For quite a while now I've been focusing on expanding my colonies for the sake of having easy access to fuel. I've been setting my colonies down only on planets with 10k resources or more. Even so, I note that the amount of resources my colonies gather is more than the amount noted in the planet's information (which, also notably, never seems to deteriorate). Are the resources limitless? If so, what's the difference between a low number and a high one?