The way that Gilbert and Rooke think about the stars and the sky is indicative of how they think about community in terms of scale. Gilbert cares only for what he can see and what's in front of him—he wants control over the known, which, by necessity, means that his community is one of a relatively small scale. Rooke, on the other hand, still believes that he's a very small and insignificant part of a whole. By mapping stars, he brings them more fully into his community, but recognizing that the unseen stars are there acknowledges that there are larger forces that he can't necessarily see or comprehend.