The skeleton of space is constantly shifting. The natural tubes connecting each mass in space, in all their oddness, are anchored rather oddly. Note the connections between a star and its most distant planets or binary companions- they split and fray, spilling their contents in the nearby void rather than approaching their destinations properly. If you've experienced this, you may well know that this is a result of the slow-but-present movement of the connected bodies- those tubes are, for lack of a better term, fragile. You may also understand how the tubes weaken with distance, requiring ever-more-advanced (or at least powerful) drives to cross the gap between distant stars. And if you're an astronomer... you know the stars move. They orbit the galactic core, or are flung into the distance. Over relatively short timescales, their relative distances vary by full light-years. And of course the stars exert their gravitational pull on each other- as a result, that aching skeleton is constantly disconnecting and reconnecting.
