> After billions of years, I would expect all planets be attached (gravitationally) to a star, shouldn't they? Planets are formed around stars, but some escape

> After billions of years, I would expect all planets be attached (gravitationally) to a star, shouldn't they? Planets are formed around stars, but some escape due to gravitational slingshotting etc.. Some of those might be caught again, but why would you think all are?