despite the unparalleled abundance on seynorynael , a few marankeil permitted had left that planet to join colonies where their lifespan increased to a thousand or more years , and where they might play a dominant role in their new planet 's social and political activities as a reward for their loyalty ; the trading ships alone had special passes to all worlds , and moving from one world to another was strictly controlled for ordinary citizens , not least by the cost of such journeys .