 The aliens, equipped with faster-than-light ships, are amazed that humans dared to cross interstellar space with rockets, having done so only 200 years after inventing radio.Humans do not possess faster-than-light ships, but in order to survive as a species have taken the audacious tactic of using generational starships, in the hopes that their descendants will one day arrive at a new planet.The final lines of the story have the aliens musing about the nature of human civilization and the future of the humans when they learn about the existence of other intelligent life, given their rapid advancement and apparent determination.