 For example, they visit the star Deneb, which is the origin of Earth humans, as well as many other humanoid races across the Solar System and beyond.The series was originally set in 1990; as the series progressed, Hamilton quickly stopped using exact dates (except as "in the past" as in the voyages of the astronauts who first landed on most of the other planets of the Solar System), sticking with a series continuity.In later stories, if the date was asked or revealed, it was done so discreetly.