Stations

The Boat Of A Million Years.

Starfarers report their discoveries to rendezvous stations that they have established orbiting certain stars. Stations beam information to each other and to ships in transit. Also, ships visit the stations periodically because it is impossible to transmit data continuously to any ship travelling at any velocity. Information about Xenogaia transmitted by the Alloi to the nearest rendezvous has caused another race to decide to visit Tritos.

But these are organic space travelers. Usually, a civilization that wants to learn about life in other planetary systems but also to remain at home sends robot probes only about a light-century away for reasons of distance. However, they also send such probes further afield to:

other civilizations;

unusual stars;

star-generating nebulae;

supernovae;

black holes;

the galactic core.

In all but the first case, robot probes, having arrived at their goal, beam invitations and wait to be joined by other robots. At this point, Anderson makes a conceptual leap that is more fully explained only by reading Harvest Of Stars and Genesis. In the core civilizations, machine intelligence becomes superior and therefore displaces organic intelligence. Machines contemplate abstractions. Organisms usually become extinct but occasionally survive only to pursue enjoyment or "enlightenment" but not empirical knowledge. Why? Some machines and men can still seek and venture outward, surely?

In any case, the Survivor-Alloi alliance intends to buck this trend. 

Outward, with Poul Anderson's characters into the universe...