The spaceship Chinook has jumped at random through a T machine field and is in an unknown planetary system. The bearings of other galaxies show this system to be about 500 light years from Sol towards Hercules. This makes Deneb and the Orion Nebula identifiable.
The new sun is a red dwarf with five planets, none like Earth. The Chinook crew detect artificial radio signals from a gas giant which they name Danu. The ship's boat investigates and finds inhabitants like flying whales with whom they exchange music. The Danaans have instruments of metal which could not have been mined on a planet whose surface is hot liquid hydrogen so must have been donated by the Others who constructed the T machines.
10 to 20 billion years ago. Dark empty space with no stellar background. Gas clouds collapsing into galaxies. One supergiant star, 50,000 times as luminous as Sol, has been big enough to form this early but with just a single companion, not as part of a cluster.
The Others must have originated even earlier when an unusual concentration of elements in a nebula generated a star with life-bearing planets.
Bearings of other galaxies and shape of home galaxy indicate thousands of light years from Earth, same era. Chinook has emerged near a star temporarily green because leaving the main sequence and shortly to expand into a red giant, about ten billion years old but containing enough heavy elements to indicate that it might have formed near a supernova.
The crew detect repetitive radio signals from an old, dying planet they name Pandora. A force field protects uninhabited buildings with an empty spacecraft base and the radio transmitter. A landing party find ruins and three-eyed animals but is attacked by savages and leaves. Theory: the old race has left but sometimes returns to guide the savages who have evolved during the planet's decline.
Millions of years futureward, in the same spiral arm, thousands of light years closer to galactic centre. A "...whirling sword of light..." is a pulsar/neutron star with a quasi-solid quaking surface under a six millimeter atmosphere. (1) A curved shell around the T machine shields emerging spacecraft from the destructive pulsar ray. Near the T machine is a station for visitors of different species. Chinook's holothete, Joelle, a human being linked to a computer, communicates in binary code with the station which informs her that, on the pulsar's surface, interactions between raw nuclei generate self-replicating, thus living, structures lasting for mere seconds but so energetic that they experience the equivalent of more than a century so that to them human beings would be as inert as stones.
The station guides the holothete to contact with the Oracle, a self-aware Others' artifact on the pulsar, which:
is as intelligent as a human being in holothesis;
counsels pulsar life ("...the star dwellers..." (2)) to whom it is a gigantic shrine;
records and plays back pulsar history;
mediates between pulsar life and visitors to the station;
possibly modulates strong nuclear forces to communicate quasi-telepathically with the star dwellers;
communicates, possibly by quark beams, with the station which relays by radio etc;
slows or speeds communications as appropriate for receivers.
The star dwellers:
had no idea of a sky in the pulsar's radiation haze;
exploring through a billion generations, found the Fire Fountains;
to explore the Fountains, climbed thirteen millimeter high mountains, which last as long as a terrestrial year, through many generations and civilizations;
reaching the top of the atmosphere, tunneled up through a mountain;
a million lifetimes later, saw the stars through a transparent dome.
With knowledge from the Oracle, Joelle plans a route between T machines to take Chinook to the frontier where the Others still construct new T machines.
(1) Anderson, Poul, The Avatar, London, 1985, p. 319.
(2) ibid., p. 330.