Inside The Cloud Universe

Space is never completely empty. In "Starfog," Poul Anderson imagines a volume of space full of gas and dust illuminated by hundreds of thousands of closely packed stars at every stage from condensation to explosion. Gas, condensing into stars, is enriched by novas and renewed when the cluster's eccentric orbit approaches the galactic center.

Standing on the bridge of his spaceship, Daven Laure sees clouds and colors glowing, streaming, eddying, piling into cliffs and darkening into grottoes. He traverses not apparent emptiness but landless cloudscapes, hears sounds, feels vibrations and remembers fire and ice meeting in the Void of Norse mythology.

His computer remarks that the external view is an illusion:

the interstellar medium is not as dense as a planetary atmosphere but appears so because absorption and reflection effects are cumulative over light years;
the swirling appears accelerated because the ship is under hyperdrive;
space does not shine - excited atoms fluoresce;
the sounds heard are from instruments within the ship;
quantum micro-jumping across variable magnetic fields, the ship interacts with them and thus seems to be buffeted by tangible currents.