Stars Between Galaxies

In Poul Anderson's Tau Zero, a spaceship crossing intergalactic space passes a red dwarf star with planets. The astronomer on the ship does not know whether the red dwarf had originated in the normal way within a galaxy or in some unknown way between galaxies.

Anderson's World Without Stars (New York, 1966) answers this question:

hydrogen clouds condensed into galaxies;
smaller condensations became intergalactic star clusters which, however, did not endure because -

(i) their giants went supernova,
(ii) cosmic expansion dispersed matter, thus preventing any further star formation,
(iii) galactic gravitation broke the clusters up;

thus, only the long living red dwarfs were left.

Captain Argens, en route to a planet of such a star, explains all this to his two new crew members and thus to us. I thought that two spacemen would not need to be told how stars formed. Sure enough, Rorn complains:

" 'Please...Valland and I do know elementary astrophysics.' " (p. 19)

Valland agrees that he does but is beginning to realize the implications in intergalactic space: old stars and planets that are metal-poor because supernova enrichment stopped early but with lighter elements and life, including intelligent races that might have needed millions of years to industrialize and therefore have learned different things along the way.

These Yonderfolk can travel only to the galactic rim and then only with heavy radiation screening because the radiation level within any galaxy would kill them. Valland wonders whether they have natural immortality but Argens points out that quantum processes, viruses and chemicals can also mutate cells. Valland's speculation echoes Anderson's story "What Shall It Profit?" in which a man is made immortal by shielding him from all radiation in a very restricted environment deep underground. He is physically immortal but mentally undeveloped, an experimental dead end.