Pin galaxies were galaxies which existed within the universe of the atom. They were difficult to study as they only had a life span of about one attosecond (a quintillionth of a second). Dastari's people were researching rho mesons as the unstable factor in these galaxies. (TV: The Two Doctors [+]Loading...["The Two Doctors (TV story)"])
One reported to the hermit that some remains of Mictlan technology were leading out into pin galaxies with variant physical laws, but it was nothing that might attract Swimmers. (PROSE: The Taking of Planet 5 [+]Loading...["The Taking of Planet 5 (novel)"])