"Sidereal," he says, to clarify. "A city alone in its own universe; perhaps not so different from here, but all of us brought there know who we are. I have often thought of it as a vacation from my own universe, and after this-" He glances back at the city's center. "-I could use more vacation. And I did not say any farewells to the ones I met there." He gives a small grin. "Something I can do here, though they will by necessity be short or by proxy."