 What do the characters refer to as "the world?"
But something soft had cushioned the impact—something which had come into being just for the moment and then abruptly passed into non-being again, something which was as impalpable as air. True, this was the only case of its kind, the exception to the rule, but it proved the world was not perfect. You can find several of them under 'astronomy,' with a cross-reference under 'stars.' Something big and round, all grays and greens and browns, and something for which Rikud had no name.
 Their ship, which is all they have ever known.
 Their ship, which is all they have ever known.  The men's quarters, which is all they have ever known.  The planet they are preparing to plummet onto.  They use it as a general term for the "universe."