"Never heard of IOPSA." She's ignoring the question about Virginia entirely for the moment, because it's easier than telling him that she's from the last city on Earth, as far as anyone knows. That Virginia did exist, but probably doesn't anymore.

"Anyway, the running theory is that this is sort of like...a mini-plane, created and sustained by the Captain. That's why there's nothing living in the ocean, and no bottom anyone's been able to reach. He didn't think to put any animals or seaweed or plankton or anything down there. Or seagulls in the sky. Or things like that."