“I like knowing there’s certain laws in the universe, Ayla’s father had said once, a very long time ago, before everything. You can’t count on much. Can’t trust most things to stay solid. But there is always some sort of force at work. Even way out there past the sky, so far away that we can’t even imagine it, things work the same. Your mother would explain it better. Everything is just bodies in motion, bodies in orbit, just like here. Pushing and pulling. You know what that’s called? The law of falling.”