What would you say if your wacky uncle asked you if you would like to be beamed into space in a thought bubble? You'd say, “When do I leave?” of course, just like Gedanken, the adventurous girl in this story. Soon she's speeding across the universe trying to help her uncle answer some knotty questions, such as What is time? How big is space? And where does gravity come from? Along the way she also discovers how to get heavier without getting fat, how to live forever without knowing it, and the weird things that can happen when you go really, really fast.