Bryson stresses that humans know very little about the universe by discussing phenomena in space that we have little to no grasp on—such as dark matter, which permeates everything but is undetectable by humans. Whether scientists scale up (to the universe at large) or scale down (to the tiniest particles that exist), the picture is increasingly complex and mysterious. All of this implies that the harder and closer scientists look, the more they realize that there is so much that humans don’t know and may never know.