The Big Empty

摘要

YOU might ask WHY we would do a cover story on cosmic voids —those stupendously vast, largely galaxy-free Saharas of space. After all, astronomy is all about observing things, not nothings, right? Even if you wanted to look there, as a zealous coterie of professional astronomers does, it's not a walk in the park. As one of these folks wryly notes in our article on page 12, "Observing empty space is very hard."