Has yesterday's announcement of seven small exoplanets left you wondering how astronomers decide which planets to call "habitable"? Come with our science editor as she explores (and agonizes over) the question.
Breaking news! This little star has seven -- count 'em, SEVEN -- potentially rocky planets. Three are in the habitable zone, but all of them might be able to (at least sometimes) have liquid water. Maybe. We don't know yet!