A hexagon-shaped atmospheric phenomenon first spotted on Saturn by Voyager 1 and Voyager 2 has intrigued scientists since the 1980s. More recently, NASA's Cassini mission has periodically observed the hexagon and its embedded strong eastward jet that rotates at 120 meters per second. Scientists believe that the persistence of the hexagon could put to rest the oft-debated question of the length of Saturn's rotational period.