When the James Webb Space Telescope launches in 2021, NASA scientists predict they’ll observe phenomena on the ice giants, Uranus and Neptune–the least-explored category of planet in our solar system–that are totally unlike anything we’ve seen. The Neptune we currently know is a dark, cold world, whipped by supersonic winds that can reach up 1,500 miles per hour. More than 30 times as far from the Sun as Earth, Neptune is the only planet in our solar system not visible to the naked eye. Its existence was predicted by mathematics before its discovery in 1846. In 2011, Neptune completed its first 165-year orbit since its discovery.