The TNO orbits in a plane that’s tilted 110 degrees to the plane of the solar system. What’s more, it swings around the sun backwards unlike most of the other objects in the solar system. With this in mind, the team that discovered the TNO nicknamed it “Niku” after the Chinese adjective for rebellious. To grasp how truly rebellious it is, remember that a flat plane is the signature of a planetary system, as a star-forming gas cloud creates a flat disk of dust and gas around it. “Angular momentum forces everything to have that one spin direction all the...