Uranus has a tilt of about 98 degrees, essentially rotating on its side. This extreme tilt causes each pole to face the Sun for decades at a time, resulting in extreme seasonal changes. Its day-night cycle is unusual, and seasons last over 20 Earth years.

Uranus’s tilt likely resulted from a massive collision. It has faint rings and many icy moons, and studying it provides clues about how giant planets evolve