In our solar system, the planet whose axis is most tilted to its orbit is Uranus, a distant, blue-green gas giant. Its extreme tilt of 97.86 degrees means that each pole of the planet faces the Sun directly for about one quarter of its 84-year orbit.

No one knows how Uranus got tipped so far out of alignment with the rest of the solar system. One theory is that an encounter with another large planet twisted its spin billions of years ago. That other planet was, perhaps, flung out of the system in the encounter.

Because of its extreme tilt, Uranus also has the most extreme seasons. It is now early spring in the northern hemisphere, and gigantic storms have just been seen for the first time in the planet’s thick atmosphere. As big as continents on Earth, these huge storms are the first of a number of weather changes that will occur as Uranus enters its next long, slow season.