Why does Uranus spin on its side?
The Sideways Planet
Why does Uranus spin on its side?
Most planets spin like spinning tops, twirling neatly upright as they loop around the Sun. Then there's Uranus, the oddball of the family, lying on its side like a marble rolling across a table. It's not posing for a photo. It genuinely got knocked over — and the story of how is one of the best mysteries in the solar system.
First, what does "spinning on its side" even mean? Think of a planet's spin axis as an invisible skewer poked through its top and bottom. Most planets keep that skewer pointing mostly up-and-down as they orbit. Uranus's skewer points almost sideways — about 98 degrees over. It basically rolls around the Sun instead of standing on it.
