How does Uranus manage to spin on its side?

Uranus is the Solar System’s most tilted major planet, with its axis nearly lying in the plane of its orbit. The most widely accepted explanation is that it was struck by one or more giant bodies during the chaotic early Solar System. That impact may have knocked the planet onto its side, giving it unusual seasons and making its poles alternate between long periods of sunlight and darkness. Voyager 2’s 1986 flyby provided the first close-up look at this strange world. Uranus’s sideways orientation makes it one of the most distinctive planets in the Solar System.