The planet Uranus was first discovered in 1781. It is the only planet in the Solar System that rotates at a tilt of 97.77 degrees. It is the seventh planet from the sun and has the third-largest diameter in the Solar System.
It is surrounded by 13 faint rings and is known to have 27 moons. It has also been nicknamed the "ice giant" because more than 80% of the mass of the planet is made up of a dense fluid of icy materials including water, methane, and ammonia.
Other planets in the Solar System spin vertically like tops. Uranus is the only planet that rotates on its side and scientists have always attempted to theorize why this is the case.
One of the newer theories put forth by scientists is that Uranus was hit very hard by something big so it ended up spinning sideways.
The collision would have occurred when Uranus was just a young planet, a few hundred million years old. It would have suffered a run-in with a roaming mass or ice ball.
The ball would have been massive - a few times the size of the Earth. As it collided with Uranus, the impact would have knocked off Uranus's orbit. After some time, the two masses would have merged into a single rolling world.
This theory has been tested by scientists with simulations in the lab.
Another theory is that Uranus's tilt is not due to collision but due to the migration of its moon or moons.
Of course, none of these theories can be confirmed unless scientists are able to physically visit the planet and that will not be possible anytime soon.