What is the only planet in our solar system that rotates on its side? All the planets are tilted, but none compare to Uranus. The seventh planet from the sun has a 98-degree tilt to its axis so it rotates on its side. Instead of spinning like a top around the sun the way other planets do, Uranus looks like a rolling ball.
What happened to make Uranus so different? Many astronomers suspect that billions of years ago something big crashed into Uranus and knocked it on its side.
Rotating sideways has had a big effect on the planet's seasons. Uranus orbits the sun once every 84 years. That means when its north pole points to the sun, the northern hemisphere has 42 years of sunlight. Then, it's the southern hemisphere's turn for summer and the northern side spends the next 42 years in darkness.