As it turns out, Uranus has more history than just being gassy, it has taken a really really hard pounding, at least two times. These impacts have actually caused the planet to be tilted completely sideways. Think about it like a spinning top, instead of Uranus spinning around the sun, it’s actually rolling like a giant ball.
Uranus’ axis is tilted at almost 98 degrees, this means that if you lived in the planet, you would have a life time either full of sun, or full of darkness. One of the poles is pointing directly at the sun getting over 42 years of sunlight followed by 42 years of darkness. There would be a couple of years in the middle where the planet appears to be normal.
Because every other planet in our system spins “normal” and Uranus is the only one that “rolls” sideways, scientist have always tried to figure out why this is. Astronomers at Cote d’Azur in Nice France believe they have an answer. They ran several simulations that shows that Uranus suffered from two giant impacts.
They believe that the only way to change the spinning axis of a planet is to smash it with another planet the same size. Planets now days hardly ever crash against one another, but this was something that was happening on the regular basis back in the early ages of our universe. A planet the size of mars could have impacted earth over 4 billion years ago and it probably blasted off enough debris to form the moon. But a planet the size of Uranus crashing against another planet the same size would have more effects than just knocking the planet sideways, it would of destroyed Uranus’ moons, which we all know it couldn’t of happened.
They replaced the one giant impact with two smaller impacts, and it worked out perfectly. Each one of the impacts would have involved a fairly big planet, something the size of the earth, punching Uranus several billion years ago effectively tilting it’s axis and allowing the moons to have their current formation.