Astronomers at Durham University believe they may have finally cracked the mystery of Uranus’ tilted orbit and freezing temperatures.
The likely culprit appears to be a proto-planet colliding with Uranus in the infant days of the solar system.
When compared to the other eight planets, Uranus appears to be titled at an almost right angle in relation to the rest of the bodies in the system.
The planet also sports an unusually cold outer atmosphere, reaching temperatures as low -216C.
The study’s lead author Jacob Kegerreis said his team used more than 50 high-resolution computer models to determine the source of tilt.
He said: “Uranus spins on its side, with its axis pointing almost at right angles to those of all the other planets in the solar system.
“This was almost certainly caused by a giant impact, but we know very little about how this actually happened and how else such a violent event affected the planet.
“We ran more than 50 different impact scenarios using a high-powered super computer to see if we could recreate the conditions that shaped the planet’s evolution.
“Our findings confirm that the most likely outcome was that the young Uranus was involved in a cataclysmic collision with an object twice the mass of Earth, if not larger, knocking it on to its side and setting in the process the events that helped create the planet we see today.”
The proto-planet most likely grazed Uranus rather than colliding with the planet head on but the impact would have been strong enough to tilt the sphere.
The simulations also suggest the force of impact created a shell of debris around the planet’s ice layer, trapping all heat from its core.
The trapped heat could explain the extreme temperatures in Uranus’ outer atmosphere.
Scientists now think the collision could have created Uranus’ moons and rings in the aftermath.
Planetary debris launched into space after impact could have clumped together in orbit around Uranus and form its 27 known satellites and rings.
A similar theory proposes the Earth’s own moon was created when a Mars-sized body crashed into the planet in its early days.
Study co-author, Dr Luis Teodoro of the NASA Ames Research Center, said: “All the evidence points to giant impacts being frequent during planet formation, and with this kind of research we are now gaining more insight into their effect on potentially habitable exoplanets.”