Ancient impact may have influenced Uranus' evolution

New computer models suggest that Uranus has a tilted axis as a result of a collision with a large proto-planet 4 billion years ago.
By Joseph Scalise | Nov 09, 2018
Uranus' freezing temperatures are likely the result of a collision with a massive object twice the size of Earth, according to a new study published in The Astrophysical Journal.

In the new research, a team of international scientists set out to determine why Uranus, unlike the other planets in our solar system, is tilted on its side.

To do that, they ran a series of computer simulations that showed different large collisions between the icy world and big space objects to see if any would have affected how the planet evolved over time.

That then confirmed a past study that suggested Uranus' tilted position came about as the result of a collision with a massive object -- likely a proto-planet made of rock and ice -- some 4 billion years ago.

In addition, the research shows that debris from the impact may have formed a thin shell near the edge of the planet's ice layer and trapped in the heat coming from Uranus' core. That would then explain why Uranus has such a cold outer atmosphere.

"Uranus spins on its side, with its axis pointing almost at right angles to those of all the other planets in the solar system," said lead author Jacob Kegerreis, a research at Durham University, according"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."

This new information is important because, despite the lack of information about Uranus, it could help scientists get a better picture of how the world came to be the way that it is today.

For instance, while nobody has been sure how Uranus managed to go through such a large collision and keep its atmosphere, the models in the new study revealed that could have happened if the massive object merely glanced off the planet rather than striking it directly.

That scenario could also help explain the formation of Uranus' rings, its moons, and its off-center magnetic field.

As Uranus is similar to many known exoplanets, the team also hopes future study of the world will give them more information about galaxies beyond our own.

"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," said study co-author Luis Teodoro, a researcher at the BAER/NASA Ames Research Center, in a statement.


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