Gigantic Collision Made Uranus Wonky, Astronomers Believe

by : Niamh Shackleton on : 13 Apr 2020 15:45
Gigantic Collision Made Uranus Wonky, Astronomers BelieveGigantic Collision Made Uranus Wonky, Astronomers BelieveLawrence Sromovsky, University of Wisconsin-Madison/W.W. Keck Observatory

Uranus is known for its unusual tilt, and astronomers think it was caused by a huge collision with another planet.

The planet is the only one in the solar system to orbit at a 98-degree angle and a new paper tackles the question of how it came to have this unique feature.

While previous models created by astronomers demonstrated that a huge collision was possibly the reason behind the planets tilt, the same models couldn’t recreate the distribution and composition of the moons and rings surrounding Uranus – something that has long puzzled astronomers.


However, in this new paper published in Nature Astronomy, researchers say they believe that it was a planet made largely of ice and water, which was between one and three times the mass of earth, that collided with Uranus causing the tilt.

They believe that the small icy planet is key to explaining the distribution of moons and rings around Uranus as well.

The large difference between previous models and this one is that this more recent one involves an icy planet while the others used a rocky one.


A model involving a rocky impactor suggests it would have formed denser moons around Uranus that what we currently see, IFL Science reports.

UranusUranusLawrence Sromovsky, University of Wisconsin-Madison/W.W. Keck Observatory

However, with an icy impactor, the material which was thrown into orbit following the collision mainly fell back on to Uranus – but some of it stayed in orbit. It was those pieces that remained in orbit that went on to come together to form one mass over time and therefore is thought to have created Uranus’ current configuration of moons and rings.

Part of the study reads:


Here we show, by means of a theoretical model, that the Uranian satellite formation is regulated by the evolution of the impact-generated disk. Because the vaporisation temperature of water ice is low and both Uranus and the impactor are assumed to be ice-dominated, we can conclude that the impact-generated disk has mostly vaporised.

We predict that the disk lost a substantial amount of water vapour mass and spread to the levels of the current system until the disk cooled down enough for ice condensation and accretion of icy particles to begin. From the predicted distribution of condensed ices, our N-body simulation is able to reproduce the observed mass–orbit configuration of Uranian satellites.

Crazy to think the only thing missing from their theory was ice. Where was Elsa when we needed her?

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Niamh Shackleton

Niamh Shackleton is a pint sized person and journalist at UNILAD. After studying Multimedia Journalism at the University of Salford, she did a year at Caters News Agency as a features writer in Birmingham before deciding that Manchester is (arguably) one of the best places in the world, and therefore moved back up north. She's also UNILAD's unofficial crazy animal lady.

Topics: Science, Astronomy, Collision, Solar System, Space, Uranus, Uranus tilt


IFL Science and 1 other
  1. IFL Science

    A Collision With An Ice Planet May Have Given Uranus Its Tilt And Its Moons

  2. Nature.com

    Uranian satellite formation by evolution of a water vapour disk generated by a giant impact