All the planets in the solar system are more or less oriented in the same way, with North and South pointing in the same direction. Uranus is the exception. The north-south axis of the frozen planet is inclined 98 degrees from the orbital plane of the Sun. One of the poles of the planet is permanently oriented towards the sun. It is so strange that we were clear that there was no way it could have happened by itself, and now astronomers believe they have discovered the answer.
What happened is that sometime 4 billion years ago, the planet Uranus was struck sideways by a planet roughly twice the mass of Earth. This impact was so colossal (or perhaps several small collisions) that it has been considered the most plausible reason why Uranus is orbiting around the Sun in this particular way that it has taken 84 years to travel around the Sun , first one pole of the planet is illuminated and 42 years later, the other.
Until now we knew very little about how, when and what other effects this collision had on the distant planet which is about 3 billion kilometers from the Sun.
To search for answers, the researchers have used computer simulations, placing objects of various sizes on a model of Uranus and looking at the results.
Uranus turns sideways
“We ran more than 50 different impact scenarios using a high-powered supercomputer to see if we could recreate the conditions that shaped the evolution of the planet,” said lead physicist Jacob Kegerreis of the University of Durham (UK). . “Our findings confirm that the most likely outcome was that young Uranus was involved in a catastrophic collision with an object twice the mass of Earth.”
The event likely occurred about 4 billion years ago, during the early stages of the solar system. And such a cataclysm can clearly explain other unusual aspects about Uranus.
How did it manage to maintain its atmosphere when what should be expected from a violent collision is to send it into space?
According to the simulations, this can be explained by the impact of the object hitting the planet. The collision was strong enough to affect Uranus’ tilt, but the planet was able to retain most of its atmosphere.
The impact was able to throw rocks and ice into orbit around the planet. These materials could have clumped together to form the planet’s inner satellites and perhaps altered the rotation of pre-existing moons already orbiting Uranus.
The simulations show that the impact could have created molten ice and sloping blocks of rock within the planet. This could help explain Uranus’ lopsided and off-center magnetic field.
The model presented certainly seems to answer all the doubts about the planet, which is amazing, because learning more about Uranus and how it came to be so strange can help to understand the evolution of other planets of the same nature that exist in the universe. Uranus is similar to the most common type of planets that we can find outside of our solar system.
Reference: Consequences of Giant Impacts on Early Uranus for Rotation, Internal Structure, Debris, and Atmospheric Erosion. Astrophysical Journal (July 2018). DOI: 10.3847 / 1538-4357 / aac725
