Jakarta –
So far, Uranus and Neptune are known as the ice giants in the Solar System. However, recent research from the University of Zurich and NCCR PlanetS challenges this assumption.
Based on new simulation results, the two blue planets are likely rockier rather than icy, a departure from traditional classifications.
According to the University of Zurich (UZH) page, a team of scientists discovered that the composition of Uranus and Neptune is not solely dominated by ice like water, but could be more like solid rock. This finding opens up the possibility that the two planets need to be recategorized, namely not just ‘ice giants’, but ‘rock giants’.
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New Simulation Reveals the Rocky Side of Uranus and Neptune
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Uranus could be an ice giant (left) or a rock giant (right) depending on the model assumptions used, the researchers said. Photo: Keck Institute for Space Studies/Chuck Carter
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In this research, the UZH team developed a new simulation process to model the interiors of both planets. So far, the physical models used are considered to be too dependent on assumptions, while the empirical models are too simple.
“The classification of ice giants is oversimplified because Uranus and Neptune are still very poorly understood,” explained Luca Morf, a doctoral student at the University of Zurich and lead author of the study.
“So far, physics-based models have too many assumptions, while empirical models are too simple. We combined the two to create an interior model that is scientifically neutral, but remains physically consistent,” added Morf.
Using that approach, the team started with a random density profile for the planet’s interior, then calculated a gravitational field that was consistent with the observational data. This process is repeated many times until the results that best match the model and actual data are obtained.
Professor Ravit Helled, a senior scientist at the University of Zurich who led the project, explained that the simulation results show that the composition of Uranus and Neptune is likely to be much more varied.
“This is something we first proposed about 15 years ago, and now we have a numerical framework to prove it,” he said.
The results show that the two planets could be rich in water or rich in rock, depending on the model assumptions used.
Have More Than Two Poles?
This discovery also helps explain the nature of the complex magnetic fields that Uranus and Neptune have. Unlike Earth which has two clear magnetic poles, the magnetic fields of the two planets have more than two poles.
“Our model has layers of ionic water that generate magnetic dynamos at locations that explain the observed nondipolar magnetic fields. We also found that Uranus’s magnetic field originates from deeper layers than Neptune’s,” Helled said.
However, the researchers admit there is still great uncertainty. According to Morf, physicists do not yet fully understand how materials react under extreme conditions of pressure and temperature in planetary cores.
“One of the main problems is that physicists still barely understand how materials behave under the unique pressure and temperature conditions found in the heart of the planet, this can affect our research results,” he said.
Need a New Space Mission
However, this research opens up a new perspective on the structure of large planets in the Solar System.
“Uranus and Neptune could be ice giants or rock giants, depending on the model assumptions. The current data is not enough to distinguish between the two. Therefore, we need special missions to Uranus and Neptune to reveal their true nature,” emphasized Helled.
(rhr/twu)
