Scientists at Universidade of Zurique (UZH) and NCCR PlanetS at Suíça have published research that questions the traditional classification of Urano and Netuno as ice giants. The work, published this Wednesday (11) in the magazine Astronomy & Astrophysics, indicates that the two planets may have predominantly rocky interiors.
The team developed a hybrid method that combines fundamental physical models with observational data. The results show that rock-rich compositions are as plausible as those based on water ice.
New simulation method changes planetary understanding
The researchers generated thousands of random density profiles for the interiors of planets. Cada profile was tested against known gravity data, obtained mainly by the Voyager 2 mission in 1986 and 1989.
The process respected physical laws such as hydrostatic equilibrium, energy conservation and thermodynamic behavior of materials. The approach made it possible to identify compatible internal compositions without previously imposing ice dominance.
Rock composition explains anomalous magnetic fields
Uranus and Netuno have misaligned and multipolar magnetic fields, different from the dipolar fields of Júpiter and Saturno. The new model suggests that a rockier, less conductive interior could generate magnetic dynamos in deeper layers.
The research indicates that the magnetic field of Urano would be generated in an even deeper region than that of Netuno. Essa difference would help explain why Urano has a magnetic tilt of almost 60 degrees.
Differences between the two planets gain new interpretation
- Uranus has an extreme lateral rotation of 98 degrees
- Neptune emits more internal heat than Urano barely emits
- Uranus has a more complex and displaced magnetic field
- Neptune shows greater visible atmospheric activity
These characteristics, previously attributed solely to the presence of ice, can be explained by variations in the rock-ice proportion and the distribution of materials.
Uncertainties remain due to extreme conditions
Scientists recognize that the behavior of materials under pressures of millions of atmospheres and temperatures of thousands of degrees is still little known. Experimentos in laboratory and advanced computer simulations remain limited under these conditions.
The team highlights that both ice-rich and rock-rich scenarios fit the current data. The definitive distinction will depend on more precise measurements.
Future missions are considered essential
Experts say that only a dedicated probe will be able to resolve the issue. Instrumentos modern systems could accurately map the gravitational and magnetic field during flybys or orbital entry.
NASA and ESA are currently studying mission proposals for the 2030-2040 decade. Urano is a priority in the latest American Decadal Survey, while Netuno also receives increasing attention.
Hybrid model paves the way for studying exoplanets
The methodology developed in Suíça does not require prior assumptions about composition. Esse aspect makes the method applicable to extrasolar planets where only mass and radius are known.
The work demonstrates that simple classifications such as “ice giant” may not capture only part of the reality. Planetas with similar characteristics to Urano and Netuno are common in the galaxy, making refinement of the models crucial for exoplanetology.
The research reinforces that Urano and Netuno represent a distinct planetary class, possibly more diverse than previously thought. Fully understanding these worlds requires a continuous combination of observations, experiments and advanced computer simulations.