A team from the University of Zurich, led by PhD student Luca Morf and initiated by professor Ravit Helled, developed a new simulation process for planetary interiors. They argue that the "ice giant" classification for Uranus and Neptune is oversimplified because previous models were either too assumption-heavy or too simple.
The method starts with a random density profile for the planet's interior. The researchers compute the gravitational field that matches observational data and infer a possible composition. They repeat this cycle many times to find models that best match observations. Using this approach, they found the internal composition need not be dominated by ice (usually represented by water); the planets could be either water-rich or rock-rich.
The models also offer an explanation for the unusual magnetic fields of Uranus and Neptune. They include so-called "ionic water" layers that can generate magnetic dynamos in locations that produce non-dipolar fields. The study notes that Uranus' magnetic field appears to originate deeper than Neptune's. The research appears in Astronomy & Astrophysics and is from the University of Zurich.
Difficult words
- simulation — computer model of a real process
- interior — inside part of a planet or objectinteriors
- density profile — how material density changes inside something
- gravitational field — force field around a mass that attracts
- composition — what a planet or object is made of
- ionic water — water with charged particles or ions
- magnetic field — area where magnetic forces act around objectmagnetic fields
- oversimplified — described too simply, missing important details
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Discussion questions
- Do you think the term "ice giant" is still useful for Uranus and Neptune? Why or why not?
- If a planet is rock-rich rather than water-rich, how could that change scientists' study methods? Give one or two reasons.
- Why are unusual magnetic fields interesting for researchers and space missions?
