Claiming to be wise, they became fools... Romans 1:22 ESV
"For generations, school posters have sorted the Solar System into tidy boxes: four small rocky planets near the Sun, two huge gas planets farther out, and, at the edge, a pair of “ice giants” – Uranus and Neptune – packed with water, ammonia, and methane.
Using a fresh kind of interior model, researchers from the University of Zurich argue that Uranus and Neptune could be far rockier than those posters suggest. In many valid solutions, the planets are just as compatible with rock-heavy interiors as with the classic ice-rich picture.
depending on the model assumptions,” said Ravit Helled, a professor from the University of Astrophysics and one of the researchers involved. “Current data are currently insufficient to distinguish the two, and we therefore need dedicated missions to Uranus and Neptune that can reveal their true nature.”
Standard diagrams show them with thick mantles of “planetary ices” — mostly water, plus ammonia and methane — sitting above a rocky core, all wrapped in a light atmosphere that contains hydrogen, helium and a bit of methane gas that gives them their blue color.
The catch is that no one has ever actually seen the insides of either planet. Voyager 2 flew past Uranus in 1986 and Neptune in 1989, measuring gravity and magnetic fields during quick flybys, then moved on. There has never been an orbiter to map their interiors in detail. So everything beneath the clouds comes from computer models that try to match a limited set of observations.
“The ice giant classification is oversimplified as Uranus and Neptune are still poorly understood,” said Luca Morf, Ph.D. student at the University of Zurich and lead author of the study. “Models based on physics were too assumption-heavy, while empirical models are too simplistic.” ZME
