Jupiter has an ice/rock core the size of Uranus or Neptune, biggerthan originally thought

Jupiter's rocky core bigger and icier, model predicts
"A comparison of this model with the planet's known mass, radius,
surface temperature, gravity and equatorial bulge implies that Jupiter's
core is an Earth-like rock 14 to 18 times the mass of Earth, or about
one-twentieth of Jupiter's total mass, Militzer said. Previous models
predicted a much smaller core of only 7 Earth masses, or no core at all."
http://www.brightsurf.com/news/headl...redic ts.html