Jupiter might be having a change of heart. Literally. New simulations suggest that Jupiter's rocky core has been liquefying, melting, and mixing with the rest of the planet's innards. With this new data, astronomers hope to better explain a recent puzzling discovery of a strange planet outside of our solar system. "It's a really important piece of the puzzle of trying to figure out what's going on inside giant planets," said Jonathan Fortney, a planetary scientist at the University of California Santa Cruz who was not affiliated with the research. Conventional planetary formation theory has modeled Jupiter as a set...