Jupiter has a mysterious internal heat source which is not based on nuclear fission.
The core of the planet is extremely hot but not enough for nuclear fusion either. The heat source cannot be leftover from planetary formation as it is far too intense. There are many conjectures about the source of heat since all the usual suspects can be ruled out. It is therefore possible if not likely that ultradense hydrogen in somehow involved. Well, I suppose that is why you posted it <g>. From: Axil Axil http://science.sciencemag.org/content/361/6403/677 Insulator-metal transition in dense fluid deuterium Abstract Dense fluid metallic hydrogen occupies the interiors of Jupiter, Saturn, and many extrasolar planets, where pressures reach millions of atmospheres. Planetary structure models must describe accurately the transition from the outer molecular envelopes to the interior metallic regions. We report optical measurements of dynamically compressed fluid deuterium to 600 gigapascals (GPa) that reveal an increasing refractive index, the onset of absorption of visible light near 150 GPa, and a transition to metal-like reflectivity (exceeding 30%) near 200 GPa, all at temperatures below 2000 kelvin. Our measurements and analysis address existing discrepancies between static and dynamic experiments for the insulator-metal transition in dense fluid hydrogen isotopes. They also provide new benchmarks for the theoretical calculations used to construct planetary models. The article is questioned here http://science.sciencemag.org/content/363/6433/eaaw0969 The transition pressure to melalize deutriem is lower that expected from first principle calculations. That meltaliation transition pressure is measured to occur at 2,000,000 Bar. For comment on the critique see http://science.sciencemag.org/content/363/6433/eaaw1970
