Jupiter Interior Graphic

A model of the interior of Jupiter is compared with that of Earth, to scale. Jupiter is mostly hydrogen, with some helium and a dusting of heavier elements. The gas giant's outer envelope is in the form of molecular hydrogen and, beneath that, the hydrogen transitions to metallic hydrogen. Most models include a layer of metallic hydrogen stabilized by exsolution of helium (aka "helium rain") at the top of the metallic hydrogen region. https://photojournal.jpl.nasa.gov/catalog/PIA25062