What is Jupiter made of?

Jupiter is a gas giant composed almost entirely of hydrogen and helium in various forms, with trace elements taking up only 1 percent of the planet's composition. Although it is small compared to the sun, Jupiter is over twice as heavy as all other planets in the solar system combined.

Although known as a gas giant, Jupiter is mostly made up of liquid metallic hydrogen surrounding a rock and ice core. Much remains unknown about Jupiter, but the Juno mission, which launched a probe in 2011 and is expected to arrive in 2016, may shed light on many unknown aspects of the planet.