COMPOSITION Jupiter's composition primarily consists of hydrogen (about 75%) and helium (approximately 24%). The remaining 1% encompasses trace elements like methane, ammonia, water vapor, and other compounds. Its core likely comprises heavier elements, surrounded by layers of metallic hydrogen transitioning into liquid hydrogen. This gas giant's chemical makeup, dominated by hydrogen and helium with traces of compounds, distinguishes it as a gas-rich celestial body, differentiating it significantly from terrestrial planets in our solar system.