Artist’s concept of a young star surrounded by a disk of gas and dust – called a protoplanetary disk. This is based on the fact that its composition is similar to that of the Sun – being made predominantly of hydrogen. In fact, it has been conjectured that it Jupiter had accumulated more mass, it would have become a second star. Jupiter acquired most of its mass from material left over from the formation of the Sun, and ended up with more than twice the combined mass of the other planets. Consistent with this theory, Jupiter is believed to have formed as a result of gravity pulling swirling clouds of gas and dust together. Our current theories regarding the formation of the Solar System claim that the planets formed about 4.5 billion years ago from a Solar Nebula (i.e. The Juno mission, which launched in August 2011 (see below), is expected to provide some insight into these questions, and thereby make progress on the problem of the core. This core may even be absent now, but a detailed analysis is needed before this can be confirmed. However, it is possible that this core has since shrunk due to convection currents of hot, liquid, metallic hydrogen mixing with the molten core. Otherwise, it would not have been able to collect all of its hydrogen and helium from the protosolar nebula – at least in theory. The presence of a core is also supported by models of planetary formation that indicate how a rocky or icy core would have been necessary at some point in the planet’s history. In 1997, the existence of the core was suggested by gravitational measurements, indicating a mass of 12 to 45 times the mass of Earth, or roughly 4%–14% of the total mass of Jupiter. The core has also been described as rocky, but this remains unknown as well. It is believed that Jupiter’s core is a dense mix of elements – a surrounding layer of liquid metallic hydrogen with some helium, and an outer layer predominantly of molecular hydrogen. The interior contains denser materials, such that the distribution is roughly 71% hydrogen, 24% helium and 5% other elements by mass. Crystals of frozen ammonia have also been observed in the outermost layer of the atmosphere. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds, as well as trace amounts of benzene and other hydrocarbons. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules, and approx. Jupiter is composed primarily of gaseous and liquid matter, with denser matter beneath. Whereas the outer layers of Jupiter are composed primarily of hydrogen and helium, increases in pressure and density suggest that closer to the core, things become solid. This is consistent with our current theories of how the Solar System and its planets formed and migrated to their current positions. And due to their intense radiation and strong gravity, any mission that attempts to study them has to do so carefully.Īnd yet, scientists have been of the opinion for decades that this massive gas giant has a solid core. Given their distance from Earth, it is time-consuming and expensive to send spacecraft to them, making survey missions few and far between. Due to their dense and swirling clouds, it is impossible to get a good look inside them and determine their true structure. The gas giants have always been a mystery to us.

Solid helium