Jupiter is renowned for being the largest planet in our solar system, making up 70% of all planetary mass. Most of this is a thick, gassy atmosphere, but it has been predicted to have a solid, rocky core. Scientists believe this core could be diminishing due to the intense atmospheric conditions near the core. A new study using updated modeling techniques has yielded evidence that the core may be dissolving much faster than previously believed, making the current state of the core unknown. Hugh Wilson of RMIT University in Melbourne, Australia, was sole author of the paper, which was published in the journal Icarus.
The atmosphere of Jupiter is roughly 90% hydrogen, 10% helium, and very little of anything else. However, the crushing pressure and extreme temperatures are so great down toward the core that the hydrogen actually exists as a supercritical fluid. The nature of this fluid would have caused some of the molecules from the core to diffuse and come away from the solid.
The exact composition of the core isn’t known, though it is predicted to have a fair amount of carbon, iron, and silicon. Wilson’s 2011 paper predicted that the rocky core contained elements that would be soluble in Jupiter’s atmosphere. He and co-author Burkhard Militzer of UC Berkeley used magnesium oxide as a probable material of the rock’s composition. In the model calculations, this proved to be quite soluble in the fluid atmosphere and indicated that Jupiter’s core is shrinking.
However, Wilson’s new research used a quantum-mechanical model to explore how certain elements believed to be abundant in Jupiter’s core would act in that fluid environment. The results suggest that this process could be occurring twice as quickly than previous research has indicated.
“Constructing accurate planetary models which include semiconvective processes requires accurate estimates of the diffusion constants of minority chemical species in planetary fluids, which have not previously been available,” Wilson wrote in the current paper.
NASA’s Juno spacecraft is currently en route to Jupiter to collect data about the planet’s composition. It is due to insert into the gas giant’s orbit on July 5, 2016. Juno is carrying a suite of instruments to analyze the planet in microwave, radio, ultraviolet, and infrared wavelengths. It will also study the gravitational particles, energetic particles, gravity, and plasma, in addition to taking close-up images. This data will give scientists a more complete picture of the conditions within Jupiter, and will be used to make more accurate models in the future about the rate at which the planet’s core is changing.
[Hat tip: New Scientist]