I recently attended a talk by a scientist working on the (FABULOUS!) Juno project, spearheaded by NASA. In light of new data from Juno, a number of these questions can be tackled for the first time.
Interestingly, Jupiters’ jet-streams run across the gas giant in bands than flow in opposite directions (antiparallel) and are asymmetric in the northern and southern hemispheres. The size, speed of flow and number of bands are related to the radius and mass of the planet. Current modelling of these parameters gives insight to the internal fluid dynamics of the gas planet, but lacking the necessary data regarding Jupiter’s interior, much speculation still remains.
Now though, close fly-bys allowed Juno to collect the necessary data near the surface of Jupiter to detect subtle differences in gravity. These differences in gravity are highly correlated with the inner workings of Jupiter. The deeper the jet-streams, the more mass they contain, the greater the gravitational field signal. They were able to correlate the gravity data with the dynamics of the weather layer and found that the weather layer goes much deeper than expected. On Jupiter (radius ~ 70,000km) the weather layer is about 3000 km deep and contains about 1% of the total mass of Jupiter, compared with Earth’s atmosphere which makes up 1 millionth of the Earth’s mass.
Another finding was that, underneath this weather layer there was a layer that rotated as a rigid body; and work is underway trying to determine the interplay between these two layers. What came first and how do they interact?
Scientists await crucial data that will be able to tackle another long-standing question regarding Jupiter: what is the nature of it’s core, if it even has one?! Current understanding suggests that Jupiter contains a diffuse core, one that does not have a well define boundary, but rather extends from the centre of the planet and is somehow mixed with other layers. However, the way things are going, and with the regular surprises that Juno is delivering, we’ll have to wait and see.
This is groundbreaking stuff! Looking forwards to hearing more from Juno and their team.
Follow Juno on Twitter