A team of astronomers have used the James Webb Space Telescope to take a closer look at Jupiter's upper atmosphere, and have discovered some surprising structures.
The region observed in the study using the Webb Telescope is located right above the Great Red Spot.
This section of Jupiter's atmosphere was originally thought to be unremarkable, homogenous even, but in fact displays a variety of structures and activity.
Jupiter upper atmosphere explained
Jupiter's upper atmosphere is the section between its magnetic field and underlying atmosphere.
It's within Jupiter's upper atmosphere that its aurorae can be seen.
And while ground-based telescopes struggle to observe much in Jupiter's upper atmosphere other than the aurorae at the gas giant's north and south poles, the Webb Telescope's infrared vision gives astronomers a much clearer picture.
At Jupiter's poles, aurorae are fuelled by volcanic material from Jupiter's moon Io, the most volcanic body in the Solar System.
Closer to the equator, where the Great Red Spot lies, the structure of the upper atmosphere is affected by sunlight.
And because Jupiter receives 4% of the sunlight that Earth receives, astronomers had expected this region to be homogenous and relatively unremarkable.
Webb's exploration of Jupiter's upper atmosphere
The Great Red Spot was observed by Webb's NIRSpec instrument in July 2022, and the team of astronomers behind the study were investigating to see whether the region above it, in the upper atmosphere, was as unremarkable as they had expected.
Yet the team discovered a variety of intricate structures like dark arcs and bright spots.
"We thought this region, perhaps naively, would be really boring," says team leader Henrik Melin of the University of Leicester in the United Kingdom.
"It is in fact just as interesting as the northern lights, if not more so. Jupiter never ceases to surprise."
So if the light emitted from this region is driven by sunlight, does that mean it's sunlight that's causing these strange formations to appear?
Not so, says the team, arguing that there must be some other mechanism at play.
"One way in which you can change this structure is by gravity waves - similar to waves crashing on a beach, creating ripples in the sand," says Melin.
"These waves are generated deep in the turbulent lower atmosphere, all around the Great Red Spot, and they can travel up in altitude, changing the structure and emissions of the upper atmosphere."
What next?
Now the team intends to carry out follow-up Webb observations of the intricate wave patterns above the Great Red Spot, to examine how the patterns move within the planet’s upper atmosphere.
Future studies could help our understanding of how these features change over time.
Read the full paper at www.nature.com/articles/s41550-024-02305-9
