The James Webb Space Telescope (JWST) has revealed some wonderful issues in regards to the Universe. From the earliest galaxies and planet-forming disks to characterizing exoplanet atmospheres, there’s just about no nook of the cosmos that Webb has not noticed in extraordinarily excessive decision. This consists of the Photo voltaic System, the place Webb has used its refined infrared devices and spectrometers to supply probably the most detailed photos ever taken of Jupiter, Saturn, the ice giants, and smaller objects like Dimorphos and the newest cosmic interloper detected, 3I/ATLAS.
In a recent study, a world crew of researchers introduced information from Webb’s Near Infrared Spectrograph (NIRSpec), which was obtained throughout its first observations of Saturn’s environment in 2024. These observations revealed complicated and mysterious issues which have by no means been seen on any planet within the Photo voltaic System, together with a collection of darkish, bead-like buildings and an uneven star-shaped characteristic round Saturn’s polar area.
The crew was led by Professor Tom Stallard of the Division of Maths, Physics, and Electrical Engineering at Northumbria College, Newcastle. It consisted of 23 scientists from establishments throughout the UK, the US, and France. The outcomes have been introduced on the 2025 Europlanet Science Congress Joint Meeting (EPSC-DPS2025) that happened from September seventh to twelfth in Helsinki. Their findings have been additionally detailed in a paper printed on August twenty eighth within the Geophysical Journal Letters.
Hubble picture in ultraviolet gentle exhibiting probably the most complete image of Saturn’s northern aurora. Credit score: NASA/ESA
As indicated in each, astronomers have spent the previous three many years learning thermalized emissions in Saturn’s environment brought on by the positively charged molecule hydrogen-3 (H3+). These observations, performed by ground-based and space-based telescopes, have used this molecule to discover the ionospheres of Saturn and the opposite fuel and ice giants of the outer Photo voltaic System. Nevertheless, these observations have reached a ceiling in current many years as a result of atmospheric interference and the boundaries of present devices.
This modified with the deployment of the JWST, which has basically revolutionized astronomers’ understanding of the outer planets prior to now three years.
As Professor Stallard stated in a College of Northumbria press release:
This chance to make use of JWST was the primary time now we have ever been capable of make such detailed near-infrared observations of Saturn’s aurora and higher environment. The outcomes got here as an entire shock. We anticipated seeing emissions in broad bands on the numerous ranges. As an alternative, we have seen fine-scaled patterns of beads and stars that, regardless of being separated by enormous distances in altitude, could by some means be interconnected – and may be linked to the well-known hexagon deeper in Saturn’s clouds. These options have been utterly surprising and, at current, are utterly unexplained.
The worldwide crew of researchers, comprising 23 scientists from establishments throughout the UK, US, and France, made the discoveries throughout a steady 10-hour remark interval on 29 November 2024, as Saturn rotated beneath JWST’s view. “Saturn’s higher environment has confirmed extremely troublesome to review with missions and telescope services so far as a result of extraordinarily weak emissions from this area,” stated Stallard. “JWST’s unbelievable sensitivity has revolutionised our skill to watch these atmospheric layers, revealing buildings which can be utterly not like something we have seen earlier than on any planet.”
JWST’s NIRSpec instrument allowed the crew to concurrently observe H₃⁺ ions from the ionosphere 1,100 km (683.5 mi) above Saturn’s “floor,” and methane molecules within the stratosphere beneath. Within the ionosphere, they noticed darkish, bead-like options embedded in Saturn’s polar aurorae that remained secure over hours however drifted over longer intervals. Beneath that, at an altitude of 500 km (310 mi), they noticed an uneven star-shaped characteristic (with 4 arms as a substitute of six) extending from the north pole in direction of the equator. These patterns overlaid one another at totally different ranges, with the beads mendacity on prime of the lopsided star sample.
This means that the processes driving these processes could prolong via Saturn’s environment and deep into its inside. Each options might have vital implications for understanding atmospheric dynamics on fuel big planets. Mentioned Professor Stallard:
We predict that the darkish beads could outcome from complicated interactions between Saturn’s magnetosphere and its rotating environment, probably offering new insights into the power change that drives Saturn’s aurora. The uneven star sample suggests beforehand unknown atmospheric processes working in Saturn’s stratosphere, probably linked to the hexagonal storm sample noticed deeper in Saturn’s environment. Tantalizingly, the darkest beads within the ionosphere seem to line up with the strongest star-arm within the stratosphere, nevertheless it’s not clear at this level whether or not they’re really linked or whether or not it is only a coincidence.
Whereas these options trace at mysterious processes at work, extra work is required to clarify the underlying causes. Within the close to future, the crew hopes that further time might be granted with the JWST for follow-up observations. The buildings noticed could change dramatically since Saturn is at the moment at its equinox and the northern hemisphere is about to shift into autumn. “Since neither atmospheric layer may be noticed utilizing ground-based telescopes, the necessity for JWST follow-up observations throughout this key time of seasonal change on Saturn is urgent,” Stallard added.
Additional Studying: Northumbria University, Geophysical Research Letters
