Something unexpected is going on in Saturn’s upper atmosphere – and scientists don’t know what it is yet. The planet has always been a mystery, with its iconic rings and that strange six-sided storm near the north pole known as the hexagon.
But now, using NASA’s James Webb Space Telescope (JWST), astronomers have spotted strange patterns in Saturn’s upper atmosphere that have never been seen before – on any planet.
The experts were hoping for clearer views of the usual features, such as emissions from hydrogen molecules.
What they got instead? Beads of darkness in glowing auroras, a lopsided star shape stretching through the sky, and hints that all these layers of Saturn’s atmosphere might somehow be talking to each other.
Auroras and stars intertwine above
On November 29, 2024, researchers spent 10 hours tracking Saturn with JWST as the planet spun beneath the telescope’s powerful gaze.
The team focused on two things: protonated molecular hydrogen ions (H₃⁺) and methane. These molecules light up under infrared wavelengths and tell scientists what’s happening at different heights above Saturn’s cloud tops.
JWST’s Near Infrared Spectrograph looked at two main layers. One was Saturn’s ionosphere – about 680 miles above the planet’s surface. The other was the stratosphere – about 370 miles up.
In the ionosphere, the experts found “a series of dark, bead-like features embedded in bright auroral halos.” These beads didn’t flash or flicker.
They stayed stable for hours, only drifting slowly over time. That’s not normal. Planetary auroras usually shift and change quickly.
About 310 miles lower, in the stratosphere, they found something even stranger: a star-shaped pattern with four visible arms stretching out from Saturn’s north pole toward the equator. Two arms were missing, making the whole thing look off-balance.
These patterns lined up vertically, like stacked layers above the same parts of the planet. And strangely, the brightest part of the star-shaped pattern matched the position of the darkest bead above it.
Saturn’s hexagon tied to auroras
Down deep in Saturn’s cloud tops is a massive, six-sided storm. It’s been there since at least the 1980s, and it’s still spinning. Scientists don’t fully understand it, but they’ve studied it with missions like Cassini.
The new JWST data seems to show that the upper layers of Saturn’s atmosphere might be linked to this hexagon far below. The star’s arms appear to come from right above the hexagon’s corners.
This could mean that some process is pulling or pushing energy straight up through Saturn’s layers – from the stormy clouds to the glowing ionosphere.
“Saturn’s upper atmosphere has proven incredibly difficult to study with missions and telescope facilities to date due to the extremely weak emissions from this region,” said Professor Tom Stallard of Northumbria University, who presented the findings at a science meeting in Helsinki.
“JWST’s incredible sensitivity has revolutionized our ability to observe these atmospheric layers, revealing structures that are completely unlike anything we’ve seen before on any planet.”
Energy flows through Saturn’s skies
H₃⁺ isn’t just another molecule. It plays a big role in the way energy flows through Saturn’s atmosphere. It’s also tied to the planet’s magnetosphere – its huge, invisible magnetic bubble.
“The dark beads may result from complex interactions between Saturn’s magnetosphere and its rotating atmosphere, potentially providing new insights into the energy exchange that drives Saturn’s aurora,” said Stallard.
“The asymmetric star pattern suggests previously unknown atmospheric processes operating in Saturn’s stratosphere, possibly linked to the hexagonal storm pattern observed deeper in Saturn’s atmosphere.”
This might be the first real clue that Saturn’s layers – from deep clouds to high-energy plasma – are more connected than anyone thought. But right now, the details are still murky.
“Tantalizingly, the darkest beads in the ionosphere appear to line up with the strongest star-arm in the stratosphere, but it’s not clear at this point whether they are actually linked or whether it’s just a coincidence,” said Stallard.
Catching Saturn’s changes in time
It’s not easy to study Saturn’s upper atmosphere. From Earth, we just can’t see it. JWST changed that. But time with this space telescope is limited and highly competitive.
“Since neither atmospheric layer can be observed using ground-based telescopes, the need for JWST follow-up observations during this key time of seasonal change on Saturn is pressing,” said Stallard.
And timing matters. Right now, Saturn is at equinox – when day and night are equal in length. This happens about every 15 Earth years.
The way sunlight hits the planet is changing. As the northern hemisphere heads into autumn, those strange features might change – or disappear entirely.
The team hopes to catch those changes before they’re gone. That could be the key to figuring out what these weird patterns really are, and how deep Saturn’s secrets run.
The full study was published in the journal Geophysical Research Letters.
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