The James Webb Space Telescope (JWST) has observed unprecedented and mysterious structures in Saturn's upper atmosphere: dark, bead-like features and an asymmetric, wonky star-shaped pattern. These findings, described by scientists as "completely unexpected," provide the most detailed near-infrared observations of Saturn's upper atmosphere to date.
Key Features Discovered by JWST
The fine-scaled structures were detected across two different atmospheric layers during a continuous 10-hour observation period:
Dark Beads in the Ionosphere:
Found high up in the electrically charged ionosphere, about 1,100 km (680 miles) above the cloud tops.
They appear as a series of dark, bead-like patches embedded within the bright auroral halos.
These features remained stable for hours but drifted slowly over longer periods.
Scientists speculate these beads may be caused by complex interactions between Saturn's magnetosphere and its rotating atmosphere, offering clues about the energy exchange that powers the planet's aurora.
Asymmetric Star Pattern in the Stratosphere:
Located about 500 km (310 miles) lower, in the stratosphere.
This is an asymmetric, star-shaped feature extending from the north pole toward the equator.
Intriguingly, only four of the expected six arms were visible, creating a lopsided pattern.
The arms of this star pattern appear to align with the corners of Saturn's famous hexagonal storm deeper in the atmosphere, suggesting a possible vertical connection between the deep cloud layer and the high-altitude stratosphere.
Potential Connections and Significance
The simultaneous observation of both features suggests a possible link between atmospheric layers separated by hundreds of kilometers:
Vertical Alignment: The researchers found that the darkest beads in the ionosphere appear to line up with the strongest arm of the star pattern in the stratosphere, hinting at a column of activity stretching through Saturn's atmosphere. However, it is not yet clear if this is a direct causal link or a coincidence.
Atmospheric Dynamics: These unexpected, fine-scaled patterns, rather than the expected broad bands of emissions, challenge existing models of Saturn's atmosphere and suggest previously unknown atmospheric processes are at work, possibly related to the hexagonal storm pattern.
JWST was able to make these discoveries by observing the infrared emissions from positively charged hydrogen ions () in the ionosphere and methane molecules in the stratosphere, providing valuable insights into the chemical and physical processes in Saturn's upper air.