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Webb Discovers Intricate Structures in Saturn’s Upper Atmosphere

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Astronomers utilizing the NASA/ESA James Webb Space Telescope have identified a series of dark, bead-like star formations within Saturn’s ionosphere and stratosphere.

Detection of near-infrared emissions in Saturn’s ionosphere (left) reveals dark bead-like features embedded in bright auroras. In the stratosphere (right), below 500 km, an asymmetric star pattern extends toward the equator. Image credit: NASA/ESA/CSA/WEBB/STALLARD et al.

“This was the first opportunity for me to make such detailed near-infrared observations of Saturn’s aurora and upper atmosphere,” said the researcher.

“We anticipated seeing emissions across various levels.”

“Instead, we observed intricate patterns of beads and stars, which might be interconnected despite their considerable height separation and could relate to the iconic hexagon within Saturn’s clouds.”

“These features were entirely unforeseen and remain unexplained.”

The research team concentrated on detecting infrared emissions from charged molecular hydrogen, which plays a significant role in Saturn’s atmospheric dynamics, offering valuable insights into the chemical and physical processes at work.

Using Webb’s near-infrared spectrograph, scientists observed H3+ ions at an altitude of 600 km, 1,100 km above Saturn’s nominal surface, alongside lower stratospheric methane molecules.

Within the ionosphere’s electrically charged plasma, a series of dark bead-like features intermingled within bright aurora halos were detected.

These structures maintained stability for several hours but seemed to drift slowly over time.

In the stratosphere of Saturn, researchers identified asymmetric star-shaped features, dropping approximately 500 km.

This remarkable formation extended from Saturn’s North Pole down toward the equator.

Only four of the star’s six arms were visible, with two mysteriously absent, resulting in a biased pattern.

“Studying Saturn’s atmosphere has always posed challenges due to the faint emissions from that region,” remarked Professor Stallard.

“Webb’s remarkable sensitivity transforms our capacity to observe these atmospheric layers, unveiling a wholly different structural configuration than previously noted.”

The authors meticulously mapped the precise locations of features, overlaying data for the same Saturn area, discovering that the arms of the star seem to emanate from a point just above the hexagonal structure at the Stormcloud level.

This implies that the mechanisms driving the pattern could influence structures penetrating through Saturn’s atmosphere.

“We believe the dark beads arise from the intricate interactions between Saturn’s magnetosphere and its dynamic atmosphere, potentially providing new insights into the energy exchanges that fuel Saturn’s auroras,” stated Professor Stallard.

“The asymmetric star formations suggest previously unknown atmospheric processes functioning within Saturn’s stratosphere and are likely connected to the hexagonal storm pattern observed deeper in Saturn’s atmosphere.”

“Interestingly, the dark beads in the ionosphere seem to align with the arms of the strongest stars in the stratosphere, though it’s unclear whether this connection is genuine or merely coincidental.”

Both phenomena may have significant implications for our comprehension of atmospheric dynamics within the gas giant, although further investigation is needed to elucidate their underlying causes.

The team aspires for additional time to conduct follow-up observations of Saturn using Webb to explore further features.

As planets align approximately every 15 years, the structure can undergo dramatic changes as Saturn’s orientation shifts toward the Sun, moving the Northern Hemisphere into autumn.

“The necessity for follow-up Webb observations during this pivotal phase of Saturn’s seasonal transition is evident, as neither atmospheric layer can be examined using ground-based telescopes.” Paper published in the journal Geophysical Research Book.

The findings were also presented as a result this month at the EPSC-DPS2025 Joint Meeting in Helsinki, Finland.

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Tom S. Stallard et al. 2025. JWST/NIRSPEC detects the complex structures of Saturn’s ionosphere and stratosphere. Geophysical Research Book 52 (17): E2025GL116491; doi: 10.1029/2025GL116491

Tom S. Stallard et al. 2025. Transformational observations of the ionosphere of the giant planet with JWST. EPSC Abstract 18: EPSC-DPS2025-817; doi: 10.5194/epsc-dps2025-1438

Source: www.sci.news

Small Discs Can Ascend to the Upper Atmosphere Solely Using Solar Energy

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Illustration of a solar-powered levitating disc

Schafer et al. Nature

A tiny disc, roughly the size of a nail, has the potential to ascend to high altitudes in sunlight while carrying sensors through some of the coldest and thinnest parts of the atmosphere. These swarms, flying higher than commercial aircraft and balloons, could reveal new insights regarding Earth’s evolving weather and climate.

These floating devices harness a phenomenon known as photophoresis. This was initially discovered over 150 years ago when chemist William Crookes invented a radiometer, a device with black and white feathers that spin when they are exposed to sunlight. The wings absorb light and release heat, increasing the momentum of nearby gas molecules. Due to the difference in temperature between the black and white sides of the wings, the black side emits more momentum, allowing the air to flow in one direction with sufficient force to turn the wings.

“We’ve embraced this lesser-known physics to develop applications that could benefit many people, enhancing our understanding of how weather and climate change unfolds over time.” Ben Schafer from Harvard University.

To create the levitating disc, Schafer and his team designed a device that spans 1 cm, composed of two sheets of aluminum oxide filled with microscale holes. When illuminated, the lower sheet, which contains alternating layers of chromium and aluminum oxide, heats up more than the top layer, similar to the black sides of the radiometer blades. This generates a directional airflow that moves upwards instead of sideways.

Under white LED and laser illumination — set to an intensity that mimics about 50% of natural sunlight — this upward force successfully lifted the device. This represents progress over previous solar-powered flyers, which required light intensity significantly brighter than sunlight. However, the tests were conducted under laboratory conditions with air pressure much lower than Earth’s surface pressure.

Fortunately, such low pressure conditions are common at higher altitudes, especially in the Mesosphere, which spans 50-85 km above the Earth. Researchers indicate that increasing the disc’s size to 3 centimeters could enable it to carry a 10-milligram payload to hard-to-reach research areas at altitudes of 75 km. Schafer has co-founded a startup, Rare Feed Technology, aiming to commercialize fleets of these high-flying devices for environmental monitoring and communications.

After sunset, computer modeling indicates that these discs could utilize the heat radiating from Earth’s surface to remain airborne. “If they can stay afloat during the night, that represents a significant advancement instead of simply descending and landing.” Igor Bargatin from the University of Pennsylvania, who is conducting similar research.

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Source: www.newscientist.com

Human activity has profound impacts on the Earth’s upper mantle

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Ship cemetery in the desert of the Aral Sea in Uzbekistan

s@owwl / alamy

Unsustainable irrigation and drought have caused changes that have empty almost all of the waters of the Aral Sea since the 1960s, extending all the way to the Earth’s upper mantle, the layer below the Earth’s crust. This is perhaps the deepest recorded example of human activity that will change the solid inner earth.

“To do something that will affect us [upper mantle] It’s like whoa.” Sylvain Barbott At the University of Southern California. “It shows how powerful it is to change the environment.”

The Aral Sea in Central Asia was once one of the largest waters in the world, covering almost 70,000 square kilometers. However, Soviet irrigation programs that began in the 1960s and later droughts empty the oceans. By 2018, it had shrunk by almost 90% and lost about 1,000 cubic kilometres of water.

Wang Ten At Peking University in China, I was interested in the Aral Sea after reading a book about the consequences of this environmental disaster on the surface of the earth. “We’ve noticed that these huge mass changes stimulate the deep Earth’s response,” he says.

He and his colleagues, including Barbot, used satellite measurements to track subtle changes in the elevation of the oceans that were empty between 2016 and 2020. Much of the ocean water disappeared decades ago, but it was found that the uplifts were underway, with on average rising surfaces about 7 millimeters a year.

Next, we used a model of the crust and mantle beneath the Aral Sea to test the mantle beneath the Aral Sea when it came to leading to the uplift of this observed pattern. “We found that the observations were perfectly compatible with a deep response to this change,” says Barbot.

When the weight of the water was removed, the shallow crust first responded, according to the model. This prompted a response at a depth of 190 km from the surface as the viscous rocks in the upper mantle creeped up to fill the blanks. “The uncurved things create space and the rocks want to flow into it,” Barbot says. This delayed reaction in hot, weak areas of the mantle, called the athenosphere, is why the uplift is ongoing, even decades after the water is removed, he says.

The upper mantle rebound is known to occur after other major changes in surface mass, such as glacier advancement and retreat, says Roland Bürgmann At the University of California, Berkeley. But the response to drainage in the Aral Sea may be the deepest example of human-caused changes on solid earth.

Other human-induced changes, such as filling large reservoirs and pumping groundwater, are said to have also caused rebounds. Manoochehr Shirzaei At Virginia Tech. But the wider range of the Aral Sea means the impact of emptying it is likely to run deeper, he says.

In addition to explaining the enormous scale of human activity, the uplift below the Aral Sea offers an extraordinary opportunity to estimate small differences in viscosity of the mantle, particularly under the interior of the continent, Bürgmann says. “It’s really important for people trying to understand plate tectonics to know how that layer behaves under the continent.”

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Source: www.newscientist.com