Light shines dimly through the wall of an ice cave in this photograph by Marie-Line Dentler. Shaped by melting, pressure, freezing, and fracture, these structures are dynamic and ethereal. (Image credit: M. Dentler; via Colossal)
Tag: science
Observing Ice Giant Atmospheres
Uranus is one of our solar system’s oddest inhabitants, stuck spinning on its side with a tilted and offset magnetosphere. To better understand it, a team observed the planet for 17 hours with JWST. The near-infrared measurements gave new insight into the planet’s ionosphere, where auroras form. They found that temperatures peaked between 3,000 and 4,000 kilometers, while ion densities peaked at 1,000 kilometers. They also confirmed previous observations that Uranus’s upper atmosphere is cooling down. (Image and video credit: ESA/Webb/NASA/CSA/STScI/P. Tiranti/H. Melin/M. Zamani; research credit: P. Tiranti et al.; via Gizmodo)
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Bioconvection
Convection isn’t always driven by temperature. Here, researchers explore the convective patterns formed by Thiovulum bacteria. These bacteria are negatively buoyant, meaning they will sink if they aren’t swimming. They also have an asymmetric moment of inertia, so any flow moving past them tends to affect their swimming direction.
When let loose in a Hele-Shaw cell with a oxygen levels that decrease with depth, the bacteria create complex convection-like patterns. They swim slowly upward in wide, slow plumes and sink in denser, narrow plumes. In other areas, they form large-scale rotating vortices. (Video and image credit: O. Kodio et al.)
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Turbulence and Bioluminescence
If you’ve ever seen crashing waves glowing blue, you’ve been treated to bioluminescence. Although many creatures can bioluminesce, tiny dinoflagellates–a type of marine phytoplankton–are one of the easiest to spot. These microscopic organisms create a flash of light in response to viscous stresses. Their response to flow-induced stresses is so robust that they can be used to visualize stress fields.
In a new study, researchers explored how turbulence affects the dinoflagellate’s luminescence. They mathematically modeled the dinoflagellate as an elastic dumbbell that emitted light based on its extent and rate of deformation. Then they explored how this model dinoflagellate behaved in different types of turbulent flows. They found that the fluctuations and intermittency of turbulent flows both encouraged the radiant displays. (Image credit: T. McKinnon; research credit: P. Kumar and J. Picardo)
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Colorful Tides
The colorful coastline of the Bazaruto Archipelago extends off East Africa. Regions of shallow waters, seagrass meadows, and coral reefs appear in shades of tan, green, and turquoise. Deeper waters appear blue. The coastlines, deltas, and tidal flats are shaped by moderate tides that rise and fall a few meters each day; strong currents run in the channels between islands, carving and reshaping the sediment. (Image credit: W. Liang; via NASA Earth Observatory)
“The Haboob”
Haboobs are a dust storm driven by the strong winds at the forefront of weather fronts and thunderstorms. Those powerful winds pick up dust in arid and semi-arid landscapes, creating billowing, turbulent clouds that appear downright apocalyptic.
This particular haboob formed in Arizona in August 2025 and was caught in timelapse by photographer and storm chaser Mike Olbinski. The visuals–as always–are incredible. Definitely watch to the very end, as the haboob advances on the runway at Sky Harbor Airport. The tension is palpable as you watch flights line up and try to make it off the ground before the haboob swallows them. (Video and image credit: M. Olbinski)
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Thunderstorms Make Trees Glow
Scientists have long hypothesized that the high electrical charge of thunderstorms could produce an opposite charge in the ground that would discharge from the forest canopy. But this phenomenon, known as a corona, had never been observed on actual trees. A new study, however, has observed this ghostly ultraviolet (UV) glow from the tips of sweetgum leaves and loblolly pine needles during thunderstorms.
Catching these coronae in action required a new kind of UV detector that was ultra-sensitive to the particular band of UV-light emitted by coronas, hot fires, or mercury lamps. Since the latter two weren’t present during the team’s field observations, they were able to conclude that the light they detected came from coronae.
The group observed that corona discharges were transient, jumping from leaf to leaf and branch to branch across the forest canopy. For any creature capable of detecting that glow by eye, it must be incredible to watch the treetops lit by their own ever-shifting auroras during every thunderstorm. (Image credit: W. Brune; research credit: P. McFarland et al.; via SciAm)
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Making Sound Visible
Sound is not something we can typically see, though there are ways to visualize it, including cymatics and special acoustic cameras. This video pursues a different tactic: using schlieren photography and stroboscopic lighting to show how sound waves reflect and deflect. It’s no easy feat, but one worth enjoying–especially when others have already done the hard part for you! (Video and image credit: All Things Physics; submitted by David J.)
Aging Salty Ice
When ice forms in salty water, it starts out mushy and porous. Salt does not freeze neatly into ice’s crystalline structure, so the forming ice has pores and gaps where salty brine gathers. As the ice ages, more brine is pushed out and gradually convects downward, due to its greater density. Over time, this makes the ice layer thinner but more solid, with fewer pores. You can see a timelapse of the process in a laboratory experiment below. (Image credit: sea ice – C. Matias, experiment – F. Wang et al.; research credit: F. Wang et al.)
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Mixing Bubble Caps
When bubbles form atop the ocean or in our cups, they typically live short lives. Although the bubble can exchange fluid with the pool below, this only happens at the foot of the bubble cap. There, thinner patches form and, due to their buoyancy, rise up along the bubble’s surface. Over time, these lighter, thinner patches reduce the amount of fluid in the cap–causing the bubble to thin and eventually burst.
Here, researchers show that thinning–visible in the dark blue plumes rising up the bubble cap–when there’s no turbulence in the surrounding air. But as turbulence outside the bubble increases, the thinner patches stretch and deform across the cap. In the image series, turbulence increases moving from top to bottom. (Image credit: T. Aurégan and L. Deike)
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