Photographer Barbara Brown captured these striking aerial views in Namibia. Coastal dunes and saltworks feature in the photos from Walvis Bay, where wind, waves, evaporation, and humankind have shaped the landscape. The colorful and dendritic dune images come from Sossusvlei, where the ephemeral Tsauchab River ends in the Namib Desert. Recent flooding left its mark on the dry landscape. (Image credit: B. Brown/IAPOTY; via Colossal)
Uranus and Neptune–known as our system’s ice giants–are our least explored planets. Both have received exactly one flyby, from the Voyager 2 spacecraft. The data from those flybys remain our primary source of knowledge about each planet. The traditional model for each planet’s interior (dating back to before the flybys) consists of three layers: a rocky core; an icy mantle made up of water, ammonia, and methane; and a hydrogen/helium-rich atmosphere. That structure is one way to match the limited measurements we have from these planets, but, as today’s preprint study points out, it’s not the only way.
The authors suggest an alternative structure, in which a hydrogen-rich atmosphere overlays a supercritical magma ocean capable of dissolving hydrogen into heavier, metallic elements. Their suggestion is motivated by several factors. First, objects in the outer solar system–including Kuiper Belt objects–have less icy material than originally assumed, which suggests that Uranus and Neptune’s progenitors wouldn’t have been so ice-rich, either. Second, our understanding of how “rocky” materials respond at the temperatures and pressures found in these planet interiors has evolved. In particular, silicate, hydrogen, and iron are actually miscible at these conditions. That means that discrete sub-layers separated by material type are not as likely.
Using the magma ocean model, the team found compositions for both Uranus and Neptune that conformed well to our limited data about their gravitational and magnetic field properties. Time–and more data–will tell as to which interior model best describes these enigmatic giants. (Image credit: NASA; research credit: E. Young et al. (preprint); via Gizmodo)
For much of the year, Cañon Fiord in the Canadian Arctic lies under ice and snow, but in the summer melt season, colors peek out. Here sea ice and sediment swirl in the fjord in eddies that are kilometers wide. The sediment is largely glacial flour–rock that’s been ground into dust by glaciers. It provides critical nutrients for the marine ecosystem. (Image credit: L. Dauphin; via NASA Earth Observatory)
Iceland’s Múlajökull glacier is prone to sudden surges, where rapid ice flow is interspersed between periods of quiescence or retreat. The isolated nature of the glacier and its marshy surroundings make approaching on foot almost impossible, but photographer Dani Guindo captured gorgeous aerial images of the glacier’s many rivulets ribboning about the landscape it’s carved. (Image credit: D. Guindo; via Colossal)
Most of what we know about Earth’s interior comes from observing how seismic waves–mostly from earthquakes–bounce around. As our observations have gotten better–more seisometers, better imaging techniques–scientists have identified two large anomalies sitting near the bottom of the mantle. Known as large low-velocity provinces, or LLVPs, these zones take up continent-sized areas beneath parts of Africa and the Pacific.
The LLVPs are hot, which would normally make them buoyant, but their stationary nature suggests they are made up of extremely dense material. Narrow plumes of hot material make their way up from the LLVPs to form volcanic hotspots like those that made the Hawaiian and Galapagos Islands. Balancing that upward convection is the downward convection of former tectonic material carried into the mantle at subduction zones.
What the LLVPs are made of remains an active research question. One suggestion is that they contain remnants of Theia, the planet thought to have impacted the proto-Earth to form our Moon. (Image credits: E. Garnero and C. Richardson; see also Physics Today)
In cold weather, a new geological feature has shown up at Utah’s Great Salt Lake in the last decade. These salty mirabilite mounds form terraced crystals that resemble Yellowstone’s Mammoth Hot Springs.
Mirabilite is hydrated sodium sulfate (as opposed to the sodium chloride of table salt). The structures form when upwelling spring water partially dissolves the layer of mirabilite found beneath the lake bed. That sulfate-laden water rises to the surface, where it freezes into the crystals seen here.
When temperatures rise above freezing, the water in the mirabilite evaporates, leaving behind white, powdery thenardite. (Video credit: Great Salt Lake Institute; image credit: Utah Geological Survey)
Since 1989, Utah’s Great Salt Lake has lost some 70% of its surface area. The exposed lakebed left behind is a source of toxic dust that gets lifted into the air. Researchers are trying to understand what water sources exist beneath the lake and whether they might save the saline lake and its ecosystem from disappearing entirely.
A recent study pinpoints underground water by measuring the electrical resistance between electrodes placed meters apart in the ground (photo above). Because salty water is more electrically conductive than fresh water, the researchers can distinguish between them. So far, they’ve found quite a lot of fresh water, sometimes only a couple meters below the surface. But those patches are often quite close to saline water, too.
The group also described to Eos that they found mounds of invasive reeds lying atop concentrations of fresh water. The invasive species seems to be sucking up water that would otherwise feed back into the lake or support native plants that provide habitat to native birds. (Image credit: M. Thorne; research credit: M. Jacketta et al.; via Eos)
On 10 August 2025, the slopes of Alaska’s Tracy Arm Fjord gave way, sliding into the water. The resulting tsunami was the second-largest ever recorded, with a 481-meter runup after a 100-meter initial wave that moved at more than 70 meters per second. The fjord was fortunately empty at the time, though it is regularly visited by cruise ships. After the landslide, a seiche ricocheted through the fjord for 36 hours.
With no earthquake to trigger the tsunami, researchers had to piece together the accident through forensics. Their study concluded that the glacier’s retreat had left unstable slopes exposed, likening it to a child’s closet overstuffed with hastily gathered toys. The moment the door is no longer held closed, everything comes crashing out.
Ultimately, the landslide-induced tsunami is, therefore, a result of climate change. That result is disconcerting, given the increasing frequency of cruise ships visiting glacial fjords. Unlike earthquake-induced tsunamis, landslide-induced ones like the Tracy Arm event don’t come with a seismic warning. With rapid climate change and frequent tourism, risk management is critical. (Image credit: C. Read/USGS; research credit: D. Shugar et al.; via Eos)
Under the cold temperatures and immense pressures of a glacier, ice does not always behave in ways we’d expect. For example, cutting through ice using the pressure of a weighted wire does not break an ice block in two; as the wire passes through the ice, the melted water refreezes in its wake, leaving an intact block. Known as regelation, this process is one way that glaciers flow past obstacles in their path.
Although many experiments demonstrate regelation for ice with temperatures near freezing, the process occurs in colder ice, too. A new study combines data across a wide range of temperatures with a new physical model of regelation to show how the process changes with temperature. It seems that relatively small temperature changes drastically affect how much meltwater forms around the wire and how slowly the ice refreezes. (Image credit: S. Ferrara; video credit: SciTube; research credit: C. Meyer et al.)
People have long hoped to reliably predict volcanic eruptions. An automated system at Piton de la Fournaise in France has been doing so since 2014 with an impressive 92% accuracy. The tool, called Jerk, makes its predictions based on real-time measurements of subtle ground movements associated with magma fracturing rock on its way to the surface. Its predictions have ranged from minutes to hours before the start of an eruption.
So far, the team has only tested the system at one volcano, but they are working to install a second version at Mount Etna, where they’ll see whether other volcanoes produce a similar signal ahead of eruption. If so, Jerk could provide valuable warnings in populated areas and give geologists an automated alternative for monitoring remote volcanoes.
To learn more, check out the team’s open access paper and this interview with the team leaders over at Gizmodo. (Image credit: F. Beauducel; research credit: F. Beauducel et al.; via Gizmodo)
