Building a Better Fog Harp

On arid coastlines, fog rolling in can serve as an important water source. Today’s fog collectors often use tight mesh nets. The narrow holes help catch tiny water particles, but they also clog easily. A few years ago, researchers suggested an alternative design — a fog harp inspired by coastal redwoods — that used closely spaced vertical wires to capture water vapor. At small scales, this technique worked well, but once scaled up to a meter-long fog harp, the strings would stick together once wet — much the way wet hairs cling to one another.

The group has iterated on their design with a new hybrid that maintains the fog harp’s close vertical spacing but adds occasional cross-wires to stabilize. Laboratory tests are promising, with the new hybrid fog harp collecting water with 2 – 8 times the efficiency of either a conventional mesh or their original fog harp. The team notes that even higher efficiencies are possible with electrification. (Image credit: A. Parrish; research credit: J. Kaindu et al.; via Ars Technica)

"We discovered that the flickering snake tongue generates two pairs of small, swirling masses of air, or vortices, that act like tiny fans, pulling odors in from each side and jetting them directly into the path of each tongue tip."

https://theconversation.com/smelling-in-stereo-the-real-reason-snakes-have-flicking-forked-tongues-142363

Martian Streaks Are Dry

Dark lines appearing on Martian slopes have triggered theories of flowing water or brine on the planet’s surface. But a new study suggests that these features are, instead, dry. To explore these streaks, the team assembled a global database of sightings and correlated their map with other known quantities, like temperature, wind speed, and rock slides. By connecting the data across thousands of streaks, they could build statistics about what variables correlated with the streaks’ appearance.

What they found was that streaks didn’t appear in places connected to liquid water or even frost. Instead, the streaks appeared in spots with high wind speeds and heavy dust accumulation. The team included that, rather than being moist areas, the streaks are dry and form when dust slides down the slope, perhaps triggered by high winds or passing dust devils.

Although showing that the streaks aren’t associated with water may seem disappointing, it may mean that NASA will be able to explore them sooner. Right now, NASA avoids sending rovers anywhere near water, out of concern that Earth microbes still on the rover could contaminate the Martian environment. (Image credit: NASA; research credit: V. Bickel and A. Valantinas; via Gizmodo)

Listening for Pollinators

Can plants recognize the sound of their pollinators? That’s the question behind this recently presented acoustic research. As bees and other pollinators hover, land, and take-off, their bodies buzz in distinctive ways. Researchers recorded these subtle sounds from a Rhodanthidium sticticum bee and played them back to snapdragons, which rely on that insect. They found that the snapdragons responded with an increase in sugar and nectar volume; the plants even altered their gene expression governing sugar transport and nectar production. The researchers suspect that the plants evolved this strategy to attract their most efficient pollinators and thereby increase their own reproductive success. (Image credit: E. Wilcox; research credit: F. Barbero et al.; via PopSci)

Rolling Down Soft Surfaces

Place a rigid ball on a hard vertical surface, and it will free fall. Stick a liquid drop there, and it will slide down. But researchers discovered that with a soft sphere and a soft surface, it’s possible to roll down a vertical wall. The effect requires just the right level of squishiness for both the wall and sphere, but when conditions are right, the 1-millimeter radius sphere rolls (with a little slipping) down the wall.

Rolling requires torque, something that’s usually lacking on a vertical surface. But the team found that their soft spheres got the torque needed to roll from their asymmetric contact with the surface. More of the sphere contacted above its centerline than below it. The researchers compared the way the sphere contacted the surface to a crack opening (at the back of the sphere) and a crack closing (at the front of the sphere). That asymmetry creates just enough torque to roll the sphere slowly. The team hopes their discovery opens up new possibilities for soft robots to climb and descend vertical surfaces. (Image and research credit: S. Mitra et al.; via Gizmodo)

Imagine being a brilliant physicist/mathematician and still avoiding the most important problems because your career depends on publishing frequent papers, not solving the biggest mysteries in the world.

That's why you can't do things like this in academia.

https://english.elpais.com/science-tech/2025-06-24/spanish-mathematician-javier-gomez-serrano-and-google-deepmind-team-up-to-solve-the-navier-stokes-million-dollar-problem.html

Seeing the Sun’s South Pole For the First Time

The ESA-led Solar Orbiter recently used a Venus flyby to lift itself out of the ecliptic — the equatorial plane of the Sun where Earth sits. This maneuver offers us the first-ever glimpse of the Sun’s south pole, a region that’s not visible from the ecliptic plane. A close-up view of plasma rising off the pole is shown above, and the video below has even more.

Solar Orbiter will get even better views of the Sun’s poles in the coming months, perfect for watching what goes on as the Sun’s 11-year-solar-cycle approaches its maximum. During this time, the Sun’s magnetic poles will flip their polarity; already Solar Orbiter’s instruments show that the south pole contains pockets of both positive and negative magnetic polarity — a messy state that’s likely a precursor to the big flip. (Image and video credit: ESA & NASA/Solar Orbiter/EUI Team, D. Berghmans (ROB) & ESA/Royal Observatory of Belgium; via Gizmodo)

https://www.youtube.com/watch?v=TU4DcDgaMM0

“Now I See – The Collection Vol. 2”

In the next video of his current collection, Roman De Giuli takes us flying over liquid landscapes that look like our Earth in miniature. Many of them have the feeling of river deltas or glaciers. Sharp-eyed viewers will notice bubbles and flotsam in some of these streams. If you follow them, you can see how the flows vary — wiggling around islands, speeding up through constrictions and slowing down when the stream widens. It is, as always, a beautiful form of flow visualization. (Video and image credit: R. De Giuli)

Predicting Yield

We’ve all experienced the frustration of ketchup refusing to leave the bottle or toothpaste that shoots out suddenly. These materials are yield stress fluids, which transition from solid-like behavior to liquid flow once the right amount of force is applied. A new study suggests that — despite their wide range of characteristics — these fluids share a universal relation: their yield transition (when they start to flow) depends on their characteristics when at rest. Interestingly, this relationship seems to hold not only for polymeric fluids like the one in the study but also nonpolymeric ones. (Image credit: haideyy; research credit: D. Keane et al.; via APS Physics)

Evaporating Off Butterfly Scales

This award-winning macro video shows scattered water droplets evaporating off a butterfly‘s wing. At first glance, it’s hard to see any motion outside of the camera’s sweep, but if you focus on one drop at a time, you’ll see them shrinking. For most of their lifetime, these tiny drops are nearly spherical; that’s due to the hydrophobic, water-shedding nature of the wing. But as the drops get smaller and less spherical, you may notice how the drop distorts the scales it adheres to. Wherever the drop touches, the wing scales are pulled up, and, when the drop is gone, the scales settle back down. This is a subtle but neat demonstration of the water’s adhesive power. (Video and image credit: J. McClellan; via Nikon Small World in Motion)

Io’s Missing Magma Ocean

In the late 1970s, scientists conjectured that Io was likely a volcanic world, heated by tidal forces from Jupiter that squeeze it along its elliptical orbit. Only months later, images from Voyager 1’s flyby confirmed the moon’s volcanism. Magnetometer data from Galileo’s later flyby suggested that tidal heating had created a shallow magma ocean that powered the moon’s volcanic activity. But newly analyzed data from Juno’s flyby shows that Io doesn’t have a magma ocean after all.

The new flyby used radio transmission data to measure any little wobbles that Io caused by tugging Juno off its expected course. The team expected a magma ocean to cause plenty of distortions for the spacecraft, but the effect was much slighter than expected. Their conclusion? Io has no magma ocean lurking under its crust. The results don’t preclude a deeper magma ocean, but at what point do you distinguish a magma ocean from a body’s liquid core?

Instead, scientists are now exploring the possibility that Io’s magma shoots up from much smaller pockets of magma rather than one enormous, shared source. (Image credit: NASA/JPL/USGS; research credit: R. Park et al.; see also Quanta)

“Droplet on a Plucked Wire”

What happens to a droplet hanging on a wire when the wire gets plucked? That’s the fundamental question behind this video, which shows the effects of wire speed, viscosity, and viscoelasticity on a drop’s detachment. With lovely high-speed video and close-up views, you get to appreciate even subtle differences between each drop. Capillary waves, viscoelastic waves, and Plateau-Rayleigh instabilities abound! (Video and image credit: D. Maity et al.)

“C R Y S T A L S”

In “C R Y S T A L S,” filmmaker Thomas Blanchard captures the slow, inexorable growth of potassium phosphate crystals. He took over 150,000 images — one per minute — to document the way crystals formed as the originally transparent liquid evaporated. Some crystals branch into fractals. Others bulge outward like a condensing cloud or a sprouting mushroom. (Video and image credit: T. Blanchard)

17-Jun-2025
Sculpting the surface of the #water
Researchers at the University of Liège are revolutionising the handling of #liquids and floating objects thanks to #capillary action.
https://www.eurekalert.org/news-releases/1087817 #science #fluidDynamics #physics

Stunning Interstellar Turbulence

The space between stars, known as the interstellar medium, may be sparse, but it is far from empty. Gas, dust, and plasma in this region forms compressible magnetized turbulence, with some pockets moving supersonically and others moving slower than sound. The flows here influence how stars form, how cosmic rays spread, and where metals and other planetary building blocks wind up. To better understand the physics of this region, researchers built a numerical simulation with over 1,000 billion grid points, creating an unprecedentedly detailed picture of this turbulence.

The images above are two-dimensional slices from the full 3D simulation. The upper image shows the current density while the lower one shows mass density. On the right side of the images, magnetic field lines are superimposed in white. The results are gorgeous. Can you imagine a fly-through video? (Image and research credit: J. Beattie et al.; via Gizmodo)

Summer + pools = a real physics experiment

Scientists studied what causes the biggest splash in the water — from air resistance to surface tension.

It’s all fluid dynamics.
And it’s a great reminder that physics explains everything around us.

Read the full breakdown here:
https://www.sciencenews.org/article/biggest-splash-pool-manu-science

Ponding on the Ice Shelf

Glaciers flow together and march out to sea along the Amery Ice Shelf in this satellite image of Antarctica. Three glaciers — flowing from the top, left, and bottom of the image — meet just to the right of center and pass from the continental bedrock onto the ice-covered ocean. The ice shelf is recognizable by its plethora of meltwater ponds, which appear as bright blue areas. Each austral summer, meltwater gathers in low-lying regions on the ice, potentially destabilizing the ice shelf through fracture and drainage. This region near the ice shelf’s grounding line is particularly prone to ponding. Regions further afield (right, beyond the image) are colder and drier, often allowing meltwater to refreeze. (Image credit: W. Liang; via NASA Earth Observatory)

Penguin Poo Seeds Antarctic Clouds

Forming clouds requires more than just water vapor; every droplet in a cloud forms around a tiny aerosol particle that serves as a seed that vapor can condense onto. Without these aerosols, there are no clouds. In most regions of the world, aerosols are plentiful — produced by vegetation, dust, sea salt, and other sources. But in the Antarctic, aerosol sources are few. But a new study shows that penguins help create aerosols with their feces.

Penguin feces is ammonia-rich, and that ammonia, when combined with sulfur compounds from marine phytoplankton, triggers chemistry that releases new aerosol particles. The researchers measured ammonia carried on the wind from nearby penguin colonies and found that the birds are a large ammonia source, producing 100 to 1000 times the region’s baseline ammonia levels. In combination with another ingredient in penguin guano, the researchers found the penguins boosted aerosol production 10,000-fold. That means penguins can actually influence their environment, helping to create clouds that keep Antarctica cooler. (Image credit: H. Neufeld; research credit: M. Boyer et al.; via Eos)

Proving Superdiffusion

Turbulence is very good at spreading things out. Drop dye into a turbulent flow and it will quickly disperse. Add in particles — like rubber ducks — and they can spread apart, often at speeds quicker than one would expect, based on the background flow. This is (roughly speaking) a phenomenon known as “superdiffusion,” where turbulence makes particles that start out as neighbors part ways.

Physicists conjectured that turbulence — including simplified and idealized versions of it that are simpler to deal with — had this superdiffusion property, but no one was able to show that in a mathematically rigorous way. But now a group of mathematicians has done so, using a technique known as homogenization. There’s a lot more on the story over at Quanta, or you can check out the original papers on arXiv. (Image credit: J. Richard; research credit: S. Armstrong et al. and S. Armstrong and T. Kuusi; see also Quanta)

Artificial Reoxygenation

Phytoplankton blooms have blossomed in coastal waters around the world, driven by phosphorus and nitrogen in agricultural run-off. These large algal blooms deplete oxygen in the water, creating dead zones where fish and other marine life cannot survive. Typically, oxygen makes its way into the ocean at the surface, where breaking waves trap air in bubbles that, when tiny enough, dissolve their oxygen into the water. But this process mainly helps surface-level waters, and without means to circulate oxygen-rich water down to the depths, the low-oxygen state persists.

Artificial reoxygenation is a possible countermeasure. Either by bubbling oxygen directly into deeper waters or by pumping surface-level water downward, we could increase oxygen levels in the water column. So far, though, artificial reoxygenation’s success has been limited; tests in a few bays and estuaries show that it’s possible to reoxygenate the water, but the effects only last as long as the artificial mechanism remains active. Stop the pumps and bubblers and the water will revert to its low-oxygen state in just a day. Even so, the measures may be worthwhile on a temporary basis in some places while we adjust agricultural practices and try to mitigate warming. (Image credit: Copernicus Sentinel/ESA; via Eos)