In early February 2026, cold weather swept into southern Florida. The cold fronts churned up sediment and cooled shallow waters, making them denser than the warmer waters of the open ocean. That caused the cooled water to sink off the continental shelf, carrying bright sediment with it. The satellite images of swirling sediment remind me of Impressionist paintings. (Image credit: M. Garrison; via NASA Earth Observatory)
Breaking a jet of liquid into droplets lies at the heart of many industrial processes: spray painting, fuel injection, and asthma inhalers, to name a few. Here, researchers are looking at a different method of breaking up a liquid jet: shooting a shock wave along its length. The poster shows five different snapshots of the jet’s response. There are, variously, mists of fine droplets, wavy distortions of the jet, sheets, ligaments, and droplets of many sizes. (Image credit: S. Rao et al.)
Insect flight is vastly different than the aerodynamics engineers learn around aircraft. That’s particularly apparent looking at these tiny moths taking off and flying in slow motion. Almost every feature seems, at first glance, aerodynamically wasteful. Hairy, scaly surfaces instead of smooth ones? Relatively small wings for their body size? Moths break our engineering intuition.
For moths, flight is an inherently unsteady process. Every stroke of its wings cups and flings fluid away in an effort to generate enough lift to stay aloft. Notice how the wings flex with each stroke. Part of the moth’s efficiency comes from that flexibility, even though keeping wings relatively stiff is the norm for engineering larger fixed-wing craft. And those hairy surfaces? Not only can they help camouflage insects; they keep them hydrophobic so that water bounces off them. (Video and image credit: Ant Lab/A. Smith)
NASA’s Ingenuity helicopter was the first aircraft humanity has flown on another planet, and engineers are looking to make the next generation of Martian helicopters bigger and more capable. That’s challenging in Mars‘ thin atmosphere, which is only 1% as dense as Earth’s. To get adequate lift, the rotors need to spin faster there.
During Ingenuity’s mission, the team intentionally designed the craft to keep the rotor tips below supersonic speeds. But for the next mission–SkyFall–they’re looking to push the rotorcraft further. In recent tests in a Mars simulator chamber, they successfully spun the new rotors to tip speeds as high as Mach 1.08, significantly increasing the loads SkyFall could carry. (Image and video credit: NASA/JPL-Caltech; via Ars Technica)
The concrete that makes up so much of our world is usually local in origin. To keep costs low, engineers use locally-sourced ingredients to make it. But not all ingredients perform the same.
In the decades since concrete’s widespread adoption, engineers have discovered that some components in the concrete are prone to chemical reactions that cause the concrete to expand over time. For big infrastructure projects like a mid-twentieth century dam, this sparks a conundrum: how can we deal with expanding concrete without losing out on years of the project’s planned lifetime?
To find out, see what Grady learned about the Tennessee Valley Authority’s clever method for relieving a dam’s stress. (Video and image credit: Practical Engineering)
Ocean sprays, coughs, and sneezes are just a few of the ways that droplets full of bacteria and salt can get aloft on a breeze. How do these bacteria stay viable even as their droplet evaporates? That’s the question behind this video’s research.
When a bacteria-laden droplet or a salt-laden droplet dries, the evaporating droplet’s contact area shrinks, leaving behind only a concentrated lump of bacteria or salt. But when droplets contain both salt and bacteria, the drying droplet’s contact line gets pinned, leaving a larger area stain. The bacteria’s presence seems to promote crystallization of the salt, which–in turn–traps water in isolated spaces, perhaps helping the bacteria stay viable longer. (Video and image credit: R. Ran et al.)
Sprinklers have long been the go-to fire protection for commercial properties and some residences. Dousing a fire in water not only puts out the flames but cools the surroundings and helps prevent reignition. But it requires complicated infrastructure and can damage buildings and their contents. Back in 2015, students were experimenting with an alternative fire extinguisher that used sound below the range of human hearing; now a company is pitching a version of that technology for replacing sprinklers.
As described by Ars Technica, this infrasound system can detect and put out a small kitchen fire in under a minute. But fire fighting experts warn that there’s a big difference between a fire small enough for a fire extinguisher to handle and the kinds of fires sprinklers put out. With lives at stake, the burden of proof is significant for Sonic Fire Tech and any other company that wants to get their infrasound “sprinkler” system cleared for use in buildings. (Image credit: I. Azevedo; via Ars Technica)
Supersonic flight over the U.S. has been banned by all non-military aircraft for more than fifty years. The ban gained momentum in the 1960s after test programs over St. Louis and Oklahoma provoked public outcry. But NASA’s X-59 aircraft is working to lift the ban by softening the sonic booms that encouraged the ban in the first place. Although it hasn’t been tested at supersonic speeds yet, pilots are putting the sharp and skinny X-59 through its paces, slowly widening the flight envelope.
In the video above, NASA shares footage of some of the recent test flights, including various maneuvers like phugoids, banking rolls, flutter, and landing gear tests. Pay close attention to the pilot’s view and the radio chatter, and you’ll hear that they’re hovering around Mach 0.98 in some cases–just underneath the point of generating a shock wave around the aircraft. It will be neat to see what happens when they finally do go supersonic. Will it be as quiet as promised? (Video credit: NASA; image credit: NASA/L. Losey; see also NASA; via Gizmodo)
Beginning in early spring, brilliant blue ponds form on Greenland’s ice sheets as meltwater gathers in indentations. This satellite image shows the ice east of Nordenskiöld Glacier, which is the tongue of ice projecting on the left side of the image. The center region of ice is darker, marked by soot, ash, and dirt left behind after previous ice layers have melted. These darker remains make the ice less reflective to sunlight; with less reflectivity, the ice absorbs more sunlight, melting faster. (Image credit: M. Garrison/NASA Earth Observatory)
From mid-February to early May, tiny silvery Pacific herring gather along the shallow coastlines of Vancouver Island off British Columbia, Canada. In these sheltered waters, they spawn; female fish produce sticky eggs and males flood the area with milt, which turns the water a milky turquoise or green. The colors can be so vivid that the spawn is visible to satellites.
Barkley Sound, on the island’s southwestern side, frequently hosts spawning, as its rocky shoreline provides protection and the pockets of lower salinity that the fish favor. After spawning, the fish migrate back to their feeding grounds in deeper, nutrient-rich waters. (Image credit: R. Cutler; via NASA Earth Observatory)
