Category: Phenomena

  • A Special Trio of Clouds

    A Special Trio of Clouds

    Off the coast of Alaska, March 19th, 2026 featured a trio of fascinating clouds. Southwest of Anchorage, a cyclonic polar low twisted up from cold polar air centered over warmer waters. This particular storm boasted tropical-storm-force winds and thunderstorms in its center.

    Further west, long cloud streets formed parallel to the wind as cold dry air picked up moisture from warmer polar waters. And, finally, in the bottom left of the image, alternating vortices swirl in the wake of a rocky island, forming a beautiful von Karman vortex street. (Image credit: M. Garrison/NASA Earth Observatory)

    A trio of atmospheric phenomena appear in this satellite image off Alaska: a polar low, cloud streets, and a von Karman vortex street.

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    The Teton Dam Failure

    Engineering failures always leave us with lessons learned. The failure of Teton Dam in 1976 triggered an overhaul in how we manage dam construction and regulation. As Grady describes in this Practical Engineering video, the earthen dam was built with fundamental flaws that allowed water to carve pathways beneath and through the sediment meant to hold it. Although the dam cost $100 million to build, its failure cost the federal government over three times that in claims. (Video and image credit: Practical Engineering)

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  • Brushstrokes in Blue

    Brushstrokes in Blue

    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)

    Zoomed in satellite image showing sediment eddies swept into the ocean.
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  • Shocked Jets

    Shocked Jets

    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.)

    Research poster showing black and white images of liquid jets after a shockwave passed along the length of each jet.
    Research poster showing black and white images of liquid jets after a shock wave passed along the length of each jet.
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    Moths Taking Flight

    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)

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  • NASA Testing Supersonic Rotors for Mars

    NASA Testing Supersonic Rotors for Mars

    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)

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    Breaking a Dam to Save It

    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)

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    Drying Out Microbe-Filled Droplets

    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.)

    Animation of three droplets drying out. When all three components–water, salt, and bacteria–are in a droplet, the drying process looks very different.
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  • Infrasound Fire Suppression Goes Commercial

    Infrasound Fire Suppression Goes Commercial

    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)

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  • Seeking Quieter Supersonic Flight

    Seeking Quieter Supersonic Flight

    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)

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