Eighteen meters long and powered only by the wind, artist Theo Jansen’s latest Strandbeest strolls the sand in this short video. Its complex movements — a swinging gait in some places and a caterpillar-like wave in others — are mesmerizing and life-like enough to almost make you wonder if the contraption truly is alive. See some of Jansen’s previous creations here. (Video and image credit: T. Jansen et al.; via Colossal)
James Bond notoriously orders his martinis “shaken, not stirred,” a request bartenders fulfill by shaking the cocktail over ice in a separate shaker. But what if you shake the martini glass itself? That’s the question that inspired this lovely mixology.
By shaking the martini glass gently back and forth (along the directions shown by the arrows in each image), the team created different mixing patterns within the glass. With a little food dye and pearl dust, they visualized the flows they found. By changing the viscosity of the cocktail and the speed of the swish, they made everything from a four-leaf clover to a cadre of ghosts. It seems that martini glasses hold a flow for every occasion! (Image and research credit: X. Song et al.; submitted by Zhao P.)
One theory suggests that the Great Sphinx of Giza formed — in part — naturally as a result of erosion, and ancient Egyptians added features to the bedrock formation. To test the plausibility of the theory, researchers made a miniature sphinx, consisting of a clay mound with a single, harder inclusion to represent the Sphinx’s head, and placed their construction in a water tunnel. As the water eroded away the clay, the head appeared, and flow around this harder-to-erode region formed some of the body and paws of the reclining Sphinx.
The experiment suggests that it is plausible for part of the Sphinx to have formed naturally, as a result of erosion. But plausibility is not proof, and given the lack of a contemporary inscription explaining the statue’s origin, the goals and methods of the people who built it around 2500 B.C.E. will remain a matter of archaeological debate. (Image credit: S. Boury et al.)
After many years of featuring work from the Gallery of Fluid Motion, I’m excited to announce a new public exhibition of art drawn from the competition: “Chaosmosis: Assigning Rhythm to the Turbulent.” Works in the exhibit come from both scientists and artists; each piece makes visible the fluid motions that surround us.
The exhibit is located at the National Academy of Sciences in Washington, DC through February 23, 2024. Entry is free, but only available between 9 a.m. and 5 p.m. on weekdays. For more, check out the exhibit’s webpage and press release (pdf) and the Instagram accounts for CPNAS and the exhibit.
I’m looking forward to seeing the exhibit when I’m at the APS DFD meeting next month, but if you can’t make it to DC before the exhibit ends, don’t worry! This is just the first stop for the new traveling GFM exhibit. (Image credits: various, see individual images’ titles)
Sprites, or red sprites, are high-altitude electrical discharges in the atmosphere. Although sometimes called upper-atmospheric lightning, sprites are a cold plasma phenomenon. They often occur in clusters, as in this photo by Angel An, which won in the Skyscapes category of the 2023 Astronomy Photographer of the Year competition. Sprites, which last only a millisecond or so, take place during intense thunderstorms, but, unlike our more familiar lightning, sprites move upward from the storm toward the ionosphere. They can occur on Venus, Saturn, and Jupiter as well, although sprites have only been observed directly on Earth and Jupiter. (Image credit: A. An; via Colossal)
Moving across sand is quite challenging for bipedal creatures like us, but other animals have their ways. Photographer Paul Lennart Schmid caught this snake on the move, with impressions of its passage still in the sand. X-ray observations of snakes moving in sand show that they swim through the granular medium. Snakes are quite efficient in their swimming, moving most of their body through the tunnel created by their head, thereby reducing their overall effort. (Image credit: P. Schmid; via Nature TTL POTY)
Mushrooms are the fruiting bodies of much bigger, largely underground fungi. Being fruit, mushrooms have the job of spreading spores so that the fungus can reproduce. Some mushrooms rely on the wind; others create their own wind. Still others use vortex rings to carry their spores higher. Who knew such fascinating and beautiful physics lies along the forest floor? (Image credit: top – A. Papatsanis, bottom – I. Potyó; via Wildlife POTY)
240 million years ago, pressure waves emanated from a black hole inside the Perseus Galaxy Cluster. Much later, NASA’s Chandra X-Ray Observatory intercepted those waves. Scientists raised the frequency of the signal until it fell within the range of human hearing. And then photographer John White played that sound through a petri dish of water sitting on a speaker. The result is above: a watery glimpse of a long ago black hole’s signature. Within these Faraday waves is the echo of a stellar phenomenon that took place when the very first dinosaurs walked our planet. (Image credit: J. White; via the 2023 Astronomy POTY)
When solar storms in late February sent energetic particles toward Earth, photographer Cari Letelier ventured to the remote northern edge of Iceland to capture the resulting auroras. When fast-moving, high-energy particles from the solar wind meet Earth’s magnetosphere, they’re directed toward the poles. There the particles slam into Earth’s upper atmosphere, exciting atoms that glow in greens, reds, and pinks. Curtains of light dance across the sky as a result. February’s show was particularly stunning, as captured by Letelier at Arctic Henge. (Image credit: C. Letelier; via Colossal)
Colorful chandeliers, passing spirits, sprouting mushrooms, and fountains of falling ink appear in Christopher Dormoy’s “Aquakosmos.” Driven by the slight density difference between ink and water, many of these elaborate shapes result from the Rayleigh-Taylor instability. Anytime you see mushroom-like plumes and chandelier-like splitting vortex rings, there’s probably a Rayleigh-Taylor instability behind it. Check out the full video above, and, if you want to give this kind of flow visualization a try yourself, a glass of water and vial of food coloring is a great place to start. (Video and image credit: C. Dormoy)