Enlarge / A new image from the Event Horizon Telescope has revealed powerful magnetic fields spiraling from the edge of a supermassive black hole at the center of the Milky Way, Sagittarius A*. (credit: EHT Collaboration)

Physicists have been confident since the1980s that there is a supermassive black hole at the center of the Milky Way galaxy, similar to those thought to be at the center of most spiral and elliptical galaxies. It's since been dubbed Sagittarius A* (pronounced A-star), or SgrA* for short. The Event Horizon Telescope (EHT) captured the first image of SgrA* two years ago. Now the collaboration has revealed a new polarized image (above) showcasing the black hole's swirling magnetic fields. The technical details appear in two new papers published in The Astrophysical Journal Letters. The new image is strikingly similar to another EHT image of a larger supermassive black hole, M87*, so this might be something that all such black holes share.

The only way to "see" a black hole is to image the shadow created by light as it bends in response to the object's powerful gravitational field. As Ars Science Editor John Timmer reported in 2019, the EHT isn't a telescope in the traditional sense. Instead, it's a collection of telescopes scattered around the globe. The EHT is created by interferometry, which uses light in the microwave regime of the electromagnetic spectrum captured at different locations. These recorded images are combined and processed to build an image with a resolution similar to that of a telescope the size of the most distant locations. Interferometry has been used at facilities like ALMA (the Atacama Large Millimeter/submillimeter Array) in northern Chile, where telescopes can be spread across 16 km of desert.

In theory, there's no upper limit on the size of the array, but to determine which photons originated simultaneously at the source, you need very precise location and timing information on each of the sites. And you still have to gather sufficient photons to see anything at all. So atomic clocks were installed at many of the locations, and exact GPS measurements were built up over time. For the EHT, the large collecting area of ALMA—combined with choosing a wavelength in which supermassive black holes are very bright—ensured sufficient photons.

Enlarge / Rush Rhees Library at the University of Rochester. (credit: Kickstand )

We've been following the saga of Ranga Dias since he first burst onto the scene with reports of a high-pressure, room-temperature superconductor, published in Nature in 2020. Even as that paper was being retracted due to concerns about the validity of some of its data, Dias published a second paper claiming a similar breakthrough: a superconductor that works at high temperatures but somewhat lower pressures. Shortly afterward, that got retracted as well .

On Wednesday, the University of Rochester, where Dias is based, announced that it had concluded an investigation into Dias and found that he had committed research misconduct. (The outcome was first reported by The Wall Street Journal.)

The outcome is likely to mean the end of Dias' career, as well as the company he founded to commercialize the supposed breakthroughs. But it's unlikely we'll ever see the full details of the investigation's conclusions.

Enlarge / This flexible and conductive material has “adaptive durability,” meaning it gets stronger when hit. (credit: Yue (Jessica) Wang)

Scientists are keen to develop new materials for lightweight, flexible, and affordable wearable electronics so that, one day, dropping our smartphones won't result in irreparable damage. One team at the University of California, Merced, has made conductive polymer films that actually toughen up in response to impact rather than breaking apart, much like mixing corn starch and water in appropriate amounts produces a slurry that is liquid when stirred slowly but hardens when you punch it (i.e., "oobleck"). They described their work in a talk at this week's meeting of the American Chemical Society in New Orleans.

As we've previously reported , oobleck is simple and easy to make. Mix one part water to two parts corn starch, add a dash of food coloring for fun, and you've got oobleck, which behaves as either a liquid or a solid, depending on how much stress is applied. Stir it slowly and steadily and it's a liquid. Punch it hard and it turns more solid under your fist. It's a classic example of a non-Newtonian fluid.

In an ideal fluid , the viscosity largely depends on temperature and pressure: Water will continue to flow regardless of other forces acting upon it, such as being stirred or mixed. In a non-Newtonian fluid, the viscosity changes in response to an applied strain or shearing force, thereby straddling the boundary between liquid and solid behavior. Stirring a cup of water produces a shearing force, and the water shears to move out of the way. The viscosity remains unchanged. But for non-Newtonian fluids like oobleck, the viscosity changes when a shearing force is applied.

Cicadas might be a mere inch or so long, but they eat so much that they have to pee frequently, emitting jets of urine, according to a new paper published in the Proceedings of the National Academy of Sciences. This is unusual, since similar insects are known to form more energy-efficient droplets of urine instead of jets. Adult cicadas have even been known to spray intruders with their anal jets—a thought that will certainly be with us when "double brood" cicada season begins in earnest this spring.

The science community has shown a lot of interest in the fluid dynamics of sucking insects but not as much in how they eliminate waste, according to Georgia Tech's Saad Bhamla (although Leonardo da Vinci was fascinated by jet behavior and the role of fluid cohesion in drop formation). Yet this is a critical function for any organism's ecological and metabolic regulation. So Bhamla's research has focused on addressing that shortcoming and challenging what he believes are outdated mammal-centric paradigms that supposedly govern waste elimination in various creatures.

For instance, last year, his team studied urination in the glassy-winged sharpshooter . The sharpshooter drinks huge amounts of water, piercing a plant's xylem (which transports water from the roots to stems and leaves) to suck out the sap. So sharpshooters pee frequently, expelling as much as 300 times their own body weight in urine every day. Rather than producing a steady stream of urine, sharpshooters form drops of urine at the anus and then catapult those drops away from their bodies at remarkable speeds, boasting accelerations 10 times faster than a Lamborghini.

Enlarge / Japanese artist Akiko Nakayama manipulates alcohol and inks to create tree-like dendritic patterns during a live painting session. (credit: Akiko Nakayama/CC BY )

Dendritic painting is an artistic technique that involves depositing mixtures of ink and rubbing alcohol onto paint spread on a substrate, producing branching, tree-like patterns. Two physicists have now analyzed the underlying fluid dynamics at work to create those intricate shapes and patterns, describing their findings in a new paper published in the Proceedings of the National Academy of Sciences Nexus.

“Painters have often employed fluid mechanics to craft unique compositions," said co-author Eliot Fried of the Okinawa Institute of Science and Technology (OIST) in Japan. "We have seen it with [Mexican muralist] David Alfaro Siqueiros, Jackson Pollock, and Naoko Tosa, just to name a few. In our laboratory, we reproduce and study artistic techniques, to understand how the characteristics of the fluids influence the final outcome."

Fried is one of several scientists intrigued by how artists exploit fluid dynamics in their work. For instance, Roberto Zenit, a physicist at the National Autonomous University of Mexico, has been studying the physics of fluids at work in those techniques for several years, concluding that the artists were "intuitive physicists," using science to create timeless art—including Siqueiros' "accidental painting" technique .

We've been following the annual Dance Your PhD contest for several years now, delighting in the many creative approaches researchers have devised to adapt their doctoral theses into movement—from "nano-sponge" materials and superconductivity to the physics of atmospheric molecular clusters and the science of COVID-19. This year's winner is Weliton Menário Costa of the Australian National University for his thesis "Personality, Social Environment, and Maternal-level Effects: Insights from a Wild Kangaroo Population." His video entry, "Kangaroo Time," is having a bit of a viral moment, charming viewers with its catchy beat and colorful, quirky mix of dance styles and personalities—both human and kangaroo.

As we reported previously , the Dance Your PhD contest was established in 2008 by science journalist John Bohannon. It was previously sponsored by Science magazine and the American Association for the Advancement of Science (AAAS) and is now sponsored by the AI company Primer, where Bohannon is the director of science. Bohannon told Slate in 2011 that he came up with the idea while trying to figure out how to get a group of stressed-out PhD students in the middle of defending their theses to let off a little steam. So he put together a dance party at Austria's Institute of Molecular Biotechnology , including a contest for whichever candidate could best explain their thesis topics with interpretive dance.

The contest was such a hit that Bohannon started getting emails asking when the next would be—and Dance Your PhD has continued ever since. It's now in its 16th year. There are four broad categories: physics, chemistry, biology, and social science, with a fairly liberal interpretation of what topics fall under each. All category winners receive $750, while Costa, as the overall champion, will receive an additional $2,000.

Enlarge / Chinguetti slice at the National Museum of Natural History. A larger meteorite reported in 1916 hasn't been spotted since. (credit: Claire H./CC BY-SA 2.0 )

In 1916, a French consular official reported finding a giant "iron hill" deep in the Sahara desert, roughly 45 kilometers (28 miles) from Chinguetti, Mauritania —purportedly a meteorite (technically a mesosiderite ) some 40 meters (130 feet) tall and 100 meters (330 feet) long. He brought back a small fragment, but the meteorite hasn't been found again since, despite the efforts of multiple expeditions, calling its very existence into question.

Three British researchers have conducted their own analysis and proposed a means of determining once and for all whether the Chinguetti meteorite really exists, detailing their findings in a new preprint posted to the physics arXiv. They contend that they have narrowed down the likely locations where the meteorite might be buried under high sand dunes and are currently awaiting access to data from a magnetometer survey of the region in hopes of either finding the mysterious missing meteorite or confirming that it likely never existed.

Captain Gaston Ripert was in charge of the Chinguetti camel corps. One day he overheard a conversation among the chameliers (camel drivers) about an unusual iron hill in the desert. He convinced a local chief to guide him there one night, taking Ripert on a 10-hour camel ride along a "disorienting" route, making a few detours along the way. He may even have been literally blindfolded, depending on how one interprets the French phrase en aveugle , which can mean either "blind" (i.e. without a compass) or "blindfolded." The 4-kilogram fragment Ripert collected was later analyzed by noted geologist Alfred Lacroix , who considered it a significant discovery. But when others failed to locate the larger Chinguetti meteorite, people started to doubt Ripert's story.