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Aujourd’hui — 28 mars 2024Ars Technica

Quantum computing progress: Higher temps, better error correction

conceptual graphic of symbols representing quantum states floating above a stylized computer chip.

Enlarge (credit: vital)

There's a strong consensus that tackling most useful problems with a quantum computer will require that the computer be capable of error correction. There is absolutely no consensus, however, about what technology will allow us to get there. A large number of companies, including major players like Microsoft, Intel, Amazon, and IBM, have all committed to different technologies to get there, while a collection of startups are exploring an even wider range of potential solutions.

We probably won't have a clearer picture of what's likely to work for a few years. But there's going to be lots of interesting research and development work between now and then, some of which may ultimately represent key milestones in the development of quantum computing. To give you a sense of that work, we're going to look at three papers that were published within the last couple of weeks, each of which tackles a different aspect of quantum computing technology.

Hot stuff

Error correction will require connecting multiple hardware qubits to act as a single unit termed a logical qubit. This spreads a single bit of quantum information across multiple hardware qubits, making it more robust. Additional qubits are used to monitor the behavior of the ones holding the data and perform corrections as needed. Some error correction schemes require over a hundred hardware qubits for each logical qubit, meaning we'd need tens of thousands of hardware qubits before we could do anything practical.

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Event Horizon Telescope captures stunning new image of Milky Way’s black hole

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*.

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.

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À partir d’avant-hierArs Technica

Report: Superconductivity researcher found to have committed misconduct

Image of a large lawn, with a domed building flanked by trees and flagpoles at its far end.

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.

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This stretchy electronic material hardens upon impact just like “oobleck”

This flexible and conductive material has “adaptive durability,” meaning it gets stronger when hit.

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.

"Polymer-based electronics are very promising," said Di Wu, a postdoc in materials science at UCM. "We want to make the polymer electronics lighter, cheaper, and smarter. [With our] system, [the polymers] can become tougher and stronger when you make a sudden movement, but... flexible when you just do your daily, routine movement. They are not constantly rigid or constantly flexible. They just respond to your body movement."

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.

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Cicadas pee in jets, not droplets. Here’s why that’s kinda weird.

Cicadas' unique urination unlocks new understanding of fluid dynamics. Credit: Georgia Tech (Saad Bhamla/Elio Challita).

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.

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Study: Conflicting values for Hubble Constant not due to measurement error

This image of NGC 5468, a galaxy located about 130 million light-years from Earth, combines data from the Hubble and James Webb space telescopes.

Enlarge / This image of NGC 5468, about 130 million light-years from Earth, combines data from the Hubble and Webb space telescopes. (credit: NASA/ESA/CSA/STScI/A. Riess (JHU))

Astronomers have made new measurements of the Hubble Constant, a measure of how quickly the Universe is expanding, by combining data from the Hubble Space Telescope and the James Webb Space Telescope. Their results confirmed the accuracy of Hubble's earlier measurement of the Constant's value, according to their recent paper published in The Astrophysical Journal Letters, with implications for a long-standing discrepancy in values obtained by different observational methods known as the "Hubble tension."

There was a time when scientists believed the Universe was static, but that changed with Albert Einstein's general theory of relativity. Alexander Friedmann published a set of equations in 1922 showing that the Universe might actually be expanding, with Georges Lemaitre later making an independent derivation to arrive at that same conclusion. Edwin Hubble confirmed this expansion with observational data in 1929. Prior to this, Einstein had been trying to modify general relativity by adding a cosmological constant in order to get a static universe from his theory; after Hubble's discovery, legend has it, he referred to that effort as his biggest blunder.

As previously reported, the Hubble Constant is a measure of the Universe's expansion expressed in units of kilometers per second per megaparsec. So, each second, every megaparsec of the Universe expands by a certain number of kilometers. Another way to think of this is in terms of a relatively stationary object a megaparsec away: Each second, it gets a number of kilometers more distant.

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Meet the winners of the 2024 Dance Your PhD Contest

Weliton Menário Costa of the Australian National University won the 2024 Dance Your PhD contest with "Kangaroo Time."

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.

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A giant meteorite has been lost in the desert since 1916—here’s how we might find it

Chinguetti slice at the National Museum of Natural History

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.

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Newly spotted black hole has mass of 17 billion Suns, adding another daily

Artist's view of a tilted orange disk with a black object at its center.

Enlarge (credit: ESO/M. Kornmesser)

Quasars initially confused astronomers when they were discovered. First identified as sources of radio-frequency radiation, later observations showed that the objects had optical counterparts that looked like stars. But the spectrum of these ostensible stars showed lots of emissions at wavelengths that didn't seem to correspond to any atoms we knew about.

Eventually, we figured out these were spectral lines of normal atoms but heavily redshifted by immense distances. This means that to appear like stars at these distances, these objects had to be brighter than an entire galaxy. Eventually, we discovered that quasars are the light produced by an actively feeding supermassive black hole at the center of a galaxy.

But finding new examples has remained difficult because, in most images, they continue to look just like stars—you still need to obtain a spectrum and figure out their distance to know you're looking at a quasar. Because of that, there might be some unusual quasars we've ignored because we didn't realize they were quasars. That's the case with an object named J0529−4351, which turned out to be the brightest quasar we've ever observed.

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Alternate qubit design does error correction in hardware

Image of a complicated set of wires and cables hooked up to copper colored metal hardware.

Enlarge (credit: Nord Quantique)

There's a general consensus that performing any sort of complex algorithm on quantum hardware will have to wait for the arrival of error-corrected qubits. Individual qubits are too error-prone to be trusted for complex calculations, so quantum information will need to be distributed across multiple qubits, allowing monitoring for errors and intervention when they occur.

But most ways of making these "logical qubits" needed for error correction require anywhere from dozens to over a hundred individual hardware qubits. This means we'll need anywhere from tens of thousands to millions of hardware qubits to do calculations. Existing hardware has only cleared the 1,000-qubit mark within the last month, so that future appears to be several years off at best.

But on Thursday, a company called Nord Quantique announced that it had demonstrated error correction using a single qubit with a distinct hardware design. While this has the potential to greatly reduce the number of hardware qubits needed for useful error correction, the demonstration involved a single qubit—the company doesn't even expect to demonstrate operations on pairs of qubits until later this year.

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Searching in infrared finds a big collection of black hole star destruction

Artist's concept not a star being pulled apart, with its material forming a glowing ring around a black hole.

Enlarge (credit: NRAO/AUI/NSF/NASA)

Virtually anything in space could be a potential meal for a supermassive black hole, and that includes entire stars. Even stars much bigger than our Sun can fall victim to the black hole’s extreme gravity and be pulled in toward its gaping maw. It is a terrifying phenomenon, but how often does it really happen?

Tidal disruption events (TDEs)—when the tidal forces of a black hole overwhelm a star’s gravity and tear it apart—are thought to occur once every 10,000 to 100,000 years in any given galaxy. TDEs can be detected by the immense amounts of energy they give off. While observations of them are still pretty rare, an international team of researchers has now discovered a whopping 18 of them that previous searches had missed. Why?

Many TDEs can be found in dusty galaxies. Dust obscures many wavelengths of radiation, from optical to X-rays, but long infrared wavelengths are much less susceptible to scattering and absorption. When the team checked galaxies in the infrared, they found 18 TDEs that had eluded astronomers before.

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Mathematicians finally solved Feynman’s “reverse sprinkler” problem

Light-scattering microparticles reveal the flow pattern for the reverse (sucking) mode of a sprinkler, showing vortices and complex flow patterns forming inside the central chamber. Credit: K. Wang et al., 2024

A typical lawn sprinkler features various nozzles arranged at angles on a rotating wheel; when water is pumped in, they release jets that cause the wheel to rotate. But what would happen if the water were sucked into the sprinkler instead? In which direction would the wheel turn then, or would it even turn at all? That's the essence of the "reverse sprinkler" problem that physicists like Richard Feynman, among others, have grappled with since the 1940s. Now, applied mathematicians at New York University think they've cracked the conundrum, per a recent paper published in the journal Physical Review Letters—and the answer challenges conventional wisdom on the matter.

“Our study solves the problem by combining precision lab experiments with mathematical modeling that explains how a reverse sprinkler operates,” said co-author Leif Ristroph of NYU’s Courant Institute. “We found that the reverse sprinkler spins in the ‘reverse’ or opposite direction when taking in water as it does when ejecting it, and the cause is subtle and surprising.”

Ristroph's lab frequently addresses these kinds of colorful real-world puzzles. For instance, back in 2018, Ristroph and colleagues fine-tuned the recipe for the perfect bubble based on experiments with soapy thin films. (You want a circular wand with a 1.5-inch perimeter, and you should gently blow at a consistent 6.9 cm/s.) In 2021, the Ristroph lab looked into the formation processes underlying so-called "stone forests" common in certain regions of China and Madagascar. These pointed rock formations, like the famed Stone Forest in China's Yunnan Province, are the result of solids dissolving into liquids in the presence of gravity, which produces natural convective flows.

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The physics of an 18th-century fire engine

Oldest known fire engine by Richard Newsham

Enlarge / An 18th-century fire engine designed and built by Richard Newsham, purchased in 1728 for St Giles Church, Great Wishford, UK. (credit: Trish Steel/CC BY-SA 2.0)

When Don Lemon, a physicist at Bethel College in Kansas, encountered an 18th-century fire engine designed by English Inventor Richard Newsham on display at the Hall of Flame museum in Phoenix, he was intrigued by its pump mechanism. That curiosity inspired him to team up with fellow physicist Trevor Lipscombe of Catholic University of America in Washington, DC, to examine the underlying fluid mechanics and come up with a simple analytical model. Their analysis, described in a new paper published in the American Journal of Physics, yielded insight into Newsham's innovative design, which incorporated a device known as a "windkessel."

A quick Google search on the "windkessel effect" yields an entry on a physiological term to describe heart-aorta blood delivery, dating back to the man who coined it in 1899: German physiologist Otto Frank. "Windkessel" is German for "wind chamber," but the human circulatory system doesn't have a literal wind chamber, so Frank's use was clearly metaphorical. However, there are earlier English uses of the wind chamber terminology that refer to an airtight chamber attached to a piston-driven water pump to smooth the outflow of water in fire engines like those designed by Newsham, per Lemon and Newsham.

Rudimentary firefighting devices have been around since at least 2 BCE, when Ctesibius of Alexandria invented the first fire pump; it was re-invented in 16th-century Europe. Following the 1666 fire that destroyed much of London, there was a pressing need for more efficient firefighting strategies. This eventually led to the invention of so-called "sucking worm engines": leather hoses attached to manually operated pumps. John Lofting is usually credited with inventing, patenting, and marketing these devices, which pulled water from a reservoir while the hose ("worm") enabled users to pump that water in a supposedly continuous stream, the better to combat fires. But nothing is known of his sucking worms after 1696.

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Scientists make non-toxic quantum dots for shortwave infrared image sensors

Vials of Quantum dots with gradually stepping emission from violet to deep red

Enlarge / Vials of quantum dots with gradually stepping emission from violet to deep red. (credit: Antipoff/CC BY-SA 3.0)

Shortwave infrared light (SWIR) sensors are desirable in a broad range of applications, particularly in the service robotics, automotive, and consumer electronics sectors. Colloidal quantum dots tuned to SWIR show promise for such sensors since they can be easily integrated into CMOS, but their mass market use has been hampered by the fact that most contain toxic heavy metals like lead or mercury. Now a team of scientists has manufactured quantum dots out of non-toxic materials and tested them in a fabricated lab-scale photodetector, according to a recent paper published in the journal Nature Photonics.

"SWIR light for sensing and imaging is of paramount importance owing to its unique characteristics," the authors wrote. "It is eye safe; it can penetrate through fog, haze, and other atmospheric conditions, enabling imaging under adverse weather for automotive applications, environmental, and remote sensing; the presence of night glow under night in the SWIR range enables passive night vision; and visual imaging combined with infrared spectroscopy enables machine vision, bio imaging, and food and process quality inspection," among other applications.

As previously reported, a quantum dot is a small semiconducting bead a few tens of atoms in diameter. Billions could fit on the head of a pin, and the smaller you can make them, the better. At those small scales, quantum effects kick in and give the dots superior electrical and optical properties. They glow brightly when zapped with light, and the color of that light is determined by the size of the quantum dots. Bigger dots emit redder light; smaller dots emit bluer light. So you can tailor quantum dots to specific frequencies of light just by changing their size.

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Astronomers found ultra-hot, Earth-sized exoplanet with a lava hemisphere

Like Kepler-10 b, illustrated above, the exoplanet HD 63433 d is a small, rocky planet in a tight orbit of its star.

Enlarge / Like Kepler-10 b, illustrated above, newly discovered exoplanet HD 63433 d is a small, rocky planet in a tight orbit of its star. (credit: NASA/Ames/JPL-Caltech/T. Pyle)

Astronomers have discovered an unusual Earth-sized exoplanet they believe has a hemisphere of molten lava, with its other hemisphere tidally locked in perpetual darkness. Co-authors and study leaders Benjamin Capistrant (University of Florida) and Melinda Soares-Furtado (University of Wisconsin-Madison) presented the details yesterday at a meeting of the American Astronomical Society in New Orleans. An associated paper has just been published in The Astronomical Journal. Another paper published today in the journal Astronomy and Astrophysics by a different group described the discovery of a rare small, cold exoplanet with a massive outer companion 100 times the mass of Jupiter.

As previously reported, thanks to the massive trove of exoplanets discovered by the Kepler mission, we now have a good idea of what kinds of planets are out there, where they orbit, and how common the different types are. What we lack is a good sense of what that implies in terms of the conditions on the planets themselves. Kepler can tell us how big a planet is, but it doesn't know what the planet is made of. And planets in the "habitable zone" around stars could be consistent with anything from a blazing hell to a frozen rock.

The Transiting Exoplanet Survey Satellite (TESS) was launched with the intention of helping us figure out what exoplanets are actually like. TESS is designed to identify planets orbiting bright stars relatively close to Earth, conditions that should allow follow-up observations to figure out their compositions and potentially those of their atmospheres.

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Astronomers think they finally know origin of enormous “cosmic smoke rings“

Odd radio circles, like ORC 1 pictured above, are large enough to contain galaxies in their centers and reach hundreds of thousands of light years across.

Enlarge / Odd radio circles are large enough to contain galaxies in their centers and reach hundreds of thousands of light years across. (credit: Jayanne English / University of Manitoba)

The discovery of so-called "odd radio circles" several years ago had astronomers scrambling to find an explanation for these enormous regions of radio waves so far-reaching that they have galaxies at their centers. Scientists at the University of California, San Diego, think they have found the answer: outflowing galactic winds from exploding stars in so-called "starburst" galaxies. They described their findings in a new paper published in the journal Nature.

“These galaxies are really interesting,” said Alison Coil of the University of California, San Diego. “They occur when two big galaxies collide. The merger pushes all the gas into a very small region, which causes an intense burst of star formation. Massive stars burn out quickly, and when they die, they expel their gas as outflowing winds.”

As reported previously, the discovery arose from the Evolutionary Map of the Universe (EMU) project, which aims to take a census of radio sources in the sky. Several years ago, Ray Norris, an astronomer at Western Sydney University and CSIRO in Australia, predicted the EMU project would make unexpected discoveries. He dubbed them "WTFs." Anna Kapinska, an astronomer at the National Radio Astronomy Observatory (NRAO) was browsing through radio astronomy data collected by CSIRO's Australian Square Kilometer Array Pathfinder (ASKAP) telescope when she noticed several strange shapes that didn't seem to resemble any known type of object. Following Norris' nomenclature, she labeled them as possible WTFs. One of those was a picture of a ghostly circle of radio emission, "hanging out in space like a cosmic smoke ring."

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Quantum computing startup says it will beat IBM to error correction

The current generation of hardware, which will see rapid iteration over the next several years.

Enlarge / The current generation of hardware, which will see rapid iteration over the next several years. (credit: QuEra)

On Tuesday, the quantum computing startup Quera laid out a road map that will bring error correction to quantum computing in only two years and enable useful computations using it by 2026, years ahead of when IBM plans to offer the equivalent. Normally, this sort of thing should be dismissed as hype. Except the company is Quera, which is a spinoff of the Harvard Universeity lab that demonstrated the ability to identify and manage errors using hardware that's similar in design to what Quera is building.

Also notable: Quera uses the same type of qubit that a rival startup, Atom Computing, has already scaled up to over 1,000 qubits. So, while the announcement should be viewed cautiously—several companies have promised rapid scaling and then failed to deliver—there are some reasons it should be viewed seriously as well.

It’s a trap!

Current qubits, regardless of their design, are prone to errors during measurements, operations, or even when simply sitting there. While it's possible to improve these error rates so that simple calculations can be done, most people in the field are skeptical it will ever be possible to drop these rates enough to do the elaborate calculations that would fulfill the promise of quantum computing. The consensus seems to be that, outside of a few edge cases, useful computation will require error-corrected qubits.

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Study: The best free-throw shooters share these biomechanical traits

There's rarely time to write about every cool science-y story that comes our way. So this year, we're once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2020, each day from December 25 through January 5. Today: Using markerless motion capture technology to determine what makes the best free throw shooters in basketball.

Markerless motion-capture technology shows the biomechanics of free-throw shooters. Credit: Jayhawk Athletic Peformance Laboratory.

Basketball season is in full swing, and in a close game, the team that makes the highest percentage of free throws can often eke out the win. A better understanding of the precise biomechanics of the best free-throw shooters could translate into critical player-performance improvement. Researchers at the University of Kansas in Lawrence used markerless motion-capture technology to do just that, reporting their findings in an August paper published in the journal Frontiers in Sports and Active Living.

“We’re very interested in analyzing basketball shooting mechanics and what performance parameters differentiate proficient from nonproficient shooters,” said co-author Dimitrije Cabarkapa, director of the Jayhawk Athletic Performance Laboratory at the University of Kansas. “High-speed video analysis is one way that we can do that, but innovative technological tools such as markerless motion capture systems can allow us to dig even deeper into that. In my opinion, the future of sports science is founded on using noninvasive and time-efficient testing methodologies.”

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These scientists explored the good vibrations of the bundengan and didgeridoo

Indonesian performers onstage with one playing a bundengan

Enlarge / The bundengan (left) began as a combined shelter/instrument for duck hunters but it is now often played onstage. (credit: Utrezz0707/CC BY-SA 4.0)

There's rarely time to write about every cool science-y story that comes our way. So this year, we're once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2020, each day from December 25 through January 5. Today: the surprisingly complex physics of two simply constructed instruments: the Indonesian bundengan and the Australian Aboriginal didgeridoo (or didjeridu).

The bundengan is a rare, endangered instrument from Indonesia that can imitate the sound of metallic gongs and cow-hide drums (kendangs) in a traditional gamelan ensemble. The didgeridoo is an iconic instrument associated with Australian Aboriginal culture that produces a single, low-pitched droning note that can be continuously sustained by skilled players. Both instruments are a topic of scientific interest because their relatively simple construction produces some surprisingly complicated physics. Two recent studies into their acoustical properties were featured at an early December meeting of the Acoustical Society of America, held in Sydney, Australia, in conjunction with the Australian Acoustical Society.

The bundengan originated with Indonesian duck hunters as protection from rain and other adverse conditions while in the field, doubling as a musical instrument to pass the time. It's a half-dome structure woven out of bamboo splits to form a lattice grid, crisscrossed at the top to form the dome. That dome is then coated with layers of bamboo sheaths held in place with sugar palm fibers. Musicians typically sit cross-legged inside the dome-shaped resonator and pluck the strings and bars to play. The strings produce metallic sounds while the plates inside generate percussive drum-like sounds.

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Watch sand defy gravity and flow uphill thanks to “negative friction”

There's rarely time to write about every cool science-y story that comes our way. So this year, we're once again running a special Twelve Days of Christmas series of posts, highlighting one science story that fell through the cracks in 2023, each day from December 25 through January 5. Today: how applying magnetic forces to individual "micro-roller" particles spurs collective motion, producing some pretty counter-intuitive results.

We intuitively understand that the sand pouring through an hourglass, for example, forms a neat roughly pyramid-shaped pile at the bottom, in which the grains near the surface flow over an underlying base of stationary particles. Avalanches and sand dunes exhibit similar dynamics. But scientists at Lehigh University in Pennsylvania have discovered that applying a magnetic torque can actually cause sand-like particles to collectively flow uphill in seeming defiance of gravity, according to a September paper published in the journal Nature Communications.

Sand is pretty fascinating stuff from a physics standpoint. It's an example of a granular material, since it acts both like a liquid and a solid. Dry sand collected in a bucket pours like a fluid, yet it can support the weight of a rock placed on top of it, like a solid, even though the rock is technically denser than the sand. So sand defies all those tidy equations describing various phases of matter, and the transition from flowing "liquid" to a rigid "solid" happens quite rapidly. It's as if the grains act as individuals in the fluid form, but are capable of suddenly banding together when solidarity is needed, achieving a weird kind of "strength in numbers" effect.

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Science lives here: take a virtual tour of the Royal Institution in London

The exterior of the Royal Institution

Enlarge / The Royal Institution was founded in 1799 and is still located in the same historic building at 21 Albermarle Street in London. (credit: Griffindor/CC BY-SA 3.0)

If you're a fan of science, and especially science history, no trip to London is complete without visiting the Royal Institution, browsing the extensive collection of artifacts housed in the Faraday Museum and perhaps taking in an evening lecture by one of the many esteemed scientists routinely featured—including the hugely popular annual Christmas lectures. (The lecture theater may have been overhauled to meet the needs of the 21st century but walking inside still feels a bit like stepping back through time.) So what better time than the Christmas season to offer a virtual tour of some of the highlights contained within the historic walls of 21 Albemarle Street?

The Royal Institution was founded in 1799 by a group of leading British scientists. This is where Thomas Young explored the wave theory of light (at a time when the question of whether light was a particle or wave was hotly debated); John Tyndall conducted experiments in radiant heat; Lord Rayleigh discovered argon; James Dewar liquified hydrogen and invented the forerunner of the thermos; and father-and-son duo William Henry and William Lawrence Bragg invented x-ray crystallography.

No less than 14 Nobel laureates have conducted ground-breaking research at the Institution over the ensuing centuries, but the 19th century physicist Michael Faraday is a major focus. In fact, there is a full-sized replica of Faraday's magnetic laboratory—where he made so many of his seminal discoveries—in the original basement room where he worked, complete with an old dumbwaiter from when the room was used as a servant's hall. Its arrangement is based on an 1850s painting by one of Faraday's friends and the room is filled with objects used by Faraday over the course of his scientific career.

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Galaxy-scale winds spotted in the distant Universe

Image of a galaxy with a purple blob superimposed on its center.

Enlarge / X-ray emissions (purple) superimposed on a visible light image of a galaxy shows the galaxy winds being launched. CREDIT: X-ray: NASA/CXC/Ohio StateH-alpha and Optical: NSF/NOIRLab/AURA/KPNO/CTIO; Infrared: NASA/JPL-Caltech/Spitzer/ Optical: ESO/La Silla Observatory.

One of the ways massive stars, those at least 10-times bigger than the Sun, reach their end is in a supernova—an enormous explosion caused by the star’s core running out of fuel.

One consequence of a supernova is the production of galactic winds, which play a key role in regulating star formation. Although galactic winds have already been observed in several nearby galaxies, a team of scientists has now made the first direct observations of this phenomenon in a large population of galaxies in the distant Universe, at a time when galaxies are in their early stages of formation.

Feedback

According to the study’s lead author, Yucheng Guo, of the Centre de Recherche Astrophysique de Lyon, galactic winds are an important part of the galaxy evolution models.

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X-ray imaging of The Night Watch reveals previously unknown lead layer

The Nightwatch, or Militia Company of District II under the Command of Captain Frans Banninck Cocq (1642)

Enlarge / Rembrandt's The Night Watch underwent many chemical and mechanical alterations over the last 400 years. (credit: Public domain)

Rembrandt's The Night Watch, painted in 1642, is the Dutch master's largest surviving painting, known particularly for its exquisite use of light and shadow. A new X-ray imaging analysis of the masterpiece has revealed an unexpected lead layer, perhaps applied as a protective measure while preparing the canvas, according to a new paper published in the journal Science Advances. The work was part of the Rijksmuseum's ongoing Operation Night Watch, the largest multidisciplinary research and conservation project for Rembrandt's famous painting, devoted to its long-term preservation.

The famous scene depicted in The Night Watch—officially called Militia Company of District II under the Command of Captain Frans Banninck Cocq—was not meant to have taken place at night. Rather, the dark appearance is the result of the accumulation of dirt and varnish over four centuries, as the painting was subject to various kinds of chemical and mechanical alterations.

For instance, in 1715, The Night Watch was moved to Amsterdam’s City Hall (now the Royal Palace on Dam Square). It was too large for the new location, so the painting was trimmed on all four sides, and the trimmed pieces were never found (although in 2021, AI was used to re-create the original full painting). The objective of Operation Night Watch is to employ a wide variety of imaging and analytical techniques to better understand the materials Rembrandt used to create his masterpiece and how those materials have changed over time.

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Marbled paper, frosty fireworks among 2023 Gallery of Fluid Motion winners

Harvard University graduate student Yue Sun won a Milton Van Dyke Award for her video on the hydrodynamics of marbled paper.

Enlarge / Harvard University graduate student Yue Sun won a Milton Van Dyke Award for her video on the hydrodynamics of marbled paper. (credit: Y. Sun/Harvard University et al.)

Marbled paper is an art form that dates back at least to the 17th century, when European travelers to the Middle East brought back samples and bound them into albums. Its visually striking patterns arise from the complex hydrodynamics of paint interacting with water, inspiring a winning video entry in this year's Gallery of Fluid Motion.

The American Physical Society's Division of Fluid Dynamics sponsors the gallery each year as part of its annual meeting, featuring videos and posters submitted by scientists from all over the world. The objective is to highlight "the captivating science and often breathtaking beauty of fluid motion" and to "celebrate and appreciate the remarkable fluid dynamics phenomena unveiled by researchers and physicists."

The three videos featured here are the winners of the Milton Van Dyke Awards, which also included three winning posters. There were three additional general video winners—on the atomization of impinging jets, the emergent collective motion of condensate droplets, and the swimming motion of a robotic eel—as well as three poster winners. You can view all the 2023 entries (winning and otherwise) here.

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Study: Why a spritz of water before grinding coffee yields less waste, tastier espresso

Researchers demonstrate how adding a splash of water reduces static electricity when grinding coffee. Credit: University of Oregon

Scientific inspiration can strike at any time. For Christopher Hendon, a computational materials chemist at the University of Oregon, inspiration struck at a local coffee bar where his lab holds regular coffee hours for the Eugene campus community—a fitting venue since Hendon's research specialties include investigating the scientific principles behind really good coffee. The regulars included two volcanologists, Josef Dufek and Joshua Méndez Harper, who noted striking similarities between the science of coffee and plumes of volcanic ash, magma, and water. Thus, an unusual collaboration was born.

“It’s sort of like the start of a joke—a volcanologist and a coffee expert walk into a bar and then come out with a paper,” said Méndez Harper, a volcanologist at Portland State University. “But I think there are a lot more opportunities for this sort of collaboration, and there’s a lot more to know about how coffee breaks, how it flows as particles, and how it interacts with water. These investigations may help resolve parallel issues in geophysics—whether it’s landslides, volcanic eruptions, or how water percolates through soil.”

The result is a new paper published in the journal Matter demonstrating how adding a single squirt of water to coffee beans before grinding can significantly reduce the static electric charge on the resulting grounds. This, in turn, reduces clumping during brewing, yielding less waste and the strong, consistent flow needed to produce a tasty cup of espresso. Good baristas already employ the water trick; it's known as the Ross droplet technique, per Hendon. But this is the first time scientists have rigorously tested that well-known hack and measured the actual charge on different types of coffee.

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Unlocking the secrets of oobleck—strange stuff that’s both liquid and solid

child's hands pressing into a yellow gooey substance in a glass bowl.

Enlarge / "Oobleck" is a classic kitchen science example of a shear-thickening non-Newtonian fluid. (credit: Screenshot/PBS)

Oobleck has long been my favorite example of a non-Newtonian fluid, and I'm not alone. It's a hugely popular "kitchen science" experiment because it's 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. You can even fill small pools with the stuff and walk across it since the oobleck will harden every time you step down—a showy physics demo that naturally shows up a lot on YouTube.

The underlying physics principles of this simple substance are surprisingly nuanced and complex, and thus fascinating to scientists. Molecular engineers at the University of Chicago have used dense suspensions of piezoelectric nanoparticles to measure what is happening at the molecular level when oobleck transitions from liquid to solid behavior, according to a new paper published in the Proceedings of the National Academy of Sciences.

Toward the end of his life, Isaac Newton laid out the properties of an "ideal liquid." One of those properties is viscosity, loosely defined as how much friction/resistance there is to flow in a given substance. The friction arises because a flowing liquid is essentially a series of layers sliding past one another. The faster one layer slides over another, the more resistance there is; the slower one layer slides over another, the less resistance there is. But the world is not an ideal place.

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The Universe in a lab: Testing alternate cosmology using a cloud of atoms

Multicolored waves spread out within a pill-shaped area.

Enlarge / Density waves in a Bose-Einstein condensate. (credit: NASA)

In the basement of Kirchhoff-Institut für Physik in Germany, researchers have been simulating the Universe as it might have existed shortly after the Big Bang. They have created a tabletop quantum field simulation that involves using magnets and lasers to control a sample of potassium-39 atoms that is held close to absolute zero. They then use equations to translate the results at this small scale to explore possible features of the early Universe.

The work done so far shows that it’s possible to simulate a Universe with a different curvature. In a positively curved universe, if you travel in any direction in a straight line, you will come back to where you started. In a negatively curved universe, space is bent in a saddle shape. The Universe is currently flat or nearly flat, according to Marius Sparn, a PhD student at Kirchhoff-Institut für Physik. But at the beginning of its existence, it might have been more positively or negatively curved.

Around the curve

“If you have a sphere that's really huge, like the Earth or something, if you see only a small part of it, you don't know—is it closed or is it infinitely open?” said Sabine Hossenfelder, member of the Munich Center for Mathematical Philosophy. “It becomes a philosophical question, really. The only things we know come from the part of the Universe we observe. Normally, the way that people phrase it is that, for all we know, the curvature in this part of the Universe is compatible with zero.”

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Neptune-sized exoplanet is too big for its host star

Artist's conception of a planet embedded in a disk of dust.

Enlarge (credit: NASA/JPL-Caltech)

You win some, you lose some. Earlier this week, observations made by the Webb Space Telescope provided new data that supports what we thought we understood about planet formation. On Thursday, word came that astronomers spotted a large planet orbiting close to a tiny star—a star that's too small to have had enough material around it to form a planet that large.

This doesn't mean that the planet is "impossible." But it does mean that we may not fully understand some aspects of planet formation.

A big mismatch

LHS 3154 is, by any reasonable measure, a small, dim star. Imaging by the team behind the new work indicates that the red dwarf has just 11 percent of the Sun's mass. Temperature estimates place it at about 2,850 K, far lower than the Sun's 5,800 K temperature and barely warm enough to keep it out of ultracool dwarf category. (Yes, ultracool dwarfs are enough of a thing to merit their own Wikipedia entry.)

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Data from NASA’s Webb Telescope backs up ideas on planet formation

Image of an orange, circular shape, with a bright object at the center and areas of higher and lower brightness.

Enlarge / Image of a planet-forming disk, with gaps in between higher-density areas. (credit: ALMA(ESO/NAOJ/NRAO); C. Brogan, B. Saxton)

Where do planets come from? The entire process can get complicated. Planetary embryos sometimes run into obstacles to growth that leave them as asteroids or naked planetary cores. But at least one question about planetary formation has finally been answered—how they get their water.

For decades, planetary formation theories kept suggesting that planets receive water from ice-covered fragments of rock that form in the frigid outer reaches of protoplanetary disks, where light and heat from the emerging system’s star lacks the intensity to melt the ice. As friction from the gas and dust of the disk moves these pebbles inward toward the star, they bring water and other ices to planets after crossing the snow line, where things warm up enough that the ice sublimates and releases huge amounts of water vapor. This was all hypothesized until now.

NASA’s James Webb Telescope has now observed groundbreaking evidence of these ideas as it imaged four young protoplanetary disks.The telescope used its Medium-Resolution Spectrometer (MRS) of Webb’s Mid-Infrared Instrument (MIRI) to gather this data, because it is especially sensitive to water vapor. Webb found that in two of these disks, massive amounts of cold water vapor appeared past the snow line, confirming that ice sublimating from frozen pebbles can indeed deliver water to planets like ours.

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“Tasmanian Devil” event has the power of hundreds of billions of Suns

Image of a bright blue explosion with purple highlights against a dark background.

Enlarge (credit: NOIRLab/NSF/AURA/M. Garlick/M. Zamani)

What is hundreds of billions of times more powerful than the Sun, flashes on repeat with intense bursts of light, and verges on defying the laws of physics? No, it’s not your neighbors’ holiday lights glitching again. It’s an LFBOT in the depths of space.

LFBOTs (Luminous Fast Blue Optical Transients) are already quite bizarre. They erupt with blue light, radio, X-ray, and optical emissions, making them some of the brightest explosions ever seen in space, as luminous as supernovae. It is no exaggeration that they give off more energy than hundreds of billions of stars like our own. They also tend to live fast, blazing for only minutes before they burn themselves out and fade into darkness.

LFBOTs are quite rare, and in many cases their sources are unidentified. But we’ve never seen anything with the intensity of an LFBOT named AT2022tsd—aka the “Tasmanian Devil.” Its strange behavior was caught by 15 telescopes and observatories, including the W.M. Keck Observatory and NASA’s Chandra Space Telescope. Like other phenomena of its kind, it initially emitted incredible amounts of energy and then dimmed. Unlike any other LFBOT observed before, however, this one seemed to come back from the dead. It flared again—and again and again.

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The Ars guide to time travel in the movies

The selected films span several decades to show how Hollywood's treatment of time travel in Hollywood has evolved.

Enlarge / The selected films span several decades to show how Hollywood's treatment of time travel in Hollywood has evolved. (credit: Aurich Lawson | Getty Images)

Since antiquity, humans have envisioned various means of time travel into the future or the past. The concept has since become a staple of modern science fiction. In particular, the number of films that make use of time travel has increased significantly over the decades, while the real-world science has evolved right alongside them, moving from simple Newtonian mechanics and general relativity to quantum mechanics and the notion of a multiverse or more exotic alternatives like string theory.

But not all time-travel movies are created equal. Some make for fantastic entertainment but the time travel makes no scientific or logical sense, while others might err in the opposite direction, sacrificing good storytelling in the interests of technical accuracy. What we really need is a handy guide to help us navigate this increasingly crowded field to ensure we get the best of both worlds, so to speak. The Ars Guide to Time Travel in the Movies is here to help us all make better, more informed decisions when it comes to choosing our time travel movie fare.

This is not meant to be an exhaustive list; rather, we selected films that represented many diverse approaches to time travel across multiple subgenres and decades. We then evaluated each one—grading on a curve—with regard to its overall entertainment value and scientific logic, with the final combined score determining a film's spot on the overall ranking. For the “science” part of our scoring system, we specifically took three factors into account. First and foremost, does the time travel make logical sense? Second, is the physical mechanism of time travel somewhat realistic? And third, does the film use time travel in narratively interesting ways? So a movie like Looper, which makes absolutely no sense if you think about it too hard, gets points for weaving time paradoxes thoroughly into the fabric of the story.

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Meet “Amaterasu”: Astronomers detect highest energy cosmic ray since 1991

Artist’s illustration of extensive air showers induced by ultra-high-energy cosmic rays. Credit: Toshihiro Fujii/L-INSIGHT/Kyoto University

Astronomers involved with the Telescope Array experiment in Utah's West Desert have detected an ultra-high-energy cosmic ray (UHECR) with a whopping energy level of 244 EeV, according to a new paper published in the journal Science. It's the most energetic cosmic ray detected since 1991, when astronomers detected the so-called "Oh-My-God' particle, with energies of an even more impressive 320 EeV. Astronomers have dubbed this latest event the "Amaterasu" particle, after the Shinto sun goddess said to have created Japan. One might even call it the "Oh-My-Goddess" particle.

Cosmic rays are highly energetic subatomic particles traveling through space near the speed of light. Technically, a cosmic ray is just an atomic nucleus made up of a proton or a cluster of protons and neutrons. Most originate from the Sun, but others come from objects outside our solar system. When these rays strike the Earth’s atmosphere, they break apart into showers of other particles (both positively and negatively charged).

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Gamma-ray burst charged Earth’s ionosphere from 2 billion light-years away

Image of a narrow beam of material extending from a complex spherical cloud of material.

Enlarge / Artist's conception of a gamma-ray burst. (credit: NASA)

An astounding gamma-ray burst, dubbed GRB 221009A, continues to amaze even though it has been more than a year since it was detected. Scientists from Italy have recently published a study that shows how our planet’s ionosphere was impacted as a result of its high intensity and long duration.

The ionosphere is one of the Earth’s atmospheric layers, stretching from 60 km to more than 950 km in altitude. Containing electrically charged plasma, its lower half, called the bottom-side, extends until 350 km. Beyond 350 km lies the upper half, called the top-side.

Charging the top-side

According to Mirko Piersanti, who is a professor at the University of L’Aquila, gamma-ray burst effects have often been observed in the bottom-side but rarely in the top-side of the ionosphere. “That’s because the plasma density and conductivity in the top-side is much lower than the bottom-side. Also, to observe this effect, you need a satellite that can make observations, orbiting in this layer,” Piersanti said.

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Physics reveals secret of how nature helped sculpt the Great Sphinx of Giza

Frontal view of the Great Sphinx of Giza in Egypt

Enlarge / Experiments yield fresh evidence to support controversial hypothesis about the formation of the Great Sphinx of Giza. (credit: MusikAnimal/CC BY-SA 3.0)

Leif Ristroph, a physicist and applied mathematician at New York University, was conducting experiments on how clay erodes in response to flowing water when he noticed tiny shapes emerging that resembled seated lions—in essence, miniature versions of the Great Sphinx of Giza in Egypt. Further experiments provided evidence in support of a longstanding hypothesis that natural processes first created a land formation known as a yardang, after which humans added additional details to create the final statue. Initial results were first presented last year as part of the American Physical Society's Gallery of Fluid Motion, with a full paper being published this week in the journal Physical Review Fluids.

"Our results suggest that Sphinx-like structures can form under fairly commonplace conditions," Ristroph et al. wrote in their paper. "These findings hardly resolve the mysteries behind yardangs and the Great Sphinx, but perhaps they provoke us to wonder what awe-inspiring landforms ancient people could have encountered in the deserts of Egypt and why they might have envisioned a fantastic creature."

In 2018, Ristroph's applied mathematics lab fine-tuned the recipe for blowing the perfect bubble based on experiments with soapy thin films, pinpointing exactly what wind speed is needed to push out the film and cause it to form a bubble, and how that speed depends on parameters like the size of the wand. (You want a circular wand with a 1.5-inch perimeter, and you should gently blow at a consistent 6.9 cm/s.)

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Most researchers behind superconductor claim now want their paper pulled

Image of a basketball player having his shot blocked.

Enlarge / Dikembe Mutombo rejects your flawed publication. (credit: DAVID MAXWELL / Getty Images)

In a move that surprised very few people, the journal Nature retracted a paper claiming a major advance in high-temperature superconductivity. This marks the second paper the journal retracted over the objections of Ranga P. Dias, a faculty member at the University of Rochester who led the research. Or at least it's implied that he objected to this retraction, as he apparently refused to respond to Nature about the matter.

Dias' work on superconductivity has focused on hydrogen-rich chemicals that form under extreme pressures. Other research groups have shown that the pressure forces hydrogen into crystals within the material, where it encourages the formation of electron pairs that enable superconductivity. This allows these chemicals to superconduct at elevated temperatures. Dias' two papers purportedly described one chemical that could superconduct at room temperatures and extreme pressures and a second that did so under somewhat lower pressures, putting it within reach of more readily available lab equipment.

But problems with the first of these papers became apparent as the research community dug into the details of the work. Dias' team apparently used a non-standard method for calculating the background noise in a key experiment and didn't include the details of how this was done in the paper. In other words, the data in the paper looked good, but it wasn't clear whether it accurately reflected the experimental results. As a result, Nature retracted it, although all nine authors of the paper objected to this decision at the time.

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Supermassive black hole found only half a billion years after Big Bang

Image of a field of stars with a large purple glow in the center.

Enlarge / Inset shows the JWST image of the galaxy in infrared, along with the X-rays from the black hole seen by the Chandra. While the X-ray source is far smaller than the galaxy, X-rays are much harder to resolve. (credit: X-ray: NASA/CXC/SAO/Ákos Bogdán; Infrared: NASA/ESA/CSA/STScI; Image Processing: NASA/CXC/SAO/L. Frattare & K. Arcand)

Researchers combing through some of the earliest galaxies in the Universe have found one that appears to have an actively feeding central black hole. Based on the amount of radiation it's emitting, the researchers estimate that it accounts for roughly half of the mass of the entire galaxy it's in—an astonishingly high fraction compared to modern galaxies.

The fact that such a large object can exist only half a billion years after the Big Bang places severe limits on how it could possibly have formed, strongly suggesting that supermassive black holes formed without ever having gone through an intermediate step involving a star.

Old X-rays

The earliest galaxies in the Universe that we know about have been identified using the James Webb Space Telescope, which took advantage of a galaxy cluster in the foreground that magnified more distant ones through gravitational lensing. Using the lens provided by a specific cluster, the Webb identified 11 galaxies that were imaged as they existed less than a billion years after the Big Bang.

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Good news for clumsy divers: Physics holds the key to less-painful belly-flops

Brown researchers set up a belly flop-like water experiment using a blunt cylinder, adding an important vibrating twist to it that ultimately led them to counterintuitive findings. Credit: John Antolik and Daniel Harris.

We've all had the misfortune of botching a dive into the pool and ending up in a painful belly-flop—or perhaps we've done it deliberately to show off and instantly regretted that decision. Hitting the water in that body position can feel like hitting concrete and lead to bruising or (if one is falling from a greater height) internal injuries. While the basic physics is well-understood, scientists are always looking for greater insight into the phenomenon in hopes of finding novel ways to ameliorate the impact.

Scientists at Brown University have found that, surprisingly, adding a bit of extra spring to a body hitting the water can actually increase the impact force instead of decrease it under certain conditions, according to a new paper published in the Journal of Fluid Mechanics. The implications go beyond protecting divers; a better understanding of the hydrodynamics will improve designs of naval ships, seaplanes, or projectiles, as well as underwater autonomous vehicles.

From a physics standpoint, we're talking about an elastic body hitting the surface of water. The stress of moving from the medium of air to the much denser medium of water exerts a huge force as that body displaces it. The cohesive forces between water molecules are stronger at the surface, making it harder to break through. (It's why diving competitions often use aerators to create bubbles in the water, breaking the surface tension to protect the divers.) A large volume of fluid must be accelerated (displaced) in a short timeframe to match the speed of the impinging body. The larger the surface area of the object hitting the water, the more resistance there will be—and with belly-flops there will be a much larger surface area than with a simple swan dive, resulting in that signature slam.

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AI helps 3D printers “write” with coiling fluid ropes like Jackson Pollock

Jackson Pollock working in his Long Island studio adjacent to his home in 1949.

Enlarge / Jackson Pollock working in his Long Island studio adjacent to his home in 1949. (credit: Martha Holmes/The LIFE Picture Collection via Getty Image)

If you've ever drizzled honey on a piece of toast, you've noticed how the amber liquid folds and coils in on itself as it hits the toast. The same thing can happen with 3D and 4D printing if the print nozzle is too far from the printing substrate. Harvard scientists have taken a page from the innovative methods of abstract expressionist artist Jackson Pollock—aka the "splatter master"—to exploit the underlying physics rather than try to control it to significantly speed up the process, according to a new paper published in the journal Soft Matter. With the help of machine learning, the authors were able to decorate a cookie with chocolate syrup to demonstrate the viability of their new approach.

As reported previously, Pollock early on employed a "flying filament" or "flying catenary" technique before he perfected his dripping methods. The paint forms various viscous filaments that are thrown against a vertical canvas. The dripping technique involved laying a canvas flat on the floor and then pouring paint on top of it. Sometimes, he poured it directly from a can; sometimes he used a stick, knife, or brush; and sometimes he used a syringe. The artist usually "rhythmically" moved around the canvas as he worked. His style has long fascinated physicists, as evidenced by the controversy surrounding the question of whether or not Pollock's paintings show evidence of fractal patterns.

Back in 2011, Harvard mathematician Lakshminarayanan Mahadevan collaborated with art historian Claude Cernuschi on an article for Physics Today examining Pollock's use of a "coiling instability" in his paintings. The study mathematically describes how a viscous fluid folds onto itself like a coiling rope—just like pouring cold maple syrup on pancakes.

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What caused the volcanic tsunami that devastated a Greek island 373 years ago?

This view from an international volcano monitoring system shows the Kolumbo volcanic crater on the seafloor.

Enlarge / This view from an international volcano monitoring system shows the Kolumbo volcanic crater on the seafloor. (credit: SANTORY )

In 1650 CE, the Greek island of Santorini was devastated by the eruption of an underwater volcano called Kolumbo. People first noticed the water boiling and changing color and a cone poking out of the surface of the sea. Next came ejected glowing rocks, fire and lightning, fumes of thick smoke, falling pumice and ash, earthquakes, and a powerful tsunami with waves as high as 20 meters. All this eruptive activity killed around 70 people and hundreds of cattle.

These details are based on contemporary accounts compiled by French geologist Ferdinand A. Fouqué in 1879. A team of German and Greek scientists has now combined that historical knowledge with 3D seismic mapping and computer simulations to determine why the volcano's violent eruption triggered a tsunami. According to a new paper published in the journal Nature Communications, the tsunami resulted from a landslide followed by the volcanic explosion.

Located some 8 kilometers northeast of Santorini, Kolumbo also erupted around 1630 BCE with catastrophic consequences for ancient Minoan culture. Today, the volcano boasts sulfide-sulfate hydrothermal vents that are home to some rare species of microorganisms typically not found elsewhere near hydrothermal vents. And it remains active and potentially dangerous: A previously unknown magma chamber was discovered last year and is growing at a rate of around 4 million cubic meters per year. At that rate, the chamber will reach the same volume as the amount of magma ejected in the 1650 eruption within the next 150 years.

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How do kingfishers avoid concussions when diving? It might be in their genes

A diving kingfisher

Enlarge / Fish-eating kingfishers execute plunging dives into the water to capture prey, yet never seem to get concussed. (credit: Richard Towell)

There are many different species of kingfisher, and those that eat fish hunt by repeatedly diving head-first into the water when they spot tasty prey without suffering brain injuries like concussions. It turns out that diving kingfishers have several modified genes associated with diet and brain structure, according to a new paper published in the journal Communications Biology—notably mutations in genes related to the tau proteins that help stabilize neuron structure, although they can be harmful if too many build up.

“I learned a lot about tau proteins when I was the concussion manager of my son’s hockey team,” said co-author Shannon Hackett, associate curator of birds at the Field Museum. “I started to wonder, why don’t kingfishers die because their brains turn to mush? There’s gotta be something they're doing that protects them from the negative influences of repeatedly landing on their heads on the water’s surface.”

It's not the first time scientists have pondered this question, not just for kingfishers, but for other birds like gannets and woodpeckers. For instance, physicists at Virginia Tech studied diving gannets back in 2014 (publishing their conclusions in 2016), which fold their wings back as they dive, hitting the water with their whole body to snag underwater prey. From a physics standpoint, we're talking about an elastic body hitting the surface of water as fast as 55 MPH. The stress of moving from the medium of air to the much denser medium of water exerts a huge force on the bird's body, with an impact akin to tornadoes hitting the water. Yet despite the stress on their bodies, gannets (like the kingfisher) manage the feat again and again without injury, especially concussions.

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Atom Computing is the first to announce a 1,000+ qubit quantum computer

A dark blue background filled with a regular grid of lighter dots

Enlarge / The qubits of the new hardware: an array of individual atoms. (credit: Atom Computing)

Today, a startup called Atom Computing announced that it has been doing internal testing of a 1,180 qubit quantum computer and will be making it available to customers next year. The system represents a major step forward for the company, which had only built one prior system based on neutral atom qubits—a system that operated using only 100 qubits.

The error rate for individual qubit operations is high enough that it won't be possible to run an algorithm that relies on the full qubit count without it failing due to an error. But it does back up the company's claims that its technology can scale rapidly and provides a testbed for work on quantum error correction. And, for smaller algorithms, the company says it'll simply run multiple instances in parallel to boost the chance of returning the right answer.

Computing with atoms

Atom Computing, as its name implies, has chosen neutral atoms as its qubit of choice (there are other companies that are working with ions). These systems rely on a set of lasers that create a series of locations that are energetically favorable for atoms. Left on their own, atoms will tend to fall into these locations and stay there until a stray gas atom bumps into them and knocks them out.

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Planet collision explains star’s brightening, then dimming

image of an violently churning, reddish cloud of material at a distance from a star.

Enlarge / Artist's conception of what the post-collision body of material might look like. (credit: MARK GARLICK)

Planet formation is thought to be a messy process, as lots of growing planets end up in unstable orbits, resulting in large collisions like the one that resulted in the Moon's formation. The messiness may not end there, as many exosolar systems have indications that their planets migrated after their formation, creating the potential for further collisions. Again, there are indications that a similar thing happened in our own Solar System, as Jupiter and Saturn seem to have moved around before reaching their present orbits.

All the evidence for these collisions, however, is indirect or the product of modeling. Planetary migrations are too slow for us to track them, and we can't image planets that are close enough to their stars for collisions to be likely.

But a large team of scientists now think they have evidence of a smash-up of giant planets orbiting a Sun-like star. The evidence comes from a combination of two unusual events: the sudden brightening of the star at infrared wavelengths, followed over two years later by its dimming in the visual.

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Mysterious fast radio bursts might be caused by “starquakes,” study finds

Artist's impression of a fast radio burst (FRB) traveling through space and reaching Earth.

Enlarge / Artist's impression of a fast radio burst (FRB) traveling through space and reaching Earth. (credit: ESO/M. Kornmesser/CC BY 4.0)

Astronomers have been puzzling over the mysterious origins of fast radio bursts (FRBs) since they were first detected in 2007. Now scientists at the University of Tokyo have come up with new evidence that at least some FRBs may be caused by so-called "starquakes" on the surfaces of neutron stars, according to a new paper published in the Monthly Notices of the Royal Astronomical Society.

As Ars Science Editor John Timmer reported previously, FRBs involve a sudden blast of radio-frequency radiation that lasts just a few microseconds. Astronomers have cataloged hundreds of them; some come from sources that repeatedly emit FRBs, while others seem to burst once and go silent. You can produce this sort of sudden surge of energy by destroying something. But the existence of repeating sources suggests that at least some of them are produced by an object that survives the event. That has led to a focus on compact objects, like neutron stars and black holes—especially a class of neutron stars called magnetars—as likely sources.

Magnetars are an extreme form of a neutron star, a type of body that is already notable for being extreme. They are the collapsed core of a massive star, so dense that atoms get squeezed out of existence, leaving a swirling mass of neutrons and protons. That mass is roughly equal to the Sun's but compressed into a sphere with a radius of about 10 kilometers. Neutron stars are best known for powering pulsars, rapidly repeating bursts of radiation driven by the fact that these massive objects can complete a rotation in a handful of milliseconds.

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Zombie star’s strange behavior ascribed to what it’s eating

Pulsars are spinning neutron stars, the relics of massive stars gone supernova.

Enlarge / Pulsars are spinning neutron stars, the relics of massive stars gone supernova. (credit: NASA's Goddard Space Flight Center)

Some stars never really die. Pulsars are the undead magnetized cores of massive stars that have met their end in a supernova. They rotate furiously, spewing jets of electromagnetic radiation from their magnetic poles, which makes them appear to flash regularly when observed from Earth.

As if these zombies weren’t already bizarre enough, the behavior of one of them, pulsar PSR J1023+0038, has remained a mystery until now. PSR J1023 does have the usual compact jet of radiation at its poles. But it’s in a close binary system with another star, and, as it orbits this star, it has been observed blazing intensely before quickly dimming again. An international team of astronomers has finally made a breakthrough in understanding what causes the pulsar to switch from intensely bright “high mode” to dimmer “low mode” as it strips material from its companion star. Where that material goes has finally explained why it acts so erratically.

Extreme highs…

PSR J1023 is no ordinary pulsar, but a millisecond pulsar, meaning that it rotates hundreds of times per second. Even before its 2002 discovery, it was thought that millisecond pulsars get their speed from being in binary systems. Their speed comes from stripping material off their companion stars and drawing it in, which keeps feeding the neutron star more energy.

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Colorful quantum dots snag 2023 Nobel Prize in Chemistry

Vials of Quantum dots with gradually stepping emission from violet to deep red

Enlarge / Vials of quantum dots with gradually stepping emission from violet to deep red. (credit: Antipoff/CC BY-SA 3.0)

Once thought impossible to make, quantum dots have become a common component in computer monitors, TV screens, and LED lamps, among other uses. Three of the scientists who pioneered these colorful nanocrystals—Moungi G. Bawendi, Louis E. Brus, and Alexei I. Ekimov—have been awarded the 2023 Nobel Prize in Chemistry by the Royal Swedish Academy of Sciences for the discovery and synthesis of quantum dots.” The news had already leaked in the Swedish news media—a rare occurrence—when Johan Aqvist, chair of the Academy's Nobel committee for chemistry, made the official announcement, complete with five flasks containing quantum dots of many colors lined up before him as a visual aid.

A quantum dot is a small semiconducting bead a few tens of atoms in diameter. Billions could fit on the head of a pin, and the smaller you can make them, the better. At those small scales, quantum effects kick in and give the dots superior electrical and optical properties. They glow brightly when zapped with light, and the color of that light is determined by the size of the quantum dots. Bigger dots emit redder light; smaller dots emit bluer light. So, you can tailor quantum dots to specific frequencies of light just by changing their size.

Physicists had thought since the 1930s that particles at the nanoscale would behave differently. That's because, according to quantum mechanics, there is much less space for electrons when particles are that small, squeezing electrons together so tightly that material properties can change dramatically. Scientists succeeded in making nanoscale-thin films on top of bulk materials in the 1970s that had size-dependent optical properties, in keeping with those earlier predictions. But making those films required ultra-high vacuum conditions and temperatures near absolute zero, so nobody expected them to have much practical use.

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A new “time window”: Meet the winners of the 2023 Nobel Prize in Physics

drawings of two men and one woman

Enlarge / Pierre Agostini, Ferenc Krausz and Anne L'Huillier have been awarded the 2023 Nobel Prize in Physics for their work using attosecond pulses to study the dynamics of electrons inside atoms. (credit: Niklas Elmehed/Nobel Prize Outreach)

Electrons move and change energies at such a blistering speed that physicists long believed it would never be possible to capture their dynamics, even with the fastest lasers. The Royal Swedish Academy of Sciences has awarded the 2023 Nobel Prize in Physics to three scientists who used ultrafast pulses of light to do just that with a technique known as attosecond spectroscopy. Per the citation, Pierre Agostini, Ferenc Krausz, and Anne L'Huillier "have given humanity new tools for exploring the world of electrons inside atoms."

It's well known that to capture detailed images of, say, a hummingbird mid-flight, one needs to use exposure times that are shorter than a single beat of the hummingbird's wings. But atoms in a molecule move in billionths of a second, aka femtoseconds; electrons move and change energies faster, between one and a few hundred attoseconds. (An attosecond is one billionth of a billionth of a second.) If you sent a flash of light from one end of a room to the other, it would take 10 billion attoseconds. Physicists had long believed that a femtosecond was the fundamental limit for producing short bursts of light—at least with existing technology—and thus capturing the behavior of electrons in atoms was beyond reach.

That changed over the last 20 years. “The ability to generate attoseconds of light has opened the door on an extremely tiny timescale, and it also opened the door to the world of electrons,” said Eva Olsson, chair of the Nobel committee for physics, at the press conference announcing the prize. “Back in 1925, Werner Heisenberg argued that this world cannot be seen. Thanks to attosecond physics, this is now starting to change.” The work is expected to have a significant impact on electronics, where understanding and controlling how electrons behave in materials is critical to achieving faster electronics, as well as in medical diagnostics, which requires being able to identify different molecules.

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Paint drops form “fried egg” patterns if concentration, temp is just right

As paint drops dry, they can look like a “fried egg” (left image, scale bar is one millimeter) or develop a more even pigment distribution (right image).

Enlarge / As paint drops dry, they can look like a “fried egg” (left) or develop a more even pigment distribution (right). (credit: S.M.M. Ramos et al., Langmuir 2023/ACS)

French scientists have been watching paint drops dry and monitoring the resulting patterns in hopes of finding ways to better control the drying process to reduce cracks and other imperfections. They found that some drops dried uniformly, while others wound up resembling fried eggs with pigmented "yolks" at the center surrounded by white, depending on pigment concentration and temperature, according to a recent paper published in the journal Langmuir.

The underlying mechanism is akin to the so-called "coffee ring effect," when a single liquid evaporates and the solids that had been dissolved in the liquid (like coffee grounds) form a telltale ring. It happens because the evaporation occurs faster at the edge than at the center. Any remaining liquid flows outward to the edge to fill in the gaps, dragging those solids with it. Mixing in solvents (water or alcohol) reduces the effect, as long as the drops are very small. Large drops produce more uniform stains.

"Whiskey webs" are another related example. As previously reported, Princeton University physicist Howard Stone has tracked the fluid motion in whiskey drops with fluorescent markers, concluding that surfactant molecules collect at the edge of the drop. This creates a tension gradient pulling the liquid inward (known as the Marangoni effect, which is also associated with "tears of wine"). There are also plant-based polymers that stick to the glass and channel particles in the whiskey.

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