Enlarge / The world’s smallest 3D-printed wineglass in silica glass (left) and an optical resonator for fiber optic telecommunication, photographed with scanning electron microscopy. The rim of the glass is smaller than the width of a human hair. (credit: KTH Royal Institute of Technology)

A team of Swedish scientists has developed a novel 3D-printing technique for silica glass that streamlines a complicated energy-intensive process. As a proof of concept, they 3D-printed the world's smallest wineglass (made of actual glass) with a rim smaller than the width of one human hair, as well as an optical resonator for fiber optic telecommunications systems—one of several potential applications for 3D-printed silica glass components. They described their new method in a recent paper in the journal Nature Communications.

“The backbone of the Internet is based on optical fibers made of glass," said co-author Kristinn Gylfason of the KTH Royal Institute of Technology in Stockholm. "In those systems, all kinds of filters and couplers are needed that can now be 3D printed by our technique. This opens many new possibilities.”

Silica glass (i.e., amorphous silicon dioxide) is one material that remains challenging for 3D printing, particularly at the microscale, according to the authors, though several methods seek to address that challenge, including stereolithography, direct ink writing, and digital light processing. Even those have only been able to achieve feature sizes on the order of several tens of micrometers, apart from one 2021 study that reported nanoscale resolution.

Enlarge (credit: audioundwerbung )

In most industrialized countries, solar panels account for only a quarter to a third of the overall cost of building a solar farm. All the other expenses—additional hardware, financing, installation, permitting, etc—make up the bulk of the cost. To make the most of all these other costs, it makes sense to pay a bit more to install efficient panels that convert more of the incoming light into electricity.

Unfortunately, the cutting edge of silicon panels is already at about 25 percent efficiency, and there's no way to push the material past 29 percent. And there's an immense jump in price between those and the sorts of specialized, hyper-efficient photovoltaic hardware we use in space.

Those pricey panels have three layers of photovoltaic materials, each tuned to a different wavelength of light. So to hit something in between on the cost/efficiency scale, it makes sense to develop a two-layer device. This week saw some progress in that regard, with two separate reports of two-layer perovskite/silicon solar cells with efficiencies of well above 30 percent. Right now, they don't last long enough to be useful, but they may point the way toward developing better materials.

Enlarge / Gentoo penguins are the world's fastest swimming birds, thanks to the unique shape and structure of their wings. (credit: Priya Venkatesh/CC BY-SA 3.0 )

Gentoo penguins are the world's fastest swimming birds, clocking in at maximum underwater speeds of up to 36 km/h (about 22 mph). That's because their wings have evolved into flippers ideal for moving through water (albeit pretty much useless for flying in the air). Physicists have now used computational modeling of the hydrodynamics of penguin wings to glean additional insight into the forces and flows that those wings create underwater. They concluded that the penguin's ability to change the angle of its wings while swimming is the most important variable for generating thrust, according to a recent paper published in the journal Physics of Fluids.

“Penguins’ superior swimming ability to start/brake, accelerate/decelerate, and turn swiftly is due to their freely waving wings," said co-author Prasert Prapamonthon of King Mongkut‘s Institute of Technology Ladkrabang in Bangkok, Thailand. "They allow penguins to propel and maneuver in the water and maintain balance on land. Our research team is always curious about sophisticated creatures in nature that would be beneficial to mankind.”

Scientists have long been interested in the study of aquatic animals. Such research could lead to new designs that reduce drag on aircraft or helicopters. Or it can help build more efficient bio-inspired robots for exploring and monitoring underwater environments—such as RoboKrill , a small, one-legged, 3D-printed robot designed to mimic the leg movement of krill so it can move smoothly in underwater environments.

Enlarge / Gravitational lensing has revealed a previously unknown supernova explosion more than 4 billion light-years away. (credit: Joel Johansson, Stockholm University)

Astronomers have detected a previously unknown supernova explosion more than 4 billion light-years away using a rare phenomenon called "gravitational lensing," which serves as a kind of cosmic magnifying glass. They described their discovery and its potential implications in a new paper published in the journal Nature Astronomy. Co-author Ariel Goobar, director of the Oskar Klein Center at Stockholm University, described the find as "a significant step forward in our quest to understand the fundamental forces shaping our universe."

Gravitational lensing is a direct consequence of the general theory of relativity: mass bends and warps spacetime, and light must follow that curvature. The phenomenon can form rare effects like an " Einstein ring " or an " Einstein cross ." Essentially, the distortion in space-time caused by a massive object (like a galaxy) acts as a lens to magnify an object in the background. Since these aren't perfect optical-quality lenses, there are often some distortions and unevenness. This causes the light from the background object to take different paths to Earth, and thus a single object can appear in several different locations distributed around the lens. At cosmological scales, those paths can also require light to travel very different distances to get to Earth.

Gravitational lensing helps astronomers spot celestial objects that might otherwise be too faint or far away to see, like a distant supernova, which can lead to other interesting questions. For example, last year , astronomers analyzed a Hubble image from 2010, where the image happened to also capture a supernova. Because of gravitational lensing, the single event showed up at three different locations within Hubble's field of view. Thanks to the quirks of how this lensing works, and because light travels at a finite speed, all three of the locations captured different times after the star's explosion, allowing researchers to piece together the time course following the supernova, even though it had been observed over a decade earlier.

Enlarge / Two Russian Ships of the Line Saluting by Christoffer Wilhelm Eckersberg (1827), a leading artist of the Danish Golden Age. (credit: Public domain)

Learning more about the materials used on historical paintings—paints, pigments, varnishes, and primers used to prepare canvases—is critical to ongoing conservation efforts. Apparently, many artists of the so-called Danish Golden Age used beer byproducts from local breweries to prime their canvases, according to the results of a proteomics analysis described in a recent paper published in the journal Science Advances.

A number of analytical techniques have emerged over the last few decades to create "historical molecular records" (as the authors phrase it) of the culture in which various artworks were created. For instance, studying the microbial species that congregate on works of art may lead to new ways to slow down the deterioration of priceless aging art.

Case in point: scientists analyzed the microbes found on seven of Leonardo da Vinci 's drawings in 2020 using a third-generation sequencing method known as Nanopore, which uses protein nanopores embedded in a polymer membrane for sequencing. They combined the Nanopore sequencing with a whole-genome-amplification protocol and found that each drawing had its own unique microbiome.

Enlarge / Hand-colored lithograph published by Currier & Ives in 1876, probably the most widely distributed illustration of Benjamin Franklin's kite experiment. Franklin is wrongly shown to be holding the string in one hand above where the key is attached. (credit: Public domain)

Most Americans are familiar with the story of Benjamin Franklin and his famous 18th century experiment in which he attached a metal key to a kite during a thunderstorm to see if the lightning would pass through the metal. That's largely due to many iconic illustrations commemorating the event that found their way into the popular imagination and became part of our shared cultural lore. But most of those classic illustrations are riddled with historical errors, according to a new paper published in the journal Science and Education.

Franklin's explorations into electricity began as he was approaching 40 years old after his thriving career as an entrepreneur in the printing business. His scientific interest was piqued in 1743 when he saw a demonstration by scientist/showman Archibald Spencer , known for performing various amusing parlor tricks involving electricity. He soon started a correspondence with a British botanist named Peter Collinson and began reproducing some of Spencer's impressive parlor tricks in his own home.

He would have guests rub a tube to create static and then have them kiss, producing an electrical shock. He designed a fake spider suspended by two electrified wires so that it seemed to swing back and forth of its own accord. And he devised a game dubbed "Treason," whereby he wired up a portrait of King George so that anyone who touched the monarch's crown would be shocked. And he once infamously shocked himself while trying to kill a turkey with electricity.

Enlarge (credit: NASA/SDO )

How, exactly, living things emerged on Earth remains a mystery. Now a new experiment has revealed that blasts of solar particles could have kickstarted the process by creating some of the basic components of life.

Time in the sun

Before so much as the first microbe existed, there had to be amino acids thought to have formed in one of the primordial oozes of early Earth. It was previously thought that lightning might have supercharged the formation of amino acids. However, Kensei Kobayashi of Yokohama National University in Japan, along with astrophysicist Vladimir Airapetian of NASA’s Goddard Space Flight Center and a team of researchers from both institutions, have found another possibility: The young Sun’s superflares probably helped give rise to the stuff of life.

“[Galactic cosmic rays] and [solar energetic particle] events from the young Sun represent the most effective energy sources for the prebiotic formation of biologically important organic compounds,” the researchers said in a study recently published in Life .

Enlarge / "Backlit" image of Saturn and its rings, taken by the Cassini spacecraft in 2006. (credit: NASA/Public domain)

Astronomers had long assumed that Saturn's distinctive rings formed around the same time as the planet some 4.5 billion years ago in the earliest days of our Solar System. That assumption received a serious challenge from a 2019 analysis of data collected by NASA's Cassini spacecraft, suggesting that the rings were just 10 million to 100 million years ago—a mere blink of an eye on cosmic time scales. Now, a fresh analysis of data on how much dust has accumulated on the rings confirms that controversial finding, according to a new paper published in the journal Science Advances.

"In a way, we’ve gotten closure on a question that started with James Clerk Maxwell,” said co-author Sascha Kempf , an astronomer at the University of Colorado, Boulder. In 1610, Galileo Galilei was the first to observe the rings, though his telescope was too crude to identify them as actual rings. He described them as "Saturn's ears" since they looked like two smaller planets on either side of Saturn. Galileo was bemused when the "ears" vanished in 1612 as the Earth passed through the ring plane, even more so when they became visible again the following year.

Christopher Wren suspected that Saturn had a ring in 1657, though Christiaan Huygens beat him to publication, suggesting the ring was detached from the planet in his 1659 treatise System Saturnium , which also noted his discovery of Saturn's moon, Titan. Robert Hooke noticed shadows on the rings. By 1675, Giovanni Cassini had figured out that the ring was a series of smaller rings with gaps between them. Over a century later, Pierre-Simon Laplace would mathematically demonstrate that any solid ring would be unstable. Maxwell determined that the "ring" had to be made up of lots of small particles, all independently orbiting Saturn, confirmed by observations in 1859. We now know those particles are almost entirely made up of water ice.

Enlarge / The quantum network is a bit bulkier than Ethernet. (credit: ETH Zurich / Daniel Winkler )

A new experiment uses superconducting qubits to demonstrate that quantum mechanics violates what's called local realism by allowing two objects to behave as a single quantum system no matter how large the separation between them. The experiment wasn't the first to show that local realism isn't how the Universe works—it's not even the first to do so with qubits.

But it's the first to separate the qubits by enough distance to ensure that light isn't fast enough to travel between them while measurements are made. And it did so by cooling a 30-meter-long aluminum wire to just a few microKelvin. Because the qubits are so easy to control, the experiment provides a new precision to these sorts of measurements. And the hardware setup may be essential for future quantum computing efforts.

Getting real about realism

Albert Einstein was famously uneasy with some of the consequences of quantum entanglement. If quantum mechanics were right, then a pair of entangled objects would behave as a single quantum system no matter how far apart the objects were. Altering the state of one of them should instantly alter the state of the second, with the change seemingly occurring faster than light could possibly travel between the two objects. This, Einstein argued, almost certainly had to be wrong.