Enlarge / Blood Falls seeps from the end of the Taylor Glacier into Lake Bonney. Scientists believe a buried saltwater reservoir is partly responsible for the discoloration, which is a form of reduced iron. (credit: NSF/Peter Rejcek/Public domain)

In 1911, an Australian geologist named Thomas Griffith Taylor was exploring a valley in Antarctica when he stumbled upon a strange waterfall. The meltwater flowing from beneath the glacier that now bears Taylor's name turns a deep red upon coming into contact with the air, earning the site the moniker "Blood Falls." Various hypotheses have been proposed over the last century to explain the strange phenomenon. A team of scientists now thinks they've finally found the answer: tiny nanospheres rich in iron, silica, calcium, aluminum, and sodium, among other elements.

But why has solving this mystery taken more than a century? It seems the nanospheres are amorphous materials, meaning they lack a crystalline structure and hence eluded prior analytical methods looking for minerals because they are not, technically, minerals, according to a recent paper published in the journal Frontiers in Astronomy and Space Science. That might seem like an odd choice of journal for this study, but the Blood Falls at Taylor Glacier is a so-called "analogue" site for astrobiologists and planetary scientists keen to learn more about how life might evolve and thrive in similar inhospitable environments elsewhere in the universe.

"With the advent of the Mars Rover missions, there was an interest in trying to analyze the solids that came out of the waters of Blood Falls as if it was a Martian landing site," said co-author Ken Livi of Johns Hopkins University. "What would happen if a Mars Rover landed in Antarctica? Would it be able to determine what was causing the Blood Falls to be red? It's a fascinating question and one that several researchers were considering."

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.

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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.

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Those gummy bears from last Halloween might be hard as rocks, but a new study has used physics and chemistry to find out what factors put gummies at risk of becoming almost impossible to chew—and how to keep them gummy for as long as possible.

Keeping a gooey consistency

Gummies are all about texture. They shouldn’t be too hard, soft, or sticky, but they can become any of those things depending on ingredient content or storage (often both). Keeping them fresh means preventing changes to their internal chemistry that would otherwise occur over time. The ingredients that go into gummy candy, and how much of each is used, will inevitably affect the chemical reactions that occur, as will the temperature they are stored at and how long they stay in storage. So a team of researchers experimented with different formulas and storage methods to come up with the ultimate gummy.

The main ingredients of a gummy are glucose syrup, sucrose, starch, gelatin, and water. Led by Suzan Tireki of Ozyegin University in Turkey, the research team mixed eight batches with varying amounts of those main ingredients (flavor and color were low priorities for this work). The ratio of glucose syrup to sucrose turned out to be especially important because it has the most influence on gummy texture. Glucose is also responsible for sweetness and acts as a preservative by absorbing excess water that could otherwise attract microbes. Gelatin and starch are polymers and gelling agents that help give gummies their iconic texture.

Enlarge / A colorful, textured bi-layer film made from plant-based materials cools down when it’s in the sun. (credit: Qingchen Shen)

Summer is almost here, bringing higher temperatures and prompting many of us to crank up the air conditioning on particularly hot days. The downside to A/C is that the units gobble up energy and can emit greenhouse gases, contributing further to global warming. Hence, there is strong interest in coming up with eco-friendly alternatives. Scientists from the University of Cambridge have developed an innovative new plant-based film that gets cooler when exposed to sunlight, making it ideal for cooling buildings or cars in the future without needing any external power source. They described their work at a recent meeting of the American Chemical Society.

The technical term for this approach is passive daytime radiative cooling (PDRC), so named because it doesn't require an injection of energy into the system to disperse heat. The surface emits its own heat into space without being absorbed by the air or atmosphere, thereby becoming several degrees cooler than the surrounding air without needing electrical energy.

"We know there is spontaneous thermal transfer between objects with different temperatures," Qingchen Shen said at a press conference during the meeting. Their cooling technology exploits that thermal transfer, with a twist. Most PDRC materials (paints, films, and so forth) are white, or have a mirrored finish, to achieve a broadband reflection of sunlight. Pigments or dyes interfere with that since they absorb specific wavelengths of light and only reflect certain colors, thereby transforming energy from the light into heat. The films created by Shen et al . are colored, but it is structural color in the form of nanocrystals, not due to adding pigments or dyes. So color can be added without sacrificing the passive cooling efficiency.

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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 .

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Can you tell me how many batteries you use in a year? A report from the University of Illinois reveals that Americans buy about 3 billion dry-cell batteries annually, which means that an average American ends up using nearly 10 batteries a year. Of course, this shouldn’t come as a surprise given that almost everything we use runs on batteries. What’s shocking is that out of these billions of batteries, about 2,500 end up in the stomachs of kids.

Almost every day, there are numerous cases of kids swallowing batteries that power their toys, watches, or gadgets; this results in many cases of internal injuries or stomach infections.

A team of researchers at the Italian Institute of Technology (IIT) in Milan recently created a fully rechargeable battery using nontoxic edible components. This is probably the world’s first battery that is safe to ingest and entirely made of food-grade materials. “Given the level of safety of these batteries, they could be used in children's toys, where there is a high risk of ingestion,” said Mario Caironi, a senior researcher at IIT. However, this isn’t the only solution the edible battery could provide.

Enlarge / Graduate student W. Walker Smith converted the visible light given off by the elements into audio, creating unique, complex sounds for each one. His personal favorites are helium and zinc. (credit: W. Walker Smith and Alain Barker)

We're all familiar with the elements of the periodic table, but have you ever wondered what hydrogen or zinc, for example, might sound like? W. Walker Smith, now a graduate student at Indiana University, combined his twin passions of chemistry and music to create what he calls a new audio-visual instrument to communicate the concepts of chemical spectroscopy.

Smith presented his data sonification project—which essentially transforms the visible spectra of the elements of the periodic table into sound—at a meeting of the American Chemical Society being held this week in Indianapolis, Indiana. Smith even featured audio clips of some of the elements, along with "compositions" featuring larger molecules, during a performance of his "The Sound of Molecules" show.

As an undergraduate, "I [earned] a dual degree in music composition and chemistry, so I was always looking for a way to turn my chemistry research into music," Smith said during a media briefing . "Eventually, I stumbled across the visible spectra of the elements and I was overwhelmed by how beautiful and different they all look. I thought it would be really cool to turn those visible spectra, those beautiful images, into sound."

Enlarge / Certain squid have the ability to camouflage themselves by making themselves transparent and/or changing their coloration. (credit: YouTube/KQED Deep Look )

Certain cephalopods like cuttlefish, octopuses, and squid have the ability to camouflage themselves by making themselves transparent and/or changing their coloration. Scientists would like to learn more about the precise mechanisms underlying this unique ability, but it's not possible to culture squid skin cells in the lab. Researchers at the University of California, Irvine, have discovered a viable solution: replicating the properties of squid skin cells in mammalian (human) cells in the lab. They presented their research at a meeting of the American Chemical Society being held this week in Indianapolis.

"In general, there's two ways you can achieve transparency," UC Irvine's Alon Gorodetsky, who has been fascinated by squid camouflage for the last decade or so, said during a media briefing at the ACS meeting. "One way is by reducing how much light is absorbed—pigment-based coloration, typically. Another way is by changing how light is scattered, typically by modifying differences in the refractive index." The latter is the focus of his lab's research.

Squid skin is translucent and features an outer layer of pigment cells called chromatophores that control light absorption. Each chromatophore is attached to muscle fibers that line the skin's surface, and those fibers, in turn, are connected to a nerve fiber. It's a simple matter to stimulate those nerves with electrical pulses, causing the muscles to contract. And because the muscles pull in different directions, the cell expands, along with the pigmented areas, which changes the color. When the cell shrinks, so do the pigmented areas.