Enlarge / One of the limestone canopic jars that once held mummified organs of the Egyptian noblewoman Senetnay (c. 1450 BCE). (credit: Museum August Kestner, Hannover/Christian Tepper)

Trying to recreate the scents and smells of the past is a daunting challenge, given the ephemeral nature of these olfactory cues. Now scientists have identified the compounds in the balms used to mummify the organs of an ancient Egyptian noblewoman, according to a recent paper published in the journal Scientific Reports, suggesting that the recipes were unusually complex and used ingredients not native to the region. The authors also partnered with a perfumer to recreate what co-author Barbara Huber calls "the scent of eternity."

“'The scent of eternity’ represents more than just the aroma of the mummification process,” said Huber , an archaeologist at the Max Planck Institute of Geoanthropology in Jena, Germany. “It embodies the rich cultural, historical, and spiritual significance of Ancient Egyptian mortuary practices. Our methods were also able to provide crucial insights into balm ingredients for which there is limited information in contemporary ancient Egyptian textual sources.”

As previously reported , Egyptian embalming is thought to have started in the Predynastic Period or even earlier, when people noticed that the arid heat of the sand tended to dry and preserve bodies buried in the desert. Eventually, the idea of preserving the body after death worked its way into Egyptian religious beliefs. When people began to bury the dead in rock tombs, away from the desiccating sand, they used chemicals like natron salt and plant-based resins for embalming.

Enlarge / Levitation like this will apparently continue to require extremely cold temperatures for now. (credit: ClaudeLux )

The summer of room-temperature superconductivity was short-lived. It started with some manuscripts placed on the arXiv toward the end of July, which purportedly described how to synthesize a compound called LK-99, which would act as a superconductor at temperatures above the boiling point of water. High enough that, if its synthesis and material properties worked out, it could allow us to replace metals with superconductors in a huge range of applications.

Confusion quickly followed, as the nature of the chemical involved made it difficult to know when you were looking at the behavior of LK-99 and when you were looking at related chemicals or even impurities.

But the materials science community responded remarkably quickly. By the end of August, pure samples had been prepared, the role of impurities explored, and a strong consensus had developed: LK-99 was not a superconductor. Best yet, the work nicely provided explanations for why it had behaved a bit like one in a number of situations.

Enlarge / This 1475 letter written by Vlad the Impaler contains proteins suggesting he suffered from respiratory problems, bloodied tears. (credit: Adapted from M.G.G. Pittala et al., 2023/CC BY )

The eponymous villain of Bram Stoker's classic 1897 novel Dracula was partly inspired by a real historical person: Vlad III, a 15th century prince of Wallachia (now southern Romania), known by the moniker Vlad the Impaler because of his preferred method of execution: impaling his victims on spikes. Much of what we know about Vlad III comes from historical documents, but scientists have now applied cutting-edge proteomic analysis to three of the prince's surviving letters, according to a recent paper published in the journal Analytical Chemistry. Among their findings: the Romanian prince was not a vampire, but he may have wept tears of blood, consistent with certain legends about Vlad III.

Vlad III was the second son of Vlad Dracul ("the Dragon"), who became the voivode of Wallachia in 1436. Vlad III was also known as Vlad Dracula ("son of the Dragon"), and it was this name that Stoker used for his fictional vampire— dracul means "the devil" in modern Romanian—along with a few historical details he was able to glean about Wallachia. This was a brutal, bloody period of political instability. Vlad spent several years as a prisoner of the Ottoman Empire, along with his younger brother Radu, and his father and older brother, Mircea, were murdered in 1447. Eventually, Vlad became voivode of Wallachia himself—three times, in fact, interrupted by periods of exile or captivity.

Vlad was constantly at war, and it was his brutal treatment of his enemies that led to his reputation as a monster, particularly in German-speaking territories, where books detailing his atrocities became bestsellers. These accounts described how Vlad executed men, women, and children taken prisoner from a Saxon village and impaled them. The more accurate, eye-witness-based accounts also included details about the churches Vlad's army destroyed during plundering raids in Transylvania. Other stories (many likely exaggerated) claimed he burned the lazy and the poor, and had women impaled along with their nursing babies. A well-known woodcut shows Vlad dining while surrounded by impaled people on poles. He died in battle in January 1477, having killed an estimated 80,000 people in his lifetime.

Enlarge / French physicist Gerard Liger-Belair studied CO₂ levels in 13 old champagne vintages in three different bottle sizes. (credit: Andy Roberts/Getty Images)

A large part of the pleasure of imbibing a glass of champagne comes from its effervescence: all those bubbles rising from the glass and ticking the nose and palate. If there's no fizz, there's no fun—and also less flavor and aromas to savor. A recent paper published in the journal ACS Omega found that the size of the champagne bottle is a key factor in determining when the wine inside will go flat.

As we've reported previously , champagne's effervescence arises from the nucleation of bubbles on the glass walls. Once they detach from their nucleation sites, the bubbles grow as they rise to the liquid surface, where they burst. This typically occurs within a couple of milliseconds, and the distinctive crackling sound is emitted when the bubbles rupture. The bubbles even "ring" at specific resonant frequencies , depending on their size, so it's possible to "hear" the size distribution of bubbles as they rise to the surface in a glass of champagne.

Prior studies have shown that when the bubbles in champagne burst, they produce droplets that release aromatic compounds believed to enhance the flavor. Larger bubbles enhance the release of aerosols into the air above the glass—bubbles on the order of 1.7 mm across at the surface. French physicist Gerard Liger-Belair of the University of Reims Champagne-Ardenne is one of the foremost scientists studying many different aspects of champagne and has now turned his attention to exploring how long champagne can age in the bottle before the carbonation dissipates to the point where those all-important bubbles can no longer form.

Enlarge / Jezero crater shows clear signs of water-formed deposits, so it's not a surprise to find water-altered material there. (credit: NASA/MSSS/USGS )

Organic chemicals, primarily composed of carbon and hydrogen, underly all of life. They're also widespread in the Universe, so they can't be taken as a clear signature of the presence of life. That creates an annoying situation regarding the search for evidence of life on Mars, which clearly has some organic chemicals despite the harsh environment.

But we don't know whether these are the right kinds of molecules to be indications of life. For the moment, we also lack the ability to tear apart Martian rocks, isolate the molecules, and figure out exactly what they are. In the meantime, our best option is to get some rough information on them and figure out the context of where they're found on Mars. And a big step has been made in that direction with the publication of results from imaging done by the Perseverance rover.

Ask SHERLOC

The instrument that's key to the new work has a name that pretty much tells you it was designed to handle this specific question: Scanning Habitable Environments with Raman & Luminescence for Organics & Chemicals (SHERLOC). SHERLOC comes with a deep-UV laser to excite molecules into fluorescing, and the wavelengths they fluoresce at can tell us something about the molecules present. It's also got the hardware to do Raman spectroscopy simultaneously.

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.

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 (credit: mikroman6 / Getty Images )

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.