It’s not easy to extract iron from its ore. But the peoples of the ancient city of Great Zimbabwe—the capital of a thriving kingdom in southern Africa between 1000 to 1700 AD—were masters.

At sites near the city’s stone ruins, clusters of iron-smelting furnaces survive today as mounds of rubble. At Mashava, a village 25 miles northwest, fragments bear fingermarks of those who long ago smoothed the structures’ clay interiors.

Some of the furnaces were nearly an adult’s arm span in width, with walls thick and strong to contain the heat of more than 2,100° Fahrenheit needed to smelt iron. Unlike other furnaces that required workers to force air into them with bellows, these were designed to suck air in, then out through a chimney, no human labor required. This would have made it significantly easier to produce the iron, which was fashioned into hoes, axes, and arrowheads.

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In the Grand Canyon, there is a line in the rock where time seems to have gone missing. Ancient crystalline rocks mark its bottom, while sandstones laid down as life started to diversify during the Cambrian explosion mark the top. “It’s called the Great Unconformity, and it’s a gap in the geologic record,” says Nicolas Flament, a geoscientist at the University of Wollongong, Australia. "This gap can be anywhere between 200 million years, which is not that impressive, to more than a billion years.”

In a recent Nature study, Flament and his colleague Santosh Dhungana argue that this gap was carved with help from deep within the planet. According to their models, slow currents of hot rock in Earth's mantle pushed entire continents up for hundreds of millions of years, letting glaciers grind them down and then let them sink, allowing fresh sediments to bury the scar. The largest hole in the rock record might be a fingerprint of processes happening deep in the planet's interior.

Ice and sea

The oldest sediments resting on the Great Unconformity in North America are between 635 and 482 million years old. Geologists have traced it across most of North America and parts of northern Europe and northern China. “Something seems to have happened, in particular in North America,” Flament says.

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With a huge and still-growing catalog of exoplanets, researchers are eager to take the next steps: trying to infer what conditions are like on them, either by imaging them directly or by capturing the light that has passed through their atmosphere. Both are substantial challenges, given the presence of stars that are far, far brighter than light that has come to us via the planet.

While telescopes can be fitted with devices called coronagraphs that block out much of a star's light, there are limits to their effectiveness, caused by noise from subtle variations in the telescope's configuration and pointing between observations. Now, researchers have developed a new software package that optimizes a physical model of the telescope in a way that allows us to better model these differences, producing low-noise imaging of exoplanets.

Point spreads

Central to this work is the concept of a point spread function. If you use a telescope to image a single point of light, it will not appear that way in the actual image. Instead, it will be slightly blurry and spread out, due to imperfections in the telescope hardware and the limits of our ability to keep it pointed accurately through the time it takes to image something. The mathematical description of how a telescope distorts a point of light is called its point spread function.

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Before Tuesday’s election, Republicans held more governorships and state legislative seats than Democrats, along with an advantage in state trifectas—unified control of the governor’s office and both chambers of the legislature.

That advantage has disappeared, clearing the path for more climate and clean energy legislation, according to analysts and advocates.

Democrats swept the vast majority of competitive races at the state level, flipping control of governors’ offices from Republicans in Georgia, Iowa, Ohio, Nevada, and Texas.

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During World War II, physicists on the Manhattan Project worried that the Nazi German nuclear program might achieve the first nuclear bomb before the US and its allies. That's not what transpired, but historians have debated just how close the Germans came to achieving criticality in their last attempt at building a reactor: the B8 pile. Werner Heisenberg, who led that effort, claimed that they were close and had only needed a little more uranium. But according to a paper published in the Proceedings of the National Academy of Sciences Nexus, that was not the case: The project simply didn't have sufficient uranium and heavy water to build a working bomb, given the design they were using.

This particular research started in 2013, when University of Maryland physicist Timothy Koeth—a co-author on the new paper—received the gift of a mysterious heavy metal cube from a friend. He instantly recognized it as one of the uranium cubes used by German scientists in their unsuccessful attempt to build a working nuclear reactor. Only 14 such cubes are known to exist today.

In 2019, we reported on Koeth’s quest to track down the cube’s origins, as well as several other similar cubes that had somehow found their way across the Atlantic. At the time, Koeth and his partner in the quest, then-graduate student Miriam “Mimi” Hiebert, had tracked down 10 such cubes around the US. For instance, the Smithsonian Institute had a German uranium cube in storage. They tracked a third cube to Harvard University, where it was regularly passed around to students in introductory physics classes as a curiosity.

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It’s a regrettable reality that there is never enough time to cover all the interesting scientific stories we come across. So every month, we highlight a handful of the best stories that nearly slipped through the cracks. October’s list includes an epigenetic mechanism for why large dogs age faster than smaller ones; physicists who trapped a single particle of antimatter for months; and invisible tattoo inks that only show up under UV light.

Why large dogs age faster

In many mammalian species, larger creatures tend to have longer lifespans. Mice, for instance, live an average of just two years, while some whales can last for as long as 200 years. Dogs, however, buck this pattern; larger dogs tend to age faster and die younger than smaller ones, which makes canines an ideal model for biologists to study to learn more about aging in general. Arizona State University scientists report that these lifespan differences seem to be due to so-called "jumping genes," according to a paper published in the journal Science.

The authors used data from 864 dogs collected in the Dog Aging Project to map patterns of DNA methylation (which influences how much certain genes are turned on or off) across the entire genome. It's part of the epigenome, whose markers can change over time in response to stress and other environmental factors. Genetic sequences, by contrast, are largely fixed. So DNA methylation is a good chemical indicator of aging and DNA regulation.

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It's widely acknowledged that it's nearly impossible to publish negative results in scientific journals. "We didn't see anything" is a much harder sell than finding that a hypothesis is clearly right. Findings of no effect tend to either be shuffled off to low-profile journals or left behind as unpublished lab lore.

The high-profile journal Nature, however, made a notable exception this week, publishing a study that tells us that a bunch of methods we have been using to try to measure a key emotional ability don't seem to be measuring the same thing. The results mean that we don't have a good way to measure the impact of a concept that is the basis of a key method in therapy.

Inconsistencies

One of the most successful forms of therapy is cognitive behavioral therapy, or CBT. In part, CBT is based on getting people to step back and engage in "cognitive reappraisal." This requires people to think over a situation that has caused a negative emotional response and find ways to reinterpret it so that it has less impact on them. The ability to engage in this process has been linked to emotional resilience.

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The world is set to miss its 2030 conservation goals as finance and action have fallen short, leaders recognized at a UN biodiversity summit in Armenia’s capital, where they agreed to step up efforts after a final overnight session.

Representatives from almost 200 countries gathered in Yerevan over the past two weeks to review progress on a landmark agreement set four years ago to protect about a third of the world’s land and seas by 2030.

The COP17 talks on biodiversity concluded on Saturday with a recognition that conservation efforts were so far too slow to realistically achieve the goals of the 2022 Kunming-Montreal Global Biodiversity Framework.

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Flying across several time zones often causes jet lag, a feeling where the body insists it's the middle of the night while the clock says it's lunchtime. Now it turns out this nuisance is not exclusive to humans.

A new Science study on Manx shearwaters, seabirds that can fly hundreds of kilometers a day over the North Atlantic, shows they jet-lag themselves during their excursions. And because these birds navigate by the Sun, that jet lag leaves a measurable mark—it skews their compass.

Clockwork compass

Patrick Lewin is a behavioral and sensory ecologist at the University of Oxford and lead author of the study. “Manx shearwaters are medium-sized birds, about the same size as a pigeon,” Lewin said. “They are white underneath and black on top, but they have very long wings, and they are closely related to albatross.” Manx shearwaters nest in burrows on coastal islands around the North Atlantic. Most breed around the UK and Ireland, with about half of their population living in Wales.

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In May 2021, the US Food and Drug Administration released a lengthy briefing document on an experimental medication for a rare autoimmune form of vasculitis that often damages the kidneys and lungs. The agency was on the fence about whether to approve the treatment, and it wanted an independent advisory committee to weigh in. Among the questions at hand: Was the drug meaningfully better than existing therapies?

Participants in the study, which had been conducted by the California biotechnology company ChemoCentryx, did appear to have slightly higher rates of symptom remission after one year. But according to the FDA, it was hard to interpret the results because the study’s design had been less than optimal. Some advisory committee members expressed a similar view. The effect of the drug, said one, “is just not well verified by this study.”

At the same time, many patients, and some physicians, saw in the data a potentially helpful medication, one that might lessen patients’ reliance on steroids, which are highly effective but often cause severe side effects.

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Crater counts tell us that most of the Martian surface is more than 3 billion years old, but pieces of Mars we have on Earth tell a different story. The three main classes of Martian meteorites—shergottites, nakhlites, and chassignites—are all 2.4 billion years old or younger. Until now, only two genuinely ancient Martian meteorites were known: Allan Hills 84001, found in Antarctica, and a jumbled rock from northwest Africa nicknamed Black Beauty. Now we have a third one.

A team led by Yang Liu, a planetary scientist at NASA's Jet Propulsion Laboratory, has shown that a Martian meteorite called Teghaza 001, found in the Sahara Desert in Mali in 2022, formed at least 4.1 billion years ago. “It's very old and similar to some of the oldest rocks on Earth,” Liu says.

A filtered collection

“We don't fully understand why old Martian rocks are so rare on Earth," Liu said. Part of the answer may lie in how a piece of Mars gets here. It takes a large impact to launch a rock off the planet, and not every rock can survive that. “If the impact hits into loose powder, it may not get cemented to become a rock and fly off Mars' gravity,” Liu said. “So the natural impact already acts as a filter. Weak rocks do not make it off Mars.”

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Welcome to Edition 9.17 of the Rocket Report! It's been a while since an American company announced plans for a medium-lift new launch vehicle, but that's what happened this week when a startup named Cowboy Space revealed specs for its Big Iron rocket, named for the classic country-western song by Marty Robbins. I'm a huge fan of the name. Maybe Cowboy Space is striking while the iron is hot as the space industry frets over demand for launch outpacing supply. However, Cowboy Space lags far behind so many other launch providers nearing the launch pad with their medium-class rockets, and the company didn't have much hardware to show at this week's big reveal. In other words, don't mistake style for substance. But we're rocket fans at Ars, and we wish them luck.

As always, we welcome reader submissions, and if you don't want to miss an issue, please subscribe using the box below (the form will not appear on AMP-enabled versions of the site). Each report will include information on small-, medium-, and heavy-lift rockets as well as a quick look ahead at the next three launches on the calendar.

Virgin's new rocket plane reaches home port. The first of Virgin Galactic's new Delta-class rocket planes left its Arizona factory Wednesday for a trip to Spaceport America in neighboring New Mexico, where it will undergo preparations for a test campaign culminating in suborbital flights to the edge of space, Ars reports. Virgin Galactic expects the craft's first commercial spaceflight to take place "early" in the second quarter of 2027, but like every other projected date in aerospace, this should be taken with a grain of salt. Virgin Galactic halted commercial flights of its previous vehicle, VSS Unity, in 2024.

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Rather than directly converting photons into electricity, concentrated solar energy uses mirrors to turn sunlight into heat, which can then be used to drive traditional generating turbines. Up to about a decade ago, there was a case to be made that concentrated solar energy had a bright future, as improvements in heat storage had turned it into a way to generate power around the clock.

It wasn't to be. While concentrated solar costs fell enough to compete with nuclear power, the price of photovoltaics plunged, making solar panels the cheapest source of power in most locations. Currently, if you have a good site to generate solar power, then the economics of PV panels are hard to beat.

That has left us needing to build a mixture of other facilities—typically batteries and natural gas facilities—to handle overnight needs or weather-driven shortfalls. But a small company is promising that it can help avoid the need to build a separate facility. Its version of concentrated solar is designed so that a fossil-fueled backup system shares most of the generating hardware with the solar side.

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United Launch Alliance announced Wednesday it plans to return its Vulcan rocket to service on November 13, nine months after a solid rocket booster anomaly threw the company's 2026 launch schedule into oblivion.

The return-to-flight mission will launch 40 satellites for the Amazon Leo broadband constellation, the first of 38 Vulcan flights Amazon has booked to deploy the bulk of its network. The mission will lift off from Cape Canaveral Space Force Station, Florida, and ULA said the launch date is pending range approval.

The launch is critical for ULA after its new flagship rocket suffered nozzle failures on its solid rocket boosters on two of its first four missions, most recently during a flight in February. In both cases, the rocket overcame the nozzle failure and completed its mission, but officials at the US Space Force, ULA's primary customer, lost confidence in Vulcan.

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The rapid decline of Antarctic sea ice since 2016 has triggered a dramatic shift in a crucial part of Earth’s climate system, scientists say.

In a paper published Wednesday, researchers documented a sharp salinity increase in a vast layer of the Southern Ocean, extending from 2,300 to 4,000 feet deep and encircling Antarctica. The shift reverses decades of freshening and echoes ocean changes usually associated with major global climate shifts over millennia but is now happening in just a few years.

The switch from a decades-long trend of freshening water to increasing salinity has implications that could extend beyond Antarctica. The layer, known as Antarctic Intermediate Water, spreads northward into the Indian, Pacific, and Atlantic oceans, transporting heat, carbon, oxygen, and nutrients toward the tropics, and even across the equator, said co-author Bishakhdatta Gayen, a researcher and professor at the University of Melbourne and at the Centre for Atmospheric and Oceanic Sciences in Bengaluru, India.

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Protein design tools may be getting increasingly sophisticated, but you still need a sophisticated understanding of protein structure for them to work. This can include knowing enzyme mechanisms down to the positions of specific amino acids, as well as the water molecules that also occupy the area where catalysis takes place. Once you specify these, the tools can build the rest of a protein around this target.

A large collaboration of researchers based in China, however, decided to bring protein design to the masses, making a tool that can take natural language prompts and use them to produce proteins with the function you specify. If your measure for success is a working protein, then the success rate may not be great. But they still manage to get the job done. And, in a separate announcement, Hugging Face shared that it's now hosting a tool that does similar things on the DNA level.

The equivalent of vibe coding may have come to protein design—at least if you have access to a lab where you can sort the good designs from the dozens of failed ones.

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Dating back to around 400 CE and made of dichroic glass, the Lycurgus Cup is notable for exhibiting different colors depending on the light. (It gets its name from the scene depicted on its surface, of King Lycurgus of Thrace.) Light it from the front, and the cup looks green; light it from behind, and the color changes to a deep red. University of Sheffield scientists have re-created the original recipe to produce a contemporary glass sculpture with the same optical effect.

The cup is considered one of the seven glass wonders of the world, one of just 40 glass cage cups that survived. Exactly why the unusual color effects of the Lycurgus Cup occurred was a mystery until 2007, when a team of scientists discovered the color shifts were due to the presence of nanoparticles in the glass—the result of Roman artisans adding finely ground gold and silver into the mix. Those nanoparticles change how the electrons in the cup vibrate in response to light so that the color one sees shifts with the observer’s vantage point.

As we reported in 2019, it’s a similar phenomenon to the one responsible for the shifting colors of 19th-century daguerreotypes due to the scattering properties of nanoparticles. The Romans added salt when they melted the silicon (sand) to make the glass, and those salts contained gold atoms. In the melting process, those atoms aggregate and produce nanoparticles, which in turn produce the colors. It’s how any stained glass is made. It's also similar to how the precise lattice-like structure of photonic crystals produces iridescent colors in nature, like the wings of butterflies, or opals.

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Sir Arthur Conan Doyle created one of the most beloved fictional detectives of all time in Sherlock Holmes, spawning countless novels, films, TV series, and so forth featuring the sleuth. Far fewer people know about the real-life inspiration for Holmes: a renowned surgeon at Scotland's University of Edinburgh named Joseph Bell, who taught Doyle when the author was still a young medical student. Bell is the subject of a new, eminently readable biography, Sleuth-Hound: The Case of the Real Sherlock Holmes, by medical historian Lindsey Fitzharris.

A noted science communicator with a fondness for the medically macabre, Fitzharris published a biography of Scottish surgical pioneer Joseph Lister, The Butchering Art, in 2017—a great, if occasionally grisly, read. She followed up with 2022’s  The Facemaker: A Visionary Surgeon’s Battle to Mend the Disfigured Soldiers of World War I, about a WWI surgeon named Harold Gillies who rebuilt the faces of injured soldiers.

In 2020, Fitzharris hosted a documentary for the Smithsonian Channel, The Curious Life and Death Of…, exploring famous deaths, ranging from drug lord Pablo Escobar to magician Harry Houdini. Fitzharris performed virtual autopsies, experimented with blood samples, interviewed witnesses, and conducted real-time demonstrations in hopes of gleaning fresh insights. And last year she and her husband, caricaturist Adrian Teal, collaborated on an illustrated children's book, Dead Ends! Flukes, Flops, and Failures that Sparked Medical Marvels.

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Every morning during the Martian spring and summer, a thin and extremely long cloud emerges, only to disappear again. The wispy formation appears near the volcano Arsia Mons and gradually elongates until it reaches over 1,000 miles—about the distance from New York to Kansas City as the crow flies—before dissipating. This cycle then repeats for several months.

Since it was first recorded by a probe in 2018, scientists have been unable to find a plausible explanation for the existence of this cloud, often referred to as the Arsia Mons Elongated Cloud (AMEC). Until now. Recently, researchers successfully modeled the cloud’s formation for the first time, their results suggesting that it may be driven by a physical process that has never been directly observed in any planet's atmosphere.

"We found that we needed to include some exotic physics… physics that, while included in textbooks, is treated as theoretical and usually thought not to happen in nature. It certainly hasn’t been seen in action before," Jorge Hernández-Bernal, a planetary scientist at Paris’ Sorbonne Université and lead author of the study, said in a press release. "Once we included this physics in our simulations, the AMEC emerged just as we hoped.”

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Barnes Ice Cap sits on the central plateau of Baffin Island, in the Canadian Arctic. It is the last surviving fragment of the Laurentide Ice Sheet, the largest of the Pleistocene ice sheets, which at its peak buried most of Canada under two miles of ice and locked away around 80 meters of sea level. That remnant has now yielded direct physical evidence that ice sheets might have reversed their retreat and started to grow again thousands of years ago.

In a recent Science study, researchers show that the Laurentide reached its smallest size about 3,600 years ago, then started re-expanding roughly 2,000 years ago, which the team interprets as the opening move of the next glaciation. Apparently, this brand-new ice age was on its way until about 1960, when human-caused climate warming reversed it.

Frozen to the bed

“Barnes is the last remaining piece of one of the domes of the Laurentide Ice Sheet,” says Nicolás Young, a geologist at Columbia University's Lamont-Doherty Earth Observatory and lead author of the study. As that enormous dome thinned through the Holocene, its margin withdrew up onto Baffin Island, and what's left today is the deflated core of something that was once two miles thick. The reason Barnes can testify about its own history, Young explains, comes down to the temperature at its base.

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