Last year, researchers sequenced the genome of famed composer Ludwig van Beethoven for the first time, based on authenticated locks of hair. The same team has now analyzed two of the locks for toxic substances and found extremely high levels of lead, as well as arsenic and mercury, according to a recent letter published in the journal Clinical Chemistry.

“It definitely shows Beethoven was exposed to high concentrations of lead,” Paul Janetto, co-author and director of the Mayo Clinic's Department of Laboratory Medicine and Pathology, told The New York Times. “These are the highest values in hair I’ve ever seen. We get samples from around the world, and these values are an order of magnitude higher.” That said, the authors concluded that the lead exposure was not sufficient to actually kill the composer, although Beethoven very likely did suffer adverse health effects because of it.

As previously reported, Beethoven was plagued throughout his life by myriad health problems. The composer began losing his hearing in his mid- to late 20s, experiencing tinnitus and the loss of high-tone frequencies in particular. He claimed the onset began with a fit in 1798 induced by a quarrel with a singer. By his mid-40s, he was functionally deaf and unable to perform public concerts, although he could still compose music.

Beethoven also had lifelong chronic gastric ailments, including persistent abdominal pains and prolonged stretches of diarrhea. By 1821, the composer showed signs of liver disease, marked by the first of two severe attacks of jaundice. These issues certainly affected his career and emotional state, so much so that Beethoven requested—via a letter addressed to his brothers—that his favorite physician examine his body after his death to determine the cause of all his suffering.

By December 1826, Beethoven was quite ill, suffering from a second bout of jaundice and swollen limbs, fever, dropsy, and labored breathing. His doctor performed several operations to remove excess fluid from the composer's abdomen. On March 24, 1827, he purportedly said to visitors, "Plaudite, amici, comoedia finita est" ("Applaud, friends, the comedy is over"). Two days later, he died. According to his good friend Anselm Hüttenbrenner, who was present, lightning and a loud clap of thunder briefly woke Beethoven, who "opened his eyes, lifted his right hand and looked up for several seconds with his fist clenched... not another breath, not a heartbeat more."

An autopsy identified severe liver damage (evidence of cirrhosis) as the likely cause of death and significant dilation of the auditory nerve. But what caused that liver damage or his hearing loss—or his chronic stomach complaints, for that matter? Medical detectives have been debating possible causes for nearly two centuries, drawing on the composer's letters, diaries, and physicians' notes for evidence, as well as reports on skeletal remains from when his body was exhumed in 1863 and 1888. But no general consensus emerged.

Last year, scientists successfully sequenced Beethoven's genome based on samples taken from five authenticated preserved locks of hair. While the analysis of that genome failed to pinpoint a definitive cause of Beethoven's hearing loss or chronic digestive problems, he did have numerous risk factors for liver disease and was infected with hepatitis B. The researchers also found genetic evidence that somewhere in the Beethoven paternal line, an ancestor had an extramarital affair.

Past scholars have attributed the hearing loss to otosclerosis, or possibly lead poisoning from the wines Beethoven preferred. The composer's contemporaries thought his alcohol consumption was moderate, although standards were different in the early 19th century, and his own "conversation books" show he was a regular drinker. He may have been drinking as much as a liter a day around 1825–1826, and there does seem to be a family history of alcohol dependence and liver disease. Plus the wine in Beethoven's time often contained lead sugar (lead acetate), with the corks often being pre-soaked in lead salt to get a better seal. Alternatively, it could have been due to complications from when he contracted murine typhus in 1796.

Toxicological analysis of hair samples claimed to be those of Beethoven had been done in the past, along with an examination of skull fragments. But the lead poisoning argument rested largely on a lock of hair (the Hiller lock) that the 2023 analysis showed was not authentic and actually belonged to a woman. So the same team decided to perform toxicological testing on two of the authenticated five locks using mass spectroscopy—the Bermann lock and the Halm-Thayer lock. The Hall-Thayer lock was particularly of interest because it's the only one known to have come from Beethoven himself; the composer hand-delivered it to his friend, pianist Anton Hall, in April 1826.

The team found that the Bermann lock had very high levels of lead—64 times higher than the upper limit of what is considered typical in a healthy person—while the Hall-Thayer lock had lead levels 95 times higher. That means the amount of lead in Beethoven's blood could have been between 69 and 71 micrograms per deciliter. "Such lead levels are commonly associated with gastrointestinal and renal ailments and decreased hearing but are not considered high enough to be the sole cause of death," the authors wrote.

The authors acknowledged certain limitations to their analysis. For instance, hair samples can be contaminated by environmental lead as well as contaminants in artificial hair treatments like dyes. However, there is no evidence that Beethoven ever used such treatments, and the study protocols removed any external contaminants prior to testing. It's also true that high lead levels in hair may not be a good predictor of levels in the blood, although the authors note prior research showing a correlation between high lead hair levels and kidney and liver disease.

"While the concentrations determined are not supportive of the notion that lead exposure caused Beethoven's death, it may have contributed to the documented ailments that plagued him most of his life," the authors concluded. "We believe this is an important piece of a complex puzzle and will enable historians, physicians, and scientists to better understand the medical history of the great composer."

Clinical Chemistry, 2024. DOI: 10.1093/clinchem/hvae054  (About DOIs).

After a night of stunning auroras across much of the United States and Europe on Friday, a severe geomagnetic storm is likely to continue through at least Sunday, forecasters said.

The Space Weather Prediction Center at the US-based National Oceanic and Atmospheric Prediction Center observed that 'Extreme' G5 conditions were ongoing as of Saturday morning due to heightened Solar activity.

"The threat of additional strong flares and CMEs (coronal mass ejections) will remain until the large and magnetically complex sunspot cluster rotates out of view over the next several days," the agency posted in an update on the social media site X on Saturday morning.

Good and bad effects

For many observers on Friday night the heightened Solar activity was welcomed. Large areas of the United States, Europe, and other locations unaccustomed to displays of the aurora borealis saw vivid lights as energetically charged particles from the Solar storm passed through the Earth's atmosphere. Brilliantly pink skies were observed as far south as Texas. Given the forecast for ongoing Solar activity, another night of extended northern lights is possible again on Saturday.

There were also some harmful effects. According to NOAA, there have been some irregularities in power grid transmissions, and degraded satellite communications and GPS services. Users of SpaceX's Starlink satellite internet constellation have reported slower download speeds. Early on Saturday morning, SpaceX founder Elon Musk said the company's Starlink satellites were "under a lot of pressure, but holding up so far."

This is the most intense Solar storm recorded in more than two decades. The last G5 event—the most extreme category of such storms—occurred in October 2003 when there were electricity issues reported in Sweden and South Africa.

Should this storm intensify over the next day or two, scientists say the major risks include more widespread power blackouts, disabled satellites, and long-term damage of GPS networks.

Cause of these storms

Such storms are triggered when the Sun ejects a significant amount of its magnetic field and plasma into the Solar wind. The underlying causes of these coronal mass ejections, deeper in the Sun, are not fully understood. But it is hoped that data collected by NASA's Parker Solar Probe and other observations will help scientists better understand and predict such phenomena.

When these coronal mass ejections reach Earth's magnetic field they change it, and can introduce significant currents into electricity lines and transformers, leading to damages or outages.

The most intense geomagnetic storm occurred in 1859, during the so-called Carrington Event. This produced auroral lights around the world, and caused fires in multiple telegraph stations—at the time there were 125,000 miles of telegraph lines in the world.

According to one research paper on the Carrington Event, "At its height, the aurora was described as a blood or deep crimson red that was so bright that one 'could read a newspaper by'."

Our Moon may appear to shine peacefully in the night sky, but billions of years ago, it was given a facial by volcanic turmoil.

One question that has gone unanswered for decades is why there are more titanium-rich volcanic rocks, such as ilmenite, on the near side as opposed to the far side. Now a team of researchers at Arizona Lunar and Planetary Laboratory are proposing a possible explanation for that.

The lunar surface was once flooded by a bubbling magma ocean, and after the magma ocean had hardened, there was an enormous impact on the far side. Heat from this impact spread to the near side and made the crust unstable, causing sheets of heavier and denser minerals on the surface to gradually sink deep into the mantle. These melted again and were belched out by volcanoes. Lava from these eruptions (more of which happened on the near side) ended up in what are now titanium-rich flows of volcanic rock. In other words, the Moon’s old face vanished, only to resurface.

What lies beneath

The region of the Moon in question is known as the Procellarum KREEP Terrane (PKT). KREEP signifies high concentrations of potassium (K), rare earth elements (REE), and phosphorus (P). This is also where ilmenite-rich basalts are found. Both KREEP and the basalts are thought to have first formed when the Moon was cooling from its magma ocean phase. But the region stayed hot, as KREEP also contains high levels of radioactive uranium and thorium.

“The PKT region… represents the most volcanically active region on the Moon as a natural result of the high abundances of heat-producing elements,” the researchers said in a study recently published in Nature Geoscience.

Why is this region located on the near side, while the far side is lacking in KREEP and ilmenite-rich basalts? There was one existing hypothesis that caught the researchers’ attention: it proposed that after the magma ocean hardened on the near side, sheets of these KREEP minerals were too heavy to stay on the surface. They began to sink into the mantle and down to the border between the mantle and core. As they sank, these mineral sheets were thought to have left behind trace amounts of material throughout the mantle.

If the hypothesis was accurate, this would mean there should be traces of minerals from the hardened KREEP magma crust in sheet-like configurations beneath the lunar surface, which could reach all the way down to the edge of the core-mantle boundary.

How could that be tested? Gravity data from the GRAIL (Gravity Recovery and Interior Laboratory) mission to the Moon possibly had the answer. It would allow them to detect gravitational anomalies caused by the higher density of the KREEP rock compared to surrounding materials.

Coming to the surface

GRAIL data had previously revealed that there was a pattern of subsurface gravitational anomalies in the PKT region. This appeared similar to the pattern that the sheets of volcanic rock were predicted to have made as they sank, which is why the research team decided to run a computer simulation of sinking KREEP to see how well the hypothesis matched up with the GRAIL findings.

Sure enough, the simulation ended up forming just about the same pattern as the anomalies GRAIL found. The polygonal pattern seen in both the simulations and GRAIL data most likely means that traces of heavier KREEP and ilmenite-rich basalt layers were left behind beneath the surface as those layers sank due to their density, and GRAIL detected their residue due to their greater gravitational pull. GRAIL also suggested there were many lesser anomalies in the PKT region, which makes sense considering that a large part of the crust is made of volcanic rocks thought to have sunk and left behind residue before they melted and surfaced again through eruptions.

We now also have an idea of when this phenomenon occurred. Because there are impact basins that dated to around 4.22 billion years ago (not to be confused with the earlier far-side impact), but the magma ocean is thought to have hardened before that, the researchers think that the crust also began to sink before that time.

“The PKT border anomalies provide the most direct physical evidence for the nature of the post-magma ocean… mantle overturn and sinking of ilmenite into the deep interior,” the team said in the same study.

This is just one more bit of information regarding how the Moon evolved and why it is so uneven. The near side once raged with lava that is now volcanic rock, much of which exists in flows called mare (which translates to “sea” in Latin). Most of this volcanic rock, especially in the PKT region, contains rare earth elements.

We can only confirm that there really are traces of ancient crust inside the Moon by the collection of actual lunar material far beneath the surface. When Artemis astronauts are finally able to gather samples of volcanic material from the Moon in situ, who knows what will come to the surface?

Nature Geoscience, 2024.  DOI: 10.1038/s41561-024-01408-2

Diehard fans of cold-brew coffee put in a lot of time and effort for their preferred caffeinated beverage. But engineers at the University of New South Wales, Sydney, figured out a nifty hack. They rejiggered an existing espresso machine to accommodate an ultrasonic transducer to administer ultrasonic pulses, thereby reducing the brewing time from 12 to 24 hours to just under three minutes, according to a new paper published in the journal Ultrasonics Sonochemistry.

As previously reported, rather than pouring boiling or near-boiling water over coffee grounds and steeping for a few minutes, the cold-brew method involves mixing coffee grounds with room-temperature water and letting the mixture steep for anywhere from several hours to two days. Then it is strained through a sieve to filter out all the sludge-like solids, followed by filtering. This can be done at home in a Mason jar, or you can get fancy and use a French press or a more elaborate Toddy system. It's not necessarily served cold (although it can be)—just brewed cold.

The result is coffee that tastes less bitter than traditionally brewed coffee. “There’s nothing like it,” co-author Francisco Trujillo of UNSW Sydney told New Scientist. “The flavor is nice, the aroma is nice and the mouthfeel is more viscous and there’s less bitterness than a regular espresso shot. And it has a level of acidity that people seem to like. It’s now my favorite way to drink coffee.”

While there have been plenty of scientific studies delving into the chemistry of coffee, only a handful have focused specifically on cold-brew coffee. For instance, a 2018 study by scientists at Thomas Jefferson University in Philadelphia involved measuring levels of acidity and antioxidants in batches of cold- and hot-brew coffee. But those experiments only used lightly roasted coffee beans. The degree of roasting (temperature) makes a significant difference when it comes to hot-brew coffee. Might the same be true for cold-brew coffee?

To find out, the same team decided in 2020 to explore the extraction yields of light-, medium-, and dark-roast coffee beans during the cold-brew process. They used the cold-brew recipe from The New York Times for their experiments, with a water-to-coffee ratio of 10:1 for both cold- and hot-brew batches. (Hot brew normally has a water-to-coffee ratio of 20:1, but the team wanted to control variables as much as possible.) They carefully controlled when water was added to the coffee grounds, how long to shake (or stir) the solution, and how best to press the cold-brew coffee.

The team found that for the lighter roasts, caffeine content and antioxidant levels were roughly the same in both the hot- and cold-brew batches. However, there were significant differences between the two methods when medium- and dark-roast coffee beans were used. Specifically, the hot-brew method extracts more antioxidants from the grind; the darker the bean, the greater the difference. Both hot- and cold-brew batches become less acidic the darker the roast.

That gives cold brew fans a few handy tips, but the process remains incredibly time-consuming; only true aficionados have the patience required to cold brew their own morning cuppa. Many coffee houses now offer cold brews, but it requires expensive, large semi-industrial brewing units and a good deal of refrigeration space. According to Trujillo, the inspiration for using ultrasound to speed up the process arose from failed research attempts to extract more antioxidants. Those experiments ultimately failed, but the setup produced very good coffee.

Trujillo et al. used a Breville Dual Boiler BES920 espresso machine for their latest experiments, with a few key modifications. They connected a bolt-clawed transducer to the brewing basket with a metal horn. They then used the transducer to inject 38.8 kHz sound waves through the walls at several different points, thereby transforming the filter basket into a powerful ultrasonic reactor.

The team used the machine's original boiler but set it up to be independently controlled it with an integrated circuit to better manage the temperature of the water. As for the coffee beans, they picked Campos Coffee's Caramel & Rich Blend (a medium roast). "This blend combines fresh, high-quality specialty coffee beans from Ethiopia, Kenya, and Colombia, and the roasted beans deliver sweet caramel, butterscotch, and milk chocolate flavors," the authors wrote.

There were three types of samples for the experiments: cold brew hit with ultrasound at room temperature for one minute or for three minutes, and cold brew prepared with the usual 24-hour process. For the ultrasonic brews, the beans were ground into a fine grind typical for espresso, while a slightly coarser grind was used for the traditional cold-brew coffee.

The results: making cold-brew coffee with ultrasound doubled the extraction yield and caffeine concentration compared to samples that weren't zapped with ultrasound, thanks to more efficient extraction of the oils, flavors, and aroma of the ground coffee. They also found a strong correlation between how fully one filled the brewing basket with coffee grounds (the grounds for cold brew aren't tamped down) and the quantity of extracted components and the physical properties of the brew. A cold brew espresso shot made with the ultrasonic method was a different color than regularly prepared cold brew because the sound waves serve to emulsify the oils in the coffee.

“Ultrasounds accelerate the extraction process due to acoustic cavitation,” said Trujillo. “When acoustic bubbles collapse near the grounded coffee, they generate micro-jets with enough force to pit and fracture the coffee grounds—intensifying the extraction of the aroma and flavors of the brew. And the acceleration is enormous—we are reducing what would typically take 12 to 24 hours to less than three minutes.” That's definitely a potential boon for coffee shops eager to make cold brew coffee on demand.

But what about the flavor? For the sensory part of the study, Trujillo et al. recruited a panel of 11 trained sensory evaluators via the Queensland Alliance for Agriculture and Food Innovation to taste the various samples and rate them according to a range of sensory properties. These included aroma (intensity, fruity, cream, dark caramel, dark chocolate, nutty, ashy); the fullness of the texture; and flavor (intensity, sourness, saltiness, sweetness, bitterness, ashy); and aftertaste (sourness, bitterness, ashy, and astringency).

The tasters scored the one-minute cold brews similarly to 24-hour brews in terms of flavor and aftertaste, but they scored it lower on aroma intensity and the dark chocolate notes. Per Trujillo, this means the one-minute brews were slightly under-extracted. In the case of the three-minute brews, the dark chocolate aroma and aroma intensity were comparable to the 24-hour brews, but they were more bitter, suggesting the brew was over-extracted. The authors concluded that the ideal ultrasonic brewing time is somewhere between one and three minutes. They hope to perform more experiments using different types of beans from different regions.

DOI: Ultrasonics Sonochemistry, 2024. 10.1016/j.ultsonch.2024.106885  (About DOIs).

Brewing cold brew coffee in under three minutes with ultrasound.

It is becoming increasingly accepted that classic psychedelics like LSD, psilocybin, ayahuasca, and mescaline can act as antidepressants and anti-anxiety treatments in addition to causing hallucinations. They act by binding to a serotonin receptor. But there are 14 known types of serotonin receptors, and most of the research into these compounds has focused on only one of them—the one these molecules like, called 5-HT2A. (5-HT, short for 5-hydroxytryptamine, is the chemical name for serotonin.)

The Colorado River toad (Incilius alvarius), also known as the Sonoran Desert toad, secretes a psychedelic compound that likes to bind to a different serotonin receptor subtype called 5-HT1A. And that difference may be the key to developing an entirely distinct class of antidepressants.

Uncovering novel biology

Like other psychedelics, the one the toad produces decreases depression and anxiety and induces meaningful and spiritually significant experiences. It has been used clinically to treat vets with post-traumatic stress disorder and is being developed as a treatment for other neurological disorders and drug abuse. 5-HT1A is a validated therapeutic target, as approved drugs, including the antidepressant Viibryd and the anti-anxiety med Buspar, bind to it. But little is known about how psychedelics engage with this receptor and which effects it mediates, so Daniel Wacker’s lab decided to look into it.

The researchers started by making chemical modifications to the frog psychedelic and noting how each of the tweaked molecules bound to both 5-HT2A  and 5-HT1A. As a group, these psychedelics are known as “designer tryptamines”—that’s tryp with a “y”, mind you—because they are metabolites of the amino acid tryptophan.

The lab made 10 variants and found one that is more than 800-fold selective about sticking to 5-HT1A as compared to 5-HT2A. That makes it a great research tool for elucidating the structure-activity relationship of the 5-HT1A receptor, as well as the molecular mechanisms behind the pharmacology of the drugs on the market that bind to it. The lab used it to explore both of those avenues. However, the variant's ultimate utility might be as a new therapeutic for psychiatric disorders, so they tested it in mice.

Improving the lives of mice

The compound did not induce hallucinations in mice, as measured by the “head-twitch response.” But it did alleviate depression, as measured by a “chronic social defeat stress model.” In this model, for 10 days in a row, the experimental mouse was introduced to an “aggressor mouse” for “10-minute defeat bouts”; essentially, it got beat up by a bully at recess for two weeks. Understandably, after this experience, the experimental mouse tended not to be that friendly with new mice, as controls usually are. But when injected with the modified toad psychedelic, the bullied mice were more likely to interact positively with new mice they met.

Depressed mice, like depressed people, also suffer from anhedonia: a reduced ability to experience pleasure. In mice, this manifests in not taking advantage of drinking sugar water when given the opportunity. But treated bullied mice regained their preference for the sweet drink. About a third of mice seem to be “stress-resilient” in this model; the bullying doesn’t seem to phase them. The drug increased the number of resilient mice.

The 5-HT2A receptor has hogged all of the research love because it mediates the hallucinogenic effects of many popular psychedelics, so people assumed that it must mediate their therapeutic effects, too. However, Wacker argues that there is little evidence supporting this assumption. Wacker’s new toad-based psychedelic variant and its preference for the 5-HT1A receptor will help elucidate the complementary roles these two receptor subtypes play in mediating the cellular and psychological effects of psychedelic molecules. And it might provide the basis for a new tryptamine-based mental health treatment as well—one without hallucinatory side effects, disappointing as that may be to some.

Nature, 2024.  DOI: 10.1038/s41586-024-07403-2

If you puncture the ovary of a wasp called Microplitis demolitor, viruses squirt out in vast quantities, shimmering like iridescent blue toothpaste. “It’s very beautiful, and just amazing that there’s so much virus made in there,” says Gaelen Burke, an entomologist at the University of Georgia.

M. demolitor  is a parasite that lays its eggs in caterpillars, and the particles in its ovaries are “domesticated” viruses that have been tuned to persist harmlessly in wasps and serve their purposes. The virus particles are injected into the caterpillar through the wasp’s stinger, along with the wasp’s own eggs. The viruses then dump their contents into the caterpillar’s cells, delivering genes that are unlike those in a normal virus. Those genes suppress the caterpillar’s immune system and control its development, turning it into a harmless nursery for the wasp’s young.

The insect world is full of species of parasitic wasps that spend their infancy eating other insects alive. And for reasons that scientists don’t fully understand, they have repeatedly adopted and tamed wild, disease-causing viruses and turned them into biological weapons. Half a dozen examples already are described, and new research hints at many more.

By studying viruses at different stages of domestication, researchers today are untangling how the process unfolds.

Partners in diversification

The quintessential example of a wasp-domesticated virus involves a group called the bracoviruses, which are thought to be descended from a virus that infected a wasp, or its caterpillar host, about 100 million years ago. That ancient virus spliced its DNA into the genome of the wasp. From then on, it was part of the wasp, passed on to each new generation.

Over time, the wasps diversified into new species, and their viruses diversified with them. Bracoviruses are now found in some 50,000 wasp species, including M. demolitor. Other domesticated viruses are descended from different wild viruses that entered wasp genomes at various times.

Researchers debate whether domesticated viruses should be called viruses at all. “Some people say that it’s definitely still a virus; others say it’s integrated, and so it’s a part of the wasp,” says Marcel Dicke, an ecologist at Wageningen University in the Netherlands who described how domesticated viruses indirectly affect plants and other organisms in a 2020 paper in the Annual Review of Entomology.

As the wasp-virus composite evolves, the virus genome becomes scattered through the wasp’s DNA. Some genes decay, but a core set is preserved—those essential for making the original virus’s infectious particles. “The parts are all in these different locations in the wasp genome. But they still can talk to each other. And they still make products that cooperate with each other to make virus particles,” says Michael Strand, an entomologist at the University of Georgia. But instead of containing a complete viral genome, as a wild virus would, domesticated virus particles serve as delivery vehicles for the wasp’s weapons.

Those weapons vary widely. Some are proteins, while others are genes on short segments of DNA. Most bear little resemblance to anything found in wasps or viruses, so it’s unclear where they originated. And they are constantly changing, locked in evolutionary arms races with the defenses of the caterpillars or other hosts.

In many cases, researchers have yet to discover even what the genes and proteins do inside the wasps’ hosts or prove that they function as weapons. But they have untangled some details.

For example, M. demolitor  wasps use bracoviruses to deliver a gene called glc1.8  into the immune cells of moth caterpillars. The glc1.8  gene causes the infected immune cells to produce mucus that prevents them from sticking to the wasp’s eggs. Other genes in M. demolitor’s bracoviruses force immune cells to kill themselves, while still others prevent caterpillars from smothering parasites in sheaths of melanin.

The wasps keep control

Virus-taming is likely a dangerous endeavor. After all, the wild relatives of domesticated viruses can be deadly, commandeering cells to produce viral particles and then to burst, releasing their contents. Some of them make the innards of insects dissolve into goop. In fact, even in the domesticated situation, sometimes specialized cells in wasp ovaries must burst in order to release viral particles.

“The wasp has to find a way to control that virus so that it’s not infecting and killing the wasp itself,” says Kelsey Coffman, an entomologist at the University of Tennessee.

Cotesia glomerata wasps lay their eggs in white butterfly caterpillars, along with bracovirus particles. The

bracoviruses infect the caterpillars’ cells and ensure that the caterpillar’s body does not harm the developing

wasps. When the wasp larvae are ready, they crawl out of the caterpillar and pupate. The caterpillar spins a

protective webbing over the wasp pupae and defends them until they emerge as adults. The viruses remain

in the caterpillar’s cells after the wasp larvae have emerged, so some researchers speculate that they might

be responsible for the caterpillars’ protective behavior.

How have wasps evolved to control their pet viruses? Most important, they’ve neutered them. The virus particles can’t reproduce because they don’t contain the genes that are crucial to building new virus particles. Those remain in the wasp genome.

Wasps also control where and when the domesticated virus particles are produced, presumably to reduce the risk of the virus going rogue. Bracovirus particles are made only in one pocket of the female’s reproductive tract, and only for a limited time.

And key virus genes have been lost altogether such that the domesticated viruses cannot replicate their own DNA. This loss is seen even in recently domesticated viruses, suggesting that it’s an important first step.

In fact, any viral genes that don’t help the wasp will gradually accumulate mutations. In bracoviruses, so much time has passed that the unused genes are unrecognizable. In viruses domesticated more recently, the remnants can still be identified.

A “missing link” revealed

There’s nothing special about having a genome full of dead viruses. Viruses jump into animal genomes all the time; even our own DNA is littered with their remains. But only parasitic wasps are known to maintain whole sets of genes that still work together to build viral particles.

Researchers are eager to understand how these relationships start. For clues, some are turning to a little orange wasp called Diachasmimorpha longicaudata, which may be in the early stages of domesticating a poxvirus. The poxvirus is not a true domesticated virus because its DNA hasn’t entered the wasp’s genome. Instead, it replicates on its own in the wasp’s venom glands.

Like other virus-taming wasps, D. longicaudata injects viral particles into its host, which in this case is a fruit fly maggot. And Coffman and Burke, with researcher Taylor Harrell, have shown that without the poxvirus, most of the wasp larvae die. But unlike fully domesticated viruses, the poxvirus also replicates outside the wasp, producing new virus particles in the maggot’s cells. The wasp benefits from the poxvirus, but she doesn’t fully control it.

This weak control could reflect the type of virus the wasps started with, says Coffman. Most domesticated viruses are descended from types of viruses called nudiviruses, which can integrate into wasp genomes more easily than poxviruses.

But it’s also possible the wasps just haven’t had enough time yet. Indeed, the wasp-poxvirus partnership is so new it appears to be present in only one species of wasp. It’s even missing from another species that is so similar that Coffman didn’t at first realize she had both wasps in her lab.

Still, the virus is isolated to certain tissues and only replicates when eggs are developing, which could mean that D. longicaudata has already established some defenses. The viruses also seem to be losing their ability to be transmitted without the wasp’s help. “I’ve tried feeding the flies with a lot of virus and they don’t seem to get infected that way,” Coffman says.

The poxvirus system is exciting, adds Coffman, because so little is known about how virus domestication begins. “We can’t go back in time and know how it started. But with this system—it’s new. We’ve got this snapshot of, you could say, the missing link.”

Though no one knows for sure why virus domestication keeps happening in parasitic wasps, researchers suspect it’s related to their lifestyle. Internal parasites live in their hosts’ innards, hazardous environments that are actively trying to kill them. From a wasp’s perspective, viruses are like packages loaded with tools for solving this most dire problem.

Support for this idea comes from 2023 research looking at the genomes of more than 120 species of wasps, ants, and bees. The researchers scoured these genomes for signs of the types of viruses that tend to become domesticated. They inferred the presence of domesticated viruses by detecting virus genes that have been kept in a functional state over evolutionary time. Such preservation would not be expected unless the genes were helping the wasps to survive or reproduce.

As expected, non-parasitic insects showed little evidence of having these domesticated viruses. The same was true of parasites that develop on the outsides of their hosts’ bodies, where the host immune system can’t get at them. But in the parasites that develop inside other insects—called endoparasitoids—domesticated viruses appeared to be far more common.

“There is a special connection between viruses and these endoparasitoids,” says Julien Varaldi, an evolutionary biologist at Claude Bernard University Lyon 1 in France and one of the study’s authors. “It’s suggesting that those viruses do play an important role in the evolution of this way of life.”

And with hundreds of thousands of wasp species and uncountable strains of viruses, there are ample chances for the two entities to team up. It is, Strand says, “an evolutionary sandbox of opportunity.”

Nala Rogers is a science journalist and a champion of underappreciated organisms. Her work has appeared in outlets such as Science, Nature, Popular Mechanics, Discover, and Scientific American. You can read more of it at https://authory.com/nalarogers.

This story originally appeared in Knowable Magazine.

Knowable Magazine, 2024. DOI:10.1146/knowable-050724-2 (About DOIs)

In 2005, the United States Congress laid out a clear mandate: To protect our civilization and perhaps our very species, by 2020, the nation should be able to detect, track, catalog, and characterize no less than 90 percent of all near-Earth objects at least 140 meters across.

As of today, four years after that deadline, we have identified less than half and characterized only a small percentage of those possible threats. Even if we did have a full census of all threatening space rocks, we do not have the capabilities to rapidly respond to an Earth-intersecting asteroid (despite the success of NASA’s Double-Asteroid Redirection Test (DART) mission).

Some day in the finite future, an object will pose a threat to us—it’s an inevitability of life in our Solar System. The good news is that it’s not too late to do something about it. But it will take some work.

Close encounters

The dangers are, to put it bluntly, everywhere around us. The International Astronomical Union’s Minor Planet Center, which maintains a list of (no points award for guessing correctly) minor planets within the Solar System, has a running tally. At the time of the writing of this article, the Center has recorded 34,152 asteroids with orbits that come within 0.05 AU of the Earth (an AU is one astronomical unit, the average distance between the Earth and the Sun).

These near-Earth asteroids (or NEAs for short, sometimes called NEOs, for near-Earth objects) aren’t necessarily going to impact the Earth. But they’re the most likely ones to do it; in all the billions of kilometers that encompass the wide expanse of our Solar System, these are the ones that live in our neighborhood.

And impact they do. The larger planets and moons of our Solar System are littered with the craterous scars of past violent collisions. The only reason the Earth doesn’t have the same amount of visible damage as, say, the Moon is that our planet constantly reshapes its surface through erosion and plate tectonics.

It’s through craters elsewhere that astronomers have built up a sense of how often a planet like the Earth experiences a serious impact and the typical sizes of those impactors.

Tiny things happen all the time. When you see a beautiful shooting star streaking across the night sky, that’s from the “impact” of an object somewhere between the size of a grain of sand and a tiny pebble striking our atmosphere at a few tens of thousands of kilometers per hour.

Every few years or so, an object 10 meters across hits us; when it does, it delivers energy roughly equivalent to that of our earliest atomic weapons. Thankfully, most of the Earth is open ocean, and most impactors of this class burst apart in the upper atmosphere, so we typically don’t have to worry too much about them.

The much larger—but thankfully much rarer—asteroids are what cause us heartburn. This is where we get into the delightful mathematics of attempting to calculate an existential risk to humanity.

At one end of the scale, we have the kind of stuff that kills dinosaurs and envelops the globe in a shroud of ash. These rocks are several kilometers across but only come into Earth-crossing trajectories every few million years. One of them would doom us—certainly our civilization and likely our species. The combination of the unimaginable scale of devastation and the incredibly small likelihood of it occurring puts this kind of threat almost beyond human comprehension—and intervention. For now, we just have to hope that our time isn’t up.

Then there are the in-betweeners. These are the space rocks starting at a hundred meters across. Upon impact, they release a minimum of 30 megatons of energy, which is capable of leaving a crater a couple of kilometers across. Those kinds of dangers present themselves roughly every 10,000 years.

That’s an interesting time scale. Our written history stretches back thousands of years, and our institutions have existed for thousands of years. We can envision our civilization, our ways of life, and our humanity continuing into the future for thousands of years.

This means that at some point, either we or our descendants will have to deal with a threat of this magnitude. Not a rock large enough to hit the big reset button on life but powerful enough to present a scale of disaster not yet seen in human history.

It’s full of stars

At first glance, the congressional mandate focusing on objects of at least 140 meters across seems a bit arbitrary. But that number comes from an intersection of risk and detection capabilities. Smaller rocks are more numerous and hit us more frequently. But even though they cause only slightly less damage, they are that much harder to detect.

As astronomical targets go, asteroids are challenging. They are small, not very reflective, and they move quickly. The smaller the size, the harder we have to work to spot it. So we’ve landed on 140 meters, corresponding roughly to an absolute magnitude of 22: the smallest kind of asteroid that poses a threat that we still can reliably and comprehensively detect with current technology and budgeting.

The reason we have yet to fulfill the congressional mandate is that most NEA/NEO surveys operate as side hustles for telescopes. For example, the Dark Energy Survey (DES), which utilizes a 4-meter telescope at the Cerro Tololo Inter-American Observatory in Chile, primarily focuses on surveying galaxies deep in cosmic history. But clever astronomers have been able to use spare time on the telescope to search for potentially hazardous asteroids.

Starting in 2025, NEO searches will get a big boost when the Vera C. Rubin Observatory finally achieves first light. Featuring an 8.4-meter primary mirror, the telescope will image the entire available sky every few nights, providing an unprecedented view of the heavens. With a mirror of that size, the observatory is more than capable of detecting NEOs. And with its rapid re-imaging, it can easily pick out the motions of asteroids. (Relatively speaking, of course—it still means sifting through absolute mountains of data with sophisticated algorithms).

The Rubin Observatory should be able to meet the congressional mandate in terms of identifying and tracking, but it still comes up short on one critical ability: characterizing. The problem is that there isn’t just one kind of asteroid. Some are loose piles of rubble. Others have dense cores of heavier elements. Some are almost spherical; others look like giant gray lumpy peanuts.

All these details matter when we attempt a threat assessment. Different asteroid compositions and geometries reflect sunlight in different ways, which subtly alters their orbits. Those subtle changes add up in time, leading to radically different pathways through the Solar System. And if a disaster were imminent, dealing with a loose pile of rubble requires a completely different strategy than if we were faced with a metal-rich asteroid.

Fully characterizing an asteroid takes repeated observations, monitoring how light reflects off it as it moves through its orbit and correlating measurements at different wavelengths.

Those observations are the job of the NEO Surveyor, set to launch no later than June 2028. It will work in conjunction with ground-based surveys to provide a network of overlapping observations to finally fulfill the congressional mandate—and warn us of any major threat.

A mighty wind

If you ever want to get a taste of how we would approach a potential threat, NASA’s Jet Propulsion Lab (JPL) has something right up your alley. JPL hosts the Center for Near Earth Object Studies, or CNEOS (who knew that preventing the extinction of our species would rely on so many acronyms). CNEOS scientists regularly host simulated exercises, in which a series of pretend observations transform a potentially hazardous object into a seriously dangerous one.

Let’s say that astronomers will one day be able to identify, track, and characterize a near-Earth asteroid. Alerts would be sent out worldwide, and more astronomers and more observatories would join in the effort. With more data would come better predictions; we would get a detailed geometry of the asteroid, its composition, and its future orbit. With every passing day, the uncertainties on its course would continue to shrink, the predictions narrowing down the areas on the surface of the Earth that have the maximum chance of impact.

It's at this stage that we would have two choices. We either move the rock or simply hold on for dear life. Thankfully, moving the rock is a viable option, as NASA’s Double Asteroid Redirection Test (DART) showed. Launched toward the tiny moonlet of the asteroid Didymos, the mission's goal was simple: slam into the asteroid. While “punching an asteroid in the face” might seem like the height of futility, the mission was a success, with the spacecraft making a measurable change in the asteroid’s orbit.

I am the keymaster

If we catch a threatening asteroid early enough, we don’t have to move it all that much. Asteroids regularly travel millions of kilometers, and even the tiniest of changes to their direction of travel or velocity compound quickly. In addition, Earth is positively miniscule compared to the vast expanses of nothingness that define the volume of our Solar System.

If humanity were sufficiently motivated, we could build an impact vessel, load it down with the cameras, targeting software, and thrusters that the DART mission had, and send it on its way. It would strike its target at a predetermined position and angle of impact, throwing the asteroid ever-so-slightly off course. The asteroid would then continue on its merry way, relatively unbothered by the impact with our deflector but on a slightly new orbit that hopefully never intersects the Earth.

But this only works if we see the asteroid early enough and have the depth of observations needed to fully characterize the size, shape, composition, and orbit of the asteroid. We could then reliably simulate the effects of the impact, both in terms of its effectiveness and the resulting changes in orbital dynamics.

That’s a lot of ifs. Compounding these issues is that predicting future orbits for such tiny objects is notoriously complicated. Yes, we may successfully throw a potentially Earth-crossing asteroid off course… into a new orbit that is all but guaranteed to strike our planet at some later date.

One of the ways this nonintuitive behavior is possible is through what are called keyholes. The gravitational environment of the solar system is complicated and ever-shifting, with every point in space influenced in some way by the arrangements of the massive planets. Most orbits within the Solar System are stable and predictable. But there are certain regions—the keyholes—where predicting future trajectories are almost impossible. The gravity is so complex in the keyholes that orbits become chaotic. An asteroid can enter a keyhole in one direction and come out in almost any other. The tiniest of changes to an asteroid’s orbit, say, from uneven surface heating due to slight color changes across the face of the asteroid, can lead to wildly different orbits if they take it through a keyhole.

So if we go about the game of deflecting asteroids, we have to ensure that their new trajectories don’t take them near any keyholes. If they do, we may just be jumping from one disaster to another—possibly one that allows way less time to react and prepare.

I don’t want to miss a thing

But maybe we could take dangerous asteroids and…blow them up. Yes, that is the plot of Armageddon. No, there will likely not be a rocking soundtrack to accompany the mission.

Altering trajectories of fast-moving, massive asteroids is hard. We need a lot of warning, and we have to make sure our calculations are on point.

The danger of a giant asteroid comes directly from its size, as it has more kinetic energy to deliver to our planet. A smaller rock traveling at the same speed would simply burn up in our atmosphere. That’s the driving logic behind PI, a new planetary defense initiative funded by NASA’s Innovative Advanced Concepts Program (disclosure notice: I serve on the advisory council for this program, so of course I think it’s cool).

The idea behind PI is simple. We find a large asteroid on a dangerous trajectory. We load a big bomb (preferably nuclear) on a rocket. We shoot it at the asteroid. The rocket buries itself as deeply as possible into the asteroid and blows up, fragmenting the large asteroid into many smaller ones.

Multiple studies have shown that most asteroids are “rubble piles”—just loose collections of boulders barely clinging together through their mutual gravitational attraction. If we were to try to blow up an asteroid, a few of those boulders would be flung away. Most of the asteroid would likely expand into fragments traveling on the same trajectory—a cosmic grapeshot.

But if we did it right, those smaller fragments would just burn up in our atmosphere, transforming an end-of-days killer asteroid into the most magnificent meteor shower the world has ever seen. Of course, this is just an interesting idea right now, still in the simulation phase.

We have our work cut out for us if we’re going to find a way to defend ourselves when our cosmic time is up.

Welcome to Edition 6.43 of the Rocket Report! This week saw the debut of two new rockets, a suborbital lifter from a German startup, and a new variant of the Long March 6 from China's state-owned launch provider. We also got within two hours of the debut of a crewed launch of Boeing's Starliner vehicle, but a rocket issue forced a 10-day delay. Soon, hopefully.

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.

Orbital launch tally running ahead of 2023. There were 63 orbital launch attempts worldwide in the first quarter of 2024, which is 10 more than the same time last year, Payload reports. SpaceX accounted for 32 of the 34 US orbital launch attempts in Q1. One ULA Vulcan launch and one Rocket Lab Electron launch out of Wallops rounded out the remaining total. (Rocket Lab flights out of New Zealand are not counted in US launch totals.)

SpaceX accounts for more than half ... SpaceX flew 31 Falcon missions and one Starship mission in Q1. The company’s launch attempts increased by 11 flights in Q1 2024 vs. Q1 2023. China’s Q1 launch was flat year over year at 14 flights, with its Long March 2 vehicle leading the way with four missions. Europe’s planned summer Ariane 6 launch can’t come soon enough, as the region saw zero launch attempts in the quarter.

Virgin Galactic will lean heavily on mothership. Virgin Galactic says it will fly its existing “mothership” aircraft more frequently than previously planned with its upcoming Delta-class suborbital spaceplanes, allowing the company to defer development of a new plane, Space News reports. In a May 7 earnings call, Virgin Galactic executives said they expect to fly their VMS Eve aircraft up to 125 times a year once the company starts commercial service of the Delta spaceplanes, the successor to the existing VSS Unity, in 2026.

Asking a lot of Eve ... “The planned increase in flight cadence for our mothership Eve is a game changer when our first two Delta ships enter commercial service,” added Doug Ahrens, chief financial officer of Virgin Galactic. That is a lot to ask of what was originally a developmental aircraft, which started flights in 2008. Eve was never intended to fly this many times, and it seems likely that refurbishment of the plane between launches could become a major bottleneck for Virgin Galactic as it seeks to scale up operations. (submitted by Ken the Bin)

HyImpulse conducts its first launch. The Germany-based startup launched a suborbital rocket from Southern Launch’s Koonibba Test Range in Australia late last week. The SR75 rocket's "Light this Candle!" mission was the inaugural launch attempt of HyImpulse’s booster, a pathfinder for an eventual orbital rocket. In a news release, the company characterized the flight as a "success" but did not specify what altitude the vehicle reached. Nominally, it is capable of flying to 250 km.

Literally lighting a candle ... "With this successful launch, which also provides us with valuable data for further development, we have validated our technical concept and demonstrated our market readiness," said Christian Schmierer, co-founder and co-CEO of HyImpulse. The German launch company is developing its rockets with hybrid technology, using solid paraffin (commonly known as candle wax) and liquid oxygen as fuel. HyImpulse aims to learn from this launch as it develops the SL1 multi-stage orbital launch vehicle, which may debut next year. (submitted by Marakai and Joey S-IVB)

Redesigned Vega C second stage ships. Italian rocket builder Avio has announced that it has shipped the first of its redesigned Vega C Zefiro 40 second stage to its testing facility in Sardinia, European Spaceflight reports. This development follows the failure of a Vega C rocket's second stage during just the second flight of the rocket in 2022, resulting in the loss of two Airbus Pléiades Neo Earth observation satellites. After several investigations, it was decided that the Zefiro 40 nozzle needed to be redesigned.

Test then fly ... On Thursday, Avio published the highlights of first-quarter financial results, which included an update on the Vega C rocket’s path back to flight. A static fire test of the stage is expected to be conducted between late May and early June. A second static fire test will complete qualification and could result in a launch of the next Vega C rocket by the end of this year. One item of concern for Avio is cash: According to the company’s Q1 financials, Avio reduced its net cash position by 66.6 million euros from the last quarter of 2024 to just 9.6 million euros. (submitted by EllPeaTea)

Swedish launch site gets first orbital customer. South Korea’s Perigee Aerospace has signed an agreement to launch its Blue Whale 1 rocket from Esrange Space Center in Sweden. Originally developed in the 1960s to launch suborbital rockets, the site is now managed by the government-owned Swedish Space Corporation. This would be the first orbital mission from the location. The first Blue Whale 1 launch from Esrange is expected no earlier than next year, European Spaceflight reports.

A reusable first stage? ... "SSC has an impressive 50 years of launch heritage, and the new orbital launch infrastructure at Esrange is laying the foundation for the years to come,” said Perigee founder and CEO Yoon Shin. Blue Whale 1 is a two-stage small-lift rocket that is intended to have a reusable first stage. The rocket may be capable of delivering up to 200 kg payloads into a 500 km Sun-synchronous orbit. (submitted by EllPeaTea)

Faulty valve scuttles Starliner’s first crew launch. Around two hours before the Starliner spacecraft was due to lift off on Monday evening atop an Atlas V rocket, United Launch Alliance stopped the countdown, Ars reports. The culprit was a misbehaving valve on the rocket's Centaur upper stage, which has two RL10 engines fed by super-chilled liquid hydrogen and liquid oxygen propellants. “We saw a self-regulating valve on the LOX (liquid oxygen) side had a bit of a buzz; it was moving in a strange behavior," said Steve Stich, NASA's commercial crew program manager. "The flight rules had been laid out for this flight ahead of time. With the crew at the launch pad, the proper action was to scrub.”

A short delay after years of waiting ... The next opportunity to launch Starliner on its first crew test flight will be May 17 at 6:16 pm EDT (22:16 UTC). Managers spent Tuesday reviewing data from the faulty valve and determined it should be replaced. This will require ULA to roll the Atlas V rocket back into its hangar about a third of a mile south of the launch pad, eliminating any chance to launch the mission later this week. The launch of Starliner has been long-awaited and is running years behind its original schedule. In a lengthy feature, Ars explored some of the reasons for these delays and challenges Boeing has overcome in developing the human spacecraft.

Neutron debut slips into 2025. After insisting that the reusable Neutron would be “on the pad” by year-end, Rocket Lab conceded during its first-quarter earnings release that the next-generation vehicle won’t launch until mid-2025, Payload reports. “The engine is the primary driver for the move,” chief executive Peter Beck said during the call. The company completed the build of the first Archimedes engine for the medium-lift rocket, which is now on its way to Stennis Space Center for hot fire testing.

A very difficult thing ... Rocket Lab is building five engines concurrently as it develops the manufacturing line for the new propulsion systems. “At the end of the day, this is a rocket program, and it’s a very difficult thing to execute—that’s why there are only a few of us in the world that have pulled this off,” Beck said. At the end of the day, we say that Neutron launching at any point in 2025 would be a big win for Rocket Lab. (submitted by Ken the Bin)

Polaris Dawn mission will push Falcon 9, Dragon mission. Commanded and funded by private astronaut Jared Isaacman, the Polaris Dawn mission seeks to test new technologies that will further the expansion of humanity into space, Ars reports. Among the objectives are pushing the performance of the Dragon spacecraft and Falcon 9 rocket, performing the first commercial spacewalk in a new spacesuit developed by SpaceX, and testing Starlink laser-based communications in space.

Flying high ... "Our first objective is to travel farther from the Earth and the last time humans walked on the Moon with Apollo 17, more than 50 years ago," Isaacman said. The mission will target an apogee of 1,400 kilometers. The Polaris Dawn mission does not have a launch date, but SpaceX officials confirmed that it is now the next crewed mission the company will fly. There are several scheduling issues at play, but it's possible the mission could launch within the next six to eight weeks. It's likely the Falcon 9 first stage that launched a Starlink mission on Wednesday, B.1083, will be used for the mission.

Long March 6C makes its debut. The new Long March 6C rocket successfully inserted four satellites into orbit late Monday on its debut flight, Space News reports. The new, 43-meter-tall rocket is the latest in a line of new-generation rockets developed by the Shanghai Academy of Spaceflight Technology in the Long March 6 series. It is a shorter variant of the Long March 6A and has a carrying capacity of 2.4 metric tons to a 500 km Sun-synchronous orbit.

Less toxic rockets, please ... The new Long March rockets are part of a new generation of Chinese rockets that use kerosene and liquid oxygen instead of toxic hypergolic propellant. The launch was China’s 20th of 2024 and follows the May 3 launch of the Chang’e-6 sample return mission. China aims to launch around 100 times this year, but at the country's current pace, it will fall well short of this target. (submitted by Ken the Bin)

Space Florida studies options for expanding port operations. In response to growing demand for commercial space operations at Port Canaveral—principally the recovery and off-loading of Falcon 9 first-stage boosters, but with other providers expected to join in soon—Space Florida conducted a study to consider expansion options. "While Port Canaveral supports the commercial space industry, existing infrastructure does not have capacity to meet the demands of the expected exponential growth in the space transportation industry," the study found.

Responding to market demand ... Anticipating growth in launch and recovery operations by as much as a factor of 10 over the next half century, the Space Florida study sees the need for significant growth. "Current facilities at Port Canaveral and surrounding areas are insufficient to meet the projected demand for maritime operations related to space launches, necessitating over 9,000 linear feet of dedicated wharf space," the study concluded. (submitted by Ken the Bin)

China launches third lunar mission in five years. Last Friday, the country launched its largest rocket, the Long March 5, carrying an orbiter, lander, ascent vehicle, and a return spacecraft. The combined mass of the Chang'e-6 spacecraft is about 8 metric tons, and it will attempt to return rocks and soil from the far side of the Moon—something scientists have never been able to study before in-depth. The mission's goal is to bring about 2 kg (4.4 pounds) of rocks back to Earth a little more than a month from now, Ars reports.

Building toward human landings ... Chang'e-6 builds upon the Chinese space program's successful lunar program. In 2019, the Chang'e-4 mission made a soft landing on the far side of the Moon, the first time this had ever been done by a spacecraft. The far side is more challenging than the near side, because line-of-sight communications are not possible with Earth. Then, in late 2020, the Chang'e-5 mission landed on the near side of the Moon and successfully collected 1.7 kg of rocks. These were subsequently blasted off the surface of the Moon and returned to China. Nominally, China's current plan calls for the first landing of two taikonauts on the surface of the Moon in 2029 or 2030. (submitted by Ken the Bin)

Next three launches

May 10: Falcon 9 | Starlink 8-2 | Vandenberg Space Force Base | 03:20 UTC

May 11: Long March 4C | Unknown payload | Jiuquan Satellite Launch Center, China | 11:45 UTC

May 13: Falcon 9 | Starlink 6-58 | Cape Canaveral Space Force Station, Florida | 12:11 UTC

Heat pumps are the most energy-efficient way of controlling indoor temperature. By moving heat between locations, they avoid the inefficiencies of generating heat in the first place. But that doesn't mean they can't be made more efficient.

Most current heat pumps rely on materials that exhibit large changes in temperature in response to changing pressures, but the energy required to pressurize them gets lost when they're cycled back to a low-pressure state, absorbing heat from their surroundings. That has gotten people interested in electrocaloric devices, where changes in temperature are driven by storing charges in a material. Since it essentially acts as a big capacitor, much of the electrical energy involved can be pulled back out as the system cycles.

But capacitors aren't especially mobile, so electrocaloric systems tended to use fluids to move heat into and out of the capacitor as it cycles. Now, however, researchers have developed an electrocaloric system that moves itself between hot and cold environments, radically simplifying the system and eliminating some of the energy required for it to operate. They even demonstrate it effectively cooling a computer chip.

Electrocalorics and heat pumps

Late last year, we covered a paper that described a demonstration electrocaloric system. It operated pretty simply: Pumping electrons into a capacitor caused a phase transition in its internal electronic structure. While this phase transition doesn't involve melting or freezing, it is associated with a major change in the capacitor's heat content.

But, on its own, that won't operate as a heat pump. While it will happily either heat or cool its immediate environment (depending on whether it's being charged or discharged), that doesn't help you transfer heat between environments. To heat or cool an environment, you need to move heat energy out of or into the capacitor. The team that developed this device did so by simply pumping water.

So, to act as a cooling device, the electrocaloric capacitor would first heat up water that would then be pumped to where it could radiate that heat away to the environment. New water would then be pumped in, which the capacitor would cool during discharge. That cool water would then be pumped to where it could absorb heat from the area that was meant to be cooled.

It definitely works, but there is an energy cost associated with doing that pumping. The new work, done by researchers at the Shanghai Jiao Tong University, gets rid of the need for any pumping. Instead, the capacitor itself moves between the heat source and heat sink. And it does so when powered by the same thing that triggers the temperature change: being charged or discharged.

The work relies on a polymer called poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene), a name so complex that even the abbreviation is excessively long (we'll just refer to "the polymer"). It's a known electrocaloric material, but variants of the polymer with a different chemical bonding structure have a different response to picking up charges: They change shape.

So, the researchers spent a fair bit of time testing chemical reactions that produced polymers with different frequencies of double bonds, attempting to maximize both effects: electrocaloric temperature changes and charge-driven shape changes. This was undoubtedly a significant amount of work, but it takes up roughly three sentences in the paper. In any case, with the chemistry sorted out, they could make a single polymer that had strong temperature and shape responses.

Putting it to work

Turning that into a heat pump is remarkably simple. Let's say you have a surface you want to cool down. You simply arrange the polymer so that its shape after discharge (which cools the polymer) leaves it physically touching that surface. Then, when you add charge to it, it will both change shape to move away from the surface and start heating up. If you arrange things so that it comes in contact with a second surface at this point—say a heat sink or a large reservoir of water—it will dump its heat into that and return to ambient temperature and be ready to start the cycle all over again.

In other words, the polymer would move itself between warmer and cooler environments and do so in response to the same process that causes it to change temperature. If you can get the geometry to work out, then it's a single-material heat pump that is powered by charging and discharging a capacitor—with most of the electrons used to do the charging still available to power something else when the cycle is complete. It can also work for heating or cooling, depending on how you configure the system.

And it works. The researchers configured a setup where the polymer acted as a cooling system for a computer chip that would normally be operating at 60° C. With the electrocaloric system operating, the chip's temperature dropped by 18° C. By contrast, a cooling fan only dropped the chip's temperature by 7° C.

The material is also remarkably durable, with no drop in performance seen after 70,000 cycles. They also showed it was possible to build an array of as many as 260 individual polymer devices to cool larger objects, which was able to transfer heat with an efficiency of about a third of the maximum allowed by the second law of thermodynamics.

Capacitors with lots of potential

The researchers found that the key determinant of performance was the interaction between the surface of the polymer and the material it was transferring heat to or from. Optimizing this thermal contact, they write, will be "essential to further enhance the performance of the self-oscillating electrocaloric device."

While individual pieces of polymer may not be able to drive huge temperature differences (although a 17° C difference is not at all bad), it's also easy to see how you can build a device with lots of these pieces of polymer in series, with pairs of polymers flipping between different sides of a single metal plate. Depending on how many layers of devices you make, you could control the size of the overall temperature gradient.

This may not completely eliminate the need for some sort of working fluid to transfer heat over longer distances. Things like water heaters in the basement or computer chips are typically in environments where a large source of ambient temperatures can be some distance away. But the nature of that fluid really doesn't matter—it could easily be water. So this development has the potential of freeing us from the chemicals that are currently used in most heat pumps, which are typically potent greenhouse gases.

Nature, 2024. DOI: 10.1038/s41586-024-07375-3  (About DOIs).

The field of dentistry is lagging on adopting evidence-based care and, as such, is rife with overdiagnoses and overtreatments that may align more with the economic pressures of keeping a dental practice afloat than what care patients actually need. At least, that's according to a trio of health and dental researchers from Brazil and the United Kingdom, led by epidemiologist and dentist Paulo Nadanovsky, of the University of the State of Rio de Janeiro.

In a viewpoint published Monday in JAMA Internal Medicine, the researchers point out that many common—nearly unquestioned—practices in dentistry aren't backed up by solid data. That includes the typical recommendation that everyone should get a dental check-up every six months. The researchers note that two large clinical trials failed to find a benefit of six-month check-ups compared with longer intervals that were up to two years.

A 2020 Cochrane review that assessed the two clinical trials concluded that "whether adults see their dentist for a check‐up every six months or at personalized intervals based on their dentist's assessment of their risk of dental disease does not affect tooth decay, gum disease, or quality of life. Longer intervals (up to 24 months) between check‐ups may not negatively affect these outcomes." The Cochrane reviewers reported that they were "confident" of little to no difference between six-month and risk-based check-ups and were "moderately confident" that going up to 24-month checkups would make little to no difference either.

Likewise, Nadanovsky and his colleagues highlight that there is no evidence supporting the benefit of common scaling and polishing treatments for adults without periodontitis. And for children, cavities in baby teeth are routinely filled, despite evidence from a randomized controlled trial that rates of pain and infections are similar—about 40 percent—whether the cavities are filled or not.

As for the disconnect between common practices and the state of the evidence, the researchers suggest that economic pressures are largely to blame, as well as the training and opinions of practicing dentists and the expectations of patients—"all of which tend to favor excessive diagnoses and interventions," the researchers write. The problem may date back to the 1970s and 1980s when fluoridated toothpaste became common, and the rate of cavities saw an "extraordinary decline." That left dentists with a financial need to find new ways to keep their offices filled, even if teeth didn't need to be.

And this created two problems: People being overtreated or not treated at all, the researchers wrote.

The prevailing dental economic model based on fee-for-service creates an environment of dental overdiagnosis and overtreatment. At the same time, many persons who do not have dental insurance cannot afford to pay out of pocket for dental care, creating a situation where people with low income or who are part of a racial and ethnic minority group are often underdiagnosed and undertreated.

The researchers called for more clinical trials to assess the effectiveness and benefits of treatments and to have dental guidelines updated accordingly. Then, Nadanovsky and colleagues said, resources can be allocated to the patients who need them the most. "The aim is to reduce overdiagnosis and overtreatment while increasing necessary treatment," they conclude.

In a lengthy statement to Ars, the American Dental Association responded to the viewpoint by saying that it is "dedicated to evidence-based dentistry." The ADA defined evidence-based dentistry as that which "integrates the dentist’s clinical expertise, the patient’s needs and preferences, and the most current, clinically relevant data. All three are part of the decision-making process for patient care."

The ADA did not respond directly to questions regarding the shaky evidence behind common practices and recommendations, such as six-month check-ups. (The ADA does not recommend a specific interval between visits but recommends seeing a dentist "regularly.") Instead, the ADA emphasized that the "dentist-patient relationship is critically important." While noting the "ethical responsibility of dentists," the ADA focused on the role of patients in their care. According to the ADA, patients should be selective in finding a dentist, receive dental care cost estimates upfront, and always ask questions and discuss alternatives. The association also referenced its statement on dental patient rights and responsibilities.

"Patients always have the option to discuss alternative treatment plans, decline care, or seek another opinion," the ADA told Ars.

"The nation’s dentists have long sought to turn the tide of untreated oral disease and advise people to visit their dentist regularly for recommendations specific to their individual needs developed in accordance with the latest scientific evidence available," the ADA said.

Astronauts Butch Wilmore and Suni Williams climbed into their seats inside Boeing's Starliner spacecraft Monday night in Florida, but trouble with the capsule's Atlas V rocket kept the commercial ship's long-delayed crew test flight on the ground.

Around two hours before launch time, shortly after 8:30 pm EDT (00:30 UTC), United Launch Alliance's launch team stopped the countdown. "The engineering team has evaluated, the vehicle is not in a configuration where we can proceed with flight today," said Doug Lebo, ULA's launch conductor.

The culprit was a misbehaving valve on the rocket's Centaur upper stage, which has two RL10 engines fed by super-cold liquid hydrogen and liquid oxygen propellants.

“We saw a self-regulating valve on the LOX (liquid oxygen) side had a bit of a buzz; it was moving in a strange behavior," said Steve Stich, NASA's commercial crew program manager. "The flight rules had been laid out for this flight ahead of time. With the crew at the launch pad, the proper action was to scrub.”

The next opportunity to launch Starliner on its first crew test flight will be Friday night at 9 pm EDT (01:00 UTC Saturday). NASA announced overnight that officials decided to skip a launch opportunity Tuesday night to allow engineers more time to study the valve problem and decide whether they need to replace it.

Work ahead

Everything else was going smoothly in the countdown Monday night. This mission will also be the first time astronauts have flown on ULA's Atlas V rocket, which has logged 99 successful flights since 2002. It is the culmination of nearly a decade-and-a-half of development by Boeing, which has a $4.2 billion contract with NASA to ready Starliner for crew missions, then carry out six long-duration crew ferry flights to and from the International Space Station.

This crew test flight will last at least eight days, taking Wilmore and Williams to the space station to verify Starliner's readiness for operational missions. Once Starliner flies, NASA will have two human-rated spacecraft on contract. SpaceX's Crew Dragon has been in service since 2020.

When officials scrubbed Monday night's launch attempt, Wilmore and Williams were already aboard the Starliner spacecraft on top of the Atlas V rocket at Cape Canaveral Space Force Station, Florida. The Boeing and ULA support team helped them out of the capsule and drove them back to crew quarters at the nearby Kennedy Space Center to wait for the next launch attempt.

"I promised Butch and Suni a boring evening," said Tory Bruno, ULA's CEO. "I didn’t mean for it to be quite this boring, but we’re going to follow our rules, and we’re going to make sure that the crew is safe."

When the next launch attempt actually occurs depends on whether ULA engineers determine they can resolve the problem without rolling the Atlas V rocket back to its hangar for repairs.

The valve in question vents gas from the liquid oxygen tank on the Centaur upper stage to maintain the tank at proper pressures. This is important for two reasons. The tank needs to be at the correct pressure for the RL10 engines to receive propellant during the flight, and the Centaur upper stage itself has ultra-thin walls to reduce weight, and requires pressure to maintain structural integrity.

Around an hour before ULA scrubbed the launch attempt, the launch team noticed oscillations in measurements at the top of the Centaur liquid oxygen tank. The ground crew at the launch pad, a few feet from the rocket, reported an unusual "chattering" sound at the same time.

This chattering or buzzing sound was associated with rapid movement of the relief valve. In this case, it was cycling about 40 times per second.

"Every now and again, on rare occasions, a valve like that can get into a position where it’s just off the seat," Bruno said. "Its temperature, its stiffness, everything is just right and it will flutter, or it’ll buzz in this base. It will cycle. We’ve seen that before."

On previous occasions, such as on an Atlas V launch in 2015, ULA's launch team commanded the valve closed and reopened the valve, and the buzzing motion stopped. This allowed the launch to proceed successfully. For safety reasons, ULA didn't want to take that step with the astronauts inside the Starliner spacecraft atop the rocket, so they waited until the crew departed the launch pad Monday night.

"It has, in fact, stopped," Bruno said. "Once we got the crew off, we cycled the valve and it stopped buzzing. If this was a satellite, that is our standard procedures, and the satellite would already be in orbit. But that changes the state of the fueled Centaur, and we don’t do that when people are present. So our flight rules called for us to scrub and take the crew off before we cycled that valve."

ULA engineers are analyzing data to determine whether the rapid cycling of the relief valve consisted of full open and close cycles or whether the valve was moving a fraction of its full range of motion. The valve has been tested to show it can sustain at least 200,000 cycles and still function normally.

If the buzzing behavior noticed Monday night was caused by full open and close cycles, engineers determined the valve was nearing that 200,000-cycle limit.

"What we are analyzing tonight is data that would help us understand, were these full cycles ... or were these low amplitude, low energy buzzes against the seat, in which case we would calculate that equivalent energy and we would have an equivalent count of cycles," Bruno said. "If they are significantly less than the 200,000, then we might feel we have enough life to attempt another launch.”

In that situation, officials could give the green light to proceed with another countdown Friday evening.

However, if managers decide the valve is nearing its operational limit, teams will roll the Atlas V and Starliner back to ULA's vertical hangar about a third of a mile south of the launch pad. There, technicians would change out the valve, a process that Bruno said would take a few days. The Atlas V could return to the launch pad as soon as this weekend.

Stich said the Starliner test flight has launch opportunities available Tuesday, Friday, and Saturday, then the next launch dates would be in the middle of next week, perhaps May 14 and 15. Officials want to ensure the Starliner spacecraft can launch on a trajectory to reach the space station within about 24 hours of launch. This means the position of the space station in its orbit precludes launch opportunities on some days.