Science – Page 17

Study: Megalodon’s body shape was closer to a lemon shark

aquatic animals, megalogon, paleontology, Science / Beth Washington / March 10, 2025

the mighty, mighty megalodon

Also: Baby megalodons were likely the size of great white sharks and capable of hunting marine mammals

The giant extinct shark species known as the megalodon has captured the interest of scientists and the general public alike, even inspiring the 2018 blockbuster film The Meg. The species lived some 3.6 million years ago and no complete skeleton has yet been found. So there has been considerable debate among paleobiologists about megalodon’s size, body shape and swimming speed, among other characteristics.

While some researchers have compared megalodon to a gigantic version of the stocky great white shark, others believe the species had a more slender body shape. A new paper published in the journal Palaeontologia Electronica bolsters the latter viewpoint, also drawing conclusions about the megalodon’s body mass, swimming speed (based on hydrodynamic principles), and growth patterns.

As previously reported, the largest shark alive today, reaching up to 20 meters long, is the whale shark, a sedate filter feeder. As recently as 4 million years ago, however, sharks of that scale likely included the fast-moving predator megalodon (formally Otodus megalodon). Due to incomplete fossil data, we’re not entirely sure how large megalodons were and can only make inferences based on some of their living relatives.

Thanks to research published in 2023 on its fossilized teeth, we’re now fairly confident that megalodon shared something else with these relatives: it wasn’t entirely cold-blooded and kept its body temperature above that of the surrounding ocean. Most sharks, like most fish, are ectothermic, meaning that their body temperatures match those of the surrounding water. But a handful of species, part of a group termed mackerel sharks, are endothermic: They have a specialized pattern of blood circulation that helps retain some of the heat their muscles produce. This enables them to keep some body parts at a higher temperature than their surroundings.

Of particular relevance to this latest paper is a 2022 study by Jack Cooper of Swansea University in the UK and his co-authors. In 2020, the team reconstructed a 2D model of the megalodon, basing the dimensions on similar existing shark species. The researchers followed up in 2022 with a reconstructed 3D model, extrapolating the dimensions from a megalodon specimen (a vertebral column) in Belgium. Cooper concluded that a megalodon would have been a stocky, powerful shark—measuring some 52 feet (16 meters) in length with a body mass of 67.86 tons—able to execute bursts of high speed to attack prey, much like the significantly smaller great white shark.

(H) One of the largest vertebrae of Otodus meg- alodon; (I and J) CT scans showing cross-sectional views. — (H) One of the largest vertebrae of *Otodus megalodon*; (I and J) CT scans showing cross-sectional views. Credit: Shimada et al., 2025

Not everyone agreed, however, Last year, a team of 26 shark experts led by Kesnshu Shimada, a paleobiologist at DePaul University, further challenged the great white shark comparison, arguing that the super-sized creature’s body was more slender and possibly even longer than researchers previously thought. The team concluded that based on the spinal column, the combination of a great white build with the megalodon’s much longer length would have simply proved too cumbersome.

A fresh approach

Now Shimada is back with a fresh analysis, employing a new method that he says provides independent lines of evidence for the megalodon’s slender build. “Our new study does not use the modern great white shark as a model, but rather simply asks, ‘How long were the head and tail based on the trunk [length] represented by the fossil vertebral column?’ using the general body plan seen collectively in living and fossil sharks,” Shimada told Ars.

Shimada and his co-authors measured the proportions of 145 modern and 20 extinct species of shark, particularly the head, trunk, and tail relative to total body length. Megalodon was represented by a Belgian vertebral specimen. The largest vertebra in that specimen measured 15.5 centimeters (6 inches) in diameter, although there are other megalodon vertebrae in Denmark, for example, with diameters as much as 23 centimeters (9 inches).

Based on their analysis, Shimada et al, concluded that, because the trunk section of the Belgian specimen measured 11 meters, the head and tail were probably about 1.8 meters (6 feet) and 3.6 meters (12 feet) long, respectively, with a total body length of 16.4 meters (54 feet) for this particularly specimen. That means the Danish megalodon specimens could have been as long as 24.3 meters (80 feet). As for body shape, taking the new length estimates into account, the lemon shark appears to be closest modern analogue. “However, the exact position and shape of practically all the fins remain uncertain,” Shimada cautioned. “We are only talking about the main part of the body.”

Revised tentative body outline of 24.3 meters (80 feet) extinct megatooth shark, Otodus megalodon. — Credit: DePaul University/Kenshu Shimada

The team also found that a 24.3-meter-long megalodon would have weighed a good 94 tons with an estimated swimming speed of 2.1-3.5 KPM (1.3-2.2 MPH). They also studied growth patterns evident in the Belgian vertebrae, concluding that the megalodon would give live birth and that the newborns would be between 3.6 to 3.9 meters (12-13 feet) long—i.e., roughly the size of a great white shark. The authors see this as a refutation of the hypothesis that megalodons relied on nursery areas to rear their young, since a baby megalodon would be quite capable of hunting and killing marine mammals based on size alone.

In addition, “We unexpectedly unlocked the mystery of why certain aquatic vertebrates can attain gigantic sizes while others cannot,” Shimada said. “Living gigantic sharks, such as the whale shark and basking shark, as well as many other gigantic aquatic vertebrates like whales have slender bodies because large stocky bodies are hydrodynamically inefficient for swimming.”

That’s in sharp contrast to the great white shark, whose stocky body becomes even stockier as it grows. “It can be ‘large’ but cannot [get] past 7 meters (23 feet) to be ‘gigantic’ because of hydrodynamic constraints,” said Shimada. “We also demonstrate that the modern great white shark with a stocky body hypothetically blown up to the size of megalodon would not allow it to be an efficient swimmer due to the hydrodynamic constraints, further supporting the idea that it is more likely than not that megalodon must have had a much slenderer body than the modern great white shark.”

Shimada emphasized that their interpretations remain tentative but they are based on hard data and make for useful reference points for future research.

An “exciting working hypothesis”

For his part, Cooper found a lot to like in Shimada et al.’s latest analysis. “I’d say everything presented here is interesting and presents an exciting working hypothesis but that these should also be taken with a grain of salt until they can either be empirically tested, or a complete skeleton of megalodon is found to confirm one way or the other,” Cooper told Ars. “Generally, I appreciate the paper’s approach to its body size calculation in that it uses a lot of different shark species and doesn’t make any assumptions as to which species are the best analogues to megalodon.”

Shark biologists now say a lemon shark, like this one, is a better model of the extinct megalodon's body than the great white shark. — Shark biologists now say a lemon shark, like this one, is a better model of the extinct megalodon’s body than the great white shark. Credit: Albert Kok

Cooper acknowledged that it makes sense that a megalodon would be slightly slower than a great white given its sheer size, “though it does indicate we’ve got a shark capable of surprisingly fast speeds for its size,” he said. As for Shimada’s new growth model, he pronounced it “really solid” and concurred with the findings on birthing with one caveat. “I think the refutation of nursery sites is a bit of a leap, though I understand the temptation given the remarkably large size of the baby sharks,” he said. “We have geological evidence of multiple nurseries—not just small teeth, but also geological evidence of the right environmental conditions.”

He particularly liked Shinada et al.’s final paragraph. “[They] call out ‘popular questions’ along the lines of, ‘Was megalodon stronger than Livyatan?'” said Cooper. “I agree with the authors that these sorts of questions—ones we all often get asked by ‘fans’ on social media—are really not productive, as these unscientific questions disregard the rather amazing biology we’ve learned about this iconic, real species that existed, and reduce it to what I can only describe as a video game character.”

Regardless of how this friendly ongoing debate plays out, our collective fascination with megalodon is likely to persist. “It’s the imagining of such a magnificently enormous shark swimming around our oceans munching on whales, and considering that geologically speaking this happened in the very recent past,” said Cooper of the creature’s appeal. “It really captures what evolution can achieve, and even the huge size of their teeth alone really put it into perspective.”

DOI: Palaeontologia Electronica, 2025. 10.26879/1502 (About DOIs).

Jennifer is a senior writer at Ars Technica with a particular focus on where science meets culture, covering everything from physics and related interdisciplinary topics to her favorite films and TV series. Jennifer lives in Baltimore with her spouse, physicist Sean M. Carroll, and their two cats, Ariel and Caliban.

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Huh? The valuable role of interjections

history of language, language, Science, syndication / 9u50fv / March 9, 2025

Utterances like um, wow, and mm-hmm aren’t garbage—they keep conversations flowing.

Interjections—one-word utterances that aren’t part of a larger sentence—used to be dismissed as irrelevant linguistic detritus. But some linguists now think they play an essential role in regulating conversations. Credit: Daniel Garcia/Knowable Magazine

Listen carefully to a spoken conversation and you’ll notice that the speakers use a lot of little quasi-words—mm-hmm, um, huh? and the like—that don’t convey any information about the topic of the conversation itself. For many decades, linguists regarded such utterances as largely irrelevant noise, the flotsam and jetsam that accumulate on the margins of language when speakers aren’t as articulate as they’d like to be.

But these little words may be much more important than that. A few linguists now think that far from being detritus, they may be crucial traffic signals to regulate the flow of conversation as well as tools to negotiate mutual understanding. That puts them at the heart of language itself—and they may be the hardest part of language for artificial intelligence to master.

“Here is this phenomenon that lives right under our nose, that we barely noticed,” says Mark Dingemanse, a linguist at Radboud University in the Netherlands, “that turns out to upend our ideas of what makes complex language even possible in the first place.”

For most of the history of linguistics, scholars have tended to focus on written language, in large part because that’s what they had records of. But once recordings of conversation became available, they could begin to analyze spoken language the same way as writing.

When they did, they observed that interjections—that is, short utterances of just a word or two that are not part of a larger sentence—were ubiquitous in everyday speech. “One in every seven utterances are one of these things,” says Dingemanse, who explores the use of interjections in the 2024 Annual Review of Linguistics. “You’re going to find one of those little guys flying by every 12 seconds. Apparently, we need them.”

Many of these interjections serve to regulate the flow of conversation. “Think of it as a tool kit for conducting interactions,” says Dingemanse. “If you want to have streamlined conversations, these are the tools you need.” An um or uh from the speaker, for example, signals that they’re about to pause, but aren’t finished speaking. A quick huh? or what? from the listener, on the other hand, can signal a failure of communication that the speaker needs to repair.

That need seems to be universal: In a survey of 31 languages around the world, Dingemanse and his colleagues found that all of them used a short, neutral syllable similar to huh? as a repair signal, probably because it’s quick to produce. “In that moment of difficulty, you’re going to need the simplest possible question word, and that’s what huh? is,” says Dingemanse. “We think all societies will stumble on this, for the same reason.”

Other interjections serve as what some linguists call “continuers,” such as mm-hmm — signals from the listener that they’re paying attention and the speaker should keep going. Once again, the form of the word is well suited to its function: Because mm-hmm is made with a closed mouth, it’s clear that the signaler does not intend to speak.

Sign languages often handle continuers differently, but then again, two people signing at the same time can be less disruptive than two people speaking, says Carl Börstell, a linguist at the University of Bergen in Norway. In Swedish Sign Language, for example, listeners often sign yes as a continuer for long stretches, but to keep this continuer unobtrusive, the sender tends to hold their hands lower than usual.

Different interjections can send slightly different signals. Consider, for example, one person describing to another how to build a piece of Ikea furniture, says Allison Nguyen, a psycholinguist at Illinois State University. In such a conversation, mm-hmm might indicate that the speaker should continue explaining the current step, while yeah or OK would imply that the listener is done with that step and it’s time to move on to the next.

Wow! There’s more

Continuers aren’t merely for politeness—they really matter to a conversation, says Dingemanse. In one classic experiment from more than two decades ago, 34 undergraduate students listened as another volunteer told them a story. Some of the listeners gave the usual “I’m listening” signals, while others—who had been instructed to count the number of words beginning with the letter t—were too distracted to do so. The lack of normal signals from the listeners led to stories that were less well crafted, the researchers found. “That shows that these little words are quite consequential,” says Dingemanse.

Nguyen agrees that such words are far from meaningless. “They really do a lot for mutual understanding and mutual conversation,” she says. She’s now working to see if emojis serve similar functions in text conversations.

Storytellers depend on feedback such as mm-hmm and other interjections from their listeners. In this experiment, some listeners were told to count the number of times the storyteller used a word starting with t—a challenging task that prevented them from giving normal feedback. The quality of storytelling declined significantly, with problems like abrupt endings, rambling on, uneven or choppy pacing and overexplaining or justifying the point. Credit: Knowable Magazine

The role of interjections goes even deeper than regulating the flow of conversation. Interjections also help in negotiating the ground rules of a conversation. Every time two people converse, they need to establish an understanding of where each is coming from: what each participant knows to begin with, what they think the other person knows and how much detail they want to hear. Much of this work—what linguists call “grounding”—is carried out by interjections.

“If I’m telling you a story and you say something like ‘Wow!’ I might find that encouraging and add more detail,” says Nguyen. “But if you do something like, ‘Uh-huh,’ I’m going to assume you aren’t interested in more detail.”

A key part of grounding is working out what each participant thinks about the other’s knowledge, says Martina Wiltschko, a theoretical linguist at the Catalan Institution for Research and Advanced Studies in Barcelona, Spain. Some languages, like Mandarin, explicitly differentiate between “I’m telling you something you didn’t know” and “I’m telling you something that I think you knew already.” In English, that task falls largely on interjections.

One of Wiltschko’s favorite examples is the Canadian eh? “If I tell you you have a new dog, I’m usually not telling you stuff you don’t know, so it’s weird for me to tell you,” she says. But ‘You have a new dog, eh?’ eliminates the weirdness by flagging the statement as news to the speaker, not the listener.

Other interjections can indicate that the speaker knows they’re not giving the other participant what they sought. “If you ask me what’s the weather like in Barcelona, I can say ‘Well, I haven’t been outside yet,’” says Wiltschko. The well is an acknowledgement that she’s not quite answering the question.

Wiltschko and her students have now examined more than 20 languages, and every one of them uses little words for negotiations like these. “I haven’t found a language that doesn’t do these three general things: what I know, what I think you know and turn-taking,” she says. They are key to regulating conversations, she adds: “We are building common ground, and we are taking turns.”

Details like these aren’t just arcana for linguists to obsess over. Using interjections properly is a key part of sounding fluent in speaking a second language, notes Wiltschko, but language teachers often ignore them. “When it comes to language teaching, you get points deducted for using ums and uhs, because you’re ‘not fluent,’” she says. “But native speakers use them, because it helps! They should be taught.” Artificial intelligence, too, can struggle to use interjections well, she notes, making them the best way to distinguish between a computer and a real human.

And interjections also provide a window into interpersonal relationships. “These little markers say so much about what you think,” she says—and they’re harder to control than the actual content. Maybe couples therapists, for example, would find that interjections afford useful insights into how their clients regard one another and how they negotiate power in a conversation. The interjection oh often signals confrontation, she says, as in the difference between “Do you want to go out for dinner?” and “Oh, so now you want to go out for dinner?”

Indeed, these little words go right to the heart of language and what it is for. “Language exists because we need to interact with one another,” says Börstell. “For me, that’s the main reason for language being so successful.”

Dingemanse goes one step further. Interjections, he says, don’t just facilitate our conversations. In negotiating points of view and grounding, they’re also how language talks about talking.

“With huh? you say not just ‘I didn’t understand,’” says Dingemanse. “It’s ‘I understand you’re trying to tell me something, but I didn’t get it.’” That reflexivity enables more sophisticated speech and thought. Indeed, he says, “I don’t think we would have complex language if it were not for these simple words.”

Knowable Magazine explores the real-world significance of scholarly work through a journalistic lens.

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White House may seek to slash NASA’s science budget by 50 percent

nasa budget, Science, Space / Beth Washington / March 9, 2025

In many ways, NASA’s science directorate is the crown jewel of the space agency. Nearly all of the most significant achievements over the last 25 years have been delivered by the science programs: Ingenuity flying on Mars, New Horizons swooping by Pluto, images from the James Webb Space Telescope, the discovery of thousands of exoplanets, the return of samples from asteroids and comets, Cassini’s discovery of water plumes on Enceladus, a continuous robotic presence on Mars, and so much more. Even the recent lunar landings by Firefly and Intuitive Machines were funded by NASA’s science directorate.

Of NASA’s roughly $25 billion budget, however, only about 30 percent is allocated to science. For fiscal year 2024, this amounted to $7.4 billion. This spending was broken down into approximately $2.7 billion for planetary science, $2.2 billion for Earth science, $1.5 billion for astrophysics, and $800 million for heliophysics.

NASA science funding since 1980. Credit: Casey Dreier/The Planetary Society

The proposed cuts are being driven by Russell Vought, the recently confirmed director of the White House Office of Management and Budget, which sets budget and policy priorities for a presidential administration. In some sense, the budgetary decisions should not come as a surprise, as they are consistent with what Vought proposed in a “shadow” budget for fiscal-year 2023 as part of his Center for Renewing America.

“The budget also proposes a 50 percent reduction in NASA Science programs and spending, reducing their misguided Carbon Reduction System spending and Global Climate Change programs,” Vought’s organization wrote in its report published in December 2022.

Zeroing out Earth science?

Despite Vought’s desire, however, NASA is expressly charged with studying our planet.

The congressional act that created NASA in 1958 calls for the space agency to expand human knowledge about Earth’s atmosphere and space, and the agency’s Earth observation satellites have substantially increased our understanding of this planet’s weather, changing climate, and land use.

Even if NASA’s Earth science budget were taken to zero, cutting the overall science budget in half would still dramatically reduce funding in planetary science as well as other research areas. Scientists told Ars that NASA would be forced to make difficult decisions, likely including shutting off extended missions such as the Voyager and Curiosity probes on Mars, and possibly even the Hubble Space Telescope. It might be possible to save missions in later stages of development, such as the Dragonfly probe to Saturn’s moon Titan, and the NEO Surveyor mission to search for hazardous asteroids. But it would be impossible to start meaningful new missions to explore the Solar System, potentially setting back planetary exploration a decade.

White House may seek to slash NASA’s science budget by 50 percent Read More »

New research shows bigger animals get more cancer, defying decades-old belief

animal research, cancer, cancer research, Science, syndication / 9u50fv / March 8, 2025

The answer lies in how quickly body size evolves. We found that birds and mammals that reached large sizes more rapidly have reduced cancer prevalence. For example, the common dolphin, Delphinus delphis evolved to reach its large body size—along with most other whales and dolphins (referred to as cetaceans) about three times faster than other mammals. However, cetaceans tend to have less cancer than expected.

Larger species face higher cancer risks but those that reached that size rapidly evolved mechanisms for mitigating it, such as lower mutation rates or enhanced DNA repair mechanisms. So rather than contradicting Cope’s rule, our findings refine it.

Larger bodies often evolve, but not as quickly in groups where the burden of cancer is higher. This means that the threat of cancer may have shaped the pace of evolution.

Humans evolved to our current body size relatively rapidly. Based on this, we would expect humans and bats to have similar cancer prevalence, because we evolved at a much, much faster rate. However, it is important to note that our results can’t explain the actual prevalence of cancer in humans. Nor is that an easy statistic to estimate.

Human cancer is a complicated story to unravel, with a plethora of types and many factors affecting its prevalence. For example, many humans not only have access to modern medicine but also varied lifestyles that affect cancer risk. For this reason, we did not include humans in our analysis.

Fighting cancer

Understanding how species naturally evolve cancer defences has important implications for human medicine. The naked mole rat, for example, is studied for its exceptionally low cancer prevalence in the hopes of uncovering new ways to prevent or treat cancer in humans. Only a few cancer cases have ever been observed in captive mole rats, so the exact mechanisms of their cancer resistance remain mostly a mystery.

At the same time, our findings raise new questions. Although birds and mammals that evolved quickly seem to have stronger anti-cancer mechanisms, amphibians and reptiles didn’t show the same pattern. Larger species had higher cancer prevalence regardless of how quickly they evolved. This could be due to differences in their regenerative abilities. Some amphibians, like salamanders, can regenerate entire limbs—a process that involves lots of cell division, which cancer could exploit.

Putting cancer into an evolutionary context allowed us to reveal that its prevalence does increase with body size. Studying this evolutionary arms race may unlock new insights into how nature fights cancer—and how we might do the same.

Joanna Baker, Postdoctoral Researcher in Evolutionary Biology, University of Reading and George Butler, Career Development Fellow in Cancer Evolution, UCL. This article is republished from The Conversation under a Creative Commons license. Read the original article.

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The X-37B spaceplane lands after helping pave the way for “maneuver warfare”

Boeing, military space, Science, Space, Vandenberg space force base, x-37b spaceplane / Kelly Newman / March 8, 2025

On this mission, military officials said the X-37B tested “space domain awareness technology experiments” that aim to improve the Space Force’s knowledge of the space environment. Defense officials consider the space domain—like land, sea, and air—a contested environment that could become a battlefield in future conflicts.

Last month, the Space Force released the first image of Earth from an X-37B in space. This image was captured in 2024 as the spacecraft flew in its high-altitude orbit, and shows a portion of the X-37B’s power-generating solar array. Credit: US Space Force

The Space Force hasn’t announced plans for the next X-37B mission. Typically, the next X-37B flight has launched within a year of the prior mission’s landing. So far, all of the X-37B flights have launched from Florida, with landings at Vandenberg and at NASA’s Kennedy Space Center, where Boeing and the Space Force refurbish the spaceplanes between missions.

The aerobraking maneuvers demonstrated by the X-37B could find applications on future operational military satellites, according to Gen. Stephen Whiting, head of US Space Command.

“The X-37 is a test and experimentation platform, but that aerobraking maneuver allowed it to bridge multiple orbital regimes, and we think this is exactly the kind of maneuverability we’d like to see in future systems, which will unlock a whole new series of operational concepts,” Whiting said in December at the Space Force Association’s Spacepower Conference.

Space Command’s “astrographic” area of responsibility (AOR) starts at the top of Earth’s atmosphere and extends to the Moon and beyond.

“An irony of the space domain is that everything in our AOR is in motion, but rarely do we use maneuver as a way to gain positional advantage,” Whiting said. “We believe at US Space Command it is vital, given the threats we now see in novel orbits that are hard for us to get to, as well as the fact that the Chinese have been testing on-orbit refueling capability, that we need some kind of sustained space maneuver.”

Improvements in maneuverability would have benefits in surveilling an adversary’s satellites, as well as in defensive and offensive combat operations in orbit.

The Space Force could attain the capability for sustained maneuvers—known in some quarters as dynamic space operations—in several ways. One is to utilize in-orbit refueling that allows satellites to “maneuver without regret,” and another is to pursue more fuel-efficient means of changing orbits, such as aerobraking or solar-electric propulsion.

Then, Whiting said Space Command could transform how it operates by employing “maneuver warfare” as the Army, Navy and Air Force do. “We think we need to move toward a joint function of true maneuver advantage in space.”

The X-37B spaceplane lands after helping pave the way for “maneuver warfare” Read More »

Measles outbreak hits 208 cases as federal response goes off the rails

autism, health, Infectious disease, measles, MMR, New Mexico, Science, texas, vaccination / Beth Washington / March 8, 2025

Vitamin A is a fat-soluble vitamin that stays in the body. Taking too much over longer periods can cause vomiting, headache, fatigue, joint and bone pain, blurry vision, and skin and hair problems. Further, it can lead to dangerously high pressure inside the skull that pushes on the brain, as well as liver damage, confusion, coma, and other problems, according to the American Academy of Pediatrics.

Nevertheless, in an interview with Fox News this week, Kennedy endorsed an unconventional regimen of a steroid, an antibiotic and cod liver oil, praising two Texas doctors for giving it to patients. One of the doctors Kennedy championed was disciplined by the state medical board in 2003 for “unusual use of risk-filled medications,” according to a report by CNN.

In a yet more worrying sign, Reuters reported Friday afternoon that the CDC is planning to conduct a large study on whether the MMR vaccine is linked to autism. This taxpayer-funded effort would occur despite the fact that decades of research and numerous high-quality studies have already been conducted—and they have consistently disproven or found no connection between the vaccine and autism.

The agency’s move is exactly what Democratic senators feared when Kennedy was confirmed as the country’s top health official. In Senate hearings, Kennedy refused to say that vaccines do not cause autism. Democratic senators quickly warned that his anti-vaccine stance could not only move the country backward in the fight against vaccine-preventable diseases, but also hold back autism research aimed at finding the real cause(s) as well as better treatments.

“When you continue to sow doubt about settled science it makes it impossible for us to move forward,” Senator Maggie Hassan (D-N.H.) said in a Senate hearing. “It’s the relitigating and rehashing … it freezes us in place.”

Measles outbreak hits 208 cases as federal response goes off the rails Read More »

The Starship program hits another speed bump with second consecutive failure

Commercial space, elon musk, launch, NASA, Science, Space, spacex, starship, starship flight 8 / DJ Henderson / March 7, 2025

The flight flight plan going into Thursday’s mission called for sending Starship on a journey halfway around the world from Texas, culminating in a controlled reentry over the Indian Ocean before splashing down northwest of Australia.

The test flight was supposed to be a do-over of the previous Starship flight on January 16, when the rocket’s upper stage—itself known as Starship, or ship—succumbed to fires fueled by leaking propellants in its engine bay. Engineers determined the most likely cause of the propellant leak was a harmonic response several times stronger than predicted, suggesting the vibrations during the ship’s climb into space were in resonance with the vehicle’s natural frequency. This would have intensified the vibrations beyond the levels engineers expected.

The Super Heavy booster returned to Starbase in Texas to be caught back at the launch pad. Credit: SpaceX

Engineers test-fired the Starship vehicle for this week’s test flight earlier this month, validating changes to the ship’s fuel feed lines leading its six Raptor engines, adjustments to propellant temperatures, and a new operating thrust.

But engineers missed something. On Thursday, the Raptor engines began shutting down on Starship about eight minutes into the flight, and the rocket started tumbling 90 miles (146 kilometers) over the southeastern Gulf of Mexico. SpaceX ground controllers lost all contact with the rocket about nine-and-a-half minutes after liftoff.

“Prior to the end of the ascent burn, an energetic event in the aft portion of Starship resulted in the loss of several Raptor engines,” SpaceX wrote on X. “This in turn led to a loss of attitude control and ultimately a loss of communications with Starship.”

Just like in January, residents and tourists across the Florida peninsula, the Bahamas, and the Turks and Caicos Islands shared videos of fiery debris trails appearing in the twilight sky. Air traffic controllers diverted or delayed dozens of commercial airline flights flying through the debris footprint, just as they did in response to the January incident.

There were no immediate reports Thursday of any Starship wreckage falling over populated areas. In January, residents in the Turks and Caicos Islands recovered small debris fragments, including one piece that caused minor damage when it struck a car. The debris field from Thursday’s failed flight appeared to fall west of the areas where debris fell after Starship Flight 7.

A spokesperson for the Federal Aviation Administration said the regulatory agency will require SpaceX perform an investigation into Thursday’s Starship failure.

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When Europe needed it most, the Ariane 6 rocket finally delivered

ariane 6, Arianespace, Europe, france, launch, military space, Science, Space / Mike M. / March 7, 2025

“For this sovereignty, we must yield to the temptation of preferring SpaceX.”

Europe’s second Ariane 6 rocket lifted off from the Guiana Space Center on Thursday with a French military spy satellite. Credit: ESA-CNES-Arianespace-P. Piron

Europe’s Ariane 6 rocket lifted off Thursday from French Guiana and deployed a high-resolution reconnaissance satellite into orbit for the French military, notching a success on its first operational flight.

The 184-foot-tall (56-meter) rocket lifted off from Kourou, French Guiana, at 11: 24 am EST (16: 24 UTC). Twin solid-fueled boosters and a hydrogen-fueled core stage engine powered the Ariane 6 through thick clouds on an arcing trajectory north from the spaceport on South America’s northeastern coast.

The rocket shed its strap-on boosters a little more than two minutes into the flight, then jettisoned its core stage nearly eight minutes after liftoff. The spent rocket parts fell into the Atlantic Ocean. The upper stage’s Vinci engine ignited two times to reach a nearly circular polar orbit about 500 miles (800 kilometers) above the Earth. A little more than an hour after launch, the Ariane 6 upper stage deployed CSO-3, a sharp-eyed French military spy satellite, to begin a mission providing optical surveillance imagery to French intelligence agencies and military forces.

“This is an absolute pleasure for me today to announce that Ariane 6 has successfully placed into orbit the CSO-3 satellite,” said David Cavaillolès, who took over in January as CEO of Arianespace, the Ariane 6’s commercial operator. “Today, here in Kourou, we can say that thanks to Ariane 6, Europe and France have their own autonomous access to space back, and this is great news.”

This was the second flight of Europe’s new Ariane 6 rocket, following a mostly successful debut launch last July. The first test flight of the unproven Ariane 6 carried a batch of small, relatively inexpensive satellites. An Auxiliary Propulsion Unit (APU)—essentially a miniature second engine—on the upper stage shut down in the latter portion of the inaugural Ariane 6 flight, after the rocket reached orbit and released some of its payloads. But the unit malfunctioned before a third burn of the upper stage’s main engine, preventing the Ariane 6 from targeting a controlled reentry into the atmosphere.

The APU has several jobs on an Ariane 6 flight, including maintaining pressure inside the upper stage’s cryogenic propellant tanks, settling propellants before each main engine firing, and making fine adjustments to the rocket’s position in space. The APU appeared to work as designed Thursday, although this launch flew a less demanding profile than the test flight last year.

Is Ariane 6 the solution?

Ariane 6 has been exorbitantly costly and years late, but its first operational success comes at an opportune time for Europe.

Philippe Baptiste, France’s minister for research and higher education, says Ariane 6 is “proof of our space sovereignty,” as many European officials feel they can no longer rely on the United States. Baptiste, an engineer and former head of the French space agency, mentioned “sovereignty” so many times, turning his statement into a drinking game crossed my mind.

“The return of Donald Trump to the White House, with Elon Musk at his side, already has significant consequences on our research partnerships, on our commercial partnerships,” Baptiste said. “Should I mention the uncertainties weighing today on our cooperation with NASA and NOAA, when emblematic programs like the ISS (International Space Station) are being unilaterally questioned by Elon Musk?

“If we want to maintain our independence, ensure our security, and preserve our sovereignty, we must equip ourselves with the means for strategic autonomy, and space is an essential part of this,” he continued.

Philippe Baptiste arrives at a government question session at the Senate in Paris on March 5, 2025. Credit: Magali Cohen/Hans Lucas/AFP via Getty Images

Baptiste’s comments echo remarks from a range of European leaders in recent weeks.

French President Emmanuel Macron said in a televised address Wednesday night that the French were “legitimately worried” about European security after Trump reversed US policy on Ukraine. America’s NATO allies are largely united in their desire to continue supporting Ukraine in its defense against Russia’s invasion, while the Trump administration seeks a ceasefire that would require significant Ukrainian concessions.

“I want to believe that the United States will stay by our side, but we have to be prepared for that not to be the case,” Macron said. “The future of Europe does not have to be decided in Washington or Moscow.”

Friedrich Merz, set to become Germany’s next chancellor, said last month that Europe should strive to “achieve independence” from the United States. “It is clear that the Americans, at least this part of the Americans, this administration, are largely indifferent to the fate of Europe.”

Merz also suggested Germany, France, and the United Kingdom should explore cooperation on a European nuclear deterrent to replace that of the United States, which has committed to protecting European territory from Russian attack for more than 75 years. Macron said the French military, which runs the only nuclear forces in Europe fully independent of the United States, could be used to protect allies elsewhere on the continent.

Access to space is also a strategic imperative for Europe, and it hasn’t come cheap. ESA paid more than $4 billion to develop the Ariane 6 rocket as a cheaper, more capable replacement for the Ariane 5, which retired in 2023. There are still pressing questions about Ariane 6’s cost per launch and whether the rocket will ever be able to meet its price target and compete with SpaceX and other companies in the commercial market.

But European officials have freely admitted the commercial market is secondary on their list of Ariane 6 goals.

European satellite operators stopped launching their payloads on Russian rockets after the invasion of Ukraine in 2022. Now, with Elon Musk inserting himself into European politics, there’s little appetite among European government officials to launch their satellites on SpaceX’s Falcon 9 rocket.

The second Ariane 6 rocket on the launch pad in French Guiana. Credit: ESA–S. Corvaja

The Falcon 9 was the go-to choice for the European Space Agency, the European Union, and several national governments in Europe after they lost access to Russia’s Soyuz rocket and when Europe’s homemade Ariane 6 and Vega rockets faced lengthy delays. ESA launched a $1.5 billion space telescope on a Falcon 9 rocket in 2023, then returned to SpaceX to launch a climate research satellite and an asteroid explorer last year. The European Union paid SpaceX to launch four satellites for its flagship Galileo navigation network.

European space officials weren’t thrilled to do this. ESA was somewhat more accepting of the situation, with the agency’s director general recognizing Europe was suffering from an “acute launcher crisis” two years ago. On the other hand, the EU refused to even acknowledge SpaceX’s role in delivering Galileo satellites to orbit in the text of a post-launch press release.

“For this sovereignty, we must yield to the temptation of preferring SpaceX or another competitor that may seem trendier, more reliable, or cheaper,” Baptiste said. “We did not yield for CSO-3, and we will not yield in the future. We cannot yield because doing so would mean closing the door to space for good, and there would be no turning back. This is why the first commercial launch of Ariane 6 is not just a technical and one-off success. It marks a new milestone, essential in the choice of European space independence and sovereignty.”

Two flights into its career, Ariane 6 seems to offer a technical solution for Europe’s needs. But at what cost? Arianespace hasn’t publicly disclosed the cost for an Ariane 6 launch, although it’s likely somewhere in the range of 80 million to 100 million euros, about 40 percent lower than the cost of an Ariane 5. This is about 50 percent more than SpaceX’s list price for a dedicated Falcon 9 launch.

A new wave of European startups should soon begin launching small rockets to gain a foothold in the continent’s launch industry. These include Isar Aerospace, which could launch its first Spectrum rocket in a matter of weeks. These companies have the potential to offer Europe an option for cheaper rides to space, but the startups won’t have a rocket in the class of Ariane 6 until at least the 2030s.

Until then, at least, European governments will have to pay more to guarantee autonomous access to space.

Stephen Clark is a space reporter at Ars Technica, covering private space companies and the world’s space agencies. Stephen writes about the nexus of technology, science, policy, and business on and off the planet.

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Norovirus vaccine hints at defusing explosive stomach bug in early trial

health, Norovirus, Science, vaccine, vaxart / Beth Washington / March 7, 2025

Phase I study showed vaccine was safe and spurred immune responses in older people.

An electron micrograph of norovirus. Credit: Getty| BSIP

In an early clinical trial, an experimental norovirus vaccine given as a pill produced defensive responses exactly where it counts—in the saliva of older people most vulnerable to the explosive stomach bug.

The results, published this week in Science Translational Medicine, are another step in the long effort to thwart the gruesome germ, which finds a way to violently hollow out innards wherever people go—from restaurants to natural wonders and even the high seas. It’s a robust, extremely infectious virus that spreads via the nauseating fecal-oral route. Infected people spew billions of virus particles in their vomit and diarrhea, and shedding can last weeks. The particles aren’t easily killed by hand sanitizers and can linger on surfaces for up to two weeks. Exposure to as few as 10 virus particles can spark an infection. According to the Centers for Disease Control and Prevention, norovirus causes an average of between 19 and 21 million cases of acute gastroenteritis in the US every year, leading to 109,000 hospitalizations and 900 deaths. This racks up an economic burden estimated to be $2 billion to $10.6 billion.

Vaccine design

For most, the gut-busting bug is miserable but usually over in a few days. But older people—especially those with underlying medical conditions—are vulnerable to severe outcomes. About 90 percent of people who die from a norovirus infection are people age 65 or older who live in long-term care facilities.

For this reason, researchers have aimed to design a vaccine that’s sure to be effective in older people, who typically have weaker immune responses just from the aging process. But, of course, this makes the already daunting task of developing a vaccine yet harder—and norovirus poses some specific challenges. For one, there aren’t a lot of good laboratory models and animal systems to run norovirus experiments or test candidate drugs. For example, healthy mice infected with a mouse version of norovirus don’t develop any symptoms (lucky critters). Then there’s the fact that norovirus isn’t one virus; it’s many. There are 49 different genotypes of norovirus, which have been categorized into 10 “genogroups.” It’s unclear if protection against one genotype or genogroup will help protect against the others, and if so, by how much.

Currently, there are several norovirus vaccines in the works, at various stages with various designs. The one published this week is being developed by a San Francisco-based company called Vaxart and uses a proprietary oral delivery system. The pill includes a deactivated virus particle (an adenovirus), which can’t replicate in people but can deliver the genetic blueprints of two molecules into cells lining our intestines. One of the genetic blueprints it delivers tells the intestinal cells how to manufacture a protein found on the outside of norovirus particles, called VP.1. Once manufactured in the intestines, VP.1 can train the immune system to identify invading norovirus particles and attack them. The other genetic code included in the vaccine is for what’s called an “adjuvant,” which is basically a booster molecule that helps rev up immune responses.

While several other vaccines in the works are delivered by injections, producing systemic responses, the idea of the pill is to build up immune responses to norovirus directly where it invades and attacks—the mucosal lining of the digestive tract, including the mouth and intestines. There is some preliminary data suggesting that having antibodies against norovirus in saliva correlates with protection from the virus.

Good news

Vaxart has previously published Phase I trial data showing that its pill is safe and well-tolerated in healthy adults ages 18 to 49. The study, published in 2018, also indicated that the pill generated “substantial” systemic and mucosal antibodies against norovirus.

For the new study, Vaxart did a repeat Phase I trial with 65 older people—ages 55 to 80, broken into groups of 55 to 65, and 66 to 80. The participants were randomly assigned to get either a placebo (22) or a low (16), medium (16), or high (11) dose of the vaccine VXA-G1.1-NN, which targets one genotype of norovirus. Again, the vaccine was safe and well-tolerated. There were no serious side effects. The most common side effects were headache and fatigue, which were reported at about the same rates among the placebo and vaccinated groups.

Further, detailed examination of the participants’ immune responses showed not only systemic response, but responses in distant mucus membranes. In the blood, two types of antibodies (IgA and IgG) increased by several fold after vaccination compared with the placebo group. The group with the largest responses was the one that received the high dose.

A test that acts as a surrogate for neutralizing antibody responses to norovirus indicated that the antibodies spurred by the vaccine could block the virus. Additional tests found that cellular immune responses were also activated and that the systemic responses result in protection in places far from the intestines—namely the mouth and nose. Saliva tests and nasal swabs found significant jumps in secreted IgA against norovirus.

Immune responses were strongest in the first two months after vaccination and diminished over time, but some persisted for nearly seven months. When the scientists looked at differences between the two age groups (55–65 and 65–80), they didn’t see significant differences, suggesting the vaccine was equally effective in the older group.

Overall, the scientists at Vaxart concluded that the vaccine “has the potential to inhibit infection, viral shedding, and transmission.”

“Overall, VXA-G1.1-NN administration in older adults led to robust and durable immunogenicity detected both in circulation and multiple mucosal sites, an exciting outcome considering that diminished cellular and mucosal immunity are typical in older populations,” they wrote.

Not so good news

The outlook isn’t entirely rosy, though—there is some bad news. While immune responses rose in statistically significant measures during this small early-stage trial, it’s unclear if that equates to real-life protection. And there’s some good reason to be wary. In 2023, Vaxart released results of a challenge study, in which 141 brave souls (76 vaccinated and 65 given a placebo) were deliberately exposed to norovirus to see if the vaccine was protective. The results were weak: 53 placebo-group members (81.5 percent) became infected with norovirus, as determined by a PCR test looking for genetic evidence of the virus in their stool—and so did 76 vaccinated people (60 percent). That worked out to the vaccine offering only a 29 percent lower relative risk of getting infected. Looking at whether infected people developed symptoms of acute gastroenteritis, the vaccine had a protective efficacy of about 21 percent: 34 vaccinated people (48 percent) versus 37 placebo-group members (57 percent) developed symptoms.

While the study was a disappointment, Vaxart wasn’t ready to give up, arguing that the challenge study used large-dose exposures that people wouldn’t encounter in the real world.

“We use lots of copies of virus to ensure a high infection rate. In nature, 10 to 15 copies of virus is generally enough to give certain susceptible individuals disease,” James Cummings, chief medical officer at Vaxart, said in an investor call reported by Fierce Biotech at the time. “Field efficacy generally goes up, because the amount of inoculum that is causing disease that will be seen in the field is far lower than what is seen in the challenge study. My projection is that we would see an improvement in the decrease of [acute gastroenteritis] with our vaccine.”

Even a slight boost in efficacy could make the vaccine seem worthwhile. A 2012 modeling study suggested that even a vaccine with 50 percent efficacy could avert up to 2.2 million cases and save up to $2 billion over four years.

For now, we’ll have to wait to see what future trial data shows. And Vaxart’s vaccine isn’t the only one in the pipeline, nor is it the furthest along. Moderna has a norovirus vaccine in a Phase 3 trial, which is a larger study that will look at efficacy. But, while the trial is just beginning, Moderna noted in a financial update in February that the trial has been put on hold by the Food and Drug Administration due to a possible neurological side effect in one participant.

“The trial is currently on FDA clinical hold following a single adverse event report of a case of Guillain-Barré syndrome, which is currently under investigation,” Moderna reported. “The Company does not expect an impact on the study’s efficacy readout timeline as enrollment in the Northern Hemisphere has already been completed. The timing of the Phase 3 readout will be dependent on case accruals.”

Beth is Ars Technica’s Senior Health Reporter. Beth has a Ph.D. in microbiology from the University of North Carolina at Chapel Hill and attended the Science Communication program at the University of California, Santa Cruz. She specializes in covering infectious diseases, public health, and microbes.

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“Wooly mice” a test run for mammoth gene editing

Biology, de-extinction, fur, gene editing, Genetics, mammoths, Mice, Science / Kelly Newman / March 5, 2025

On Tuesday, the team behind the plan to bring mammoth-like animals back to the tundra announced the creation of what it is calling wooly mice, which have long fur reminiscent of the woolly mammoth. The long fur was created through the simultaneous editing of as many as seven genes, all with a known connection to hair growth, color, and/or texture.

But don’t think that this is a sort of mouse-mammoth hybrid. Most of the genetic changes were first identified in mice, not mammoths. So, the focus is on the fact that the team could do simultaneous editing of multiple genes—something that they’ll need to be able to do to get a considerable number of mammoth-like changes into the elephant genome.

Of mice and mammoths

The team at Colossal Biosciences has started a number of de-extinction projects, including the dodo and thylacine, but its flagship project is the mammoth. In all of these cases, the plan is to take stem cells from a closely related species that has not gone extinct, and edit a series of changes based on the corresponding genomes of the deceased species. In the case of the mammoth, that means the elephant.

But the elephant poses a large number of challenges, as the draft paper that describes the new mice acknowledges. “The 22-month gestation period of elephants and their extended reproductive timeline make rapid experimental assessment impractical,” the researchers acknowledge. “Further, ethical considerations regarding the experimental manipulation of elephants, an endangered species with complex social structures and high cognitive capabilities, necessitate alternative approaches for functional testing.”

So, they turned to a species that has been used for genetic experiments for over a century: the mouse. We can do all sorts of genetic manipulations in mice, and have ways of using embryonic stem cells to get those manipulations passed on to a new generation of mice.

For testing purposes, the mouse also has a very significant advantage: mutations that change its fur are easy to spot. Over the century-plus that we’ve been using mice for research, people have noticed and observed a huge variety of mutations that affect their fur, altering color, texture, and length. In many of these cases, the changes in the DNA that cause these changes have been identified.

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Do these dual images say anything about your personality?

Big Five, human perception, illusion, Personality types, psychology, Science / Beth Washington / March 5, 2025

There’s little that Internet denizens love more than a snazzy personality test—cat videos, maybe, or perpetual outrage. One trend that has gained popularity over the last several years is personality quizzes based on so-called ambiguous images—in which one sees either a young girl or an old man, for instance, or a skull or a little girl. It’s possible to perceive both images by shifting one’s perspective, but it’s the image one sees first that is said to indicate specific personality traits. According to one such quiz, seeing the young girl first means you are optimistic and a bit impulsive, while seeing the old man first would mean one is honest, faithful, and goal-oriented.

But is there any actual science to back up the current fad? There is not, according to a paper published in the journal PeerJ, whose authors declare these kinds of personality quizzes to be a new kind of psychological myth. That said, they did find a couple of intriguing, statistically significant correlations they believe warrant further research.

In 1892, a German humor magazine published the earliest known version of the “rabbit-duck illusion,” in which one can see either a rabbit or a duck, depending on one’s perspective—i.e., multistable perception. There have been many more such images produced since then, all of which create ambiguity by exploiting certain peculiarities of the human visual system, such as playing with illusory contours and how we perceive edges.

Such images have long fascinated scientists and philosophers because they seem to represent different ways of seeing. So naturally there is a substantial body of research drawing parallels between such images and various sociological, biological, or psychological characteristics.

For instance, a 2010 study examined BBC archival data on the duck-rabbit illusion from the 1950s and found that men see the duck more often than women, while older people were more likely to see the rabbit. A 2018 study of the “younger-older woman” ambiguous image asked participants to estimate the age of the woman they saw in the image. Older participants over 30 gave higher estimates than younger ones. This was confirmed by a 2021 study, although that study also found no correlation between participants’ age and whether they were more likely to see the older or younger woman in the image.

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These hot oil droplets can bounce off any surface

bouncing droplets, inverse leidenfrost effect, Leidenfrost effect, Physics, Science / Mike M. / March 4, 2025

The Hong Kong physicists were interested in hot droplets striking cold surfaces. Prior research showed there was less of a bouncing effect in such cases involving heated water droplets, with the droplets sticking to the surface instead thanks to various factors such as reduced droplet surface tension. The Hong Kong team discovered they could achieve enhanced bouncing by using hot droplets of less volatile liquids—namely, n-hexadecane, soybean oil, and silicon oil, which have lower saturation pressures compared to water.

Follow the bouncing droplet

The researchers tested these hot droplets (as well as burning and normal temperature droplets) on various solid, cold surfaces, including scratched glass, smooth glass, acrylic surfaces, surfaces with liquid-repellant coatings from candle soot, and surfaces coated with nanoparticles with varying “wettability” (i.e., how well particles stick to the surface). They captured the droplet behavior with both high-speed and thermal cameras, augmented with computer modeling.

The room-temperature droplets stuck to all the surfaces as expected, but the hot and burning droplets bounced. The team found that the bottom of a hot droplet cools faster than the top as it approaches a room-temperature surface, which causes hotter liquid within the droplet to flow from the edges toward the bottom. The air that is dragged to the bottom with it forms a thin cushion there and prevents the droplet from making contact with the surface, bouncing off instead. They dubbed the behavior “self-lubricated bouncing.”

“It is now clear that droplet-bouncing strategies are not isolated to engineering the substrate and that the thermophysical properties of droplets themselves are critical,” Jonathan B. Boreyko of Virginia Tech, who was not involved in the research, wrote in an accompanying commentary.

Future applications include improving the combustion efficiency of fuels or developing better fire-retardant coatings. “If burning droplets can’t stick to surfaces, they won’t be able to ignite new materials and allow fires to propagate,” co-author Pingan Zhu said. “Our study could help protect flammable materials like textiles from burning droplets. Confining fires to a smaller area and slowing their spread could give firefighters more time to put them out.”

DOI: Newton, 2025. 10.1016/j.newton.2025.100014 (About DOIs).

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