Science – Page 15

We probably inherited our joints from… a fish

Biology, developmental biology, evolution, joints, paleontology, Science, synovial joints / Mike M. / March 23, 2025

What do we have in common with fish, besides being vertebrates? The types of joints we (and most vertebrates) share most likely originated from the same common ancestor. But it’s not a feature that we share with all vertebrates.

Humans, other land vertebrates, and jawed fish have synovial joints. The lubricated cavity within these joints makes them more mobile and stable because it allows for bones or cartilage to slide against each other without friction, which facilitates movement.

The origin of these joints was uncertain. Now, biologist Neelima Sharma of the University of Chicago and her colleagues have taken a look at which fish form this type of joint. Synovial joints are known to be present in jawed but not jawless fish. This left the question of whether they are just a feature of bony skeletons in general or if they are also found in fish with cartilaginous skeletons, such as sharks and skates (there are no land animals with cartilaginous skeletons).

As Sharma and her team found, cartilaginous fish with jaws, such as the skate embryos they studied, do develop these joints, while jawless fish, such as lampreys and hagfish, lack them.

So what could this mean? If jawed fish have synovial joints in common with all jawed vertebrates, including us, it must have evolved in our shared ancestor.

Something fishy in our past

While the common ancestor of vertebrates with synovial joints is still a mystery, the oldest specimen with evidence of these joints is Bothriolepis canadensis, a fish that lived about 387 to 360 million years ago during the Middle to Late Devonian period.

When using CT scanning to study a Bothriolepis fossil, Sharma observed a joint cavity between the shoulder and pectoral fin. Whether the cavity was filled with synovial fluid or cartilage is impossible to tell, but either way, she thinks it appears to have functioned like a synovial joint would. Fossils of early jawless fish, in contrast, lack any signs of synovial joints.

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How the language of job postings can attract rule-bending narcissists

hiring, narcississm, psychology, Science, Social science, syndication / Beth Washington / March 23, 2025

Why it matters

Companies write job postings carefully in hopes of attracting the ideal candidate. However, they may unknowingly attract and select narcissistic candidates whose goals and ethics might not align with a company’s values or long-term success. Research shows that narcissistic employees are more likely to behave unethically, potentially leading to legal consequences.

While narcissistic traits can lead to negative outcomes, we aren’t saying that companies should avoid attracting narcissistic applicants altogether. Consider a company hiring a salesperson. A firm can benefit from a salesperson who is persuasive, who “thinks outside the box,” and who is “results-oriented.” In contrast, a company hiring an accountant or compliance officer would likely benefit from someone who “thinks methodically” and “communicates in a straightforward and accurate manner.”

Bending the rules is of particular concern in accounting. A significant amount of research examines how accounting managers sometimes bend rules or massage the numbers to achieve earnings targets. This “earnings management” can misrepresent the company’s true financial position.

In fact, my co-author Nick Seybert is currently working on a paper whose data suggests rule-bender language in accounting job postings predicts rule-bending in financial reporting.

Our current findings shed light on the importance of carefully crafting job posting language. Recruiting professionals may instinctively use rule-bender language to try to attract someone who seems like a good fit. If companies are concerned about hiring narcissists, they may want to clearly communicate their ethical values and needs while crafting a job posting, or avoid rule-bender language entirely.

What still isn’t known

While we find that professional recruiters are using language that attracts narcissists, it is unclear whether this is intentional.

Additionally, we are unsure what really drives rule-bending in a company. Rule-bending could happen due to attracting and hiring more narcissistic candidates, or it could be because of a company’s culture—or a combination of both.

The Research Brief is a short take on interesting academic work.

Jonathan Gay is Assistant Professor of Accountancy at the University of Mississippi.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Measles arrives in Kansas, spreads quickly in undervaccinated counties

health, Infectious disease, kansas, measles, MMR, outbreak, Science, texas, unvaccinated, vaccinated, virus / DJ Henderson / March 22, 2025

On Thursday, the county on the northern border of Stevens, Grant County, also reported three confirmed cases, which were also linked to the first case in Stevens. Grant County is in a much better position to handle the outbreak than its neighbors; its one school district, Ulysses, reported 100 percent vaccination coverage for kindergartners in the 2023–2024 school year.

Outbreak risk

So far, details about the fast-rising cases are scant. The Kansas Department of Health and Environment (KDHE) has not published another press release about the cases since March 13. Ars Technica reached out to KDHE for more information but did not hear back before this story’s publication.

The outlet KWCH 12 News out of Wichita published a story Thursday, when there were just six cases reported in just Grant and Stevens Counties, saying that all six were in unvaccinated people and that no one had been hospitalized. On Friday, KWCH updated the story to note that the case count had increased to 10 and that the health department now considers the situation an outbreak.

Measles is an extremely infectious virus that can linger in airspace and on surfaces for up to two hours after an infected person has been in an area. Among unvaccinated people exposed to the virus, 90 percent will become infected.

Vaccination rates have slipped nationwide, creating pockets that have lost herd immunity and are vulnerable to fast-spreading, difficult-to-stop outbreaks. In the past, strong vaccination rates prevented such spread, and in 2000, the virus was declared eliminated, meaning there was no continuous spread of the virus over a 12-month period. Experts now fear that the US will lose its elimination status, meaning measles will once again be considered endemic to the country.

So far this year, the Centers for Disease Control and Prevention has documented 378 measles cases as of Thursday, March 20. That figure is already out of date.

On Friday, the Texas health department reported 309 cases in its ongoing outbreak. Forty people have been hospitalized, and one unvaccinated child with no underlying medical conditions has died. The outbreak has spilled over to New Mexico and Oklahoma. In New Mexico, officials reported Friday that the case count has risen to 42 cases, with two hospitalizations and one death in an unvaccinated adult. In Oklahoma, the case count stands at four.

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“Infantile amnesia” occurs despite babies showing memory activity

Biology, infantile amnesia, memory, neurobiology, Science / Mike M. / March 22, 2025

For many of us, memories of our childhood have become a bit hazy, if not vanishing entirely. But nobody really remembers much before the age of 4, because nearly all humans experience what’s termed “infantile amnesia,” in which memories that might have formed before that age seemingly vanish as we move through adolescence. And it’s not just us; the phenomenon appears to occur in a number of our fellow mammals.

The simplest explanation for this would be that the systems that form long-term memories are simply immature and don’t start working effectively until children hit the age of 4. But a recent animal experiment suggests that the situation in mice is more complex: the memories are there, they’re just not normally accessible, although they can be re-activated. Now, a study that put human infants in an MRI tube suggests that memory activity starts by the age of 1, suggesting that the results in mice may apply to us.

Less than total recall

Mice are one of the species that we know experience infantile amnesia. And, thanks to over a century of research on mice, we have some sophisticated genetic tools that allow us to explore what’s actually involved in the apparent absence of the animals’ earliest memories.

A paper that came out last year describes a series of experiments that start by having very young mice learn to associate seeing a light come on with receiving a mild shock. If nothing else is done with those mice, that association will apparently be forgotten later in life due to infantile amnesia.

But in this case, the researchers could do something. Neural activity normally results in the activation of a set of genes. In these mice, the researchers engineered it so one of the genes that gets activated encodes a protein that can modify DNA. When this protein is made, it results in permanent changes to a second gene that was inserted in the animal’s DNA. Once activated through this process, the gene leads to the production of a light-activated ion channel.

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Hints grow stronger that dark energy changes over time

cosmology, dark energy, Dark Energy Spectroscopic Instrument, Lambda CDM, Physics, Science, the standard model / DJ Henderson / March 20, 2025

In its earliest days, the Universe was a hot, dense soup of subatomic particles, including hydrogen and helium nuclei, aka baryons. Tiny fluctuations created a rippling pattern through that early ionized plasma, which froze into a three-dimensional place as the Universe expanded and cooled. Those ripples, or bubbles, are known as baryon acoustic oscillations (BAO). It’s possible to use BAOs as a kind of cosmic ruler to investigate the effects of dark energy over the history of the Universe.

DESI is a state-of-the-art instrument and can capture light from up to 5,000 celestial objects simultaneously. — DESI is a state-of-the-art instrument that can capture light from up to 5,000 celestial objects simultaneously.

That’s what DESI was designed to do: take precise measurements of the apparent size of these bubbles (both near and far) by determining the distances to galaxies and quasars over 11 billion years. That data can then be sliced into chunks to determine how fast the Universe was expanding at each point of time in the past, the better to model how dark energy was affecting that expansion.

An upward trend

Last year’s results were based on analysis of a full year’s worth of data taken from seven different slices of cosmic time and include 450,000 quasars, the largest ever collected, with a record-setting precision of the most distant epoch (between 8 to 11 billion years back) of 0.82 percent. While there was basic agreement with the Lamba CDM model, when those first-year results were combined with data from other studies (involving the cosmic microwave background radiation and Type Ia supernovae), some subtle differences cropped up.

Essentially, those differences suggested that the dark energy might be getting weaker. In terms of confidence, the results amounted to a 2.6-sigma level for the DESI’s data combined with CMB datasets. When adding the supernovae data, those numbers grew to 2.5-sigma, 3.5-sigma, or 3.9-sigma levels, depending on which particular supernova dataset was used.

It’s important to combine the DESI data with other independent measurements because “we want consistency,” said DESI co-spokesperson Will Percival of the University of Waterloo. “All of the different experiments should give us the same answer to how much matter there is in the Universe at present day, how fast the Universe is expanding. It’s no good if all the experiments agree with the Lambda-CDM model, but then give you different parameters. That just doesn’t work. Just saying it’s consistent to the Lambda-CDM, that’s not enough in itself. It has to be consistent with Lambda-CDM and give you the same parameters for the basic properties of that model.”

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Brains of parrots, unlike songbirds, use human-like vocal control

Biology, brain, brain implants, language, neurobiology, Science, vocal control / 9u50fv / March 20, 2025

Due to past work, we’ve already identified the brain structure that controls the activity of the key vocal organ, the syrinx, located in the bird’s throat. The new study, done by Zetian Yang and Michael Long of New York University, managed to place fine electrodes into this area of the brain in both species and track the activity of neurons there while the birds were awake and going about normal activities. This allowed them to associate neural activity with any vocalizations made by the birds. For the budgerigars, they had an average of over 1,000 calls from each of the four birds carrying the implanted electrodes.

For the zebra finch, neural activity during song production showed a pattern that was based on timing; the same neurons tended to be most active at the same point in the song. You can think of this as a bit like a player piano central organizing principle, timing when different notes should be played. “Different configurations [of neurons] are active at different moments, representing an evolving population ‘barcode,’” as Yang and Long describe this pattern.

That is not at all what was seen with the budgerigars. Here, instead, they saw patterns where the same populations of neurons tended to be active when the bird was producing a similar sound. They broke the warbles down into parts that they characterized on a scale that ranged from harmonic to noisy. They found that the groups of neurons tended to be more active whenever the warble was harmonic, and different groups tended to spike when it got noisy. Those observations led them to identify a third population, which was active whenever the budgerigars produced a low-frequency sound.

In addition, Yang and Long analyzed the pitch of the vocalizations. Only about half of the neurons in the relevant region of the brain were linked to pitch. However, the half that was linked had small groups of neurons that fired during the production of a relatively narrow range of pitches. They could use the activity of as few as five individual neurons and accurately predict the pitch of the vocalizations at the time.

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Even the worst mass extinction had its oases

Biology, Ecology, end-permian, Great Dying, mass extinction, paleontology, refugee, Science / Kelly Newman / March 18, 2025

Some earlier plants might not have made it through the extinction since rock layers from the onset of the End-Permian Mass Extinction showed a decrease in pollen and spores, as well as fewer plant species. Other species were scarce because they had not been as well-preserved as others; the team did not automatically assume the scarcity of a plant that did not fossilize meant it had gone extinct.

While there were plant species that ended up being victims of the Great Dying, analysis of species through spore and pollen told the team that only about 21 percent of them succumbed to extinction.

Life will not be contained

The fossils also revealed the presence of plant species known to grow near lakes, which meant an environment that most likely provided drinking water for land-dwelling animals. Fossilized spores farther from what were once the banks of an ancient lake or the edge of a lakeplain suggest it was surrounded by a forest of gymnospermous trees, such as conifers or ginkgo, and ferns.

Because the researchers found so many spores from plant species known to grow in humid climates, they think the regional climate before the extinction was either humid or sub-humid, with plenty of rain. It was a lush environment that would see dry periods during the mass extinction event, but not be completely devastated.

Despite some species of plants vanishing, those that were found to have survived during and after the extinction mostly belonged to conifers and pteridosperms (now-extinct plants similar to ferns), which showed “a remarkable ability to adapt to drought,” as Liu and his team said in the same study.

The drought turned out to be only temporary. Younger rock layers were found to contain a greater abundance of pollen and spores from species that grew during the extinction event. The types of plants represented suggest a climate that had returned to subhumid and was more habitable.

Fossils of animals found at the site support its role as a haven for life. From the herbivorous Lystrosaurus (not a dinosaur), which looked something like a walrus with legs and a shovel face, to the carnivorous chroniosuchians that resembled giant lizards and fed on insects and small amphibians, the refugium in what is now Xinjiang kept life going.

Both flora and fauna would soon spread across terrestrial environments once again. Life on land flourished only 75,000 years after the End-Permian Mass Extinction, so life really does find a way.

Science Advances, 2025. DOI: 10.1126/sciadv.ads5614

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People in this career are better at seeing through optical illusions

optical illusion, Science, syndication / Kelly Newman / March 18, 2025

A hint came from our previous work comparing mathematical and social scientists’ judgements of illusions (we work in universities, so we sometimes study our colleagues). Social scientists, such as psychologists, see illusions more strongly.

Researchers like us have to take many factors into account. Perhaps this makes us more sensitive to context even in the way we see things. But also, it could be that your visual style affects what you choose to study. One of us (Martin) went to university to study physics, but left with a psychology degree. As it happens, his illusion perception is much stronger than normal.

Training your illusion skills

Despite all these individual differences, researchers have always thought that you have no choice over whether you see the illusion. Our recent research challenges this idea.

Radiologists need to be able to rapidly spot important information in medical scans. Doing this often means they have to ignore surrounding detail.

Radiologists train extensively, so does this make them better at seeing through illusions? We found it does. We studied 44 radiologists, compared to over 100 psychology and medical students.

Below is one of our images. The orange circle on the left is 6% smaller than the one on the right. Most people in the study saw it as larger.

The orange circle on the left is actually smaller Credit: Radoslaw Wincza

Here is another image. Most non-radiologists still saw the left one as bigger. Yet, it is 10% smaller. Most radiologists got this one right.

Does the left orange circle look bigger or smaller to you? Credit: Radoslaw Wincza

It was not until the difference was nearly 18%, as shown in the image below, that most non-radiologists saw through the illusion.

Most people get this one right. Credit: Radoslaw Wincza, The Conversation

Radiologists are not entirely immune to the illusion, but are much less susceptible. We also looked at radiologists just beginning training. Their illusion perception was no better than normal. It seems radiologists’ superior perception is a result of their extensive training.

According to current theories of expertise, this shouldn’t happen. Becoming an expert in chess, for example, makes you better at chess but not anything else. But our findings suggest that becoming an expert in medical image analysis also makes you better at seeing through some optical illusions.

There is plenty left to find out. Perhaps the most intriguing possibility is that training on optical illusions can improve radiologists’ skills at their own work.

So, how can you learn to see through illusions? Simple. Just five years of medical school, then seven more of radiology training and this skill can be yours too.

Martin Doherty, Associate Professor in Psychology, University of East Anglia and Radoslaw Wincza, Lecturer in Behavioural Sciences, University of Central Lancashire. This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Here’s the secret to how Firefly was able to nail its first lunar landing

artemis, clps, Commercial space, Features, Firefly Aerospace, human landing system, moon, NASA, Science, Space / Beth Washington / March 18, 2025

Darkness fell over Mare Crisium, ending a daily dose of dazzling images from the Moon.

Firefly’s X-band communications antenna (left) is marked with the logos of NASA, Firefly Aerospace, and the US flag. Credit: Firefly Aerospace

Firefly Aerospace’s Blue Ghost science station accomplished a lot on the Moon in the last two weeks. Among other things, its instruments drilled into the Moon’s surface, tested an extraterrestrial vacuum cleaner, and showed that future missions could use GPS navigation signals to navigate on the lunar surface.

These are all important achievements, gathering data that could shed light on the Moon’s formation and evolution, demonstrating new ways of collecting samples on other planets, and revealing the remarkable reach of the US military’s GPS satellite network.

But the pièce de résistance for Firefly’s first Moon mission might be the daily dose of imagery that streamed down from the Blue Ghost spacecraft. A suite of cameras recorded the cloud of dust created as the lander’s engine plume blew away the uppermost layer of lunar soil as it touched down March 2 in Mare Crisium, or the Sea of Crises. This location is in a flat basin situated on the upper right quadrant of the side of the Moon always facing the Earth.

Other images from Firefly’s lander showed the craft shooting tethered electrodes out onto the lunar surface, like a baseball outfielder trying to throw out a runner at home plate. Firefly’s cameras also showed the lander’s drill as it began to probe several meters into the Moon’s crust.

The first Blue Ghost mission is part of NASA’s Commercial Lunar Payload Services (CLPS) program established in 2018 to partner with US companies for cargo transportation to the Moon. Firefly is one of 13 companies eligible to compete for CLPS missions, precursors to future astronaut landings on the Moon under NASA’s Artemis program.

Now, Firefly finds itself at the top of the pack of firms seeking to gain a foothold at the Moon.

Blue Ghost landed just after sunrise at Mare Crisium, an event shown in the blow video captured with four cameras mounted on the lander to observe how its engine plume interacted with loose soil on the lunar surface. The information will be useful as NASA plans to land astronauts on the Moon in the coming years.

“Although the data is still preliminary, the 3,000-plus images we captured appear to contain exactly the type of information we were hoping for in order to better understand plume-surface interaction and learn how to accurately model the phenomenon based on the number, size, thrust and configuration of the engines,” said Rob Maddock, project manager for NASA’s SCALPSS experiment.

One of the vehicle’s payloads, named Lunar PlanetVac, dropped from the bottom of the lander and released a blast of gas to blow fine-grained lunar soil into a collection chamber for sieving. Provided by a company named Honeybee Robotics, this device could be used as a cheaper alternative to other sample collection methods, such as robotic arms, on future planetary science missions.

Just over 4 days on the Moon’s surface and #BlueGhost is checking off several science milestones! 8 out of 10 @NASA payloads, including LPV, EDS, NGLR, RAC, RadPC, LuGRE, LISTER, and SCALPSS, have already met their mission objectives with more to come. Lunar PlanetVac for example… pic.twitter.com/i7pOg70qYi

— Firefly Aerospace (@Firefly_Space) March 6, 2025

After two weeks of pioneering work, the Blue Ghost lander fell into darkness Sunday when the Sun sank below the horizon, robbing it of solar power and plunging temperatures below minus 200° Fahrenheit (148°Celcius). The spacecraft’s internal electronics likely won’t survive the two-week-long lunar night.

A precoded message from Blue Ghost marked the moment Sunday afternoon, signaling a transition to “monument mode.”

“Goodnight friends,” Blue Ghost radioed Firefly’s mission control center in Central Texas. “After exchanging our final bits of data, I will hold vigil in this spot in Mare Crisium to watch humanity’s continued journey to the stars. Here, I will outlast your mightiest rivers, your tallest mountains, and perhaps even your species as we know it.”

Blue Ghost’s legacy is now secure as the first fully successful commercial lunar lander. Its two-week mission was perhaps just as remarkable for what didn’t happen as it was for what did. The spacecraft encountered no significant problems on its transit to the Moon, its final descent, or during surface operations.

One of the few surprises of the mission was that the lander got hotter a little sooner than engineers predicted. At lunar noon, when the Sun is highest in the sky, temperatures can soar to 250° F (121° C).

“We started noticing that the lander was getting hotter than we expected, and we couldn’t really figure out why, because it was a little early for lunar noon,” Ray Allensworth, Firefly’s spacecraft program director, told Ars. “So we went back and started evaluating and realized that the crater that we landed next to was actually reflecting a really significant amount of heat. So we went back and we updated our thermal models, incorporated that crater into it, and it matched the environment we were seeing.”

Early Friday morning, the Blue Ghost spacecraft captured the first high-definition views of a total solar eclipse from the Moon. At the same time that skywatchers on Earth were looking up to see the Moon turn an eerie blood red, Firefly’s cameras were looking back at us as the Sun, Earth, and Moon moved into alignment and darkness fell at Mare Crisium.

Diamond ring

The eclipse was a bonus for Firefly. It just happened to occur during the spacecraft’s two-week mission at the Moon, the timing of which was dependent on numerous factors, ranging from the readiness of the Blue Ghost lander to weather conditions at its launch site in Florida.

“We weren’t actually planning to have an eclipse until a few months prior to our launch, when we started evaluating and realizing that an eclipse was happening right before lunar sunset,” Allensworth said. “So luckily, that gave us some time to work some procedures and basically set up what we wanted to take images of, what cameras we wanted to run.”

The extra work paid off. Firefly released an image Friday showing a glint of sunlight reaching around the curvature of the Earth, some 250,000 miles (402,000 kilometers) away. This phenomenon is known as the “diamond ring” and is a subject of pursuit for many eclipse chasers, who travel to far-flung locations for a few minutes of totality.

A “diamond ring” appears around the edge of the Earth, a quarter-million miles from Firefly’s science station on the lunar surface. Credit: Firefly Aerospace

The Blue Ghost spacecraft, named for a species of firefly, took eclipse chasing to new heights. Not only did it see the Earth block the Sun from an unexplored location on the Moon, but the lander fell into shadow for 2 hours and 16 minutes, about 18 times longer than the longest possible total solar eclipse on the Earth.

The eclipse presented challenges for Firefly’s engineers monitoring the mission from Texas. Temperatures at the spacecraft’s airless landing site plummeted as darkness took hold, creating what Allensworth called a “pseudo lunar night.”

“We were seeing those temperatures rapidly start dropping,” Allensworth said Friday. “So it was kind of an interesting game of to play with the hardware to keep everything in its temperature bounds but also still powered on and capturing data.”

Shaping up

Using navigation cameras and autonomous guidance algorithms, the spacecraft detected potential hazards at its original landing site and diverted to a safer location more than 230 feet (70 meters) away, according to Allensworth.

Finally happy with the terrain below, Blue Ghost’s computer sent the command for landing, powered by eight thrusters pulsing in rapid succession to control the craft’s descent rate. The landing was gentler than engineers anticipated, coming down at less than 2.2 mph (1 meter per second).

According to preliminary data, Blue Ghost settled in a location just outside of its 330-foot (100-meter) target landing ellipse, probably due to the last-minute divert maneuvers ordered by the vehicle’s hazard avoidance system.

“It looks like we’re slightly out of it, but it’s really OK,” Allensworth said. “NASA has told us, more than anything, that they want us to make sure we land softly… They seem comfortable where we’re at.”

Firefly originally intended to develop a spacecraft based on the design of Israel’s Beresheet lander, which was the first private mission to attempt a landing on the Moon in 2019. The spacecraft crashed, and Firefly opted to go with a new design more responsive to NASA’s requirements.

“Managing the center of gravity and the mass of the lander is most significant, and that informs a lot of how it physically takes shape,” Allensworth said. “So we did want to keep certain things in mind about that, and that really is what led to the lander being wider, shorter, broader. We have these bigger foot pads on there. All of those things were very intentional to help make the lander as stable and predictable as possible.”

Firefly’s Blue Ghost lander, seen here inside the company’s spacecraft manufacturing facility in Cedar Park, Texas. Credit: Stephen Clark/Ars Technica

These design choices must happen early in a spacecraft’s development. Landing on the Moon comes with numerous complications, including an often-uneven surface and the lack of an atmosphere, rendering parachutes useless. A lander targeting the Moon must navigate itself to a safe landing site without input from the ground.

The Odysseus, or Nova-C, lander built by Intuitive Machines snapped one of its legs and fell over on its side after arriving on the Moon last year. The altimeter on Odysseus failed, causing it to come down with too much horizontal velocity. The lander returned some scientific data from the Moon and qualified as a partial success. The spacecraft couldn’t recharge its batteries after landing on its side, and Odysseus shut down a few days after landing.

The second mission by Intuitive Machines reached the Moon on March 6, but it suffered the same fate. After tipping over, the Athena lander succumbed to low power within hours, preventing it from accomplishing its science mission for NASA.

The landers designed by Intuitive Machines are tall and skinny, towering more than 14 feet (4.3 meters) tall with a width of about 5.2 feet (1.6 meters). The Blue Ghost vehicle is short and squatty in shape—about 6.6 feet tall and 11.5 feet wide (2-by-3.5 meters). Firefly’s approach requires fewer landing legs than Intuitive Machines—four instead of six.

Steve Altemus, co-founder and CEO of Intuitive Machines, defended the design of his company’s lander in a press briefing after the second lunar landing tip-over earlier this month. The Nova-C lander isn’t too top-heavy for a safe landing because most of its cargo attaches to the bottom of the spacecraft, and for now, Altemus said Intuitive Machines is not considering a redesign.

Intuitive Machines stacked its two fuel and oxidizer tanks on top of each other, resulting in a taller vehicle. The Nova-C vehicle uses super-cold methane and liquid oxygen propellants, enabling a fast journey to the Moon over just a few days. The four propellant tanks on Blue Ghost are arranged in a diagonal configuration, with two containing hydrazine fuel and two holding an oxidizer called nitrogen tetroxide. Firefly’s Blue Ghost took about six weeks to travel from launch until landing.

The design trade-off means Firefly’s lander is heavier, with four tanks instead of two, according to Will Coogan, Blue Ghost’s chief engineer at Firefly. By going with a stockier lander design, Firefly needed to install four tanks because the spacecraft’s fuel and oxidizer have different densities. If Firefly went with just two tanks side-by-side, the spacecraft’s center of mass would change continually as it burns propellant during the final descent to the Moon, creating an unnecessary problem for the lander’s guidance, navigation, and control system to overcome.

“You want to avoid that,” Coogan told Ars before Blue Ghost’s launch. “What you can do is you can either get four tanks and have fuel and oxidizer at diagonal angles, and then you’re always centered, or you can stay with two tanks, and you can stack them.”

A camera on Firefly’s Blue Ghost lander captured a view of its shadow after touching down on the Moon just after sunrise on March 2. Earth looms over the horizon. Credit: Firefly Aerospace

The four landing legs on the Blue Ghost vehicle have shock-absorbing feet, with bowl-shaped pads able to bend if the lander comes down on a rock or a slope.

“If we did come in a little bit faster, we needed the legs to be able to take that, so we tested the legs really significantly on the ground,” Allensworth said. “We basically loaded them up on a makeshift weight bench at different angles and slammed it into the ground, slammed it into concrete, slammed it into regular simulant rocks, boulders, at different angles to really characterize what the legs could do.

“It’s actually really funny, because one of the edge cases that we didn’t test is if we came down very lightly, with almost no acceleration,” she said. “And that was the case that the lander landed in. I was joking with our structural engineer that he wasted all his time.”

Proof positive

Firefly delivered 10 NASA-sponsored science and technology demonstration experiments to the lunar surface, operating under contract with NASA’s CLPS program. CLPS builds on the commercial, service-based business model of NASA’s commercial cargo and crew program for transportation to the International Space Station.

NASA officials knew this approach was risky. The last landing on the Moon by a US spacecraft was the last Apollo mission in 1972, and most of the companies involved in CLPS are less than 20 years old, with little experience in deep space missions.

A Pittsburgh company named Astrobotic failed to reach the Moon on its first attempt in January 2024. The next month, Houston-based Intuitive Machines landed its Nova-C spacecraft on the lunar surface, but it tipped over after one of its legs snapped at the moment of touchdown.

Firefly, based in Cedar Park, Texas, was the third company to try a landing. Originally established as a rocket developer, Firefly signed up to be a CLPS provider and won a $101 million contract with NASA in 2021 to transport a government-funded science package to the Moon. NASA’s instruments aboard the Blue Ghost lander cost about $44 million.

The successful landing of Firefly’s Blue Ghost earlier this month buoyed NASA’s expectations for CLPS. “Overall, it’s been a fabulous, wonderful proof positive that the CLPS model does work,” said Brad Bailey, assistant deputy associate administrator for exploration in NASA’s Science Mission Directorate.

NASA has seven more CLPS missions on contract. The next could launch as soon as August when Blue Origin plans to send its first Blue Moon lander to the Moon. NASA has booked two more Blue Ghost missions with Firefly and two more landing attempts with Intuitive Machines, plus one more flight by Astrobotic and one lander from Draper Laboratory.

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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Researchers engineer bacteria to produce plastics

biochemistry, bioengineering, Biology, chemistry, plastics, Science / Shannon Garcia / March 18, 2025

Image of a series of chemical reactions, with enzymes driving each step forward. — One of the enzymes used in this system takes an amino acid (left) and links it to Coenzyme A. The second takes these items and links them into a polymer. Credit: Chae et. al.

Normally, PHA synthase forms links between molecules that run through an oxygen atom. But it’s also possible to form a related chemical link that instead runs through a nitrogen atom, like those found on amino acids. There were no known enzymes, however, that catalyze these reactions. So, the researchers decided to test whether any existing enzymes could be induced to do something they don’t normally do.

The researchers started with an enzyme from Clostridium that links chemicals to Coenzyme A that has a reputation for not being picky about the chemicals it interacts with. This worked reasonably well at linking amino acids to Coenzyme A. For linking the amino acids together, they used an enzyme from Pseudomonas that had four different mutations that expanded the range of molecules it would use as reaction materials. Used in a test tube, the system worked: Amino acids were linked together in a polymer.

The question was whether it would work in cells. Unfortunately, one of the two enzymes turns out to be mildly toxic to E. coli, slowing its growth. So, the researchers evolved a strain of E. coli that could tolerate the protein. With both of these two proteins, the cells produced small amounts of an amino acid polymer. If they added an excess of an amino acid to the media the cells were growing in, the polymer would be biased toward incorporating that amino acid.

Boosting polymer production

However, the yield of the polymer by weight of bacteria was fairly low. “It was reasoned that these [amino acids] might be more efficiently incorporated into the polymer if generated within the cells from a suitable carbon source,” the researchers write. So, the researchers put in extra copies of the genes needed to produce one specific amino acid (lysine). That worked, producing more polymer, with a higher percentage of the polymer being lysine.

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Small charges in water spray can trigger the formation of key biochemicals

biochemistry, Biology, chemistry, origin of life, Physics, Science / Beth Washington / March 16, 2025

Once his team nailed how droplets become electrically charged and how the micro-lightning phenomenon works, they recreated the Miller-Urey experiment. Only without the spark plugs.

Ingredients of life

After micro-lightnings started jumping between droplets in a mixture of gases similar to that used by Miller and Urey, the team examined their chemical composition with a mass spectrometer. They confirmed glycine, uracil, urea, cyanoethylene, and lots of other chemical compounds were made. “Micro-lightnings made all organic molecules observed previously in the Miller-Urey experiment without any external voltage applied,” Zare claims.

But does it really bring us any closer to explaining the beginnings of life? After all, Miller and Urey already demonstrated those molecules could be produced by electrical discharges in a primordial Earth’s atmosphere—does it matter all that much where those discharges came from? Zare argues that it does.

“Lightning is intermittent, so it would be hard for these molecules to concentrate. But if you look at waves crashing into rocks, you can think the spray would easily go into the crevices in these rocks,” Zare suggests. He suggests that the water in these crevices would evaporate, new spray would enter and evaporate again and again. The cyclic drying would allow the chemical precursors to build into more complex molecules. “When you go through such a dry cycle, it causes polymerization, which is how you make DNA,” Zare argues. Since sources of spray were likely common on the early Earth, Zare thinks this process could produce far more organic chemicals than potential alternatives like lightning strikes, hydrothermal vents, or impacting comets.

But even if micro-lightning really produced the basic building blocks of life on Earth, we’re still not sure how those combined into living organisms. “We did not make life. We just demonstrated a possible mechanism that gives us some chemical compounds you find in life,” Zare says. “It’s very important to have a lot of humility with this stuff.”

Science Advances, 2025. DOI: 10.1126/sciadv.adt8979

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A “biohybrid” robotic hand built using real human muscle cells

Biology, Cyborg, robotics, Science / Beth Washington / March 15, 2025

Biohybrid robots work by combining biological components like muscles, plant material, and even fungi with non-biological materials. While we are pretty good at making the non-biological parts work, we’ve always had a problem with keeping the organic components alive and well. This is why machines driven by biological muscles have always been rather small and simple—up to a couple centimeters long and typically with only a single actuating joint.

“Scaling up biohybrid robots has been difficult due to the weak contractile force of lab-grown muscles, the risk of necrosis in thick muscle tissues, and the challenge of integrating biological actuators with artificial structures,” says Shoji Takeuchi, a professor at the Tokyo University, Japan. Takeuchi led a research team that built a full-size, 18 centimeter-long biohybrid human-like hand with all five fingers driven by lab-grown human muscles.

Keeping the muscles alive

Out of all the roadblocks that keep us from building large-scale biohybrid robots, necrosis has probably been the most difficult to overcome. Growing muscles in a lab usually means a liquid medium to supply nutrients and oxygen to muscle cells seeded on petri dishes or applied to gel scaffoldings. Since these cultured muscles are small and ideally flat, nutrients and oxygen from the medium can easily reach every cell in the growing culture.

When we try to make the muscles thicker and therefore more powerful, cells buried deeper in those thicker structures are cut off from nutrients and oxygen, so they die, undergoing necrosis. In living organisms, this problem is solved by the vascular network. But building artificial vascular networks in lab-grown muscles is still something we can’t do very well. So, Takeuchi and his team had to find their way around the necrosis problem. Their solution was sushi rolling.

The team started by growing thin, flat muscle fibers arranged side by side on a petri dish. This gave all the cells access to nutrients and oxygen, so the muscles turned out robust and healthy. Once all the fibers were grown, Takeuchi and his colleagues rolled them into tubes called MuMuTAs (multiple muscle tissue actuators) like they were preparing sushi rolls. “MuMuTAs were created by culturing thin muscle sheets and rolling them into cylindrical bundles to optimize contractility while maintaining oxygen diffusion,” Takeuchi explains.

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