You may have heard that sharks are older than trees. And yes, sharks are truly ancient, with an evolutionary lineage dating back hundreds of millions of years.

But are they really older than trees? Experts told Live Science that the answer depends on what we classify as a shark.

"It's all in the fine print," John Maisey, the curator-in-charge emeritus of fossil fish at the American Museum of Natural History in New York, told Live Science. "The takeaway is that the shark lineage within the fishes generally does go back further than trees. But it really depends on how you define what we mean by shark."

The modern sharks we see today first emerged around 195 million years ago, during the Jurassic period. Fossils of ancient sharks from this time can be traced to living lineages, namely Hexanchiformes, an order of sharks identified by their six or seven gills and single dorsal fin.

This means that modern sharks, at least, are not older than trees. Experts generally agree that trees first evolved in the Middle Devonian epoch, around 380 million to 390 million years ago. "I think it's not very controversial, when we had the first trees," Cindy Looy, a paleobotanist at the University of California, Berkeley, told Live Science.

For instance, the first true tree in the evolutionary record is considered to be Archaeopteris, an extinct genus discovered in a 385 million-year-old fossil forest near Cairo, New York. Looking at these fossils, Archaeopteris has many characteristics of trees we have today, including a tall, woody trunk; leaves; and a deep root system. Other early trees — such as Eospermatopteris found in ancient forests near Gilboa, New York, and Calamophyton in southwest England  — also appeared in the fossil record 390 million and 393 million years ago, respectively.

But when we look at the extinct relatives of modern sharks, "that's where it gets a bit wobbly," Maisey said. There are fossils from the sister groups of modern sharks that can be traced back through the Permian period and into the Devonian period (around 359 million to 420 million years ago). The most abundant group are hybodonts, an extinct group of spiny fish that have a unique calcification pattern in their cartilage that is similar to that of modern sharks.

"It’s called tessellated calcified cartilage, and that's a very important hallmark of most of the shark-like fishes and their ancestors," said Maisey, who has studied a spiny fish fossil called Doliodus problematicus from the early Devonian. If this definition is used, these sharks first appeared around 400 million years ago, before trees emerged.

Sharks' rough skin can be traced even further back, with the dermal denticles — the tooth-like scales that roughen a shark's skin — first appearing in the fossil record around 450 million years ago.

These transition fossils, where fish were evolving into sharks and gaining shark-like traits, introduce a gray area in the definition of sharks. "When you get back into the ancient past, when you're not dealing with things that we have living examples to compare with anymore, then it becomes a bit more tricky [to figure out what they are]," Maisey said...

You finally started an online conversation with a stranger you find attractive, yet you don't really know what to say. They seem happy to talk, but you struggle to find the correct responses. You worry that their patience is growing thin. You pray for some guidance. Luckily, the solution could be just a few clicks away.

After all, you have the power of AI at your fingertips. Why not use it to come up with something fun and interesting to say?

Yet many of us might hesitate in this scenario. Researchers have already warned of "cognitive debt"—students can use AI to write excellent assignments, but then fail miserably in final exams because they remember nothing. No one would want to show up to a date unable to recall anything they had copied and pasted into an online conversation.

Flirting online, like many other emotionally loaded tasks such as writing an apology, a eulogy or a message of congratulations, reflects how you feel about the person. The philosopher Talbot Brewer wrote that a person's efforts to make sense of their emotions through articulating them can reveal what they value.

For example, suppose someone thought she didn't especially care about her work. But then she found herself feeling pride when she was promoted. Her emotion may reveal to her that she does in fact care about workplace success.

How your emotions reveal yourself to you
In our recent research, we contend that using AI to flirt—or for any other task where personal connection is valuable—risks bypassing those moments where emotions can reveal important self-knowledge.

Perhaps in flirting online, a person may not read what their date says carefully. Instead, they might quickly copy the text into ChatGPT and then equally quickly paste the response back into the chat.

Alternatively, perhaps an AI wingman is already integrated into the dating app, allowing people to simply click and send the suggested text. They don't pay attention to what the date says, maybe overlooking potential deal-breakers, things that might be odd or small stylistic details that would otherwise give them some pause.

By outsourcing this emotional task to ChatGPT, it's possible for a person to deprive themselves of the opportunity to really let the moments affect them. They could miss the chance to properly consider whether they would be happy to make compromises for their date. They may not even know whether they are genuinely excited about the date.

Instead of slowly articulating their feelings and, in so doing, working out what they value in a relationship, they are authorizing AI to say whatever might impress their date.

There's also the issue of privacy—the flirty exchanges could find their way into training data. And is the AI wingman even trustworthy? It could misrepresent the person using it—and the other party might feel they'd suffered a deception. Even before AI, researchers have questioned whether lying on dating platforms invalidates consent.

At the end of the day, it just feels a bit disrespectful. The output of AI has little to do with how someone feels about their date, but draws more from the training data. This data has nothing to do with the person or their date.

But maybe some people are less careless. Plenty of daters would make sure to scrutinize the AI output before sending it.

Yet humans have a tendency to overly trust AI. Another study found that when people regularly let AI produce their first draft, they tend to accept the output uncritically. The study also found that people can easily adopt the biases of large language models (LLMs), even if they know those biases exist...

We all know that black holes can collide. It has happened since black holes began to form, early in cosmic time. The result is always a clash that gives off gravitational waves and a giant bang. Since black holes have such strong gravity, it's almost impossible to imagine a way that any force could break one apart. Yet, that's the task that a group of scientists in Europe set for themselves.

In a study of possible mechanisms for black hole fragmentation, Francesco Sannino of the University of Naples Federico II in Italy and the Quantum Field Theory Center at the University of Southern Denmark, along with Giacomo Cacciapaglia (Laboratoire de Physique Théorique et Hautes Énergies) and Manuel Del Piano and Vania Vellucci, both from the Quantum Field Theory Center, conducted a series of calculations showing that under the right conditions, a black hole could split up into two black holes. It's an unusual possibility, to say the least, but the team has calculated what needs to happen if such an event were to occur.

The two pieces would have to stay apart, according to Sannino. "The two resulting black holes must also be able to separate rather than immediately fall back together. When we include this requirement, the window largely closes again, except possibly for black holes rotating close to their maximum possible rate," he said. If such a split-up could happen, the event horizon of the black hole would form a trouser-like shape as the split-up proceeded. Essentially, it would form two legs of a pair of pants, which is why the team called it a "pair-of-pants topology."

Could This Happen?
That's one possibility for what happens if/when a black hole splits into pieces. No one has seen such an event (yet), so it's still largely theoretical. There's one major impediment, however. That's called entropy, the measure of how many different microscopic ways a physical system can be arranged while still appearing the same from the outside. For example, a rock's shape can remain solid and static until some outside force changes it, such as heating. In the case of an ordinary, non-rotating black hole, breaking it into two pieces would reduce its entropy and make the process thermodynamically unlikely.

However, let's say we have a rotating black hole, spinning very rapidly. According to the team, such a system could break up into two pieces. However, they have to separate quickly, or risk falling back together. So, it turns out it could happen if both black holes have to keep rotating as fast as they possibly can (or close to it). But what would cause the split to occur? The answer lies in the rotation. It alters the relationship between black hole mass, its angular momentum as it spins, and entropy. It's possible that change could lead to the black hole fragmenting. If so, then the next steps are for the black hole "twins" to move apart and retain the momentum and speed of the original...

Lucid dreaming — in which the dreamer is aware that they are dreaming and can sometimes influence the dream's trajectory — is a skill that can be honed, a new study finds. And the researchers found that doing this is surprisingly easy, after training participants to do exactly that using virtual reality (VR) twice a week for just one month.

The study's results could have practical benefits, said Daniel Morris, a cognitive neuroscientist at Northwestern University who studies dreams and was not involved with the work. "Lucid dreaming can benefit people with nightmares by allowing them to transform their nightmares into positive dreams and feel greater agency in their dreams," Morris told Live Science in an email.

Before this study, published Sept. 28 in the journal Frontiers in Psychology, neuroscientists tried to induce lucid dreaming with various methods. These included meditation exercises and so-called reality checks, in which participants ask themselves while awake whether unusual phenomena they encounter — such as people wearing odd Halloween costumes — are real or if they're dreaming. The idea is that they will ask themselves the same question in their sleep during bizarre dreams.

However, "for most people, our day-to-day lives may not feel 'dream-like,'" Morris said, explaining why reality checks have had mixed results and don't reliably trigger lucid dreaming.

Since dream-like scenarios are rare in waking life, the neuroscientists behind the new study used VR simulations of bizarre situations to complement reality-check exercises...

The world is a far louder and more distracting place than when humans first evolved. But there's increasing evidence that experiencing nature can help restore attention lost to modern distractions, known as "directed attention fatigue."

In research recently published in Environment International, psychologists at Washington University in St. Louis add to growing evidence behind attention restoration theory (ART), the idea that there's something innately restorative to one's attention in experiencing nature and green spaces. WashU researchers wanted to test this effect on children using data from the long-running ABCD study.

Their question: "If a child lives closer to green space, and has more access to green space, does this help them pay attention on demand when it's required, and do they do better at school on achievement tests?" said Carina Fowler, lead author of the study and a postdoctoral researcher in the lab of Deanna Barch, a professor of psychological and brain sciences in Arts & Sciences and the Gregory B. Couch Professor of Psychiatry at WashU Medicine.

It turns out those neighborhood parks and woods can make a big difference.

"The greater the proximity to green space, the better kids did on objective assessments of their attention performance," Fowler said.

There are many questions about attention restoration theory. This research tackled those questions with a robust data set, using statistical analysis to filter out confounding factors such as income level, ADHD diagnosis and a slew of other measures that could affect attention.

Under the canopy
Studies have long shown that children perform better on sustained attention, inhibitory control and working memory tasks after time in a school garden or a park or on a nature walk. They also score higher on reading and math assessments in greener environments. The question is why, and do all green spaces offer this benefit?

Some studies have found little effect of green space on attention performance, but the proponents of attention restoration theory note that "You have to feel safe in the green space to have an effect," Fowler said, adding that the restoration effect is not as strong if someone is on social media while in that green space. That, and "the kind of green space might matter." ...

The planet Mars shares many landforms and weather patterns with the Earth, including changing seasons, volcanoes, canyons, dust storms and dust devils, and water ice. But one feature that Earth and Mars share among the eight planets in our solar system are polar ice caps. Both are one of each planet’s striking features, but the major difference is while Earth’s polar ice caps are both comprised of water, Mars’ north polar ice cap is only comprised of water while its southern polar ice cap is carbon dioxide. The reasons for this are determined by altitude, but Mars’ northern polar ice cap is one of the most studied regions primarily due to its water ice composition. But how does the north polar ice cap water ice change with the seasons compared to Earth, and what can this teach scientists about Mars’ climate history?

Now, an international team of researchers might have shed new light on this conundrum. As discussed in a recent study published in the Journal of Geophysical Research: Planets, the researchers challenged our understanding of ice deposits in Mars’ northern polar ice cap region. The primary motivation behind this study was to fill a longstanding knowledge gap regarding the seasonal changes in Martian polar ice deposits, specifically focusing on craters. The researchers note that better understanding seasonal changes in polar ice cap deposits could help gain insights into long-term climate changes on the Red Planet...

A U.N. report finds that 252 million hectares (ha) (623 million acres) across 149 countries are being restored, creating more than 1 million green jobs—the largest documented global restoration effort to date.

To reach 2030 commitments, action must rapidly increase, with a particular focus on freshwater, marine and coastal ecosystems, and annual restoration finance must more than quadruple. This investment could generate an estimated 32 million new jobs worldwide by 2030.

The report, "Nature's comeback—scaling ecosystem restoration for people and planet", is published midway through the U.N. Decade on Ecosystem Restoration (2021–2030). It provides the first comprehensive global assessment of progress against commitments to restore around 1 billion hectares (2.47 billion acres) and the Kunming-Montreal Global Biodiversity Framework target to ensure that by 2030, at least 30% of degraded terrestrial, freshwater, marine and coastal ecosystems are under effective restoration.

Co-published by the Food and Agriculture Organization of the United Nations (FAO), the U.N. Environment Programme (UNEP) and the Secretariat of the Convention on Biological Diversity (CBD), the report was launched at a high-level event during the U.N. Biodiversity Conference (COP17). The event recognized five outstanding initiatives in China, Colombia, Ethiopia, Italy and the United States as U.N. World Restoration Flagships—highlighting successful restoration drives around the world.

"Today, we are witnessing the makings of one of the largest movements for nature in recorded history," said Inger Andersen, executive director of UNEP. "Yet, at the halfway point of the U.N. Decade on Ecosystem Restoration, we are still not restoring nature at the scale or speed required. By 2030, we must turn inspiring initiatives into systemwide action—shifting to restoration economies that protect what remains and restore what has been degraded."

The global movement to restore nature extends beyond national programs to cities, schools, businesses and community initiatives. Since the start of the U.N. Decade on Ecosystem Restoration, its partnership network has grown to more than 300 organizations across all regions...

Planetary defense is a growing concern among the scientific community, as efforts have been made to design and implement missions meant to deflect incoming threats to the Earth well in advance. In 2022, NASA intentionally collided the Double Asteroid Redirection test (DART) planetary defense spacecraft into the smaller asteroid of the binary asteroid, Didymos and Dimorphos, with the latter being the smaller one. While the goal was to ascertain if deflecting an asteroid is feasible, how did this influence the geological characteristics of Dimorphos, and what can it teach us about planetary defense missions?

This is the task of a brave robotic explorer known as Hera, which is a spacecraft mission led by the European Space Agency (ESA) in cooperation with NASA and the Japanese Aerospace Exploration Agency (JAXA). Hera recently sent back its first image of Didymos and Dimorphos, which orbit each other as they orbit the Sun, with the image revealing the two asteroids separated, as opposed to seeing a single dot. This comes after Hera was launched in October 2024 and is now about 1,280 kilometers (795 miles) from the well-known binary asteroid, the latter of which is about 197 million kilometers (122 million miles) from Earth. While the larger Didymos is estimated to be 780 meters (2,559 feet) in diameter, the much smaller Dimorphos is estimated to be about 151 meters (495 feet) across.

“For the very first time we are seeing through Hera’s own eyes the very double asteroid system that the mission was designed and built for,” said Ian Carnelli, who is the ESA Head of the Systems Department and the Hera mission manager. “Our views will much grow sharper as Hera comes closer. We will unveil the first detailed images of Dimorphos – the first object in the Solar System to have had its orbit measurably shifted by human action – on 25 November [2026].”

As noted, the goal of the Hera mission will be to conduct follow-up observations and data collection for NASA’s DART planetary defense mission. For this mission, the DART spacecraft intentionally impacted Dimorphos with the goal of ascertaining whether impacting an object could deflect it away from impacting Earth. The intentional impact occurred in September 2022 at 6.1 km/s (3.8 mi/s), resulting in not only slowing Dimorphos’ orbit around Didymos by 32 to 33 minutes, with the initial goal being at least 73 seconds. Thus, the mission was deemed a resounding success, and the researchers even observed an ejecta plume from the surface of Dimorphos as far as 10,000 kilometers (6,214 miles) into space.

Along with conducting observational analyses of the post-collision Dimorphos surface, Hera will also deploy two shoebox-sixed CubeSats named Milani and Juventas since Hera can’t fly that close to the surface. While Milani’s task is to perform a close-up mineralogical analysis of the DART impact site, Juventas will be tasked with using ground-penetrating radar to peer about 100 meters (328 feet) beneath Dimorphos’ surface to ascertain whether its interior is solid rock or a loose rubble pile which has been proposed by researchers...

Zombies have taken many forms in popular culture. In Michael Jackson's "Thriller" music video, corpses climb out of their graves and perform an impressively coordinated dance. In HBO's "The Last of Us," a fungus infects humans, takes over their bodies and turns them into hosts that help spread the infection. Even Plankton has tried his hand at taking control of another organism in "SpongeBob SquarePants."

These examples are fictional, but they all play with the same unsettling idea: Can one organism take control of another, even after death? In nature, the answer is not quite as dramatic, but some parasites and fungi come surprisingly close.

I spend much of my time as a biomedical engineer and synthetic biologist thinking about how biological systems sense signals, process information and change their behavior. That is part of what makes the idea of one organism taking control of another so fascinating to me.

Some parasites and fungi can alter the behavior of a living host in ways that benefit the parasite. They do not bring the dead back to life. Instead, they interfere with biological systems that control movement, motivation and decision-making.

Zombie ants and fungi
The best-known example of a parasite changing its host's behavior is the "zombie ant" fungus, Ophiocordyceps, which helped inspire "The Last of Us."

The life cycle of the zombie ant fungus begins when fungal spores land on an ant. The spores stick to the ant's outer surface and eventually break through it, allowing the fungus to enter the body. Once inside, the fungus grows and spreads while the ant is still alive. The infection can develop over several weeks before the most dramatic changes in the ant's behavior begin.

Eventually, the infected ant leaves the colony and begins wandering and climbing vegetation. This behavior moves the ant away from its normal habitat and into a location that favors fungal reproduction and dispersal. Near the end of the infection, the ant bites tightly onto a leaf, twig or other plant surface and remains attached in what researchers call a death grip.

After the ant dies, the fungus consumes the remaining tissues and produces a stalk from the ant's body. This structure releases spores that can fall on other ants below and begin the cycle again.

How does the fungus make the ant do this? You might imagine fungal cells invading the ant's brain and taking control. Surprisingly, researchers examining infected ants before death found extensive fungal growth throughout the body and around muscle fibers, but not inside the brain. Fungal cells can form networks around the ant's muscles, suggesting that the ability to manipulate behavior may involve communication between the fungus and multiple host tissues rather than direct control of the brain...

Physicists have found evidence of a particle decay so rare that it is expected to occur only around once in every 10 billion "beauty" particles. The result, from the upgraded LHCb experiment at CERN's Large Hadron Collider (LHC), follows a search spanning more than 40 years and brings physicists closer to exploring the "Zeptoverse"—an unexplored world that exists at distances of a billionth of a trillionth of a meter, or a "zeptometer," where new particles and forces of nature may be hiding.

Researchers from The University of Manchester have played key roles in the LHCb experiment and its major upgrade—which can now collect data at up to five times its previous rate—including developing detector technology that has helped make the new measurement possible.

The finding will allow physicists to test the Standard Model, our current best theory of fundamental particles and their interactions, with greater precision and search for signs of particles or forces that may lie beyond it.

Searching for signs of new physics
The LHCb studies particles containing beauty quarks, heavier relatives of the up and down quarks found in the ordinary matter around us.

Beauty quarks are produced in huge numbers in collisions at the LHC but exist for only around one and a half trillionths of a second before decaying.

By making precise measurements of the different ways beauty quarks decay, physicists can detect the influence of new particles that may be far too small to see at the LHC.

The rarer a decay is, the more sensitive it can be to the influence of new particles. These particles could alter how often the decay occurs.

The new result concerns a particularly rare decay known as 'Bd to mu mu,' in which a particle containing a beauty quark decays into two muons, heavier relatives of electrons.

Scientists predict that this happens only around once in every 10 billion beauty particles. Until now, no single experiment had found solid evidence for the process.

The new measurement reached a statistical significance of 3.2 sigma. This is sufficient for physicists to describe the result as the first evidence of the decay, although further data will be needed to reach the five-sigma threshold required to claim a discovery in particle physics...

After 22 years in orbit and a failed rescue mission this summer, it is highly likely that the Neil Gehrels Swift Observatory will crash into Earth sometime next week. It is not known where on the planet the spacecraft—which is roughly as big as a large elevator—will fall. Despite its size, experts say the risk to the public is relatively low.

What is now a useless piece of space junk was for a long time extraordinarily valuable to the scientific community. Launched on November 20, 2004, Swift was a space observatory equipped with three telescopes. It was designed primarily to detect and study gamma-ray bursts, which are among the most energetic explosions in the universe. Swift would locate these events and transmit their positions to observatories around the world for further study.

The observatory was designed to operate for a few years in low Earth orbit, but it far exceeded its expected lifespan, helping to make many important discoveries about the evolution of the cosmos, including the study of supernovas and the destruction of stars by black holes. However, in 2024, increased solar activity heated and expanded the upper layers of Earth’s atmosphere, increasing the drag on the satellite and accelerating its descent. Without a propulsion system capable of correcting its orbit, its days were numbered.

In July 2026, NASA launched a special $30 million mission to rescue Swift. A robotic spacecraft called LINK was supposed to drag Swift away from Earth by 150 miles, giving it a higher orbit and thus extending its operational life. Unfortunately, LINK failed. In August, NASA administrator Jared Isaacman explained that the difficulties that led to the mission’s cancellation were due to problems with the spacecraft’s control system, which made it impossible to keep it properly oriented and stable in space.
...
On October 26, NASA announced that Swift was less than 170 miles from Earth’s surface—a very low orbit for a satellite. According to the agency, the telescopes on board could no longer maintain stable observations of their astronomical targets. Swift conducted its final observation on October 20, then the operations team based at Pennsylvania State University terminated its operational status.
...
The US Space Force estimates Swift is likely to crash on or around Friday, November 6—or at least whatever remains of the satellite will. Most of the space observatory is expected to disintegrate as it reenters the atmosphere...

What’s on your mind right now? You can probably answer this question without thinking too hard about it. Being aware of our own thought processes — a capacity called introspection — seems to come naturally to us.

Yet among philosophers and psychologists, introspection is a subject of active debate. Some think it’s closely related to consciousness. Others argue that it’s an elaborate illusion. It’s tricky to test theories of introspection in the lab — or to pin down a precise definition in the first place.

Now, after over a century of studying introspection in humans and animals, researchers are beginning to explore the phenomenon in unlikely new subjects — large language models. These systems, which are based on mathematical structures called neural networks, excel at cognitive tasks that until recently seemed exclusive to humans. Can they introspect as well?

In 2025, Jack Lindsey, a researcher at Anthropic, devised a way to test introspection in language models by injecting “thoughts” into their neural networks — in a kind of targeted digital neurosurgery. Lindsey’s experiment demonstrated that models could at least sometimes detect and describe these injections. It looked a lot like introspection.

Lindsey’s paper was deliberately limited in scope — it didn’t make broader claims about consciousness. (In particular, it did not imply that language models have subjective first-person experiences.) Even so, it caused a stir online. Researchers rushed to replicate Lindsey’s study with other models.

In the year since, a clearer picture has emerged. Some aspects of the phenomenon Lindsey observed have simpler explanations unrelated to introspection. Others have proved harder to explain away, but whether they should count as introspection remains hotly contested...

It's the end of an era: NASA's Swift telescope has reached the conclusion of its nearly 22-year mission, burning up in Earth's atmosphere after studying some of the universe's most powerful and mysterious events.

According to NASA, the spacecraft reentered the atmosphere at "7:39 a.m. EST Wednesday over the North Sumatra region of Indonesia, at approximately 3.4 degrees north latitude and 98.6 degrees east longitude." NASA expected most of the telescope's structure to burn up during its passage through Earth's atmosphere, estimating a 1-in-2,100 chance of any surviving debris falling over a populated area. No damage or injuries have been reported.

Weighing approximately 3,200 pounds (1,450 kilograms), the Neil Gehrels Swift Observatory was initially designed for a two-year mission, but it far exceeded expectations. Over two decades, Swift became an important tool in the study of gamma-ray bursts, supernovas, black holes and other cosmic phenomena.

Exceeding expectations
Launched in November 2004, Swift was designed to detect gamma-ray bursts, powerful explosions that occur throughout the universe. Its three onboard telescopes let scientists observe cosmic events across different wavelengths, including ultraviolet, optical and X-ray light. The telescope could swivel to focus on different sky targets in a matter of minutes, allowing it to rapidly follow up on sudden events like supernova explosions.

NASA estimates that Swift's scientific observations have contributed to approximately 7,000 research papers, leaving behind an extensive collection that scientists can continue studying for years...

Martian dust is a major hurdle for human missions to Mars. Like Moon dust, its fine size and electrostatically charged nature allow it to stick to spacesuits, metal, and just about any other surface they come into contact with. Dust storms are also common on Mars, ranging from small whirlwinds that happen daily to global dust storms that occur once every 3 Martian years (~5.5 Earth years) and envelop the entire planet. Due to the low density of Mars' atmosphere, these storms don't generate much physical force.

The danger lies in how the dust plays havoc with instruments, machine parts, and astronaut health and safety. Given how well it adheres to surfaces, Apollo astronauts found that lunar dust accompanied them back into their landing modules, degrading mechanical joints and seals and causing respiratory problems. A recent study led by Washington University in St. Louis (WashU) highlights the need, using data from NASA's Perseverance rover, for sufficient astronaut training to prepare for the Martian environment.

In addition to its array of sensors, cameras, drilling equipment, and sample cache, Perseverance also carries small swatches of spacesuit material that are constantly exposed to Mars' atmosphere. Using data acquired by the rover's Planetary Instrument for X-ray Lithochemistry (PIXL), the team examined the swatches for signs of wear and tear. They also applied a method developed by VanBommel to estimate the size of each particle in the PIXL data, providing the first direct characterization of fine (≲2.5 µm) and ultrafine particles (≲0.1 µm).

Their analysis found that the swatches showed little visible wear after 1,645 Martian days (sols) of exposure, largely because the particles observed were much smoother than the jagged grains found on the Moon. In summary, the results showed that Martian dust may be less likely to be abrasive to equipment or harmful to astronaut health than lunar regolith. The PIXL data also allowed the team to analyze the chemical composition of the particles that had caked the swatches.

From this, the team confirmed the presence of perchlorates and other toxins, as well as high levels of sulfur, iron, and silica in the dust grains. In addition, Martian dust can be exceptionally fine, with some ultrafine particles measuring as little as 100 nanometers (nm) in diameter. On Earth, ultrafine particles typically come in the form of smoke and air pollution, which can cause significant health problems because they can sink deep into the lungs and enter the bloodstream. With Martian dust carrying perchlorates and other toxins, the health risk is magnified...

What if a robot could be squishy? Soft, flexible robots could be useful for a wide variety of applications, including artificial muscles and wearable devices—or really any application where a robot must be especially delicate.

This is what has fueled development of “soft actuators” that can flex like a bicep and have a fine-tuned sense of touch as in the human hand. Like your stereotypical robot, soft actuators convert energy—such as electricity, heat, or light—into mechanical motion, but they look nothing like the metal and wire constructs that the word “robot” most often evokes.

One variety of these soft robots, known as bioactuators, utilizes the functions of living cells to generate motion. These biological machines have attracted particular attention in recent years, and now a research team at Delft University of Technology in the Netherlands has developed a soft robotic arm colonized by algae on its surface, and when the microbes photosynthesize, the arm moves.

“We didn’t start with a specific application. Our goal has always been to bring the research of living materials to new levels,” Marie-Eve Aubin-Tam, who led the research, explained in a press release. “We wanted to explore what becomes possible when living cells are integrated into functional materials.” ...