Science – Page 13

Cheerios effect inspires novel robot design

3D printing, active matter, Cheerios effect, fluid dynamics, Marangoni effect, Physics, robotics, Science / Kris Guyer / December 3, 2024

There’s a common popular science demonstration involving “soap boats,” in which liquid soap poured onto the surface of water creates a propulsive flow driven by gradients in surface tension. But it doesn’t last very long since the soapy surfactants rapidly saturate the water surface, eliminating that surface tension. Using ethanol to create similar “cocktail boats” can significantly extend the effect because the alcohol evaporates rather than saturating the water.

That simple classroom demonstration could also be used to propel tiny robotic devices across liquid surfaces to carry out various environmental or industrial tasks, according to a preprint posted to the physics arXiv. The authors also exploited the so-called “Cheerios effect” as a means of self-assembly to create clusters of tiny ethanol-powered robots.

As previously reported, those who love their Cheerios for breakfast are well acquainted with how those last few tasty little “O”s tend to clump together in the bowl: either drifting to the center or to the outer edges. The “Cheerios effect is found throughout nature, such as in grains of pollen (or, alternatively, mosquito eggs or beetles) floating on top of a pond; small coins floating in a bowl of water; or fire ants clumping together to form life-saving rafts during floods. A 2005 paper in the American Journal of Physics outlined the underlying physics, identifying the culprit as a combination of buoyancy, surface tension, and the so-called “meniscus effect.”

It all adds up to a type of capillary action. Basically, the mass of the Cheerios is insufficient to break the milk’s surface tension. But it’s enough to put a tiny dent in the surface of the milk in the bowl, such that if two Cheerios are sufficiently close, the curved surface in the liquid (meniscus) will cause them to naturally drift toward each other. The “dents” merge and the “O”s clump together. Add another Cheerio into the mix, and it, too, will follow the curvature in the milk to drift toward its fellow “O”s.

Physicists made the first direct measurements of the various forces at work in the phenomenon in 2019. And they found one extra factor underlying the Cheerios effect: The disks tilted toward each other as they drifted closer in the water. So the disks pushed harder against the water’s surface, resulting in a pushback from the liquid. That’s what leads to an increase in the attraction between the two disks.

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Researchers finally identify the ocean’s “mystery mollusk”

Biology, marine biology, phylogenetic, Science, Weird / Mike M. / December 2, 2024

Some of the most bizarre lifeforms on Earth lurk in the deeper realms of the ocean. There was so little known about one of these creatures that it took 20 years just to figure out what exactly it was. Things only got weirder from there.

The organism’s distinctive, glowing presence was observed by multiple deep-sea missions between 2000 to 2021 but was simply referred to as “mystery mollusk.” A team of Monterey Bay Aquarium Research Institute (MBARI) researchers has now reviewed extensive footage of past mystery mollusk sightings and used MBARI’s remotely operated vehicles (ROVs) to observe it and collect samples. They’ve given it a name and have finally confirmed that it is a nudibranch—the first and only nudibranch known to live at such depths.

Bathydevius caudactylus, as this nudibranch is now called, lives 1,000–4,000 meters (3,300–13,100 feet) deep in the ocean’s bathypelagic or midnight zone. It moves like a jellyfish, eats like a Venus flytrap, and is bioluminescent, and its genes are distinct enough for it to be classified as the first member of a new phylogenetic family.

“Anatomy, diet, behavior, bioluminescence, and habitat distinguish this surprising nudibranch from all previously described species, and genetic evidence supports its placement in a new family,” the MBARI research team said in a study recently published in Deep Sea Research.

Is that a…?

Nudibranchs are gastropods, which literally translates to “stomach foot” since the “foot” they crawl around on when not swimming is right below their guts. They are part of a larger group that includes terrestrial and aquatic snails and slugs. B. caudactylus, however, seems to get around more like a jellyfish than a sea slug. It mostly swims using an oral hood that opens and closes to propel itself backward through the water in a manner similar to many jellyfish.

The hood of B. caudactylus can also act something like a Venus flytrap. While it is not a hinged structure like the leaves of the plant, it is used to trap prey. Typically small crustaceans, the prey are then pushed to the mouth at the back of the hood.

The mystery mollusk.

The nudibranch also seems to have a unique way of avoiding becoming food itself. Projections at the end of its tail, known as dactyls, can detach if needed, much like the tails of some lizard species. The MBARI team thinks that these dactyls are possibly a lure meant to trick predators while the nudibranch swims away. They later regenerate.

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People will share misinformation that sparks “moral outrage”

Behavioral science, Human behavior, misinformation, rage clicks, Science, Social Media / Kris Guyer / December 2, 2024

People can tell it’s not true, but if they’re outraged by it, they’ll share anyway.

Rob Bauer, the chair of a NATO military committee, reportedly said, “It is more competent not to wait, but to hit launchers in Russia in case Russia attacks us. We must strike first.” These comments, supposedly made in 2024, were later interpreted as suggesting NATO should attempt a preemptive strike against Russia, an idea that lots of people found outrageously dangerous.

But lots of people also missed a thing about the quote: Bauer has never said it. It was made up. Despite that, the purported statement got nearly 250,000 views on X and was mindlessly spread further by the likes of Alex Jones.

Why do stories like this get so many views and shares? “The vast majority of misinformation studies assume people want to be accurate, but certain things distract them,” says William J. Brady, a researcher at Northwestern University. “Maybe it’s the social media environment. Maybe they’re not understanding the news, or the sources are confusing them. But what we found is that when content evokes outrage, people are consistently sharing it without even clicking into the article.” Brady co-authored a study on how misinformation exploits outrage to spread online. When we get outraged, the study suggests, we simply care way less if what’s got us outraged is even real.

Tracking the outrage

The rapid spread of misinformation on social media has generally been explained by something you might call an error theory—the idea that people share misinformation by mistake. Based on that, most solutions to the misinformation issue relied on prompting users to focus on accuracy and think carefully about whether they really wanted to share stories from dubious sources. Those prompts, however, haven’t worked very well. To get to the root of the problem, Brady’s team analyzed data that tracked over 1 million links on Facebook and nearly 45,000 posts on Twitter from different periods ranging from 2017 to 2021.

Parsing through the Twitter data, the team used a machine-learning model to predict which posts would cause outrage. “It was trained on 26,000 tweets posted around 2018 and 2019. We got raters from across the political spectrum, we taught them what we meant by outrage, and got them to label the data we later used to train our model,” Brady says.

The purpose of the model was to predict whether a message was an expression of moral outrage, an emotional state defined in the study as “a mixture of anger and disgust triggered by perceived moral transgressions.” After training, the AI was effective. “It performed as good as humans,” Brady claims. Facebook data was a bit more tricky because the team did not have access to comments; all they had to work with were reactions. The reaction the team chose as a proxy for outrage was anger. Once the data was sorted into outrageous and not outrageous categories, Brady and his colleagues went on to determine whether the content was trustworthy news or misinformation.

“We took what is now the most widely used approach in the science of misinformation, which is a domain classification approach,” Brady says. The process boiled down to compiling a list of domains with very high and very low trustworthiness based on work done by fact-checking organizations. This way, for example, The Chicago Sun-Times was classified as trustworthy; Breitbart, not so much. “One of the issues there is that you could have a source that produces misinformation which one time produced a true story. We accepted that. We went with statistics and general rules,” Brady acknowledged. His team confirmed that sources classified in the study as misinformation produced news that was fact-checked as false six to eight times more often than reliable domains, which Brady’s team thought was good enough to work with.

Finally, the researchers started analyzing the data to answer questions like whether misinformation sources evoke more outrage, whether outrageous news was shared more often than non-outrageous news, and finally, what reasons people had for sharing outrageous content. And that’s when the idealized picture of honest, truthful citizens who shared misinformation just because they were too distracted to recognize it started to crack.

Going with the flow

The Facebook and Twitter data analyzed by Brady’s team revealed that misinformation evoked more outrage than trustworthy news. At the same time, people were way more likely to share outrageous content, regardless of whether it was misinformation or not. Putting those two trends together led the team to conclude outrage primarily boosted the spread of fake news since reliable sources usually produced less outrageous content.

“What we know about human psychology is that our attention is drawn to things rooted in deep biases shaped by evolutionary history,” Brady says. Those things are emotional content, surprising content, and especially, content that is related to the domain of morality. “Moral outrage is expressed in response to perceived violations of moral norms. This is our way of signaling to others that the violation has occurred and that we should punish the violators. This is done to establish cooperation in the group,” Brady explains.

This is why outrageous content has an advantage in the social media attention economy. It stands out, and standing out is a precursor to sharing. But there are other reasons we share outrageous content. “It serves very particular social functions,” Brady says. “It’s a cheap way to signal group affiliation or commitment.”

Cheap, however, didn’t mean completely free. The team found that the penalty for sharing misinformation, outrageous or not, was loss of reputation—spewing nonsense doesn’t make you look good, after all. The question was whether people really shared fake news because they failed to identify it as such or if they just considered signaling their affiliation was more important.

Flawed human nature

Brady’s team designed two behavioral experiments where 1,475 people were presented with a selection of fact-checked news stories curated to contain outrageous and not outrageous content; they were also given reliable news and misinformation. In both experiments, the participants were asked to rate how outrageous the headlines were.

The second task was different, though. In the first experiment, people were simply asked to rate how likely they were to share a headline, while in the second they were asked to determine if the headline was true or not.

It turned out that most people could discern between true and fake news. Yet they were willing to share outrageous news regardless of whether it was true or not—a result that was in line with previous findings from Facebook and Twitter data. Many participants were perfectly OK with sharing outrageous headlines, even though they were fully aware those headlines were misinformation.

Brady pointed to an example from the recent campaign, when a reporter pushed J.D. Vance about false claims regarding immigrants eating pets. “When the reporter pushed him, he implied that yes, it was fabrication, but it was outrageous and spoke to the issues his constituents were mad about,” Brady says. These experiments show that this kind of dishonesty is not exclusive to politicians running for office—people do this on social media all the time.

The urge to signal a moral stance quite often takes precedence over truth, but misinformation is not exclusively due to flaws in human nature. “One thing this study was not focused on was the impact of social media algorithms,” Brady notes. Those algorithms usually boost content that generates engagement, and we tend to engage more with outrageous content. This, in turn, incentivizes people to make their content more outrageous to get this algorithmic boost.

Science, 2024. DOI: 10.1126/science.adl2829

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

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Over the weekend, China debuted a new rocket on the nation’s path to the Moon

china, launch, long march, long march 12, moon, Science, Space / Tim Belzer / December 2, 2024

Depending on how you count them, China now has roughly 18 types of active space launchers.

China’s new Long March 12 rocket made a successful inaugural flight Saturday, placing two experimental satellites into orbit and testing uprated, higher-thrust engines that will allow a larger Chinese launcher in development to send astronauts to the Moon.

The 203-foot-tall (62-meter) Long March 12 rocket lifted off at 9: 25 am EST (14: 25 UTC) Saturday from the Wenchang commercial launch site on Hainan Island, China’s southernmost province. This was also the first rocket launch from a new commercial spaceport at Wenchang, consisting of two launch sites a short distance from a pair of existing launch pads used by heavier rockets primarily geared for government missions.

The two-stage rocket delivered two technology demonstration satellites into a near-circular 50-degree-inclination orbit with an average altitude of nearly 650 miles (about 1,040 kilometers), according to US military tracking data.

The Long March 12 is the newest member of China’s Long March rocket family, which has been flying since China launched its first satellite into orbit in 1970. The Long March rockets have significantly evolved since then and now include a range of launch vehicles of different sizes and designs.

Versions of the Long March 2, 3, and 4 rockets have been flying since the 1970s and 1980s, burning the same toxic mix of hypergolic propellants as China’s early ICBMs. More recently, China debuted the Long March 5, 6, 7, and 8 rockets consuming the cleaner combination of kerosene and liquid oxygen propellants. These new rockets provide China with a spectrum of small, medium, and heavy-lift launch capabilities.

So many rockets

So, why bother with yet another Long March rocket? One reason is that Chinese officials seek a less expensive rocket to deploy thousands of small satellites for the country’s Internet mega-constellations to rival SpaceX’s Starlink network. Another motivation is to demonstrate the performance of upgraded rocket engines, new technologies, and fresh designs, some of which appear to copy SpaceX’s workhorse Falcon 9 rocket.

Like all of China’s other existing rockets, the Long March 12 configuration that flew Saturday is fully disposable. At the Zhuhai Airshow earlier this month, China’s largest rocket company displayed another version of the Long March 12 with a reusable first stage but with scant design details.

The Long March 12 is powered by four kerosene-fueled YF-100K engines on its first stage, generating more than 1.1 million pounds, or 5,000 kilonewtons of thrust at full throttle. These engines are upgraded, higher-thrust versions of the YF-100 engines used on several other types of Long March rockets.

Models of the Long March rockets on display at the China National Space Administration (CNSA) booth during the China International Aviation & Aerospace Exhibition in Zhuhai, China, on November 12, 2024. In this image, models of a future reusable version of the Long March 12 (left) and the super-heavy Long March 9 (right) are visible. Credit: Qilai Shen/Bloomberg via Getty Images

Notably, China will use the YF-100K variant on the heavy-lift Long March 10 rocket in development to launch Chinese astronauts to the Moon. The heaviest version of the Long March 10 will use 21 of these YF-100K engines on its core stage and strap-on boosters. Now, Chinese engineers have tested the upgraded YF-100K in flight, with favorable results from Saturday’s launch.

China is also developing a new crew-rated spacecraft and lunar lander that will launch on Long March 10 rockets, eyeing a human landing on the lunar surface by 2030. The Long March 10 will have a reusable first stage like the Falcon 9, and China is now working on a super-heavy fully reusable rocket that appears to be a clone of SpaceX’s Starship. This Long March 9 rocket, which probably won’t fly until the 2030s, will enable larger-scale sustained lunar exploration by China.

And now, the details

The Long March 12 was developed by the Shanghai Academy of Spaceflight Technology, also known as SAST, one of the two main state-owned organizations in charge of designing and manufacturing Long March rockets. Together with the Beijing-based China Academy of Launch Vehicle Technology, SAST is part of the China Aerospace Science and Technology Corporation, the largest government-run enterprise overseeing the Chinese space program.

According to SAST, the Long March 12 is capable of delivering a payload of at least 12 metric tons (26,455 pounds) into low-Earth orbit and about half that to a somewhat higher Sun-synchronous orbit. Two kerosene-fueled YF-115 engines power the Long March 12’s upper stage.

The Long March 12 is also China’s first 3.8-meter (12.5-foot) diameter rocket, which is an optimal match between the width of the booster and lift capability, allowing it to be transported by railway to launch sites across China, according to the state-run Xinhua news agency.

China’s older Long March rocket variants are slimmer and generally require engineers to strap together multiple first-stage boosters in a cluster arrangement to achieve performance similar to the Long March 12. The core of the heavy-lift Long March 5 is around 5 meters in diameter and must be transported by sea.

China’s first Long March 12 rocket on its launch pad before liftoff. Credit: Photo by VCG/VCG via Getty Images

In a post-launch press release, SAST identified several other “technology breakthroughs” flying on the Long March 12 rocket. These include a health management system that can diagnose anomalies in flight and adjust the rocket’s trajectory in real time to compensate for any minor problems. The Long March 12 is also China’s first rocket to use cryogenic helium to pressurize its liquid oxygen tanks, and its tanks are made of an aluminum-lithium alloy to save weight.

The Long March 12 is also the first rocket of its size in the Long March family to be assembled on its side instead of stacked vertically on its launch mount. After integrating the rocket in a nearby hangar, technicians transferred the first Long March 12 to its launch pad horizontally, then raised it vertical with an erector system. This is the same way SpaceX integrates and transports Falcon 9 rockets to the launch pad. SpaceX copied this horizontal integration approach from older Soviet-era rockets, and it offers several advantages, allowing teams to assemble rockets faster without the need for large overhead cranes in tall, cavernous vertical assembly buildings.

A bug or a feature?

We’ve already mentioned the proliferation of different types of Long March rockets, with nine classes of Long March launchers currently in operation. And each of these comes in multiple sub-variants.

This is a starkly different approach from SpaceX, which flies standardized rockets like the Falcon 9 and Falcon Heavy, which almost always fly in the same configuration, regardless of the payload or destination for each mission. The only exception is when SpaceX launches Dragon crew or cargo capsules on the Falcon 9.

Depending on how you count them, China now has roughly 18 different types of active space launchers. This number doesn’t include the Long March 9 or Long March 10, but it counts all the other Long March configurations, plus numerous small- and medium-class rockets fielded by China’s quasi-commercial space industry.

These startups operate with the blessing of China’s government and, in many cases, got their start by utilizing surplus military equipment and investment from Chinese local or provincial governments. However, the Chinese Communist Party has allowed them to raise capital from private sources, and they operate on a commercial basis, almost exclusively to serve domestic Chinese markets.

In some cases, these launch startups compete for commercial contracts directly with the government-backed Long March rocket family. The Long March 12 could be in the mix for launching large batches of spacecraft for China’s planned satellite Internet networks.

Some of these launch companies are working on reusable rockets similar in appearance to SpaceX’s Falcon 9. All of these rockets, government and commercial, are part of an ecosystem of Chinese launchers tasked with hauling military and commercial satellites into orbit.

The Long March 12 launch Saturday was China’s 58th orbital launch attempt of 2024, and no single subvariant of a Chinese rocket has flown more than seven times this year. This is in sharp contrast to the United States, which has logged 142 orbital launch attempts so far this year, 119 of them by SpaceX’s Falcon 9 or Falcon Heavy rockets.

There are around a dozen US orbital-class launch vehicle types you might call operational. But a few of these, such as Northrop Grumman’s Pegasus XL and Minotaur, and NASA’s Space Launch System, haven’t flown for several years.

SpaceX’s Falcon 9 is now the dominant leader in the US launch industry. Most of the Falcon 9 launches are filled to capacity with SpaceX’s own Starlink Internet satellites, but many missions fly with their payload fairings only partially full. Still, the Falcon 9 is more affordable on a per-kilogram basis than any other US rocket.

In China, on the other hand, none of the commercial launch startups have emerged as a clear leader. When that happens, if China allows the market to function in a truly commercial manner, some of these Chinese rocket companies will likely fold.

However, China’s government has a strategic interest in maintaining a portfolio of rockets and launch sites, same as the US government. For example, Chinese officials said the new launch site at Wenchang, where the Long March 12 took off from over the weekend, can accommodate 10 or more different types of rockets.

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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Supermassive black hole binary emits unexpected flares

astronomy, astrophysics, black hole binary, black holes, Science, supermassive black hole / Tim Belzer / December 1, 2024

“In addition to stars, gas clouds can also be disrupted by SMBHs and their binaries,” they said in the same study. “The key difference is that the clouds can be comparable to or even larger than the binary separation, unlike stars, which are always much smaller. “

Looking at the results of a previous study that numerically modeled this type of situation also suggested a gas cloud. Just like the hypothetical supermassive black hole binary in the model, AT 2021hdr would accrete large amounts of material every time the black holes were halfway through orbiting each other and had to cross the cloud to complete the orbit—their gravity tears away some of the cloud, which ends up in their accretion disks, every time they cross it. They are now thought to take in anywhere between three and 30 percent of the cloud every few cycles. From a cloud so huge, that’s a lot of gas.

The supermassive black holes in AT 2021hdr are predicted to crash into each other and merge in another 70,000 years. They are also part of another merger, in which their host galaxy is gradually merging with a nearby galaxy, which was first discovered by the same team (this has no effect on the BSMBH tidal disruption of the gas cloud).

How the behavior of AT 2021hdr develops could tell us more about its nature and uphold or disprove the idea that it is eating away at a gaseous cloud instead of a star or something else. For now, it seems these black holes don’t just get gas from what they eat—they eat the gas itself.

Astronomy & Astrophysics, 2024. DOI: 10.1051/0004-6361/202451305

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How should we treat beings that might be sentient?

Biology, consciousness, ethics, neurobiology, Science, sentience / Tim Belzer / November 30, 2024

Being aware of the maybe self-aware

A book argues that we’ve not thought enough about things that might think.

What rights should a creature with ambiguous self-awareness, like an octopus, be granted. Credit: A. Martin UW Photography

If you aren’t yet worried about the multitude of ways you inadvertently inflict suffering onto other living creatures, you will be after reading The Edge of Sentience by Jonathan Birch. And for good reason. Birch, a Professor of Philosophy at the London College of Economics and Political Science, was one of a team of experts chosen by the UK government to establish the Animal Welfare Act (or Sentience Act) in 2022—a law that protects animals whose sentience status is unclear.

According to Birch, even insects may possess sentience, which he defines as the capacity to have valenced experiences, or experiences that feel good or bad. At the very least, Birch explains, insects (as well as all vertebrates and a selection of invertebrates) are sentience candidates: animals that may be conscious and, until proven otherwise, should be regarded as such.

Although it might be a stretch to wrap our mammalian minds around insect sentience, it is not difficult to imagine that fellow vertebrates have the capacity to experience life, nor does it come as a surprise that even some invertebrates, such as octopuses and other cephalopod mollusks (squid, cuttlefish, and nautilus) qualify for sentience candidature. In fact, one species of octopus, Octopus vulgaris, has been protected by the UK’s Animal Scientific Procedures Act (ASPA) since 1986, which illustrates how long we have been aware of the possibility that invertebrates might be capable of experiencing valenced states of awareness, such as contentment, fear, pleasure, and pain.

A framework for fence-sitters

Non-human animals, of course, are not the only beings with an ambiguous sentience stature that poses complicated questions. Birch discusses people with disorders of consciousness, embryos and fetuses, neural organoids (brain tissue grown in a dish), and even “AI technologies that reproduce brain functions and/or mimic human behavior,” all of which share the unenviable position of being perched on the edge of sentience—a place where it is excruciatingly unclear whether or not these individuals are capable of conscious experience.

What’s needed, Birch argues, when faced with such staggering uncertainty about the sentience stature of other beings, is a precautionary framework that outlines best practices for decision-making regarding their care. And in The Edge of Sentience, he provides exactly that, in meticulous, orderly detail.

Over more than 300 pages, he outlines three fundamental framework principles and 26 specific case proposals about how to handle complex situations related to the care and treatment of sentience-edgers. For example, Proposal 2 cautions that “a patient with a prolonged disorder of consciousness should not be assumed incapable of experience” and suggests that medical decisions made on their behalf cautiously presume they are capable of feeling pain. Proposal 16 warns about conflating brain size, intelligence, and sentience, and recommends decoupling the three so that we do not incorrectly assume that small-brained animals are incapable of conscious experience.

Surgeries and stem cells

Be forewarned, some topics in The Edge of Sentience are difficult. For example, Chapter 10 covers embryos and fetuses. In the 1980s, Birch shares, it was common practice to not use anesthesia on newborn babies or fetuses when performing surgery. Why? Because whether or not newborns and fetuses experience pain was up for debate. Rather than put newborns and fetuses through the risks associated with anesthesia, it was accepted practice to give them a paralytic (which prevents all movement) and carry on with invasive procedures, up to and including heart surgery.

After parents raised alarms over the devastating outcomes of this practice, such as infant mortality, it was eventually changed. Birch’s takeaway message is clear: When in doubt about the sentience stature of a living being, we should probably assume it is capable of experiencing pain and take all necessary precautions to prevent it from suffering. To presume the opposite can be unethical.

This guidance is repeated throughout the book. Neural organoids, discussed in Chapter 11, are mini-models of brains developed from stem cells. The potential for scientists to use neural organoids to unravel the mechanisms of debilitating neurological conditions—and to avoid invasive animal research while doing so—is immense. It is also ethical, Birch posits, since studying organoids lessens the suffering of research animals. However, we don’t yet know whether or not neural tissue grown in a dish has the potential to develop sentience, so he argues that we need to develop a precautionary approach that balances the benefits of reduced animal research against the risk that neural organoids are capable of being sentient.

A four-pronged test

Along this same line, Birch says, all welfare decisions regarding sentience-edgers require an assessment of proportionality. We must balance the nature of a given proposed risk to a sentience candidate with potential harms that could result if nothing is done to minimize the risk. To do this, he suggests testing four criteria: permissibility-in-principle, adequacy, reasonable necessity, and consistency. Birch refers to this assessment process as PARC, and deep dives into its implementation in chapter eight.

When applying the PARC criteria, one begins by testing permissibility-in-principle: whether or not the proposed response to a risk is ethically permissible. To illustrate this, Birch poses a hypothetical question: would it be ethically permissible to mandate vaccination in response to a pandemic? If a panel of citizens were in charge of answering this question, they might say “no,” because forcing people to be vaccinated feels unethical. Yet, when faced with the same question, a panel of experts might say “yes,” because allowing people to die who could be saved by vaccination also feels unethical. Gauging permissibility-in-principle, therefore, entails careful consideration of the likely possible outcomes of a proposed response. If an outcome is deemed ethical, it is permissible.

Next, the adequacy of a proposed response must be tested. A proportionate response to a risk must do enough to lessen the risk. This means the risk must be reduced to “an acceptable level” or, if that’s not possible, a response should “deliver the best level of risk reduction that can be achieved” via an ethically permissible option.

The third test is reasonable necessity. A proposed response to a risk must not overshoot—it should not go beyond what is reasonably necessary to reduce risk, in terms of either cost or imposed harm. And last, consistency should be considered. The example Birch presents is animal welfare policy. He suggests we should always “aim for taxonomic consistency: our treatment of one group of animals (e.g., vertebrates) should be consistent with our treatment of another (e.g., invertebrates).”

The Edge of Sentience, as a whole, is a dense text overflowing with philosophical rhetoric. Yet this rhetoric plays a crucial role in the storytelling: it is the backbone for Birch’s clear and organized conclusions, and it serves as a jumping-off point for the logical progression of his arguments. Much like “I think, therefore I am” gave René Descartes a foundation upon which to build his idea of substance dualism, Birch uses the fundamental position that humans should not inflict gratuitous suffering onto fellow creatures as a base upon which to build his precautionary framework.

For curious readers who would prefer not to wade too deeply into meaty philosophical concepts, Birch generously provides a shortcut to his conclusions: a cheat sheet of his framework principles and special case proposals is presented at the front of the book.

Birch’s ultimate message in The Edge of Sentience is that a massive shift in how we view beings with a questionable sentience status should be made. And we should ideally make this change now, rather than waiting for scientific research to infallibly determine who and what is sentient. Birch argues that one way that citizens and policy-makers can begin this process is by adopting the following decision-making framework: always avoid inflicting gratuitous suffering on sentience candidates; take precautions when making decisions regarding a sentience candidate; and make proportional decisions about the care of sentience candidates that are “informed, democratic and inclusive.”

You might be tempted to shake your head at Birch’s confidence in humanity. No matter how deeply you agree with his stance of doing no harm, it’s hard to have confidence in humanity given our track record of not making big changes for the benefit of living creatures, even when said creatures includes our own species (cue in global warming here). It seems excruciatingly unlikely that the entire world will adopt Birch’s rational, thoughtful, comprehensive plan for reducing the suffering of all potentially sentient creatures. Yet Birch, a philosopher at heart, ignores human history and maintains a tone of articulate, patient optimism. He clearly believes in us—he knows we can do better—and he offers to hold our hands and walk us through the steps to do so.

Lindsey Laughlin is a science writer and freelance journalist who lives in Portland, Oregon, with her husband and four children. She earned her BS from UC Davis with majors in physics, neuroscience, and philosophy.

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Rocket Report: A good week for Blue Origin; Italy wants its own launch capability

blue origin, china, human spaceflight, italy, launch, rocket lab, rocket report, Science, Space, spacex / Mike M. / November 28, 2024

Blue Origin is getting ready to test-fire its first fully integrated New Glenn rocket in Florida.

Blue Origin’s first fully integrated New Glenn rocket rolls out to its launch pad at Cape Canaveral Space Force Station, Florida. Credit: Blue Origin

Welcome to Edition 7.21 of the Rocket Report! We’re publishing the Rocket Report a little early this week due to the Thanksgiving holiday in the United States. We don’t expect any Thanksgiving rocket launches this year, but still, there’s a lot to cover from the last six days. It seems like we’ve seen the last flight of the year by SpaceX’s Starship rocket. A NASA filing with the Federal Aviation Administration requests approval to fly an aircraft near the reentry corridor over the Indian Ocean for the next Starship test flight. The application suggests the target launch date is January 11, 2025.

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

Another grim first in Ukraine. For the first time in warfare, Russia launched an Intermediate Range Ballistic Missile against a target in Ukraine, Ars reports. This attack on November 21 followed an announcement from Russian President Vladimir Putin earlier the same week that the country would change its policy for employing nuclear weapons in conflict. The IRBM, named Oreshnik, is the longest-range weapon ever used in combat in Europe, and could be refitted to carry nuclear warheads on future strikes.

Putin’s rationale … Putin says his ballistic missile attack on Ukraine is a warning to the West after the US and UK governments approved Ukraine’s use of Western-supplied ATACMS and Storm Shadow tactical ballistic missiles against targets on Russian territory. The Russian leader said his forces could attack facilities in Western countries that supply weapons for Ukraine to use on Russian territory, continuing a troubling escalatory ladder in the bloody war in Eastern Europe. Interestingly, this attack has another rocket connection. The target was apparently a factory in Dnipro that, not long ago, produced booster stages for Northrop Grumman’s Antares rocket.

Blue Origin hops again. Blue Origin launched its ninth suborbital human spaceflight over West Texas on November 22, CollectSpace reports. Six passengers rode the company’s suborbital New Shepard booster to the edge of space, reaching an altitude of 347,661 feet (65.8 miles or 106 kilometers), flying 3 miles (4.8 km) above the Kármán line that serves as the internationally-accepted border between Earth’s atmosphere and outer space. The pressurized capsule carrying the six passengers separated from the booster, giving them a taste of microgravity before parachuting back to Earth.

Dreams fulfilled … These suborbital flights are getting to be more routine, and may seem insignificant compared to Blue Origin’s grander ambitions of flying a heavy-lift rocket and building a human-rated Moon lander. However, we’ll likely have to wait many years before truly routine access to orbital flights becomes available for anyone other than professional astronauts or multimillionaires. This means tickets to ride on suborbital spaceships from Blue Origin or Virgin Galactic are currently the only ways to get to space, however briefly, for something on the order of $1 million or less. That puts the cost of one of these seats within reach for hundreds of thousands of people, and within the budgets of research institutions and non-profits to fund a flight for a scientist, student, or a member of the general public. The passengers on the November 22 flight included Emily Calandrelli, known online as “The Space Gal,” an engineer, Netflix host, and STEM education advocate who became the 100th woman to fly to space. (submitted by Ken the Bin)

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Rocket Lab flies twice in one day. Two Electron rockets took flight Sunday, one from New Zealand’s Mahia Peninsula and the other from Wallops Island, Virginia, making Rocket Lab the first commercial space company to launch from two different hemispheres in a 24-hour period, Payload reports. One of the missions was the third of five launches for the French Internet of Things company Kinéis, which is building a satellite constellation. The other launch was an Electron modified to act as a suborbital technology demonstrator for hypersonic research. Rocket Lab did not disclose the customer, but speculation is focused on the defense contractor Leidos, which signed a four-launch deal with Rocket Lab last year.

Building cadence … SpaceX first launched two Falcon 9 rockets in 24 hours in 2021. This year, the company launched three Falcon 9s in a single day from pads at Cape Canaveral Space Force Station, Florida, and Vandenberg Space Force Base, California. Rocket Lab has now launched 14 Electron rockets this year, more than any other Western company other than SpaceX. “Two successful launches less than 24 hours apart from pads in different hemispheres. That’s unprecedented capability in the small launch market and one we’re immensely proud to deliver at Rocket Lab,” said Peter Beck, the company’s founder and CEO. (submitted by Ken the Bin)

Italy to reopen offshore launch site. An Italian-run space center located in Kenya will once again host rocket launches from an offshore launch platform, European Spaceflight reports. The Italian minister for enterprises, Adolfo Urso, recently announced that the country decided to move ahead with plans to again launch rockets from the Luigi Broglio Space Center near Malindi, Kenya. “The idea is to give a new, more ambitious mission to this base and use it for the launch of low-orbit microsatellites,” Urso said.

Decades of dormancy … Between 1967 and 1988, the Italian government and NASA partnered to launch nine US-made Scout rockets from the Broglio Space Center to place small satellites into orbit. The rockets lifted off from the San Marco platform, a converted oil platform in equatorial waters off the Kenyan coast. Italian officials have not said what rocket might be used once the San Marco platform is reactivated, but Italy is the leading contributor on the Vega C rocket, a solid-fueled launcher somewhat larger than the Scout. Italy will manage the reactivation of the space center, which has remained in service as a satellite tracking station, under the country’s Mattei Plan, an initiative aimed at fostering stronger economic partnerships with African nations. (submitted by Ken the Bin)

SpaceX flies same rocket twice in two weeks. Less than 14 days after its previous flight, a Falcon 9 booster took off again from Florida’s Space Coast early Monday to haul 23 more Starlink internet satellites into orbit, Spaceflight Now reports. The booster, numbered B1080 in SpaceX’s fleet of reusable rockets, made its 13th trip to space before landing on SpaceX’s floating drone ship in the Atlantic Ocean. The launch marked a turnaround of 13 days, 12 hours, and 44 minutes from this booster’s previous launch November 11, also with a batch of Starlink satellites. The previous record turnaround time between flights of the same Falcon 9 booster was 21 days.

400 and still going … SpaceX’s launch prior to this one was on Saturday night, when a Falcon 9 carried a set of Starlinks aloft from Vandenberg Space Force Base, California. The flight Saturday night was the 400th launch of a Falcon 9 rocket since 2010, and SpaceX’s 100th launch from the West Coast. (submitted by Ken the Bin)

Chinese firm launches upgraded rocket. Chinese launch startup LandSpace put two satellites into orbit late Tuesday with the first launch of an improved version of the Zhuque-2 rocket, Space News reports. The enhanced rocket, named the Zhuque-2E, replaces vernier steering thrusters with a thrust vector control system on the second stage engine, saving roughly 880 pounds (400 kilograms) in mass. The Zhuque-2E rocket is capable of placing a payload of up to 8,800 pounds (4,000 kilograms) into a polar Sun-synchronous orbit, according to LandSpace.

LandSpace in the lead … Founded in 2015, LandSpace is a leader among China’s crop of quasi-commercial launch startups. The company hasn’t launched as often as some of its competitors, but it became the first launch operator in the world to successfully reach orbit with a methane/liquid oxygen (methalox) rocket last year. Now, LandSpace has improved on its design to create the Zhuque-2E rocket, which also has a large niobium allow nozzle extension on the second stage engine for reduced weight. LandSpace also claims the Zhuque-2E is China’s first rocket to use fully supercooled propellant loading, similar to the way SpaceX loads densified propellants into its rockets to achieve higher performance. (submitted by Ken the Bin)

NASA taps Falcon Heavy for another big launch. A little more than a month after SpaceX launched NASA’s flagship Europa Clipper mission on a Falcon Heavy rocket, the space agency announced its next big interplanetary probe will also launch on a Falcon Heavy, Ars reports. What’s more, the Dragonfly mission the Falcon Heavy will launch in 2028 is powered by a plutonium power source. This will be the first time SpaceX launches a rocket with nuclear materials onboard, requiring an additional layer of safety certification by NASA. The agency’s most recent nuclear-powered spacecraft have all launched on United Launch Alliance Atlas V rockets, which are nearing retirement.

The details … Dragonfly is one of the most exciting robotic missions NASA has ever developed. The mission is to send an automated rotorcraft to explore Saturn’s largest moon, Titan, where Dragonfly will soar through a soupy atmosphere in search of organic molecules, the building blocks of life. It’s a hefty vehicle, about the size of a compact car, and much larger than NASA’s Ingenuity Mars helicopter. The launch period opens July 5, 2028, to allow Dragonfly to reach Titan in 2034. NASA is paying SpaceX $256.6 million to launch the mission on a Falcon Heavy. (submitted by Ken the Bin)

New Glenn is back on the pad. Blue Origin has raised its fully stacked New Glenn rocket on the launch pad at Cape Canaveral Space Force Station ahead of pre-launch testing, Florida Today reports. The last time this new 322-foot-tall (98-meter) rocket was visible to the public eye was in March. Since then, Blue Origin has been preparing the rocket for its inaugural launch, which could yet happen before the end of the year. Blue Origin has not announced a target launch date.

But first, more tests … Blue Origin erected the New Glenn rocket vertical on the launch pad earlier this year for ground tests, but this is the first time a flight-ready (or close to it) New Glenn has been spotted on the pad. This time, the first stage booster has its full complement of seven methane-fueled BE-4 engines. Before the first flight, Blue Origin plans to test-fire the seven BE-4 engines on the pad and conduct one or more propellant loading tests to exercise the launch team, the rocket, and ground systems before launch day.

Second Ariane 6 incoming. ArianeGroup has confirmed that the first and second stages for the second Ariane 6 flight have begun the transatlantic voyage from Europe to French Guiana aboard the sail-assisted transport ship Canopée, European Spaceflight reports. The second Ariane 6 launch, previously targeted before the end of this year, has now been delayed to no earlier than February 2025, according to Arianespace, the rocket’s commercial operator. This follows a mostly successful debut launch in July.

An important passenger … While the first Ariane 6 launch carried a cluster of small experimental satellites, the second Ariane 6 rocket will carry a critical spy satellite into orbit for the French armed forces. Shipping the core elements of the second Ariane 6 to the launch site in Kourou, French Guiana, is a significant step in the launch campaign. Once in Kourou, the stages will be connected together and rolled out to the launch pad, where technicians will install two strap-on solid rocket boosters and the payload fairing containing France’s CSO-3 military satellite.

Next three launches

Nov. 29: Soyuz-2.1a | Kondor-FKA 2 | Vostochny Cosmodrome, Russia | 21: 50 UTC

Nov. 30: Falcon 9 | Starlink 6-65 | Cape Canaveral Space Force Station, Florida | 05: 00 UTC

Nov. 30: Falcon 9 | NROL-126 | Vandenberg Space Force Base, California | 08: 08 UTC

Rocket Report: A good week for Blue Origin; Italy wants its own launch capability Read More »

Man suffers chemical burn that lasted months after squeezing limes

health, medical cases, NEJM, phytophotodermatitis, rash, Science, skin / Tim Belzer / November 27, 2024

If Margaritaville were a real place, it should definitely keep a few dermatologists on hand.

In a case of an oft-overlooked food preparation risk, a 40-year-old man showed up to an allergy clinic in Texas with a severe, burning rash on both his hands that had two days earlier. A couple of days later, it blistered. And a few weeks after that, the skin darkened and scaled. After several months, the skin on his hands finally returned to normal.

The culprit: lime juice and sunlight.

It turns out that just before developing the nasty skin eruption, the man had manually squeezed a dozen limes, then headed to an outdoor soccer game without applying sunscreen. His doctors diagnosed the man’s rash as a classic case of phytophotodermatitis, according to a case report published Wednesday in the New England Journal of Medicine.

The condition is caused by toxic substances found in plants (phyto) that react with UV light (photo) to cause a burning, blistering, scaling, pigmented skin condition (dermatitis).

Specifically, the toxic chemicals are furocoumarins, which are found in some weeds and also a range of plants used in food. Those include celery, carrot, parsley, fennel, parsnip, lime, bitter orange, lemon, grapefruit, and sweet orange. Furocoumarins include chemicals with linear structures, psoralens, and angular structures, called angelicins, though not all of them are toxic.

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What fossilized dino feces can tell us about their rise to dominance

coprolites, dinosaurs, evolutionary biology, food webs, fossilized feces, Jurassic, paleontology, Science, Triassic / Paul Patrick / November 27, 2024

Paleontologists have long puzzled over how the dinosaurs—originally relatively small and of minor importance to the broader ecosystem—evolved to become the dominant species some 30 million years later. Fossilized feces and vomit from dinosaurs might hold important clues to how and why this evolutionary milestone came about, according to a new paper published in the journal Nature.

Co-author Martin Qvarnström, an evolutionary biologist with Uppsala University in Sweden, and his collaborators studied trace fossils known as bromalites, a designation that includes coprolites as well as vomit or other fossilized matter from an organism’s digestive tract. As previously reported, coprolites aren’t quite the same as paleofeces, which retain a lot of organic components that can be reconstituted and analyzed for chemical properties. Coprolites are fossils, so most organic components have been replaced by mineral deposits like silicate and calcium carbonates.

For archaeologists keen on learning more about the health and diet of past populations—as well as how certain parasites evolved in the evolutionary history of the microbiome—coprolites and paleofeces can be a veritable goldmine of information. For instance, in 2021 we reported on an analysis of preserved paleo-poop revealing that ancient Iron Age miners in what is now Austria were fond of beer and blue cheese.

If a coprolite contains bone fragments, chances are the animal who excreted it was a carnivore, and tooth marks on those fragments can tell us something about how the animal may have eaten its prey. The size and shape of coprolites can also yield useful insights. If a coprolite is spiral-shaped, for instance, it might have been excreted by an ancient shark, since some modern fish (like sharks) have spiral-shaped intestines.

A tale of two models

Excavations in the Late Triassic locality at Lisowice, Poland. The site yielded a large number of coprolites of predators and herbivores. Credit: Krystian Balanda

Qvarnström et al. were keen to test two competing hypotheses about the dinosaurs’ rise to dominance from the Late Triassic Period (237 million to 201 million years ago) to the onset of the Jurassic Period between 201 million to 145 million years ago. “No single hypothesis seems capable of explaining the rise of dinosaurs fully and critical questions about how dinosaurs established their dynasty on land remain largely unanswered,” the authors wrote about their research objectives.

One hypothesis cites evolutionary competition—the traditional “competitive replacement” model—as a driving factor, in which dinosaurs were better equipped to survive thanks to superior physiologies, anatomical adaptations, and feeding habits. Alternatively the “opportunistic replacement” model suggests that the dinosaurs were better able to adapt to a rapidly changing environment brought about by random processes—volcanic eruptions, climate change, or other catastrophic events that led to the decline and/or extinction of other species.

What fossilized dino feces can tell us about their rise to dominance Read More »

Teaching a drone to fly without a vertical rudder

Biomechanics, birds, Drones, engineering, flight, mechanical engineering, Science / Tim Belzer / November 27, 2024

We can get a drone to fly like a pigeon, but we needed to use feathers to do it.

Pigeons manage to get vertical without using a vertical tail. Credit: HamidEbrahimi

Most airplanes in the world have vertical tails or rudders to prevent Dutch roll instabilities, a combination of yawing and sideways motions with rolling that looks a bit like the movements of a skater. Unfortunately, a vertical tail adds weight and generates drag, which reduces fuel efficiency in passenger airliners. It also increases the radar signature, which is something you want to keep as low as possible in a military aircraft.

In the B-2 stealth bomber, one of the very few rudderless airplanes, Dutch roll instabilities are dealt with using drag flaps positioned at the tips of its wings, which can split and open to make one wing generate more drag than the other and thus laterally stabilize the machine. “But it is not really an efficient way to solve this problem,” says David Lentink, an aerospace engineer and a biologist at the University of Groningen, Netherlands. “The efficient way is solving it by generating lift instead of drag. This is something birds do.”

Lentink led the study aimed at better understanding birds’ rudderless flight mechanics.

Automatic airplanes

Birds flight involves near-constant turbulence—“When they fly around buildings, near trees, near rocks, near cliffs,” Lentink says. The leading hypothesis on how they manage this in a seemingly graceful, effortless manner was suggested by a German scientist named Franz Groebbels. He argued that birds’ ability relied on their reflexes. When he held a bird in his hands, he noticed that its tail would flip down when the bird was pitched up and down, and when the bird was moved left and right, its wings also responded to movement by extending left and right asymmetrically. “Another reason to think reflexes matter is comparing this to our own human locomotion—when we stumble, it is a reflex that saves us from falling,” Lentink claims.

Groebbels’ intuition about birds’ reflexes being responsible for flight stabilization was later backed by neuroscience. The movements of birds’ wings and muscles were recorded and found to be proportional to the extent that the bird was pitched or rolled. The hypothesis, however, was extremely difficult to test with a flying bird—all the experiments aimed at confirming it have been done on birds that were held in place. Another challenge was determining if those wing and tail movements were reflexive or voluntary.

“I think one pretty cool thing is that Groebbels wrote his paper back in 1929, long before autopilot systems or autonomous flight were invented, and yet he said that birds flew like automatic airplanes,” Lentink says. To figure out if he was right, Lentink and his colleagues started with the Groebbels’s analogy but worked their way backward—they started building autonomous airplanes designed to look and fly like birds.

Reverse-engineering pigeons

The first flying robot Lentink’s team built was called the Tailbot. It had fixed wings and a very sophisticated tail that could move with five actuated degrees of freedom. “It could spread—furl and unfurl—move up and down, move sideways, even asymmetrically if necessary, and tilt. It could do everything a bird’s tail can,” Lentink explains. The team put this robot in a wind tunnel that simulated turbulent flight and fine-tuned a controller that adjusted the tail’s position in response to changes in the robot’s body position, mimicking reflexes observed in real pigeons.

“We found that this reflexes controller that managed the tail’s movement worked and stabilized the robot in the wind tunnel. But when we took it outdoors, results were disappointing. It actually ended up crashing,” Lentink says. Given that relying on a morphing tail alone was not enough, the team built another robot called PigeonBot II, which added pigeon-like morphing wings.

Each wing could be independently tucked or extended. Combined with the morphing tail and nine servomotors—two per wing and five in the tail—the robot weighed around 300 grams, which is around the weight of a real pigeon. Reflexes were managed by the same controller that was modified to manage wing motions as well.

To enable autonomous flight, the team fitted the robot with two propellers and an off-the-shelf drone autopilot called Pixracer. The problem with the autopilot, though, was that it was designed for conventional controls you use in quadcopter drones. “We put an Arduino between the autopilot and the robot that translated autopilot commands to the morphing tail and wings’ motions of the robot,” Lentink says.

The Pigeon II passed the outdoor flying test. It could take off, land, and fly entirely on its own or with an operator issuing high-level commands like go up, go down, turn left, or turn right. Flight stabilization relied entirely on bird-like reflexes and worked well. But there was one thing electronics could not re-create: their robots used real pigeon feathers. “We used them because with current technology it is impossible to create structures that are as lightweight, as stiff, and as complex at the same time,” Lentink says.

Feathery marvels

Birds’ feathers appear simple, but they really are extremely advanced pieces of aerospace hardware. Their complexity starts with nanoscale features. “Feathers have 10-micron 3D hooks on their surface that prevent them from going too far apart. It is the only one-sided Velcro system in the world. This is something that has never been engineered, and there is nothing like this elsewhere in nature,” Lentink says. Those nanoscale hooks, when locked in, can bear loads reaching up to 20 grams.

Then there are macroscale properties. Feathers are not like aluminum structures that have one bending stiffness, one torque stiffness, and that’s it. “They are very stiff in one direction and very soft in another direction, but not soft in a weak way—they can bear significant loads,” Lentink says.

His team attempted to make artificial feathers with carbon fiber, but they couldn’t create anything as lightweight as a real feather. “I don’t know of any 3D printer that could start with 10-micron nanoscale features and work all the way up to macro-scale structures that can be 20 centimeters long,” Lentink says. His team also discovered that pigeon’s feathers could filter out a lot of turbulence perturbations on their own. “It wasn’t just the form of the wing,” Lentink claims.

Lentink estimates that a research program aimed at developing aerospace materials even remotely comparable to feathers could take up to 20 years. But does this mean his whole concept of using reflex-based controllers to solve rudderless flight hangs solely on successfully reverse-engineering a pigeon’s feather? Not really.

Pigeon bombers?

The team thinks it could be possible to build airplanes that emulate the way birds stabilize rudderless flight using readily available materials. “Based on our experiments, we know what wing and tail shapes are needed and how to control them. And we can see if we can create the same effect in a more conventional way with the same types of forces and moments,” Lentink says. He suspects that developing entirely new materials with feather-like properties would only become necessary if the conventional approach bumps into some insurmountable roadblocks and fails.

“In aerospace engineering, you’ve got to try things out. But now we know it is worth doing,” Lentink claims. And he says military aviation ought to be the first to attempt it because the risk is more tolerable there. “New technologies are often first tried in the military, and we want to be transparent about it,” he says. Implementing bird-like rudderless flight stabilization in passenger airliners, which are usually designed in a very conservative fashion, would take a lot more research, “It may take easily take 15 years or more before this technology is ready to such level that we’d have passengers fly with it,” Lentink claims.

Still, he says there is still much we can learn from studying birds. “We know less about bird’s flight than most people think we know. There is a gap between what airplanes can do and what birds can do. I am trying to bridge this gap by better understanding how birds fly,” Lentink adds.

Science Robotics, 2024. DOI: 10.1126/scirobotics.ado4535

Jacek Krywko is a freelance science and technology writer who covers space exploration, artificial intelligence research, computer science, and all sorts of engineering wizardry.

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Licking this “lollipop” will let you taste virtual flavors

augmented reality, extended reality, haptic interfaces, Human-computer interface, Science, virtual reality / Tim Belzer / November 26, 2024

Demonstrating lollipop user interface to simulate taste in virtual and augmented reality environments. Credit: Lu et al, 2024/PNAS

Virtual reality (VR) technology has long sought to incorporate the human senses into virtual and mixed-reality environments. In addition to sight and sound, researchers have been trying to add the sensation of human touch and smell via various user interfaces, as well as taste. But the latter has proved to be quite challenging. A team of Hong Kong scientists has now developed a handheld user interface shaped like a lollipop capable of re-creating several different flavors in a virtual environment, according to a new paper published in the Proceedings of the National Academy of Sciences (PNAS).

It’s well established that human taste consists of sweet, salty, sour, bitter, and umami—five basic flavors induced by chemical stimulation of the tongue and, to a lesser extent, in parts of the pharynx, larynx, and epiglottis. Recreating those sensations in VR has resulted in a handful of attempts at a flavor user interface, relying on such mechanisms as chemical, thermal, and electrical stimulation, as well as iontophoresis.

The chemical approach usually involves applying flavoring chemicals directly onto the tongue, but this requires room for bulk storage of said chemicals, and there is a long delay time that is not ideal for VR applications. Thermal variations applied directly to the tongue can stimulate taste sensations but require a complicated system incorporating a cooling subsystem and temperature sensors, among other components.

The most mainstream method is electrical stimulation, in which the five basic flavors are simulated by varying the frequency, intensity, and direction of electrical signals on the tongue. But this method requires placing electrode patches on or near the tongue, which is awkward, and the method is prone to taste biases.

So Yiming Liu of City University of Hong Kong and co-authors opted to work with iontophoresis, in which stable taste feedback is achieved by using ions flowing through biologically safe hydrogels to transport flavor chemicals. This method is safe, requires low power consumption, allows for precise taste feedback, and offers a more natural human-machine interface. Liu et al. improved on recent advances in this area by developing their portable lollipop-shaped user interface device, which also improves flavor quality and consistency.

Licking this “lollipop” will let you taste virtual flavors Read More »

NASA awards SpaceX a contract for one of the few things it hasn’t done yet

dragonfly, falcon heavy, launch, NASA, nuclear, planetary science, Saturn, Science, solar system, Space, spacex, Titan / Kris Guyer / November 26, 2024

Notably, the Dragonfly launch was one of the first times United Launch Alliance has been eligible to bid its new Vulcan rocket for a NASA launch contract. NASA officials gave the green light for the Vulcan rocket to compete head-to-head with SpaceX’s Falcon 9 and Falcon Heavy after ULA’s new launcher had a successful debut launch earlier this year. With this competition, SpaceX came out on top.

A half-life of 88 years

NASA’s policy for new space missions is to use solar power whenever possible. For example, Europa Clipper was originally supposed to use a nuclear power generator, but engineers devised a way for the spacecraft to use expansive solar panels to capture enough sunlight to produce electricity, even at Jupiter’s vast distance from the Sun.

But there are some missions where this isn’t feasible. One of these is Dragonfly, which will soar through the soupy nitrogen-methane atmosphere of Titan. Saturn’s largest moon is shrouded in cloud cover, and Titan is nearly 10 times farther from the Sun than Earth, so its surface is comparatively dim.

The Dragonfly mission, seen here in an artist’s concept, is slated to launch no earlier than 2027 on a mission to explore Saturn’s moon Titan. Credit: NASA/JHUAPL/Steve Gribben

Dragonfly will launch with about 10.6 pounds (4.8 kilograms) of plutonium-238 to fuel its power generator. Plutonium-238 has a half-life of 88 years. With no moving parts, RTGs have proven quite reliable, powering spacecraft for many decades. NASA’s twin Voyager probes are approaching 50 years since launch.

The Dragonfly rotorcraft will launch cocooned inside a transit module and entry capsule, then descend under parachute through Titan’s atmosphere, which is four times denser than Earth’s. Finally, Dragonfly will detach from its descent module and activate its eight rotors to reach a safe landing.

Once on Titan, Dragonfly is designed to hop from place to place on numerous flights, exploring environments rich in organic molecules, the building blocks of life. This is one of NASA’s most exciting, and daring, robotic missions of all time.

After launching from NASA’s Kennedy Space Center in Florida in July 2028, it will take Dragonfly about six years to reach Titan. When NASA selected the Dragonfly mission to begin development in 2019, the agency hoped to launch the mission in 2026. NASA later directed Dragonfly managers to target a launch in 2027, and then 2028, requiring the mission to change from a medium-lift to a heavy-lift rocket.

Dragonfly has also faced rising costs NASA blames on the COVID-19 pandemic and supply chain issues and an in-depth redesign since the mission’s selection in 2019. Collectively, these issues caused Dragonfly’s total budget to grow to $3.35 billion, more than double its initial projected cost.

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