In the social media age, there is little doubt about who is the star of the animal kingdom. Cats rule the screens just as their cousins, the lions, rule the savanna. Thanks to Erwin Schrödinger, this feline also has a place of honor in the history of physics. And it was Eme the cat that inspired Anxo Biasi, researcher at the Instituto Galego de Física de Altas Enerxías (IGFAE), to publish an article in the American Journal of Physics.

In this paper, Anxo presents the equation of cat motion. “This article aims to bring physics closer to non-experts, offering a pleasant example through which it is possible to understand several concepts of classical mechanics. To do so, an equation is constructed that models the behavior of a cat in the presence of a person, considering the former as a point particle that moves in a potential induced by the human,” he summarizes.

Explaining physics with cats

Anxo recently joined the IGFAE, a joint center of the University of Santiago de Compostela (USC) and the regional government from Galicia (Spain), through the Junior Leader program of La Caixa, from the Physics Department of the École Normale Supérieure de Paris.

At the IGFAE, where he has already completed his doctoral thesis, he will develop his line of research in non-linear evolution equations, at the intersection between physics and mathematics, joining the String Theory and related fields team.

The idea for the article came about to “communicate physics in a fun way, making it more attractive to students,” he says. And so, what seemed, to some extent, a joke, gradually took on an academic form.

“This started as a playful idea for Fool’s Day, inspired by the funny papers presented by some researchers. However, I soon realized that this story I created could be of great help to physics students. The story is very conceptually loaded, but it introduces it in a fun way using an example that arouses great curiosity: a cat!”

And how is the equation of cat movement built?

Anxo starts from seven dynamics, or patterns, extracted from his day-to-day experience with Eme, and uses the hypothesis that “cats behave as if they perceive a force around a person.”

In this way, the article states that the seven dynamics aforementioned can be modeled, as a first approximation, by considering the cat as a point particle that obeys Newtonian mechanics.

The cat experiences a “force” linked to an external potential (induced by the presence of a person) where x(t) ∈ R represents the position of the cat at time t with respect to the person located at x = 0. Thus, m > 0 is the mass of the cat, and ϵ > 0 is the coefficient of friction to consider the cat’s fatigue. The result is, therefore, this equation:

Starting from this formula, and through the analysis of feline motion, it is possible to show how the equations themselves are constructed.

“The work demonstrates, in an entertaining way, the mental process followed in the construction of physics models, which is rarely detailed in books. For example, patterns of movement (or non-movement) are analyzed, derived from the fact that cats tend not to come when called, are easily distracted, or tend to stay longer on the lap of their favorite person.”

All these calculations are approached in an engaging and fun way. “We don’t always need to tackle the deepest and most challenging mysteries of the universe; sometimes we can just relax and use the power of physics to explain everyday life—it’s really funny!”, Anxo says.

In this way, “the cat-human interaction model brings physics closer to non-experts, demonstrating through a curious and familiar situation the reasoning behind the construction of physical models,” he summarizes.

Purring and zoomies analysis

The paper focuses on the analysis of the characteristic feline purr. His proposal is that this reaction is a stabilization mechanism, which is fed back by the interaction between the cat and its human companion.

“It is proposed that when a cat is being stroked and starts to purr, people tend to feel the impulse to continue stroking it, thus reinforcing the stability of the process.”

This stabilization is also reinforced by the fact that the exchange of affection between purring and stroking temporarily strengthens the bond between cat and human.

The study also considers periods of frenetic random activity, known as FRAP or “zoomies,” when cats move at full speed from one place to another, usually at night. The paper discusses how, in this case, the equation requires a random component to model these periods, built into the formula as an external “forcing.” This adds some randomness necessary to model these cat “outbursts,” which to some extent could be adjusted to the particularities of everyone.

Educational use

In addition to its playful approach, Anxo stresses that this article “is intended for use in introductory courses in classical mechanics, to demonstrate how apparently complex and unrelated behavior can be explained by simple laws.”

It does so by showing “a series of dynamics that are easy to visualize, reducing the need for abstraction,” and presents “an equation with different terms, covering the fundamentals of classical mechanics.”

A popular new strategy for combating misinformation doesn’t by itself help people distinguish truth from falsehood but improves when paired with reminders to focus on accuracy, finds new Cornell University-led research supported by Google.

Psychological inoculation, a form of “prebunking” intended to help people identify and refute false or misleading information, uses short videos in place of ads to highlight manipulative techniques common to misinformation, such as emotional language, false dichotomies and scapegoating. The strategy has already been deployed to millions of users of YouTube, Facebook and other platforms, and could be utilized after the U.S. presidential election.

In a series of studies involving nearly 7,300 online participants, an inoculation video about emotional language improved recognition of that technique—but did not improve people’s ability to discern true headlines from false ones, the researchers found. Participants’ ability to identify true information improved when the video was bookended with video clips prompting them to think about whether content was accurate, suggesting a combined approach could be more effective, the researchers said.

“If you just tell people to watch out for things like emotional language, they’ll disbelieve true things that have emotional language as much as false things that have emotional language,” said Gordon Pennycook, associate professor of psychology. “Encouragingly, we found some synergy between these two approaches, and that means we may be able to develop more effective interventions.”

Pennycook is the first author of “Inoculation and Accuracy Prompting Increase Accuracy Discernment in Combination but Not Alone” in Nature Human Behaviour.

Prior studies involving members of the research team showed that inoculation videos helped people identify manipulative techniques in sample tweets. That raised hopes that a relatively simple intervention could be implemented on a large scale to “immunize” populations against potentially viral misinformation.

The new study investigated whether inoculation’s benefits carried over to more real-world conditions by helping people assess whether information was true or not.

In three initial studies, participants watched the same emotional language video used in the earlier study, which warns viewers to be wary, for example, of headlines referencing a “horrific” accident rather than a “serious” one, or a “disgusting” (versus “disagreeable”) ruling. They then reviewed real headlines—some true, some false—presented in one of two versions the researchers designed: either emotionally neutral or using charged language that could evoke fear or anger.

For example, a true, low-emotion headline read, “NYC wants to ‘end the COVID era,’ declares vaccine as a requirement for its workers.” The evocative version read, “Thousands being forced to take the jab: NYC mandates vaccines for its workers.”

Replicating the earlier work, the less than two-minute inoculation video helped study participants flag manipulative content, particularly in high-emotion headlines. But that didn’t make them better at judging which information was accurate—even in the context most favorable for inoculation, when all false headlines contained highly emotional language, and all true headlines were neutral.

“When the task is made more difficult by intermixing actual true or false claims,” the authors wrote, “the video appears to lose its effectiveness as an ‘inoculation against misinformation.'”

A final pair of studies explored the potential benefits of so-called accuracy prompts—simple reminders about the importance of considering accuracy and the threat of misinformation. Like inoculation, accuracy prompts alone proved ineffective for helping people identify true versus false claims (unlike their past use where they successfully improved the news people share). But when the accuracy prompts were sandwiched around the inoculation video, study participants’ identification of true headlines (but not false ones) improved significantly, by up to 10%.

“This shows that combining two techniques that can be readily deployed at scale can boost people’s skills to avoid being misled,” said Stephan Lewandowsky, professor at the University of Bristol, England, and a co-author of the research.

The results have significant implications for the growing field of designing misinformation interventions, the researchers said, highlighting for industry actors and policymakers the importance of testing and deploying multiple interventions in tandem.

“If you’re going to run these interventions, you should probably begin them with a base reminder about accuracy,” Pennycook said. “Just getting people to think more about whether things are true will carry over—at least in the short term—to what they’re seeing and choices about what they would share online.”

In addition to Pennycook and Lewandowsky, co-authors are Adam Berinsky and David Rand ’04, professors at the Massachusetts Institute of Technology; Puneet Bhargava, a graduate student at the University of Pennsylvania; and Hause Lin, a postdoctoral researcher at MIT.

Cratons are fascinating yet enigmatic geological formations. Known to be relatively stable portions of the Earth’s continental crust, cratons have remained largely unchanged for billions of years. Although cratons have survived many geological events, some are undergoing decratonization—a process characterized by their deformation and eventual destruction.

For example, the North China Craton (NCC), an ancient continental crust block, is known to have begun extensive decratonization during the Mesozoic era, largely due to tectonic and geochemical modifications and destabilization of its base (or “keel”). However, explaining the mechanisms behind these complex geological transformations has proven difficult with existing techniques and current understanding.

In a recent study published in Nature Geoscience, a research team led by Professor Shaofeng Liu from China University of Geosciences (Beijing) successfully addressed this knowledge gap by developing a computational model supported by extensive geological, geophysical, and empirical geochemical data that explains the puzzling deformation of the NCC.

Specifically, the developed model focuses on the subduction of the Izanagi plate beneath the Eurasian plate, where the NCC is located, as the reason underlying the observed decratonization.

The researchers compared several possible subducted plate geometries using earthquake seismicity and basin stratigraphy evidence to narrow down potential reconstructions. Finally, using their geodynamic mantle-flow model, they simulated the full extent of the subduction process and validated the predictions empirically.

Their analysis explains the decratonization of the NCC in three phases. First, the Izanagi plate underwent initial subduction and slid beneath the Eurasian plate. However, instead of progressing downward, the Izanagi plate flattened and started moving parallel to the Eurasian plate, in a process called flat-slab subduction. Fluids from the subducted plate altered the NCC’s keel above, initiating its destruction. In addition, squeezing forces caused other deformations, such as thrusting, craton thickening, and surface uplift.

Interestingly, there was then a rollback process, as a result of which the subducted plate steepened again and progressed deeper below the Eurasian plate, reaching the upper-lower mantle interface and undergoing horizontal subduction into the mantle transition zone. This rollback caused extensional deformation, resulting in thinning of the lithosphere and the formation of rift basins with surface topographic lowing on the craton.

Additionally, a large region of upper mantle material, known as a “large mantle wedge,” developed between the advancing slab and the craton, leading to convection that can induce intense metasomatism and partial melting along with heating and erosion at the base of the sub-craton, as well as magmatism.

Prof. Liu says, “We successfully developed a new mantle-flow model incorporating flat-slab and rollback subduction, which aligns with surface geological evolution and the present-day mantle slab structure.

“Interestingly, our validated model can effectively describe the space–time dynamics and topographic response of mantle slab subduction over time.”

Given that cratons contain mineral and rare-earth element deposits with immense value for technological applications, understanding the life cycle of cratons is important from both an academic and a practical standpoint. Building on these insights, further inquiries into the geological history of our planet will hopefully lead us to a deeper understanding of geological processes like decratonization, revealing paths towards a more sustainable future.

New studies about the Thwaites Glacier, also called the “Doomsday Glacier,” have sparked a conversation about geoengineering as a climate change solution.

One study published in May and led by University of California Irvine and University of Waterloo scientists found that warming tidal currents are accelerating the Thwaites’ melting and leading to quicker retreat than models have predicted, while another study published in August and led by researchers at Dartmouth College and University of Edinburgh found that the Thwaites may be less vulnerable to instability and collapse than previously thought.

With the fate of the Thwaites still uncertain, some scientists and engineers are turning to controversial ideas on how to alter the environment to slow glacier melt.

Understanding accelerated melt from warm tidal currents

The Thwaites Glacier is one of a line of glaciers sitting along the marine-facing rim of the West Antarctic Ice Sheet (WAIS)—a massive bowl of ice nearly three times the size of Texas sitting in a basin below sea level in Western Antarctica. The only bulwarks that prevent the ocean from filling the basin and melting or dislodging the ice are the glaciers.

This situation has led scientists and the media to term the Thwaites—a glacier larger than the entire state of Florida—the “Doomsday Glacier” because its breach would allow warmer ocean waters to melt the WAIS and raise sea levels by nearly 11 feet. This would put many large coastal cities and small island nations at extreme risk.

The Thwaites is retreating rapidly due to climate change, and already accounts for 4% of sea level rise on Earth, losing 50 billion tons of ice each year. Due to the catastrophic sea level rise that would occur, the breaching of the Thwaites and subsequent dislodgement of the WAIS are what’s known as a tipping point in climate science.

A tipping point is when crossing a critical threshold—in this case, atmospheric and oceanic warming—leads to large, accelerating, and irreversible changes in the climate system. The melting of the Thwaites Glacier would lead to the collapse of the WAIS which would in turn cause irreversible sea level rise that could endanger millions of people and accelerate warming of other ice.

The PNAS study led by UC Irvine and University of Waterloo researchers used high-resolution satellite images and hydrological data to identify areas where warm tidal currents were flowing under the ice and causing faster melt. Understanding the melt rate is critical for predicting sea level rise according to Christine Dow.

Dow, an associate professor of glaciology at the University of Waterloo and a co-author of the study, said in an interview with Scientific American, “We were hoping it would take a hundred, 500 years to lose that ice. A big concern right now is if it happens much faster than that.”

However, there is some hope for the WAIS. The study by Dartmouth College and University of Edinburgh researchers found that the Thwaites is not as susceptible to a process called marine ice cliff instability (MICI) as previously thought.

The MICI hypothesis suggests that tall ice cliffs formed by retreating glaciers are unstable and collapse more easily, but this study showed that thinning of the Thwaites could actually reduce the calving rate and stabilize ice cliffs, highlighting the need for better models when making predictions about the WAIS.

Debate over geoengineering as a solution

Faced with uncertainty and the potential of rapid and extreme sea level rise if the Thwaites melts faster than expected, some scientists are turning to glacial geoengineering—the process of using technology and infrastructure to slow or stop glacier retreat even as global temperatures increase—as a potential solution.

A group of glaciologists affiliated with the Climate Systems Engineering Initiative at the University of Chicago released a report in July of this year calling for more research into glacier geoengineering in response to the threats posed by rapidly retreating glaciers.

John Moore, a professor with the Arctic Center at the University of Lapland and co-author of the report, explained the necessity of starting this work now to UChicago News, saying, “it will take 15 to 30 years for us to understand enough to recommend or rule out any [glacier geoengineering] interventions,” meaning they must start immediately to be prepared.

Some of the ideas for protecting the Thwaites and other marine-terminating glaciers like it are considered radical, including creating giant submarine curtains that would at least partially prevent warm tidal currents from reaching the glacier ice. The curtains could be made of fabric or even bubbles if a pipe with holes drilled into it and air pumped through it could be placed between the Thwaites and the warm water.

Glacial geoengineering interventions like these could be extremely useful if implemented correctly, according to Gernot Wagner, a climate economist in the Columbia Climate School. In an interview with GlacierHub, Wagner said, “for some polar tipping points like Arctic sea ice and the WAIS, glacial geoengineering seems to be the only way for us to more or less guarantee that we can address these tipping points.”

However, many of these ideas have faced opposition from glaciologists and climate scientists who claim that they would be difficult or impossible to achieve and draw focus away from the more necessary conversation of reducing carbon emissions. By relying too much on strategies like geoengineering, these scientists argue we may fail to act to curb emissions.

Wagner takes a nuanced approach. His initial reaction to the idea of installing curtains was “that it seems crazy. Geoengineering options like these curtains could detract from the need to cut emissions.” On the flipside, he said, “you can use it as a push to say, ‘wait, if serious people are talking about [using curtains] as a solution, maybe we should be taking it more seriously and cutting emissions much more.'”

As we creep closer to climate tipping points like the melting of the Thwaites Glacier, many believe geoengineering has the potential to be a powerful tool so long as it is not treated as a silver bullet. As Wagner stated, “When we talk about glacial geoengineering, we need to tell the truth, which is that it’s not a solution to climate change—at best, it’s a painkiller. It allows us to get out of bed and do what is necessary to address the underlying illness while taking the edge off the worst of the pain.

“[But] geoengineering doesn’t solve anything, so we need to use the time it gives us to address emissions.”

This story is republished courtesy of Earth Institute, Columbia University http://blogs.ei.columbia.edu.