Science

A team of astrophysicists from several institutions in Italy, working with a colleague in the U.S., has found that aliphatic hydrocarbons observed on Ceres’ surface have short lifetimes, suggesting they likely appeared there within the last 10 million years.

In their paper published in the journal Science Advances, the group describes how they conducted experiments in their lab designed to mimic conditions on Ceres.

Ceres is the largest body in the middle of the main asteroid belt that lies between the orbits of Jupiter and Mars. It was initially classified as an asteroid but more recently has been upgraded to dwarf planet.

Prior study of Ceres, much of which came from NASA’s Dawn space mission, has shown there is organic material on its surface. In this new effort, the researchers investigated the history of aliphatic organics (AOs) on the surface.

AOs are a hydrocarbon class that includes alkenes, alkanes and alkynes—some of them have been observed on Ceres’s surface circling a large crater. The team wanted to know how long the AOs have been there. To find out, they created a batch of material meant to mimic the AO material on Ceres as closely as possible.

They then fired ultraviolet radiation and other ions at the sample as an attempt to mimic the conditions faced on Ceres. Prior research has shown that such space-weathering can break down organic compounds.

After the bombardment, the researchers studied the sample, looking for signs of degradation. They found evidence showing that such a breakdown would occur relatively quickly. Doing the math showed that it would break down considerably over the course of just 10 million years. This, they note, suggests that the AOs spotted on Ceres could not have been there any longer than that.

Prior research has shown that the organic materials on the surface of Ceres likely formed deep inside the dwarf planet. The new findings suggest that such mixing occurred relatively recently. The researchers theorize that the AOs on the surface were likely produced by Ceres’s internal ocean.

© 2024 Science X Network

People around the globe often depend on informal financial arrangements, borrowing and lending money through social networks. Understanding this sheds light on local economies and helps fight poverty.

Now, a study co-authored by an MIT economist illuminates a striking case of informal finance: In East Africa, money moves in very different patterns depending on whether local societies are structured around family units or age-based groups.

That is, while much of the world uses the extended family as a basic social unit, hundreds of millions of people live in societies with stronger age-based cohorts. In these cases, people are initiated into adulthood together and maintain closer social ties with each other than with extended family. That affects their finances, too.

“We found there are major impacts in that social structure really does matter for how people form financial ties,” says Jacob Moscona, an MIT economist and co-author of the newly published study.

He adds, “In age-based societies when someone gets a cash transfer, the money flows in a big way to other members of their age cohort but not to other [younger or older] members of an extended family. And you see the exact opposite pattern in kin-based groups, where money is transferred within the family but not the age cohort.”

This leads to measurable health effects. In kin-based societies, grandparents often share their pension payments with grandchildren. In Uganda, the study reveals, an additional year of pension payments to a senior citizen in a kin-based society reduces the likelihood of child malnourishment by 5.5%, compared to an age-based society where payments are less likely to move across generations.

The paper, “Age Set versus Kin: Culture and Financial Ties in East Africa,” is published in the September issue of the American Economic Review. The authors are Moscona, the 3M Career Development Assistant Professor of Economics in MIT’s Department of Economics; and Awa Ambra Seck, an assistant professor at Harvard Business School.

Studying informal financial arrangements has long been an important research domain for economists. MIT Professor Robert Townsend, for one, helped advance this area of scholarship with innovative studies of finances in rural Thailand.

At the same time, the specific matter of analyzing how age-based social groups function, in comparison to the more common kin-based groups, has tended to be addressed more by anthropologists than economists.

Among the Maasai people in Northern Kenya, for example, anthropologists have observed that age-group friends have closer ties to each other than anyone apart from a spouse and children. Maasai age-group cohorts frequently share food and lodging, and more extensively than they do even with siblings. The current study adds economic data points to this body of knowledge.

To conduct the research, the scholars first analyzed the Kenyan government’s Hunger Safety Net Program (HSNP), a cash transfer project initiated in 2009 covering 48 locations in Northern Kenya. The program included both age-based and kin-based social groups, allowing for a comparison of its effects.

In age-based societies, the study shows, there was a spillover in spending by HSNP recipients on others in the age cohort, with zero additional cash flows to those in other generations; in kin-based societies, they also found a spillover across generations, but without informal cash flows otherwise.

In Uganda, where both kin-based and age-based societies exist, the researchers studied the national roll-out of the Senior Citizen Grant (SCG) program, initiated in 2011, which consists of a monthly cash transfer to seniors of about $7.50, equivalent to roughly 20% of per-capita spending. Similar programs exist or are being rolled out across sub-Saharan Africa, including in regions where age-based organization is common.

Here again, the researchers found financial flows aligned to kin-based and age-based social ties. In particular, they show that the pension program had large positive effects on child nutrition in kin-based households, where ties across generations are strong; the team found zero evidence of these effects in age-based societies.

“These policies had vastly different effects on these two groups, on account of the very different structure of financial ties,” Moscona says.

To Moscona, there are at least two large reasons to evaluate the variation between these financial flows: understanding society more thoroughly and rethinking how to design social programs in these circumstances.

“It’s telling us something about how the world works, that social structure is really important for shaping these [financial] relationships,” Moscona says. “But it also has a big potential impact on policy.”

After all, if a social policy is designed to help limit childhood poverty, or senior poverty, experts will want to know how the informal flow of cash in a society interacts with it. The current study shows that understanding social structure should be a high-order concern for making policies more effective.

“In these two ways of organizing society, different people are on average more vulnerable,” Moscona says. “In the kin-based groups, because the young and the old share with each other, you don’t see as much inequality across generations.

“But in age-based groups, the young and the old are left systematically more vulnerable. And in kin-based groups, some entire families are doing much worse than others, while in age-based societies the age sets often cut across lineages or extended families, making them more equal. That’s worth considering if you’re thinking about poverty reduction.”

This story is republished courtesy of MIT News (web.mit.edu/newsoffice/), a popular site that covers news about MIT research, innovation and teaching.

Technology is often seen as a threat to democracy, with the surge in AI capabilities the latest big concern.

This historic year of elections has put the complex relationship between technology and democracy on full display.

All eyes are currently on the upcoming elections in the U.S., with recent assassination attempts highlighting the deep divisions in the world’s most powerful democracy.

Many have blamed social media for supercharging this polarization, with AI increasingly used to spread disinformation on these platforms.

But, instead of dividing, could “pro-democratic” social technologies help communities work through difficult issues like climate change?

I’m exploring how digital tools can support democracy by helping crowdsource ideas, understand lines of division, and find points of consensus that bridge them.

These trials are inspired by innovations in digital democracy in Taiwan, another democratic society under threat.

Lessons from Taiwan

Back in January, many held grave concerns about technology being weaponized to spread disinformation and influence the general election in Taiwan.

But these threats were fended off with overwhelming success, largely thanks to thoughtful and socially-oriented uses of digital technology.

Digital tools—created and used collaboratively by citizens, civil society and government—were also a pillar of Taiwan’s response to the COVID-19 crisis, which was celebrated for achieving among the lowest mortality rates in the world without imposing lockdowns.

Examples include the use of social media to “inoculate” misinformation through funny memes, and an app created by civic hackers to show live mask availability in pharmacies.

This resilience to threats shows the power of the digital democracy ecosystem that has flourished in Taiwan over the past decade, according to a new book, “Plurality,” showcasing the island as a model for the future of collaborative technology and democracy.

Speaking at the National Press Club during a recent visit to Australia, one of the authors, Audrey Tang—civic hacker turned Taiwan’s first digital minister—explained the ethos underpinning these efforts: that the best way to protect democracy is to keep improving it.

Polis—a ‘pro-social’ platform

Tang says we shouldn’t be surprised when people start “screaming at each other” in political discussions on platforms like Facebook or X/Twitter because they are the digital equivalent of having a town hall discussion in a nightclub.

Polis is something different—an open-source digital democracy tool that Tang calls a “pro-social social media” platform.

To protect against trolling, there is no “reply” button—when you see a comment, you just vote (agree, disagree or pass) and can submit your own comment(s) separately if you want to.

In Taiwan, Polis has been used to find a “rough consensus” on issues like Uber regulation and AI development, inspiring many to wonder if these approaches could be used and built upon in other contexts around the world.

When I first heard these stories about five years ago, I was working with colleagues to support community well-being in the face of climate change and disasters. And we began to wonder:

Given the many urgent, complex issues facing communities across Australia due to climate change, these are compelling possibilities. This has been the motivation for my doctoral research.

Lessons from climate change pilots in Australia

In our first pilot using Polis in Australia in 2022, we ran a consultation at the University of Melbourne about the climate impacts of staff flying—a thorny issue especially in countries like Australia that are far away from conference hubs in the U.S. and Europe.

We posed a single question: What should we do about staff air travel emissions?

Through the Polis consultation, 173 participants made more than 300 suggestions in their own words and voted over 22,000 times on each others’ comments.

In this way, we crowdsourced a detailed picture of collective opinion. The Polis automated analysis tools displayed patterns of opinion to participants in real-time and then we did extra analysis for deeper understanding.

It was a contentious issue. About half the participants were eager for a wide range of measures to dramatically reduce staff flying, while for others the negative impacts of restricting flights were front of mind.

But through the Polis consultation, we found key points of consensus that were very popular across the board. One of these ‘bridging’ ideas was the principle that any policies on this issue should not exacerbate inequities.

Next, we partnered with a council in Melbourne’s southeast to run a consultation on the issue of extreme heat.

This surfaced many ideas from community members—like reducing or banning artificial grass—that were broadly supported by participants. Views were mixed on many other comments, like a suggestion that new builds on private properties “should be required to keep all existing trees.”

Interestingly, the issue of heat was also discussed in parallel on Facebook, where the council had shared a notice about the consultation.

Comments on the Facebook post often had a combative tone or rejected extreme heat as an issue worth discussing—much more so than in the Polis consultation itself.

There is plenty to unpack here, but this general lesson is clear: different online platforms can foster very different political discussions.

The Polis platform is far from perfect and our research explores the limitations and drawbacks in these case studies, as well as learning from what went well.

There is no silver bullet that can solve these huge societal challenges around democracy and climate change.

Instead, these initiatives add to a growing ecosystem of democratic innovations—from using new digital AI tools to in-person deliberative democracy through climate assemblies—which are being thoughtfully explored and combined around the world.

In this way, we can expand our collective capacity to navigate difficult issues and collaborate across diversity.

The Extreme Ultraviolet and X-ray Irradiance Sensors (EXIS) onboard NOAA’s GOES-19 satellite, which launched on June 25, 2024, are powered on, performing well, and observing the sun.

EXIS measures light from the sun in extreme ultraviolet and soft X-ray (lower energy) wavelengths and identifies the magnitude and location of solar flares. Solar flares are huge eruptions of energy on the sun and often produce clouds of plasma traveling more than a million miles per hour.

When these plasma clouds reach Earth, they can cause radio communications blackouts, disruptions to electric power grids, errors in GPS navigation, and hazards to satellites and astronauts. Additionally, variations in the solar X-ray and ultraviolet light that is absorbed by Earth’s upper atmosphere can impact radio communications and satellite drag.

The sun has periodic increases in the complexity of its magnetic field on a roughly 11-year basis, usually referred to as the “solar cycle.” This complexity not only increases the brightness of the sun in the extreme ultraviolet and soft X-rays, but it also results in increased frequency and magnitude of solar flares. The sun is currently at or near the peak of the current solar cycle, also called solar maximum.

EXIS has two main sensors, the X-Ray Sensor (XRS), which measures soft X-rays, and the Extreme Ultraviolet Sensors (EUVS), which measure extreme ultraviolet light. On September 14, 2024, within a day of the GOES-19 EXIS opening its door and looking at the sun, an X-class solar flare occurred.

The X stands for “extreme,” the most energetic class of flares, seen in the XRS data in Panel (1) above in units of irradiance [W m^-2]. This particular flare erupted from an active region (AR13825) of the sun that had just rotated into Earth’s view. It was accompanied by a large ejection of plasma, which takes about two to three days to get to Earth. EXIS provides the first notice of a flare occurring on the sun. This flare resulted in aurorae visible as far south as Texas.

EXIS, with its multiple sensors, can observe and quantify the light from solar flares and help determine in real-time whether the flares will affect us on Earth. By looking at many wavelengths, scientists can also observe details of the physics of the flares themselves.

For instance, the September 14 flare didn’t just rise to a sharp peak then decay away in the soft X-rays and EUV. Instead, the brightness at these wavelengths pulsated, peaking multiple times within several minutes [as seen in Panels (2), (4), and (5) in the image above], indicating that the energetics of the flare are complex.

The EXIS data capturing these pulsations help researchers learn more about solar dynamics. The results are published in The Astrophysical Journal Letters.

GOES-19 is currently undergoing post-launch testing and checkout of its instruments and systems. After GOES-19 is assigned the operational role as NOAA’s GOES-East satellite in April 2025, EXIS data will provide NOAA’s Space Weather Prediction Center with early indications of impending space weather storms so forecasters can issue alerts, watches, and warnings.

The theory of indirect reciprocity holds that people who earn a good reputation by helping others are more likely to be rewarded by third parties, but widespread cooperation depends on agreement about reputations.

In most theoretical models examining how reputations impact people’s desire to cooperate with one another, reputations are binary—good or bad—and based on limited information. But there is a lot of information available about people’s behavior in today’s world, especially with social media.

Biology professors Joshua B. Plotkin of the University of Pennsylvania and Corina Tarnita of Princeton University lead teams that have been collaborating on theoretical research about cooperation. Sebastián Michel-Mata, a doctoral student in Tarnita’s lab, came up with the idea of addressing how to judge someone in an information-rich environment.

“The current theory of indirect reciprocity suggests that reputations can only work in a few societies, those with complex norms of judgment and public institutions that can enforce agreement,” Michel-Mata says. But, as an anthropologist, he sees that such societies are the exception and not the rule, and he wondered about the simple idea that reputations are summaries of multiple actions.

“Prior models have typically assumed that a single action determines someone’s reputation, but I think there’s more nuance to how we assign reputations to people. We often look at multiple actions someone has taken and see if they are mostly good actions or bad actions,” says Mari Kawakatsu, a postdoctoral researcher in Plotkin’s lab.

Through mathematical modeling, the research team showed that looking at multiple actions and forgiving some bad actions is a method of judging behavior that is sufficient to sustain cooperation, a method they call “look twice, forgive once.” Their research is published in Nature.

This builds on previous work Plotkin led about indirect reciprocity. For example, he worked with Kawakatsu and postdoctoral researcher Taylor A. Kessinger on a paper calculating how much gossip is necessary to reach sufficient consensus to sustain cooperation.

Plotkin says of the new paper, “Even if different people in a society subscribe to different norms of judgment, ‘look twice, forgive once’ still generates sufficient consensus to promote cooperation.”

He adds that this method maintains cooperation without gossip or public institutions, which confirms the original hypothesis that Michel-Mata, first author on the paper, had that public institutions are not a prerequisite for reputation-based cooperation. It also offers an important alternative when public institutions exist but erosion of trust in institutions inhibits cooperation.

Kessinger says that, as in the paper about gossip, the game-theoretical model here is a one-shot donation game, also known as a simplified prisoner’s dilemma. Each player can choose to help or not help their partner, and players will periodically update their views of each other’s reputations by observing each other’s interactions with other players, to see if the partner cooperates or “defects” with others. More periodically, players update their strategies.

The idea of indirect reciprocity is “not that I’m nice to Mari because she was nice to me; it’s that I’m nice to Mari because she was nice to Josh, and I have a good opinion of Josh,” Kessinger says.

In this study, “the basic idea is that if you observed two interactions of somebody and at least one of them was an action that you would consider good, then you cooperate with that player, but otherwise you defect with them.”

Kawakatsu says all co-authors were surprised that the “look twice, forgive once” strategy couldn’t be displaced by other strategies, such as always cooperating or always defecting, looking at more than two actions from another player, or forgiving a different proportion of “bad actions.”

Tarnita says that, perhaps most surprisingly, looking more than twice didn’t yield an additional benefit. “Information turned out to be a double-edged sword, so that even when information was freely accessible, individuals did not typically evolve to use all of it,” she says.

Michel-Mata notes that the overall simplicity and robustness of their findings indicate that this behavioral strategy might be old in human societies. The authors see potential for anthropologists and behavioral scientists to build on their work.

The Plotkin and Tarnita labs are continuing to collaborate by exploring how people interact in more than one context, such as at work and in their personal lives. “This touches on a range of contemporary social problems,” Kessinger says, “where private misbehavior becomes a matter of public record.”

As a physicist and data scientist with a keen interest in gender inequality, Fariba Karimi was amazed to discover that the gender gap in physics has remained almost unchanged since 1900. As the citation and coauthorship networks in physics expand, women still make up a small proportion—and the gaps between male and female are getting larger in terms of absolute numbers.

“With roughly the same number of men and women in the world, we should expect this gap to close in an equal society. But what we see in reality is a persistent gap in physics over time,” says Karimi, from the Complexity Science Hub.

“This gap was puzzling me. Why is this happening and when will this gap close?,” adds Karimi, also a professor at Graz University of Technology. Together with computer scientist Jun Sun, from the Leibniz Institute for the Social Sciences, Karimi decided to investigate why these inequities persist.

In a paper, titled “Emergence of group size disparity in growing networks with adoption,” published in Communications Physics, Karimi and Sun introduce a model that combines two key mechanisms—generalized preferential attachment and asymmetric mixing—to explain the enduring disparities observed in academic networks.

First, a look at real-world dynamics

Initially, the researchers constructed and examined the growing networks of citation and coauthorship in the American Physical Society (APS) publications. The APS dataset includes more than 668,000 papers published in APS journals between 1893 and 2020 and more than 8,5 million citations.

They observed that the ratios of male- to female-led papers, as well as male to female researchers, remain considerably high for decades, reflecting systematic disparities that can be associated to historical barriers of entry and social preferences.

“I was fascinated to see more and more female physicists, and more female-led papers in the field, which is good because we had a really large disparity before,” says Sun. “On the other hand, the gap in terms of absolute numbers was getting larger.”

Who takes in the newcomer?

Karimi and Sun decided to investigate these empirical findings further to uncover the reasons behind these disparities. “In real systems, it’s not as simple as someone coming and connecting to others in a network. Especially in systems like academia, it is also a matter of who takes in the newcomer and adopts him or her into their personal network. In our new model, we wanted to consider this adoption process,” explains Karimi.

“We combined two existing models into one,” adds Karimi. In the novel model, asymmetric mixing is the fundamental mechanism of adoption, as it reflects homophily, or the tendency that people who are alike act alike, that “birds of a feather naturally flock together.” A generalized preferential attachment growth mechanism is also incorporated into the model, where popular or established members attract more connections.

“We were able to replicate real-world dynamics with our model,” explains Karimi. Their model demonstrated, as the real-world data, the persistence of gender imbalances in citation and coauthorship trends.

“Our model shows that, if we continue collaborating and citing fellow physicists this way, this gap will remain as it is,” says Karimi.

“The novelty here is that we do not assume that the increase in women is an endogenous factor, but rather an emergent property of a time-dependent growing system. This explains why the gap persists,” explains Karimi.

What-if scenarios

“Our model shows that this slow arrival of women in physics is also related to biases that emerge when one decides to collaborate with a new person. Having an understanding of this mechanism allows us to discuss what-if scenarios,” adds the physicist.

“Theoretically, we could adjust the probability of adoption so that the number of women arriving will speed up and compensate, and they will have a similar adoption experience as men,” said Karimi. “If we don’t take these interventions soon, this gap will not close very easily because of this adoption process. It’s not just about having more women, but also about how they are integrating into networks.”

Implications for academia and beyond

While the study focuses on academic networks, its implications extend beyond academia. According to Karimi, the same network dynamics could also apply to various sectors, including corporate boards and managerial hiring practices, where biases and preferences can shape long-term growth and group representation.

Understanding the mechanisms behind these disparities could allow policymakers, organizations, and academic institutions to design interventions that promote more inclusive and equitable environments.

Creating opportunities for junior women and senior men to collaborate more is one way to promote collaboration equity, suggests Karimi.

“In the model, closing the gap is easily achieved by adjusting a couple of parameters. However, in reality such interventions are much more challenging, such as by giving female researchers more opportunities for funding, as well as promotion,” says Sun.

Catalysts play an important role in the manufacture of many products that we encounter in everyday life—for example in cars for exhaust gas purification or in the chemical industry in the production of fertilizers. Catalysts ensure that these reactions take place with low energy consumption and with as few side reactions as possible.

Traditional catalysts are based on rare and hence expensive precious metals such as iridium and rhodium, which also pollute the environment. “In order to make production processes more sustainable, replacing precious metal catalysts with less toxic alternatives such as main group metals is highly desirable,” says Prof. Dr. Robert Kretschmer, Chair of Inorganic Chemistry at Chemnitz University of Technology.

The use of aluminum or gallium as a substitute for precious metals has several advantages. “They are among the most abundant metals in the Earth’s crust, they are inexpensive and non-toxic, and they have unique chemical properties,” says the Chemnitz chemistry professor.

Unfortunately, catalytic concepts developed for precious metals cannot simply be applied to readily available elements. Therefore, the development of new methods that enable the use of, for example, aluminum and gallium as catalysts is a goal of global research.

Chemnitz scientists from the Chair of Inorganic Chemistry have now observed for the first time a reaction of a gallium compound that was previously only known for expensive metals.

“We have produced an unusual compound in which the gallium atom is only bound to a single carbon atom,” explains Kretschmer. Such compounds are very rare and there are only a few research groups in the world that are able to “tame” such molecules in the laboratory.

The findings are published in the journal Nature Synthesis. A Research Briefing describing the work has been published in the same journal issue.

The reactivity of the new compound is particularly spectacular. “While gallium normally strives to increase the number of bonds in a reaction, our team has now succeeded for the first time in a reaction in which the metal only has one bond at the end—but the gallium atom has jumped two carbon atoms further,” says Kretschmer.

These so-called insertion reactions play an important role in a large number of industrial syntheses, and the observation now opens up perspectives for the further development of catalysis.

Replacing some existing vegetable oil crops with camellia plants could boost cooking oil production while reducing greenhouse gas emissions, water use and pesticide use, according to a modelling study.

That is because camellia is a high-yielding shrub that can thrive in places where some other oil crops struggle. The properties of camellia oil, also known as tea seed oil, suggest it could also be one of the healthier oils, but it is currently little-known and hardly used outside China.

Hairy situation

Yes, when someone pulls your hair – if you have enough hair that someone can pull it – it hurts. But the truth of why that is, and some of the how much and some of the how, has only recently become evident, thanks to a team of researchers scattered across several countries. Reader Sarah MacIntyre brought their work to Feedback’s attention.

The researchers are – there’s no better way to say this – painstaking in how they describe their discovery: “Single-unit axonal recordings revealed that a class of cooling-responsive myelinated nociceptors in human skin is selectively tuned to painful hair-pull stimuli.”

They took pains, also, to explain their work in a more human (rather than just technical) manner: “Together, we have demonstrated that hair-pulling evokes a distinct type of pain with conserved behavioral, neural, and molecular features across humans and mice.” And yes, we share this hair-pulling pain-specificity with our distant murine relatives.

Only humans, though, got examined verbally, as well as hair-pullingly. The scientists pulled hairs on the test subjects’ “forearm, hand, and foot regions”, then asked each hairy-armed, hairy-handed or hairy-footed person to indicate, via a questionnaire, whether the sensation was “throbbing”, “shooting”, “stabbing”, “hot-burning”, “aching”, “tender” or whatever. Some test subjects also had some head hairs pulled.

Hurts are not all equal. The study says that the amount of force required to produce a particular level of pain “was many times lower for hair pull compared to pinprick stimulation”.

Honestly?

If you want to know the truth about dishonesty, good luck to you. That seems the underlying message from František Bartoš at the University of Amsterdam.

His study called “The untrustworthy evidence in dishonesty research” looks at lots of evidence. Then it heaves what appears to be a sigh: “In conclusion, caution is advised when relying on or applying the existing literature on dishonesty.”

Recent years have seen a stream of academic papers about how often people lie or cheat and under what kinds of circumstances.

Some of those papers go further, offering certain tricks that can induce people to behave more honestly. One dishonesty-research project asked people to – just before doing a task on which they might feel tempted to cheat – write down the biblical Ten Commandments.

Bartoš tore into the statistics described in 99 published dishonesty-research papers – papers that other researchers have identified as being worth an extra, gimlet-eyed look.

He reports that many of those papers include numbers that are suspiciously low or high, or “contain results that are ‘too-good-to-be-true’”.

Bartoš does note that his own research, of course, could be wrong. And he writes that “there is reasonable hope” that the general situation is improving. Why? Because, recently, more people have been scrutinising the studies they read, rather than just assuming that everything is done both carefully and honestly.

Self-crumbling satellite

Almost no one wants to have a satellite fall from its decayed orbit, plummet down, down, down and bonk them. That’s why a team of researchers has been playing with ways to make a self-crumbling satellite – building it partially of material that will automatically degrade as the thing plunges into the atmosphere, rendering the big solid object into little bits that burn to near-nothingness.

In glorious techno-lingo, the scientists call their approach “the use of thermites to aid spacecraft demise during re-entry”. They reported their progress at a conference in Orlando, Florida, under the heading “Thermite-for-demise (T4D): From material selection to test campaign”.

Some juicy detail: “The charges are expected to ignite spontaneously during the re-entry phase, supplying additional heat to components critical for the on-ground casualty risk.”

Progress in any engineering adventure tends to come in clumps, each with a new little or big puzzle begging to be solved. Most recently, the team managed to “explain the reasons of the unexpected pressure build-up observed during the tests involving a fraction of activated thermite”.

If reliable, the basic satellite-self-destruction-and-scattering technique will give a new, more widely dispersed metaphorical meaning to Henry Wadsworth Longfellow’s poetic words, “I shot an arrow into the air / It fell to earth, I knew not where”.

Dangerous coconuts

Two further additions to Feedback’s collection of research studies with titles that are useful either for starting or stopping conversations.

First up, “Injuries due to falling coconuts” dropped into an issue of The Journal of Trauma in 1984. And then “Colonoscopy in the sitting position: Lessons learned from self-colonoscopy by using a small-caliber, variable-stiffness colonoscope” was inserted into the journal Gastrointestinal Endoscopy in 2006.

If you find an equally striking example, please send it (with citation details) to [email protected].

Marc Abrahams created the Ig Nobel Prize ceremony and co-founded the magazine Annals of Improbable Research. Earlier, he worked on unusual ways to use computers. His website is improbable.com.

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Maths phobia is older than you might think. A hundred years ago, German physicist Felix Auerbach, lamenting the phenomenon and hoping to find ways to address it, wrote a little book called The Fear of Mathematics and How to Overcome It. Maths, he said, has so much to contribute to society that addressing this fear is a challenge of the highest importance.

Auerbach was a fascinating character – a scientist but also a patron of the arts. Edvard Munch painted his portrait and Bauhaus School founder Walter Gropius designed his house. For a mathematician like myself, the pleasure of…