AI helps design new materials that work in the real world

Today, anyone with a large enough artificial intelligence model can generate millions of new material designs in minutes. Unfortunately, that hasn’t led to a huge leap in the number of new materials being used to improve the performance of products like computer chips and rockets.

One reason for the translation gap is that current models don’t reliably factor in the chemical stability of the materials they generate, and unstable materials aren’t very useful in the real world. That forces industries to allocate huge computational budgets to screening out all the unstable materials they generate, in some cases leaving behind a tiny fraction of usable options.

Now, MIT researchers have developed a framework that can be applied at the beginning of the materials generation process to vastly improve the stability rate while achieving targeted material properties. It works by ensuring every design satisfies certain key rules of chemistry relating to the electrons around the materials’ atoms before the expensive generation step begins. The researchers call their approach “crystal generator with valence-constrained design, or CrysVCD.

In a paper published today in Nature Computational Science, the researchers show how CrysVCD allowed several commonly used material models to meet those valence shell rules more often, and used it to achieve high lattice-dynamics stability — a stringent stability test — in nearly 70 percent of computational material generations. They also showed the approach could support the creation of materials with specific desired properties, like high thermal conductivity or high dielectric constant, which is important for computer chips and data centers.

A hint of how the researchers envision people using their system is in the name.

“If material-generating models are like DVDs, we are like the DVD player,” says associate professor of nuclear science and engineering Mingda Li. “You can plug this into any kind of model, not only existing diffusion models but also future models, where people can’t generate enough stable materials, and it can improve stability.”

Joining Li on the paper are Mouyang Cheng SM ’26 and Weiliang Luo, MIT doctoral students in materials science and engineering and chemistry, respectively; Hao Tang PhD ’26, a recent graduate in materials science and engineering; Bowen Yu, a senior undergraduate in physics; Yongqiang Cheng, a staff scientist at the Oak Ridge National Laboratory; Weiwei Xie, an associate professor at Michigan State University; Ju Li, MIT’s Carl Richard Soderberg Professor in Power Engineering; and Heather Kulik, MIT’s Lammot du Pont Professor of Chemical Engineering.

More efficient materials

Computational approaches to materials design have been around for decades, but recent advances in artificial intelligence have increased excitement about their potential. Of particular interest are models that can start with a desired material property and work backward to deliver a material that achieves that goal.

Some of those models use an AI technique known as diffusion, which is commonly used to generate images, while others use large language models like the one powering ChatGPT and Claude, but both approaches struggle to ensure their material generations achieve chemical stability or follow fundamental principles about how chemicals interact and behave.

The solution has been to add another layer of computing on top of the generative process to filter out unstable materials.

“It’s becoming easy to generate the material structure,” Cheng says. “But the validation process, especially the part where you test the stability, has a huge computational cost. It’s something like 90 percent of the computational cost for creating usable materials, and it can take weeks or months.”

Big companies with huge computing budgets can afford to run those processes, but many small companies and research labs can’t, potentially limiting innovation in the field.

“In academia, where we have fewer resources, I think we can still achieve strong performance with smarter designs and other approaches,” Kulik explains. “Generating a model and then down-selecting for stability is inefficient. There’s a high computational cost. But if we put a language model in the beginning of the process to constrain the generation, you can significantly enhance the ratio of stable materials generated.”

The new study involved MIT researchers affiliated with the departments of Materials Science and Engineering, Chemistry, Chemical Engineering, Physics, and Nuclear Science and Engineering. Together the researchers combined AI diffusion models with a language model. In the first stage of their process, the language model produces chemically valid formulas. In the second stage, the diffusion model uses that formula to generate the corresponding atomic structure of the crystal material in coordination with the underlying material generation model.

“Diffusion for typical material generation is a slow process — you can think of it like 1,000 steps to create one material,” Luo says.

“In contrast, when our model is used in the beginning, you can think of it like five steps. It allows you to screen out the unstable materials to generate higher quality materials. And it works with any models generating materials,” Tang adds.

The researchers showed their approach created more stable materials an order of magnitude more efficiently than approaches that rely on screening materials after they’re generated. When fine-tuned on stability metrics, their approach produced crystalline materials that achieved 68 percent mechanical stability and 85 percent metastability, which measures if a material stays in a stable state when undisturbed.

The researchers then used their approach to generate material candidates with high thermal conductivity and easy polarization in an electric field.

“These are materials useful for the semiconductor industry and high thermal conductivity materials relevant to data center cooling,” Ju Li says. “In principle, you could also use this to create other properties, but thermal conductivity has become really important for cooling data centers. There’s been a huge increase in energy use in that industry, and 30 percent of that energy goes to cooling. The industry needs materials with high thermal conductivity to more efficiently remove the heat.”

Democratizing material design

The new approach doesn’t work with every kind of material — it works best with solid structures with highly ordered internal arrangements. Still, the approach could be used to generate stable new crystalline materials with a host of important properties.

“We are not just generating stable materials, we’re also prioritizing performance,” Cheng says. “Any time you have two goals, achieving those goals with anything over 50 percent is hard in this field. In the past, people might have a goal for specific properties and not stability, or vice-versa, and get a single-digit percentage of materials that fit their goal.”

Ultimately the approach will enable more researchers to develop novel materials for a range of next-generation applications.

“This will save huge computation costs and time by removing downstream selection requirements,” Li says. “That will help not only large efforts that generate hundreds of millions of materials, but also smaller research groups with targeted applications.”

The work was supported, in part, by the U.S. Department of Energy, a Mathworks Engineering Fellowship, the National Science Foundation, and the U.S. Defense Threat Reduction Agency.

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Retooling to help democracy revive

In the 20th century, the United States built the world’s dominant manufacturing powerhouse. A thriving middle class grew, well into the 1970s. The U.S. was a beacon of democracy, defeating fascism in World War II and beating back communism and other forms of authoritarianism during the Cold War. 

To MIT economist Daron Acemoglu, there is a deep intertwining among these things. Democracy, his work has shown, helps economies grow. As the industrial economy expanded, in Britain, the U.S., and other countries in the 19th and 20th centuries, so did democratic participation, as people tried to stake out new rights, or make real the rights ascribed to them. 

“The industrial age created the tools for shared prosperity around which democracy organized,” says Acemoglu, a Nobel Prize-winning economist and Institute Professor at MIT. 

Today, though, income inequality has grown markedly in the U.S., starting around 1980. The U.S. has deindustrialized to a significant extent, offshoring production and hurting shop-floor workers and their families. As Acemoglu sees it, this economic realignment has had deep civic consequences: A stranded working class has become more alienated from the institutions and ideas traditionally buttressing democracy.

And for those around the world supporting democracy, he says, “You really need to have the working classes in your coalition for it to make any sense.”

Acemoglu explores these topics in a new book, “What Happened to Liberal Democracy? Remaking a Politics of Shared Prosperity,” published by Penguin Random House. In it, he looks broadly at the benefits of democracy, the tensions it faces in everyday life, and democracy’s trajectory in recent decades.

Broadly, Acemoglu favors rebuilding “working-class liberalism,” essentially seeking the largest coalition that favors self-government and the rule of law. “Working-class liberalism has strong communal roots, eschews social engineering, and prioritizes shared prosperity, jobs, and public services,” Acemoglu writes in the book.

After all, Acemoglu believes, democracy is the one form of rule that promotes rights and liberties, and allows the flexibility and “experimentation” we need to address all the challenges a complicated world throws at us.

“Democracy is the only way we can make progress in society,” Acemoglu says. “Trying to impose top-down solutions to all our problems will ultimately not work.” 

Along the narrow corridor

Acemoglu has long studied the relationship between economic growth, rights, and democracy. With economist Simon Johnson of MIT and political scientist James Robinson, now of the University of Chicago, Acemoglu published a landmark series of studies in the early 2000s demonstrating that economic growth is helped by the development of stable democratic institutions, including property rights. For that work, Acemoglu, Johnson, and Robinson later shared the 2024 Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel. 

Acemoglu’s 2012 bestseller “Why Nations Fail”— written before democracy’s current challenges seemed as acute — synthesized his research on these topics. His 2019 book “The Narrow Corridor,” co-authored with Robinson, casts democratic governments as essential to liberty because they protect people simultaneously from overreach by an authoritarian state, on the one hand, and from domination by other groups in society, on the other. 

However, as Acemoglu has consistently emphasized, self-governance is an ongoing effort; this machine does not run on its own. Relatedly, in the new book, Acemoglu critiques some famous attempts to formulate governance as a neat “social contract,” including Jean-Jacques Rousseau’s conception of a “general will” in society. 

Those ideas helped make the case for political rights, but actual governance in a pluralistic society will always be a messy process. 

“You have to allow communities, and societies in aggregate, to build rules around shared values for anything to stick as institutions, norms, or aspirations,” Acemoglu says. “When you go down the social contractarian path, you sometimes fool yourself into thinking there are clear solutions to dilemmas that in reality don’t quite have such obvious ways of being resolved.” 

For instance, Acemoglu notes, democracy itself “is built on tolerance and acceptance of plural perspectives, but how do you deal with people who are intolerant?” In the book, he largely regards interventions to stamp out seemingly intolerant thought as being unwise and politically counterproductive.

“You’re not going to have a clear-cut solution to all cases,” he says.

The economic realignment

Even with leaders backing a pragmatic, flexible approach to self-governance, democracy faces another challenge: supporting the material welfare of citizens. And here, “What Happened to Liberal Democracy?” takes an unflinching look at the postwar economy, finding fault lines that have shaken the political order. 

The roughly three decades after World War II were fantastic for many workers in democracies, and certainly in the U.S., where middle-class incomes grew by 2.5 percent annually into the 1970s. 

There were always going to be forces pushing back on this trend, and U.S. companies started offshoring and outsourcing production work to clamp down on wage growth. But one other technological and economic trend occurred just as the middle classes of the industrial economy were reaching new heights. 

“Then computers happened,” writes Acemoglu in the book — referring to a complex set of economic and civic realignments involving technology-driven shifts in work. 

Over time, computers started replacing significant numbers of clerical office workers, shop-floor industrial workers, and other types of employees who were earning middle-class wages without holding a college degree. In recent decades, middle-class incomes have only grown by about 0.5 percent annually. 

To be sure, computers have produced plenty of benefits, and created many new forms of work. But as research shows, those jobs have tended to go mostly to college-educated employees, creating a significant split in society between well-educated, well-paid, white-collar workers, and less-educated, worse-paid workers in blue-collar and service jobs. That national share of income hauled in by the top 1 percent of earners has basically doubled in this time, from 10 percent to nearly 20 percent.

Crucially, in Acemoglu’s analysis, this material gap between more-educated and less-educated social cohorts has translated to U.S. politics, with political groupings reshuffling along educational lines, and cultural politics following suit. That’s the dynamic the U.S. faces now — even as one also accounts for the effects of social media and other polarizing features of contemporary society. 

“We now live in a less-industrial world, and we also live in an age defined by social media, much greater levels of conflict, more polarization, and now AI, and all of that complicates things,” Acemoglu says. 

Always a work in progress

This precise feature of contemporary society — deindustrialization fueling an earnings gap that has led to more political polarization — is what shapes Acemoglu’s prescription in response, the idea that “working-class liberalism” is needed to strengthen democracy. 

There are many potential ingredients in this formula, from politicians determined to reach across class lines to workers regaining the impetus to organize in their workplaces. 

“Trade union participation itself is a very important form of local governance that’s very difficult or unimaginable in an authoritarian society,” Acemoglu says, even while noting that he has not always agreed with the actions of particular unions in the past. 

Still, Acemoglu adds, “I don’t think the economic aspect is the only one, in that you cannot just gain the trust of workers by ensuring there are wage gains. That is an important step but it is not sufficient.” Voters need asurances that politicians are thinking about them, at least share their concerns, and have a grounding in similar values. More candidates today need to seek a shared language about those things.

That’s not easy in a world characterized, in part, by global migrations, increasingly diverse national populations, and economic flux. But it is possible, Acemoglu thinks. 

“There are deep dilemmas faced by liberal democracy that were sometimes going to come to boiling points, and this becomes more heightened when societies such as the U.S. and some European ones are simultaneously becoming more complex, more globalized, and more hetereogeneous,” Acemoglu says. On the other hand, he adds, “Multiracial tensions, I would say, were much worse for the U.S. in the 1950s and 1960s. We made democracy work then, in the face of much more difficult race problems, so why not today?”

None of this is a straightforward task, of course. “Forging working-class liberalism is a tall order in the best of times and much more challenging in today’s polarized environment,” Acemoglu writes in the new book. Still, he adds, even in frustrating moments, the stakes are too important for people to relent.

“Democracy is a success,” Acemoglu says. “It’s easy to fall into a trap of painting the democratic project as being doomed to failure, and I want to avoid that.” He adds: “It continues to be a work in progress.” 

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Cells use a little-known molecule to protect themselves from iron overload

Iron is essential. Our cells need it to produce energy, carry oxygen throughout the body, and power countless chemical reactions that sustain life. But this metal has a dark side. When too much of it is left free inside cells, it can trigger destructive reactions that break down DNA, proteins, and even cell membranes.

Now, MIT associate professor of biology and Whitehead Institute for Biomedical Research member Ankur Jain; MIT assistant professor of biology and Koch Institute for Integrative Cancer Research member Whitney Henry; and Pushkal Sharma PhD '26 have discovered that cells rely on an unexpected protector against this threat: small molecules called polyamines.

The researchers’ detailed findings, published Aug. 14 in the journal Cell, reveal that polyamines act like storage lockers for iron, safely holding the metal in a non-reactive state until cells need it.

These findings solve a decades-old mystery about why cells maintain such extraordinarily high levels of polyamines and uncover a previously unknown defense mechanism that protects cells from toxic iron overload.

This work could also help scientists develop better cancer treatments, by allowing iron overload to trigger cancer cell death. It could also offer new clues about diseases like early-onset Parkinson’s disease, in which mutations affect polyamine levels within neurons.

The Jain Lab studies RNA, the intermediary between DNA and the tiny molecular machines called proteins that perform most of the essential tasks inside cells. The lab is particularly interested in how RNA folds, misfolds, and sometimes clumps inside cells.

Jain and Sharma first began studying polyamines because these molecules bind to RNA and help shape its structure. However, they suspected that polyamines must be playing other roles inside cells: they’re among the most abundant small molecules within cells, present at levels comparable to ATP, the molecule cells use as their energy currency.

“We’ve known that without polyamines, cells stop growing and dividing,” Jain says. “But their best-known function only requires a small fraction of the polyamine levels cells actually have.”

To uncover polyamines’ hidden function inside cells, the researchers used a large-scale genetic approach that allows them to screen the entire genome at once, rather than testing genes one-by-one, in order to find out which cellular processes are impacted when polyamine levels are changed within cells.

The screen revealed that when cells have reduced levels of polyamines, a protein called GPX4 becomes essential for survival. GPX4 is known to prevent harmful chemical reactions that damage the fatty molecules that make up cell membranes. 

The team also found that cells with lower polyamine levels have higher amounts of another protein that acts as an iron sponge and keeps the metal in a mineralized form. Together, these findings led the researchers to hypothesize that polyamines might be helping keep iron in a safe, non-reactive state within cells.

To test this idea, they developed a new fluorescent sensor that would allow them to measure chemically reactive iron inside living cells. The new sensor causes living cells to glow based on the amount of chemically reactive iron they contain, allowing researchers to track any changes under a microscope in real-time.

The team paired the new iron sensor with another sensor they had previously developed that measures polyamine levels within cells. By employing them simultaneously, they observed a striking pattern: As polyamine levels dropped within cells, the amount of chemically reactive iron went up, offering new evidence that polyamines play a key role in preventing toxic iron build up inside cells.

Beyond answering a fundamental biological question, these findings could have implications for cancer treatment. Cancer cells often rely on high polyamine levels to support their rapid growth and division. However, cancer drugs designed to lower polyamine levels to stop cell division have had limited success.

“We saw that when polyamine levels fall, cells rely on GPX4 to protect themselves from iron toxicity,” says Sharma, who is also the first author of the study. “This could mean that combining drugs that lower polyamine levels with those that block GPX4 might be more effective for killing cancer cells than targeting either pathway alone.”

The discovery may also have implications beyond cancer. Mutations in genes that help move polyamines around cells are linked to a rare form of early-onset Parkinson’s disease, and scientists have long observed unusually high levels of iron in the brains of Parkinson’s patients. 

While it is still unclear whether excess iron directly contributes to neuron death in Parkinson’s, the discovery that polyamines help buffer reactive iron inside cells offers a possible explanation for this link and opens new directions for future investigation.

In addition, the researchers expect the new iron sensor to be a valuable tool for other scientists. By allowing them to track chemically reactive iron inside living cells, it could power new discoveries in aging, cancer, and neurodegeneration.

“There are a lot of promising future directions for this work,” Jain says. “It’s exciting to think about how these tools and findings could help answer further questions about disease pathways and potentially help design better therapies.”

This work is supported by grants from the National Institutes of Health, Bumpus Foundation, and Pew Charitable Trusts. The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.

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A new kind of aircraft departs an MIT classroom and arrives at an Ohio factory

A former MIT class project is becoming an $850 million effort to manufacture a new kind of aircraft in Ohio.

Electra began as an idea for a hybrid plane that could take off from shorter runways than traditional airplanes but have more range and speed than all-electric aircraft. Now, like other great MIT projects, it’s making an impact far beyond campus.

The company’s fixed-wing aircraft is designed to make travel easier, especially for people who don’t live in the immediate vicinity of a major airport. The plane features a smaller, more efficient engine than traditional planes, along with batteries to give it added power during takeoffs and landings.

With a range of around 1,200 miles and a cruising speed of around 200 miles per hour, the plane could improve the travel experience for many kinds of trips while cutting down on fuel use. And, given the much shorter runway needs and quieter operation than traditional planes, the plane can leverage unique access points such as barges, parking lots, and soccer fields to take off and land instead of traditional airports. 

“Helping people travel between 50 and 250 miles is the sweet spot for this technology,” says Electra Director of Technology Development Chris Courtin SM ’19, PhD ’24. “This can be a better option than driving or commercial airlines for many kinds of trips. There’s a lot of people traveling in that range and a huge amount of friction in existing ground and air transport systems. This could be a big benefit to those people.”

Courtin has worked on the hybrid plane concept since its inception, first as part of a class project at MIT, then as a teacher’s assistant, and finally as part of his PhD thesis. The company was founded by another alumnus, John Langford ’79, SM ’83, SM ’85, PhD ’87, and counts two MIT professors — Mark Drela and John Hansman — as its founding technical advisors.

“The company has really benefited from a strong collaboration with MIT,” Courtin says. “One of the compelling things about MIT is it gives people space to marry the theoretical side with the practical side — to actually go build the airplane and see if people will buy it.”

Electra has already built and flown a two-seated version of its plane. Last month, the company announced an $850 million investment to scale production of its nine-passenger aircraft in Springfield and Clark County, Ohio. The investment, which is expected to create 1,975 new jobs, means Electra will be building the next chapter of aviation in the state where engine-powered human flight first began.

From concept to company

The origins of Electra date back to a 2017 project among graduate students in MIT class 16.886 (Air Transportation Systems Architecting). Electric vertical takeoff and landing (eVTOL) aircraft were garnering excitement at the time, and Courtin’s group wanted to compare that approach to alternative designs.

“It was an open-ended, project-based class where you look at developments in aerospace,” Courtin says. “My group realized short takeoff and landing aircraft had a lot of advantages over eVTOL for getting people where they wanted to go. We started exploring using the same technology — lightweight, electric motors suitable for aviation — to make a new aircraft, which we now call the ultra-short takeoff and landing aircraft.”

The idea was to use batteries and small electric motors to shorten the runway and landing space of a fixed-wing aircraft while leveraging blown wind to travel farther distances in the sky than would be possible with electric motors alone.

The concept was developed further in several senior design classes co-taught by Drela and Hansman, while Courtin served as a teacher’s assistant. In the classes, student collaborators built a subscale model of the aircraft to prove it would work, testing it in MIT’s Wright Brothers Wind Tunnel and in flight. Courtin went on to work on parts of the concept for his PhD. 

In 2019, John Langford, who had been running the aircraft company Aurora Flight Sciences, which had recently been acquired by Boeing, got involved. Electra was officially formed that year.

As a first step, Electra’s team built the EL2, a two-seated version of its aircraft. That included designing and testing the hybrid propulsion system. The EL2 completed its first test flights in 2023 and has since completed over 200 flights.

The aircraft has a gas-powered generator located in its nose and two batteries under the floor, both of which feed the propellers during takeoff and landing. When cruising, the aircraft uses the generator, which can also charge the batteries.

“The gas generator is like a traditional turbine engine used in a conventional aircraft, only instead of driving a propeller or fan it drives an electric generator,” Courtin explains. “That feeds power to the eight motors on the wing. It allows you to have a smaller and more efficient engine because you can size it for cruising, not takeoff and landing conditions.”

The eight motors create a blown lift effect that allows the aircraft to take off and land in areas about the length of a soccer field, much shorter than the runways for conventional airplanes.

For travelers, “the big benefit is you can save a lot of time,” Courtin says. “You don’t need to go to an airport, and you don’t have to go to a train station.”

Operators could also maximize existing infrastructure at airports:

“If you’re three hours away from the nearest major airport, there’s a lot of friction in that,” Courtin says. “With Electra, we could fly you to the nearest major airport, and you don’t need to use a runway, so it doesn’t add to congestion at these very low-capacity places.”

Electra’s aircraft are also more affordable than traditional aircraft and far more quiet.

“The large number of propellers means you can make them much quieter than if you only had one or two,” Courtin explains. “That’s important because helicopters are restricted from operating in places they otherwise could because of the noise.”

Scaling up

Construction on Electra’s 96-acre Ohio manufacturing facility will begin next year. The facility’s initial phase will be capable of producing 400 of its nine-seat aircraft each year. The next phase will expand capacity to around 800 aircraft per year.

Electra’s team could see their aircraft shuttling people to major airports for longer trips or ultimately eliminating the need for conventional airports entirely.

“If you don’t have an existing airport, that’s a very difficult thing to build these days,” Courtin says. “But finding a soccer field-sized area is not hard, especially with our noise reductions.”

Electra’s team is also exploring applications around military logistics, cargo transport, and humanitarian missions.

For the passenger aircraft application, Electra’s team believes that as it scales production, it will be able to make the passenger aircraft accessible to a broad swath of travelers.

“If we can keep the fixed-wing design simplicity and make this large enough, then the per-seat cost could get to a range where a lot of people would have access to this,” Courtin says. “It wouldn’t just be a luxury product, so it could help a lot of people.”

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The secret love life of the longfin squid

Squid have occupied New England’s maritime imagination for centuries, from fishermen’s tales of strange tentacled creatures to the widely publicized giant squid reports along North Atlantic coastlines in the 1800s. Today, we turn a curious eye toward the longfin inshore squid (Doryteuthis pealeii) — the “Boston squid” — which has long been an important part of regional commercial fisheries. These squid thrive in the emerald green depths off the coast of Massachusetts, where low visibility is characteristic of the turbid, nutrient-rich waters.

Keith Ellenbogen, MIT Sea Grant resident artist and acclaimed underwater photographer, knows these waters well. On a good day, he might have 20 feet of visibility beneath the surface. But even with the clearest conditions, these swift squid evaded Ellenbogen’s lens for months. 

In 2023, over 2.85 million pounds of longfin squid — likely over 6 million individual squid — were landed commercially in Massachusetts, with a value exceeding $2.82 million. Consistently among the top 10 species landed commercially in Massachusetts, the longfin squid shares the ranks with the iconic American lobster, Atlantic surf clam, and sea scallop, underscoring its enduring significance in the state’s seafood industry. 

In 2024, landings came in under 750,000 pounds, roughly a quarter of the previous year’s catch. Likewise, the spring 2024 trawl survey documented in the Massachusetts Division of Marine Fisheries Annual Report recorded a historic low in longfin squid biomass, following a record high in 2023. 

But this drop, while significant, doesn’t necessarily spell trouble for the species. Longfin squid often show large fluctuations in abundance from year to year. Their short lifespan of about six to nine months, combined with their sensitivity to shifting ocean conditions, makes their population dynamics inherently unpredictable. 

Kimberly Hyde, a biological oceanographer with the National Oceanic and Atmospheric Administration (NOAA)’s Northeast Fisheries Science Center (NEFSC), notes that NEFSC research scientists have expanded squid research over the past few years, including a two-year study on longfin squid to better understand their life history and track their maturity and readiness to spawn. Across the Northeast, scientists are also collaborating with the fishing industry through efforts including the Longfin Squid Biological Sampling Program (SQUIBS), Collaborative SQUid Size Monitoring (SQUISM), and the Squid-Squad, a highly interdisciplinary team of scientists, industry members, and managers with a common goal to improve squid science. Still, much of this cephalopod’s story remains hidden from sight. 

After years of trying to find and photograph a squid spawning aggregation, Ellenbogen chartered a vessel and worked with a network of local fishermen to locate concentrations of squid beneath the surface. In New England’s emerald-green, nutrient-rich coastal waters, visibility was limited, and although he knew he was directly above the spawning grounds, finding a cluster of eggs and squid 30 to 40 feet below the surface was far from easy.

“As I descended through the emerald-green waters of Cape Cod, I couldn’t see anything at first,” Ellenbogen recalls. “I knew I was in the right area, but the seafloor seemed empty. Then I noticed a few faint shadows moving in the distance.” 

As he swam closer, the scene slowly revealed itself. 

“First came the squid, then the egg masses, and then hundreds more animals appearing out of the green water. Suddenly I found myself surrounded by squid flashing colors, courting, competing, and spawning,” Ellenbogen says. “It felt like being in a theater, watching a carefully choreographed performance unfold all around me.”

Dozens of squid hovered intently in a circle with arms and tentacles stretching toward the focus of attention: a large pale cluster of eggs fixed to a bed of slipper shells and fingerlike seaweed. Thousands of gelatinous, translucent egg capsules swayed softly in the current. Male and female pairs broke from the outer circle with ceremonial precision, darting inward to spawn. Their alienlike bodies pulsed and flickered with waves of color, from flares of rust-red, golden yellow, and iridescent pink to flashes of lightning white. Their brief lives had culminated here in this critical moment of coordination to give rise to the next generation. 

Longfin squid live fast and die young, exhibiting incredible exponential growth throughout their lifespan of less than one year. They emerge from egg capsules as planktonic hatchlings — paralarvae — that already look like tiny 1.5 millimeter simplified versions of their adult form. 

Still small but fast-growing, juveniles feast on planktonic prey in coastal, surface waters and move deeper in the water column as they grow larger, settling on a life closer to the seafloor. As natural-born ambush and pursuit predators, they begin hunting small crustaceans and other invertebrates — including other squid — with jet propulsion and 10 grasping arms and tentacles.

Like octopuses, squid have chromatophore organs, pigmented cells controlled by nerves and muscles through their central nervous system. Contraction or dilation of these sacs results in mesmerizing iridescence and color shifts. Their color-changing behavior serves several purposes, including camouflage, courtship, and communication through ancient visual language. And to add an extra layer of curiosity, squid themselves are effectively colorblind. Their eyes are well-adapted to detect contrast, brightness, movement, and even polarization, but not to perceive hues like we do.

According to a report from the NEFSC, longfin squid can reach sexual maturity at a mantle length of just 8 centimeters. Nearing adulthood, they migrate offshore to overwinter in deeper, warmer waters along the continental shelf. At night, they form large schools grouped by body size and move upward in the water column to feed. Growth remains rapid and temperature-dependent, with males growing faster and larger than females.

Longfin squid spawn year-round with seasonal and geographic peaks. In New England waters, spawning has been reported from May to August. Egg clusters, or mops, like the one Ellenbogen photographed, act like a hub. As reported by NOAA Fisheries, female squid lay fertilized egg capsules that contain about 150 to 200 eggs each in clusters attached to the ocean bottom. They return repeatedly to deposit multiple clutches of eggs over several weeks, with a typical female laying a total of 3,000 to 6,000 eggs.

Spawning typically occurs in seasonal pulses tied to water temperature and other conditions, sometimes triggering large spawning aggregations — dense gatherings of squid depositing and fertilizing eggs. Males and females gather in the spawning grounds, and density increases until individuals are constantly interacting.

But reproductive biology and behavior are complicated for longfin squid. The NEFSC report highlights unique behavior: Females can store sperm from spawning events for later use, and eggs in the same capsule from a single female may have multiple males from multiple spawning events. 

Consort males, typically the larger males, pair up with a single female during spawning. They swim closely alongside her, often guarding her with their arms, and use their size to intimidate competition. Sneaker males, smaller unpaired squid, use stealth and speed to sneak into position with paired females. Males deposit bundles of spermatophores into the female’s mantle cavity or in a pouch located near her head. 

The competition is guided by visual and chemical signals, including pheromones indicating reproductive readiness, rapid color and pattern changes, as well as strategic arm postures and whole-body displays. A 1999 paper published by the Marine Biological Laboratory catalogued 34 visual displays involving colors, brightness, spots, stripes, iridescence, and polarization signals, as well as 17 specific positions and movements used by squid on the spawning grounds. 

Squid were seen flashing white as a signal to repel other squid. Squid displaying this component are almost always engaged in mate guarding, egg laying, or competitive confrontations. Like humans, female squid can blush, displaying a dark patch on one side of the mantle. But when a squid blushes, it functions as a repellent to courting males. And as captivating as these colorful displays can be, squid communication largely remains an encrypted secret to even the most curious scientists. 

“Keith’s rare glimpse of squid in their natural environment beautifully bridges art and science, reminding us that we still have much to learn,” says Hyde, who has centered her research at NOAA on marine ecosystems and fisheries. 

For most people, squid are known solely as seafood or as shadowy legends, chameleons of the sea. Yet each spring, beneath the cool waters of Cape Cod, millions of longfin squid gather in this remarkable reproductive event, a reminder of the rich biodiversity and productivity of Massachusetts marine ecosystems. 

MIT Sea Grant works to support sustainable fisheries and to promote environmental education and stewardship of our coastal and ocean resources. As MIT Sea Grant’s resident artist, Keith Ellenbogen is working on a long-term project to document extraordinary species and ocean events that unfold just off our coast, revealing hidden moments that few have the opportunity to witness. The longfin squid is one of our region’s most valuable marine resources, and these images help reveal one of the most extraordinary events unfolding right off our coast.

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Brain circuit keeps tabs on what just happened to aid judgment of what’s happening now

A brain must constantly cope with the highly variable, fast-paced nature of the world when trying to judge what’s going on around it. On one hand, it has to be open to whatever new sensory information may come its way, but on the other hand, just to keep up, it has to try to leverage prior experience to make predictions about what seems to be happening. 

In a new study published in Science, MIT neuroscientists identify a circuit that links a sensory decision-making region with one that advises it on how much sensory information just changed.

“This circuit organizes a comparison between what has just happened versus what is happening now in the sensory world in a manner that can be used to act,” says study senior author Mriganka Sur, Newton Professor in The Picower Institute for Learning and Memory and MIT’s Department of Brain and Cognitive Sciences.

Study lead author Ning Leow Phd ’23, a former graduate student in Sur’s lab who is now a postdoc at A*STAR in Singapore, says the study in mice sheds light on closely analogous circuitry in humans, in which an area of the prefrontal cortex (the anterior cingulate cortex, or ACC) makes sensory decisions. The new study shows it bases those decisions on advice about immediate past history from an area of the thalamus called the pulvinar (though in mice, it’s called the lateral posterior thalamus, or LP).

“The brain does not evaluate each new event from scratch,” Leow says. “The pulvinar has traditionally been studied for its role in attention and filtering visual information, but we found that it was also important for comparing present information with the immediate past and highlighting meaningful changes to influence whether we maintain or update a decision.”

As part of Sur’s long-standing interest in how the brain’s cortex integrates sensory perception and learning to produce behavior, Leow and Sur began comprehensively mapping the copious inputs to the LP-ACC circuit, culminating in a paper in 2022. It was clear from that study how the circuit would seem well-positioned to help focus attention, which is what it was known for at the time.

But in thinking more deeply about what focused attention is for, and about how these well-connected regions seemed to sit at the center of not only attention but also perception and action, Sur and Leow hypothesized that they might also have a hand in guiding decisions based on sensory information. The new study presents multiple lines of evidence that it does.

The findings not only shed light on a fundamental function of the brain, Sur says, but could also be applicable to studies of autism, in which many patients show significant differences in the predictions they make about the sensory world. Often, this manifests as difficulty filtering out stimuli that neurotypical people are able to regard as recurring, and therefore mundane.

Which way?

To conduct the study, the researchers trained lab mice to play a video game in which dots on a screen would drift around, but at least some would move together in the same direction (left or right). In each trial, the mice had to discern that trend. From one trial to the next, then, the sensory cue could vary not only by the direction of movement, but also by how what proportion of dots were participating. For instance, on one trial maybe 64 percent of the dots would move left and on the next trial maybe 16 percent of the dots would move right. In this way, the researchers could measure a whole continuum of differences from one trial to the next. 

Meanwhile, as mice played the game, the scientists used a two-photon microscope to record the activity of the LP-ACC circuit and the response of neurons in the ACC. In some experiments, they used a technique called optogenetics to artificially activate the circuit.

By tracking how mice performed the task trial after trial, the researchers were able to see that the mice indeed factored in not only what they were seeing in the moment, but also what they had just seen previously. For instance, when mice guessed right, they were very likely to repeat their guess if the new cue was very similar to the prior one, and very unlikely to if the cue was very different. But if they guessed wrong, then the opposite was true: They wouldn’t repeat that decision if the cue was similar to the last, but would if it looked very different.

Looking in the brain

Of course, behavioral observations only indicated that the mice indeed compared new cues to prior ones. Determining whether that was indeed because of the LP-ACC circuit required the researchers to use optogenetics to perturb it (by stimulating extra activity in the LP’s inputs into the ACC). For instance, optogenetic perturbation of the circuit in the left brain hemisphere made mice less likely to guess that dots were moving right, and perturbation in the right hemisphere made mice more likely to guess dots were moving to the right. But in both cases, the extent of these deviations from normal behavior was directly proportional to the difference between the current cue and the previous one. In other words, perturbing the circuit disrupted how mice used recent sensory history when evaluating new evidence, Leow says.

“That showed the pathway is causally involved in the comparison process that influences how current evidence is interpreted, rather than merely carrying the information,” Leow says.

Moreover, using the microscope imaging (which visualizes calcium levels in neurons, a close proxy of the electrical activity), the researchers extensively analyzed the activity patterns of the LP input into the ACC and how ACC neurons reacted to that input.

“The main takeaway is that the LP and ACC were performing different jobs,” Leow says. “The pulvinar doesn’t appear to be making the decision itself. Instead, it sends that history-referenced sensory comparison to the frontal cortex. The ACC then transforms that information into the neural activity that predicts the animal’s final choice.”

Essentially, the pulvinar advises the ACC on the degree of change so that the frontal cortex can consider whether it’s time to change a guess. After all, if a mouse is guessing right and little is changing, why not keep on trucking? But if there’s a big change, then it might make sense for the mouse to re-evaluate what it’s thinking.

It turns out, the brain has this dedicated circuit for doing so.

In addition to Leow and Sur, the paper’s other authors are Arundhati Natesan, Alexandria Barlowe, Sofie Ährlund-Richter, Tianyu (Cindy) Luo, and Mehrdad Jazayeri.

The National Institutes of Health, a MURI grant, the Simons Foundation Autism Research Initiative, A*STAR, and the Freedom Together Foundation funded the research.

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Meteorite dust holds records of magnetism that may have helped form the sun

Around 4.6 billion years ago, the solar system was little more than a giant ball of gas and dust. Over the next few million years, this “solar nebula” underwent a huge transformation, flattening into a disk of matter that then condensed to form the central sun and orbiting planets. 

Scientists have assumed that the early solar system was shaped mainly through gravity. But a new study finds that magnetism also likely played a role. 

MIT scientists have discovered records of ancient magnetism in the oldest samples of meteorites known today. The team analyzed microscopic grains embedded in a meteorite that was discovered in Antarctica in 2008. These grains, called calcium-aluminum-rich inclusions, or CAIs, originally formed during the solar system’s first 200,000 years, making the samples the oldest known solar system material.

The findings suggest that a magnetic field existed very early on, during the time of the solar nebula. The researchers estimate that this nebular magnetic field was stronger than Earth’s magnetic field today, and likely played a significant role in pulling together primordial matter to form the early sun.

“This transition, from a spherical cloud to a protoplanetary disk, is one of the most significant events in all of solar system history,” says Benjamin Weiss, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. “It has long been theorized that gravity caused this, but our measurements show magnetism likely played a role.”

Weiss and his colleagues report their discovery in a paper appearing this week in the Proceedings of the National Academy of Sciences. The study’s MIT co-authors are first author Cauê Borlina PhD ’22, Elias Mansbach PhD ’24, and Nilanjan Chatterjee, along with Xue-Ning Bai of Tsinghua University, Po-Yen Tung and Richard Harrison of Cambridge University, François Tissot of Caltech, and Kevin McKeegan of the University of California at Los Angeles.

Spinning grains

Magnetic fields are generated by matter that is electrically charged and moving around. In the very early solar system, the collapsing cloud of gas and dust could have whipped up a plasma of charged particles. As these charges spun through the developing disk, they could have produced and sustained a magnetic field.

If this were the case, Weiss and his colleagues reasoned that such early magnetism would have affected material in the disk. As this material condensed, tiny magnetic minerals would have locked in the strength of the magnetic field, preserving its original intensity over billions of years. If these minerals somehow made it to Earth for scientists to measure, their “remanent magnetization” would be evidence that a magnetic field indeed existed and could have played a role in shaping the solar system. 

In fact, the team has previously discovered evidence of a magnetic field, as early as 2 million years into the solar system’s formation. At that time, scientists believe that the sun was already in place, and that the planets were just starting to come together. Thus, the magnetic field Weiss measured likely played a part in the formation of the early planets.

“Nowadays people don’t debate whether magnetism is present when planets are forming. But the debate is around the very early solar system, before planets are forming, when there’s just a disk,” says Borlina, who led the new study as an MIT graduate student and is now an assistant professor at Purdue University. “That’s where the debate still resides, and that’s where we’re operating now.”

Magnetic records

For their new study, the team investigated whether a magnetic field could have existed even earlier in the solar system, when the sun was first coming together. They analyzed samples of DOM 08006, a meteorite that was discovered in 2008 in Dominion Range, a mountain range located along the East Antarctic Ice Sheet. Since it was first recovered, the meteorite has been studied extensively. 

DOM 08006 is one of the most primitive meteorites discovered, and it contains mineral grains that date back to the earliest stages of solar system development, possibly even before the sun was formed. Surprisingly, the meteorite has managed to keep its original composition and minerals.

“Other meteorites went through many different processes over this 4.5 billion year history,” Weiss says. “They were formed in the solar nebula, then added to bodies with water, then got destroyed, moved to the asteroid belt, and then landed here. But somehow, DOM has experienced less alteration than any other meteorite.”

If the early solar system did harbor a magnetic field, records of that field could still be in place in some of DOM’s ancient mineral grains, including CAIs. 

“We know they are the oldest things we have of the early solar system,” Borlina says. “But CAI’s are very complex and are not all the same, even within a 1-millimeter piece of the meteorite. So we have to carefully identify what types they are.” 

From small samples of the parent meteorite, the team isolated tiny grains and identified a handful of CAIs that contained inherently magnetic minerals such as iron. They then put the grains through a series of tests to measure any magnetism they still carry. 

The team identified traces of a magnetic field in the ancient grains. Based on their measurements, they estimate that a magnetic field, of about 150 to 600 microteslas, existed in the early solar system. This field strength is about three to 12 times greater than the Earth’s magnetic field today. 

“We think these kinds of magnetic fields were helping to move gas from the protoplanetary disk, in toward this central star, the sun,” Borlina says. “Gravity is also playing a role. But we are now showing that, if you want to fully understand how the sun and planets formed, you should include magnetic fields in the ingredients that make them.”

This research was supported, in part, by NASA.

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