The Atlantic Council has published its second annual report: “Mythical Beasts: Diving into the depths of the global spyware market.”

Too much good detail to summarize, but here are two items:

First, the authors found that the number of US-based investors in spyware has notably increased in the past year, when compared with the sample size of the spyware market captured in the first Mythical Beasts project. In the first edition, the United States was the second-largest investor in the spyware market, following Israel. In that edition, twelve investors were observed to be domiciled within the United States—­whereas in this second edition, twenty new US-based investors were observed investing in the spyware industry in 2024. This indicates a significant increase of US-based investments in spyware in 2024, catapulting the United States to being the largest investor in this sample of the spyware market. This is significant in scale, as US-based investment from 2023 to 2024 largely outpaced that of other major investing countries observed in the first dataset, including Italy, Israel, and the United Kingdom. It is also significant in the disparity it points to ­the visible enforcement gap between the flow of US dollars and US policy initiatives. Despite numerous US policy actions, such as the addition of spyware vendors on the ...

It's been a year full of challenges, but also important victories for digital freedoms. From EFF’s new lawsuit against OPM and DOGE, to launching Rayhunter (our new tool to detect cellular spying), to exposing the censorship of abortion-related content on social media, we’ve been busy! But we’re not the only ones leading the charge. 

On September 10 in San Francisco, we presented the annual EFF Awards to three courageous honorees who are pushing back against unlawful surveillance, championing data privacy, and advancing civil liberties online. This year’s awards went to Just Futures Law, Erie Meyer, and the Software Freedom Law Center, India. 

If you missed the celebration in person, you can still watch it live! The full event is posted on YouTube and the Internet Archive, and a transcript of the live captions is also available.  

WATCH NOW

SEE THE EFF AWARDS CEREMONY ON YOUTUBE

Looking Back, Looking Ahead

EFF Executive Director Cindy Cohn opened the evening by reflecting on our victories this past year and reiterated how vital EFF’s mission to protect privacy and free speech is today. She also announced her upcoming departure as Executive Director after a decade in the role (and over 25 years of involvement with EFF!). No need to be too sentimental—Cindy isn’t going far. As we like to say: you can check out at any time, but you never really leave the fight. 

Cindy then welcomed one of EFF’s founders, Mitch Kapor, who joked that he had been “brought out of cold storage” for the occasion. Mitch recalled EFF’s early days, when no one knew exactly how constitutional rights would interact with emerging technologies—but everyone understood the stakes. “We understood that the matter of digital rights were very important,” he reflected. And history has proven them right. 

Honoring Defenders of Digital Freedom

The first award of the night, the EFF Award for Defending Digital Freedoms, went to the Software Freedom Law Center, India (SFLC.IN). Presenting the award, EFF Civil Liberties Director David Greene emphasized the importance of international partners like SFLC.IN, whose local perspectives enrich and strengthen EFF’s own work. 

SFLC.IN is at the forefront of digital rights in India—challenging internet shutdowns, tracking violations of free expression with their Free Speech Tracker, and training lawyers across the country. Accepting the award, SFLC.IN founder Mishi Choudhary reminded us: “These freedoms are not abstract. They are fought for every day by people, by organizations, and by movements.” 

SFLC.IN founder Mishi Choudhary accepts the EFF Award for Defending Digital Freedoms

Next, EFF Staff Attorney Mario Trujillo introduced the winner of the EFF Award for Protecting Americans’ Data, Erie Meyer. Erie has served as CTO of the Federal Trade Commission and Consumer Financial Protection Bureau, and was a founding member of the U.S. Digital Service. Today, she continues to fight for better government technology and safeguards for sensitive data. 

In her remarks, Erie underscored the urgency of protecting personal data at scale: “We need to protect people’s data the same way we protect this country from national security risks. What’s happening right now is like all the data breaches in history rolled into one. ‘Trust me, bro’ is not a way to handle 550 million Americans’ data.” 

Erie Meyer accepts the EFF Award for Protecting Americans’ Data

Finally, EFF General Counsel Jennifer Lynch introduced the EFF Award for Leading Immigration and Surveillance Litigation, presented to Just Futures Law. Co-founder and Executive Director Paromita Shah accepted on behalf of the organization, which works to challenge the ways surveillance disproportionately harms people of color in the U.S. 

“For years, corporations and law enforcement—including ICE—have been testing the legal limits of their tools on communities of color,” Paromita said in her speech. Just Futures Law has fought back, suing the Department of Homeland Security to reveal its use of AI, and defending activists against surveillance technologies like Clearview AI. 

Just Futures Law Executive Director Paromita Shah accepted the EFF Award for Leading Immigration and Surveillance Litigation

Carrying the Work Forward

We’re honored to shine a spotlight on these award winners, who are doing truly fearless and essential work to protect online privacy and free expression. Their courage reminds us that the fight for civil liberties will be won when we work together—across borders, communities, and movements. 

Join the fight and donate today

A heartfelt thank you to all of the EFF members worldwide who make this work possible. Public support is what allows us to push for a better internet. If you’d like to join the fight, consider becoming an EFF member—you’ll receive special gear as our thanks, and you’ll help power the digital freedom movement. 

And finally, special thanks to the sponsor of this year’s EFF Awards: Electric Capital.

  Catch Up From the Event

Reminder that if you missed the event, you can watch the live recording on our YouTube and the Internet Archive. Plus, a special thank you to our photographers, Alex Schoenfeldt and Carolina Kroon. You can see some of our favorite group photos that were taken during the event, and photos of the awardees with their trophies. 

In 2025, six faculty were granted tenure in the MIT School of Humanities, Arts, and Social Sciences.

Sara Brown is an associate professor in the Music and Theater Arts Section. She develops stage designs for theater, opera, and dance by approaching the scenographic space as a catalyst for collective imagination. Her work is rooted in curiosity and interdisciplinary collaboration, and spans virtual environments, immersive performance installations, and evocative stage landscapes. Her recent projects include “Carousel” at the Boston Lyric Opera; the virtual dance performance “The Other Shore” at the Massachusetts Museum of Contemporary Art and Jacob’s Pillow; and “The Lehman Trilogy” at the Huntington Theatre Company. Her upcoming co-directed work, “Circlusion,” takes place within a fully immersive inflatable space and reimagines the female body’s response to power and violence. Her designs have been seen at the BAM Next Wave Festival in New York, the Festival d’Automne in Paris, and the American Repertory Theater in Cambridge.

Naoki Egami is a professor in the Department of Political Science. He is also a faculty affiliate of the MIT Institute for Data, Systems, and Society. Egami specializes in political methodology and develops statistical methods for questions in political science and the social sciences. His current research programs focus on three areas: external validity and generalizability; machine learning and AI for the social sciences; and causal inference with network and spatial data. His work has appeared in various academic journals in political science, statistics, and computer science, such as American Political Science Review, American Journal of Political Science, Journal of the American Statistical Association, Journal of the Royal Statistical Society (Series B), NeurIPS, and Science Advances. Before joining MIT, Egami was an assistant professor at Columbia University. He received a PhD from Princeton University (2020) and a BA from the University of Tokyo (2015).

Rachel Fraser is an associate professor in the Department of Linguistics and Philosophy. Before coming to MIT, Fraser taught at the University of Oxford, where she also completed her graduate work in philosophy. She has interests in epistemology, language, feminism, aesthetics, and political philosophy. At present, her main project is a book manuscript on the epistemology of narrative.

Brian Hedden PhD ’12 is a professor in the Department of Linguistics and Philosophy, with a shared appointment in the MIT Schwarzman College of Computing in the Department of Electrical Engineering and Computer Science. His research focuses on how we ought to form beliefs and make decisions. He works in epistemology, decision theory, and ethics, including ethics of AI. He is the author of “Reasons without Persons: Rationality, Identity, and Time” (Oxford University Press, 2015) and articles on topics including collective action problems, legal standards of proof, algorithmic fairness, and political polarization, among others. Prior to joining MIT, he was a faculty member at the Australian National University and the University of Sydney, and a junior research fellow at Oxford. He received his BA From Princeton University in 2006 and his PhD from MIT in 2012.

Viola Schmitt is an associate professor in the Department of Linguistics and Philosophy. She is a linguist with a special interest in semantics. Much of her work focuses on trying to understand general constraints on human language meaning; that is, the principles regulating which meanings can be expressed by human languages and how languages can package meaning. Variants of this question were also central to grants she received from the Austrian and German research foundations. She earned her PhD in linguistics from the University of Vienna and worked as a postdoc and/or lecturer at the Universities of Vienna, Graz, Göttingen, and at the University of California at Los Angeles. Her most recent position was as a junior professor at Humboldt University in Berlin.

Miguel Zenón is an associate professor in the Music and Theater Arts Section. The Puerto Rican alto saxophonist, composer, band leader, music producer, and educator is a Grammy Award winner, the recipient of a Guggenheim Fellowship, a MacArthur Fellowship, and a Doris Duke Artist Award. He also holds an honorary doctorate degree in the arts from Universidad del Sagrado Corazón. Zenón has released 18 albums as a band leader and collaborated with some of the great musicians and ensembles of his time. As a composer, Zenón has been commissioned by Chamber Music America, Logan Center for The Arts, The Hyde Park Jazz Festival, Miller Theater, The Hewlett Foundation, Peak Performances, and many of his peers. Zenón has given hundreds of lectures and master classes at institutions all over the world, and in 2011 he founded Caravana Cultural — a program that presents jazz concerts free of charge in rural areas of Puerto Rico.

The San Francisco Police Department is the latest California law enforcement agency to get caught sharing automated license plate reader (ALPR) data with out-of-state and federal agencies. EFF and the ACLU of Northern California are calling them out for this direct violation of California law, which has put every driver in the city at risk and is especially dangerous for immigrants, abortion seekers, and other targets of the federal government.

This week, we sent the San Francisco Police Department a demand letter and request for records under the city’s Sunshine Ordinance following the SF Standard’s recent report that SFPD provided non-California agencies direct access to the city’s ALPR database. Reporters uncovered that at least 19 searches run by these agencies were marked as related to U.S. Immigration and Customs Enforcement (“ICE”). The city’s ALPR database was also searched by law enforcement agencies from Georgia and Texas, both states with severe restrictions on reproductive healthcare.

ALPRs are cameras that capture the movements of vehicles and upload the location of the vehicles to a searchable, shareable database. It is a mass surveillance technology that collects data indiscriminately on every vehicle on the road. As of September 2025, SFPD operates 415 ALPR cameras purchased from the company Flock Safety.

Since 2016, sharing ALPR data with out-of-state or federal agencies—for any reason—violates California law (SB 34). If this data is shared for the purpose of assisting with immigration enforcement, agencies violate an additional California law (SB 54).

In total, the SF Standard found that SFPD had allowed out-of-state cops to run 1.6 million searches of their data. “This sharing violated state law, as well as exposed sensitive driver location information to misuse by the federal government and by states that lack California’s robust privacy protections,” the letter explained.

EFF and ACLU are urging SFPD to launch a thorough audit of its ALPR database, institute new protocols for compliance, and assess penalties and sanctions for any employee found to be sharing ALPR information out of state.

“Your office reportedly claims that agencies outside of California are no longer able to access the SFPD ALPR database,” the letter says. “However, your office has not explained how outside agencies obtained access in the first place or how you plan to prevent future violations of SB 34 and 54.”

As we’ve demonstrated over and over again, many California agencies continue to ignore these laws, exposing sensitive location information to misuse and putting entire communities at risk. As federal agencies continue to carry out violent ICE raids, and many states enforce harsh, draconian restrictions on abortion, ALPR technology is already being used to target and surveil immigrants and abortion seekers. California agencies, including SFPD, have an obligation to protect the rights of Californians, even when those rights are not recognized by other states or the federal government.

See the full letter here: https://www.eff.org/files/2025/09/17/aclu_and_eff_letter_to_sfpd_9.16.2025-1.pdf

Cancer cells have one relentless goal: to grow and divide. While most stick together within the original tumor, some rogue cells break away to traverse to distant organs. There, they can lie dormant — undetectable and not dividing — for years, like landmines waiting to go off.

This migration of cancer cells, called metastasis, is especially common in breast cancer. For many patients, the disease can return months — or even decades — after initial treatment, this time in an entirely different organ.

Robert Weinberg, the Daniel K. Ludwig Professor for Cancer Research at MIT and a Whitehead Institute for Biomedical Research founding member, has spent decades unraveling the complex biology of metastasis and pursuing research that could improve survival rates among patients with metastatic breast cancer — or prevent metastasis altogether.

In his latest study, Weinberg, postdoc Jingwei Zhang, and colleagues ask a critical question: What causes these dormant cancer cells to erupt into a frenzy of growth and division? The group’s findings, published Sept. 1 in The Proceedings of the National Academy of Sciences (PNAS), point to a unique culprit.

This awakening of dormant cancer cells, they’ve discovered, isn’t a spontaneous process. Instead, the wake-up call comes from the inflamed tissue surrounding the cells. One trigger for this inflammation is bleomycin, a common chemotherapy drug that can scar and thicken lung tissue.

“The inflammation jolts the dormant cancer cells awake,” Weinberg says. “Once awakened, they start multiplying again, seeding new life-threatening tumors in the body.”

Decoding metastasis

There’s a lot that scientists still don’t know about metastasis, but this much is clear: Cancer cells must undergo a long and arduous journey to achieve it. The first step is to break away from their neighbors within the original tumor.

Normally, cells stick to one another using surface proteins that act as molecular “velcro,” but some cancer cells can acquire genetic changes that disrupt the production of these proteins and make them more mobile and invasive, allowing them to detach from the parent tumor. 

Once detached, they can penetrate blood vessels and lymphatic channels, which act as highways to distant organs.

While most cancer cells die at some point during this journey, a few persist. These cells exit the bloodstream and invade different tissues—lungs, liver, bone, and even the brain — to give birth to new, often more-aggressive tumors.

“Almost 90 percent of cancer-related deaths occur not from the original tumor, but when cancer cells spread to other parts of the body,” says Weinberg. “This is why it’s so important to understand how these ‘sleeping’ cancer cells can wake up and start growing again.”

Setting up shop in new tissue comes with changes in surroundings — the “tumor microenvironment” — to which the cancer cells may not be well-suited. These cells face constant threats, including detection and attack by the immune system. 

To survive, they often enter a protective state of dormancy that puts a pause on growth and division. This dormant state also makes them resistant to conventional cancer treatments, which often target rapidly dividing cells.

To investigate what makes this dormancy reversible months or years down the line, researchers in the Weinberg Lab injected human breast cancer cells into mice. These cancer cells were modified to produce a fluorescent protein, allowing the scientists to track their behavior in the body.

The group then focused on cancer cells that had lodged themselves in the lung tissue. By examining them for specific proteins — Ki67, ITGB4, and p63 — that act as markers of cell activity and state, the researchers were able to confirm that these cells were in a non-dividing, dormant state.

Previous work from the Weinberg Lab had shown that inflammation in organ tissue can provoke dormant breast cancer cells to start growing again. In this study, the team tested bleomycin — a chemotherapy drug known to cause lung inflammation — that can be given to patients after surgery to lower the risk of cancer recurrence.

The researchers found that lung inflammation from bleomycin was sufficient to trigger the growth of large lung cancer colonies in treated mice — and to shift the character of these once-dormant cells to those that are more invasive and mobile.

Zeroing in on the tumor microenvironment, the team identified a type of immune cells, called M2 macrophages, as drivers of this process. These macrophages release molecules called epidermal growth factor receptor (EGFR) ligands, which bind to receptors on the surface of dormant cancer cells. This activates a cascade of signals that provoke dormant cancer cells to start multiplying rapidly. 

But EGFR signaling is only the initial spark that ignites the fire. “We found that once dormant cancer cells are awakened, they retain what we call an ‘awakening memory,’” Zhang says. “They no longer require ongoing inflammatory signals from the microenvironment to stay active [growing and multiplying] — they remember the awakened state.”

While signals related to inflammation are necessary to awaken dormant cancer cells, exactly how much signaling is needed remains unclear. “This aspect of cancer biology is particularly challenging, because multiple signals contribute to the state change in these dormant cells,” Zhang says.

The team has already identified one key player in the awakening process, but understanding the full set of signals and how each contributes is far more complex — a question they are continuing to investigate in their new work. 

Studying these pivotal changes in the lives of cancer cells — such as their transition from dormancy to active growth — will deepen our scientific understanding of metastasis and, as researchers in the Weinberg Lab hope, lead to more effective treatments for patients with metastatic cancers.

Nearly 300 people gathered Tuesday to mark the ceremonial groundbreaking for Biogen’s new state-of-the-art facility in Kendall Square. The project is the first building to be constructed at MIT’s Kendall Common on the former Volpe federal site, and will serve as a consolidated headquarters for the pioneering biotechnology company which has called Cambridge home for more than 40 years.

In marking the start of construction, Massachusetts Governor Maura Healey addressed the enthusiastic crowd, saying, “Massachusetts science saves lives — saves lives here, saves lives around the world. We celebrate that in Biogen today, we celebrate that in Kendall Common, and we celebrate that in this incredible ecosystem that extends all across our great state. Today, Biogen is not just building a new facility, they are building the future of medicine and innovation.”

Emceed by Kirk Taylor, president and CEO of the Massachusetts Life Sciences Center, the event featured a specially created Lego model of the new building and a historic timeline of Biogen’s origin story overlaid on Kendall Square’s transformation. The program’s theme — “Making breakthroughs happen in Kendall Square” — seemed to elicit a palpable sense of pride among the Biogen and MIT employees, business leaders, and public officials in attendance.

MIT President Sally Kornbluth reflected on the vibrancy of the local innovation ecosystem: “I sometimes say that Kendall Square’s motto might as well be ‘talent in proximity.’ By following that essential recipe, Biogen’s latest decision to intensify its presence here promises great things for the whole region.” Kornbluth described Biogen’s move as “a very important signal to the world right now.”

Biogen’s March 2025 announcement that it will centralize operations at 75 Broadway was lauded as a show of strength for the historic company and the life sciences sector. The 580,000-square-foot research and development headquarters, designed by Elkus Manfredi Architects, will optimize Biogen’s scientific discovery and clinical processes. The new facility is scheduled to open in 2028.

CEO Chris Veihbacher shared his thoughts on Biogen’s decision: “I am proud to stand here with so many individuals who have shaped our past and who are dedicated to our future in Kendall Square. … We decided to invest in the next chapter of Kendall Square because of what this community represents: talent, energy, ingenuity, and collaboration.” Biogen was founded in 1978 by Nobel laureates Phillip Sharp (an MIT Institute Professor and professor of biology emeritus) and Wally Gilbert, both of whom were not only present, but received an impromptu standing ovation, led by Viehbacher.

Kendall Common is being developed by MIT’s Investment Management Company (MITIMCo) and will ultimately include four commercial buildings, four residential buildings (including affordable housing), open space, retail, entertainment, and a community center. MITIMCo’s joint venture partner for the Biogen project is BioMed Realty, a Blackstone Real Estate portfolio company.

Senior Vice President Patrick Rowe, who oversees MITIMCo’s real estate group, says, “Biogen is such a critical anchor for the area. I’m excited for the impact that this project will have on Kendall Square, and for the way that the Kendall Common development can help to further advance our innovation ecosystem.”

This is a nice piece of research: “Mind the Gap: Time-of-Check to Time-of-Use Vulnerabilities in LLM-Enabled Agents“.:

Abstract: Large Language Model (LLM)-enabled agents are rapidly emerging across a wide range of applications, but their deployment introduces vulnerabilities with security implications. While prior work has examined prompt-based attacks (e.g., prompt injection) and data-oriented threats (e.g., data exfiltration), time-of-check to time-of-use (TOCTOU) remain largely unexplored in this context. TOCTOU arises when an agent validates external state (e.g., a file or API response) that is later modified before use, enabling practical attacks such as malicious configuration swaps or payload injection. In this work, we present the first study of TOCTOU vulnerabilities in LLM-enabled agents. We introduce TOCTOU-Bench, a benchmark with 66 realistic user tasks designed to evaluate this class of vulnerabilities. As countermeasures, we adapt detection and mitigation techniques from systems security to this setting and propose prompt rewriting, state integrity monitoring, and tool-fusing. Our study highlights challenges unique to agentic workflows, where we achieve up to 25% detection accuracy using automated detection methods, a 3% decrease in vulnerable plan generation, and a 95% reduction in the attack window. When combining all three approaches, we reduce the TOCTOU vulnerabilities from an executed trajectory from 12% to 8%. Our findings open a new research direction at the intersection of AI safety and systems security...

The science panel reaffirmed greenhouse gases as a threat to human health in the face of administration efforts to downplay climate risks.

One senator called for "an unprecedented response" to defend federal action against climate change.

Rep. Jeff Van Drew, a prominent wind critic, says offshore wind developers gambled — and lost — when they chose to invest in the U.S.

Green Oceans says its mission is environmental protection, but the group's critics say it's promoting fossil energy.

“We have no time to waste in getting Revolution Wind back online,” Rhode Island's attorney general said in a statement Wednesday.

The coastal city’s lawsuit was dismissed last month. Charleston won't appeal the decision.

The state energy secretary said "patriotic communities" are supporting President Donald Trump's artificial intelligence agenda by adding clean electricity to the grid.

China’s green-energy supremacy — and the U.S. retreat from clean tech — brings geopolitical ramifications, the former vice president said.

Kapalua Resort has been dealing with drought that's affected the island's 140,000 residents.

As climate change makes the world hotter and triggers more extreme weather, including drought, thirsty expanses of groomed emerald grass are taxing freshwater supplies that are already under stress.

The report found that many companies aren’t putting enough capital toward decarbonization, and some rely too much on unproven technologies.

The last gasp of a primordial black hole may be the source of the highest-energy “ghost particle” detected to date, a new MIT study proposes.

In a paper appearing today in Physical Review Letters, MIT physicists put forth a strong theoretical case that a recently observed, highly energetic neutrino may have been the product of a primordial black hole exploding outside our solar system.

Neutrinos are sometimes referred to as ghost particles, for their invisible yet pervasive nature: They are the most abundant particle type in the universe, yet they leave barely a trace. Scientists recently identified signs of a neutrino with the highest energy ever recorded, but the source of such an unusually powerful particle has yet to be confirmed.

The MIT researchers propose that the mysterious neutrino may have come from the inevitable explosion of a primordial black hole. Primordial black holes (PBHs) are hypothetical black holes that are microscopic versions of the much more massive black holes that lie at the center of most galaxies. PBHs are theorized to have formed in the first moments following the Big Bang. Some scientists believe that primordial black holes could constitute most or all of the dark matter in the universe today.

Like their more massive counterparts, PBHs should leak energy and shrink over their lifetimes, in a process known as Hawking radiation, which was predicted by the physicist Stephen Hawking. The more a black hole radiates, the hotter it gets and the more high-energy particles it releases. This is a runaway process that should produce an incredibly violent explosion of the most energetic particles just before a black hole evaporates away.

The MIT physicists calculate that, if PBHs make up most of the dark matter in the universe, then a small subpopulation of them would be undergoing their final explosions today throughout the Milky Way galaxy. And, there should be a statistically significant possibility that such an explosion could have occurred relatively close to our solar system. The explosion would have released a burst of high-energy particles, including neutrinos, one of which could have had a good chance of hitting a detector on Earth.

If such a scenario had indeed occurred, the recent detection of the highest-energy neutrino would represent the first observation of Hawking radiation, which has long been assumed, but has never been directly observed from any black hole. What’s more, the event might indicate that primordial black holes exist and that they make up most of dark matter — a mysterious substance that comprises 85 percent of the total matter in the universe, the nature of which remains unknown.

“It turns out there’s this scenario where everything seems to line up, and not only can we show that most of the dark matter [in this scenario] is made of primordial black holes, but we can also produce these high-energy neutrinos from a fluke nearby PBH explosion,” says study lead author Alexandra Klipfel, a graduate student in MIT’s Department of Physics. “It’s something we can now try to look for and confirm with various experiments.”

The study’s other co-author is David Kaiser, professor of physics and the Germeshausen Professor of the History of Science at MIT.

High-energy tension

In February, scientists at the Cubic Kilometer Neutrino Telescope, or KM3NeT, reported the detection of the highest-energy neutrino recorded to date. KM3NeT is a large-scale underwater neutrino detector located at the bottom of the Mediterranean Sea, where the environment is meant to mute the effects of any particles other than neutrinos.

The scientists operating the detector picked up signatures of a passing neutrino with an energy of over 100 peta-electron-volts. One peta-electron volt is equivalent to the energy of 1 quadrillion electron volts.

“This is an incredibly high energy, far beyond anything humans are capable of accelerating particles up to,” Klipfel says. “There’s not much consensus on the origin of such high-energy particles.”

Similarly high-energy neutrinos, though not as high as what KM3NeT observed, have been detected by the IceCube Observatory — a neutrino detector embedded deep in the ice at the South Pole. IceCube has detected about half a dozen such neutrinos, whose unusually high energies have also eluded explanation. Whatever their source, the IceCube observations enable scientists to work out a plausible rate at which neutrinos of those energies typically hit Earth. If this rate were correct, however, it would be extremely unlikely to have seen the ultra-high-energy neutrino that KM3NeT recently detected. The two detectors’ discoveries, then, seemed to be what scientists call “in tension.”

Kaiser and Klipfel, who had been working on a separate project involving primordial black holes, wondered: Could a PBH have produced both the KM3NeT neutrino and the handful of IceCube neutrinos, under conditions in which PBHs comprise most of the dark matter in the galaxy? If they could show a chance existed, it would raise an even more exciting possibility — that both observatories observed not only high-energy neutrinos but also the remnants of Hawking radiation.

“Our best chance”

The first step the scientists took in their theoretical analysis was to calculate how many particles would be emitted by an exploding black hole. All black holes should slowly radiate over time. The larger a black hole, the colder it is, and the lower-energy particles it emits as it slowly evaporates. Thus, any particles that are emitted as Hawking radiation from heavy stellar-mass black holes would be near impossible to detect. By the same token, however, much smaller primordial black holes would be very hot and emit high-energy particles in a process that accelerates the closer the black hole gets to disappearing entirely.

“We don’t have any hope of detecting Hawking radiation from astrophysical black holes,” Klipfel says. “So if we ever want to see it, the smallest primordial black holes are our best chance.”

The researchers calculated the number and energies of particles that a black hole should emit, given its temperature and shrinking mass. In its final nanosecond, they estimate that once a black hole is smaller than an atom, it should emit a final burst of particles, including about 1020 neutrinos, or about a sextillion of the particles, with energies of about 100 peta-electron-volts (around the energy that KM3NeT observed).

They used this result to calculate the number of PBH explosions that would have to occur in a galaxy in order to explain the reported IceCube results. They found that, in our region of the Milky Way galaxy, about 1,000 primordial black holes should be exploding per cubic parsec per year. (A parsec is a unit of distance equal to about 3 light years, which is more than 10 trillion kilometers.)

They then calculated the distance at which one such explosion in the Milky Way could have occurred, such that just a handful of the high-energy neutrinos could have reached Earth and produced the recent KM3NeT event. They find that a PBH would have to explode relatively close to our solar system — at a distance about 2,000 times further than the distance between the Earth and our sun.

The particles emitted from such a nearby explosion would radiate in all directions. However, the team found there is a small, 8 percent chance that an explosion can happen close enough to the solar system, once every 14 years, such that enough ultra-high-energy neutrinos hit the Earth.

“An 8 percent chance is not terribly high, but it’s well within the range for which we should take such chances seriously — all the more so because so far, no other explanation has been found that can account for both the unexplained very-high-energy neutrinos and the even more surprising ultra-high-energy neutrino event,” Kaiser says.

The team’s scenario seems to hold up, at least in theory. To confirm their idea will require many more detections of particles, including neutrinos at “insanely high energies.” Then, scientists can build up better statistics regarding such rare events.

“In that case, we could use all of our combined experience and instrumentation, to try to measure still-hypothetical Hawking radiation,” Kaiser says. “That would provide the first-of-its-kind evidence for one of the pillars of our understanding of black holes — and could account for these otherwise anomalous high-energy neutrino events as well. That’s a very exciting prospect!”

In tandem, other efforts to detect nearby PBHs could further bolster the hypothesis that these unusual objects make up most or all of the dark matter.

This work was supported, in part, by the National Science Foundation, MIT’s Center for Theoretical Physics – A Leinweber Institute, and the U.S. Department of Energy.

Nature Climate Change, Published online: 18 September 2025; doi:10.1038/s41558-025-02451-6

Cities will face increasing risk along with intensified climate shocks but can also act as key agents for mitigation and adaptation. We hope to see more research that could lead to enhanced climate action by providing comprehensive, equitable and practical solutions.