It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Trump’s Denaturalization Rhetoric Violates the Laws and Spirit of America
Stripping citizens of their citizenship in the name of making the electorate more “American” is arguably one of the most un-American acts imaginable.
Hector Barajas shows his US citizen document with Nathan Fletcher and Congressman Mark Takano after a swear-in ceremony at the immigration office in Downtown San Diego, California on Friday, April 13, 2018. (Photo by Sandy Huffaker/AFP via Getty Images)
You might think that when you are a US citizen, you cannot have that status taken away. You would be wrong, it turns out. And behind that fact is a long and often ugly history.
On Sunday, President Donald Trump said that he would “absolutely” denaturalize American citizens if he could. It comes after a wave of harsh rhetoric directed toward immigrants after the tragic shooting of two National Guard members last week.
Yes, the words that the president says have been discounted. But there’s policy behind the rhetorical provocation.
Denaturalization is the process of stripping citizenship from someone who obtained it illegally, such as by not meeting the requirements or by committing fraud or lying during the application process. At first, government interpreted that standard loosely, leading to years of abuse.
As my colleagues Faiza Patel, Margy O’Herron, and Kendall Verhovek explain: More than 22,000 Americans lost their citizenship between 1907 and 1967 based on political affiliations, race, and gender, according to denaturalization scholar Patrick Weil. President Woodrow Wilson’s administration began denaturalizing German- and Asian-born citizens during World War I, along with anarchists and people who spoke out against the war. During World War II, a push for denaturalization of naturalized citizens from Germany, Italy, and Japan intensified. A primary target included members of the pro-Nazi German-American Bund for disloyalty and insufficient attachment to the principles of the Constitution.
After the war, the Second Red Scare took hold of a country fearful of domestic communism amid its emergence abroad. Sen. Joseph McCarthy of Wisconsin led witch hunts, with denaturalization often used as a tool against accused communists or sympathizers. Among those targets was Harry Bridges, an Australian-born, nationally known labor leader accused of being a communist, who faced an ultimately unsuccessful campaign to revoke his citizenship. The Supreme Court ruled in his favor, not once, but twice.
As Weil puts it, a process that was intended to redress fraud and illegality in the naturalization process became used to “expel from the body politic ‘un-American’ citizens.” But even during wartime, the Supreme Court responded, limiting its use.
Throughout the 20th century, the court issued several rulings setting a high bar for denaturalization. In 1943, the court struck down a move to denaturalize Russian-born William Schneiderman over ties to the Communist Party, requiring a “heavy burden” for rescinding citizenship. And in 1946, the court warned against the use of denaturalization as a “ready instrument for political persecutions.” It’s why in recent decades, denaturalization attempts have been appropriately rare... until now.
Over the summer, Trump directed Justice Department lawyers to “maximally pursue denaturalization proceedings.” At the time, a spokesperson said that “denaturalization proceedings will only be pursued as permitted by law and supported by evidence against individuals who illegally procured or misrepresented facts in the naturalization process.” Trump’s parameters seem to be much broader. In his Thanksgiving Truth Social post, he said he would “denaturalize migrants who undermine domestic tranquility.”
Among his targets? Trump has repeatedly suggested that he is open to denaturalizing New York City Mayor-elect Zohran Mamdani and Rep. Ilhan Omar (D-Minn.). When asked about Elon Musk, he told the press, “We’ll have to take a look.” It appears that crime isn’t so much a motivation as disloyalty; the law isn’t so much a motivation as impulse.
But we shouldn’t mistake impulse for foolishness.
It’s all part of a broader effort to target the rights of immigrants and redefine who is an American. That started on Inauguration Day with the effort to eliminate birthright citizenship, a right that is explicitly in the Constitution. And it’s part of efforts to reverse what top administration officials have called a conspiracy to alter the makeup of the electorate. In an interview, the director of US Citizenship and Immigration Services, Joseph Edlow, accused previous administrations of admitting immigrants to “make them all citizens and then spread them out to try to change demographics elsewhere in the country.” And on the campaign trail last year, Trump adviser Stephen Millerdeclared, “America is for Americans and Americans only.”
Stripping citizens of their citizenship in the name of making the electorate more “American” is arguably one of the most un-American acts imaginable. More than a century ago, the Supreme Court held that naturalized citizens are on the same footing as those born in the country, and for decades, the Supreme Court has made clear that stripping citizens of their citizenship due to their views or expressions “would run counter to our traditions.”
We are a nation of immigrants and also a nation of laws. The courts must continue to ensure that those laws protect naturalized citizens from being punished for speaking out.
Michael Waldman Michael Waldman is President of the Brennan Center for Justice at NYU School of Law, a nonpartisan law and policy institute that focuses on improving the systems of democracy and justice. Full Bio >
Beyond biology: Why social context is the key for improving modern medicine
A new series in "The Lancet" led by a UC Berkeley professor equips policymakers and clinicians with a toolkit to break out of silos and make more informed health decisions.
Can doctors in California learn from a patient who was bounced from one specialist to another in Japan? Can clinicians in London take lessons from a patient seeking asylum while suffering a medical emergency at the U.S.-Mexico border? Can doctors treating refugees in Africa inform health policy around the world?
Holmes is Chancellor’s Professor of Environmental Science, Policy and Management at UC Berkeley. A physician and a cultural and medical anthropologist, he studies social hierarchies and global health disparities. He also co-chairs the Berkeley Center for Social Medicine and co-directs the joint medical anthropology Ph.D. program between Berkeley and UCSF.
Like many doctors, he’s spent decades learning from clinical case studies in leading medical journals. These brief digests are written and reviewed through medical frameworks exclusively, and they describe a patient’s predicament alongside a clinician’s assessment, diagnosis and treatment. They’re a fixture in medical journals and a primary way doctors and all health professionals continue learning after their training.
Now a new monthly series in The Lancet led by Holmes is going beyond clinical diagnoses, tapping experts from the social sciences and humanities, as well as community members from around the world.
The resulting cases provide a critical lens into the cultural and social forces that contribute to each patient’s condition — not just the biological factors. Each unpacks a framework or concept in the social sciences and humanities that researchers hope readers will incorporate into their own practice, leadership or policy-making. The team developed this “translational social medicine toolkit” to help health professionals and policymakers address the deep social and structural causes of global health inequities.
“We hope that these cases will help orient health care practice and become a source of solidarity as we organize to confront obstacles to health and well-being for all in an interconnected world,” Holmes wrote in an essay introducing the series.
It launched with the case of a 22-year-old woman in Japan who suffered from a rare genetic disorder. She was denied admission to a special elementary school because officials said her physical and mental impairments were not severe enough. Psychiatrists declined to prescribe her medications because they could aggravate her heart condition. When she went to the hospital during a crisis, she was denied care because the hospital lacked adequate staffing.
In unpacking her case, the research team explained the concept of “medical compartmentalization” — the fragmentation of medical services that harms people whose complex conditions do not fit neatly into simple categories. The physicians and social scientists who wrote the case together said it illustrated clear ways the system can be improved.
“We want a middle-range theory that can be relevant in lots of other clinics, hospitals, policies and countries in the world but also really touches ground with this particular patient or case,” Holmes said. “And then we try to make sure the theory would both show the depth of social theory and be really understandable.”
The latest piece in the series, published Thursday, describes the experience of a 45-year-old asylum seeker suffering from kidney stone complications. A volunteer clinician in Tijuana treated the man before he crossed into the U.S. Once detained in an Immigration and Customs Enforcement facility, the man sought help from a nonprofit that could help advocate for him when he was given inadequate medical treatment. But when the organization requested the man’s medical records, the doctor from Tijuana became concerned about privacy laws and legal liabilities.
The case demonstrates the need for what the researchers term “structural intercompetency,” or the ability of experts to be aware of and address social, political, legal and economic processes and systems affecting a patient’s health that extend beyond health care alone. It showcases the importance of doctors needing to work in new, more collaborative ways, said Carlos Martinez, the case’s lead author and an assistant professor of Latin American and Latino studies at UC Santa Cruz.
“They, of course, cannot be experts in all those systems,” said Martinez, a Berkeley alum who was mentored by Holmes. “What we’re really asking is that clinicians become familiar with the other experts who could help in a given patient’s care.”
The project has been a long time coming. Holmes and his colleagues first envisioned it over 20 years ago, when he was a student interested in bridging the fields of medicine and the social sciences and humanities. They eventually launched a similar series in the New England Journal of Medicine, with cases that were primarily rooted in the U.S.
With the series in The Lancet — one of the world’s most esteemed medical journals — they’re broadening the topics to a global audience.
They solicited hundreds of cases from research institutions, clinics and scholars around the world. Then, the 15-person project team — including MD/Ph.D. student researchers from UC Berkeley and UCSF — sifted through over 400 submitted abstracts and identified those that might have the most relevant applications for social concepts.
Last year, they hosted a three-day mini-conference in Chicago, co-sponsored by Berkeley and co-funded by the National Institutes of Health, and flew people in from around the world. There were doctors, nurses and medical researchers as well as scholars from the social sciences and humanities. Community members from an array of backgrounds contributed too, including a Florida-based human rights organizer and an Indigenous health worker from the Amazon of Brazil. Even doctors who work in the Sahrawi refugee camps in Algeria joined to contribute their perspectives.
“One of the goals of the team was to reach out as far as we could beyond the usual places,” Holmes said. “To support people whose lives, stories, health, health care and concepts could be really important for the world to read but who might not usually have as easy a time publishing in a place like TheLancet.”
The series is expected to run for 12 months, with the possibility of extending. Holmes said it was especially meaningful work to be doing now, given the shifting political landscape in the U.S. and globally.
“How much can one article a month do in the midst of active authoritarian regimes? I’m not sure,” Holmes said. “But we’re all working hard to develop these articles to keep people who care about health thinking critically and aware of what’s going on, to have empathy and solidarity for people who they might otherwise consider quite different than them.”
Journal
The Lancet
Method of Research
Case study
Article Title
Translational social medicine for global health: introducing Cases in Global Social Medicine
SPACE/COSMOS
Close-up images show how stars explode
Using Georgia State’s CHARA Array, scientists from around the world reveal the surprising complexity of stellar explosions.
ATLANTA — Astronomers have captured images of two stellar explosions — known as novae — within days of their eruption and in unprecedented detail. The breakthrough provides direct evidence that these explosions are more complex than previously thought, with multiple outflows of material and, in some cases, dramatic delays in the ejection process.
The international study, published in the journal Nature Astronomy, used a cutting-edge technique called interferometry at the Center for High Angular Resolution Astronomy (CHARA Array) in California. This approach allowed scientists to combine the light from multiple telescopes, achieving the sharp resolution needed to directly image the rapidly evolving explosions.
“The images give us a close-up view of how material is ejected away from the star during the explosion,” said Georgia State’s Gail Schaefer, director of the CHARA Array. “Catching these transient events requires flexibility to adapt our night-time schedule as new targets of opportunity are discovered.”
Novae occur when a dense stellar remnant called a white dwarf undergoes a runaway nuclear reaction after stealing material from a companion star. Until recently, astronomers could only infer the early stages of these eruptions indirectly, because the expanding material appeared as a single, unresolved point of light.
Revealing how the ejecta are expelled and interact is crucial to understanding how shock waves form in novae, which were first discovered by NASA’s Fermi Large Area Telescope (LAT). In its first 15 years, Fermi-LAT detected GeV emission from more than 20 novae, establishing these explosions as galactic gamma-ray emitters and highlighting their potential as multi-messenger sources.
A Tale of Two Novae
The team imaged two very different novae that erupted in 2021. One, Nova V1674 Herculis, was among the fastest on record, brightening and fading in just days. Images revealed two distinct perpendicular outflows of gas — evidence that the explosion was powered by multiple interacting ejections. Remarkably, these newly emerging flows appeared in the images while NASA’s Fermi Gamma-ray Space Telescope also detected high-energy gamma rays, directly tying the shock-powered emission to the colliding outflows.
The second, Nova V1405 Cassiopeiae, evolved much slower. Surprisingly, it held onto its outer layers for more than 50 days before finally ejecting them, providing the first clear evidence of a delayed expulsion. When the material was finally expelled, new shocks were triggered — again producing gamma rays seen by NASA’s Fermi.
“These observations allow us to watch a stellar explosion in real time, something that is very complicated and has long been thought to be extremely challenging,” said Elias Aydi, lead author of the study and a professor of physics and astronomy at Texas Tech University. “Instead of seeing just a simple flash of light, we’re now uncovering the true complexity of how these explosions unfold. It’s like going from a grainy black-and-white photo to high-definition video.”
Revealing Hidden Structures
The ability to resolve such fine detail comes from the use of interferometry, the same technique that made it possible to image the black hole at the center of our galaxy. These sharp images were further complemented by spectra from major observatories such as Gemini, which tracked the evolving fingerprints of the ejected gas. As new features appeared in the spectra, they lined up with the structures revealed in the interferometric images, providing a powerful one-to-one confirmation of how the flows were shaping and colliding.
“This is an extraordinary leap forward,” said John Monnier, a professor of astronomy at the University of Michigan, a co-author of the study and an expert in interferometric imaging. “The fact that we can now watch stars explode and immediately see the structure of the material being blasted into space is remarkable. It opens a new window into some of the most dramatic events in the universe.”
Implications for Stellar Physics
The results not only reveal unexpected complexity in novae but also help explain their powerful shock waves, which are known to produce high-energy radiation such as gamma rays. NASA’s Fermi telescope has been the key instrument in discovering this connection, establishing novae as natural laboratories for studying shock physics and particle acceleration.
“Novae are more than fireworks in our galaxy — they are laboratories for extreme physics,” said Professor Laura Chomiuk, a co-author from Michigan State University and an expert on stellar explosions. “By seeing how and when the material is ejected, we can finally connect the dots between the nuclear reactions on the star’s surface, the geometry of the ejected material and the high-energy radiation we detect from space.”
The findings challenge the long-held view that nova eruptions are single, impulsive events. Instead, they point to a variety of ejection pathways, including multiple outflows and delayed envelope release, reshaping our understanding of these cosmic blasts.
“This is just the beginning,” Aydi said. “With more observations like these, we can finally start answering big questions about how stars live, die and affect their surroundings. Novae, once seen as simple explosions, are turning out to be much richer and more fascinating than we imagined.”For more information about Georgia State University research and its impact, visit research.gsu.edu. For more information about the CHARA Array, visit the CHARA Array website.
The observations of the two novae were obtained as part of the CHARA Array open-access program funded by the National Science Foundation under Grants No. AST-2034336 and AST-2407956. Institutional support for the CHARA Array is provided by Georgia State’s College of Arts & Sciences, Office of the Provost and Office of the Vice President for Research and Economic Development.
Scientists at Georgia State’s CHARA Array captured images of Nova V1674 Herculis — one of the fastest stellar explosions on record. Images of Nova V1674 Herculis obtained 2.2 days (left) and 3.2 days (middle) after the explosion. The images reveal the formation of two distinct, perpendicular outflows of gas, as highlighted by the green arrows. The panel on the right shows an artistic impression of the explosion.
Credit
Courtesy: The CHARA Array
The CHARA Array is located at the Mount Wilson Observatory in the San Gabriel Mountains of southern California. The six telescopes of the CHARA Array are arranged along three arms. The light from each telescope is transported through vacuum pipes to the central beam combining lab.
Credit
Courtesy: Georgia State University/The CHARA Array
The circles mark the domes of the six CHARA Array telescopes at the historic Mount Wilson Observatory
Credit
Courtesy: Georgia State University/The CHARA Array
Multiple outflows and delayed ejections revealed by early imaging of novae
Article Publication Date
5-Dec-2025
A new look at TRAPPIST-1e, an earth-sized, habitable-zone exoplanet
More research is needed before concluding whether recent detections of methane signatures hint at the existence of an atmosphere or could be stellar contamination, a University of Arizona planetary scientist argues.
Located about 39 light-years from Earth, the TRAPPIST system resembles a miniature version of our solar system: The star, an ultracool red dwarf, and all its planets would comfortably fit inside the orbit of planet Mercury.
Credit: NASA, ESA, CSA, STScI, Joseph Olmsted (STScI)
Of the seven Earth-sized worlds orbiting the red dwarf star TRAPPIST-1, one planet in particular has attracted the attention of scientists, because it orbits the star within the "Goldilocks zone" – a distance where water on its surface is theoretically possible – but only if the planet has an atmosphere. And where there is water, there might be life.
Two recently scientificpapers detail initial observations of the TRAPPIST-1 system obtained by a research group using NASA's James Webb Space Telescope, published in the Astrophysical Journal Letters. In these publications, the authors, including Sukrit Ranjan with the University of Arizona's Lunar and Planetary Laboratory, present a careful analysis of the results so far and offer several potential scenarios for what the planet’s atmosphere and surface may be like.
While the reports are intriguing and show progress toward characterizing the nearest potentially earth-like exoplanet, Ranjan urges caution in a third paper, arguing that more rigorous studies are needed to determine whether TRAPPIST-1e has an atmosphere at all and whether preliminary hints of methane detected by James Webb are indeed signs of an atmosphere or have their origin with its host star.
The TRAPPIST system, so named after the survey that discovered it – "Transiting Planets and Planetesimals Small Telescope project" – is located about 39 light-years from Earth. It resembles a miniature version of our solar system: The star and all its planets would comfortably fit inside the orbit of planet Mercury. A "year" for any given TRAPPIST planet lasts mere days by Earth standards.
"The basic thesis for TRAPPIST-1e is this: If it has an atmosphere, it's habitable," said Ranjan, who is an assistant professor at LPL. “But right now, the first-order question must be, 'Does an atmosphere even exist?'"
To answer this question, researchers aimed the space telescope's powerful Near-Infrared Spectrograph, or NIRSpec, instrument at the TRAPPIST system as planet TRAPPIST-1e transited – i.e. passed in front of – its host star. During a transit, starlight filters through the planet’s atmosphere, if there is one, and is partially absorbed, allowing astronomers to deduce what chemicals it may contain. With each additional transit, the atmospheric contents become clearer as more data is collected.
The four transits of TRAPPIST-1e studied by the team revealed hints of methane. However, because TRAPPIST-1e's star is a so-called M dwarf, about one tenth the size of our sun and only slightly larger than Jupiter, its unique properties call for extra caution when interpreting data, Ranjan said.
"While the sun is a bright, yellow dwarf star, TRAPPIST-1 is an ultracool red dwarf, meaning it is significantly smaller, cooler and dimmer than our sun," he explained. "Cool enough, in fact, to allow for gas molecules in its atmosphere. We reported hints of methane, but the question is, 'is the methane attributable to molecules in the atmosphere of the planet or in the host star?'"
To rule on this question, Ranjan and colleagues simulated scenarios in which TRAPPIST-1e might have a methane-rich atmosphere and evaluated the probability for each of them. In the most likely scenario among the ones tested, the planet resembled Saturn's methane-rich moon, Titan. However, the work showed that even that scenario was very unlikely.
"Based on our most recent work, we suggest that the previously reported tentative hint of an atmosphere is more likely to be 'noise' from the host star," Ranjan said. "However, this does not mean that TRAPPIST-1e does not have an atmosphere – we just need more data."
Ranjan pointed out that while James Webb is revolutionizing exoplanet science, the telescope was not originally designed to study small, Earth-like exoplanets.
"It was designed long before we knew such worlds existed, and we are fortunate that it can study them at all," he said. "There’s only a handful of Earth-sized planets in existence for which it could potentially ever measure any kind of detailed atmosphere composition."
New answers could come from NASA's Pandora mission, currently in development and slated for launch in early 2026. Led by Daniel Apai, professor of astronomy and planetary sciences at the U of A's Steward Observatory, Pandora is a small satellite designed to characterize exoplanet atmospheres and their host stars. Pandora will monitor stars with potentially habitable planets before, during and after they transit in front of their host stars.
In addition, researchers hope that an ongoing, larger round of observations and new analytical techniques could finally tip the scale in one way or another. Currently, the collaboration is focusing on a technique known as dual transit: by observing the star when both TRAPPIST-1e, and TRAPPIST-1b, the innermost and airless planet of the system, pass in front of their star at the same time.
"These observations will allow us to separate what the star is doing from what is going on in the planet's atmosphere – should it have one," Ranjan said.
WASHINGTON, D.C. — A U.S. Naval Research Laboratory’s (NRL) space robotics team received the Best Paper Award in Orbital Robotics at the 2025 International Conference on Space Robotics (iSpaRo) in Sendai, Japan, on Dec. 3. The recognition spotlights NRL’s leadership in autonomous space systems and artificial intelligence–enabled operations.
The APIARY experiment validates the use of artificial intelligence to enable robotic systems to learn, adapt, and operate safely in the challenging microgravity environment of space. The work represents a major step forward for future missions involving spacecraft servicing, in-space assembly, autonomous logistics, and orbital-debris mitigation.
The team includes three early career scientists, NRL Space Roboticist Samantha Chapin, Ph.D., NRL Computer Research Scientist Kenneth Stewart, Ph.D., NRL Computer Research Scientist Roxana Leontie, Ph.D, and NRL’s Senior Scientist for Robotics and Autonomous Systems Glen Henshaw, Ph.D.
“This award highlights NRL’s leadership in space autonomy and AI-enabled technologies,” Henshaw said. “APIARY shows how reinforcement learning can move from theory to mission-ready capability: by delivering autonomous systems that are more intelligent, resilient, and adaptable. While demonstrated in space, these advances provide a scalable framework for operations across domains, from terrestrial to maritime environments.”
The iSpaRo conference brings together leaders from government, academia, and industry to advance research in orbital operations, planetary exploration, and autonomous systems. The Best Paper in Orbital Robotics award recognizes exceptional scientific merit and direct applicability to real-world operations.
“We are deeply grateful to the NASA Ames Research Center Astrobee team for their collaboration and technical partnership that made this milestone possible,” Leontie said. “We also thank the iSpaRo organizers for their engagement and support in enabling our participation and recognition at this year’s conference.”
APIARY’s success also highlights the impact of early-career scientists at NRL, reflecting the Laboratory’s investment in cultivating the next generation of leaders in national-security science and engineering.
About the U.S. Naval Research Laboratory
NRL is a scientific and engineering command dedicated to research that drives innovative advances for the U.S. Navy and Marine Corps from the seafloor to space and in the information domain. NRL, located in Washington, D.C. with major field sites in Stennis Space Center, Mississippi; Key West, Florida; Monterey, California, and employs approximately 3,000 civilian scientists, engineers and support personnel.
NRL offers several mechanisms for collaborating with the broader scientific community, within and outside of the Federal government. These include Cooperative Research and Development Agreements (CRADAs), LP-CRADAs, Educational Partnership Agreements, agreements under the authority of 10 USC 4892, licensing agreements, FAR contracts, and other applicable agreements.
For more information, contact NRL Corporate Communications at NRLPAO@us.navy.mil.
###
Decoding dark matter’s imprint on black-hole gravitational waves
A new study by researchers at the University of Amsterdam shows how gravitational waves from black holes can be used to reveal the presence of dark matter and help determine its properties. The key is a new model, based on Einstein’s theory of general relativity, that tracks in detail how a black hole interacts with the surrounding matter.
Researchers Rodrigo Vicente, Theophanes K. Karydas and Gianfranco Bertone from the UvA Institute of Physics (IoP) and the GRAPPA centre of excellence for Gravitation and Astroparticle Physics Amsterdam have published their results in the journal Physical Review Letters. In their paper, they introduce an improved way to model how dark matter around black holes affects the gravitational waves these systems emit.
Extreme mass-ratio inspirals
The work focuses on so-called extreme mass-ratio inspirals, or EMRIs: systems in which a relatively small, compact object - for example a black hole formed in the collapse of a single star - orbits and slowly spirals into a much more massive black hole, typically found at the centre of a galaxy. As it spirals inward, the smaller object emits a long gravitational-wave signal.
Future space missions such as the European Space Agency’s LISA space antenna, planned for launch in 2035, are expected to record these signals for months or even years, tracking hundreds of thousands to millions of orbital cycles. If modelled accurately, these “cosmic fingerprints” can reveal how matter - especially the mysterious dark matter that is thought to make up most of the matter in the Universe - is distributed in the immediate surroundings of massive black holes.
A relativistic point of view
Before missions like LISA begin taking data, it is crucial to predict in detail what kinds of signals we should expect and how to extract as much information as possible from them. Until now, most studies have relied on simplified descriptions of how the environment affects EMRIs. The new paper by the IoP/GRAPPA physicists closes this gap for a broad class of environments. It provides the first fully relativistic framework – meaning that it uses Einstein’s theory of gravity in full, instead of simpler approximations based on Newtonian gravity – to describe how the surroundings of a massive black hole modify an EMRI’s orbit and the resulting gravitational waves.
The study focuses in particular on dense concentrations of dark matter - often called “spikes” or “mounds” - that may form around massive black holes. By embedding their new relativistic description into state-of-the-art waveform models, the authors show how such structures would leave a measurable imprint on the signals recorded by future detectors. This work represents a fundamental step in a long-term programme that aims to use gravitational waves to map the distribution of dark matter in the Universe and shed light on its fundamental nature.
Journal
Physical Review Letters
How sound moves on Mars
Understanding acoustic propagation within the Martian environment helps scientists understand the planet and will inform future missions.
HONOLULU, Dec. 4, 2025 — Acoustic signals have been important markers during NASA’s Mars missions. Measurements of sound can provide information both about Mars itself — such as turbulence in its atmosphere, changes in its temperature, and its surface conditions — and about the movement of the Mars rovers.
Using these sound measurements to the best extent possible requires an accurate understanding of how sound propagates on Mars. Charlie Zheng, a professor of mechanical and aerospace engineering at Utah State University, and his doctoral student Hayden Baird, who is partially sponsored by the Utah Space Grant Consortium Graduate Fellowship, will present their work simulating sound propagation on Mars Thursday, Dec. 4, at 8:25 a.m. HST as part of the Sixth Joint Meeting of the Acoustical Society of America and Acoustical Society of Japan, running Dec. 1-5 in in Honolulu, Hawaii.
“We expect that the study will provide deeper insight into weather and terrain effects on acoustic propagation in environments that are not easily measured,” said Zheng. “The Martian environment is obviously one of them.”
Baird and Zheng’s work uses NASA’s measurements of the atmospheric conditions and terrain on Mars, most of which have been previously modeled at meter-scale resolutions. They also had access to decades of data about the red planet’s atmospheric composition and properties, as well as seismic studies that measure the ground porosity — all factors that play into how sound propagates.
“The setup of the simulation model used in this study relies heavily on previous results from multiple scientific disciplines,” said Baird.
Focusing on the Jezero crater, the 2021 landing and exploration site of NASA’s Perseverance rover and its attached Ingenuity helicopter, the researchers simulated how sound moves through and scatters off the region’s complex terrains, whether it comes from a moving or stationary source. This will help them understand how other atmospheres compare to our own.
The researchers hope their model will help identify signals and patterns that indicate specific Martian atmospheric events. In the longer term, it may even help with sensor designs for future missions to other planets or moons to study atmospheric conditions.
“This study is a beginning to dive into many potential areas of planetary research,” said Zheng.
In the coming weeks, ASA’s Press Room will be updated with newsworthy stories and the press conference schedule at https://acoustics.org/asa-press-room/.
LAY LANGUAGE PAPERS
ASA will also share dozens of lay language papers about topics covered at the conference. Lay language papers are summaries (300-500 words) of presentations written by scientists for a general audience. They will be accompanied by photos, audio, and video. Learn more at https://acoustics.org/lay-language-papers/.
PRESS REGISTRATION
ASA will grant free registration to credentialed and professional freelance journalists. If you are a reporter and would like to attend the meeting and/or press conferences, contact AIP Media Services at media@aip.org. For urgent requests, AIP staff can also help with setting up interviews and obtaining images, sound clips, or background information.
ABOUT THE ACOUSTICAL SOCIETY OF AMERICA
The Acoustical Society of America is the premier international scientific society in acoustics devoted to the science and technology of sound. Its 7,000 members worldwide represent a broad spectrum of the study of acoustics. ASA publications include The Journal of the Acoustical Society of America (the world’s leading journal on acoustics), JASA Express Letters, Proceedings of Meetings on Acoustics, Acoustics Today magazine, books, and standards on acoustics. The society also holds two major scientific meetings each year. See https://acousticalsociety.org/.
ABOUT THE ACOUSTICAL SOCIETY OF JAPAN
ASJ publishes a monthly journal in Japanese, the Journal of the Acoustical Society of Japan, as well as a bimonthly journal in English, Acoustical Science and Technology, which is available online at no cost https://www.jstage.jst.go.jp/browse/ast. These journals include technical papers and review papers. Special issues are occasionally organized and published. The Society also publishes textbooks and reference books to promote acoustics associated with various topics. See https://acoustics.jp/en/.
