NIST: Clocks on Earth are ticking a bit more regularly thanks to NIST-F4, a new atomic clock at the National Institute of Standards and Technology (NIST) campus in Boulder, Colorado. This month, NIST researchers published a journal article establishing NIST-F4 as one of the world's most accurate timekeepers. NIST has also submitted the clock for acceptance as a primary frequency standard by the International Bureau of Weights and Measures (BIPM), the body that oversees the world's time.

NIST-F4 measures an unchanging frequency in the heart of cesium atoms, the internationally agreed-upon basis for defining the second since 1967. The clock is based on a "fountain" design that represents the gold standard of accuracy in timekeeping. NIST-F4 ticks at such a steady rate that if it had started running 100 million years ago, when dinosaurs roamed, it would be off by less than a second today.

By joining a small group of similarly elite time pieces run by just 10 countries around the world, NIST-F4 makes the foundation of global time more stable and secure. At the same time, it is helping to steer the clocks NIST uses to keep official U.S. time. Distributed via radio and the internet, official U.S. time is critical for telecommunications and transportation systems, financial trading platforms, data center operations and more.

Firefly Aerospace's sixth Alpha rocket launch failed on April 29, 2025, after an upper-stage anomaly prevented a Lockheed Martin satellite demo from reaching orbit. Both the stage and payload fell into the Pacific Ocean near Antarctica. Space.com reports: The two-stage, 96.7-foot-tall (29.6 meters) Alpha lifted off from California's Vandenberg Space Force Base this morning (April 29), carrying a technology demonstration for aerospace giant Lockheed Martin toward low Earth orbit (LEO). But the payload never got there. Alpha suffered an anomaly shortly after its two stages separated, which led to the loss of the nozzle extension for the upper stage's single Lightning engine. This significantly reduced the engine's thrust, dooming the mission, Firefly said in an update several hours after launch.

Today's mission, which Firefly called "Message in a Booster," was the first of up to 25 that the company will conduct for Lockheed Martin over the next five years. The flight aimed to send a satellite technology demonstrator to LEO. This demo payload "was specifically built to showcase the company's pathfinding efforts for its LM 400 mid-sized, multi-mission satellite bus, and to demonstrate the space vehicle's operational capabilities on orbit for potential customers," Firefly wrote in a prelaunch mission description. "Initial indications showed Alpha's upper stage reached 320 km [199 miles] in altitude. However, upon further assessment, the team learned the upper stage did not reach orbital velocity, and the stage and payload have now safely impacted the Pacific Ocean in a cleared zone north of Antarctica," an update reads.

"Firefly recognizes the hard work that went into payload development and would like to thank our mission partners at Lockheed Martin for their continued support," it continues. "The team is working closely with our customers and the FAA [Federal Aviation Administration] to conduct an investigation and determine root cause of the anomaly. We will provide more information on our mission page after the investigation is completed."

Kosmos 482, a failed Soviet Venus probe, is expected to make an uncontrolled reentry in mid-May after orbiting Earth for 53 years. Gizmodo reports: The lander module from an old Soviet spacecraft is expected to reenter Earth's atmosphere during the second week of May, according to Marco Langbroek, a satellite tracker based in Leiden, the Netherlands. "As this is a lander that was designed to survive passage through the Venus atmosphere, it is possible that it will survive reentry through the Earth atmosphere intact, and impact intact," Langbroek wrote in a blog update. "The risks involved are not particularly high, but not zero."

Kosmos 482 launched on March 31, 1972 from the Baikonur Cosmodrome spaceport in Kazakhstan. The mission was an attempt by the Soviet space program to reach Venus, but it failed to gain enough velocity to enter a transfer trajectory toward the scorching-hot planet. A malfunction resulted in an engine burn that wasn't sufficient to reach Venus' orbit and left the spacecraft in an elliptical Earth orbit, according to NASA. The spacecraft broke apart into four different pieces, with two of the smaller fragments reentering over Ashburton, New Zealand, two days after launch. Meanwhile, two remaining pieces, believed to be the payload and the detached upper-stage engine unit, entered a higher orbit measuring 130 by 6,089 miles (210 by 9,800 kilometers).

The failed mission consisted of a carrier bus and a lander probe, which together form a spherical pressure vessel weighing more than 1,000 pounds (495 kilograms). Considering its mass, "risks are similar to that of a meteorite impact," Langbroek wrote. As of now, it's hard to determine exactly when the spacecraft will reenter. Langbroek estimates that the reentry will take place on May 10, but a more precise date will get clearer as the reentry date nears.

An anonymous reader quotes a report from The Hill: Daily exposure to certain chemicals used to manufacture household plastics may be connected to more than 356,000 cardiovascular-related deaths in 2018 alone, a new analysis has found. These chemicals, called phthalates, are present in products around the world but have particular popularity in the Middle East, South Asia, East Asia and the Pacific -- regions that collectively bore about 75 percent of the global death total, according to the research, published on Tuesday in the Lancet eBioMedicine.

Phthalates, often used in personal care products, children's toys and food packaging and processing materials, are known to disrupt hormone function and have been linked to birth defects, infertility, learning disabilities and neurological disorders. The NYU Langone Health team focused in the analysis on a kind of phthalate called di-2-ethylhexyl phthalate (DEHP), which is used to make items like food containers and medical equipment softer and more flexible. Scientists have already shown that exposure to DEHP can trigger an overactive immune response in the heart's arteries, which over time can be linked to increased risk of heart attack or stroke.

In the new analysis, the researchers estimated that DEHP exposure played a role in 356,238 global deaths in 2018, or nearly 13.5 percent of heart disease mortality among men and women ages 55 through 64. [...] These findings are in line with the team's previous research, which in 2021 determined that phthalates were connected to more than 50,000 premature deaths each year among older Americans -- most of whom succumbed to heart conditions. But this latest analysis is likely the first global estimate of cardiovascular mortality resulting from exposure to these environmental contaminants [...]. In a separate report from the New York Times, author Nina Agrawal highlights some of the caveats with the data.

First of all, the study relies heavily on statistical modeling and assumptions, drawing from prior research that may include biases and confounding factors like diet or socioeconomic status. It also uses U.S.-based risk estimates that may not generalize globally and focuses only on one type of phthalate (DEHP). Additionally, as Agrawal points out, this is an observational study, showing correlation rather than causation. As such, more direct, long-term research is needed to clarify the true health impact of phthalate exposure.

"A new study found that a gene recently recognized as a biomarker for Alzheimer's disease is actually a cause of it," announced the University of California, San Diego, "due to its previously unknown secondary function."

"Researchers at the University of California San Diego used artificial intelligence to help both unravel this mystery of Alzheimer's disease and discover a potential treatment that obstructs the gene's moonlighting role."

A team led by Sheng Zhong, a professor in the university's bioengineering department, had previously discovered a potential blood biomarker for early detection of Alzheimer's disease (called PHGDH). But now they've discovered a correlation: the more protein and RNA that it produces, the more advanced the disease. And after more research they ended up with "a therapeutic candidate with demonstrated efficacy that has the potential of being further developed into clinical tests..." That correlation has since been verified in multiple cohorts from different medical centers, according to Zhong... [T]he researchers established that PHGDH is indeed a causal gene to spontaneous Alzheimer's disease. In further support of that finding, the researchers determined — with the help of AI — that PHGDH plays a previously undiscovered role: it triggers a pathway that disrupts how cells in the brain turn genes on and off. And such a disturbance can cause issues, like the development of Alzheimer's disease....

With AI, they could visualize the three-dimensional structure of the PHGDH protein. Within that structure, they discovered that the protein has a substructure... Zhong said, "It really demanded modern AI to formulate the three-dimensional structure very precisely to make this discovery." After discovering the substructure, the team then demonstrated that with it, the protein can activate two critical target genes. That throws off the delicate balance, leading to several problems and eventually the early stages of Alzheimer's disease. In other words, PHGDH has a previously unknown role, independent of its enzymatic function, that through a novel pathway leads to spontaneous Alzheimer's disease...

Now that the researchers uncovered the mechanism, they wanted to figure out how to intervene and thus possibly identify a therapeutic candidate, which could help target the disease.... Given that PHGDH is such an important enzyme, there are past studies on its possible inhibitors. One small molecule, known as NCT-503, stood out to the researchers because it is not quite effective at impeding PHGDH's enzymatic activity (the production of serine), which they did not want to change. NCT-503 is also able to penetrate the blood-brain-barrier, which is a desirable characteristic. They turned to AI again for three-dimensional visualization and modeling. They found that NCT-503 can access that DNA-binding substructure of PHGDH, thanks to a binding pocket. With more testing, they saw that NCT-503 does indeed inhibit PHGDH's regulatory role.

When the researchers tested NCT-503 in two mouse models of Alzheimer's disease, they saw that it significantly alleviated Alzheimer's progression. The treated mice demonstrated substantial improvement in their memory and anxiety tests...

The next steps will be to optimize the compound and subject it to FDA IND-enabling studies.


The research team published their results on April 23 in the journal Cell.

A new DARPA project called expMath "aims to jumpstart math innovation with the help of AI," writes The Register. America's "Defense Advanced Research Projects Agency" believes mathematics isn't advancing fast enough, according to their article... So to accelerate — or "exponentiate" — the rate of mathematical research, DARPA this week held a Proposers Day event to engage with the technical community in the hope that attendees will prepare proposals to submit once the actual Broad Agency Announcement solicitation goes out...

[T]he problem is that AI just isn't very smart. It can do high school-level math but not high-level math. [One slide from DARPA program manager Patrick Shafto noted that OpenAI o1 "continues to abjectly fail at basic math despite claims of reasoning capabilities."] Nonetheless, expMath's goal is to make AI models capable of:

- auto decomposition — automatically decompose natural language statements into reusable natural language lemmas (a proven statement used to prove other statements); and
auto(in)formalization — translate the natural language lemma into a formal proof and then translate the proof back to natural language.
"How must faster with technology advance with AI agents solving new mathematical proofs?" asks former DARPA research scientist Robin Rowe (also long-time Slashdot reader robinsrowe): DARPA says that "The goal of Exponentiating Mathematics is to radically accelerate the rate of progress in pure mathematics by developing an AI co-author capable of proposing and proving useful abstractions."
Rowe is cited in the article as the founder/CEO of an AI research institute named "Fountain Adobe". (He tells The Register that "It's an indication of DARPA's concern about how tough this may be that it's a three-year program. That's not normal for DARPA.") Rowe is optimistic. "I think we're going to kill it, honestly. I think it's not going to take three years. But I think it might take three years to do it with LLMs. So then the question becomes, how radical is everybody willing to be?"
"We will robustly engage with the math and AI communities toward fundamentally reshaping the practice of mathematics by mathematicians," explains the project's home page. They've already uploaded an hour-long video of their Proposers Day event.

"It's very unclear that current AI systems can succeed at this task..." program manager Shafto says in a short video introducing the project. But... "There's a lot of enthusiasm in the math community for the possibility of changes in the way mathematics is practiced. It opens up fundamentally new things for mathematicians. But of course, they're not AI researchers. One of the motivations for this program is to bring together two different communities — the people who are working on AI for mathematics, and the people who are doing mathematics — so that we're solving the same problem.

At its core, it's a very hard and rather technical problem. And this is DARPA's bread-and-butter, is to sort of try to change the world. And I think this has the potential to do that.

An anonymous reader shared this report from Reuters: The secretive Russian satellite in space that U.S. officials believe is connected to a nuclear anti-satellite weapon program has appeared to be spinning uncontrollably, suggesting it may no longer be functioning in what could be a setback for Moscow's space weapon efforts, according to U.S. analysts... [The Cosmos 2553 satellite launched in 2022] has had various bouts of what appears to be errant spinning over the past year, according to Doppler radar data from space-tracking firm LeoLabs and optical data from Slingshot Aerospace shared with Reuters.

Believed to be a radar satellite for Russian intelligence as well as a radiation testing platform, the satellite last year became the center of U.S. allegations that Russia for years has been developing a nuclear weapon capable of destroying entire satellite networks, such as SpaceX's vast Starlink internet system that Ukrainian troops have been using. U.S. officials assess Cosmos 2553's purpose, though not itself a weapon, is to aid Russia's development of a nuclear anti-satellite weapon. Russia has denied it is developing such a weapon and says Cosmos 2553 is for research purposes....

"This observation strongly suggests the satellite is no longer operational," the Center for Strategic and International Studies, a Washington-based think tank, said of LeoLabs' analysis in its annual Space Threat Assessment published on Friday.

"Future moon astronauts may find water more accessible than previously thought," writes Space.com, citing a new NASA-led experiment: Because the moon lacks a magnetic field like Earth's, the barren lunar surface is constantly bombarded by energetic particles from the sun... Li Hsia Yeo, a planetary scientist at NASA's Goddard Space Flight Center in Maryland, led a lab experiment observing the effects of simulated solar wind on two samples of loose regolith brought to Earth by the Apollo 17 mission... To mimic conditions on the moon, the researchers built a custom apparatus that included a vacuum chamber, where the samples were placed, and a tiny particle accelerator, which the scientists used to bombard the samples with hydrogen ions for several days.

"The exciting thing here is that with only lunar soil and a basic ingredient from the sun — which is always spitting out hydrogen — there's a possibility of creating water," Yeo said in a statement. "That's incredible to think about." Supporting this idea, observations from previous moon missions have revealed an abundance of hydrogen gas in the moon's tenuous atmosphere. Scientists suspect that solar-wind-driven heating facilitates the combination of hydrogen atoms on the surface into hydrogen gas, which then escapes into space. This process also has a surprising upside, the new study suggests. Leftover oxygen atoms are free to bond with new hydrogen atoms formed by repeated bombardment of the solar wind, prepping the moon for more water formation on a renewable basis.

The findings could help assess how sustainable water on the moon is, as the sought-after resource is crucial for both life support and as propellant for rockets. The team's study was published in March in the journal JGR Planets .
NASA created a fascinating animation showing how water is released from the Moon during meteor showers. (In 2016 scientists discovered that when speck of comet debris vaporize on impact, they create shock waves in the lunar soil which can sometimes breach the dry upper layer, releasing water molecules from the hydrated layer below...)

Initial claims that life-associated gases were detected on exoplanet K2-18b are being challenged, with independent reanalysis by Jake Taylor suggesting the data is too noisy to support such conclusions and that stronger, model-independent evidence is needed. NPR reports: Rather than seeing a bump or a wiggle that indicated a signal, "the data is consistent with a flat line," says Taylor, adding that more observations from the telescope are needed to know what can be reliably said about this planet's atmosphere. "If we want to claim biosignatures, we need to be extremely sure."

What this new work shows is that "the strength of the evidence depends on the nitty gritty details of how we interpret the data, and that doesn't pass the bar for me for a convincing detection," says Laura Kreidberg, an expert on the atmospheres of distant planets at the Max Planck Institute for Astronomy in Germany who didn't work on the original research team or this new analysis.

She explains that astronomers can make a lot of different choices when analyzing data; for example, they can make different assumptions about the physics and chemistry at play. "Ideally, for a robust detection, we want it to be model-independent," she says -- that is, they want the signal to show up even if the underlying assumptions change from one analysis to another. But that wasn't the case here.

Longtime Slashdot reader AmiMoJo shares a report from the BBC: China will let scientists from six countries, including the U.S., examine the rocks it collected from the Moon -- a scientific collaboration that comes as the two countries remain locked in a bitter trade war. Two NASA-funded U.S. institutions have been granted access to the lunar samples collected by the Chang'e-5 mission in 2020, the China National Space Administration (CNSA) said on Thursday. CNSA chief Shan Zhongde said that the samples were "a shared treasure for all humanity," local media reported.

Chinese researchers have not been able to access NASA's Moon samples because of restrictions imposed by U.S. lawmakers on the space agency's collaboration with China. Under the 2011 law, Nasa is banned from collaboration with China or any Chinese-owned companies unless it is specifically authorized by Congress. But John Logsdon, the former director of the Space Policy Institute at George Washington University, told BBC Newshour that the latest exchange of Moon rocks have "very little to do with politics." While there are controls on space technology, the examination of lunar samples had "nothing of military significance," he said. "It's international cooperation in science which is the norm."

An anonymous reader shares a Nature story: The United States is known for the deep polarization between its two major political parties -- the right-wing Republicans and left-wing Democrats. Now an analysis of hundreds of thousands of policy documents reveals striking differences in partisan policymakers' use of the scientific literature, with Democratic-led congressional committees and left-wing think tanks more likely to cite research papers than their right-wing counterparts. The analysis also shows that Democrats and left-leaning think tanks are more likely to cite high-impact research, and that the two political sides rarely cite the same studies or even the same topics.

"There are striking differences in amount, content and character of the science cited by partisan policymakers," says Alexander Furnas, a political scientist at Northwestern University in Evanston, Illinois, and a co-author of the analysis, published in Science on 24 April. The researchers used the government-policy database Overton to assemble around 50,000 policy documents produced by US congressional committees in 1995-2021 and around 200,000 reports from 121 ideologically driven US think tanks over a similar period. These documents contained 424,000 scientific references.

A statistical analysis revealed that congressional reports are now more likely to cite science papers than before. But, in each two-year congressional cycle, documents from committees under Democratic control had a higher probability of citing research papers, and the gap between the two parties has increased. Overall, documents from Democratic-controlled committees were nearly 1.8 times more likely to cite science than were reports from Republican-led ones. The differences were starkest for reports produced by partisan think tanks, which the researchers say are "key resources for partisan policymakers." Left-leaning think tanks were 5 times more likely to cite science than right-leaning ones. And there was little overlap between the science referenced by the two sides: just 5-6% of studies were cited by both groups.

An anonymous reader quotes a report from NPR: Air in the U.S. has gotten cleaner for decades, adding years to people's lives and preventing millions of asthma attacks, but nearly half of Americans still live with unhealthy air pollution, a new report finds. The report comes as the Trump administration is considering rolling back some key air quality regulations. Air quality across the country has improved dramatically since regulations like the Clean Air Act were put in place in the 1970s to govern sources of pollution like coal-fired power plants and emissions from diesel trucks. Despite that progress, the air is still unhealthy and polluted in many parts of the country. In 2023, nearly half of the country's inhabitants -- 156 million people -- lived in places heavy in smog or soot pollution that harms their lungs, hearts, and brains, according to the newest edition of the American Lung Association's State of the Air report.

"Both these types of pollution cause people to die. They shorten life expectancy and drive increases in asthma rates," says Mary Rice, a pulmonologist at Harvard University. Pollution levels vary widely across the country, the report finds, with the worst soot pollution, averaged over the whole year, centered on California cities like Fresno and Bakersfield. Ozone pollution is highest in the Los Angeles region. Phoenix, Arizona, and Dallas, Texas, also rank in the top 10 most smog-heavy cities. Nationwide, people of color are about twice as likely to live somewhere with high soot and ozone pollution as white Americans. "The Clean Air Act is one of the greatest success stories in our country," says Rice. NPR notes that the law requires the EPA to revisit the science every five years, reassessing what health researchers have learned about the risks of breathing in poor air and adjusting the regulations accordingly.

"So the air quality standards have kept pace with the science over time, and levels of fine particulate matter have declined over the last 50-plus years," Rice says. "As a result, life expectancy is longer, and asthma rates have gone down." [...] "We are best equipped to protect our health when we have all the information, like weather and air quality," she says.

An anonymous reader quotes a report from the Washington Post: Oil and gas companies are facing hundreds of lawsuits around the world testing whether they can be held responsible for their role in causing climate change. Now, two scientists say they've built a tool that can calculate how much damage each company's planet-warming pollution has caused -- and how much money they could be forced to pay if they're successfully sued. Collectively, greenhouse emissions from 111 fossil fuel companies caused the world $28 trillion in damage from extreme heat from 1991 to 2020, according to a paper published Wednesday in Nature. The new analysis could fuel an emerging legal fight.The authors, Dartmouth associate professor Justin Mankin and Chris Callahan, a postdoctoral researcher at Stanford University, say their model can determine a specific company's share of responsibility over any time period. [...]

Callahan and Mankin's work combines all of these steps -- estimating a company's historical emissions, figuring out how much those emissions contributed to climate change and calculating how much economic damage climate change has caused -- into one "end-to-end" model that links one polluter's emissions to a dollar amount of economic damage from extreme heat. By their calculation, Saudi Aramco is on the hook for $2.05 trillion in economic losses from extreme heat from 1991 to 2020. Russia's Gazprom is responsible for $2 trillion, Chevron for $1.98 trillion, ExxonMobil for $1.91 trillion and BP for $1.45 trillion. Industry groups and companies tend to object to the methodologies of attribution science. They could seek to contest the assumptions that went into each step of Mankin and Callahan's model.

Indeed, every step in that process introduces some room for error, and stringing together all of those steps compounds the uncertainty in the model, according to Delta Merner, lead scientist at theScience Hub for Climate Litigation, which connects scientists and lawyers bringing climate lawsuits. She also mentioned that the researchers relied on a commonly used but simplified climate model known as the Finite Amplitude Impulse Response (FAIR) model. "It is robust for the purpose of what the study is doing," Merner said, "but these models do make assumptions about climate sensitivity, about carbon cycle behavior, energy balance, and all of the simplifications in there do introduce some uncertainty." The exact dollar figures in the paper aren't intended as gospel. But outside scientists said Mankin and Callahan use well-established, peer-reviewed datasets and climate models for every step in their process, and they are transparent about the uncertainty in the numbers.

To celebrate the Hubble Space Telescope's 35th anniversary in orbit, NASA and ESA released a series of new, out-out-of-this-world images spanning planets, nebulae, and galaxies. From a press release: Hubble today is at the peak of its scientific return thanks to the dedication, perseverance and skills of engineers, scientists and mission operators. Astronaut shuttle crews gallantly chased and rendezvoused with Hubble on five servicing missions from 1993 to 2009. The astronauts, including ESA astronauts on two of the servicing missions, upgraded Hubble's cameras, computers and other support systems.

By extending Hubble's operational life the telescope has made nearly 1.7 million observations, looking at approximately 55,000 astronomical targets. Hubble discoveries have resulted in over 22,000 papers and over 1.3 million citations as of February 2025. All the data collected by Hubble is archived and currently adds up to over 400 terabytes. The demand for observing time remains very high with 6:1 oversubscriptions, making it one of the most in-demand observatories today.

Hubble's long operational life has allowed astronomers to see astronomical changes spanning over three decades: seasonal variability on the planets in our solar system, black hole jets traveling at nearly the speed of light, stellar convulsions, asteroid collisions, expanding supernova bubbles, and much more.

Researchers in Germany successfully demonstrated coherent quantum communications over 254 km of existing commercial telecom fiber, marking the first real-world deployment of such a system without cryogenic cooling. Phys.Org reports: Their system uses a coherence-based twin-field quantum key distribution, which facilitates the distribution of secure information over long distances. The quantum communications network was deployed over three telecommunication data centers in Germany (Frankfurt, Kehl and Kirchfeld), connected by 254 km of commercial optical fiber -- a new record distance for real-world and practical quantum key distribution, according to the authors. This demonstration indicates that advanced quantum communications protocols that exploit the coherence of light can be made to work over existing telecom infrastructure. The research has been published in the journal Nature.

An anonymous reader quotes a report from Business Insider: There is some microplastics in normal, healthy arteries," Dr. Ross Clark, a University of New Mexico medical researcher who led the study, told Business Insider before he presented his findings at the meeting of the American Heart Association in Baltimore on Tuesday. "But the amount that's there when they become diseased -- and become diseased with symptoms -- is really, really different," Clark said. Clark and his team measured microplastics and nanoplastics in the dangerous, fatty plaque that can build up in arteries, block blood flow, and cause strokes or heart attacks. Compared to the walls of healthy plaque-free arteries, plaque buildup had 16 times more plastic -- just in the people who didn't have symptoms. In people who had experienced stroke, mini-stroke, or vision loss, the plaque had 51 times more plastic. [...]

To investigate why, Clark studied samples from 48 people's carotid arteries -- the pair of superhighways in your neck that channel blood to your brain. The difference in plastic quantities surprised him, but his team found another concerning trend, too. Cells in the plaque with lots of plastic showed different gene activity than those with low plastic. In the high-plastic environment, one group of immune cells had switched off a gene that's associated with turning off inflammation. Clark's team also found genetic differences in a group of stem cells thought to help prevent heart attacks and strokes by reducing inflammation and stabilizing plaque. "Could it be that microplastics are somehow altering their gene expression?" Clark said. He added that there's "lots more research needed to fully establish that, but at least it gives us a hint as to where to look."

Ross, who specializes in the genetic mechanisms behind disease, agreed that more research is needed, but added that she thinks "these plastics are doing something with these plaques." Tracking microplastics in the human body is a new scientific endeavor as of the last couple years. It's not perfect. Clark's team heated the plaque samples to more than 1,000 degrees Fahrenheit to vaporize plastic polymers and break them down into smaller organic molecules, which can be identified and measured by their mass and other properties. Unfortunately, the lipids in plaque can break down into chemicals that look very similar to polyethylene, the most common plastic found in everything from plastic bags to car parts. "Because we know about this problem, we've taken a lot of steps to remove those lipids and confirm their removal, so that we're sure we're measuring polyethylene," Clark said. Still, he added, "it's a big limitation, and it should be acknowledged that these types of methodologies are continuously improving." "Almost all of what we know about microplastics in the human body, no matter where you look, can be summed up as: It's there, and we need to study further as to what it's doing, if anything," Clark said.

US scientists are fleeing abroad in record numbers as the Trump administration slashes research funding, according to exclusive data analysis by Nature. Applications from American researchers for international positions surged 32% between January and March 2025 compared to the same period last year, while US-based users browsing overseas jobs jumped 35%.

The exodus accelerated in March as the administration intensified science cuts, with job views spiking 68% year-over-year. Applications to Canadian institutions increased 41%, while interest from Canadians in US positions plummeted 13%. Recent months have seen more than 200 federal HIV/AIDS research grants abruptly terminated, cuts to NIH COVID-19 funding revealed, and a $400 million reduction in research grants at Columbia University. "To see this big drop in views and applications to the US -- and the similar rise in those looking to leave -- is unprecedented," said James Richards, who leads Global Talent Solutions at Springer Nature.

European institutions are capitalizing on the talent migration. Aix-Marseille University launched its "Safe Place for Science" initiative with $17.2 million to sponsor researchers, while Germany's Max Planck Society created a Transatlantic Program offering positions to scientists "no longer able to work in the United States." The trend extends beyond Europe, with US-based views of Chinese science positions increasing 30% in the first quarter of 2025.

NASA's oldest active astronaut, Don Pettit, celebrated his 70th birthday by returning to Earth after a seven-month mission aboard the ISS. The Guardian reports: A Soyuz capsule carrying the American and two Russian cosmonauts landed in Kazakhstan on Sunday, Pettit's birthday. "Today at 0420 Moscow time (0120 GMT), the Soyuz MS-26 landing craft with Alexei Ovchinin, Ivan Vagner and Donald (Don) Pettit aboard landed near the Kazakh town of Zhezkazgan," Russia's space agency Roscosmos said.

Spending 220 days in space, Pettit, Ovchinin and Vagner orbited the Earth 3,520 times and completed a journey of 93.3m miles over the course of their mission. It was the fourth spaceflight for Pettit, who has logged more than 18 months in orbit during his 29-year career. Nasa said in a statement that Pettit was "doing well and in the range of what is expected for him following return to Earth." A recording of the touchdown can be viewed here.

Earlier this year, Pettit managed to take one of the best photos ever captured from space. "When I first saw it, I was dazzled by its beauty," wrote Ars Technica's Eric Berger. "But when I looked further into the image, there were just so many amazing details to be found."

"In this image, one can see the core of the Milky Way galaxy, zodiacal light (sunlight diffused by interplanetary dust), streaks of SpaceX Starlink satellites, individual stars, an edge-on view of the atmosphere that appears in burnt umber due to hydroxide emissions, a near-sunrise just over the horizon, and nighttime cities appearing as streaks."

An anonymous reader quotes a report from MIT Technology Review: Arete Glacier Initiative has raised $5 million to improve forecasts of sea-level rise and explore the possibility of refreezing glaciers in place. Off one atoll, just south of the Maldives' capital, Male, researchers are testing one way to capture sand in strategic locations -- to grow islands, rebuild beaches, and protect coastal communities from sea-level rise. Swim 10 minutes out into the En'boodhoofinolhu Lagoon and you'll find the Ramp Ring, an unusual structure made up of six tough-skinned geotextile bladders. These submerged bags, part of a recent effort called the Growing Islands project, form a pair of parentheses separated by 90meters (around 300 feet). The bags, each about two meters tall, were deployed in December 2024, and by February, underwater images showed that sand had climbed about a meter and a half up the surface of each one, demonstrating how passive structures can quickly replenish beaches and, in time, build a solid foundation for new land. "There's just a ton of sand in there. It's really looking good," says Skylar Tibbits, an architect and founder of the MIT Self-Assembly Lab, which is developing the project in partnership with the Male-based climate tech company Invena.

The Self-Assembly Lab designs material technologies that can be programmed to transform or "self-assemble" in the air or underwater, exploiting natural forces like gravity, wind, waves, and sunlight. Its creations include sheets of wood fiber that form into three-dimensional structures when splashed with water, which the researchers hope could be used for tool-free flat-pack furniture.Growing Islands is their largest-scale undertaking yet. Since 2017, the project has deployed 10 experiments in the Maldives, testing different materials, locations, and strategies, including inflatable structures and mesh nets. The Ramp Ring is many times larger than previous deployments and aims to overcome their biggest limitation.

In the Maldives, the direction of the currents changes with the seasons. Past experiments have been able to capture only one seasonal flow, meaning they lie dormant for months of the year. By contrast, the Ramp Ring is "omnidirectional," capturing sand year-round. "It's basically a big ring, a big loop, and no matter which monsoon season and which wave direction, it accumulates sand in the same area," Tibbits says. The approach points to a more sustainable way to protect the archipelago, whose growing population is supported by an economy that caters to 2 million annual tourists drawn by its white beaches and teeming coral reefs. Most of the country's 187 inhabited islands have already had some form of human intervention to reclaim land or defend against erosion, such as concrete blocks, jetties, and breakwaters.

Major scholarly databases have removed dozens of academic journals after researchers discovered they had been purchased by questionable companies and transformed into predatory publications. A January 2025 study identified 36 legitimate journals acquired by recently formed firms with no publishing experience, who then dramatically increased publication fees and output while lowering quality standards.

According to information scientist Alberto Martin-Martin from the University of Granada, publishers are being offered up to hundreds of thousands of euros per journal title. Once acquired, journals typically introduce or raise article-processing charges while churning out papers often outside the publication's original scope. Scopus has delisted all 36 identified journals, and Web of Science removed 11 of 17 affected titles from its index. "As there has been significant change (different ownership), there is no guarantee that review quality is at the same level as the original journals," an Elsevier spokesperson told Nature.