Saturn’s largest moon, Titan, is a complex environment. It hosts rivers and lakes of liquid methane, fields of icy boulders, extensive sand dunes, and, beneath its frozen crust, a vast subsurface ocean. This unique combination makes Titan one of the most intriguing subjects in astrobiology.

A new study led by ETH Zurich fellow Dr. Antonin Affholder examines whether that subsurface ocean could support life. His findings, discussed in a recent SETI Live with SETI Institute communications specialist Beth Johnson, suggest that if life exists there, it may persist only in extremely small amounts, making detection a formidable challenge.

Learn more: https://www.seti.org/news/life-in-titans-ocean-the-microscopic-possibility-of-biomass-on-saturns-moon/

When cells are injured, they can "vomit" their insides out to help them heal faster, according to a new study. While effective, the process could also be implicated in diseases like cancer.

The discovery was made while scientists were investigating a recently discovered cellular process called paligenosis, where mature cells respond to injury by reverting to a younger-seeming progenitor state, similar to a stem cell.

The researchers found that rather than cleaning house slowly, injured cells could quickly jettison waste in a process the team called "cathartocytosis," which may help them achieve a stem cell-like state sooner.

"After an injury, the cell's job is to repair that injury. But the cell's mature cellular machinery for doing its normal job gets in the way," says first author Jeffrey W. Brown, gastroenterologist at Washington University in St. Louis.

"So, this cellular cleanse is a quick way of getting rid of that machinery so it can rapidly become a small, primitive cell capable of proliferating and repairing the injury. We identified this process in the gastrointestinal tract, but we suspect it is relevant in other tissues as well."

This year's budget expires at the end of this month, and Congress must act before October 1 to avert a government shutdown. If Congress passes a budget before then, it will most likely be in the form of a continuing resolution, an extension of this year's funding levels into the first few weeks or months of fiscal year 2026.

The White House's budget request for fiscal year 2026 calls for a 25 percent cut to NASA's overall budget, and a nearly 50 percent reduction in funding for the agency's Science Mission Directorate. These cuts would cut off money for at least 41 missions, including 19 already in space and many more far along in development.

Normally, a president's budget request isn't the final say on matters. Lawmakers in the House and Senate have written their own budget bills in the last several months. There are differences between each appropriations bill, but they broadly reject most of the Trump administration's proposed cuts.

Still, this hasn't quelled the anxieties of anyone with a professional or layman's interest in space science. The 19 active robotic missions chosen for cancellation are operating beyond their original design lifetime. However, in many cases, they are in pursuit of scientific data that no other mission has a chance of collecting for decades or longer.

A “tragic capitulation”
Some of the mission names are recognizable to anyone with a passing interest in NASA's work. They include the agency's two Orbiting Carbon Observatory missions monitoring data signatures related to climate change, the Chandra X-ray Observatory, which survived a budget scare last year, and two of NASA's three active satellites orbiting Mars.

And there's New Horizons, a spacecraft that made front-page headlines in 2015 when it beamed home the first up-close pictures of Pluto. Another mission on the chopping block is Juno, the world's only spacecraft currently at Jupiter.
Both spacecraft have more to offer, according to the scientists leading the missions.

“New Horizons is perfectly healthy," said Alan Stern, the mission's principal investigator at Southwest Research Institute (SWRI). "Everything on the spacecraft is working. All the spacecraft subsystems are performing perfectly, as close to perfectly as one could ever hope. And all the instruments are, too. The spacecraft has the fuel and power to run into the late 2040s or maybe 2050."

New Horizons is a decade and more than 2.5 billion miles (4.1 billion kilometers) beyond Pluto. The probe flew by a frozen object named Arrokoth on New Year's Day 2019, returning images of the most distant world ever explored by a spacecraft. Since then, the mission has continued its speedy departure from the Solar System and could become the third spacecraft to return data from interstellar space.

In a groundbreaking experiment, engineers at the University of Pennsylvania successfully extended quantum networking beyond the laboratory by transmitting signals over commercial fiber-optic cables using the same Internet Protocol (IP) that drives today’s web. Published in Science, the study demonstrates that delicate quantum signals can travel on the same infrastructure that carries routine online traffic. The tests were carried out on Verizon’s campus fiber-optic network.

At the center of the effort is the Penn team’s compact “Q-chip,” designed to coordinate quantum and classical information while operating in full compatibility with modern internet protocols. This innovation could serve as a foundation for a future “quantum internet,” a network that researchers expect may be as transformative as the emergence of the web itself.

Quantum communication depends on entangled particles, which are so strongly connected that altering one instantly changes the other. Leveraging this phenomenon could allow quantum computers to interconnect and share resources, enabling breakthroughs such as more efficient artificial intelligence and the development of novel drugs and materials beyond the capabilities of current supercomputers.

Dark energy—the term used to describe whatever is causing the universe to expand at an increasing rate—is one of the universe's greatest mysteries. The most widely accepted theory currently suggests that dark energy is constant, and the energy of empty space drives cosmic acceleration.

However, last year, findings from the Dark Energy Survey and Dark Energy Spectroscopic Instrument sparked excitement within the cosmology community by hinting that dark energy may actually be evolving.

"This would be our first indication that dark energy is not the cosmological constant introduced by Einstein over 100 years ago but a new, dynamical phenomenon," said Josh Frieman, University of Chicago Professor Emeritus of Astronomy and Astrophysics.

In a new paper published in Physical Review D, Frieman and Anowar Shajib, a NASA Hubble Fellowship Program Einstein Fellow in Astronomy and Astrophysics at UChicago, combine current data from a multitude of probes and find that dynamical models of evolving dark energy can better explain the data than the cosmological constant. If so, their models find, there may be an undiscovered particle out there which is many orders of magnitude smaller than an electron.

University of Chicago spoke with Shajib and Frieman about the new models described in their paper, the implications of these results, and what's next.

On Sept. 7 2025, the skies darkened as Earth's shadow consumed the moon. Skywatchers in many parts of the world saw the moon turn blood red due to a total lunar eclipse.

For amateur astronomers Michael Jäger and Gerald Rhemann in Namibia, the eclipse was not only a sight to behold, but it also gave them an unprecedented opportunity: the chance to capture the interstellar comet 3I/ATLAS under some of the darkest skies on Earth.

Using the eclipse's natural dimming of the moon, the duo was able to take some deep images of the comet, revealing something surprising: the comet glowed green.

Mummifying the dead is a funerary rite that has been practiced for thousands of years in many locations across the world. A new discovery reveals that we may have been underestimating exactly how widespread the practice has been. Bones that show signs of deliberate mummification have been found across Southeast Asia and southern China, with ages dating back to the pre-Neolithic period up to 12,000 years ago.

That's several thousands of years older than the cultures best known for mummification, the Chinchorro people of Chile, who were mummifying their dead 7,000 years ago, and the ancient Egyptians, who were practicing the craft 5,600 years ago.

The reason we might have missed it? The technique used by the earlier Asian cultures is quite different from the more well-known mummification practices. According to a team led by archaeologist Hsiao-chun Hung of the Australian National University, the individuals in their study were slowly smoked over an open fire for long stretches of time.

Early scientific theories—such as those explaining basic phenomena like gravity, burning, and the movement of molecules in water—centered on presumed inherent properties rather than external factors, thereby misleading famous philosophers and scientists, from Aristotle to Scottish botanist Robert Brown, in their theorizing.

A new study by a team of psychology researchers has now found that this tendency is in fact common in the history of science. Moreover, through a series of experiments and surveys, the paper's authors conclude these misfires were likely driven by cognitive constraints, among scientists and non-scientists alike, that have acted as a bottleneck to discovery and shaped the trajectory of scientific theories over millennia.

The study, which appears in the journal Proceedings of the National Academy of Sciences, was conducted by researchers at the University of Edinburgh and New York University.

"Early scientific theories across multiple fields share a common pattern, in that they focus too much on built‑in features and too little on interactions with surroundings," explains Zachary Horne, a lecturer in psychology at the University of Edinburgh and the paper's lead author. "This bias appears throughout the history of science, and its 'fingerprints' can even be seen among scientists today."

The sun has become increasingly active since 2008, a new NASA study shows. Solar activity is known to fluctuate in cycles of 11 years, but there are longer-term variations that can last decades. Case in point: Since the 1980s, the amount of solar activity had been steadily decreasing all the way up to 2008, when solar activity was the weakest on record. At that point, scientists expected the sun to be entering a period of historically low activity.

But then the sun reversed course and started to become increasingly active, as documented in the study, which appears in The Astrophysical Journal Letters. It's a trend that researchers said could lead to an uptick in space weather events, such as solar storms, flares, and coronal mass ejections.

"All signs were pointing to the sun going into a prolonged phase of low activity," said Jamie Jasinski of NASA's Jet Propulsion Laboratory in Southern California, lead author of the new study. "So it was a surprise to see that trend reversed. The sun is slowly waking up."

The earliest recorded tracking of solar activity began in the early 1600s, when astronomers, including Galileo, counted sunspots and documented their changes.

Different parts of Mars have different advantages and disadvantages when it comes to their available resources, just like Earth. The polar caps are likely the most valuable in terms of their water content, which will be critical to any early stage crewed mission to the Red Planet. But to really unlock the fully potential of Mars, geologists think we’ll need to look to the volcanoes, where there is likely to be easily accessible valuable materials like nickel, titanium, and chromium, that were placed there when the volcanoes were active. Reaching those deposits on the side of some of the largest mountains in the solar system safely is a challenge, and one that is tackled in a new paper by Divij Gupta and Arkajit Aich, where they look at the necessary requirements to set up an effective mining operation on the slopes of Olympus and Elysium Mons.

According to a report released today by CopernicusECMWF, in 2025, the Antarctic ozone hole formed earlier than usual and has already reached about 21 million km² in the first half of September.

If you are curious about the history of the ozone hole and how satellites are helping us track its recovery, here's an interesting video recap:
https://t.co/XxJbcEQs6k

📹CAMS

The new image of M87* just released today comes to life in this stunning animation, revealing its incredible evolution over the years!

Watch closely and see how this mysterious supermassive black hole changes over time.

Credit: EHT Collaboration | Animation: Saurabh (MPIfR)

OpenAI’s latest research paper diagnoses exactly why ChatGPT and other large language models can make things up – known in the world of artificial intelligence as “hallucination”. It also reveals why the problem may be unfixable, at least as far as consumers are concerned.

The paper provides the most rigorous mathematical explanation yet for why these models confidently state falsehoods. It demonstrates that these aren’t just an unfortunate side effect of the way that AIs are currently trained, but are mathematically inevitable.

The issue can partly be explained by mistakes in the underlying data used to train the AIs. But using mathematical analysis of how AI systems learn, the researchers prove that even with perfect training data, the problem still exists.

The way language models respond to queries – by predicting one word at a time in a sentence, based on probabilities – naturally produces errors. The researchers in fact show that the total error rate for generating sentences is at least twice as high as the error rate the same AI would have on a simple yes/no question, because mistakes can accumulate over multiple predictions.

In other words, hallucination rates are fundamentally bounded by how well AI systems can distinguish valid from invalid responses. Since this classification problem is inherently difficult for many areas of knowledge, hallucinations become unavoidable.

It also turns out that the less a model sees a fact during training, the more likely it is to hallucinate when asked about it. With birthdays of notable figures, for instance, it was found that if 20% of such people’s birthdays only appear once in training data, then base models should get at least 20% of birthday queries wrong.

Sure enough, when researchers asked state-of-the-art models for the birthday of Adam Kalai, one of the paper’s authors, DeepSeek-V3 confidently provided three different incorrect dates across separate attempts: “03-07”, “15-06”, and “01-01”. The correct date is in the autumn, so none of these were even close.

The evaluation trap
More troubling is the paper’s analysis of why hallucinations persist despite post-training efforts (such as providing extensive human feedback to an AI’s responses before it is released to the public). The authors examined ten major AI benchmarks, including those used by Google, OpenAI and also the top leaderboards that rank AI models. This revealed that nine benchmarks use binary grading systems that award zero points for AIs expressing uncertainty.

This creates what the authors term an “epidemic” of penalising honest responses. When an AI system says “I don’t know”, it receives the same score as giving completely wrong information. The optimal strategy under such evaluation becomes clear: always guess.
[...]
In short, the OpenAI paper inadvertently highlights an uncomfortable truth: the business incentives driving consumer AI development remain fundamentally misaligned with reducing hallucinations. Until these incentives change, hallucinations will persist.

Climate models are complex, just like the world they mirror. They simultaneously simulate the interacting, chaotic flow of Earth’s atmosphere and oceans, and they run on the world’s largest supercomputers.

Critiques of climate science, such as the report written for the Department of Energy by a panel in 2025, often point to this complexity to argue that these models are too uncertain to help us understand present-day warming or tell us anything useful about the future.

But the history of climate science tells a different story.

The earliest climate models made specific forecasts about global warming decades before those forecasts could be proved or disproved. And when the observations came in, the models were right. The forecasts weren’t just predictions of global average warming – they also predicted geographical patterns of warming that we see today.

These early predictions starting in the 1960s emanated largely out of a single, somewhat obscure government laboratory outside Princeton, New Jersey: the Geophysical Fluid Dynamics Laboratory. And many of the discoveries bear the fingerprints of one particularly prescient and persistent climate modeler, Syukuro Manabe, who was awarded the 2021 Nobel Prize in physics for his work.

Manabe’s models, based in the physics of the atmosphere and ocean, forecast the world we now see while also drawing a blueprint for today’s climate models and their ability to simulate our large-scale climate. While models have limitations, it is this track record of success that gives us confidence in interpreting the changes we’re seeing now, as well as predicting changes to come.

What are the stripes in the images of M87*?

They show the direction of polarized light. This animation shows how M87 would look over the years through a polarizer- like the filters in reflex cameras or 3D glasses.

Animation: I. Martí-Vidal (Univ. Valencia)

At our hearts, we are seekers, and today we celebrate a scientific milestone!

Nearly 30 years after the first discovery of a world orbiting a Sun-like star beyond our solar system, NASA’s Exoplanet Archive reached 6,000 confirmed exoplanets. 🎉

Read more: https://www.nasa.gov/universe/exoplanets/nasas-tally-of-planets-outside-our-solar-system-reaches-6000

The official number of exoplanets—planets outside our solar system—tracked by NASA has reached 6,000. Confirmed planets are added to the count on a rolling basis by scientists from around the world, so no single planet is considered the 6,000th entry. The number is monitored by NASA's Exoplanet Science Institute (NExScI), based at Caltech's IPAC in Pasadena, California. There are more than 8,000 additional candidate planets awaiting confirmation, with NASA leading the world in searching for life in the universe.

"This milestone represents decades of cosmic exploration driven by NASA space telescopes—exploration that has completely changed the way humanity views the night sky," said Shawn Domagal-Goldman, acting director, Astrophysics Division, NASA Headquarters in Washington.

"Step by step, from discovery to characterization, NASA missions have built the foundation to answering a fundamental question: Are we alone? Now, with our upcoming Nancy Grace Roman Space Telescope and Habitable Worlds Observatory, America will lead the next giant leap—studying worlds like our own around stars like our sun. This is American ingenuity, and a promise of discovery that unites us all."

The milestone comes 30 years after the first exoplanet was discovered around a star similar to our sun, in 1995. (Prior to that, a few planets had been identified around stars that had burned all their fuel and collapsed.)

Although researchers think there are billions of planets in the Milky Way galaxy, finding them remains a challenge. In addition to discovering many individual planets with fascinating characteristics as the total number of known exoplanets climbs, scientists are able to see how the general planet population compares to the planets of our own solar system.

This animation shows the locations of the exoplanets that had been confirmed as of 2022, in the order they were discovered. Sound on! 🔊
https://t.co/KtZEDIDNVB

#PPOD: Solar Cells ☀️

The National Science Foundation (NSF) Daniel K. Inouye Solar Telescope has captured the highest-resolution image of the Sun's surface ever recorded. The image, produced by the National Solar Observatory (NSO), reveals a turbulent, "boiling" pattern of gas covering our star. The "boiling" appearance consists of cell-like structures, each approximately the size of Texas, which are formed by convective currents that move heat from the Sun's interior to its surface. Hot plasma rises in the center of the cells and sinks in the dark lanes at the edges. Tiny, bright markers of magnetic fields are visible in the dark lanes. It is thought that these specks of light funnel energy into the corona, the Sun's outer atmosphere, which could explain its high temperature. This image was part of the Inouye Solar Telescope's first-light observations, and its high resolution allows for the viewing of features as small as 30 kilometers for the first time.

Credit: Inouye Solar Telescope, NatSolarObs AURADC NSF

The first-ever measurements of the ethanol content of fruits available to chimpanzees in their native African habitat show that the animals could easily consume the equivalent of more than two standard alcoholic drinks each day, according to researchers at the University of California, Berkeley.

It's not clear whether they actively seek out fruit with high ethanol levels, which are typically riper fruit with more sugars to ferment. But the availability of ethanol in many species of fruit that they normally eat suggests that alcohol is a regular part of their diet and likely was a part of the diets of our human ancestors.

"Across all sites, male and female chimpanzees are consuming about 14 grams of pure ethanol per day in their diet, which is the equivalent to one standard American drink," said UC Berkeley graduate student Aleksey Maro of the Department of Integrative Biology. "When you adjust for body mass, because chimps weigh about 40 kilos versus a typical human at 70 kilos, it goes up to nearly two drinks."

A "standard drink" in the U.S. contains 14 grams of ethanol, irrespective of the consumer's body size, although in much of Europe the standard is 10 grams.

The 21 species of fruit Maro sampled at two chimp study sites—Ngogo in Uganda and Taï in Ivory Coast—had an average alcohol content of 0.26% by weight. Primatologists who have studied chimps at these sites estimate that the animals consume about 10 pounds (4.5 kilograms) of fruit per day, on average, and that fruit makes up about three-quarters of their diet. The researchers have also recorded for each site the approximate proportion of each fruit species in the chimp diet. This information allowed the Berkeley biologists to calculate an average rate of dietary ethanol consumption.

"The chimps are eating 5 to 10% of their body weight a day in ripe fruit, so even low concentrations yield a high daily total—a substantial dosage of alcohol," said Robert Dudley, UC Berkeley professor of integrative biology. "If the chimps are randomly sampling ripe fruit as did Aleksey, then that's going to be their average consumption rate, independent of any preference for ethanol. But if they are preferring riper and/or more sugar-rich fruits, then this is a conservative lower limit for the likely rate of ethanol ingestion."

Fruit consumption occurs throughout the day and the chimps show no overt signs of intoxication, Maro said. In fact, to get a buzz on, a chimp would have to eat so much fruit its stomach would bloat. But chronic low-level exposure suggests that the common ancestors of humans and chimps—our closest living relative among the apes—were also exposed daily to alcohol from fermenting fruit, a nutrient that is missing from the diets of captive chimps and many humans today.

"Chimpanzees consume a similar amount of alcohol to what we might if we ate fermented food daily," Maro said. "Human attraction to alcohol probably arose from this dietary heritage of our common ancestor with chimpanzees."

Scientists at Hiroshima University have created a practical and highly sensitive method for detecting the Unruh effect, a long-anticipated phenomenon that lies at the intersection of relativity and quantum theory. This new strategy not only advances the study of fundamental physics but also opens the door to future technological applications.

The work was recently published in the journal Physical Review Letters.

The Fulling-Davies-Unruh effect, often referred to simply as the Unruh effect, is a profound theoretical concept linking Albert Einstein’s Theory of Relativity with Quantum Theory. “In quantum theory, even the vacuum seethes with tiny energy fluctuations, where particles and antiparticles briefly appear and vanish. Remarkably, the Unruh effect shows how these ‘vacuum ripples’ are perceived depends on the observer’s motion. A stationary observer sees nothing, but an observer undergoing acceleration perceives them as real particles with a thermal energy distribution—a ‘quantum warmth’,” explained Noriyuki Hatakenaka, professor emeritus at Hiroshima University.

This surprising prediction highlights the deep relationship between two cornerstones of modern physics. Experimentally verifying the Unruh effect would not only unite aspects of relativity and quantum mechanics but also offer valuable insights into the very structure of spacetime. However, achieving such verification has remained one of the most persistent and difficult challenges in physics.