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Researchers have demonstrated a new technique that uses light to tune the optical properties of quantum dots -- making the process faster, more energy-efficient and environmentally sustainable -- without compromising material quality.

Researchers have demonstrated a new technique that uses light to tune the optical properties of quantum dots -- making the process faster, more energy-efficient and environmentally sustainable -- without compromising material quality.

Researchers developed a new system for turning used coffee grounds into a paste, which they use to 3D print objects, such as packing materials and a vase. They inoculate the paste with Reishi mushroom spores, which turn the coffee grounds into a resilient, fully compostable alternative to plastics.

In the world of soft robotics and wearable technology, sheet-based fluidic devices are revolutionizing how lightweight, flexible and multifunctional systems are designed. But with innovation comes challenges, particularly in understanding and controlling failure in these devices. A new study by mechanical engineers explores how programmed failure in heat-sealable, sheet-based systems can be used to protect devices, enable complex sequencing of actions and even streamline control mechanisms.

In the world of soft robotics and wearable technology, sheet-based fluidic devices are revolutionizing how lightweight, flexible and multifunctional systems are designed. But with innovation comes challenges, particularly in understanding and controlling failure in these devices. A new study by mechanical engineers explores how programmed failure in heat-sealable, sheet-based systems can be used to protect devices, enable complex sequencing of actions and even streamline control mechanisms.

The often stereotyped and offensive responses from AI chatbots role-playing as humans can be explained by flaws in how large language models attempt to portray demographic identities

The Phoenix Cluster is one of the most massive galaxy clusters known. Astronomers have identified 42 member galaxies so far, yet there could be as many as 1,000 in the cluster. Because of its size and its age, it should be finished with the vigorous star formation characteristic of young galaxies.

But it’s not.

Star formation needs cold, dense gas. Hot gas resists collapsing into stellar cores, which become protostars and then main sequence stars. Old galaxies and clusters have either used up their cold gas or had it stripped away. These are called ‘quenched’ galaxies. In terms of star formation, galaxies can be classified as red sequence, meaning old and quenched, or blue cloud, meaning there’s more active star formation.

The Phoenix Cluster’s central galaxy is about 5.8 billion light-years away and should be mostly done with star formation. Many galaxy clusters have a region of hot gas in the intracluster medium (ICM). In a typical galaxy, this gas cools down and feeds star formation. However, observations show that the rate of star formation in these galaxies is remarkably low, and there’s no evidence of the cold gas. Astronomers call this discrepancy the “cooling flow problem,” and it leads to this question: Why isn’t the ICM cooling and forming new stars?

The dominant answer to this is that black hole jets from active galactic nuclei are heating the gas and preventing it from forming stars.

The Phoenix Cluster’s central galaxy should be mostly done with star formation. Yet it has an intensely bright core typical of vigorous star formation. Somehow, the Phoenix Cluster has a source of cold gas that’s fuelling the star birth. Did it generate itself somehow? Is it funnelling in from younger galaxies?

In new research, scientists used the JWST to probe the cluster’s heart. They did so because previous observations with other telescopes showed that the core was extraordinarily bright, indicating ferocious star birth. Since this contradicted what astronomers think they know about clusters like this, their curiosity was piqued.

The research, published in Nature, is titled “Directly imaging the cooling flow in the Phoenix cluster.” The lead author is Michael Reefe, a physics graduate student at MIT’s Kavli Institute for Astrophysics and Space Research.

This older image of the Phoenix Cluster (SPT-CLJ2344-4243) combines Chandra and Hubble’s X-ray, ultraviolet, and optical wavelengths. In this new research, the team of scientists used the JWST’s infrared capabilities to try to understand Phoenix better. Image Credit: By X-ray: NASA/CXC/MIT/M.McDonald et al; Optical: NASA/STScI – https://chandra.harvard.edu/photo/2015/phoenix/ (image link), Public Domain, https://commons.wikimedia.org/w/index.php?curid=45952066

Michael McDonald, associate professor of physics at MIT and co-author of this research, led the research team that discovered the Phoenix Cluster in 2010 using the South Pole Telescope. Two years later, they observed it again with multiple telescopes. They found that the central galaxy in the cluster was unexpectedly bright due to extreme star formation. The researchers said that up to 1,000 stars could be forming each year, an astounding number compared to the Milky Way, which forms fewer than 10 stars per year according to some research.

In previous observations, astronomers have found some very hot gas and some very cold gas in the Phoenix Cluster. They have observed pockets of ultrahot gas measuring about 1 million degrees Fahrenheit and regions of extremely cold gas measuring only 10 kelvins, or 10 degrees above absolute zero. Hot gas is not unusual since supermassive black holes (SMBHs) can emit extremely energetic jets that can heat gas. When a galaxy is young, some of this gas cools and forms stars. The Phoenix Cluster’s central galaxy also has some cool gas. Previous observations showed that there was no in-between warm gas, which is odd. Is there an answer to the cooling flow problem in the Phoenix Cluster?

The researchers reasoned that if the Phoenix central galaxy is somehow generating the detected cold gas, then there must be warm gas that’s intermediate between the hot gas and the cold gas. This is where the JWST enters the picture.

The JWST, with its powerful infrared capabilities, did find some warm gas. That shows that the cluster is able to generate the cold gas needed for star formation because the warm gas is evidence of a transition between temperature extremes.

New JWST observations, based on neon emissions, provided the first large-scale map of gas at temperatures between 100,000 and 1,000,000 Kelvin in the Phoenix Cluster. They used the Medium-Resolution Spectrometer on MIRI and collected 12 hours of infrared data. They were looking for a specific wavelength of light emitted by neon at around 300,000 K, or 540,000 F. This shows the presence of the intermediate warm gas that would be evidence of cooling.

Critically, the neon is co-spatial with other features like the coolest gas and the sites of active star formation. This is evidence supporting a direct link between intermediate gas, its cooling, and star formation.

“This 300,000-degree gas is like a neon sign that’s glowing in a specific wavelength of light, and we could see clumps and filaments of it throughout our entire field of view,” lead author Reefe said in a press release. “You could see it everywhere.”

The three panels in this figure from the study go to the heart of the research. They’re maps of the [Ne VI]-emitting coronal gas in the central galaxy of the Phoenix cluster overlaid with the hotter and colder gas phases and starlight. (a) shows Ne VI flux, which indicates cooling gas. (b) shows an [O II] image of the central galaxy of the Phoenix cluster in the greyscale using data from the HST Advanced Camera for Surveys. It indicates star formation. (c) shows young, actively star-forming regions in blue. Image Credit: Reefe et al. 2025

“For the first time, we have a complete picture of the hot-to-warm-to-cold phase in star formation, which has really never been observed in any galaxy,” said Reefe. “There is a halo of this intermediate gas everywhere that we can see.”

The fact that astronomers were unable to see the telltale warm gas in the Phoenix Cluster doesn’t mean it wasn’t there. The JWST gives researchers their best look at galaxies, uncovering details that were previously hidden. Still, the question that has to be asked is whether Phoenix is special. Will the JWST find the telltale warm gas in other galaxies?

“The question now is, why this system?” added co-author McDonald. “This huge starburst could be something every cluster goes through at some point, but we’re only seeing it happen currently in one cluster. The other possibility is that there’s something divergent about this system, and the Phoenix went down a path that other systems don’t go. That would be interesting to explore.”

“Previous to the Phoenix, the most star-forming galaxy cluster in the universe had about 100 stars per year, and even that was an outlier. The typical number is one-ish,” McDonald said. “The Phoenix is really offset from the rest of the population.”

This brings us to one of the unanswered questions about old galaxies. They should be quenched or “red and dead,” but all of them aren’t. Where did this cold gas come from? Did it come from outside these galaxies?

“The question has been: Where did this cold gas come from?” McDonald said. “It’s not a given that hot gas will ever cool, because there could be black hole or supernova feedback. So, there are a few viable options, the simplest being that this cold gas was flung into the center from other nearby galaxies. The other is that this gas somehow is directly cooling from the hot gas in the core.”

The fact that the [Ne VI] emissions are cospatial with the sites of active star formation suggests a recent episode of rapid gas cooling, creating a spike in cooling. The researchers say this extreme cooling us generating 20,000 solar masses of cold gas each year. That shows that the galaxy is able to supply its own cold gas for star formation and that it’s not coming from elsewhere. The question is, how?

The results suggest that somehow, the central black hole is actually promoting cooling the gas rather than heating it. “These data provide a large-scale map of gas at temperatures between 105 kelvin and 106 kelvin in a cluster core and highlight the critical role that black hole feedback has in not only regulating cooling but also promoting it,” the authors write. “

An artist’s conception of a supermassive black hole’s jets. These jets may play a role in cooling gas rather than heating it. Image Credit: NASA / Dana Berry / SkyWorks Digital

The research answers part of the question that the Phoenix Cluster poses.

“If short-lived cooling episodes are common in the galaxy cluster population, providing the necessary fuel for ongoing AGN feedback, then Phoenix provides a unique window into this critically important, but rarely captured, process for understanding the formation of the most massive galaxies in the Universe,” the authors write in their conclusion.

“I think we understand pretty completely what is going on, in terms of what is generating all these stars,” McDonald said. “We don’t understand why. But this new work has opened a new way to observe these systems and understand them better.”

• Press Release: Study reveals the Phoenix galaxy cluster in the act of extreme cooling
• Research: Directly imaging the cooling flow in the Phoenix cluster

The post This Ancient Galaxy Cluster is Still Forming Stars When it Should be ‘Red and Dead’ appeared first on Universe Today.

We typically think of the Oort cloud as scattered ice balls floating far from the Sun, yet still tied to it gravitationally. Occasionally, some wayward gravitational perturbation will knock one of them a weird way and create a long-period comet, which might briefly delight us lowly humans by providing something interesting in the sky to look at. But what the Oort cloud actually looks like and how it is affected by forces greater than just our solar system has remained somewhat of a mystery. A new paper from researchers at the Southwest Research Institute and the American Museum of Natural History tries to shine a light on what this invisible part of the solar system looks like – at least the part that is only 1,000 to 10,000 times farther away from the Sun as Earth is.

That part called the “inner” Oort cloud is considered slightly more populated than the “outer” Oort cloud, which ranges from 10,000 AU to 100,000 AU. Overall, potentially trillions of icy bodies are thought to be floating deep in space, though we only ever see the ones that show up in the inner solar system as long-period comets. 

Estimating the cloud’s structure requires more than understanding the planet’s gravitational forces. While they still have an impact, there is a larger player in the orbital mechanics of these icy rocks—the galaxy itself.

There’s a concept known as the “Galactic tide”. As our solar system moves through the galaxy, it is subjected to gravitational forces of other objects, like stars and black holes, that are closer or farther away from it. Like Earth’s Moon forces the water on the surface towards it due to its gravity, the galactic center, where most of the galaxy’s mass is, affects large objects in our solar system.

Fraser discusses the Oort cloud, the mysterious region where comets come from.

For the planets, this influence is drowned out by their gravitational bond to the Sun. But for Oort cloud objects, it plays a major role in determining their positioning. New long-period comets are formed when a nuance in the galactic tide either forces them into the inner solar system itself or causes them to collide with one another, sending one off on a trajectory toward the Sun.

Modeling this complex dynamic is hard, and the researchers, including lead author David Nesvorný, had to rely on a supercomputer at NASA to run their analytical model and compare it to previous simulations of the structure of the Oort cloud. They found something intriguing hiding in the data.

According to their model, the Oort cloud looks like a spiral disk about 15,000 au across, offset by the ecliptic by about 30 degrees. But more interestingly, it has two spiral arms that almost make it look like a galaxy.

Spiral arms of the Oort cloud in relation to the ecliptic and galactic planes.
Credit – Nesvorný et al.

These spiral arms, which are located nearly perpendicular to the galaxy’s center, resulting from the influence of the Galactic tide, are represented in the mathematical model by a phenomenon known as the Kozai-Lidov effect. In this quirk of celestial mechanics, large bodies are affected by “Kozai oscillations” that result from the gravitational influence of objects that are much farther away but, in the aggregate, still have an impact on the mechanics of a body.

The changes those oscillations make take a long time, but according to the researcher’s analysis, they almost solely determine the shape of the inner Oort cloud. The gravitational pull of the solar system’s planets or nearby passing stars doesn’t seem to have much effect.

According to the paper, taking a picture of this two-armed spiral will be exceedingly difficult. The authors suggest doing so would either require direct observation of a large number of objects in that space (which is unlikely in the near term) or separation of radiation from those objects that eliminates background and foreground sources so it could track the specific structure.

As of now, neither observational method has any resources dedicated to it. But, if we want to learn more about the home of any potential new comets and their impact on us, it wouldn’t be a bad idea to start planning how to look.

Learn More:
Nesvorný et al – A Spiral Structure in the Inner Oort Cloud
UT – The Oort Cloud Might be More Active Than We Thought
UT – A Star Passed Through the Oort Cloud Less Than 500,000 Years Ago. It Wasn’t the Only One.
UT – There Could Be Captured Planets in the Oort Cloud

Lead Image:
Illustration of the Oort Cloud.
Credit – NASA

The post A Spiral Structure in the Inner Oort Cloud appeared first on Universe Today.

“If I recall correctly, Bertrand Russell was once asked if there were any conceivable evidence which could lead him to a belief in God. He offered something similar to Cleanthes’s suggestion. He was then asked what he would say if, after dying, he were transported to the presence of God; how would he justify his failure on earth to be a believer? ‘I’d say, ‘Not enough evidence, God, not enough evidence!'” (source here)

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All of a sudden Ross Douthat is everywhere, touting his new book  Believe: Why Everyone Should Believe in God.  He wants to make it a best seller, and I’m sure it will be given the number of people still yearning for religion despite its delusional nature.  And, in fact, in his new Free Press article on the book, it’s clear that Douthat wants people to be deluded—or at least wants them to swallow the unevidenced tenets of religion—tenets like a god, Jesus as god’s Alter Ego/son, the Resurrection, and even Heaven and Hell.

The point of this piece is to criticize those people who don’t really accept the full-on Catholicism apparently embraced by Douthat, but rather have embraced what Dan Dennett called “belief in belief”: the notion that while one may not accept religion or its claims oneself, you can still think that religion is good for society as a whole.  We’ve called that the “Little People’s Argument” on this site, because it’s explicitly condescending. And it’s widespread.  I can think right off the bat of several people who appear to embrace belief in belief, including Jordan Peterson and the late Michael Ruse.

Here is the target of Douthat’s lucubrations: those who “convert for some of the wrong reasons” (i.e., who convert, or profess religion, simply because doing so is seen as good for society):

As the author of a new book urging religious belief on, well, everybody, some of these critiques get my hackles up. In writingBelieve: Why Everyone Should Be Religious, which came out this past week, one of my assumptions was that there are a great many people in our culture who hover on the threshold of religion, and they need both reassurance that faith can be reasonable and a friendly but sharp-elbowed shove. But the idea that there exists some kind of ideal version of this process, some perfectly high-minded religious conversion unmediated by secondary influences, political inclinations, tribal loyalties—well, maybe among the greatest saints, but ordinary mortals are always likely to convert for some of the wrong reasons as well as some of the ideal ones.

And what are the wrong reasons? Douthat explains below, getting in a hamhanded swipe at Dawkins, who of course neither believes in the tenets of religion nor thinks religion is a net good, though he is glad he lives in a society that evolved from an earlier Christian one rather than from a Muslim one:

There is, however, a different kind of relationship to religion that does deserve critique. This is the category of person who likes religious ideas when other people believe in them, who wants religion to exist for its civilization-shaping qualities without personally accepting any of its impositions, who draws pleasure from what the late Richard John Neuhaus called “regretful unbelief,” who only really believes in belief.

This is a special temptation for the intellectual. Think of the sociologist who has a thousand data points proving the advantages of joining and belonging and practicing a faith tradition, and an indifferent attitude to the tradition’s truth. The psychologist who stands ready with a thousand fascinating mythic readings of the Old or New Testament but dances away whenever he’s challenged about whether the events in question actually took place. The self-proclaimed “cultural Christian,” whether of the Elon Musk or the Richard Dawkins school, who loves some aspect of the Western inheritance and fears some dark post-Western future—but not enough to actually embrace the West’s metaphysical foundations. The political philosopher with many religious friends and allies in front of whom he would never explicitly use the term “noble lie,” even though you know he’s thinking it.

This tendency is especially suited to eras like our own, when the pendulum has swung away from militant atheism and toward some recognition that religion might be useful for society after all, though it takes somewhat different forms on the right and on the left.

Such people are, says Douthat, “mediocre converts” because they won’t nom the whole hog along with its belief in demons, Gods with supernatural powers, messiahs, and an afterlife either floating on a cloud or burning in eternal flames. And yes, it’s clear that Douthat swallows this stuff:

But I come not just to criticize this tendency, to poke gently at any figure you might recognize in the sketches just above. Some of the critique has to be aimed at the religious as well, for not pushing hard enough against this spirit, not arguing more directly with friends and allies who occupy this space.

We (the religious) like being liked, we appreciate being appreciated, and belief-in-belief provides a useful language to translate between the strangeness of some of our convictions and the world of secular priorities and routines. To talk about faith’s benefits rather than its truth claims. To promise therapeutic advantages when talk of heaven seems embarrassing. To remain in the natural and material and psychological because that way you don’t lose anyone by mentioning the Devil.

All while telling ourselves, of course, that belief-in-belief is one of the paths to real conversion. As, indeed, it quite often is—but only if you don’t make the position feel too comfortable, too much like a well-appointed destination, rather than a station on the way.

Note the reference to the Devil and heaven, which Douthat clearly embrace. What are the evidence for these? Nothing but what’s in the Bible, which of course brings us to the quote that opens this post.  Douthat is willing to bet his whole existence in the claims of a book that’s clearly fictional. The only reason he’s a Catholic is because a.) he sees no way that human reason alone could comprehend the universe without the help of a god and b.) Jesus appeals to him more than does Mohammad or Krishna. (See my posts here, here and here.).  That’s pretty much it.

We all know that much of the Bible is fiction (there was no census that got Jesus from Bethlehem to Nazareth, there was no Exodus nor a pack of Jews wandering in the desert for decades, no record of the dead rising from the grave after the crucifixion and Resurrection, nor even any non-Biblical evidence for a Resurrection. So what makes Douthat so sure that the miracles of Jesus really happened, or that there really is a heaven or hell? Why are miracles so thin on the ground these days when they were ubiquitous when Jesus lived? Why doesn’t God simply show Himself to us if he wants us to believe in Him.

It’s all pure wish-thinking. What he really has is indeed belief in belief, but a form that applies to himself rather than society.  That’s the only way I can explain why he buys this pabulum  and, in this new piece, tries to force it down our throats. Bolding below is mine:

Having spent 15 years as a religious columnist for an audience that includes a great many nonbelievers, I am as guilty of this kind of incomplete evangelization as any other writer. But my new book is a deliberate attempt to leave this kind of halfway argument behind, and to persuade readers to accept religious ideas on their own terms—to transcend the merely sociological and talk directly about why there’s probably a real God with actual demands and expectations, a real supernatural realm that plays some role in human life and history, and yes, a real heaven and a risk of hell.

One of the liberating things about the stranger world we find ourselves in today, the weirder timeline of plagues and populism, psychedelic encounters and AI voices in the air, is that it feels more reasonable to be straightforward in religious argument—to say that of course belief is good for all manner of secondary reasons, but the primary reason is that the core claims of religion are not a fiction, noble or otherwise, but quite probably just the truth. And in that spirit to bless—with whatever warnings and admonitions—the unruly neophyte, the sinful half-believer, and the slightly embarrassing convert.

“Quite probably the truth”! What are his priors? But which religion has the truest core claims? Catholicism, of course, but Douthat doesn’t given us a reason why.  Indeed, he seems to disdain reason in favor of emotion and revelation, the last refuges of the intellectual scoundrel. I needn’t go further: just read Sam Harris’s The End of Faith and Letter to a Christian Nation.

Finally, for people like me who need evidence to embrace a new proposition, what can Douthat say to make me believe things for which there is no evidence—indeed, things like Hell that I find inherently repulsive?  And the biggest question is why the NYT and the Free Press let a man proselytize in its pages about beliefs that lack evidence.  Why don’t they also add ringing defenses of Scientology with its tenets about Xenu:

Xenu (/ˈziːnuː/ ZEE-noo), also called Xemu, is a figure in the Church of Scientology‘s secret “Advanced Technology”, a sacred and esoteric teaching. According to the “Technology”, Xenu was the extraterrestrial ruler of a “Galactic Confederacy” who brought billions of his people to Earth (then known as “Teegeeack”) in DC-8-like spacecraft 75 million years ago, stacked them around volcanoes, and killed them with hydrogen bombs. Official Scientology scriptures hold that the thetans (immortal spirits) of these aliens adhere to humans, causing spiritual harm.

Sounds stupid, doesn’t it? But it is no more believable than the Bible. The only reason we mock Scientology is that we were alive when it was made up.

An innovative circuit design could enable miniature devices, such as microdrones and other microrobotics, to be powered for longer periods of time while staying lightweight and compact. Using miniaturized solid-state batteries, the circuit combines high energy density with an ultra lightweight design.

An innovative circuit design could enable miniature devices, such as microdrones and other microrobotics, to be powered for longer periods of time while staying lightweight and compact. Using miniaturized solid-state batteries, the circuit combines high energy density with an ultra lightweight design.

An international research team has used earth observation radar data to map oil pipeline networks covering a 9000 km2 region in the Niger Delta and pinpoint where crude oil spills have caused the most acute damage to the delicate mangrove ecosystem.

Researchers have discovered a new method by which a catalyst can be used to selectively burn one molecule in a mixture of hydrocarbons -- compounds made of hydrogen and carbon atoms.

Research scientists in Switzerland have developed and tested a robust AI model that automatically segments major anatomic structures in MRI images, independent of sequence. In the study, the model outperformed other publicly available tools.

Astrophysicists have observed our central supermassive black hole. They found the accretion disk is constantly emitting flares without periods of rest. Shorter, faint flares and longer, bright flares appear to be generated by separate processes.

Using mathematical modeling, researchers have discovered that rate-induced tipping, which can happen if an environment changes too fast, can happen even in Daisyworld, a simple daisy-filled ecological model. If the planet heats up or cools down too quickly, all the daisies will go extinct, even if they would otherwise have been able to survive just fine under those conditions. This discovery mirrors similar observations found in other models and observed in real-life ecosystems.

Using mathematical modeling, researchers have discovered that rate-induced tipping, which can happen if an environment changes too fast, can happen even in Daisyworld, a simple daisy-filled ecological model. If the planet heats up or cools down too quickly, all the daisies will go extinct, even if they would otherwise have been able to survive just fine under those conditions. This discovery mirrors similar observations found in other models and observed in real-life ecosystems.

Lobster-eye satellite Einstein Probe captured the X-ray flash from a very elusive celestial pair. The discovery opens a new way to explore how massive stars interact and evolve, confirming the unique power of the mission to uncover fleeting X-ray sources in the sky.

Astronomers have peered through the atmosphere of a planet beyond the Solar System, mapping its 3D structure for the first time. By combining all four telescope units of the European Southern Observatory's Very Large Telescope (ESO's VLT), they found powerful winds carrying chemical elements like iron and titanium, creating intricate weather patterns across the planet's atmosphere. The discovery opens the door for detailed studies of the chemical makeup and weather of other alien worlds.

If you’re of a certain age, you know Alan Alda from his wonderful acting in television shows and in movies. But you may not know of his long-standing interest in science communication and his podcast Clear and Vivid (named for the characteristics that he feels all communication should have.)

Alda and I had a great conversation about the idea that we are made of waves, and what it means for our relationship to the universe. A slimmed-down version of that discussion is now available on his podcast. I hope you enjoy it!

Separately, as promised: to my last post, which covered various ways of depicting and interpreting wave functions, I’ve added explanations of the two quantum wave functions that I placed at the end. Tomorrow I’ll take a step back and consider wave functions from a larger point of view, taking a brief look at what they are (and aren’t), what’s “wavy” (and not) about them, and at their roles in contexts ranging from pre-quantum physics of the 19th century to quantum field theory of the 21st.