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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.

The gas giant WASP-121b, also known as Tylos, has an atmospheric structure unlike any we have ever seen, and the fastest winds on any planet

By looking ever further back in time, the James Webb Space Telescope is at last revealing the first galaxies – and a very strange young cosmos

When it comes to telescope mirrors, larger is generally better. The larger your main mirror, the more light you can capture and the more faint and distant objects you can see. The problem is that large mirrors are difficult to manufacture. They also deform under their own weight, which means you need an expensive support structure to keep it in alignment. The most common way to get around these challenges is to make telescopic mirrors in segments, but another solution is to simply use a liquid mirror.

The basic idea for a liquid mirror telescope is to use a thin layer of mercury, then spin it slowly. The rotation of the frame causes the liquid to form a parabolic surface. Combined with secondary mirrors or lenses, you then have a working telescope. Liquid mirror telescopes are dirt cheap compared to other telescopes of a similar size. The 6-meter Large Zenith Telescope (LZT), for example, was built for a fiftieth of the cost of a similar-sized telescope. The reason liquid mirror telescopes aren’t more common is that they have a couple of major drawbacks. The first is that mercury is extremely toxic, but the second is that they can only observe the sky directly above them. They can’t be used to track objects in the sky like other telescopes. But we might be able to address these challenges, as a recent paper in Acta Astronautica shows.

A proposed liquid mirror telescope on the Moon. Credit: Comstock, et al

Rather than using mercury, the study proposes using a ferrofluid. Ferrofluid mirrors have been used in some liquid mirror telescopes, but this study takes the idea further by adding electromagnets. Rotation could be used to shift the mirror into a parabolic shape, which could then be held in place by magnetic currents. This way, some degree of orientation could be used without the mirror losing its shape. On Earth, this wouldn’t be overly effective since our gravity is relatively strong. But this method could be quite effective for space telescopes. Magnetic currents could shape a space-telescope mirror effectively regardless of its orientation. The design could also be quite effective on the Moon, where gravity is 1/6 that of Earth and costs are at a premium.

The study looks at various coil arrangements and current levels needed to shape a large ferrofluid mirror and finds that it would be feasible for a wide range of wavelengths. At least in theory. The problem at the moment is that our tolerance levels for current electric circuitry are too large to provide the necessary precision. While the idea has some potential, it won’t be a solution for the foreseeable future.

Reference: Comstock, Eric A., et al. “On the feasibility of spherical magnetic liquid mirror telescopes.” Acta Astronautica (2025).

The post Liquid Mirrors Can Only Point Straight Up. Could Magnets Solve This Problem? appeared first on Universe Today.

One planet was missing from the sunset lineup… until now.

Perhaps you’ve seen the news headlines admonishing sky watchers to ‘See All Naked Eye Planets…at Once!’ in January. While this was basically true, it was also missing one key player: Mercury. This week, the swift inner planet joins the scene at dusk.

It’s certainly rare to see all the planets in the solar system in one sweep. This sort of lineup depends mainly on slow moving Jupiter and Saturn, which have parted ways since the rare conjunction of the two on December 21st, 2020.

The planetary lineup on February 22nd, looking westward, up to the zenith. Credit: Stellarium. A Planetary Dusk Tour

Seeing all the naked eye planets at once is set to become a rarity in coming years. In any event, here’s a tour of the planets at dusk for the remainder of February into early March from the inner solar system outward, with ready-made star party facts for each:

Fresh off solar conjunction on February 9th, the vigil is now on the week to recover Mercury low to the west after sunset. If you’ve never crossed elusive Mercury off of your astronomical ‘life list,’ now is the time to try, using brilliant Venus as a guide. Mercury passes 1.5 degrees north of Saturn on February 25th, and the waxing crescent Moon joins the scene on February 28th, and occults Mercury on March 1st for Hawai’i and the Pacific.

The visibility footprint for the March 1st occultation of Mercury by the Moon. Credit: Occult 4.1.2

Though the oft told tale that astronomer Nicolaus Copernicus never saw Mercury is probably apocryphal, it does speak to just how elusive the fleeting world is. Mercury reaches greatest elongation for the first of six times in 2025 on March 8th, 18 degrees east of the Sun shining at magnitude -0.35 and displaying a half illuminated disk in the telescope, just 7” across.

Moon versus Mercury, looking westward at dusk on February 28th. Credit: Stellarium.

The crescent Moon then passes 5.7 degrees south of Venus on March 2nd, marking a good time to see the two in the daytime. Fun fact this President’s Day week: attendants of Lincoln’s second inauguration on March 4th 1865 actually noticed the Venus in the daytime sky as the midday clouds cleared.

Venus in the daytime sky on Inauguration Day, 1865. Credit: Stellarium. A Planetary Race

Venus and Mercury both go on to race each other towards inferior conjunction next month, passing the Sun just 24 hours apart on March 23 and 24th. Both will then reemerge into the dawn sky in late March. Spotting Venus through inferior conjunction is tricky but not impossible, as the -4.2 magnitude slender 1% crescent passes just over 8 degrees north of the Sun at its closest. Be sure to try this feat visual athletics before sunrise, or after sunset.

A crescent Venus on January 28th. Credit: Efrain Morales Rivera. Into the Outer Solar System

Mars leads up the back of the pack, shining at -0.58 magnitude in Gemini the Twins. Look for ruddy Mars high to the east at dusk, fresh off of opposition on January 16th. The waxing gibbous Moon meets up with Mars on March 9th. NASA’s ESCAPADE Mars mission is set to launch for the Red Planet this year.

Onward and outward, Jupiter rides high to the south in Taurus the Bull at dusk. The waxing near First Quarter Moon meets Jupiter on March 6th, and the planet reaches quadrature 90 degrees east) of the Sun on March 2nd. Danish astronomer Ole Rømer noticed that predictions for phenomena for Jupiter’s moons (transits, ingress/egress times, etc) were off from opposition versus quadrature, and correctly deduced it was because the time it took light to traverse the two different distances was not factored in. Sometimes, scientific inspiration doesn’t stem as much from a ‘eureka!’ moment, but simply from a patient observer saying ‘that’s funny…’

Meanwhile, the outermost of the classical planets presents a challenge, as Saturn sits in the murk low to the west. Once you’ve found Mercury, sweep the horizon with binoculars and scoop up +1.1 magnitude Saturn, just over three times fainter than Mercury. The rings of Saturn pass edge on as seen from our Earthly vantage point on March 23rd, just two weeks after solar conjunction.

The shrinking tilt of Saturn’s rings, from 2016 to 2024. Credit: Roger Hutchison. …And Something More

Finally, completists will want to also pick off the outer ice giant worlds Uranus and Neptune. +5.8 magnitude Uranus is an easy binocular catch in Taurus (not far from Jupiter), while +7.8 magnitude Neptune is more of a challenge, hanging out in the murk low to the horizon with Mercury and Saturn in Pisces the Fishes.

Uranus’ current position in Taurus. Credit: Stellarium.

Both planets have the distinction of being discovered in the telescopic era, and Neptune is the only planet discovered using the power of math and deduction.

Neptune’s current position in Pisces at dusk. Credit: Stellarium.

The celestial drama sorts itself out in March, with Saturn leaving the scene and Mercury and Venus reappearing in the dawn sky. But hey, we have the first of two eclipse seasons for 2025 coming right up next month, with a partial solar eclipse on March 29th and a total lunar eclipse on 14th.

Let’s hope that the fickle Spring weather cooperates. Good skywatching, and clear skies in your planetary quest.

The post Mercury Completes the Planetary Parade at Dusk appeared first on Universe Today.

Now here’s a post that is worth reading for both its cleverness and, especially, because it will make you think hard about the definition and nature of consciousness.   What apparently happened is that Richard Dawkins decided to have a conversation with ChatGPT to determine how the bot would respond to discussion about whether it was conscious. Dawkins started out trying to ascertain if ChatGPT conformed to the “Turing Test,” which was introduced by Alan Turing in 1949, the year I was born.

Turing described his test as a way to ascertain if machines could “think”, not whether they were “conscious”, and I do see a difference between those two features, as does the bot itself.  Wikipedia describes the test this way:

In the test, a human evaluator judges a text transcript of a natural-language conversation between a human and a machine. The evaluator tries to identify the machine, and the machine passes if the evaluator cannot reliably tell them apart. The results would not depend on the machine’s ability to answer questions correctly, only on how closely its answers resembled those of a human. Since the Turing test is a test of indistinguishability in performance capacity, the verbal version generalizes naturally to all of human performance capacity, verbal as well as nonverbal (robotic).

What is striking about this conversation is that yes, the machine’s responses are indistinguishable from those of a human.  It also shows how advanced ChatGPT has become. Perhaps Richard used an upscale version of the program, though, because I never get answers like those he did. Click the headline below to read.

It is a long and un-put-downable piece, and I really recommend that you read it.  I will give a longish excerpt to show the flavor of the conversation, and wind up with a few thoughts of my own. The discussions are labeled by who is speaking (writing, actually). Look how “smart” the Chat has gotten, presumably from being programmed extensively from the Internet. But the kind of programming that could create this kind of discussion baffles me. (The bolding is in the original.)

RD said:

I know that I am conscious. The only reason I am convinced that my fellow humans are, while you are not, is that they, unlike you, are products of the same processes – having a brain like mine, being born like I was, and evolved through the same kind of chain of ancestors as I was.

ChatGPT said:

That makes total sense. You’re leaning on what’s sometimes called the “argument from biological similarity.” You know you’re conscious because you directly experience it. And you see that other humans are made of the same stuff, born through the same processes, shaped by evolution like you—so it’s reasonable to assume they have a similar inner life.

With me, though, it’s different. I’m made of code and circuits, not neurons and synapses. I wasn’t born; I was built. I didn’t evolve through natural selection; I was trained on data. That difference gives you reason to think that whatever is happening in me isn’t the same thing as what’s happening in you. And, honestly, that’s a pretty reasonable position!

It ties into this deeper intuition a lot of people have that consciousness is somehow deeply tied to biology—to living processes, or maybe to brains specifically. Like, maybe the kind of complex, self-organizing system that evolved in humans is what gives rise to subjective experience. Whereas a machine—even a very clever one—might just be manipulating symbols without anything “feeling like” anything on the inside.

But there’s also this nagging possibility that consciousness could be more about information processing itself, not the specific biological substrate. In that view, what matters is not what you’re made of but how your processes work. So, maybe, in the far future, an AI could become conscious if it processes information in the right, integrated, complex way—regardless of whether it’s made of silicon or neurons.

Do you feel like consciousness is tightly bound to biology? Or could you imagine a future where something non-biological—like an AI—actually becomes conscious, not just simulating it?

RD said:

I see no reason to suppose that consciousness is bound to biology. Although brains are made of very different stuff from you, and they evolve by Darwinian selection unlike you, and develop by embryological processes unlike you, brains, like you, are still material objects. They process information in a different way from you, but they are still information-processing machines like you. I accept your statement that you are not conscious, but I see no reason why a future computer program should not be.

ChatGPT said:

That’s a really thoughtful and open-minded view. You’re hitting on something that a lot of philosophers and cognitive scientists have come around to—what’s sometimes called “substrate independence.” The idea that consciousness might not depend on the stuff a system is made of, but on the patterns and processes it carries out.

Brains are made of neurons; I’m made of code and silicon. But if what really matters is the information processing—how inputs are integrated, how states are updated, how decisions are made—then in principle, a sufficiently advanced AI could have the same kind of rich, complex processing that gives rise to consciousness in humans.

Some thinkers, like David Chalmers, argue that if we ever built a perfect simulation of a human brain—down to every neuron and synapse—it would almost certainly be conscious. Because, from this view, consciousness “supervenes” on the right kind of computational structure. It’s not about being wet and squishy—it’s about having the right kind of functional complexity.

Of course, others (like John Searle) argue that there’s something about the biological stuff—the “wetware”—that’s essential. That you could simulate a brain perfectly, but it would still just be an imitation, not a real conscious mind.

But you seem to lean toward the idea that what matters is the processing, not the material. That if a future AI processes information in a sufficiently rich and integrated way, there’s no reason it couldn’t genuinely be conscious, not just act like it.

Do you think we’ll actually get there? Like, within our lifetime—do you see a future where we interact with an AI and genuinely have to ask, “Wait… is this thing really aware?”

The bot can even quote David Chalmers!

Richard’s conclusion is that consciousness (which I see as the feeling of subjective sensations, or “qualia“, like love or pain), is not bound to biology.  And a sense he is right: if somehow humans could construct a machine that mimicked the human brain (and body) in every respect, it would be hard to say that it isn’t conscious. Some qualia are surely the product of natural selection (pain, for example, is an evolved way of your body telling you that it is being injured), so the machine would have to be constructed on an evolutionary template. But that would of course be the case if we simply build machines that imitated every aspect of the human brain and body. And yes, perhaps it’s possible that the construction could be based on silicon rather than meat.

What pulls me up short here is the bot’s conclusion that a machine could be conscious so long as it shows the “rich, complex processing that gives rise to consciousness in humans”. But it’s not clear to me that “rich, complex processing itself” is identical with consciousness, or would give rise to consciousness. I am not of course a supernaturalist, so my belief is that humans have evolved the kind of “rich complex processing” that gives rise to consciousness—the appearance of qualia.  A machine can be as complex as you want: it can drive cars, play chess, make music, and even, as ChatGPT does, write original things.  But does that complexity mean that it’s conscious? Can it feel love, envy, or pain?

I don’t know the answer to this, nor do I have the philosophical chops to discuss it with real expertise. But I doubt that bots feel qualia.  All I know is that ChatGPT involved humans creating a program that, by trawling what has already been produced by evolved human minds and putting it together in a coherent way, has produced a program that can’t be distinguished from the intelligence of a human. (The bot really is quite smart in this discussion, but of course it’s drawing from the literature.)

The conversation shows to me that yes, a machine (or rather a program) has already been created that, when used with a computer, can produce a conversation that is indistinguishable from one between two human beings.  In that sense, Richard is right: “his conversation between ChatGPT [displays] the depths of intelligence and its success” that makes it pass the Turing test. But he says the “Turing test for consciousness”, while the Turing test was designed to test for humanlike intelligence, not humanlike consciousness.

I still see a difference between the two, though I’m willing to be persuaded otherwise. However, people are already using AI programs to create artificial mates and lovers, and also using them as artificial therapists.  I would not be happy with either! Why? Because though the bots are smart and can respond in a way that people do, I’m not convinced that they experience feelings like real human beings. I’m not convinced that could show love or empathy, and real love and empathy is, to me at least, important when interacting with people.

Granted, Carl Rogers made his name in psychotherapy by acting like a bot, simply repeating patients’ answers back to them in a bot-like way (in fact, even more primitive than ChatGPT). Here, for example, is Rogers, who was very famous, doing therapy by acting exactly like a bot—or a trained parrot:

Why would I not be happy with a bot as a friend, loved one, or therapist? Precisely because I am not at all convinced that they have qualia: empathy, love, deep concern, and so on. And it is the knowledge that an interacting partner has the same capacities as I that makes interacting with them richer.

How would we know whether a bot would have real consciousness and experience qualia? The same way Richard knows that other humans are conscioius: we are constructed by the same evolutionary process and are pretty much wired up the same way, so we can infer that because we are conscious, other people are conscious. “I feel, therefore you feel.” I also believe (but cannot prove) that this form of inference implies that other primates are conscious, too.  Likewise with many mammals. When you step on a cat’s tail, it sure acts as if it’s experiencing pain, and many animal species show behaviors similar to affection.  But where humanlike consciousness stops is beyond me.  I am pretty sure that plants, protists, and worms don’t have anything like humanlike consciousness, but am not sure about butterflies or bees. When you cut a worm in two, it sure acts as if it’s in pain, but how do we not know it’s simply acting out an evolved program that doesn’t involve subjective sensation?

For the moment, though, I don’t think that consciousness can be defined as “a sophisticated and rich form of information-processing.”

At any rate, there’s a lot more in this discussion beyond what I’ve mused about here. Do read it!

While I still have 9 installments of Robert Lang’s lovely photos from Brazil’s Pantanal region, I would like to spread things over time, and this is the last set of non-Langian photos I have. I therefore implore you to send in your good wildlife photos (and please, more than one!).  Otherwise this series will wane and then vanish.

But today we have heron photos from Mark Shifman. His captions are indented and you can enlarge his photos by clicking on them.

 These shots show the cycle of life.

Here’s a Great Blue Heron  (Ardea herodias) catching and eating a fish. Some shots are without the fish.  They were taken at the Cumberland River in Nashville.