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A research team has developed a groundbreaking method for synthesizing perovskite nanocrystals (PNCs), a next-generation semiconductor material, in a more uniform and efficient manner. This study is expected to serve as a key breakthrough in overcoming the complexities of conventional synthesis methods and accelerating the commercialization of various optoelectronic devices, such as light-emitting diodes (LEDs) and solar cells, that utilize nanocrystals.

Researchers have identified the origin of the restoring force that lets elastic crystals return to their original shape.

Groundbreaking study shows machine learning can decode emotions in seven ungulate species. A game-changer for animal welfare? Can artificial intelligence help us understand what animals feel? A pioneering study suggests the answer is yes. Researchers have successfully trained a machine-learning model to distinguish between positive and negative emotions in seven different ungulate species, including cows, pigs, and wild boars. By analyzing the acoustic patterns of their vocalizations, the model achieved an impressive accuracy of 89.49%, marking the first cross-species study to detect emotional valence using AI.

Researchers have pioneered a new catalytic transformation that converts epoxides into fluorinated oxetanes, a coveted but difficult-to-make class of drug molecules that escaped synthetic preparation for years. By unlocking a pathway to these valuable drug scaffolds, this discovery potentially opens the door to new medicines for drug discovery applications.

Researchers have investigated how microbubbles tiny gas bubbles can deliver drugs into cells in a targeted manner using ultrasound. For the first time, they have visualized how tiny cyclic microjets liquid jets generated by microbubbles penetrate the cell membrane enabling the drug uptake.

Perovskite solar cells are highly efficient and low cost in production. However, they still lack stability over the decades under real weather conditions. An international research collaboration has now explored the effects of multiple thermal cycles on microstructures and interactions between different layers of perovskite solar cells. They conclude that thermal stress is the decisive factor in the degradation of metal-halide perovskites. Based on this, they derive the most promising strategies to increase the long-term stability of perovskite solar cells.

Photonics researchers have demonstrated how self-imaging of light, a phenomenon known for nearly two centuries, can be applied to cylindrical systems, facilitating unprecedented control of light's structure with great potential for advanced optical communication systems. In addition, a new type of space-time duality is explored for powerful analogies bridging different fields of optics.

Stars form in Giant Molecular Clouds (GMCs), vast clouds of mostly hydrogen that can span tens of light years. These stellar nurseries can form thousands of stars. Astronomers know this because they observe these regions in the Milky Way and the Magellanic Clouds and watch as stars take shape.

But the Universe is more than 13 billion years old and has been forming stars for almost that entire time. The early Universe was different in notable ways. Was star formation any different in the early Universe?

One of the main differences between the early Universe and the modern Universe is metallicity. Elements heavier than hydrogen and helium, called metals in astronomy, didn’t exist in the very early Universe. Only after massive stars formed and died did the Universe’s metallicity increase. Metallicity affects many different processes, including star formation. Metals help cool down clouds of gas and dust, allowing them to collapse and form stars.

Scientists know a lot about the star formation process, but there are many outstanding questions. One of them concerns star formation in the early, low-metallicity Universe. How different was the star formation process billions of years ago?

“We can’t go back in time to study star formation in the early universe, but we can observe parts of the universe with environments similar to the early universe.”

Kazuki Tokuda, Kyushu University, Japan

New research in The Astrophysical Journal tackled the question. It’s titled “ALMA 0.1 pc View of Molecular Clouds Associated with High-mass Protostellar Systems in the Small Magellanic Cloud: Are Low-metallicity Clouds Filamentary or Not?” The lead author is Kazuki Tokuda, a Post-doctoral fellow in the Department of Earth and Planetary Sciences in the Faculty of Science at Kyushu University in Japan. Tokuda is also affiliated with the National Astronomical Observatory of Japan.

This simulation shows stars forming in a molecular cloud, including the jets emitted by young protostars. Astrophysicists know a lot about the star-formation process, but there are still many questions awaiting comprehensive answers. Video Credit: Mike Grudic/STARFORGE

“Even today our understanding of star formation is still developing, comprehending how stars formed in the earlier universe is even more challenging,” said lead author Tokuda in a press release. “The early universe was quite different from today, mostly populated by hydrogen and helium. Heavier elements formed later in high-mass stars. We can’t go back in time to study star formation in the early universe, but we can observe parts of the universe with environments similar to the early universe.”

One of those places is the Small Magellanic Cloud (SMC), a dwarf galaxy near the Milky Way. The SMC’s metallicity is much lower than the Milky Way’s, containing only about one-fifth as many metals. This makes it analogous to the early Universe about 10 billion years ago.

In the Milky Way, star-forming molecular clouds tend to have a filamentary structure. Astronomers have wondered whether these same filamentary shapes are a universal feature found throughout cosmic time. “To test whether these structures are universal throughout cosmic star formation history, it is crucial to study low-metallicity environments within the Local Group,” the authors explain in their paper. Since the SMC is a close neighbour and also has a low metallicity, it’s a good place to look. However, searching the SMC for these filamentary features has been difficult due to the insufficient spatial resolution of many observatories.

The researchers used the Atacama Large Millimeter-submillimeter Array’s (ALMA) power to examine the SMC and see if it has the same star-forming filamentary structures. They focused on the molecular clouds associated with massive young stellar objects (YSOs) in the (SMC).

This image from the research shows the overall view of the SMC and the positions of the target YSOs. Image Credit: Tokuda et al. 2025.

“In total, we collected and analyzed data from 17 molecular clouds. Each of these molecular clouds had growing baby stars 20 times the mass of our Sun,” said lead author Tokuda in a press release. “We found that about 60% of the molecular clouds we observed had a filamentary structure with a width of about 0.3 light-years, but the remaining 40% had a ‘fluffy’ shape. Furthermore, the temperature inside the filamentary molecular clouds was higher than that of the fluffy molecular clouds.”

This figure from the new research shows the 17 molecular clouds the researchers observed with ALMA. Most had the same filamentary shape as clouds in the Milky Way, shown in the yellow boxes. But 40% had a fluffy shape, as shown in the blue boxes. Image Credit: (ALMA (ESO/NAOJ/NRAO), Tokuda et al. 2025, ESA/Herschel)

In their paper, the authors describe it this way: “Our analysis shows that about 60% of the clouds have steep radial profiles from the spine of the elongated structures, while the remaining clouds have a smooth distribution and are characterized by lower brightness temperatures. We categorize the former as filaments and the latter as nonfilaments.”

This figure shows the 17 molecular clouds in the study. The ones with yellow check marks are the ones identified as filaments. Image Credit: Tokuda et al. 2025.

The clouds were not uniform and displayed a diversity of shapes. The researchers classified them into four separate types: single filaments, hub filaments, spatially compact clouds, and diffuse clouds.

These panels illustrate the four types of filaments the authors used to categorize their observations: (a) single filaments, (b) hub filaments, (c) spatially compact clouds, and (d) diffuse clouds. Image Credit: Tokuda et al. 2025.

The temperature difference between the filamentary and fluffy shapes was probably due to their ages. The authors think all clouds started out as filamentary and had high temperatures due to cloud-to-cloud collisions. The clouds have weak turbulence when the temperatures are higher.

However, as the temperature drops, the movement of the incoming gas creates more turbulence. This smooths out the filamentary structure, creating the fluffy shapes.

According to the research, filamentary and fluffy clouds form stars differently. Clouds that hold onto their filamentary shapes are more likely to break apart along their length and form many lower-mass stars similar to our Sun, including planetary systems. When the filamentary structure changes to a fluffy structure, it becomes more difficult for such stars to form.

The implication is that the morphology of the clouds tells us about their evolutionary stages.

“Some of the filamentary clouds are associated with YSOs with outflows and exhibit higher temperatures, likely reflecting their formation conditions, suggesting that these clouds are younger than the nonfilamentary ones,” the authors write in their paper.

The study also emphasizes that the same temperature and structure changes have not been observed in higher metallicity environments like the Milky Way. “Such transitions in structure and temperature have not been reported in metal-rich regions, highlighting a key behaviour for characterizing the evolution of the interstellar medium and star formation in low-metallicity environments,” the authors explain.

With these results, Tokuda says the next step will be to compare them with observations of the Milky Way and other environments richer in heavy elements.

“This study indicates that the environment, such as an adequate supply of heavy elements, is crucial for maintaining a filamentary structure and may play an important role in the formation of planetary systems,” said Tokuda. “In the future, it will be important to compare our results with observations of molecular clouds in heavy-element-rich environments, including the Milky Way galaxy. Such studies should provide new insights into the formation and temporal evolution of molecular clouds and the universe.”

There are still more details to uncover about these filaments, what shapes them, and how they affect the stars they form. How does turbulence play its role? What role do magnetic fields play? Some filaments host YSOs with protostellar outflows. How does that radiative feedback affect the filaments?

Future research will address those questions.

“Future studies using the James Webb Space Telescope to measure the detailed IMF <initial mass function> down to the low-mass regime, combined with ALMA’s ability to probe the physical properties of the parent molecular gas, will be crucial to deepening our understanding of star formation in low-metallicity environments,” the authors conclude.

• Press Release: In ancient stellar nurseries, some stars are born of fluffy clouds
• Research: ALMA 0.1 pc View of Molecular Clouds Associated with High-mass Protostellar Systems in the Small Magellanic Cloud: Are Low-metallicity Clouds Filamentary or Not?

The post Fluffy Molecular Clouds Formed Stars in the Early Universe appeared first on Universe Today.

Tasmanian devils are already being released inside predator-proof sanctuaries in New South Wales, and rewilding advocates believe they could suppress feral cats and foxes across the continent

A REMINDER

Yesterday I put up several posts about the binary nature of sex. On one of them I reported that several of us had signed a letter to the Presidents of three ecology/evolution societies who had issued a missive to Trump and all the members of Congress (I don’t think their missive has yet been sent). I wrote this:

Note that the Society for the Study of Evolution (SSE), the American Society of Naturalists (ASN), and the Society of Systematic Biologists issued a declaration addressed to President Trump and all the members of Congress (declaration also archived here), a statement deliberately aimed at contradicting the first Executive Order by declaring that sex is not binary but a spectrum—in all species!

A first version of our own letter, signed publicly by 20 people (there are now almost 40) can be read here.

If you want us to consider adding your name to our letter above—for we’re still accumulating signatures—please click on the link below, which is an early version of the letter with some signatures.

At the bottom of the letter, you will see this form:

If you want your name to be added to the letter that will be sent to the SSE, ASN, and SSB, please go to the site above and fill in the blanks. And all of them please, as people are leaving off titles, emails and sometimes last names. We’ll track down titles and the like, but that’s about all we can do to recover missing information.

The deadline for signing is a week from Monday: 5 p.m. Chicago time on March 3. 

We ask only two things: you be affiliated with biology in some way (training in biology sufficient to adjudicate the issues is sufficient), and that you be willing to have your name publicized, not only to the societies but on this website (I’m not sure if I’ll post the final version, though).  Your response will automatically be added to an Excel document from which we’ll draft the final letter. Your email address will always be kept confidential Thanks!

h/t to Luana Maroja for drafting the letter and collecting many of the signatures.

Papa’s got a brand new book, with Papa being NYT columnist Ross Douthat and his new book being Believe: Why Everyone Should Be Religious.  Douthat makes the familiar argument that it’s more rational to be religious than atheistic or agnostic, and pushes his own Catholicism as the “right” religion.  It’s bad enough that a NYT columnist is deluded in this way, but it’s worse when he proselytizes his faith all over the Internet, trying desperately to make people embrace Catholicism.

Excerpts of this book are everywhere, a form of self-plagiarism and self-aggrandizement that is especially prominent in the deeply pious. I’ve criticized Douthat and his book excerpts several times, but of course folks sufficiently desperate to find “the meaning of life” in religion—to fill their God-shaped hole—will make the book a best seller.  The excerpt for today was published in the Catholic journal The Lamp, (characterized by the newspaper The Catholic Spirit “the Catholic version of The New Yorker”), and you can read it for free by clicking on the headline. Here Douthat reveals the extent of his delusion: the things he thinks about Catholic dogma that are actually true.

An excerpt (it’s longer but I can’t bear to reproduce more than this). Bolding is mine:

But isn’t all this talking around an essential question, which is whether I think the tradition I’ve ended up practicing is actually true? Not just true enough, not just pointing toward God, not just generally accurate in its description of the nature of God or the cosmos, but also true in its most important claims about reality? After all, Catholics don’t just stand up on Sundays and proclaim their belief in monotheism, a diversity of supernatural beings, sacramental grace, and the goodness of creation. We profess belief in “one Lord Jesus Christ, the Only Begotten Son of God, born of the Father before all ages,” who came to earth and “by the Holy Spirit was incarnate of the Virgin Mary,” who died on the cross in Roman Palestine and “rose again on the third day in accordance with the scriptures,” who will eventually “come again in glory to judge the living and the dead.” And that is just the creedal condensation of a long list of specific claims about the way to salvation, the requirements of the moral law, the authority of the bishops and the pope—enough to fill a thick bound catechism, at the very least.

When I say the Nicene Creed, I mean it. I am open to hidden complexities and unexpected syntheses, but in the end I think that God has acted in history through Jesus of Nazareth in a way that differs from every other tradition and experience and revelation, and the Gospels should therefore exert a kind of general interpretative control over how we read all the other religious data. I think the New Testament is just clearly different from other religious texts in a way that stands out and demands attention, that the figure of Jesus likewise stands out among religious founders, that together the sources and the story and the Nazarene Himself all seem God-touched to a degree unmatched by any of their rivals. So where there is uncertainty, tension, a wager to be made, I make my bet on Jesus.

I’d put up $500 against the truths of the Nicene Creed, but of course Douthat has never written a single sentence I’ve seen telling us what would make him reject Catholicm. (In contrast, I laid out in Faith Versus Fact the kind of things that would make me provisionally accept the truths of Christianity.)

Okay, it’s time to look at the Nicene Creed, also discussed in my book.  Douthat’s claim that when he says it, he really means it is shared by many Catholics. That puts paid to the arguments of Sophisticated Theologians® that the Creed is either metaphorical or some soothing words to effect a bonding experience. Nope, that’s not why it was written. It was written so Christians could verbally profess the things they actually believe.

There are several versions of the Creed.  This one I took from the website of the United States Conference of Catholic Bishops, titled “What We Believe”. I was going to put in bold all the empirical things that Douthat accepts, but I would have had to put the whole thing in bold:

I believe in one God,
the Father almighty,
maker of heaven and earth,
of all things visible and invisible.

I believe in one Lord Jesus Christ,
the Only Begotten Son of God,
born of the Father before all ages.
God from God, Light from Light,
true God from true God,
begotten, not made, consubstantial with the Father;
through him all things were made.
For us men and for our salvation
he came down from heaven,
and by the Holy Spirit was incarnate of the Virgin Mary,
and became man.
For our sake he was crucified under Pontius Pilate,
he suffered death and was buried,
and rose again on the third day
in accordance with the Scriptures.
He ascended into heaven
and is seated at the right hand of the Father.
He will come again in glory
to judge the living and the dead
and his kingdom will have no end.

I believe in the Holy Spirit, the Lord, the giver of life,
who proceeds from the Father and the Son,
who with the Father and the Son is adored and glorified,
who has spoken through the prophets.

I believe in one, holy, catholic and apostolic Church.
I confess one Baptism for the forgiveness of sins
and I look forward to the resurrection of the dead
and the life of the world to come. Amen.

As you see, Douthat has dined on the whole hog from snout to tail: Jesus was the son of God (and himself God), was born of a virgin, was crucified as a way to save humanity, but then came back to life again and shortly thereafter ascended to Heaven.  He will return some day, although we’ve been waiting 2,000 years. That apparently doesn’t bother Douthat despite Jesus’s disproven claim that he would return while some of his contemporaries were still alive. And on that blessed day of Rapture, Jesus will judge everyone, sending them either up, down, or in the waiting room of Purgatory.

Douthat also accepts the Holy Spirit, whatever that is, and, of course, the forgiveness of sin and eternal afterlife.

This is what Douthat thinks is really true, and what he wants you to believe (see his book).  If he were the only person who professed this stuff, he’d be taken as a lunatic (see C. S. Lewis), but because the delusion is so widespread, it’s considered respectable.  But how can such a man not only be allowed to write for the NYT, but to actually publish this palaver in the newspaper?

Coming: the Good News about Xenu.

h/t: Barry

PLEASE send in your wildlife photos, ASAP!  Thank you.

Today we have a combination picture-and-text post by Athayde Tonhasca Júnior, and the subject is epitaphs.  Athayde’s comments are indented, and you can enlarge the photos by clicking on them.  The epitaphs are in italics:

The long dead speak to us – again

Most ancient Greek and Roman texts that helped shape Western culture were written by white men high up the social ladder (unsurprisingly, woke warriors are determined to defund, distort or do away with Classic studies). Epitaphs, on the other hand, give us glimpses of the lives of ordinary people of whom we know little: tradesmen, women, soldiers, gladiators, slaves. Some of these inscriptions are surprisingly familiar and poignant, considering how odd, cruel and violent the Ancients may seem to us.

A while back we looked at some Greek and Roman epitaphs; here’s another batch with their accompanying translations, where parentheses indicate missing and presumed words. Epigraphy, the study of inscriptions on stone, metal and other durable materials, is skilled detective work. Fading, truncations, misspellings, initialisms and abbreviations make interpretation difficult, even for Classics scholars. Comments are my own.

All objects depicted but the last one are housed in the unmissable Capitoline Museums in Rome.

Epitaph of Geminia Agathe Mater, 2nd c. AD. Tartarus mentioned in the last line was the place for the punishment of sinners after death. Not an appropriate destiny for a little girl, so the author must have been theologically confused:

For the souls departed. For the sweet Geminia Agathe Mater. My name was Mater, but I was never destined to become a mother. In fact I do not deny having lived only 5 years, 7 months and 22 days. During the time that I lived, I enjoyed myself and I was always loved by everyone. In fact, believe me, I had the face of a little boy, not of a girl; as only those who generated me knew Agathe, of gentle temperament, of pleasing and noble appearance, with red hair, short on top and long behind. Now all of (you) offer me nice drinks and pray that the earth does not weigh heavily upon my remains. Do not despair too much about the remains of my little (body), Faventius, who raised me more than my parents and who loved only me. In fact, I have a mother and a father who preceded me some time ago and never grieved over (my) destiny. I also have a sister by (my) mother Amoena, who is also saddened by my death. Please, everyone comforts my family, (reminding) them of the pleasant life (that I lived), reciting prayers so that (their) pain does not increase and their sadness does not exceed the limits. You who read, if you wish to know my whole name will know Geminia Agathe, whose premature death stole and brought at a tender age to Tartarus. This is all, more cannot happen: this (is foreseen) for us.

Epitaph of Menophilos, written in Greek, 2nd c. AD. Greek was spoken widely in Rome and the Western Empire, where it was considered a second language. Mentioning the muses, Bacchus and Aphrodite, suggests that Menophilos lived a hedonistic and gratifying life, albeit short:

While I passed my entire life in joy, smiling, playing and happy, and I delighted my soul with all kinds of pleasures in the art of song, never sorry, I never pronounced offensive words, but (was) a friend of the Muses, of Bacchus and of Aphrodite. I arrived from Asia to Italy, now I rest among the dead while still youthful. My name is Menophilos.

Epitaph of Ammias, from one of Rome’s Jewish catacombs. 3rd-4th c. AD. Text in Greek and some Semitic words. Rome had a significant Jewish population since 27 BC, after many of them fled the Hellenistic wars in today’s Turkey and the Middle East. Things started turning sour for the Jews in 313, when Constantine made Christianity the Empire’s legal religion:

Here lies Ammias, a Jew from Laodicea, who lived 85 years. In peace.

Funerary inscription of Ovia Quarta, 2nd c. AD. The two figures flanking the tablet are laruae (sing. larua), wandering spirits of the dead. A larua was also the mask worn by a performer in the role of such ghost. With time, the Latin ‘u’ morphed into ‘v’, so larua became larva. Linnaeus, who knew Latin and the Classics like any other contemporary naturalist worth his salt, adopted ‘larva’ to define the life stage of an insect hidden behind the ‘mask’ of immaturity to be removed and reveal the adult’s appearance. The laruae were also known as lemures, another term snatched by Linnaeus to describe those eerie and secretive Malagasy primates:

Ovia Quarta lived 60 years.

Funerary table of Alexander, 2nd c. AD. The DM initialism in the first line of text refers to dis manibus, translated as ‘for the souls departed’, ‘to the memory of’ or ‘to the spirits of the dead’, and is a conventional inscription commonly found on Roman tombstones. The last four letters, STTL, are also formulaic. They stand for sit tibi terra levis: ‘may the earth be light on you’. When Christians began replacing pagan nonsense with their own, STTL was swapped for RIP (requiescat in pace), which conveniently works in English:

For the souls departed. Alexander lived 3 years, 4 months and 19 days. His father, Quintus Canuleius Alexander, and his mother, Clarina, saw to (the making of this tomb) for their dear, devoted and well-deserving son. He is buried here. I beg you, when you pass (nearby), to say: may the earth be light upon your remains.

The humble funerary inscription of a head teacher, 1st c. AD:

To Lucius Sentius Index, head of tutors. He is buried here.

Funerary altar of freedman Tiberius Julius Xanthus, 1st c. AD. Freedmen in Rome could become citizens and climb high on the social ladder, amass money, buy property and own their own slaves. Tiberius the VIP masseur could have done worse, as suggested by the fancy altar dedicated to him. Certainly he seemed to have done better than the head teacher, who was left with a modest plaque. Some things never change. . . :

To the imperial freedman Tiberius Julius Xanthus, masseur of the emperors Tiberius Caesar and the Divine Claudius and vice-commander of the Alexandrian navy, dedicated by his wife Atellia Prisca and the freedman Lamyrus, his heirs; he lived 90 years.

Funerary inscription celebrating Crescens the charioteer, 2nd c. AD. The Olympic Games, FIFA World Cup and the Superbowl pale when compared to the popularity and social reach of chariot racing in Greece, Rome and Byzantium. Fortunes could be made and lost in bets, and racing events often degenerated into violence and riots. Owners of champion horses could become famous and rich, but drivers and horses often didn’t see the end of a race, being maimed or killed by collisions and crashes – which were some of the main attractions for the hoi polloi. Drivers could race alone or for the Blue, Green, Red or White teams. For an excellent take on Roman chariot racing, see Asterix and the Cauldron:

Crescens, charioteer of the blue faction, originally from Mauritania, 22 years old. He achieved his first victory with a quadriga in the 24th race (staged) when L(ucius) Vipstanus Messalla held the consulship, on the anniversary of the birth of the divine Nerva, with these horses: Circius, Acceptor, Delicatus and Cotynus. Between the consulship of Messalla and that of Marcus Acilius Glabrio, on the anniversary of the birth of the divine Claudius, Crescens raced 686 times. He won 47 competitions: 19 with one chariot, 23 with two chariots and 5 with three chariots; in one race he won thanks to his teammates; in 8 he was in the lead from the start, and from the last position he won 38. He came in second place 130 times; third place 111 times; he won 1,558,346 sesterces.

Inscription on the tomb of Caius Novius Mynias, 2nd c. AD. Caius must have been an unsentimental, no-nonsense chap, considering the information he chose to leave for posterity. But he shared a recurrent concern among people burying their dead: the defacing, theft or destruction of monuments. To prevent such affrontery, amulets, curses and magic spells were frequently attached to tombs, altars and crypts:

For the souls departed. Caius Novius Mynias saw to (the making of this tomb) for himself, his freedmen, freedwomen, for his and their descendants. To this funerary monument belongs a garden with an edifice, bordered by a wall, extending 280 feet along the front and 360 feet towards the countryside; these (structures) belong to the freedmen and freedwomen of Novius Mynias, those who are and who will be, and to whoever is born of them; to the same garden and edifice belongs a pathway through the main entrance of the gardens or the fundus Meropianus. May trickery and fraud stay away from this funerary monument.

Funerary altar of a humble poet, 2nd c. AD.:

For the souls departed. Here I lie, Claudius Diadumenus, poet by trade, once rich with imperial commissions, who was never possessed by the love for fame, but always maintained a modest way (of life). O Hyllus, o father, I have joined you. I do not wish to create a commotion: for us, this house is a hospitable place. Claudia Fructiane made this to the well-deserving (Diadumenus).

And finally, a coarse and facetious take on funereal epitaphs on a graffito scribbled on a Pompeii wall. The text, in cursive Latin and following a pentameter rhyme, warns those feeling the urge to squat behind a tomb about the dangers of stinging nettle (urtica). It reads:

Hospes adhuc tumuli ni meias ossa prec[antur],

nam si uis (h)uic gratior esse caca.

Urticae monumenta vides discede cacator

non est hic tutum culu(m) aperire tibi.

Stranger, my bones beg you not to pee at my tomb: if you wish to be more pleasing to the deceased, shit. You look upon the monuments of stinging nettle: go away, shitter. It is not safe for you to open your arse here.

Let’s dive into one of those cosmic curiosities that’s bound to blow your mind: how we might chat with aliens. And no, I’m not talking about elaborate coded messages or flashy signals. We’re talking about something incredibly fundamental—21cm radiation.

If you’re planning on having a conversation across the vastness of space, using light waves (electromagnetic radiation) is pretty much your go-to option. It’s fast, reliable, and, well, it’s the most practical way to shout out to other civilizations in the universe. But why specifically 21 centimeters? That’s where things get juicy.

This 21cm radiation isn’t just some random frequency we picked out of a hat. It’s tied to something very essential, known as the hydrogen spin flip. Hydrogen atoms consist of one proton and one electron, and these tiny particles have a property called “spin.” Think of spin like a little arrow pointing up or down. Every so often, in the vast reaches of space, a hydrogen atom’s electron can flip its spin, going from a state where its spin is aligned with the proton to one pointing in the opposite direction. This flip releases energy in the form of radiation at—you guessed it—a wavelength of 21 centimeters.

So, why does this matter? Well, any smart civilization, whether they have blue skin, tentacles, or something more bizarre, will eventually discover hydrogen, understand spin, dabble in quantum mechanics, and figure out this whole 21cm radiation thing. They’ll call it something different (they won’t have “21” or “cm”) but the concept remains universal. It’s like the cosmic Rosetta Stone.

What makes 21cm radiation perfect for long-distance interstellar chats is its ability to cut through interstellar dust. Space is filthy, with dust clouds that block out other forms of light. However, 21cm waves are like the VIPs of the universe, slipping through the velvet ropes of cosmic debris to carry their message far and wide.

Here’s a fun fact: NASA’s Pioneer spacecraft, launched in the early 1970’s, carry plaques. On these plaques there’s a handy diagram of the hydrogen spin flip transition. All other measurements on the plaque, including the height of humans, are made in reference to this fundamental distance. So the hope is that aliens can recognize the hydrogen spin-flip transition and use that to unlock the rest of our message.

Now imagine this scenario: One day, astronomers on Earth detect an unusual surge of 21cm radiation. It’s not coming from a random hydrogen cloud; it’s directional, purposeful. That could very well be an alien civilization sending us a “What’s up?” across the cosmos – 21cm radiation makes for a great calling card.

Using 21cm radiation to communicate with extraterrestrial beings leverages a basic, universal constant. And who knows? Maybe one day, when we finally hear that signal, we’ll know that somewhere out there, another intelligent species figured out the same galactic hack we did.

So keep your eyes—or rather, your telescopes—peeled. The next big discovery could be just a spin flip away!

The post If You’re Going to Call Aliens, Use This Number appeared first on Universe Today.

The majority of the universe remains unmapped, but we have a potential window into it through a peculiar light emitted by nothing other than neutral hydrogen.

Before stars and galaxies lit up the universe, the cosmos was a dark place filled mostly with neutral hydrogen. This was right after the Big Bang and the formation of the CMB—Cosmic Microwave Background. The CMB is like a baby picture of the universe when it was just 380,000 years old. But what came next was a long period called the “Dark Ages.” During this time, the universe didn’t have much going on in terms of visible light because there were no stars or galaxies yet. Frustratingly, most of the volume of the visible universe exists in these Dark Ages, which makes it a very valuable resource to learn about the nature of dark matter and dark energy. But…it was dark, so we can’t just make a bigger telescope and observe it.

Thankfully, the neutral hydrogen that filled the universe during this epoch does emit a feeble kind of light. Due to the quantum mechanical spin flip transition, neutral hydrogen emits radiations with a wavelength of 21 centimeters. However, the Dark Ages were so long ago at this 21cm radiation is redshifted to a wavelength of two meters or more, putting it firmly in the radio band of the electromagnetic spectrum.

In fact, a tiny fraction of the static you hear in your car radio is due to this ancient radiation.

Astronomers can use slightly different wavelengths to map out the extent and evolution of the Dark Ages. Different pockets of neutral gas will emit their radiation at different times, which will correspond to different redshifts.

We expect to see an enormous amount of 21cm radiation at the very longest wavelengths, right at the beginning of the Dark Ages. That’s when the universe was filled with an almost uniform distribution of neutral hydrogen. Then as the first stars and galaxies wake up, they ionize their surrounding gas with powerful blasts of high-energy radiation. So a 21cm map of this era should show holes and pockets in the overall signal. Finally, once most of the neutral hydrogen is wiped away and confined only to cool regions of galaxies, we should see the signal disappear – only to be replaced with the light of galaxies themselves.

However, observing this radiation is a daunting task. That’s because humans are also quite fond of radio emissions, and this signal from the Dark Ages is at least a million times weaker than terrestrial radio broadcasts. Observatories around the world, like the Murchison Wide-field Array in Western Australia and the Hydrogen Epoch of Reionization Array in South Africa have so far failed to find a conclusive signal.

To nail this detection and open up the Dark Ages to exploration, we may have to go off planet. The Lunar Crater Radio Telescope hopes to turn the far side of the Moon into a pristine radio observatory, using the Moon itself to shield the observatory from radio interference. The idea is a long way off, but it might be our only way to to draw a complete map of the cosmos’ past, present, and future.

The post Neutral Hydrogen: The Next Big Game in Cosmology appeared first on Universe Today.

Yesterday I posted an animation of a quantum wave function, and as a brain teaser, I asked readers to see if they could interpret it. Here it is again:

Yesterday’s wave function, showing an interesting interference phenomenon.

Admittedly, it’s a classic trap — one I use as a teaching tool in every quantum physics class. The wave function definitely looks, intuitively, as though two particles are colliding. But no. . . the wave function describes only one particle.

And what is this particle doing? It’s actually in the midst of a disguised version of the famous double slit experiment! This version is much simpler than the usual one, and will be super-useful to us going forward. It will make it significantly easier to see how all the puzzles of the double-slit experiment play out, both from the old, outdated but better known perspective of 1920’s quantum physics and from the modern perspective of quantum field theory.

You can read the details about this wave function — why it can’t possibly describe two particles, why it shows interference despite there being only one particle, and why it gives us a simpler version of the double-slit experiment — in an addendum to yesterday’s post.

Physicists use mathematical assumptions in many situations that forbid time from moving backwards – but that isn’t necessarily a reflection of quantum reality

I am fascinated by the technologies that live largely behind the scenes. These are not generally consumer devices, but they may be components of consumer products, or may largely have a role in industry – but they make our modern world possible, or make it much better. In addition I think that material science is largely underrated in terms of popular appeal, but it is material science that often make all other technologies possible or feasible. There is another aspect of technology that I have been increasingly interested in – solid state technology. These are, generally speaking, devices that use electricity rather than moving parts. You are likely familiar with solid state drives, that do not have spinning discs and therefore are smaller, use less power, and last longer. One big advantage of electric vehicles is that they are largely solid state, without the moving parts of an engine.

There is a technology that combines all three of these features – it is a component technology, dependent on material science, and solid state: thermoelectric devices. This may not sound sexy, but bear with me, this is cool (pun intended) technology. Thermoelectric materials are those that convert electricity into a temperature difference across a material, or convert a temperature difference into electricity. In reality, everything is a thermoelectric material, but most materials have insignificant thermoelectric effects (so are functionally not thermoelectric).

Thermoelectric devices can be used to harvest energy, from any temperature difference. These are generally not large amounts of energy – we don’t have thermoelectric power plants connected to the grid – and they are currently not practical and cost effective enough for a large scale. This may be possible in the future, but not today. However, for applications that require small amounts of energy, harvesting that energy from ambient sources like small temperature differences is feasible.

There are likely many more applications for the reverse – using electricity to cause temperature changes. This is basically a refrigerator, and in fact y0u can buy small solid state thermoelectric refrigerators. A traditional refrigerator uses a compressor and a refrigerant. This is a liquid that turns into a gas at low temperature, absorbing heat when it transitions to gas and then letting off heat when it transitions back to liquid. But this requires a compressor with moving parts and pipes to carry the refrigerant. Refrigerants are also not good for the environment or the ozone. Thermoelectric coolers can be smaller, use less electricity, are quiet, and have more precise temperature control. But their size is limited because they are not powerful enough for full-sized refrigerators.

As an aside, I see that Samsung is coming out this year with a hybrid full-size refrigerator. I still uses a compressor, but also has a thermoelectric cooler to reduce temperature variation throughout the refrigerator.

Thermoelectric cooling is also useful for electronics, which having an increasing problem with heat dissipation as we make them smaller, more compact, and more powerful. Heat management is now a major limiting factor for high end computer chips. This is also a major limiting factor for bio-electronics – implanting chips in people for various potential applications. Having a small and efficient solid state cooling device that just requires electricity would enable this technology.

But – the current state of the art for thermoelectric cooling is limited. Devices have low overall efficiency, and their manufacture is expensive and generates a lot of waste.  In other words – there is a huge opportunity to improve this technology with massive and far ranging potential benefits. This is an area ripe for investment with clear benefits. This can also be a significant component of our current overall goal to electrify our technology – to accomplish with electricity what currently requires moving parts and fossil fuels.

All this is why I was very interested in this latest advance – Interfacial bonding enhances thermoelectric cooling in 3D-printed materials. This incorporates yet another technology that has my interest – 3D printing, or additive manufacturing. This does not represent an improvement in the thermoelectric devices themselves, but an improvement in the cost and efficiency of making them (again, and often neglected by very important aspect of any technology). As one of the authors says:

“With our present work, we can 3D print exactly the needed shape of thermoelectric materials. In addition, the resulting devices exhibit a net cooling effect of 50 degrees in the air. This means that our 3D-printed materials perform similarly to ones that are significantly more expensive to manufacture,” says Xu.”

The innovation has to do with the molecular bonding of the materials in the 3D printing process. As Xu says, the performance is the same as existing materials, but with much lower cost to manufacture. As always, shifting to a new technology often means that there is room for further incremental advances to make the advantages even better over time. It may take years for this technology to translate to the market, but it is very possible it may lead directly to a slew of new products and applications.

It may seem like a small thing, but I am looking forward to a future (hopefully not too distant) with full-sized thermoelectric refrigerators, and with computers that don’t need fans or water cooling. Having a silent computer without fans is nice for podcasting, which I know is a particular interest of mine, but is also increasingly common.

In general, quality of life will be better if we are surrounded by technology that is silent, small, efficient, cost-effective, and long-lasting. Thermoelectric cooling can make all of that increasingly possible.

The post Thermoelectric Cooling – It’s Cooler Than You Think first appeared on NeuroLogica Blog.

By fusing different human organoids, researchers have created “mini-brains” containing most of the cell types found in fetal brains

New observations have dramatically reduced the chances of asteroid 2024 YR4 hitting Earth in 2032, lowering the risk to minimal levels, but its extraordinarily close approach will offer astronomers the chance to examine it in detail

A new AI-based method can accurately recover digital data from DNA strands nearly 90 times faster than older techniques, raising the possibility of practical DNA storage for computing