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When MSL Curiosity was sent to Gale Crater, one of its goals was to study boxwork ridge features on Mt. Sharp. The rover has gathered its fourth sample from the rocks, and results are on their way. Previous samples showed tantalizing evidence in favour of ancient life on Mars. But we're still waiting for the extraordinary evidence required to conclude that Mars was once inhabited.

Astronomers have long debated why so many icy objects in the outer solar system look like snowmen. Michigan State University researchers now have evidence of the surprisingly simple process that could be responsible for their creation. Jackson Barnes, an MSU graduate student, has created the first simulation that reproduces the two-lobed shape naturally with gravitational collapse. His work is published in the Monthly Notices of the Royal Astronomical Society.

Area 51 may want to dust off the welcome mat. Not one, not two, but three interstellar objects have drifted through our solar system, now referred to as “interstellar interlopers.” Astronomers labeled them as 1I/‘Oumuamua in 2017, 2I/Borisov in 2019, and 3I/Atlas in 2025 (the prefixes refer to the order of discovery of the interlopers). While most astronomers see unusual but ultimately natural cosmic debris, Harvard astronomer and Galileo Project head Avi Loeb has stepped up to suggest these anomalous interstellar visitors could be alien technologies, possibly even a threat to humanity. Before we start waving white flags at space rubble, it’s worth noting that the rest of the scientific community is responding with something far less dramatic: data. Most scientists, armed with models and common sense, see nothing more exotic than fast-moving rocks and comets with unusual chemical compositions.

Avi Loeb: Prophet, Seer, or Publicity Seeker? 

Avi Loeb is no UFOlogist conspiracy theorist with an active imagination. He holds Harvard’s Frank B. Baird Jr. Professorship of Science and has spent most of his academic life developing rigorous theories about black holes, galaxy formation, and the early universe. So, when he started speculating about alien artifacts drifting through our solar system and writing several popular books about extraterrestrials, it’s no surprise that a bevy of UFOlogists treated his words as something akin to the “next coming.” 

In recent years, he has become known less for his contributions to cosmology and more for a far more audacious proposition: that humanity may have already encountered extraterrestrial technology created somewhere beyond our solar system. The shift has turned him into a public figure with an unusually large following for an astrophysicist, even as it strains his standing among colleagues. Admirers see him as refreshingly fearless and he has inspired my young students to go into the sciences (he regularly posts emails from them on his Medium blog); critics describe him as a man who has allowed publicity to eclipse prudence. The tension between those two views defines the controversy that now surrounds his work. 

The ‘Oumuamua Puzzle and Loeb’s Radical Interpretation 

When astronomers in Hawaii identified an unfamiliar object sweeping through the solar system in October 2017, they immediately realized it was something unprecedented. The object—later named ‘Oumuamua (Hawaiian for “messenger from afar”)—did not behave like the comets or asteroids astronomers routinely study. Its elongated appearance, lack of visible outgassing, and slight but measurable change in velocity puzzled researchers. 

A large team of scientists, led by Karen Meech at the Institute for Astronomy in Hawaii, published a widely cited paper in Nature in 2017, concluding that ‘Oumuamua originated from outside our solar system. Building on the data from that paper, Avi Loeb and his graduate student Shmuel Bialy (now at the Israel Institute of Technology) proposed in a 2018 Astrophysical Journal Letters paper that ‘Oumuamua might be a “fully operational probe sent intentionally to Earth vicinity by an alien civilization.” That is, of course, a possibility—as is a cosmic teapot in orbit. But science does not require disproving every far-fetched alternative. The burden of proof lies squarely with Loeb and his collaborators. 

In his boldly titled book Extraterrestrial: The First Sign of Intelligent Life Beyond Earth, Loeb offered a hypothesis that captured worldwide attention: perhaps ‘Oumuamua was not a natural relic at all but rather a fragment of engineered technology, possibly a thin, reflective structure propelled by starlight. He emphasized that he wasn’t announcing definitive proof (despite the book’s title), only pointing out that an artificial origin could not be ruled out. Nonetheless, his willingness to discuss this prospect publicly pushed the story far beyond the walls of academia. 

Here are a few unique characteristics of ‘Oumuamua: 

1. ‘Oumuamua’s light curve. A light curve is a graph that shows how the brightness of an object changes over time. In 2019, Sergey Mashchenko analyzed the light curve from ‘Oumuamua, concluding that “the most likely model for ‘Oumuamua is a thin disc (slab) experiencing moderate torque from outgassing.” ‘Oumuamua’s brightness varied dramatically because it tumbled, suggesting an extreme aspect ratio (possibly 5:1 or more). That implies it was either very elongated like a cigar or very flat like a pancake. The shape is unlike anything in our solar system, and “non-comet-like.” 
2. ‘Oumuamua’s acceleration. Astronomers observed ‘Oumuamua making a nongravitational acceleration, that is, it sped up slightly as it left the Sun’s gravity well. 
3. ‘Oumuamua lacks a “comet” tail. Typically, comets coming in from the outer reaches of the Kuiper Belt or from within the Oort Cloud surrounding our solar system contain ice gases. Comets can develop two main types of tails. An ion (or plasma) tail forms when the solar wind—a stream of charged particles flowing outward from the Sun—interacts with gases from the comet. The solar wind ionizes these gases by stripping away electrons, and the resulting charged ions are then swept directly away from the Sun by the magnetic field carried in the solar wind. This produces a straight, narrow, bluish tail that always points directly away from the Sun, no matter which way the comet is moving. A dust tail, in contrast, is created when sunlight exerts radiation pressure on tiny dust particles released from the comet’s nucleus, pushing them away from the Sun. Because these dust particles follow slightly different orbits from the comet itself, the dust tail is broader, curved, and usually whitish or yellowish; it lags slightly behind and follows the curve of the comet’s trajectory around the Sun. 
4. ‘Oumuamua reflected more sunlight than typical asteroids or comets. 
5. ‘Oumuamua’s velocity entering the solar system was similar to the average speed of stars in the Sun’s neighborhood. Loeb pointed out that this was unusual and “unlikely by chance.” 

Occam’s razor, named after William of Ockham (1287–1347) by Libert Froidmont (1587–1653), suggests that scientific hypotheses should consist of the smallest set of possible elements. For example, while staying in an old English hotel room, the lights flicker, the floor creaks, and the room gets chilly. You could conclude it’s the ghost of a Victorian child with unresolved issues—or, per Occam’s razor, you could check the wiring, the floorboards, and maybe close a window. When in doubt, blame the insulation before the afterlife. Occam’s razor doesn’t prove the simpler explanation is correct—just that it’s preferable until better evidence arises. It’s a tool for model selection, not an avenue to absolute truth. 

Admirers see Avi Loeb as refreshingly fearless and he has inspired my young students to go into the sciences; critics describe him as a man who has allowed publicity to eclipse prudence.

Let’s examine the data for ‘Oumuamua in this light. The elongated or flat shape: In three research papers, Steven Desch and Alan Jackson proposed that ‘Oumuamua is a collisional fragment of nitrogen ice from an exoplanetary Pluto-like body. Not only does this explain the flat shape, but the lack of observable H2O, CO, CO2, lack of dust, and especially the magnitude of the nongravitational acceleration. I asked Desch what he thought of Loeb’s ideas about ‘Oumuamua and he responded: “Suffice it to say he [Loeb] long ago stopped being a serious scientist making innocent inquiries, and now unstoppingly manufactures doubt in the service of positioning himself as some sort of science maverick.” Sebastian Lorek’s and Anders Johansen’s theoretical work demonstrates that flattened, disc-shaped planetesimals can form naturally through the gentle gravitational collapse of a rotating “pebble cloud” in a protoplanetary disk. Lorek and Johansen emphasized to me that “the formation of flattened objects like ‘Oumuamua is a completely natural outcome of planetesimal formation.” 

By contrast, Loeb postulates that ‘Oumuamua may be a light-sail—a thin, flat structure propelled by radiation pressure (i.e., the momentum of photons from starlight or sunlight). Photons carry no mass, but they do have momentum. When they hit a surface (especially a reflective one), they impart a tiny push. Over time, this small force accumulates, especially in the vacuum of space where there’s no friction. The challenge with using solar radiation for propulsion is that its force decreases with the square of the distance from the source (1/r²). While this pressure is weak but usable near Earth’s orbit (1 AU), it becomes vanishingly small at interstellar distances. In the vast space between stars, the photon flux is so low that even the nearest stars provide no meaningful thrust—effectively leaving a light sail adrift with nothing to push it along. 

AI-generated rendering of a hypothetical alien light sail, the type of technology Avi Loeb proposes could explain ‘Oumuamua’s unusual acceleration through solar radiation pressure.

As for the nongravitational acceleration of ‘Oumuamua out of our solar system, Loeb believes that it can’t be explained by outgassing, because no gas or dust was detected. He proposed that the acceleration was caused by the solar radiation pressure hitting a light sail. If ‘Oumuamua were an ultra-thin object, just 0.3–0.9 mm thick and tens of meters wide, it could have experienced enough radiation pressure at its closest approach to the Sun, which was 0.25 AU, or one-quarter of an Astronomical Unit (the distance from the Earth to the Sun, 1 AU) to account for the motion—without requiring any expelled material. However, in 2023, Jennifer Bergner and Darryl Seligman showed that entrapped molecular hydrogen (H2) in water ice could have been released from ‘Oumuamua’s body as it warmed, producing the observed nongravitational acceleration without a visible coma (the cloud of gas and dust that typically forms around a comet when it gets close to the Sun). This supports the view that ‘Oumuamua was a comet-like planetesimal rather than anything technological. Although the study centered on chemistry, a consequence is that ‘Oumuamua must have had a very high surface-area-to-mass ratio for H2 outgassing to be effective. Such a requirement is naturally met by a thin, sheet-like geometry (a flattened body), again consistent with the disc-like shape inferred by the light-curve analyses. In short, even its puzzling acceleration can be explained by natural processes acting on an unusually flat, icy object. 

The Galileo Project and Loeb’s Expanding Quest 

Rather than retreat from public engagement after ‘Oumuamua’s exit from the scene, Loeb broadened his search. In 2021, he launched the Galileo Project—funded entirely through private donations—with the goal of systematically looking for physical evidence of extraterrestrial technology. The initiative includes specialized camera systems aimed at tracking unusual aerial phenomena and an expanded effort to locate interstellar debris. 

One object in particular drew Loeb’s attention: a meteor that exploded over the Pacific Ocean in 2014. A U.S. Space Command memo suggested the meteor may have originated outside the solar system. Loeb seized upon the idea that remnants from this event might still rest on the ocean floor, potentially offering clues about materials forged beyond our stellar neighborhood. So in 2023 he orchestrated an expedition off the coast of Papua New Guinea to retrieve microscopic debris from the area where the meteor had disintegrated. Funded by a cryptocurrency entrepreneur, the mission blended scientific ambition with adventure-story drama—all captured by a documentary crew (to be aired in 2026). 

The expedition recovered tiny metal beads—mere fractions of a millimeter in diameter. Laboratory analyses revealed unusual ratios of heavy elements that did not neatly align with common terrestrial or meteoritic compositions. Loeb interpreted the findings as suggestive of an exotic, possibly interstellar, origin. He stopped short of outright claiming discovery of alien technology (the tiny spherules were not exactly the dashboard of the Millennium Falcon), but he made clear that he considered the possibility worth exploring. 

Many experts quickly objected. Planetary scientists noted that it is extremely unlikely for an object traveling at such high velocity to leave behind intact solid fragments. Others questioned whether the spherules could even be tied to the 2014 meteor, or whether the meteor itself was truly interstellar. Critics argued that uncertainties in the military data make firm conclusions impossible, and that Loeb was again presenting the most sensational interpretation well before the evidence justified it. 

The interstellar comet 2I/Borisov streaks through our solar system in this 2019 image from ESO’s Very Large Telescope. Unlike ‘Oumuamua, Borisov behaved like a typical comet, showing a bright coma and tail. The telescope tracked the comet’s movement, causing the background stars to appear as colorful streaks of light—a result of combining observations in different wavelength bands that give the image some disco flair. Credit: ESO/O. HainautThe interstellar comet 2I/Borisov behaves like a typical comet. 

2I/Borisov is considered interstellar because it entered the solar system on a hyperbolic trajectory—with an orbital eccentricity greater than 3—meaning it is not gravitationally bound to the Sun and must have originated from outside our solar system. Its inbound velocity (approximately 32 km/s) and trajectory indicate it came from the direction of the galactic plane, rather than from within the Oort Cloud or Kuiper Belt. Unlike ‘Oumuamua, which baffled astronomers with its lack of cometary features, Borisov behaved exactly like a typical comet, complete with a bright coma, a dust tail, and outgassing of familiar volatiles like water, carbon monoxide, and cyanide. 

Avi Loeb has suggested that Borisov may still deserve scrutiny as a potential technological relic—noting that it was more pristine than expected for a comet traveling interstellar distances, possibly implying unusual origins. However, most scientists interpret Borisov as strong evidence that other planetary systems form comets much like our own does. Its ordinary composition, active sublimation, and typical behavior all suggest it is natural, and in fact, it reinforces the view that cometary bodies are common ejecta from planetary systems throughout the galaxy. In Galileo Project Zoom meetings of late, Loeb has conceded that 2I/Borisov is a comet (Skeptic magazine’s Michael Shermer is on the Galileo Project team and attends the Zoom meetings). 

3I/Atlas: The Third Interloper 

3I/Atlas’s inbound excess velocity was about 58–61 km/s, far above the escape velocity of the Sun, indicating an origin outside the solar system (that is, it is not gravitationally bound to our solar system). Astronomers traced its incoming direction to the constellation Sagittarius and predict it will depart toward Gemini. Unlike the enigmatic ‘Oumuamua (which showed no outgassing) and more like 2I/Borisov, 3I/Atlas immediately revealed a coma and dust activity, behaving in most respects like a typical comet. Its trajectory and motion suggest it may have originated from the Milky Way’s thick disk, making it plausibly older than our solar system. 

Hubble’s image of interstellar comet 3I/ATLAS (365 million kilometers from Earth, July 21, 2025) shows a bluish, teardrop cocoon against streaked stars. While Avi Loeb suggests its sunward jet may be artificial, the consensus confirms it behaves like a natural comet. Credit: NASA, ESA, D. Jewitt (UCLA); Image Processing: J. DePasquale (STScI)

From the start, astronomers have viewed 3I/Atlas as a natural cometary body. Observatories around the world (including Hubble, the James Webb Telescope, and the Very Large Telescope in Chile) tracked its movement, noting that it started releasing gas and dust at large distances from the Sun—an unusual but not unprecedented behavior. Spectral studies revealed a coma rich in CO2, CO, and diatomic carbon (C2), while surprisingly low in water vapor, which typically dominates solar system comet outgassing. Polarimetry also showed an unusually strong negative polarization signal—meaning the light scattering off the coma’s dust was more directionally polarized than expected. (Polarimetry is the study of how light becomes polarized after it reflects off or scatters through materials like dust or gas. In astronomy, it’s used to analyze light from objects such as comets to infer the properties of their surfaces or comae. When astronomers applied polarimetry to 3I/Atlas, they found unusually strong negative polarization, suggesting its dust grains are very fine or have unusual textures—possibly hinting at a unique interstellar origin or formation environment.) These characteristics, while distinct, are seen as falling within the natural diversity of cometary compositions, especially for bodies formed in ultra-cold outer regions of a planetary system. 

Researchers note that 3I/Atlas offers a unique opportunity to expand our understanding of planetary formation beyond the solar system. Its high CO2 content, early activity, and evolving tail structure suggest it likely formed in a cold, distant part of its home system—perhaps analogous to our Kuiper Belt around a distant solar system. Its compact nucleus (likely under 1 km in size) and slowly rotating, modestly active profile, contrast with the wildly tumbling, inert ‘Oumuamua. Scientists have emphasized that 3I/Atlas aligns with the expected behavior of a comet ejected from another stellar system, and they see no need to invoke exotic explanations. 

Nevertheless, Avi Loeb has once again challenged the consensus. In public commentary and academic preprints, Loeb has listed a set of anomalies that, in his view, warrant consideration that 3I/Atlas might be artificial in origin. Among the features he highlights: 

• The comet’s entry angle aligns closely with the solar system’s ecliptic plane, a statistically unlikely coincidence, he argues. 
• Its antisolar jet initially pointed toward the Sun, rather than away, which Loeb suggests could imply directed propulsion rather than random outgassing. 
• Its mass-to-acceleration ratio seems extreme given its apparent size. 
• Spectral data show a high nickel-to-iron ratio in the coma, which Loeb suggests hints at industrial production instead of natural construction. 
• 3I/Atlas’s inbound direction is near that of the so-called “Wow!” signal, a fact Loeb labels “curious” rather than conclusive. The Wow! signal was a strong, unexplained radio burst detected in 1977 near the hydrogen frequency—a band considered promising for interstellar communication. It lasted 72 seconds, came from the direction of Sagittarius, and has never been observed again, making it an intriguing mystery in the search for extraterrestrial intelligence. 

Although intriguing, there is nothing alien about the 3I/Atlas’s jets. The presence of multiple jets pointing in both sunward and antisunward directions suggests that 3I/Atlas has several active regions on its rotating nucleus. As different surface areas are exposed to sunlight, localized jets of gas and dust are released, sometimes curving due to the object’s motion or erupting from regions not directly facing the Sun. This directional variety is a hallmark of cometary activity and reflects a complex interplay between surface composition, thermal dynamics, and rotational orientation, a more likely explanation than alien technology rocket thrusts and maneuvers that Loeb proposes. 

Both features fall within known cometary behavior and don’t require invoking alien technology.

The same can be said for other characteristics Loeb deems of alien origin. The high acceleration relative to 3I/Atlas’s apparent size can be explained naturally by low-density, volatile-rich materials like CO2 or CO ices producing sustained outgassing. Similarly, the elevated nickel-to-iron ratio in its coma may result from observational bias—nickel is more easily detected in cometary gas, while iron often remains locked in dust. Both features fall within known cometary behavior and don’t require invoking alien technology. 

Loeb’s position, as with ‘Oumuamua, is that extraordinary anomalies merit open-minded hypotheses. He does not claim that 3I/Atlas is definitively artificial, but argues that its distinctive properties should not be dismissed. He has proposed that it could represent alien debris, a probe, or some unknown technological object using controlled outgassing or exotic materials. Critics in the scientific community largely disagree, emphasizing that all of 3I/Atlas’s features—from its CO2-rich chemistry to its sunward jet and trajectory—can be explained by known physics. Observations of other comets with similar jets or compositional profiles provide natural precedents. 

While most planetary scientists remain confident in a natural origin for 3I/Atlas, its detailed study is ongoing. Loeb’s speculations, while provocative, remain unsubstantiated.

In late 2025, NASA officials released detailed observations of 3I/Atlas, and their conclusion was unequivocal: “It looks and behaves like a comet, and all evidence points to it being a comet. But this one came from outside the solar system, which makes it fascinating,” said NASA Associate Administrator Amit Kshatriya. Indeed, high-resolution images from spacecraft showed 3I/Atlas with a normal cometary coma and tail—essentially indistinguishable from ordinary long-period comets aside from its hyperbolic orbit. In other words, 3I/Atlas is far more likely a natural interstellar comet than an extraterrestrial spacecraft. 

In the end, 3I/Atlas has reinforced a key message: interstellar objects are not all alike, and some may appear quite strange by our standards. While most planetary scientists remain confident in a natural origin for 3I/Atlas, its detailed study is ongoing. Loeb’s speculations, while provocative, remain unsubstantiated. Whether the anomalies he flags prove to be outliers or just unfamiliar variations within a broad population of extrasolar comets, 3I/Atlas has already deepened our understanding of how planetary systems beyond our own may evolve—and what fragments they might fling into the void. 

A Netflix documentary crew has followed Loeb’s work for several years, including his 2023 expedition to recover interstellar meteor fragments from the Pacific Ocean. The film, which Loeb has confirmed is in production, is expected to be released in 2026 and will chronicle his search for extraterrestrial technology. It reflects not only his scientific ambitions but also his increasingly prominent role in the public imagination.

The environmental impact of SpaceX's planned gargantuan mega-constellation is still being grappled with, but the FCC isn’t required to study it

Many of us obsess over how much sleep we get each night, and the dangers to our health of not getting enough, but really, there is another way

Feedback is excited to learn that University of Maryland researchers are measuring farts in a bid to build a Human Flatus Atlas, a project that seems destined for an Ig Nobel

Post-apocalyptic bunker sci-fi is huge this year as TV front-runners Fallout, Paradise and Silo return. Bethan Ackerley asks whether this is a signal we’ve given up on our real world, or if there is hidden hope

The books, TV, games and more that New Scientist staff have enjoyed this week

NASA crew members practise emergency rescue drills in a 40-foot-deep pool simulating the lunar surface, as part of tests on a new generation of spacesuit, the Axiom Extravehicular Mobility Unit

From ice ages to asteroid strikes, an epic book shows how important it has been for humans to look outwards. Alex Wilkins surveys a climate historian's cosmic sweep

This week’s Jesus and Mo strip, called “bells,” came with a comment: “Does she think they were born yesterday?”

Wikipedia tells us that another word for “conceptual conservatism” is “belief perseverance,” and characterizes it this way:

Belief perseverance (also known as conceptual conservatism) is maintenance of a belief despite new information that firmly contradicts it.[2]

Since rationality involves conceptual flexibility, belief perseverance is consistent with the view that human beings act at times in an irrational manner. Philosopher F.C.S. Schiller holds that belief perseverance “deserves to rank among the fundamental ‘laws’ of nature”.

The data adduced by the barmaid are under the heading “evidence from experimental psychology,” and she’s right, though it doesn’t cite “hundreds of studies”.

Not long ago I was asked by Jason Flores-Williams to contribute to his online/free paper newsletter Alma Asfalto, a Mexican publication (translation: “asphalt soul”) that has English translation. Flores-Williams wanted me to answer a few questions about evolution, and I agreed for two reasons. First, I wanted to help promote the understanding and acceptance of evolution among our southern neighbors. Second, if you click on the first link (to Wikipedia), you’ll see that Flores-Williams is a guy worth helping:

 Jason Flores-Williams (born 1969, Los Angeles, CA) is an author, political activist, and civil rights attorney. He is best known for his legal work on behalf of death row clients, political protesters, the homeless population of Denver, and his suit to have the Colorado River recognized as a legal person. Flores-Williams is an acknowledged expert in conspiracy law and First Amendment cases whose views are frequently sought by media organizations, including the Washington Post, the New York Times, and the Los Angeles Times. He was also a lead organizer of the protests against the 2004 Republican National Convention. He lives in Denver, Colorado.

How could I refuse a guy who did that? And so I agreed, answering his five questions. These answers appear on pp. 6-7 of the 16-page March edition of the paper, along with interviews and short essays by other scientists and humanities folks (these include author and filmmaker Sasha Sagan, the daughter of Carl Sagan and Ann Druyan). I’ll give here the five questions I was asked, but to see my answers you must to the paper by clicking on the screenshot below. (You can also download the whole paper. Warning: the site loads slowly.)  

Here are the questions I was asked. Again, see the answers at the site.

• In the simplest terms, what is evolution—and what do people most often get wrong about it?
• Why does evolution still make some people uncomfortable, even though it’s one of the most well-supported ideas in all of science?
• Does accepting evolution make human life feel less meaningful—or, in your view, more remarkable?
• People sometimes say that evolution promotes selfishness or brutality. What does evolution actually tell us about cooperation, empathy, and morality?
• If you could change one thing about how evolution is taught or talked about in public life, what would it be—and why does it matter right now?

Here are the contents:

Mexico City
March 2026 

Reality is being branded.
Truth manipulated.
Disengagement marketed.
But something real is gathering.

Across science, philosophy, art, and film, the real is now contested ground.

https://almaasfalto.com/marzo/

REALITY

Sasha Sagan
— The Integrity of Uncertainty

Zona Maco
— Art Week, Mexico City

Jerry Coyne
— Evolution and Meaning

Vlatko Vedral
— The Universe Owes You No Certainty

Asya Geisberg
— Necessary Friction

Franco “Bifo” Berardi
— Desertion from the Future

Kevin Anderson
— Against the Illusion

Mariana Rondón
— It Is Still Night in Caracas

Sarah Martinez
— Alchemist of Nothingness (FR/ES)

Printed in Mexico City.
Alma Asfalto circulates in Roma, in the Historic Center, and underground, on Metro platforms.

 

The alvarezsaurs were thought to have evolved a smaller stature because of their diet of ants and termites, but a new fossil found in Argentina casts doubt on that theory

The discovery of bright yet stable pigments is vanishingly rare, making them hugely valuable. Now chemist Mas Subramanian is unpicking the atomic code of colour and homing in on our most-wanted hue

Thinking about food systems in deep space likely brings to mind something like the Martian where an astronaut is scratching barely enough food to survive out of potatoes grown in Martian regolith. Or perhaps a fancy hydroponic system on an interplanetary transport ship, with artificial lighting and all the associated technological wizardry. But a new paper published in Acta Astronautica by Tor Blomqvist and Ralph Fritsche points out that growing food is only one small part of the whole cycle of providing sustenance for astronauts in space. To really get a sense of how difficult it will be, we have to look at the whole picture.

For two reasons I think that Jesse Singal‘s long op-ed (really a “guest essay”) in today’s NYT will mark a turning point in public and professional attitudes towards “affirmative care.”  First, the NYT saw fit to publish a piece showing that many American medical associations have promoted “affirmative care” of gender-dysphoric adolescents, despite those associations knowing that there was little or no evidence for the efficacy of such care.  Indeed, it seems that some of those associations lied or dissimulated about it, all in the interest of pushing a “progressive” ideology. As we know, left-wing “progressives” have been in favor of immediately accepting a child’s self-identification as belonging to its non-natal gender, so that teachers, parents, therapists, and doctors have united to start such children on puberty blockers and, later, surgery and hormones.

The NYT, while it has published pieces questioning the evidence for affirmative care, has been reluctant to come out as strongly as Singal does in the essay. That America’s Paper of Record deems this worthy of publication is news in itself.

For a number of reasons, most concerned with recent evidence (e.g., the Cass Review), the rah-rah affirmative therapy treadmill is grinding to a halt.  As Singal relates, recently two American medical associations—the American Society of Plastic Surgeons (ASPS) and now the powerful American Medical Association (AMA)—have admitted that we don’t know whether a gender-dyphoric child will “resolve” as gay or non-trans without medical intervention, and also that there should be no surgical intervention aimed at altering the gender of minors.

Singal has long called attention to these problems, and for his troubles he’s been branded a “transphobe,” shunned and blocked on social media.  There was even a petition to ban him from the site Bluesky, though, thank Ceiling Cat, it didn’t work.  Now, at long last, his views are getting a respectful airing, and society is coming to realize that the American zeal for “affirmative care”—not shared so much in Europe—is not only misguided but harmful.

The second reason is that the author ID says this about Singal:

Jesse Singal is writing a book about the debate over youth gender medicine in the United States and writes the newsletter Singal-Minded.

Although he’s already written one book. The Quick Fix: Why Fad Psychology Can’t Cure Our Social Ills, this is his first book on gender medicine, and if it expands on the theme of this article, it will be a landmark work with the potential to create big changes in gender medicine and how we view it.  Yes, it’s true that gender ideologues will oppose the article and upcoming book, but they have long put ideology over science, a strategy that is a loser, as we know from the failures of creationism and intelligent design.

Click on the headlines to read the article at the NYT, or find it archived for free at this site.

A few excerpts:

It didn’t matter that the number of kids showing up at gender clinics had soared and that they were more likely to have complex mental health conditions than those who had come to clinics in years earlier, complicating diagnosis. Advocates and health care organizations just dug in. As a billboard truck used by the L.G.B.T.Q. advocacy group GLAAD proclaimed in 2023, “The science is settled.” The Human Rights Campaign says on its website that “the safety and efficacy of gender-affirming care for transgender and nonbinary youth and adults is clear.” Elsewhere, these and other groups, like the American Civil Liberties Union, referred to these treatme

. . .The science doesn’t seem so settled after all, and it’s important to understand what happened here. The approach of left-of-center Americans and our institutions — to assume that when a scientific organization releases a policy statement on a hot-button issue, that the policy statement must be accurate — is a deeply naïve understanding of science, human nature and politics, and how they intersect.

At a time when more and more Americans are turning away from expert authority in favor of YouTube quacks and their ilk — and when our own government is pushing scientifically baseless policies on childhood vaccination and climate change — it’s vital that the organizations that represent mainstream science be open, honest and transparent about politically charged issues. If they aren’t, there’s simply no good reason to trust them.

And then Singal documents how organizations representing mainstream science and medicine haven’t been so trustworthy. The American Academy of Pediatrics (AAP) has been particularly  vocal—and clueless—in relentlessly pushing affirmative care:

A 2018 policy statement by the American Academy of Pediatrics provides a useful example of how these documents can go wrong. At one point, it argues that children who say they are trans “know their gender as clearly and as consistently as their developmentally equivalent peers,” an extreme exaggeration of what we know about this population. (A single study is cited.) The document also criticizes the “outdated approach in which a child’s gender-diverse assertions are held as ‘possibly true’ until an arbitrary age” — the A.A.P. was instructing clinicians to take 4- and 5-year-olds’ claims about their gender identities as certainly true. It’s understandable why the Cass reviewers scored this policy statement so abysmally, giving it 12 out of 100 possible points on “rigor of development” and six out of 100 on “applicability.”

Policy statements like this one can reflect the complex and opaque internal politics of an organization, rather than dispassionate scientific analysis. The journalist Aaron Sibarium’s reporting strongly suggests that a small group of A.A.P. members, many of whom were themselves youth gender medicine providers, played a disproportionate role in developing these guidelines.

Dr. Julia Mason, a 30-year member of the organization, wrote in The Wall Street Journal, with the Manhattan Institute’s Leor Sapir, that the A.A.P. deferred to activist-clinicians and stonewalled the critics’ demands for a more rigorous approach. Dr. Sarah Palmer, an Indiana-based pediatrician, told me she recently left the A.A.P. after nearly 30 years because of this issue. “I’ve tried to engage and be a member and pay that huge fee every year,” she said. “They just stopped answering any questions.” This is unfortunate given that, as critics have noted, in many cases the A.A.P. document’s footnotes don’t even support the claims being made in the text.

In the face of a lack of studies supporting their preferred ideology, organizations like the American Psychological Association (APA) have waffled, weaseled, and dissimulated, sometimes making contradictory statements.  Here’s one example (the AMA has also changed its stand but wouldn’t give Singal an interview). Bolding is mine:

The A.P.A. presents a particularly striking case of why transparency is important. In 2024 it published what it hailed as a “groundbreaking policy supporting transgender, gender diverse, nonbinary individuals” that was specifically geared at fighting “misinformation” on that subject. But when I reached out to the group this month, it pointed me to a different document, a letter written by the group’s chief advocacy officer, Katherine McGuire, in September in response to a Federal Trade Commission request for comment on youth gender medicine.

The documents, separated by about a year and a half (and, perhaps as significantly, one presidential election), straightforwardly contradict each other. The A.P.A. in 2024 argued that there is a “comprehensive body of psychological and medical research supporting the positive impact of gender-affirming treatments” for individuals “across the life span.” But in 2025, the group argued that “psychologists do not make broad claims about treatment effectiveness.”

In 2024 the A.P.A. criticized those “mischaracterizing gender dysphoria as a manifestation of traumatic stress or neurodivergence.” In 2025 it cautioned that gender dysphoria diagnoses could be the result of “trauma-related presentations” rather than a trans identity and that “co-occurring mental health or neurodevelopmental conditions (e.g., depression, anxiety, autism spectrum disorder) … may complicate or be mistaken for gender dysphoria.” It seems undeniable that the 2025 A.P.A. published what the 2024 A.P. A. considered to be “misinformation.” (“The 2024 policy statement and the 2025 F.T.C. letter are consistent,” said Ms. McGuire in an email, and “both documents reflect A.P.A.’s consistent commitment to evidence-based psychological care.”)

Behavior like this should anger anyone wedded to evidence-based medicine and science, especially because the APA simply lies when it says that its stand has been consistent all along. And the APA is not alone in its bad behavior.  Other organizations are digging in their heels, maintaining unsupportable positions in the face of counterevidence—all because of the ideology that people can change sex and we should believe them when they say they are really of a different sex than their natal one. This is wedded to the view that surgery and hormones designed to change gender have been proven to be safe.

I should add here that many adults who have transitioned are nevertheless happy with the outcomes of their treatments. But note that Singal’s forthcoming book is about youth gender medicine. This is the focus of the controversy, and few people (certainly not me) would deny adults the right to go ahead with surgery and hormones, though perhaps the public shouldn’t have to pay for it.

Singal’s conclusion, which I hope is the theme of his book, is short and sweet:

Should we trust the science? Sure, in theory — but only when the science in question has earned our trust through transparency and rigor.

  It looks like most medical organizations should not be trusted until they start speaking the truth.

It seems that the southern hemisphere gets all the good comets. A bashful binocular comet is about to finally leave its southern perch, and briefly come into view for folks up north. Said comet of the moment is C/2023 E1 Wierzchos. Although the comet just passed perihelion last week, it should put on a fine encore show as it heads north in March at dusk.

Plant lovers and botanists will be especially pleased by today’s selection of lovely photos from Thomas Webber. Thomas’s captions and IDs are indented, and you can enlarge the photos by clicking on them (recommended).

The theme for today’s installment is Gone to Seed. Here are a few north-Florida flowers shown in their prime and afterward, when their glamor parts had been replaced by seed enclosures, bare seeds, or merely the dried remains of the flower bases. All of them grew within Gainesville’s city limits, at sites from semi-pruned to semi-wild. I think I’ve identified them all correctly to species this time, but I invite corrections.

Frostweed, Verbesina virginica. Individual flowers 1 cm. Native:

These bracts, called phyllaries, surround the bases of the flowers. In late February a few of their papery remnants are still aloft on their brittle four-foot stalks:

Low rattlebox, Crotalaria pumila. 2.5 cm across. Native. The map in the article linked here is incomplete and does not reflect the herbarium records for Alachua County, where I took this picture.

Showy rattlebox. C. spectabilis. 3.5 cm across. Native to southern and southeast Asia, now widely naturalized in southeastern North America:

C. spectabilis seed pods. 4 cm long. The pods of C. pumila look similar but are smaller. Crotalaria, and especially their seeds, are laden with toxic alkaloids. Larvae of the rattlebox moth, Utetheisa ornatrix, bore through the walls of the pods and feed on the seeds. Somehow the caterpillars manage to detoxify the alkaloids enough so they aren’t poisoned, while remaining poisonous enough to deter most animals that might try to eat them. The larvae retain the toxins into the flying-moth stage, and at both stages their distinctive vivid color pattern warns predators to leave them alone.

A rattlebox-moth caterpillar. About 3 cm. I doubt that I could have found any of these if I’d gone looking for them, but this one crawled right in front of me while I tried to get a picture of the low rattlebox. It held fairly steady for a few seconds, letting me capture enough detail to identify it. I didn’t have my choice of background:

Tropical sage, Salvia coccinea. 3 cm. Native. At this latitude these remain at their peak through late December:

All that’s left in late February are these cones called calyces, which are fused sepals:

Spanish needles, Bidens alba. 2.5 cm. Native. This is the king weed of these parts, growing everywhere and sometimes in great masses; one dense bunch covers an acre of a low damp lot in the middle of Gainesville:

Seeds of Spanish needles. 1 cm long. The name of the genus, meaning two-teeth, derives from the forks at the tips of the seeds. The barbs on these projections are part of an impressive example of convergent biological and cultural evolution, and have turned out to be just the thing for attaching the seeds to socks and shoelaces:

Dotted horsemint, Monarda punctata. Whole flower head 2.5 cm wide. Native. The most complicated flowers I find around here:

All of that elaborate presentation goes to produce seeds 1 mm in diameter, too small to show well with my basic macro gear. At this stage you can still shake a few of them from the calyces. Thanks to Mark Frank of the Florida Museum of Natural History herbarium for a remedial lesson in the difference between calyces and phyllaries:

Beggarweed, Desmodium incanum. 1 cm across. Native to Central- and South America, naturalized in the southeastern U.S. This year, by means unknown, a few of them showed up for the first time in what passes for my lawn:

Beggarweed pea-pods, 3 cm long:

Scarlet morning glory, Ipomoea hederifolia. 4 cm long. Native:

Morning-glory seed pods, 7 mm. The hard little capsules cleave along their sutures and split open to release black seeds the shape of orange sections, exposing the translucent porcelain-like septa that divided them:

Mars’ frozen ice caps may be time capsules for ancient life. Lab experiments show that key building blocks of proteins can survive tens of millions of years in pure ice, even under relentless cosmic radiation. Ice mixed with Martian-like soil, however, destroys organic material far more quickly. The findings point future missions toward drilling into clean, buried ice rather than studying rocks or dirt.

Glyphosate is the most used herbicide in the world, with farmer applying about 750 million kg per year. The US is the heaviest user, responsible for 19% of global use. The chemical is popular among industrial farmers because it is safe and effective, and yet it also remains highly controversial. It is also back in the news, and so an update on […]

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