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This is the result of a dispute I’ve explained before (see here). Because the FFRF has caved into to gender extremism, an area having nothing to do with its mission, and because, when they let me post an article on their website about this, they changed their mind and simply removed my post, I have decided I can no longer remain a member of their board of honorary directors.  So be it. Everything is explained in this email I sent FFRF co-Presidents Annie Laurie Gaylor and Dan Barker about an hour ago, to wit:

Dear Annie Laurie and Dan,

As you probably expected, I am going resign my position on the honorary board of the FFRF.  I do this with great sadness, for you know that I have been a big supporter of your organization for years, and was honored to receive not only your Emperor Has No Clothes Award, but also that position on your honorary board.

But because you took down my article that critiqued Kat Grant’s piece, which amounts to quashing discussion of a perfectly discuss-able issue, and in fact had previously agreed that I could publish that piece—not a small amount of work—and then put it up after a bit of editing, well, that is a censorious behavior I cannot abide. I was simply promoting a biological rather than a psychological definition of sex, and I do not understand why you would consider that “distressing” and also an attempt to hurt LGBTQIA+ people, which I would never do.

As I said, I think these folks should have moral and legal rights identical to those of other groups, except in the rare cases in which LGBTQIA+ rights conflict with the rights of other groups, in which case some kind of adjudication is necessary. But your announcement about the “mistake” of publishing my piece also implies that what I wrote was transphobic.

Further, when I emailed Annie Laurie asking why my piece had disappeared (before the “official announcement” of revocation was issued), I didn’t even get the civility of a response. Is that the way you treat a member of the honorary board?

I always wanted to be on the board so I could help steer the FFRF: I didn’t think of it as a job without any remit. The only actions I’ve taken have been to write to both of you—sometimes in conjunction with Steve, Dan (Dennett), or Richard—warning of the dangers of mission creep, of violating your stated goals to adhere to “progressive” political or ideological positions. Mission creep was surely instantiated in your decision to cancel my piece when its discussion of biology and its relationship to sex in humans violated “progressive” gender ideology. This was in fact the third time that I and others have tried to warn the FFRF about the dangers of expanding its mission into political territory. But it is now clear that this is exactly what you intend to do. Our efforts have been fruitless, and if there are bad consequences I don’t want to be connected with them.

I will add one more thing. The gender ideology which caused you to take down my article is itself quasi-religious, having many aspects of religions and cults, including dogma, blasphemy, belief in what is palpably untrue (“a woman is whoever she says she is”), apostasy, and a tendency to ignore science when it contradicts a preferred ideology.

I will continue to struggle for the separation of church and state, and wish you well in that endeavor, which I know you will continue. But I cannot be part of an organization whose mission creep has led it to actually remove my words from the internet—words that I cannot see as harmful to any rational person.  I am not out to hurt LGBTQIA+ people, and I hope you know that. But you have implied otherwise, and that is both shameful for you and hurtful for me.

Cordially
Jerry

For centuries, comets have captured our imagination. Across history they have been the harbingers of doom, inspired artists and fascinated astronomers. These icy remnants of the formation of the Solar System hold secrets to help us understand the events nearly 5 billion years ago. But before these secrets can be revealed, comets have to be studied and to study them they need to be found. A team of researchers have developed a technique to hunt down comets based upon data from meteor showers and to asses if they pose any threat to us here on Earth!

Comets are objects that orbit the Sun like the planets but their orbits are usually more elliptical. They are composed of dust, gas and water ice and often called ‘dirty snowballs.’ Many comets are part of, or were a part of the Oort Cloud or Kuiper Belt. These distant regions of space house many of the Solar System’s icy bodies. On occasions, interactions between the bodies in the clouds can send chunks in toward the inner Solar System transforming the dormant chunks of rock and ice into the comets we recognise. Driven by heating from the Sun, the ice immediately sublimates into a gas giving rise to a comets familiar fuzzy coma and tail. Contrary to popular belief, the tail of a comet doesn’t stream out behind the comet as it travels through space, instead, it always points away from the Sun pushed in that direction by the Solar Wind. 

Geysers of dust and gas shooting off the comet’s nucleus are called jets. The volatile material they deliver outside the nucleus builds the comet’s coma. Credit: ESA/Rostta/NAVCAM

Comets are categorised as either short period comets or long period with the latter group having an orbit of more than 200 years. Due to their long orbits, scientists fear that one  will be on a collision course with Earth and go completely un-noticed until it is too late.  The risk of this occurrence is of course incredibly small but the impact could be catastrophic to life on Earth. A team of astronomers led by Samantha Hemmelgarn from the Northern Arizona University has published a paper in Planetary Science Journal where they explain their technique for identifying threats from long period comets using  data from meteor showers. 

Leonids meteor shower

“This research gets us closer to defending Earth because it gives us a model to guide searches for these potentially hazardous objects,” Hemmelgarn said. Meteor showers occur when the Earth passes through the debris left behind by a comet. The team has studied 17 meteor showers that are associated with long period comets and calculated where the parent comet should be in space.

Using the path of the meteor showers, the team can assess the liklihood that a long period comet could pose a threat over its future orbits. In the test cases, the model accurately predicted the comet locations including its direction and speed of travel. This provides the opportunity for astronomers to hone their search around the sky looking for long period comets rather than hope one might be spotted through automated searchers that scour the whole sky. 

The obvious benefit is that early identification of a comet on a collision course with Earth means that there is more time to develop a plan for our defence. There is nothing yet that provides any concern for astronomers but the next impact event of extinction level, may be millions of years away. The team hope that their work and model will help to provide humanity with the earliest warning of potential impacts. 

Source : How to Find a Comet Before it Hits Earth

The post Meteor Showers May One Day Help Protect Humanity! appeared first on Universe Today.

Today is the last Sunday of the year, which means that we have John Avise‘s last post of the year (he will of course continue in 2025).  Right now he’s showing photos of American lepidopterans. John’s captions are indented, and you can enlarge his photos by clicking on them.

Butterflies in North America, Part 4 

First, I’d like to wish all WEIT readers a Happy New Year and a wonderful 2025.  This week continues my many-part series on butterflies that I’ve photographed in North America.  I’m continuing to go down my list of species in alphabetical order by common name.

California Sister (Adelpha californica):

California Sister, underwing:

California Tortoiseshell (Nymphalis californica):

Callippe Fritillary (Speyeria callippe):

Callippe Fritillary underwing:

Carolina Satyr (Hermeuptychia sosybius):

Carolina Satyr underwing:

Cassius Blue (Leptotes cassius), underwing:

Ceraunus Blue (Hemiargus ceraunus), male, topwing:

Ceraunus Blue, underwing:

Checkered White (Pontia protodice), male:

Checkered White, female:

Checkered White, female underwing:

Good morning on Sunday, December 29, 2024, the penultimate day of Coynezaa, which ends tomorrow with a milestone birthday for PCC(E).  Today we will have a brief Hili post, but there will be readers’ wildlife, a regular post (this one on the osculation of faith), and an announcement.  All is well, and tomorrow or Tuesday we’ll be back in business.

It’s also National Pepper Pot Day, celebrating a soup said to be created on this day in 1777 when George Washington sent his cook out to forage for something that could warm and nourish his freezing soldiers overwintering at Valley Forge. This soup was the result, though Wikipedia has a different origin tale.

Readers are welcome to mark notable events, births, or deaths on this day by consulting the December 29 Wikipedia page.

Da Nooz:

There is only one item of news for us today:  there has been another plane crash, this time in South Korea, and the death toll is high. On the news this morning they attributed it to a bird strike. Two people survived, both members of the crew:

A passenger plane crashed while landing at an airport in southwestern South Korea on Sunday, killing most of the 181 people on board in the worst aviation disaster involving a South Korean airline in almost three decades, officials said.

The Boeing 737-800 plane, operated by South Korea’s Jeju Air, had taken off from Bangkok and was landing at Muan International Airport when it crashed at around 9 a.m. local time. Footage of the accident shows a white-and-orange plane speeding down a runway on its belly until it overshoots the runway, hitting a barrier and exploding into an orange fireball.

Officials were investigating what caused the tragedy, including why the plane’s landing gear appeared to have malfunctioned, whether birds had struck the jet, or if bad weather had been a factor.

The airport in Muan had warned the plane’s pilots about a potential bird strike as they were landing, said Ju Jong-wan, a director of aviation policy at the Ministry of Land, Infrastructure and Transport. The plane issued a mayday alert shortly afterward, then crash-landed, he added, saying later that the plane’s black boxes — which should help determine the cause of the crash — have been recovered.

Jeju Air flight 7C2216 had 175 passengers and six crew members on board. Hundreds of people — grandparents, parents and children — packed the Muan airport waiting anxiously for news about their loved ones.

As of Sunday evening, the government said, 177 people had been confirmed dead, including 22 Korean nationals identified by their fingerprints. The names of the dead were posted on lists in the airport as relatives crowded around.

More than 1,500 people were deployed to help search the wreckage; at least two crew members were rescued from the aircraft’s tail section.

Lee Jeong-hyeon, an official in charge of search and rescue operations at the scene, said the plane had broken into so many pieces that only its tail was identifiable.

“We could not recognize the rest of the fuselage,” he said.

Meanwhile in Dobrzyn, Hili and Szaron are almost in hibernation:

A: Lately you are in bed day and night. Hili: We are waiting for spring.

In Polish: Ja: Ostatnio w dzień i w nocy jesteście na łóżku. Hili: Czekamy na wiosnę.

When I wrote yesterday about my critique of Kat Grant’s “What is a woman?” piece, a critique published on the Freedom from Religion Foundation’s (FFRF) website, I had no idea that what I wrote was being removed by the FFRF at that moment! I’m not going into a long exegesis here, as I’ll have more to say about this affair elsewhere.  But here are the relevant links:

“What is a woman?“: The original FFRF post on Freethought Today! by Kat Grant, an intern with the FFRF.

“Biology is not bigotry“: My response to Grant’s piece on Freethought Today!. The link is an archived one because the original post is gone. You can also find it archived here. Also, because a reader suggested that archived pieces could be removed, I’ve added a transcript of my final published piece below the fold of this article. 

When some readers pointed out yesterday that “Biology is not bigotry” was no longer online, I had no idea what happened, and assumed they had relocated the post. I was unable to believe that they would actually remove my post, especially because FFRF co-President Annie Laurie Gaylor had given me permission to write it and approved the final published version.

I emailed Annie Laurie inquiring what had happened to my piece. I never got a response—or rather, they didn’t have the human decency to write me back personally. They still have not done so, and now they shouldn’t bother. Instead, they sent out the following notice to all FFRF members (it’s also archived here):

 

Note first that when they refer to my piece, they mention neither who wrote the piece or what it was about. If I’m to be cancelled for what I wrote, dammit, I want my NAME and TOPIC mentioned!

Several things are clear, including a point I’ve made before: the FFRF has a remarkable ability to place any kind of antiwoke ideology under the rubric of “Christian nationalism.” That’s why I wrote in my now-expunged piece, “As a liberal atheist, I am about as far from Christian nationalism as one can get!”  And of course I support LGBTQIA+ rights, save in those few cases where those rights conflict with the rights of other groups, as in sports participation. I doubt that even the FFRF would think that women should be boxing, professionally or in the Olympics, against men or biological men who identify as women.  So in terms of “LGBTQIA-plus rights,” I’m pretty much on the same plane as the FFRF, even though they imply I’m not.

But it’s the last six paragraphs of the FFRF’s post where they explain why they took down my piece.  It is because it caused “distress” and “did not reflect [the FFRF’s] values or principles.”  I’m not sure what values or principles my piece failed to reflect. Does the FFRF think that sex is really a spectrum, that there are more than two sexes in humans, or that the most useful definition of biological sex doesn’t involve gamete size? I don’t know, nor do they say.

As for my words causing “distress,” well, I’m sorry if people feel distress when I explicate the biological definition of sex or estimate how few people fail to adhere to the sex binary.  But this is all material not for censorship but for back-and-forth discussion, especially on a site called “Freethought Now!” (Should it be called “Freeethought Not!” instead?)

And that is what disappoints me most: not just the “mission creep” instantiated by the FFRF’s incursion into partisan politics or dubious ideology, but the fact that they will not allow free and civil discussion about an article that they published, an article that concludes by saying, “A woman is whoever she says she is.”  If that is not a statement ripe for discussion, then what is? It is only fear that would make an organization take down a rational discussion of such a contentious statement. I don’t know what the FFRF is afraid of, but I am just a biologist defending my turf, and am not by any means bent on hurting LGBTAIA+ people.

I’m distressed that it’s come to this, as I’ve always been a big supporter of the FFRF and its historical mission, which is, I suppose, why they made me an honorary director and gave me the Emperor Has No Clothes Award. And I will always support their activities that genuinely try to keep church and state separate. But when they start censoring my words because, though biologically justifiable, they are ideologically unpalatable, that is just too much. All I can say now is that this is not the end of this kerfuffle, and that I stand by what I wrote before.

How sad it is that one of the nation’s premier organizations promoting “freethought” won’t permit that kind of thought on their website, but instead quashes what they see as “wrongthink.”

 

Click “continue reading” to see a transcript my original published piece.

•  Freedom From Religion Foundation
• December 26, 2024

 

Disclaimer: FFRF Honorary Board Member Jerry A. Coyne requested that this column be written as a guest blog. The views in this column are of the author and do not necessarily reflect those of the Freedom From Religion Foundation.

Biology is not bigotry
By Jerry A. Coyne

In the Freethought Now article “What is a woman?”, author Kat Grant struggles at length to define the word, rejecting one definition after another as flawed or incomplete. Grant finally settles on a definition based on self-identity: “A woman is whoever she says she is.” This of course is a tautology, and still leaves open the question of what a woman really is. And the remarkable redefinition of a term with a long biological history can be seen only as an attempt to force ideology onto nature. Because some nonbinary people — or men who identify as women (“transwomen”) — feel that their identity is not adequately recognized by biology, they choose to impose ideology onto biology and concoct a new definition of “woman.”

Further, there are plenty of problems with the claim that self-identification maps directly onto empirical reality. You are not always fat if you feel fat (the problem with anorexia), not a horse if you feel you’re a horse (a class of people called “therians” psychologically identify as animals), and do not become Asian simply become you feel Asian (the issue of “transracialism”). But sex, Grant tells us, is different: It is the one biological feature of humans that can be changed solely by psychology.

But why should sex be changeable while other physical traits cannot? Feelings don’t create reality. Instead, in biology “sex” is traditionally defined by the size and mobility of reproductive cells (“gametes”). Males have small, mobile gametes (sperm in animals and pollen in plants); females have large, immobile gametes (ova in plants and eggs in animals). In all animals and vascular plants there are exactly two sexes and no more. Though a fair number of plants and a few species of animals combine both functions in a single individual (“hermaphrodites”), these are not a third sex because they produce the typical two gametes.

It’s important to recognize that, although this gametic idea is called a “definition” of sex, it is really a generalization — and thus a concept — based on a vast number of observations of diverse organisms.  We know that, except for a few algae and fungi, all multicellular organisms and vertebrates, including us, adhere to this generalization. It is, then, nearly universal.

Besides its universality, the gametic concept has utility, for it is the distinction between gamete types that explains evolutionary phenomena like sexual selection. Differential investment in reproduction accounts for the many differences, both physical and behavioral, between males and females. No other concept of sex has such universality and utility. Attempts to define sex by combining various traits associated with gamete type, like chromosomes, genitalia, hormones, body hair and so on, lead to messy and confusing multivariate models that lack both the universality and explanatory power of the gametic concept.

Yes, there is a tiny fraction of exceptions, including intersex individuals, who defy classification (estimates range between 1/5,600 and 1/20,000). These exceptions to the gametic view are surely interesting, but do not undermine the generality of the sex binary. Nowhere else in biology would deviations this rare undermine a fundamental concept. To illustrate, as many as 1 in 300 people are born with some form of polydactyly — without the normal number of ten fingers.  Nevertheless, nobody talks about a “spectrum of digit number.” (It’s important to recognize that only a very few nonbinary and transgender people are “intersex,” for nearly all are biologically male or female.)

In biology, then, a woman can be simply defined in four words: “An adult human female.”

Dismissal of trait-based concepts of sex leads to serious errors and misconceptions. I mention only a few. The biological concept of a woman does not, as Grant argues, depend on whether she can actually produce eggs. Nobody is claiming that postmenopausal females, or those who are sterile or had hysterectomies, are not “women,” for they were born with the reproductive apparatus that evolved to produce eggs. As for chromosomes, having two X chromosomes gives you a very high probability of being a woman, but a rearrangement of genetic information can decouple chromosome constitution from the gametic apparatus.

But the biggest error Grant makes is the repeated conflation of sex, a biological feature, with gender, the sex role one assumes in society. To all intents and purposes, sex is binary, but gender is more spectrum-like, though it still has two camel’s-hump modes around “male” and “female.” While most people enact gender roles associated with their biological sex (those camel humps), an appreciable number of people mix both roles or even reject male and female roles altogether. Grant says that “I play with gender expression” in “ways that vary throughout the day.” Fine, but this does not mean that Grant changes sex from hour to hour.

Under the biological concept of sex, then, it is impossible for humans to change sex — to be truly “transsexual” — for mammals cannot change their means of producing gametes. A more appropriate term is “transgender,” or, for transwomen, “men who identify as women.”

But even here Grant misleads the reader. They argue, for example, that “Transgender people are no more likely to be sexual predators than other individuals.” Yet the facts support the opposite of this claim, at least for transgender women. A cross-comparison of statistics from the U.K. Ministry of Justice and the U.K. Census shows that while almost 20 percent of male prisoners and a maximum of 3 percent of female prisoners have committed sex offenses, at least 41 percent of trans-identifying prisoners were convicted of these crimes. Transgender, then, appear to be twice as likely as natal males and at least 14 times as likely as natal females to be sex offenders. While these data are imperfect because they’re based only on those who are caught, or on some who declare their female gender only after conviction, they suggest that transgender women are far more sexually predatory than biological women and somewhat more predatory than biological men. There are suggestions of similar trends in Scotland, New Zealand, and Australia.

Biological sex affects who and what we are. Let’s look at the contentious area of sports participation.  Here’s a summary of the current regulatory situation (from a link that Grant gives):

“For the Paris 2024 Olympics, the new guidelines require transgender women to have completed their transition before the age of 12 to be eligible to compete in the women’s category. This rule is intended to prevent any perceived unfair advantages that might arise from undergoing male puberty.”

“In addition, at least 10 Olympic sports have restricted the participation of transgender athletes. These include sports like athletics, cycling, swimming, rugby, rowing, and boxing.”

Completing transition before 12 is virtually unknown (26 American states ban childhood transition), and the International Olympic Committee has now asked each sport to devise its own rules. Further, the presence of “regulation” does not make the problem go away, for many regulations are insufficient to protect female athletes from male athletic advantage. According to a United Nations report on violence against women, “By 30 March 2024, over 600 female athletes in more than 400 competitions have lost more than 890 medals [to transgender women] in 29 different sports.”

I close with two points. The first is to insist that it is not “transphobic” to accept the biological reality of binary sex and to reject concepts based on ideology. One should never have to choose between scientific reality and trans rights. Transgender people should surely enjoy all the moral and legal rights of everyone else. But moral and legal rights do not extend to areas in which the “indelible stamp” of sex results in compromising the legal and moral rights of others. Transgender women, for example, should not compete athletically against biological women; should not serve as rape counselors and workers in battered women’s shelters; or, if convicted of a crime, should not be placed in a women’s prison.

Finally, speaking as a member of the FFRF’s honorary board, I worry that the organization’s incursion into gender activism takes it far outside its historically twofold mission: educating the public about nontheism and keeping religion out of government and social policies. Tendentious arguments about the definition of sex are not part of either mission. Although some aspects of gender activism have assumed the worst aspects of religion (dogma, heresy, excommunication, etc.), sex and gender have little to do with theism or the First Amendment. I sincerely hope that the FFRF does not insist on adopting a “progressive” political stance, rationalizing it as part of its battle against “Christian Nationalism.” As a liberal atheist, I am about as far from Christian nationalism as one can get!

Issues of sex and gender cannot and should not be forced into that Procrustean bed. Mission creep has begun to erode other once-respected organizations like the ACLU and SPLC, and I would be distressed if this happened to the FFRF.

Jerry A. Coyne is emeritus professor of Ecology and Evolution at the University of Chicago.

Note: The Hili Dialogues will be truncated over the next few days as I figure out how to respond to the FFRF’s removal of my piece on biological sex.  Bear with me; I do my best. I’m also not sure about readers’ wildlife and the Caturday felids.

Welcome to CaturSaturday, December 28, 2024, the fourth day of Coynezaa, which ends on the 30th, as well as National Chocolate Candy Day, which reminds me of this famous clip from “I Love Lucy”:

It’s also Call A Friend Day, National Card Playing Day, and Pledge of Allegiance Day, the latter celebrating our National Fealty to God (it was on this day in 1942 that Congress recognized the words of the pledge, but the “One Nation, Under God” bit was added only in 1954 in reaction to of Godless Communism.

Readers are welcome to mark notable events, births, or deaths on this day by consulting the December 19 Wikipedia page.

Da Nooz:

*As always, I’ll steal three items from Nellie Bowles’s weekly news summary at the Free Press, call this week, “TGIF: Welcome to America, Greenland.” And as the items are short, I’ll steal one more as lagniappe:

→ Sinwar shirts: Until people noticed and got annoyed, Walmart was selling shirts online celebrating Hamas leader Yahya Sinwar with the not-at-all alarming URL: walmart.com/ip/Yahya-Sinwar-We-Will-Win-Or-Die-Shirt. Free shipping!

→ UN’s gonna UN: It was a busy year for the United Nations. It condemned Israel 17 times and condemned the rest of the world a combined six times, according to UN Watch. Afghanistan barred women from speaking, and the UN General Assembly couldn’t muster even one of their little fake resolution batons. Meanwhile, UNRWA, a Hamas front that calls itself part of the UN but is based in Gaza, is reportedly selling some of that desperately needed aid. The UN closes out the year stronger than ever.

→ Oh no, not flames! One Canadian headline writer was so determined to avoid saying that an arsonist firebombed a synagogue that they instead wrote this:

Flames. After what they did to that woman on the subway, they’ve had quite a villainous week! And a “place of worship.” If your media company just uses words to accurately describe what is happening, you’re considered a wild, rebellious group of thought criminals.

→ Gaetz situation unfortunate all around: The House Ethics Committee finally released its report on Matt Gaetz this week, giving America a Christmas gift that nobody asked for but everyone expected. The committee found evidence that Gaetz paid tens of thousands of dollars to women for sex and drugs, but also for companionship and tenderness. They allege it happened on at least 20 different occasions, one of which involved a 17-year-old girl, violating Florida state laws. This really caught me off guard. Paying minors for sex is illegal in Florida? Gaetz’s die-hard fans (who are these people?) defended him, arguing that two key witnesses against Gaetz have serious credibility issues, which, frankly, no surprises there, since they are 17? There’s nothing I didn’t lie about at that age. My question: Who do you think witnessed Gaetz at his Diddy freak-off–like parties? Honest church ladies? Think again. Gaetz, for his part, released a statement: “It’s embarrassing, though not criminal, that I probably partied, womanized, drank, and smoked more than I should have earlier in life. I live a different life now.”

He’s just an average frat boy, you see. Boys will be johns. And he’s repented, changed his ways. Nothing else to it. Embarrassing? Yes. Criminal? Probably. I’ll let the dust settle on this one, but for now, my main takeaway is that congresspeople have enough money to spend tens of thousands of dollars on women and drugs and still have the gall to demand a raise. Washington at work, people.

Meanwhile in Dobrzyn, Hili and Szaron are going to the salon:

A: What are you doing here? Hili: We are waiting for fur care. In Polish: Ja: Co tu robicie? Hili: Czekamy na pielęgnację futer.

*******************

From reader Reese Vaughn, who reports, “Woodford got a catnip ball for Christmas.”  That cat is baked!

From Now That’s Wild:

. . . and from Cat Memes:

2024 Year End Review; Best of 2024; Science Hero and Jackass of the Year; In Memoriam; Science or Fiction

In the coming years, NASA and other space agencies will send humans back to the Moon for the first time since the Apollo Era—this time to stay! To maximize line-of-sight communication with Earth, solar visibility, and access to water ice, NASA, the ESA, and China have selected the Lunar South Pole (LSP) as the location for their future lunar bases. This will necessitate the creation of permanent infrastructure on the Moon and require that astronauts have the right equipment and training to deal with conditions around the lunar south pole.

This includes lighting conditions, which present a major challenge for science operations and extravehicular activity (EVA). Around the LSP, day and night last for two weeks at a time, and the Sun never rises more than a few degrees above the horizon. This creates harsh lighting conditions very different from what the Apollo astronauts or any previous mission have experienced. To address this, the NASA Engineering and Safety Council (NESC) has recommended developing a wide variety of physical and virtual techniques that can simulate the visual experiences of Artemis astronauts.

In the past, the design of lighting and functional vision support systems has typically been relegated to the lowest level of program planning. This worked well for the Apollo missions and EVAs in Low Earth Orbit (LEO) since helmet design alone addressed all vision challenges. Things will be different for the Artemis Program since astronauts will not be able to avoid having harsh sunlight in their eyes during much of the time they spend doing EVAs. There is also the challenge of the extensive shadowing around the LSP due to its cratered and uneven nature, not to mention the extended lunar nights.

Artist’s rendering of the Starship HLS on the Moon’s surface. NASA has contracted with SpaceX to provide the lunar landing system. Credit: SpaceX

In addition, astronaut vehicles and habitats will require artificial lighting throughout missions, which means astronauts will have to transition from ambient lighting to harsh sunlight and/or intense darkness and back. Since the human eye has difficulty adapting to these transitions, it will impede an astronaut’s “function vision,” which is required to drive vehicles, perform EVAs safely, operate tools, and manage complex machines. This is especially true when it comes to rovers and the lander elevator used by the Starship HLS – both of which will be used for the Artemis III and IV missions.

As Meagan Chappell, a Knowledge Management Analyst at NASA’s Langley Research Center, indicates, this will require the development of new functional vision support systems. That means helmets, windows, and lighting systems that can work together to allow crews to “see into the darkness while their eyes are light-adapted, in bright light while still dark-adapted, and protects their eyes from injury.” According to the NESC assessment, these challenges have not been addressed, and must be understood before solutions can be implemented.

In particular, they indicated how functional vision and specific tasks for Artemis astronauts were not incorporated into system design requirements. For example, the new spacesuits designed for the Artemis Program – the Axiom Extravehicular Mobility Unit (AxEMU) – provide greater flexibility so astronauts can walk more easily on the lunar surface. However, there are currently no features or systems that would allow astronauts to see well enough when transitioning between brilliant sunlight into dark shadow and back again without losing their footing.

The NESC assessment identified several other gaps, prompting them to recommend that methods that enable functional vision become a specific and new requirement for system designers. They also recommended that the design process for lighting, windows, and visors become integrated. Lastly, they recommended that various physical and virtual simulation techniques be developed to address specific requirements. This means virtual reality programs that simulate what it is like to walk around the LSP during lunar day and night, followed by “dress rehearsal” missions in analog environments (or both combined!).

Astronauts operating around the Lunar South Pole. Credit: NASA

As Chappell summarized, the simulations will likely focus on different aspects of the mission elements to gauge the effectiveness of their designs:

“Some would address the blinding effects of sunlight at the LSP (not easily achieved through virtual approaches) to evaluate [the] performance of helmet shields and artificial lighting in the context of the environment and adaptation times. Other simulations would add terrain features to identify the threats in simple (e.g., walking, collection of samples) and complex (e.g., maintenance and operation of equipment) tasks. Since different facilities have different strengths, they also have different weaknesses. These strengths and limitations must be characterized to enable verification of technical solutions and crew training.”

This latest series of recommendations reminds us that NASA is committed to achieving a regular human presence on the Moon by the end of this decade. As that day draws nearer, the need for more in-depth preparation and planning becomes apparent. By the time astronauts are making regular trips to the Moon (according to NASA, once a year after 2028), they will need the best training and equipment we can muster.

Further Reading: NASA

The post NASA is Considering Designs and Simulations to Prepare Astronauts for Lighting Conditions Around the Lunar South Pole appeared first on Universe Today.

Here physicist Brian Greene argues with Sam Harris about approaches to dispelling false beliefs, aka religion. Greene argues that simply acquainting people with science will make them less religious (or at least he implies it), and avers that some New Atheists have been ineffective because they call religious people “stupid”. (That’s not so true!). Harris, however, says that the “carrot” attitude of Greene (and Greene really doesn’t use a carrot because he doesn’t criticize religous belief at all) may not be as effective as Harris’s “stick”, which is simply rational argument about what is true and open criticism of the harms of religion. As Sam says, it’s false to assert that you can’t reason people out of religion because he’s seen it happen. So have I.

Sam notes what seems to be the case: Greene just doesn’t want to be the “go-to guy for why you can’t have your cake and eat it too in the matter of science and religion.”  On the other hand, Sam notes that in some ways religion is bad for science. For example, some religious beliefs are inimical to understanding science, including accepting global warming. And of course creationism is still with us in the form of ID.  Sam then asks whether Greene shouldn’t be pushing harder against such inimical religious beliefs. Greene responds that in physics he doesn’t encounter that kind of religious mishigass, which is found more in biology. It’s more than that, though, because I believe that in the past Greene, as one of the organizers of the World Science Festival, has participated in osculating the rump of faith. As I wrote in 2020:

On the other hand [Greene] takes lots of money from the John Templeton Foundation to run the World Science Festival, and there’s always some Templeton-sponsored events that reconcile religion and science or enable “spirituality”.  In fact, Dan Dennett withdrew from a Festival panel when he learned it was backed by Templeton (see the first link in this sentence). And Greene has always been reluctant to say anything bad about religion, despite the fact that he seems to be an atheist. Although he’s said that “there’s much in New Atheism that resonates with me“, he’s admitted that his strategy is less confrontational and less antagonistic than scientists like Dawkins. In fact, as we see below, it no longer seems the least confrontational and antagonistic, but rather worshipful.

There’s more, but I think that one element in Greene’s reticence is knowing that if one criticizes religion, one loses popularity. The fastest way to erode one’s acclaim as a science writer or popularizer is to criticize religion, even if you do it separately from talking about science. Neil deGrasse Tyson has also learned that lesson.

 

An AI model that understands the interplay between human body language, speech and emotion enables digital avatars to move more realistically when speaking

Digital healthcare consultations are not enough for a safe assessment of tonsillitis, according to a new study. Reliability will not be sufficient, thus increasing the risk of over- or under-treatment of a sore throat.

By the end of the century, most of the US outside the high mountains may never see deep snow cover the ground, with consequences for water storage as well as for the life on and beneath the snow

There is growing interest in exploring ways to counteract global warming by intervening in the atmosphere and the oceans, but planned trials are highly controversial

Several prototype aircraft that are intended to bring back commercial supersonic travel have been making big strides in recent years – but it is unknown how well the return of Concorde-like flights will go down with customers

The time to start speaking out to defend vaccines from RFK Jr. is now.

The post Dr. Marty Makary, What Are You Going To Do If RFK Jr. Demands That Revoke Approval For Vaccines? first appeared on Science-Based Medicine.

A research group has analyzed the digital ecosystem of 11- to 12-year-old children across the Basque Autonomous Community, and concluded that two out of three own a smartphone. They use smartphones mainly to talk to family and friends. The researchers also point out that, at that age, access to social media mainly focuses on watching videos and not on generating content.

Bio-inspired wind sensing using strain sensors on flexible wings could revolutionize robotic flight control strategy. Researchers have developed a method to detect wind direction with 99% accuracy using seven strain gauges on the flapping wing and a convolutional neural network model. This breakthrough, inspired by natural strain receptors in birds and insects, opens up new possibilities for improving the control and adaptability of flapping-wing aerial robots in varying wind conditions.

Bio-inspired wind sensing using strain sensors on flexible wings could revolutionize robotic flight control strategy. Researchers have developed a method to detect wind direction with 99% accuracy using seven strain gauges on the flapping wing and a convolutional neural network model. This breakthrough, inspired by natural strain receptors in birds and insects, opens up new possibilities for improving the control and adaptability of flapping-wing aerial robots in varying wind conditions.

On December 23m I called attention to the huge amount of money that the John Templeton Foundation (JTF) was throwing at biology projects giving evidence of “purpose and agency” in organisms. For example, one grant given to a group of investigators, titled “Agency, directionality, and foundations for a science of purpose,” handed out more than $14.6 million! And one of the few areas in biology they’re funding again next year is, yes, projects on the “science of purpose”, to wit:

Science of purpose. We are looking for experimental and theoretical research projects that will provide insight into the purposive, goal-directed, or agential behaviors that characterize organisms and various components of living systems. Researchers who have familiarity with our ongoing work in this area are especially encouraged to apply.

Now you can easily see how this fits into the JTF’s original aim, which was to find evidence for divinity and spirituality in science. And indeed, I’m sure that’s why they’re funding this area.  But I’ve already argued that the only kind of “purpose” found in organismal behavior is that involved in conscious cogitation, which is present in only a few organisms.  Yes, some behaviors look “purposeful,” as when a bacterium moves toward or away from light, but that’s a purely mechanical response—not the kind that, say, humans have when they decide, “I’m going out for pizza.” And of course there is no goal-directedness or purpose in evolution, which simply sorts out genetic variation based on whether genes leave more or fewer copies of themselves, often leaving more when they adapt their carrier better to the environment.

However, the biologists who get funded for work on “agency” and “purpose” will be the first to tell you that they are not really imputing to organisms the kind of mental “purpose” that some organisms have, nor are they looking for anything numinous or supernatural. Rather, they seem to be whipping up a bunch of word salad that makes it seem that they are overthrowing the neo-Darwinian view that adaptations arise from genetic variants sorted out by their relative contribution to the genes of descendants.  Such researchers pretend that they are making profound new statements about biology and evolution, but when you look at the papers carefully, as I did with one of the influential papers (below) that Templeton funded in its “purpose and agency” program, you find nothing new. In this case, a whole paper touting “purpose” is merely re-describing something known for a long time: organisms can evolve “norms”of reaction”. These are simply the plastic developmental programs that organisms evolve to respond to environmental changes, so that behavior, physiology, and appearance can change when conditions change. That superficially may look like “agency”, but there’s no “will” involved, and nothing beyond genes responding to environments.

The evolution of norms of reaction is not hard to understand. Take one familiar plastic response: mammals like cats that grow longer fur in the winter.  This is due simply to natural selection acting on the DNA to respond to cold temperature by growing thicker fur. And, of course, as we know from all the varieties of dogs and cats with more or less fur, artificial selection can do that, too. We needn’t think about “purpose” or “agency” when we see this, nor need we say, “one purpose of this trait is to keep the cat warm” or “the cat has agency to grow longer fur to keep in warm in winter.”  That kind of talk about “purpose” is only confusing, hiding what really happened during evolution: natural selection for flexible forms of development.

And there are gazillions of traits that you could say look as if organisms have such agency or purpose, but they are all the result of natural selection. If a goat loses its front legs in an accident, it may well eventually walk on its hind legs. To do that, a number of their bones, tendons, and muscles have to be reconfigured to allow adaptive locomotion. But this, too, is a result of evolved plasticity: in the past, injuries may have been common, and those individuals with genes that allowed their development to compensate for those injuries, thus allowing the sufferer to survive and reproduce, outcompeted individuals lacking genes giving their bodies the ability to cope with injuries.

This is nothing new in evolution; people have talked about plasticity and “norms of reaction” (how organisms change to cope with changes in the environment”) for ages, and there are even experiments showing that such coping is due to natural selection.  But authors like those of the paper below, funded by the JTF, gussy up an old concept by calling it “biological agency”, enabling them to get a ton of cash from the JTF.

I see the effort as intellectually confusing and, indeed, hubristic, because surely the authors know what they’re doing. In the next and final installment of this “agency” mishigass, I’ll highlight a paper that calls this kind of effort to task, showing that it really doesn’t show anything new. Yes, I get excited when new concepts and findings appear in biology and especially evolution, but this ain’t one of them.

Click on the headline below to read the paper, which is free (there’s a pdf here):

The Sultan et al. paper is poorly written, full of big words that are supposed to constitute their idea of agency. But let’s see first how they define agency. Excerpts from the paper are indented.

What is agency? Sultan et al. assure us that it isn’t anything supernatural, but what it really is comes down to “self-regulation” that, in the end, simply amounts to the norms of reaction of an organism.

Living systems have evolved to be robust, responsive, flexible, self-synthesizing and self-regulating. This dynamic flexibility is manifest across diverse levels of biological organization, from cells, to tissues, to entire organisms, to reproductive lineages, to social colonies, and throughout a variety of organismal activities—from molecular signaling pathways to morphogenetic, metabolic, immune, endocrine, and behavioral systems. We use the term biological agency to refer to this suite of robust processes that is constitutive of living systems (See Box 1). Biological agency, in this sense, is the capacity of a system to participate in its own persistence, maintenance, and function by regulating its own structures and activities in response to the conditions it encounters.[69] Attributing agency to a biological system is based on natural, empirically determined processes and connotes neither consciousness nor deliberate intention.

or

Agency is a dynamical property of a system.[162] It consists in the system’s capacity to transduce, configure, and respond to the conditions it encounters. Crucially, agential systems are capable of maintaining functional stability in response to conditions that would otherwise compromise their viability.

Try as I might, I cannot see a distinction between this farrago of fancy words and good old “norms of reaction”.  “Self regulation” is simply the end result of natural selection acting on organisms so that when the environment changes, they respond through their evolved developmental systems in an adaptive way. Note that the authors explicitly rule out “purpose” of “deliberate intention” in the “consciousness” sense here.  Ergo, “maintaining functional stability in response to conditions that would otherwise compromise their viability” is just like a cat growing longer fur in the winter, but it sure is a fancy way of saying it.

Here some examples the authors adduce for “agency”:

Polypterus fish reared in a terrestrialized environment in which fish are forced to walk on their pectoral fins rather than swim, adjust—within a lifetime—not just their behavior, gait and posture but also their skeletal features, in ways that parallel the fossil record of tetrapods’ ascendance onto land.[136] Tadpoles exemplifying the ancestral detrivorous life style and associated gut morphology will adjust the latter if forced to consume a carnivorous diet, in ways that partly parallel evolved changes in specialized carnivorous lineages.[137] Examples such as these suggest that interactions between developmental systems and environmental circumstance may bias the production of phenotypic variation in the face of novel or stressful environments toward functional, integrated, and possibly adaptive variants.

No, the phenotypic direction isn’t “biased” by anything but natural selection. Polypterus fish live in shallow water and have lungs, and it’s possible that their ancestors evolved to walk on their fins to get around in that shallow water or even to leave the water for brief periods of time if their ponds are drying up and they need to get to another pool of water.  Or, it’s even possible that this norm of reaction isn’t evolved at all, but simply the result of an organism struggling to move when that’s the only alternative it has. Here’s what it looks like:

Try that with a goldfish! Why do Polypterus show “agency” in this way but not goldfish? Probably because of the evolutionary background of this species, which is sometimes regarded as an example of the kind of fish that evolved into terrestrial teterapods. But what “agency” are they showing? Likewise, it’s easy to see how tadpoles could occasionally encounter a situation in which there is more “meat” (other organisms or their remains) to eat than there is non-animal detritus. In that case, tadpoles able to evolve a way to change their digestion in such a circumstance would leave more offspring than those that couldn’t. Of course for this system to work, the environment would occasionally have to change in a way that would give organisms like this an advantage (it doesn’t have ot change every generation).  If organisms evolved a developmental system to adapt to environmental changes that couldn’t conceivably have occurred, then we’d have something to talk about! But I know of no such cases.

To justify their “new” approach, the authors give examples of three phenomena that, they say, can’t be explained by conventional neo-Darwinism:

1). Genome-wide association studies (GWAS), in which genes for traits are identified by looking at which genetic variation in an entire genome is correlated with variation in a trait, often reveal “too few genes”.  For example:

In the case of body weight, for example—a biomedically critical trait in the context of obesity, insulin resistance and type 2 diabetes—115 genetic loci that showed significant statistical association with body mass index (BMI) collectively explained less than 3% of the variation among adults,[8] and a meta-analysis based on an enormous sample of 700,000 individuals (conferring great statistical power) still explained only 6% of BMI variation[9] despite using a high-dimensional correlation matrix that is known to inflate these estimates.[10] While such extremely large studies may incrementally add to the variance explained by identifying additional loci of small effect through sheer statistical force, over 90% of (a) phenotypic variation for BMI and (b) risk of type 2 diabetes remains unaccounted for,[11, 12] pointing to a more fundamental issue.

And yet heritability studies, involving simple correlation of BMI between relatives is measured, show that between 40% and 70% of the variation of that trait among individuals is due to variation in genes. We can find only 6% of those genes, so where are the rest?  One explanation is that there are many genes affecting BMI whose effects are too small to be measured by GWAS, which requires pretty big effects to find a genetic region affecting a trait. Further, GWAS analyses rely entirely on SNPs (single nucleotide polymorphisms in DNA sequence), and are unable to detect duplications and deletions, which we know make a contribution to human trait variation (see references here, here, and here). Finally, GWAS is unable, except in vary large samples, to detect rare genes, and yet given the size of the genome, everyone has quite a few “rare” genes.  When you use large samples, as they have done for human height, the missing heritability diminishes to almost zero: the genetic variation detected by GWAS gives predictions that are almost the same as that based on standard heritability studies.

The authors add this:

Biomedical researchers concerned about the limits of the GWAS approach are therefore increasingly calling for conceptually broader studies directly addressing processing pathways that modulate gene function and hence phenotypic outcomes in individuals via complex gene-environment interactions,[18] environmentally-mediated epigenetic modifications,[19, 20] and physiological and developmental feedback systems such as microbiome composition, which changes dynamically in response to the individual’s diet, behavior, and social environment.[21]

Yes, perhaps there are some differences in microbiomes that are responsible here, but there are many traits where there are “missing genes” that cannot be imputed to microbiome inheritance. As for epigenetic modifications and the like beyond bacteria in the gut, those would also show up in GWAS studies, and so can’t constitute “missing genes” (an epigenetic modification occurs at a given site in the DNA, involves a modified base, and is supposedly inherited over at least one generation).

But much of the above is simply gobbledygook: how can “dynamic changes in response to diet, behavior, and social environment” account for missing genetic variation that shows up in heritability studies but not GWAS studies? This could occur only in species in which cultural, nongenetic factors are inherited, like the tendency to eat fatty foods. But these factors are usually ruled out in most heritability (e,g., in flies) and those studies still show a substantial genetic contribution to variation in a phenotype. What the authors consider “agency” here is not clear, but they are doing a service by highlighting a problem that has yet to be solved: “dark heritability.” We don’t know the answer yet, but we have some clues, and time will tell.

2). The authors drag in epigenetics to explain the missing heritability. This second problem is really the same as the first: we have a mismatch between results revealed by GWAS analysis and simple studies of heritability via correlation between relatives.  But this doesn’t solve the problem: it compounds it for two reasons. First, epigenetic modifications of DNA will show up in GWAS and heritability studies, and so don’t constitute “dark genetic variation”. Further, non-coding RNAs, which the authors further use to explain missing variation, are also inherited.  Finally, and most important, epigenetic modifications of DNA resulting solely from the environment (and not coded for themselves in the genome) almost never persist for more than two or three generations, and thus can’t explain a persistent appearance of “adaptive change” over evolution. Nor are epigenetic modifications usually adaptive, and they can be maladaptive (as in the “Dutch famine trauma”), because they are not evolved but simply the effect of the environment on a genome not adapted to changes in that environment.

Here is one example the authors use to show agency via purported epigenetic change:

An experimental example using isogenic plants points to part of what may be missing. In one series of experiments with the common herb Polygonum, parent plants of the same genetic line were either drought-stressed or given ample water. When their offspring were grown in identical, dry, conditions, they developed differently: the offspring of drought-stressed parents produced significantly larger and more rapidly-extending root systems than those of the moist-grown parents, an inherited phenotypic effect that resulted not from a genetic difference but in response to parental conditions.

“Isogenic” means that all the plants were genetically identical. And yes, it’s hard to imagine that offspring have a way of genetically “knowing” whether their parents experienced drought, though there could be cytoplasmic effects.  So this looks like agency, and may be due to adaptive epigenetic modification.  But this is the exception, rather than the rule.

3.) This is the kicker: neo-Darwinism cannot, say the authors, explain the origins of “novel, complex traits”. Here we have one of the assertions of intelligent design, but although there’s no designer, the authors’ claim about the impotence of neo-Darwinism in producing complex adaptations is simply wrong (they are implying, I think, that organisms are somehow using their AGENCY to develop those complex traits. Here’s the assertion:

The origin of novel complex traits constitutes a central yet largely unresolved challenge in evolutionary biology.[61] Ever since the founding of evolutionary biology one of the discipline’s core motivations has been to understand such elaborate innovations as the vertebrate eye, the insect wing, or the mammalian placenta, traits whose origins transformed the diversity of life on earth. Yet conventional approaches to understanding evolutionary change have provided few opportunities to make significant headway.[62] Of the four evolutionary processes conventionally recognized—natural selection, genetic drift, migration, and mutation, the first three can only sort among existing variants and their distribution within and among populations, but by themselves cannot bring about novel features.[63] This privilege is instead restricted to mutation, yet all attempts to explain the evolution of novel complex traits solely via the coincident origin, spread, and fixation of one beneficial mutation at a time have failed.

Sorry, but this resembles what comes out of the south end of a cow looking north. There is no conceptual reason that sorting out existing and new genetic variants via conventional natural selection is impotent to produce complex traits. The problem is that we simply weren’t there when many complex traits evolved, and so don’t know the genes involved, the selection pressures involved, or even the developmental pathways involved in producing the traits.

I know of only one attempt to get at this problem, and that involved the evolution of the camera eye. This was the work of Nilsson and Pelger summarized in a delightful summary by Richard Dawkins called “The eye in a twinkling“.  Using conservative (“pessimistic”) assumptions about mutation rates, heritabilities, and the number of developmental steps required to transform a light-sensitive spot into a complex “camera eye” with a lens, retina, and cornea (viz., what we and some cephalopoods have), Nilsson and Pelger found out that the evolution of this assuredly complex trait took around 400,000 generations. As Dawkins noted:

Assuming typical generation times of one year for small animals, the time needed for the evolution of the eye, far from stretching credulity with its vastness, turns out to be too short for geologists to measure. It is a geological blink.

And so it might be with other traits, like wings or placentas. The problem is making an appropriate model, and that is hard or impossible without knowing how the trait evolved (we have some idea with the eye, as Dawkins notes, hearkening back to Darwin, who first raised the “eye problem”.) But without such models, it’s almost deceitful to say that we need a new paradigm to explain the evolution of complex traits. (In fact, we can see the evolution of complex traits—like whales evolving from land ungulates in a mere 10,000 years. And that is surely due to selection, though we can’t say with assuredness that conventional neo-Darwinism was involved. But our ignorance does not justify us trying to depose a well-established paradigm, and one that works very quickly in the case of artificial selection (genetic analysis of adaptations invariably shows that changes in the DNA are involved).  Are dog breeds all due to epigenetic modifications of DNA or “agency” in the ancestral wolf? I don’t think so!)

I’ve already gone on too long, but if this paper is typical of the kind of research the JTF is funding as evidence for agency and purpose, it’s throwing its money down the toilet,.

Oh, and one last beef. When I saw this claim in the Sultan et al. paper, I was astonished:

In Maize, for instance, the “profound” architectural and reproductive changes that distinguish cultivated Maize from its wild progenitor, Teosinte, resulted not from novel mutants but from the response of a complex epistatic network to the atmospheric CO2 and crowded planting conditions encountered during the species’ early cultivation.[155]

What? This change, from the grass teosinte on the left to modern corn on the right (hybrid is in the middle) has nothing to do with novel mutations?

John Doebley, CC BY 2.5, via Wikimedia Commons

I looked up reference 155 and found this:

For example, genetic research shows that once-emphasized conventional assumptions about morphological change—e.g., that the change was driven mainly by human selection for rare mutants of a few single genes that were deleterious in wild plants and favorable in field environments or by selection for new, advantageous mutations that appeared postcultivation—have, for some major traits, been supplanted by different and/or more complex processes. These processes include (i) regulatory changes that targeted diverse developmental pathways and led to changes in gene expression (e.g., how, when, and to what degree existing genes are expressed through changes in the amount of mRNA during transcription); (ii) extensive rewiring of transcriptomic and coexpression networks; (iii) in an increasing number of wild progenitors, the presence and availability to the first cultivators of preexisting, nondeleterious genetic components for major domestication traits (known as “cryptic genetic variation”) that induce trait variation only under specific environmental or genetic conditions; and (iv) deviations from simple Mendelian expectations.

Every change mentioned involves mutations, whether they be structural, regulatory, or “cryptic” (genes showing their effects only under limited conditions). There is nothing new here, merely an explication of how artificial selection on teosinte involved a variety genetic changes.  There is NO AGENCY in teosinte, not even construed as broadly as Sultan et al. do.

In the end, the paper seems to be much ado about nothing, which, in the last chapter (maybe tomorrow) another author will analyze critically, showing that there’s no “there” there.

I know many people won’t be interested in this analysis, but I wanted to get it on the record because so many people are hearing that not only is neo-Darwinism a pretty useless paradigm for understanding adaptation, but now are hearing as well that some nebulous “purpose” and “agency” are involved. As usual, Templeton’s money has only muddied the water.

 

h/t: Luana for her explanations of GWAS.

Most of the neutron stars we know of have a mass between 1.4 and 2.0 Suns. The upper limit makes sense, since, beyond about two solar masses, a neutron star would collapse to become a black hole. The lower limit also makes sense given the mass of white dwarfs. While neutron stars defy gravitational collapse thanks to the pressure between neutrons, white dwarfs defy gravity thanks to electron pressure. As first discovered by Subrahmanyan Chandrasekhar in 1930, white dwarfs can only support themselves up to what is now known as the Chandrasekhar Limit, or 1.4 solar masses. So it’s easy to assume that a neutron star must have at least that much mass. Otherwise, collapse would stop at a white dwarf. But that isn’t necessarily true.

It is true that under simple hydrostatic collapse, anything under 1.4 solar masses would remain a white dwarf. But larger stars don’t simply run out of fuel and collapse. They undergo cataclysmic explosions as a supernova. If such an explosion were to squeeze the central core rapidly, you might have a core of neutron matter with less than 1.4 solar masses. The question is whether it could be stable as a small neutron star. That depends on how neutron matter holds together, which is described by its equation of state.

Neutron star matter is governed by the Tolman–Oppenheimer–Volkoff, which is a complex relativistic equation based on certain assumed parameters. Using the best data we currently have, the TOV equation of state puts an upper mass limit for a neutron star at 2.17 solar masses and a lower mass limit around 1.1 solar masses. If you tweak the parameters to the most extreme values allowed by observation, the lower limit can drop to 0.4 solar masses. If we can observe low-mass neutron stars, it would further constrain the TOV parameters and improve our understanding of neutron stars. This is the focus of a new study on the arXiv.

Previous searches for low-mass neutron stars. Credit: Kacanja & Nitz

The study looks at data from the third observing run of the Virgo and Advanced LIGO gravitational wave observatories. While most of the observed events are the mergers of stellar-mass black holes, the observatories can also capture mergers between two neutron stars or a neutron star and a black hole companion. The signal strength of these smaller mergers is so close to the noise level of the gravitational wave detectors that you need to have an idea of the type of signal you’re looking for to find it. For neutron star mergers, this is complicated by the fact that neutron stars are sensitive to tidal deformations. These deformations would shift the “chirp” of the merger signal, and the smaller the neutron star, the greater the deformation.

So the team simulated how sub-white-dwarf mass neutron stars would tidally deform as they merge, then calculated how that would affect the observed gravitational chirp. They then looked for these kinds of chirps in the data of the third observation run. While the team found no evidence for small-mass neutron stars, they were able to place an upper limit on the hypothetical rate of such mergers. Essentially, they found that there can be no more than 2,000 observable mergers involving a neutron star up to 70% of the Sun’s mass. While that might not seem like much of a limit, it’s important to remember that we are still in the early stages of gravitational wave astronomy. In the coming decades, we will have more sensitive gravitational telescopes, which will either discover small neutron stars or prove that they can’t exist.

Reference: Kacanja, Keisi, and Alexander H. Nitz. “A Search for Low-Mass Neutron Stars in the Third Observing Run of Advanced LIGO and Virgo.” arXiv preprint arXiv:2412.05369 (2024).

The post Neutron Stars With Less Mass Than A White Dwarf Might Exist, and LIGO and Virgo Could Find Them appeared first on Universe Today.