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The second-ever commercial landing on the moon comes amid a flurry of lunar exploration activity that will see around a dozen missions this year alone

Measles is back, and so are all the old antivax tropes about the disease and the vaccine. Unfortunately, there's an antivaxxer in charge.

The post Measles is back, and so are all the old antivax tropes about it first appeared on Science-Based Medicine.

There are several well-documented health risks that come from spending extended periods in microgravity, including muscle atrophy, bone density loss, and changes to organ function and health. In addition, astronauts have reported symptoms of immune dysfunction, including skin rashes and other inflammatory conditions. According to a new study, these issues could be due to the extremely sterile environment inside spacecraft and the International Space Station (ISS). Their results suggest that more microbes could help improve human health in space.

The study was led by Rodolfo A. Salido and Haoqi Nina Zhao, a bioengineer and an environmental analytical chemist at the University of California San Diego (UCSD), respectively. They were joined by researchers from multiple UCSD programs and centers, the University of Denver, the Chiba University-UC San Diego Center for Mucosal Immunology Allergy and Vaccines (cMAV), Space Research Within Reach, the Baylor College Center for Space Medicine, the Blue Marble Space Institute of Science (BMSIS), the Biotechnology and Planetary Protection Group at NASA JPL, and the Astronaut Office at NASA Johnson.

The study was a collaborative effort with astronauts aboard the ISS, who swabbed 803 different surfaces – 100 times that of previous surveys – to get a census of microbes aboard the station. The researchers identified which bacterial species and chemicals were present in each sample and created three-dimensional maps to illustrate where each of them was found and how they might be interacting. Their results indicate that the ISS has a much lower diversity of microbes compared to human-built environments on Earth.

NASA astronaut Catherine (Cady) Coleman, Expedition 26 flight engineer, is pictured with a stowage container and its contents in the Harmony node of the International Space Station. Credit: NASA

Overall, the team found that chemicals from cleaning products and disinfectants were ubiquitously throughout the station and that astronauts mostly introduce microbes aboard the ISS through shed human skin cells. They also found that different modules hosted different microbial communities and chemical signatures based on the module’s use. For example, dining and food preparation areas contained more food-related microbes, whereas the ISS’s space toilet contained more urine- and fecal matter-related microbes and bioproducts of metabolism (metabolites).

“We noticed that the abundance of disinfectant on the surface of the International Space Station is highly correlated with the microbiome diversity at different locations on the space station,” said Zhao in a Cell Press release. These results suggest that more microbes from Earth could help improve astronaut health. Said Salido:

“Future built environments, including space stations, could benefit from intentionally fostering diverse microbial communities that better mimic the natural microbial exposures experienced on Earth, rather than relying on highly sanitized spaces. If we really want life to thrive outside Earth, we can’t just take a small branch of the tree of life and launch it into space and hope that it will work out. We need to start thinking about what other beneficial companions we should be sending with these astronauts to help them develop ecosystems that will be sustainable and beneficial for all.” 

The team found that microbial communities were less diverse aboard the ISS than most places on Earth, except where urban, industrialized, and isolated environments (i.e., hospitals) were concerned. They further found that ISS surfaces lacked free-living environmental microbes usually found in soil and water. Similar to the well-documented benefits gardening has for the human immune system, the researchers conclude that incorporating these microbes and their substrates into the ISS could improve astronaut health without sacrificing hygiene.

Astronauts on the International Space Station experience an orbital reboost. Credit: NASA/ESA

“There’s a big difference between exposure to healthy soil from gardening versus stewing in our own filth, which is kind of what happens if we’re in a strictly enclosed environment with no ongoing input of those healthy sources of microbes from the outside,” said co-author Robin Knight, a computational microbiologist and professor at UCSD and leader of the Knight Lab.

Looking to the future, the researchers hope to refine their analyses to detect potentially pathogenic microbes and how environmental metabolites could be used as indicators for astronaut health. The team claims that these methods could also help improve the health of people living and working in similarly sterile environments on Earth.

This research was supported by the National Institute of Health (NIH), the Alfred P. Sloan Foundation, UCSD, the Center for the Advancement of Science in Space (CASIS), and the ISS National Laboratory. The paper detailing their findings, “The International Space Station has a unique and extreme microbial and chemical environment driven by use patterns,” was published on February 27th in the journal Cell.

Further Reading: EurekAlert!

The post For the Sake of Astronaut Health, Should we Make the ISS Dirtier? appeared first on Universe Today.

I guess the number of papers and articles people send me about the definition of sex is one sign that it remains an important issue for the populace.  Indeed, I think that in future decades people will see the kerfuffle about a simple and widely accepted definition (the gametic one) as a tempest in a teapot, stirred up by activists who demand that nature conform to their own ideology.

Philosopher Alex Byrne of MIT, whose recent book Trouble with Gender: Sex Facts, Gender Fictions I recommend, has also written a short and useful article on the site Fairer Disputations (“Sex-Realist Feminism for the 21st Century”) that covers a lot of ground, including the recent definition of sex given by the Department of Health and Human Services, the history of the definition that was used (the gametic one), the opposition to that definition, and “the British gender wars”, which are particularly nasty but have some smart combatants, like Helen Joyce, Emma Hilton, and J. K. Rowling, to defend those women who lose their jobs or get demonized for speaking the truth.

You can (and should) read Alex’s article by clicking below (it’s free), and I’ll give a few quotes (indented)

The beginning of understanding the nature of biological sex. Nobody really knew about gametes until 1677, when the Dutch scientist Antonie van Leeuwenhoek found little wiggly “animalcules” in his sperm.  Over the years since then, biologists began to realize that all animals and plants have two sexes with different gametes, and those gametes must usually unite to produce to produce a new offspring.  Further, regardless of whether the sexes are produced by chromosomes, the environment, genes, or social interactions, they are always two, and this condition has evolved independently nearly a dozen times. Here’s Alex’s description of the beginning, and how the definition continues–up to this day:

Sexual reproduction remained something of a mystery for the next five millennia, until the German physician Theodor von Bischoff hypothesized in the mid-nineteenth century that it involved the fusion of (in the EO’s language) two “reproductive cells”—one sperm and one ovum, or egg. The sperm is small and relatively simple, the egg large and much more complicated. When von Bischoff’s theory was later confirmed, it was a short step to uncovering the deep distinction between females and males: females produce large reproductive cells (or gametes), males produce small ones. What about producing both? Some animals (and many plants) do just that: they are hermaphrodites—female and male.

Here’s Robert Payne Bigelow, a biology professor from my own university, writing in 1903:

The ability to produce a macro- or microgamete constitutes the essential distinction of sex. The individual which produces the latter is said to be of the male sex, the individual producing the former is said to be of the female sex. In most of the higher plants and in a few of the lower animals both sexes are included in a single individual, which is then said to be hermaphrodite.

The French philosopher Simone de Beauvoir noted that the sexes are “defined primarily … by the gametes which they produce—sperms and eggs respectively” in The Second Sex, published in 1949. Yet in her 2023 book Beyond the Binary: Thinking About Sex and Gender, the feminist philosopher Shannon Dea tells us that “papaya trees come in three sexes—male, female, and hermaphroditic.” That is wrong, as Bigelow made clear 120 years earlier. Hermaphroditic papaya trees are both male and female, not a third sex.

The misguided critics. I can’t resist quoting this part, but the article has far more stuff in it:

In short, the EO’s [Executive Order’s] definitions of “female” and “male” are right, or at least substantially on the right lines. (On February 19, the Department of Health and Human Services issued a memo with improved versions.) So why the furor? What were the experts’ main complaints?

Some struggled with reading comprehension. The Director of the Centre for Indigenous Initiatives at Carleton University criticized the claim that there are “two genders” as “ignorant,” evidently thinking of so-called “third genders” in some traditional North American societies. But the EO pronounces on the number of sexes, not on the special cultural arrangements that have sometimes been made to accommodate homosexual men. In any case, even if the EO had said there were only two “genders,” it would have used the word as a synonym for “sex.”

Others were just painfully muddled. A biological anthropologist at the University of Urbana-Champaign declared that sex has multiple definitions, each valid for different purposes. One definition “is around typical hormone ranges. [For instance, people with] polycystic ovary syndrome end up having androgen levels that are very different from those of most people that we might put in the sex category of female.” The suggestion seemed to be that on one acceptable definition of “female,” people with polycystic ovary syndrome aren’t female because they have (relatively) high androgen levels. (The clue is in the name: polycystic ovary syndrome.)

Any acceptable definition of sex needs to get the right results for cats, ibises, and date palms, and one based on circulating hormones won’t. A definition based on chromosomes works for cats and date palms: they both employ the XX/XY sex determination system, with the males being XY. But ibises have it the other way round: the lady ibis is the one with different sex chromosomes. And what about other animals known to the ancient Egyptians, such as the Nile crocodile and the honeybee? The sex of a baby croc is determined not by chromosomes, but by the temperature of the nest, and male bees develop from unfertilized eggs, with half a set of chromosomes.

There is no definition of sex other than the standard gamete one that classifies female humans, cats, ibises, date palms, crocodiles, and bees correctly. That did not stop the anthropologist from saying that the EO “misunderstand[s] basic human biology.”

Anthropologists can be flaky. Still, one might have expected the Presidents of the Society for the Study of Evolution, the American Society of Naturalists, and the Society of Systematic Biologists to get basic biology right. However, according to them, in a letter to Trump and members of Congress, sex is a spectrum, a “continuum of male to female.” This “continuum” apparently has something to do with “chromosomes, hormonal balances, … gonads, external genitalia,” although the three presidents declined to spell out the details. Presumably, on this account, women with polycystic ovary syndrome are mostly-but-not-entirely female—perhaps a slight improvement on the anthropologist’s position. The biologist Jerry Coyne dissected the letter on his blog, writing in an email, “I used to be President of the Society for the Study of Evolution. Now it embarrasses me.”

And I’ll add that while most of the evolutionists I know agree about the gametic definition of sex, there is of course still debate about how that definition will be used on documents, driver’s licenses, and the like. Alex recognizes that these issues are far more contentious—at least to biologists:

Trump’s EO does not rest with the biological facts; it also sets a raft of policies. Among other things, government officials are directed “to require that government-issued identification documents, including passports, visas, and Global Entry cards, accurately reflect the holder’s sex.” It is understandable that someone seeking peace of mind by living as a member of the other sex would want a sex marker to match, especially when traveling to the less tolerant parts of the world. We should hope that the EO does not make life more difficult for such people than it already is. That hope is undoubtedly in vain, but the problem with pushing the pendulum too far in one direction is that it will tend to swing too far in the other. The activists who—predictably—have produced an equal and opposite reaction have only themselves to blame.

Here we have a new paper in Nature Scientific Reports, accompanied by a news piece in Science, that sends a misleading message to the public, both about “inheritance of trauma” and the effects of epigenetic changes.  Both pieces are free to access; click on the first headline below to go to the news piece, and the second to go to the scientific report (its pdf is here). 

I must add that most of the “misleading” appears not in the paper but in the News piece by Andrew Curry, who suggests that trauma is inherited when in fact there’s not a scintilla of evidence for that. But the authors of the real paper don’t go to any great lengths to dispel that notion, either, and this suggestion is undoubtedly why Nature Scientific Reports found the piece clickbaity and publishable.

Note that the news piece suggests that what is inherited across three generations is trauma. That is false. What the researchers shows is that Syrian women exposed to trauma during their country’s wars have offspring and grand-offspring that inherited certain epigenetic markers in the DNA: methyl groups affixed to consistent positions in the offspring DNA.  This “epigenetic inheritance” may indeed be caused by maternal trauma, for trauma messes up the fetal environment, and since female fetuses already carry their own eggs after a few months, it could affect grandchildren at all.

But inheritance of trauma itself? NO EVIDENCE. They have no idea what the DNA positions that are methylated even do, much less that they’re in genes that affect trauma.

The situation described in both the news puffery and the paper resembles the “epigenetic” inheritance associated with the Dutch “Hunger Winter” of 1944-1945, during which a German blockade of food killed around 20,000 people in the Netherlands.  It turns out that the children of survivors who were pregnant during the famine had a higher frequency obesity, higher cholesterol, as well as higher incidences of diabetes and schizophrenia, than did children of survivors who were not pregnant. The former also lived less long, but what they inherited as not “famine”, but a panoply of diseases and conditions that may well have been the result of biochemical changes in a pregnant mother experiencing famine. These changes were certainly not adaptive, either!  However, the inheritance lasted only one generation (grandchildren of pregnant survivors were normal). PLUS, what was inherited in the famous Dutch case were conditions and behaviors, while in the present case the “trauma” appears to have caused only slight changes in the DNA sequence that had an unknown effect. There was no inheritance of trauma described at all. But look at the headline below!

The news piece:

It summarizes the scientific report this way:

Rana Dajani, a biologist at Hashemite University in Amman, Jordan, wondered whether the recent conflicts in neighboring Syria might have left traces in the epigenomes of people in the country—with implications for the health of future generations. “I wanted to ask if environmental exposure was impacting different genes,” Dajani says. “Can those changes be transferred across three generations, or more?”

To answer that, Dajani, a Jordanian researcher of Palestinian and Syrian descent, teamed up with researchers in the United States and Jordan, leveraging her family contacts to assemble a cohort of Syrian women living in Jordan. In one group were women and girls who were either pregnant or in utero themselves during the Syrian civil war that began in 2011 and had fled to Jordan. Another group included someone who was pregnant during a government-orchestrated massacre in the city of Hama in the early 1980s, her daughter and grandchildren, and other unrelated female descendants of survivors. As a control group, Dajani included Syrian families who emigrated to Jordan almost a century ago, sharing a culture with the rest of the participants but with no direct experience of violent conflict.

Biologist Dima Hamadmad, a co-author and a descendant of survivors of the Hama violence, spent hundreds of hours over the course of 5 years contacting potential participants and listening to their stories. Many of them had experienced trauma such as being severely beaten, witnessing wounded or dead bodies, or seeing someone being shot or killed. “It’s a lot of work, and the victims also deserve a lot of credit,” says Isabelle Mansuy, an epigeneticist at ETH Zürich who was not part of the research. “What they’ve done is remarkable.”

After using cheek swabs to collect DNA from more than 130 women, the team looked for patterns in DNA methylation, a process in which responses to environmental circumstances—such as trauma—add or subtract to genes chemical tags known as methyl groups that alter the gene’s function. DNA methylation is among the most studied examples of epigenetic change.

The team found that women who experienced wartime trauma directly shared such changes in 21 different spots in their genome; grandchildren in the study showed alterations in a different set of 14 sites. “We discovered a number of genes with signatures of trauma transferred across generations compared to the control group,” Dajani says. The function of the genes and proteins associated with the sites isn’t known.

Comparing those results with the surveys and interviews revealed the more wartime horrors someone experienced, the more methylation changes they seemed to have. “It doesn’t look random,” says Mulligan, who co-led the study with Dajani.

I’m prepared to believe all that, though I’m disturbed by the important control group, which is described as “Syrian families who emigrated to Jordan almost a century ago, sharing a culture with the rest of the participants but with no direct experience of violent conflict.” Well, one can debate whether a group that has been in non-warring Jordan for a century has experienced the same “culture” as Syrians who emigrated in 1980 and 2011. But others who know more about epigenetics than I have weighed in with other criticisms (see below). What was affected may not have been trauma, but just gum disease!

Click the article to read. I can’t find any description of the control group in the paper except for this—”In the control group, Syrian grandmothers and mothers lived in Jordan prior to 1980″, and it adds they were “unexposed to war,” but it doesn’t say that not that the ancestors of the control individuals been in Jordan for a century. Oh well, we’ll let that slide.

The paper:

Here’s a diagram of the experimental setup from the paper; the caption is also from the paper. Click to enlarge.

There are three groups: the control (right), consisting of pregnant women unexposed to war; the 1980 group, which included women who experienced violence when the fetuses had eggs (about 12 weeks into pregnancy); and the 2011 group, which included women who experienced violence in the early stages of pregnancy, before the (female) fetus developed eggs. Click diagram to enlarge:

(From paper): Our research strategy was designed to test contrasting exposures to violence (direct, prenatal, germline) for changes in DNAm in three groups of three-generation Syrian families. The violence exposures of three generations (F1, F2, F3) for each group are indicated—the 1980 group was directly, prenatally, and germline exposed in the F1 generation, the 2011 group was directly and prenatally exposed in the F2 generation, and the Control group was unexposed. Exposure types are color coded: red = direct exposure, green = prenatal exposure, blue = germline exposure, and yellow = no exposure.

Note the very small sample size of both women exposed to trauma and their children and grandchildren. Here is the violence the authors describe what was experienced by pregnant women:

“. . . . violent traumatic experiences that included being severely beaten, being persecuted (by the authorities/militia), seeing a wounded or dead body, and seeing someone else severely beaten, shot or killed.”

They then did DNA sequencing of all individuals using a sampling system that identified 850,000 nucleotide bases (SNPs). Out of these, they found 21 sites that were methylated in a pretty consistent way among those who experienced violence; these were in the pregnant women’s non-germline DNA, so could not be passed on. However, they found another 14 sites  methylated in the germline (mother’s or fetus’s eggs), and were inherited across not just one generation, but across two (this might be expected since fetal eggs can also be exposed to grandmother’s physiological conditions).  But in no case did they know which genes were involved in the changes, though they speculate that some regions could be involved in “gene regulation”.

The authors conclude this:

There is strong scientific evidence indicating that impacts of stress and trauma can reverberate far into the future, possibly through epigenetic mechanisms.

Well, that’s true if “far into the future” means “three generations,” but epigenetic marks are usually wiped clean from the DNA when gametes (sperm and eggs) are made, and four generations is about as far as any environmental alterations of mammalian DNA have persisted. What we do not have here is either inheritance of trauma or any kind of permanent evolutionary change produced by the environment. This is manifestly not “Lamarckian inheritance“!

The news piece does proffer some mild criticism:

These results are consistent with research in mice and other organisms that shows trauma can be passed down across generations. But other researchers note that the sample size isn’t big enough to confidently conclude that trauma passes from generation to generation through the germline—in this case via egg cells. “It’s important to do studies like this, and we need more of them, and with larger samples,” says Michael Pluess, a psychologist at the University of Surrey who was not involved in this study but whose own work with Syrian refugee children has found similar violence-related methylation changes in different places of the genome. “We also need to replicate the findings to know if they’re real or just chance.”

If you click on the first link in the preceding paragraph, you’ll find changes in biomarkers that may be associated with trauma in humans and mice, but not evidence for the inheritance of trauma itself.

But there is even stronger criticism of the methods and conclusions posted on Bluesky by John Greally, a professor of genetics at Albert Einstein College of Medicine, and he has  the chops to criticize.  Here’s his post thread in its entirety. One of his important criticisms appears to be that they got the Syrian DNA by using buccal (cheek) swabs, and, as Greally notes, “This could be a very expensive study of gingivitis.” Also, note the penultimate post in which Greally says that there’s not any convincing evidence (including this paper) for transmission of acquired characteristics in mammals.”  Just remember that when you hear about this study or the famous but misleading Dutch famine study.

 

As I wrote on February 13, three important societies representing evolutionary biology, ecology, and systematics issued a grossly misleading statement aimed at the government. (It is dated February 5, but I don’t think it’s yet been sent):

As I reported recently, the Presidents of three organismal-biology societies, the Society for the Study of Evolution (SSE), the American Society of Naturalists (ASN) and the Society of Systematic Biologists (SSB) sent a declaration addressed to President Trump and all the members of Congress. (declaration archived here)  Implicitly claiming that its sentiments were endorsed by the 3500 members of the societies, the declaration also declared that there is a scientific consensus on the definition of sex, and the consensus is that sex is not binary but rather some unspecified but multivariate combination of different traits, a definition that makes sex a continuum or spectrum—and in all species! The bolding below is Jerry’s:

Scientific consensus defines sex in humans as a biological construct that relies on a combination of chromosomes, hormonal balances, and the resulting expression of gonads, external genitalia and secondary sex characteristics. There is variation in all these biological attributes that make up sex. Accordingly, sex (and gendered expression) is not a binary trait. While some aspects of sex are bimodal, variation along the continuum of male to female is well documented in humans through hundreds of scientific articles. Such variation is observed at both the genetic level and at the individual level (including hormone levels, secondary sexual characteristics, as well as genital morphology). Beyond the incorrect claim that science backs up a simple binary definition of sex, the lived experience of people clearly demonstrates that the genetic composition at conception does not define one’s identity. Rather, sex and gender result from the interplay of genetics and environment. Such diversity is a hallmark of biological species, including humans.

And as I write this today, I am still baffled how the different traits are supposed to be combined to determine one’s sex. I’d also like to ask the three societies exactly how many human sexes there are. As I’ve said before, I’m embarrassed to have been associated with the SSE since it’s now rejecting science in favor of currying favor with “progressive” ideology. It’s okay for societies to respond to situations that fall within their ambit, as this case does, but it’s not okay for them to purvey bogus science to buttress a political position.

Our original letter included 23 signers, most of whom are included in this second and final version of the letter.  The first letter never received a response (I find that rather rude), but we’re hoping for a response to this one.

The list of signers has now grown to 125, whose names are placed below the fold to keep this post shorter. If we’ve counted correctly, the signers come from nineteen countries. (We have omitted the names of five medical doctors and a nurse who also signed.) Every signer was willing to make their names public—a condition for signing the group letter. Others I know of have written privately to the Presidents of the Societies—and received a response, so the Societies clearly didn’t think they had to respond to our first letter.

The point of this letter is not to show that our view is a “consensus” (the Societies did not poll their members, either), but simply to affirm that a variety of people in biology or adjacent areas reject the Societies’ construal of sex as both a “construct” and a “spectrum”.  The letter below speaks for itself.

By the way, the driving force for writing the letter and collecting the signatures was Luana Maroja, Professor of Biology at Williams College, so kudos to her. And below this line is our letter, which was sent to the societies four minutes before this posting.

Dear presidents of the Tri-societies: ASN, SSB and SSE,

We, Tri-society members and/or biologists, are deeply disappointed by your recent letter “Letter to the US President and Congress on the Scientific Understanding of Sex and Gender” issued last Wednesday, Feb 5, 2025, in response to Trump’s executive order “Defending Women From Gender Ideology Extremism And Restoring Biological Truth To The Federal Government”.

While we agree that Trump’s executive orders are misleading, we disagree with your statements about the sex binary and its definition. In animals and plants, binary sex is universally defined by gamete type, even though sexes vary in how they are developmentally determined and phenotypically identified across taxa. Thus, your letter misrepresents the scientific understanding of many members of the Tri-societies.

You state that: “Scientific consensus defines sex in humans as a biological construct that relies on a combination of chromosomes, hormonal balances, and the resulting expression of gonads, external genitalia, and secondary sex characteristics.”

However, we do not see sex as a “construct” and we do not see other mentioned human-specific characteristics, such as “lived experiences” or “[phenotypic] variation along the continuum of male to female”, as having anything to do with the biological definition of sex. While we humans might be unique in having gender identities and certain types of sexual dimorphism, sex applies to us just as it applies to dragonflies, butterflies, or fish – there is no human exceptionalism.   Yes, there are developmental pathologies that cause sterility and there are variations in phenotypic traits related to sexual dimorphism. However, the existence of this variation does not make sex any less binary or more complex, because what defines sex is not a combination of chromosomes or hormonal balances or external genitalia and secondary sex characteristics. The universal biological definition of sex is gamete size.

If you and the signers of this letter do not agree on these points, then the Tri-societies were wrong to speak in our names and claim that there is a scientific consensus without even conducting a survey of society members to see if such a consensus exists. Distorting reality to comply with ideology and using a misleading claim of consensus to give a veneer of scientific authority to your statement does more harm than just misrepresenting our views: it also weakens public trust in science, which has declined rapidly in the last few years. Because of this, scientific societies should stay away from politics as much as possible, except for political issues that directly affect the mission of the society.

Respectfully,

NAMES OF 125 SIGNERS ARE BELOW THE FOLD

[Click “continue reading” to see the names.]

In alphabetical order:

Charleen Adams, Lead Statistical Geneticist, Beth Israel Deaconess Medical Center

Eli Vieira Araujo-Jnr, biologist and independent journalist, Brazil

John Avise, Emeritus Professor, Univ, of California, Irvine

Nick Bailey, Research Fellow in Bioinformatics

Daniel A. Barbash, Professor, Molecular Biology and Genetics, Cornell University

Alexander T. Baugh, Associate Professor, Department of Biology, Swarthmore College

David Bertioli, Distinguished Investigator and Professor, College of Agricultural and Environmental Sciences, University of Georgia, USA

Andreas Bikfalvi, Professor MD PhD, University of Bordeaux, France

Franco Biondi, Professor of Natural Resources and Environmental Science

Ranieri Bizzarri, Professor of Biochemistry, University of Pisa, Italy

William J. Boecklen, Professor, Department of Biology, New Mexico State University

Jacobus (Koos) Boomsma, Emeritus Professor, University of Copenhagen Department of Biology

Glenn Borchardt, Director, Progressive Science Institute

Gary Bowering, Member, Royal Society of New Zealand

Gordon M. Burghardt, Professor of Psychology and Ecology & Evolutionary Biology (Emeritus), University of Tennessee

Chris Campbell, Research Assistant Professor (retired)/ University at Buffalo

Joseph Ciccolini, Professor/University Hospital of Marseille France

Kendall Clements, Professor, School of Biological Sciences, University of Auckland

Mark Collard, Chair in Human Evolutionary Studies, Simon Fraser University

Michael Coon, Scientist/Biopharma (cell therapy)

Athel Cornish-Bowden, Directeur de Recherche Émérite au CNRS (retired)

Richard Cowling, Emeritus Professor of Botany, Nelson Mandela University

Jerry Coyne, Professor Emeritus, Ecology and Evolution, University of Chicago

David Curtis, Honorary Professor, Genetics Institute, University College London, UK

Richard Dawkins, Emeritus Professor, University of Oxford

Robert O. Deaner, Professor, Department of Psychology, Grand Valley State University; PhD Biological Anthropology & Anatomy, Duke University

Gilly Denham, SSE member, Williams College

Lynn Devenport, Professor Emeritus of Psychology, University of Oklahoma

Chet Dickson, Secondary Education (retired)

Paul Doerder, Professor Emeritus Cleveland State University

Gavin Douglas, Postdoctoral Researcher, North Carolina State University

Janet Roman Dreyer, Retired PhD Research Fellow Caltech

Joan Edwards, Samuel Fessenden Clarke Professor of Biology, Williams College

Nelson Jurandi Rosa Fagundes, Associate Professor, Department of Genetics, Federal University of Rio Grande do Sul

Lars Figenschou, PhD. The Arctic University of Norway

David Frayer, Prof. Emeritus – Anthropology, University of Kansas

Steven M. Fredman, Associate Professor of Physiology & Neuroscience (retired)

Jonathan Gallant, Professor Emeritus of Genome Sciences, University of Washington

Constantino Macías Garcia, Full-time researcher (professor), Instituto de Ecología, Universidad Nacional Autónoma de México (UNAM)

Brian Gill, retired natural history curator from Auckland Museum, New Zealand

David Greene, Professor, California State Polytechnic University, Humboldt

Christy Hammer, Associate Professor of Education, Sociology, and Women and Gender Studies, University of Southern Maine

Brian Hanley, Biologist, PhD. UC Davis

Sheila Rutledge Harding, Professor (ret’d), College of Medicine, University of Saskatchewan

Michael Hart, Professor, Simon Fraser University

Wesley Hawthornthwaite, BSc Neuroscience and Mental Health, Carleton University

James Heard, MS Biology, San Francisco State, SF, California, Retired

Jody Hey, Professor, Temple University

Emma Hilton, Developmental Biology, University of Manchester, U.K.

Susan Hoffman, Associate Professor of Biology, Miami University and 40 year member of SSE

Carole Kennedy Hooven, Senior Fellow, AEI; Affiliate, Harvard Psychology.

David Hughes, Teaching Fellow in Marine Biology (retired), Scottish Association for Marine Science

Peter M. Hurley, PHD Widlife Biologist, currently GIS Analyst, Grant County, NM

Christine Janis, Professor Emerita, Ecology, Evolution, and Organismal Biology, Brown University

Maria Garza Jinich, Retired CS professor. National University of Mexico.

Brian Jones, Retired Principal Fish Pathologist, Government of Western Australia

Robert King, Dr, University College Cork, Ireland

Anatoly Kolomeisky, Professor of Chemistry, Rice University

Shawn R. Kuchta, Professor, Biological Sciences, Ohio University

Michael Lattorff, Associate Professor (Parasitology) / University of KwaZulu-Natal, School of Life Sciences, Durban, South Africa

Benoît Leblanc, Lecturer, Sherbrooke University

Edward Lee, SSE member, Williams College

Harry Lusic, Associate Professor of Chemistry, William Peace University

Dan Lynch, Professor of Biology, Emeritus, Williams College

Maya Dyankova Markova, Associate Professor of Biology at the Medical University of Sofia, Bulgaria

Luana S. Maroja, Professor of Biology, Williams College

Edward Matalka, SSE member, Adjunct Professor of Biology, Worcester State University

Nicholas J. Matzke, Senior Lecturer, School of Biological Sciences, University of Auckland

Gregory C. Mayer, Professor of Biological Sciences, University of Wisconsin-Parkside

Stephanie Mayer, Senior Instructor Emerita, Department of Ecology and Evolutionary Biology, University of Colorado, Boulder

Marcella McClure, Microbiology retired from Montana State University

Richard J. McNally, Professor of Psychology, Harvard University

Axel Meyer, Lehrstuhl für Zoologie und Evolutionsbiologie, University of Konstanz

William Meyer, Educator, General Science, Mokena Junior High School, Illinois

Neil Millar, Biology textbook author and retired biology teacher

Michael Mills, Associate Professor of Psychology, Loyola Marymount University

Graeme Minto, Biologist, Πανεπεστιμιο Κριτις

Robert Montgomerie, Professor Emeritus of Biology Queen’s University

Greg Murray, Professor Emeritus of Biology, Hope College

Paulo Nadanovsky, Professor of Epidemiology, Universidade do Estado do Rio de Janeiro

Raymond Nelson, Biology Educator/North Thurston Public Schools

Howard S. Neufeld, Professor of Biology, Appalachian State University

Judith Totman Parrish, Professor and Dean Emerita/University of Idaho

Laurent Penet, PI in Agricultural Science, INRAe, Guadeloupe

Charles C. Peterson, Ph.D., Retired biologist Copper Mountain College

Steven Pinker, Johnstone Family Professor of Psychology, Harvard University

David Policansky, PhD, Scholar, US National Research Council, retired.

Chris Pook, Senior Research Fellow; Lead Technologist, The Liggins Institute, The University of Auckland

Anthony M. Poole, Professor, School of Biological Sciences, University of Auckland

Jorge Octavio Juarez Ramirez, PhD Candidate (Biological Sciences, Evolution and Genetics)/Universidad Nacional Autonoma de Mexico

Mary Rasmussen, Professor Emerita, Biomedical and Health Information Sciences, University of Illinois Chicago

Michel Raymond, Evolutionary Anthropology, Institute of Evolutionary Studies, Montpellier, France

Jaime Renart, Retired researcher, molecular and cellular biology, CSIC. Spain

Jacques Robert, Emeritus professor of cancer biology, University of Bordeaux, France

Mel Robertson, Professor Emeritus of Biology, Queen’s University at Kingston, ON, Canada

Rafael L. Rodriguez, Professor, Biological Sciences, University of Wisconsin-Milwaukee

James J. Roper, Professor (retired), ecology, evolution, ornithology, Institute for Tropical Ecology, Panama

Callum Ross, Professor of Organismal Biology and Anatomy, University of Chicago

Claudio Rubiliani, Docteur d’Etat. Honorary MCF Biologie des Organismes. Univ. Aix-Marseille (France)Visiting Professor Duke

Bjørn Ove Sætre, Developmental biology University of Bergen, Norway retired teacher

Lisa Sanders, Ph.D., Genetics, North Carolina State University

David Scadden, Professor, Stem Cell and Regenerative Biology and of Medicine, Harvard University

Julia Schaletzky, Professor of Molecular Therapeutics (Adj.), Dept. of Molecular and Cell Biology, University of California, Berkeley

Brandon Schmit, Wildlife Disease Biologist, USDA

Corrie Schoeman, Associate Professor, School of Life Sciences, University of KwaZulu Natal

Garvin Schulz, Dr., Department of Sociobiology/Anthropology, University of Göttingen

Elizabeth Sherman, Professor of Biology, Emerita, Bennington College

David Smith, Emeritus, Department of Biology, Williams College

Flavio S.J, de Souza, Group leader in Developmental Biology, IFIBYNE-CONICET, University of Buenos Aires, Argentina

Robert Paul Spence, Biotechnology company Chief Scientist

Steve Stewart-Williams, Professor of Psychology, University of Nottingham Malaysia

Malcolm Storey, PhD, naturalist retired

Mark Sturtevant, Associate Professor of Practice, Biological Sciences, Oakland University

John P. Sullivan, SSB member, PhD in Zoology, Duke University

Douglas Swartzendruber, Professor Emeritus, Biology, University of Colorado

Costas A. Thanos, Prof. Emer., Dept Biology, National and Kapodistrian University of Athens, Greece

Keith M. Vogelsang, Professor of Biology, Ivy Tech Community College

Schulte von Drach, Biologist (PhD). Journalist

Graham Wallis, Emeritus Professor, Population genetics and molecular evolution, University of Otago

Philip Ward, Professor Entomology, University of California Davis

Bob Warneke, Jr., BA (’73) and MS (’76) – Biology; Trinity University

Randy Wayne, Associate professor of plant biology, Cornell University

Marcelo Weksler, Professor, Museu Nacional, Universidade Federal do Rio de Janeiro, Brazil

Landon Whitby, Chemical Biologist, PhD, The Scripps Research Institute

Mike Zenanko, Director Emeritus, Jacksonville State University

Because it’s Sunday, we get another dollop of photos from John Avise, who continues his series on North American butterflies. John’s captions and IDs are indented, and you can enlarge the photos by clicking on them.

Butterflies in North America, Part 12 

This week continues my 18-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.

Mourning Cloak (Nymphalis antiopa), topwing:

Mourning Cloak, underwing:

Mourning Cloak, larvae on a host plant Arroyo Willow (Salix lasiolepis):

Mylitta Crescent (Phyciodes mylitta):

Northern Crescent (Phyciodes cocyta), topwing:

Northern Crescent, underwing:

Northern Pearly-eye (Lethe anthedon), underwing:

Northern White Skipper (Heliopetes ericetorum), topwing:

Northern White Skipper, underwing:

Ocola Skipper (Panoquina ocola) underwing:

Orange Sulphur (Colias eurytheme) underwing:

Orange-barred Sulphur (Phoebis philea), underwing:

On December 27th, 2024, the Chilean station of the Asteroid Terrestrial-impact Last Alert System (ATLAS) detected 2024 YR4. This Near-Earth Asteroid (NEA) belongs to the Apollo group, which orbits the Sun with a period of approximately four years. For most of its orbit, 2024 YR4 orbits far from Earth, but sometimes, it crosses Earth’s orbit. The asteroid was spotted shortly after it made a close approach to Earth on Christmas Day 2024 and is now moving away. Additional observations determined it had a 1% probability of hitting Earth when it makes its next close pass in December 2032.

This led the International Asteroid Warning Network (IAWN) – overseen by the United Nations Office for Outer Space Affairs (UNOOSA) – to issue the first-ever official impact risk notification for 2024 YR4. The possibility of an impact also prompted several major telescopes to gather additional data on the asteroid. This included the Subaru Telescope at the Mauna Kea Observatory in Hawaii, which captured images of the asteroid on February 20th, 2025. Thanks to the updated positional data from these observations, astronomers have refined the asteroid’s orbit and determined that it will not hit Earth.

This is not the first time the odds of the asteroid hitting Earth have been reevaluated. Throughout February, refined measurements of the asteroid altered the estimated likelihood multiple times, first to 2.3% and then to 3.1%, before dropping significantly to 0.28%. Thanks to the observations of the Subaru Telescope, which were conducted at the request of the JAXA Planetary Defense Team and in response to the IAWN’s call for improved orbital tracking, the chance of impact has been downgraded to 0.004%.

Monte Carlo modeling of 2024 YR4’s swath of possible locations as of February 23rd, 2025 – 0.004% probability of impact. Credit: iawn.net

The updated estimate was calculated by NASA’s Center for NEO Studies (CNEOS), the ESA’s Near-Earth Objects Coordination Centre (NEOCC), and the NEO Dynamic Site (NEODyS). The Subaru observations were conducted using the telescope’s Hyper Suprime-Cam (HSC), a wide-field prime-focus camera that captured images of 2024 YR4 as it grew dimmer. The observations have since been forwarded to the Minor Planet Center (MPC) of the International Astronomical Union (IAU). Dr. Tsuyoshi Terai of the National Astronomical Observatory of Japan (NAOJ), who led the observations, explained:

“Although 2024 YR4 appeared relatively bright at the time of its discovery, it has been steadily fading as it moves away from the Earth. By late February, observations would have been extremely challenging without a large telescope. This mission was successfully accomplished thanks to the Subaru Telescope’s powerful light-gathering capability and HSC’s high imaging performance.”

Based on these latest observations, the IAWN reports that 2020 YR4 will “pass at a distance beyond the geosynchronous satellites and possibly beyond the Moon.” They also indicate that there is no significant potential that the asteroid will impact Earth in the next century. The IAWN also states that it will continue to track 2024 YR4 through early April. At this point, it will be too faint to image and won’t be observable from Earth again until 2028.

Further Reading: NAOJ

The post Good News! The Subaru Telescope Confirms that Asteroid 2024 YR4 Will Not Hit Earth. appeared first on Universe Today.

There are several well-documented health risks that come from spending extended periods in microgravity, including muscle atrophy, bone density loss, and changes to organ function and health. In addition, astronauts have reported symptoms of immune dysfunction, including skin rashes and other inflammatory conditions. According to a new study, these issues could be due to the extremely sterile environment inside spacecraft and the International Space Station (ISS). Their results suggest that more microbes could help improve human health in space.

by Greg Mayer

As someone interested in history, I am both interested and wary when analogies are drawn among different periods and events in history, especially applying the past to the present day. And, as another prelude, I should note that I have said here before at WEIT that Bret Stephens is wrong about most things. But when he’s right, he’s right, and he’s right about yesterday’s cringe-inducing display of depravity by the erstwhile leaders of the free world, the President and Vice President of the United States. [JAC: You can find Stephens’s piece archived here.] I found Stephens’ historical analogy to the pre-Pearl Harbor meeting between Franklin D. Roosevelt and Winston Churchill, which led to the Atlantic Charter, whose principles include that there should be “no aggrandizement, territorial or other” and that “sovereign rights and self-government [shall be] restored to those who have been forcibly deprived of them”, very clarifying. Money quote:

If Roosevelt had told Churchill to sue for peace on any terms with Adolf Hitler and to fork over Britain’s coal reserves to the United States in exchange for no American security guarantees, it might have approximated what Trump did to Zelensky.

Interview with Adam Russell; News Items: Congestion Pricing, AI Therapists, Redefining Dyslexia, Small Modular Reactors for Cargo Ships; Who's That Noisy; Science or Fiction

Novel technology intends to redefine the virtual reality experience by expanding to incorporate a new sensory connection: taste.

Physicists provide a viable and testable explanation for how UHECRs are created.

In the race to meet the growing global demand for lithium -- a critical component in batteries for electric vehicles -- a team of researchers has developed a breakthrough lithium extraction method that could reshape the industry. In their study, the researchers demonstrated near-perfect lithium selectivity by repurposing solid-state electrolytes (SSEs) as membrane materials for aqueous lithium extraction. While originally designed for the rapid conduction of lithium ions in solid-state batteries -- where there are no other ions or liquid solvents -- the highly ordered and confined structure of SSEs was found to enable unprecedented separation of both ions and water in aqueous mixtures.

On December 3rd, 2018, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) successfully rendezvoused with the Near-Earth Asteroid (NEA) 101955 Bennu. Over the next two years, the mission collected rock and regolith samples from the asteroid’s surface. By September 24th, 2023, the mission’s sample return capsule (SRC) entered Earth’s atmosphere and was collected by NASA scientists. Analysis of these samples is already providing insight into what conditions were like during the early Solar System.

According to a recent study, the known trajectory and timing of the SRC’s return provided a rare opportunity to record geophysical signals produced by the capsule using a new method. Because it was traveling at hypersonic speeds as it flew through the atmosphere, the SRC’s return produced a sonic boom that impacted the ground. Using distributed acoustic sensing (DAS) interrogators and surface-draped fiber-optic cables, the team carried out the first reported recording of an SRC reentry with distributed fiber-optic sensing technology.

The team was led by Dr. Carly M. Donahue and consisted of her colleagues from the Earth and Environmental Sciences Division at the Los Alamos National Laboratory (LANL), as well as the Department of Geosciences at Colorado State University and fiber optic-based distributed sensor developer Silixa LLC. The paper that details their findings, “Detection of a Space Capsule Entering Earth’s Atmosphere with Distributed Acoustic Sensing (DAS),” recently appeared in the journal Seismological Research Letters.

The sample return capsule from the OSIRIS-REx mission is seen shortly after touching down in the Utah desert on September 24th, 2023. Credit: NASA/Keegan Barber

Since the end of the Apollo Era, scientists have studied sample return capsules re-entering Earth’s atmosphere. These studies have helped scientists develop safe and effective methods for sample-return missions and provided insight into the atmospheric entry of meteoroids and asteroids. Until now, these studies employed infrasound and seismic sensors to record the resulting geophysical signals. However, Dr. Donahue and her team saw an opportunity since the trajectory and timing of the OSIRIS-REx mission’s SRC were known in advance.

As Dr. Donahue told Universe Today via email, the reentry was a chance for them to test DAS systems with fiber optic cables to record the geophysical effects produced by the sonic boom. “DAS systems interrogating an optical fiber are still relatively rare,” she said. “Knowing ahead of time the precise trajectory gave us the scarce opportunity to situate multiple DAS interrogators near the point of highest heating and capture the sonic boom as it impacted the ground.”

The team rapidly deployed two DAS interrogators and more than 12 km (7.45 mi) of surface-draped fiber-optic cables. Their network included six collocated seismometer-infrasound sensor pairs, all spread across two sites near the town of Eureka in the Nevada Desert. As Dr. Donahue described:

“Once the team got the hang of rolling out the 4 spools of optical fiber that each weighed over 100 kgs, installing and retrieving the fiber took less time than setting up the six co-located seismic and infrasound stations. Approximately 5 km of the optical fiber was located at the local Eureka airport, along with many other teams deploying sensors such as infrasound, seismic, and GPS.  The other 7 km of fiber was located along a remote dirt road in Newark Valley.”

With the help of this network, the team obtained a stunning profile of the sonic boom as it struck the ground. The DAS interrogators recorded an impulsive arrival with an extended coda that had similar features to those recorded by the seismometers and infrasound sensors. Whereas traditional sensors only measure sonic booms at one point, Dr. Donahue said that her team’s data revealed how the boom’s wavefront transformed as it impacted the irregular terrain of the Nevada landscape.

In addition to being the first time these methods were used to record an SRC reentry, the results of this test could have significant implications when it comes to predicting potential meteor and asteroid strikes. Said Dr. Donahue:

“By having an extremely dense array of sensors, DAS has the possibility of better characterizing the trajectory and size of a meteor. The topology (e.g., hills) of the ground is known to have an influence on wavefront recorded at the surface of the earth. By having a dense line of sensors that span over the changes in the earth’s elevation, these effects could be better accounted for to produce a more accurate characterization of a meteor’s trajectory.”

Following the completion of its primary mission, the OSIRIS-REx, NASA prepped the spacecraft for the next phase of its mission. In 2029, the spacecraft – renamed the OSIRIS-APEX (Apophis Explorer) – will rendezvous with the Near-Earth Asteroid 99942 Apophis and collect another sample.

Further Reading: GeoScienceWorld

The post Detection of a Space Capsule Entering Earth’s Atmosphere with Distributed Acoustic Sensing (DAS) appeared first on Universe Today.

The Andromeda Galaxy, our nearest large neighbour, has 36 identified dwarf galaxies. The Hubble telescope took images of Andromeda and its dwarfs during more than 1,000 orbits, creating a precise 3D map. Astronomers used these observations to reconstruct the dwarf galaxies’ star formation histories.

The results show that their environment plays a critical role in their star formation and their quenching.

When galaxies are quenched, they no longer form stars. It happens because the supply of star-forming gas is diminished or somehow made unavailable. This typically happens because of black hole feedback or when a galaxy moves through a dense galaxy cluster, and its gas is stripped away.

However, the dwarf galaxies around Andromeda (M31) seem to follow an unusual pattern of star formation and quenching. New research shows that the rambunctious environment around M31 is responsible.

The research is “The Hubble Space Telescope Survey of M31 Satellite Galaxies. IV. Survey Overview and Lifetime Star Formation Histories,” published in The Astrophysical Journal. Alessandro Savino from the Department of Astronomy at UC Berkeley is the lead author.

Astronomers aren’t certain how many dwarf galaxies the Milky Way has, but it looks like Andromeda, with its dozens of dwarf galaxies, has had a more active history of mergers and absorptions. M 31 may have merged with another massive galaxy a few billion years ago, and its abundant dwarf galaxies could be from its eventful past and its sheer mass.

“Our knowledge of low-mass galaxy formation has long been anchored by Milky Way (MW) satellite galaxies,” the authors write. “It remains unclear if the insights learned from MW satellites, and their particular formation pathways, are applicable to other satellite systems and low-mass galaxies in general.”

“There’s always been concerns about whether what we are learning in the Milky Way applies more broadly to other galaxies.”

Daniel Weisz, UC Berkeley.

Studying dwarf galaxies is challenging. We’re inside the Milky Way, which makes observing its outskirts difficult. Dwarf galaxies are also dim, adding to their detection difficulty. Detecting them in distant galaxies is likewise difficult. Comparing the MW low-mass dwarf galaxies with those in other galaxies means contending with multiple layers of difficulty. Fortunately, the Andromeda galaxy is wide open to observations.

This large photomosaic of Andromeda is from the Hubble. It’s the largest one ever assembled from NASA/ESA Hubble Space Telescope observations. Click on the image to access the full-size version. Image Credit: NASA, ESA, B. Williams (University of Washington)

“From >1000 orbits of HST imaging, we present deep homogeneous resolved star colour-magnitude diagrams that reach the oldest main-sequence turnoff and uniformly measured star formation histories (SFHs) of 36 dwarf galaxies associated with the M31 halo,” the authors write. They did the same for 10 additional fields in M31, M33, and the Giant Stellar Stream. M33 is the Triangulum Galaxy, the third largest member of the Local Group after M31 and the Milky Way. M33 is also one of M31’s satellites. The Giant Stellar Stream is a long ribbon of stars that are the remnants of a galaxy absorbed by M31.

For context, this image shows some of the main features around Andromeda, including the Giant Stellar Stream, M32, and NGC 205, another of Andromeda’s dwarf galaxies. Image Credit: Ferguson et al. 2000

The observations reveal a tight correlation between a dwarf’s star formation history, its mass, and its proximity to M31.

“We see that the duration for which the satellites can continue forming new stars really depends on how massive they are and on how close they are to the Andromeda galaxy,” said lead author Savino in a press release. “It is a clear indication of how small-galaxy growth is disturbed by the influence of a massive galaxy like Andromeda.”

Astronomers are in a difficult spot when it comes to studying galaxies in detail. Our own Milky Way is the only galaxy that’s open to detailed investigation. The temptation is to draw parallels between our knowledge of the MW and other galaxies.

“There’s always a tendency to use what we understand in our own galaxy to extrapolate more generally to the other galaxies in the universe,” said principal investigator Daniel Weisz of the University of California at Berkeley. “There’s always been concerns about whether what we are learning in the Milky Way applies more broadly to other galaxies. Or is there more diversity among external galaxies? Do they have similar properties? Our work has shown that low-mass galaxies in other ecosystems have followed different evolutionary paths than what we know from the Milky Way satellite galaxies.”

These detailed, 1,000-orbit observations of Andromeda are helping change this. They reveal a more chaotic environment than in the Milky Way.

“Everything scattered in the Andromeda system is very asymmetric and perturbed. It does appear that something significant happened not too long ago,” said Weisz.

One of the research’s surprising findings is that about half of M31’s dwarf galaxies lie along the same plane, called the Great Plane of Andromeda, and are moving in the same direction. “That’s weird. It was actually a total surprise to find the satellites in that configuration, and we still don’t fully understand why they appear that way,” said Weisz.

The galaxies along this plane don’t appear to be any different from those on the plane. “There is no difference between the median SFH (star formation history) of galaxies on and off the great plane of Andromeda satellites,” the authors write.

The researchers used colour-magnitude diagrams (CMDs), an important tool in astronomy, to learn more about the star formation history in Andromeda’s dwarf galaxies. CMDs plot a star’s magnitude, or brightness, with its colour. From these plots, astronomers can learn about the age of a stellar population and when star formation was quenched.

The CMDs showed that star formation in dwarf galaxies lasts much longer than expected. It started early and continued, albeit more slowly, by drawing from a reservoir of gas. These results are in sharp disagreement with simulations like TNG 50.

“Star formation really continued to much later times, which is not at all what you would expect for these dwarf galaxies,” said Savino. “This doesn’t appear in computer simulations. No one knows what to make of that so far.”

This figure from the team’s research shows the star formation history (SFH) in Andromeda’s halo, the Giant Stellar Stream, and M33. The red region represents the Epoch of Reionization, the black line shows the best-fit SFH and the grey shows systematic uncertainties. It shows that star formation started early and continued for a long time, albeit at a much slower rate. Image Credit: Savino et al. 2025.

The research also shows that the SFH is no different between dwarf galaxies on the Great Plane of Andromeda and those off of it.

This figure from the study shows the median SFH for the GPoA candidate members (blue line, left panel) and out-of-plane candidates (orange line, middle panel). The gray lines show the SFH of individual galaxies. The right panel shows a direct comparison between the median SFH of the two samples. Image Credit: Savino et al. 2025.

The SFH results in Andromeda are not what we see in the MW. This suggests that the environmental histories, tidal forces, and gas stripping experienced by M31 satellites are different than those around the Milky Way, leading to different star formation patterns over cosmic time. This could be the most significant finding and further exemplifies the risk of extrapolating our knowledge of the Milky Way to other galaxies.

“The results of this study represent a significant step forward in our understanding of the M31 satellite system,” the authors write in their conclusion. They point out that the SFHs they’ve developed will only be more valuable when combined with large data sets acquired in the future. Data sets of the spectral abundance of stars and their proper motions in M31 are being acquired, and some already exist.

Maybe they’ll be able to explain Andromeda’s dwarf galaxies’ unusual properties.

“We do find that there is a lot of diversity that needs to be explained in the Andromeda satellite system,” added Weisz. “The way things come together matters a lot in understanding this galaxy’s history.”

• Press Release:

The post Andromeda’s Dwarf Galaxies Reveal Unique Star Formation Histories appeared first on Universe Today.

When the US Federal Emergency Management Agency removed a map of future climate hazards from its website, researchers built their own version

Rogue planetary-mass objects, also known as free-floating planets (FFPs) drift through space alone, unbound to any other objects. They’re loosely defined as bodies with masses between stars and planets. There could be billions, even trillions of them, in the Milky Way.

Their origins are unclear, but new research says they’re born in young star clusters.

Some free-floating planets (FFPs) form the same way stars form by collapsing inside a cloud. The International Astronomical Union calls them sub-brown dwarfs. But that can’t account for all FFPs, or isolated planetary-mass objects (iPMOs) as they’re sometimes called.

New research in Science Advances shows how FFPs form in young star clusters where circumstellar disks interact with one another.

“This discovery partly reshapes how we view cosmic diversity.”

Lucio Mayer, University of Zurich

The research is titled “Formation of free-floating planetary mass objects via circumstellar disk encounters.” Zhihau Fu from the Department of Physics at the University of Hong Kong and the Shanghai Astronomical Observatory is the lead author, and Lucio Mayer from the University of Zurich is the corresponding author.

“PMOs don’t fit neatly into existing categories of stars or planets,” said corresponding author Meyer. “Our simulations show they are probably formed by a completely different process.”

Astronomers found some of the first evidence of PMOs in the Trapezium Cluster in the year 2,000. The Trapezium is a tight, open cluster of stars in Orion. It’s also relatively young, and half of its stars show dwindling circumstellar disks, a sign that planet formation is taking place. In the research published in 2,000, the authors wrote that “Approximately 13 planetary-mass objects are detected.”

This Hubble Space Telescope image shows the Orion Nebula with the three stars of Orion’s belt prominent. The Trapezium cluster is the bright clump of stars above and to the right of the belt. Most of Trapezium’s stars are obscured by dust. In 2,000, astronomers first found evidence of rogue planets in the Trapezium Cluster. Image Credit: By NASA, ESA, M. Robberto (Space Telescope Science Institute/ESA) and the Hubble Space Telescope Orion Treasury Project Team – http://hubblesite.org/newscenter/newsdesk/archive/releases/2006/01/https://www.spacetelescope.org/news/heic0601/, Public Domain, https://commons.wikimedia.org/w/index.php?curid=1164360

Since then, astronomers have found many more PMOs and hundreds more candidates. Scientists have wondered about their origins, but so far, there are no widely accepted explanations.

“The origin of planetary mass objects (PMOs) wandering in young star clusters remains enigmatic, especially when they come in pairs,” the authors write in their new research. “They could represent the lowest-mass object formed via molecular cloud collapse or high-mass planets ejected from their host stars. However, neither theory fully accounts for their abundance and multiplicity.”

The researchers used hydrodynamic simulations to test another origin for PMOs and found that they have a unique origin story. Instead of forming in a collapsing cloud like stars or in a protoplanetary disk around a young star, they form in the dense environments in young star clusters. The densely packed environments provide another pathway for PMO formation.

In their simulations, the researchers recreated some of the conditions inside young star clusters where stars readily interact with one another. During close encounters between two stars, their circumstellar disks interact. They get stretched into a tidal bridge between the pair of stars, and the gas in the bridge is also compressed into a greater density.

In the simulations, these bridges collapse into filaments, and those filaments collapse even further into dense cores. Eventually, these cores form PMOs of about 10 Jupiter masses. This fruitful process produces many pairs and triplets of PMOs. Astronomers observe a high number of PMO binaries in some clusters, so these simulations appear to match observations.

“Many young circumstellar disks are prone to instabilities due to the self-gravity of disk gas, potentially leading to disk fragmentation and the formation of gaseous planets,” the authors explain in their paper. “Circumstellar disks appear even more unstable when perturbed by a stellar or circumstellar disk flyby.”

This figure from the research shows some of the simulation results. The top panel shows a pair of young stars with interacting circumstellar disks. Two dense cores are forming in the interaction. The bottom panel shows four snapshots from the simulation at different elapsed times. The binary PMOs form in the dense filaments generated in the stellar encounter. Image Credit: Fu et al. 2025.

Even stable and isolated disks can form PMOs during flybys. However, the formation of PMOs is dependent on the combined velocity of the interactions. “For high- and low-velocity encounters, the tidal bridge is either stretched too thin or torn apart by the stars, and thus, forming isolated cores becomes impossible,” the authors explain. The interaction velocity has to be in the middle range.

Some of their simulations also showed up to four PMO cores forming in the filaments. “The middle part of the tidal bridge contracts into thin filaments with line mass over the critical value for stability, forming up to four cores in one encounter,” the researchers write. They explain that the exact number of cores is determined by the length of the filaments and is “sensitive to random density fluctuations.” These fluctuations are very difficult to predict from the encounter parameters.

The PMOs display some particular characteristics. They’re likely to have their own disks, and they’re likely to be metal-poor because of where they get their dust from. “In addition, PMOs and their hosts are expected to be metal-poor since they inherit materials in the parent disks’ outskirts that are susceptible to dust drift and, thus, are metal-depleted,” the authors explain.

The authors calculate that in just one million years, which is the approximate age of the Trapezium Cluster, each star will experience 3.6 encounters with other stars. “The highly efficient PMO production channel via encounters can, therefore, explain the hundreds of PMO candidates (540 over 3500 stars) observed in the Trapezium cluster,” the authors write.

It’s important to note that the results only apply to dense clusters that force interactions between circumstellar disks. “This process can be highly productive in dense clusters like Trapezium forming metal-poor PMOs with disks. Free-floating multiple PMOs also naturally emerge when neighbouring PMOs are caught by their mutual gravity,” the authors write.

“This discovery partly reshapes how we view cosmic diversity,” said co-author Lucio Mayer. “PMOs may represent a third class of objects, born not from the raw material of star forming clouds or via planet-building processes, but rather from the gravitational chaos of disk collisions.”

PMOs can be difficult to spot, so their population is based on preliminary estimates and understandings. But they’re out there, and we’ll only get better at identifying them.

This artist’s impression shows an example of a rogue planet with the Rho Ophiuchi cloud complex visible in the background. Rogue planets have masses comparable to those of the planets in our Solar System but do not orbit a star, instead roaming freely on their own. Image Credit: ESO/M. Kornmesser/S. Guisard

The Upper Scorpius Association contains the next highest-known population of PMOs. A 2021 study identified between 70 and 170 candidate PMOs in the region.

The soon-to-see-first-light Vera Rubin Observator (VRO) will significantly grow the number of known PMOs. More data is better data, and the VRO’s observations will lead to a better understanding of how they form.

“Future studies of various young clusters can further constrain the population of PMOs,” the authors conclude.

• Press Release: Young Star Clusters Give Birth to Rogue Planetary-Mass Objects
• New Research: Formation of free-floating planetary mass objects via circumstellar disk encounters

The post Rogue Planets are Born in Young Star Clusters appeared first on Universe Today.

I got no news today, so I’ll put up some music. This happens one of my favorite jazz solos, and I don’t think I’ve posted it before but came across it on YouTube. It’s a smoking trumpet piece played by Roy Eldridge (1911-1989), nicknamed “Little Jazz” because of his stature. Here he plays with the Gene Krupa Orchestra, and later he played with Artie Shaw’s band.  Unable to form his own big band, Eldredge later confined himself, like Charlie Parker, to small groups.

This rendition of “Rockin’ Chair” is smoking, one of the best trumpet pieces I know. Wikipedia singles it out:

One of Eldridge’s best known recorded solos is on a rendition of Hoagy Carmichael‘s tune, “Rockin’ Chair”, arranged by Benny Carter as something like a concerto for Eldridge. Jazz historian Gunther Schuller referred to Eldridge’s solo on “Rockin’ Chair” as “a strong and at times tremendously moving performance”, although he disapproved of the “opening and closing cadenzas, the latter unforgivably aping the corniest of operatic cadenza traditions.” Critic and author Dave Oliphant describes Eldridge’s unique tone on “Rockin’ Chair” as “a raspy, buzzy tone, which enormously heightens his playing’s intensity, emotionally and dynamically” and writes that it “was also meant to hurt a little, to be disturbing, to express unfathomable stress.”

If you want to hear a very different (but also good) rendition, go here to hear a duo with Louis Armstrong and trombonist Jack Teagarden. This one has vocals.

Virtual reality could get more realistic thanks to scientists inventing an artificial tongue that can taste flavours, such as sourness and umami