Palau Is An Oceania Outlier

This is a further refinement of an already pretty well worked out story of Oceanian origins. 

The ultimate source of Oceanian and Austronesian seafaring people was one of the indigenous tribes of what is now called Taiwan (we have identified which of them it was based upon linguistic evidence), via island Southeast Asia.  

Before expanding very far east, however, these Formosan origin Lapita people admixed with Papuan people (in an encounter that amounted to a hostile conquest).

This "graphical abstract" really sums up a new paper on the topic. 

Note that the dates in this image are "before present", i.e. before 1950 by archeological convention, and not BCE. The initial settlement of Palau was roughly contemporaneous with the Greek "dark ages" after Bronze Age collapse, for example, while the admixture of the people who settled Palau was contemporaneous with the Late Bronze Age in Europe.

An educated layman's explanation of the paper explains: 

About 3200 years ago, Southeast Asian seafarers known as the Lapita pushed east into the tropical islands of the Pacific Ocean, hitting nearly every habitable isle in that corner of the globe from New Guinea to Fiji and Tonga. As they did so, they left behind artifacts of their culture, including pottery stamped with distinctive geometric patterns.

But on Palau, there’s not a single shard of Lapita pottery—and the island’s inhabitants speak a language that’s distinct from the tongues spoken on other Pacific islands. So who were the first Palauans, and where did they come from?

A new study published last week in Cell suggests an answer. Genetic evidence confirms Palau’s first settlers descended from Southeast Asians who had intermingled with the Papuans, Indigenous peoples who settled the island of New Guinea some 50,000 years ago.

“It’s lovely to see a piece of Pacific history—which we’ve traditionally been at a bit of a loss to explain—finally start to come together into a more understandable story,” says Murray Cox, a computational biologist at Massey University of New Zealand who wasn’t involved in the new work.

The discovery builds on previous ancient DNA research into the origins of the Lapita themselves. That work, led by evolutionary biologist David Reich at Harvard University and his colleagues, showed that Lapita were essentially pure Southeast Asians of Taiwanese roots—but that modern populations on Pacific islands showed Papuan ancestry, too. The studies suggested this Papuan ancestry came in about 2500 years ago, as Papuans began to join the same canoe voyages that had earlier carried Lapita settlers into the region.

From Science.

The underlying paper in Cell is as follows:

Highlights

• Ancient DNA of 21 individuals from Palau spans around 2,400 years

• Papuan-East Asian admixture in Palauans predates initial settlement

• Over 2,900 years of genetic continuity in Palau

• Shared East Asian-Papuan admixture in Palau and eastern Indonesia 

Summary 

The first people reached Remote Oceania 3,000 years before present (BP), arriving roughly simultaneously in the southwest Pacific, the Marianas Archipelago, and Palau. However, no genome-wide ancient DNA data have been available from Palau, a gap we address by reporting 21 individuals from four archaeological sites dating between 2,900 and 500 BP. 

All had approximately 60% ancestry related to East Asians and 40% to Papuans, similar to present-day Palauans, the longest stretch of population continuity anywhere in Remote Oceania. The lengths of contiguous Papuan ancestry segments in the oldest individuals show that major admixture between Papuans and East Asians in the ancestors of all sampled Palauans began prior to first settlement. This differs from the pattern in the southwest Pacific, where sampled individuals of the Lapita archaeological culture from three different islands had almost entirely East Asian ancestry, with large amounts of Papuan admixture observed only hundreds of years later. 

Yue-Chen Liu, et al., "Papuan admixture predated the settlement of Palau" (March 10, 2026).

A System With Three Galaxies Showing No Dark Matter-Like Phenomena

This is also consistent with the MONDian External Field Effect explanation.

While most dwarf galaxies are strongly dark matter dominated, two remarkable objects in the NGC 1052 field, DF2 and DF4, appear to lack dark matter. DF2 and DF4 were recently found to be part of a trail of low luminosity galaxies that follow a linear relation between their position on the trail and their radial velocity. If the other galaxies on this trail formed together with DF2 and DF4, e.g., from gas that was separated from dark matter through a 'bullet dwarf' collision, they may lack dark matter as well. 

Here we constrain the dark matter content of DF9, the galaxy on the trail that most closely resembles DF2 and DF4. Using Keck/KCWI absorption line spectroscopy we find that DF9's stellar velocity dispersion is 6.4 + 4.0 − 4.3 km/s. This is consistent with the 8.3 + 0.9 − 1.4 km/s dispersion that is expected from DF9's 1.4 × 10^8 M⊙ stellar mass alone, and we conclude that -- like DF2 and DF4 -- dark matter is not required to explain the kinematics of DF9. The dispersion is far below the 27 ± 3 km/s expected if DF9 fell on the stellar mass--halo mass relation. Our results are further evidence that the trail of low mass galaxies in the NGC 1052 field formed together in a unique galaxy formation channel, and are consistent with the prediction of the bullet dwarf scenario that other trail galaxies should show the same lack of dark matter as DF2 and DF4.

Michael A. Keim, Pieter van Dokkum, Zili Shen, Shany Danieli, Imad Pasha, "A Third Galaxy Missing Dark Matter along a Trail of Galaxies in the NGC 1052 Field" arXiv:2603.15860 (March 16, 2026) (Submitted to ApJL).

Yet Another Observational Problem With The ΛCDM Model

The ΛCDM model is contradicted by a host of independent observational tests (dozens of them). 

The luminosity-temperature relation for galaxy clusters is independent of any of these previous tests and doesn't share significant sources of systemic error with it. And, the ΛCDM, again, is not a good fit to this data, while one of the more well-studied modified gravity theories, f(R) gravity, does significantly better.

We investigate the luminosity-temperature (L-T) relation of galaxy clusters as a probe for testing modified gravity (MG) theories, focusing on f(R) gravity and symmetron models. Using an improved semi-analytic framework that incorporates angular momentum acquisition, dynamical friction, and shock heating within the modified punctuated equilibrium model, we compare predictions against hydrodynamical simulations and observational data. 

While massive clusters remain largely screened and follow standard ΛCDM predictions, low-mass systems (kT ≲ 1−2 keV) exhibit systematic deviations characterized by steeper L-T slopes in MG scenarios. 

Crucially, we demonstrate that these signatures cannot be mimicked by conventional astrophysical processes such as feedback or angular momentum effects, which primarily affect normalization rather than curvature. Our results establish the L-T relation as a robust diagnostic tool for distinguishing general relativity from screened MG theories, with the strongest discriminatory power emerging at group scales accessible to current and future X-ray surveys. Moreover, a normalized reduced χ2 analysis of the L-T relation shows that MG models provide significantly better agreement with observational data than ΛCDM, with several realizations achieving excellent fits while the ΛCDM model consistently performs worst.

Antonino Del Popolo, Saeed Fakhry, David F. Mota, "Luminosity-Temperature Relation as a Probe for Modified Gravity" arXiv:2603.15077 (March 16, 2026).

See also this paper, which finds fault with the NFW halo distribution which is mathematically implied in any collisionless dark matter particle model, yet clearly time and again, does not reflect real world observations.

We investigate how reliably the global properties of Milky Way-mass dark matter haloes can be recovered from dynamical data over a limited radial range, particularly ≲30 kpc where observations are most sensitive but baryonic processes modify the halo structure. 

Using the ARTEMIS simulations, which produce varying degrees of baryon-induced contraction, we fit dark matter profiles over restricted radial ranges using commonly adopted parametric models. Assuming negligible observational uncertainties allows the systematic errors from these choices to be isolated. 

When fits are confined to inner radii, an NFW profile underestimates the virial mass by a factor of ≈2 on average (≈4 for some systems), and the concentration by a factor of ≈2. Einasto and generalised-NFW models provide excellent local fits but retain similar global biases. 

In contrast, the contracted halo prescription from Cautun et al. (2020) yields stable extrapolations and recovers unbiased halo mass estimates over all radii. 

The inferred mass improves systematically with increasing radial coverage, and tracers beyond ≳50 kpc largely eliminate the mean bias for all models. The local dark matter density at the Solar radius is recovered to within ≲5% for all profiles other than NFW. These biases are sufficient to reconcile recent low Milky Way mass estimates derived from inner rotation-curve analyses with the canonical ≈ 10^12 M⊙. 

We additionally find a halo-to-halo scatter of ≳0.1 dex (≈25%) persists even under idealised conditions, setting a likely lower limit for the precision of halo mass estimates.

Diego Dado, Shaun T. Brown, Azadeh Fattahi, Andreea S. Font, Ian G. McCarthy, "Implications of a contracted dark matter halo for the Milky Way's inferred virial mass" arXiv:2603.13516 (March 13, 2026) (submitted to MNRAS).

Some analysis of the measurement issues for galactic rotation curve of the Milky Way are discussed here.

Predicting Heavy Hadron Masses

This paper makes mass predictions for a huge number of three and five valence quark hadrons (in both ground states and excited states) made by both traditional methods from the literature and AI models, producing multiple estimates by different methods for each hadron considered. It is mostly a pattern recognition exercise, rather than a set of calculations from QCD first principles. It predicts several hundred composite particle masses.

This is easier for baryons (i.e. half-integer spin fermions) than for mesons (i.e. integer spin bosons) because baryons have far fewer quirky exceptions to general rules that flow, in part, from different mesons blending into each other, which is something that baryons don't do.

One observation is that these several hundred heavy baryons (in the broad sense of half integer spin hadrons, rather than the narrow sense of three valence quark hadrons) fill a pretty narrow range of masses, with the lightest having a mass of about 1.5 GeV, the heaviest having a mass of 11.4 GeV, and most of the predicted masses bunching up in the middle, with more than 4 GeV and less than 10 GeV. The lightest pentaquarks are a bit over 4 GeV.

Given that there are only a handful of possible quantum numbers for each hadron, the experimental task of distinguishing one heavy baryon from another would be challenging, with many possibilities near any given mass. 

While experimental mass measurement of heavy baryons typically have uncertainties of a few MeV, the uncertainties in the theoretical mass predictions are much greater. The theoretical uncertainties of the predictions range from about 100 to 2000 MeV, with most in the range of about 450 to 1200 MeV. The differences between theoretical mass predictions methods for the same hadron also frequently exceed the combined claimed uncertainties in the predictions, however, so the uncertainties are probably underestimated.

Since it is easy to make predictions if they are vague enough, which makes it easy for the predictions to be consistent with the experimentally observed values, the significance of these models shouldn't be exaggerated. They are making very ballpark estimates based upon very general considerations. 

But because it is so comprehensive, this is still somewhat useful in winnowing down candidates for a particular observed resonance with a particular observed mass from several hundred possibilities to perhaps a few dozen likely candidates of similar mass, which can be narrowed down further with measurements of the resonances spin, charge, and other quantum numbers to perhaps a dozen or fewer candidates.

In this article, we use two different methods for studying the mass spectra of fully-heavy baryons and pentaquarks. 

In the first section, we use state-of-the-art machine learning methods, such as deep neural networks and the Particle Transformer model architecture, to predict baryon masses directly from their quantum numbers, based on experimental information on hadrons from the Particle Data Group (PDG). We use this data-driven approach for the case of fully heavy baryons, and a large number of exotic pentaquark states, going much beyond the well-known P+c(4380) and $ P_c^+(4457) candidates. Subsequently, we extend the Gürsey-Radicati mass formula to incorporate the contributions of charm and bottom quarks, enabling analytical calculations for both ground and radially excited states of baryons and pentaquarks. 

The results obtained from both approaches demonstrate strong agreement with experimental data where available and make predictions for a number of unobserved states, including higher radial excitations. By addressing the question through both data-driven prediction and analytical modeling in different frameworks, this study offers complementary insights into the mass spectrum of conventional and exotic hadrons, guiding future experimental searches.

S. Rostami, A. R. Olamaei, M. Malekhosseini, K. Azizi, "Comprehensive Mass Predictions: From Triply Heavy Baryons to Pentaquarks" arXiv:2603.11259 (March 11, 2026).

An Unreview

What makes this paper especially notable is not its content per se but the concept of an "unreview", which potentially has broad interdisciplinary applications.

Accreting white dwarfs (AWDs) are among the best natural laboratories for understanding disk accretion. Their proximity, brightness, and purely classical nature make them ideal systems in which to probe the fundamental physics that governs the transport of angular momentum, the generation of outflows, and the coupling between disks, magnetospheres, and accretors. Yet despite decades of study, many critical questions remain unresolved. 

In this ``unreview'', we therefore focus not on what is known, but on what is unknown. 

What drives viscosity and sustains accretion in largely neutral disks? How are powerful winds launched, and how do they feed back on the disk and binary evolution? Why do so many systems show persistent retrograde precession, and what drives bursts in magnetic AWDs? 

By identifying these open problems -- and suggesting ways to resolve them -- we aim to motivate new observational, numerical, and theoretical efforts that will advance our understanding of accretion physics across all mass scales, from white dwarfs to black holes.

Simone Scaringi, Christian Knigge, Domitilla de Martino, "Accreting White Dwarfs: An Unreview" arXiv:2603.10150 (March 10, 2026) (Accepted in Space Science Reviews).

Also notable is a paper demonstrating that a twenty times faster method of computing big data in cosmology is indistinguishable in its results from a more conventional method of doing so, despite the fact that the faster method isn't obviously theoretically rigorous and sound (because it uses linear rather than non-linear mathematical methods).

There is also a new paper replicating a result of a 2026 paper finding MOND-like effects in wide binaries using a modestly different analysis method.

Variations On Tully-Fischer

The Baryonic Tully-Fischer relation (a tight correlation between ordinary matter and inferred total mass) holds much more tightly than a parallel correlation considering only ordinary matter in stars.

We combine data for extragalactic systems to quantify a relation between the observed baryonic mass Mb and the enclosed dynamical mass M200 inferred from kinematics or gravitational lensing. Our sample covers nine orders of magnitude in baryonic mass, including galaxies with kinematic or weak gravitational lensing data and groups and clusters of galaxies with new gravitational lensing data. 

For rich clusters with M(b)>10^14M⊙, the observed baryon fraction is consistent with the cosmic value, f(b)=0.157. 

For lower masses, the baryon fraction decreases systematically with mass. The variation is well described by M(b)/M(200)=f(b) tanh(M(b)/M(0))^1/4 with M(0) ≈ 5 × 10^13 M⊙. 

This relation is qualitatively similar to stellar mass-halo mass relations derived from abundance matching, but exhibits less scatter.

Stacy McGaugh, Tobias Mistele, Francis Duey, Konstantin Haubner, Federico Lelli, Jim Schombert, Pengfei Li, "The Baryonic Mass-Halo Mass Relation of Extragalactic Systems" arXiv:2603.06479 (March 6, 2026) (Accepted for publication in the Astrophysical Journal).

A Muon g-2 Recap

Ref. [8] is R. Aliberti et al., The anomalous magnetic moment of the muon in the Standard Model: an update, Phys. Rept. 1143 (2025) 1 [arXiv:2505.21476].

A paper on the latest developments of calculating muon g-2 (the anomalous magnetic moment of the muon which can be calculated in the Standard Model from first principles) in the latest BMW group calculation not only updates their calculation to be more precise (and consistent with the high precision experimental results), but also provide excellent background for the entire enterprise of calculating muon g-2 and comparing it to the experimental results.

The overview of the paper is as follows:

Almost twenty years ago, physicists at Brookhaven National Laboratory measured the magnetic moment of the muon with a remarkable precision of 0.54 parts per million (ppm) [20]. Since that time, the reference Standard Model prediction forth is quantity has exhibited a persistent discrepancy with experiment of more than three sigma [9]. This raises the tantalising possibility of undiscovered forces or elementary particles. The attention of the world was drawn to this discrepancy when Fermilab presented a brilliant confirmation of Brookhaven’s measurement, which brought the discrepancy to 4.2 sigma [21]. In the meantime a very large-scale lattice QCD calculation of a key theoretical contribution was performed by the Budapest-Marseille-Wuppertal (BMW) collaboration [3], as seen in Fig. 1. This result significantly reduces the difference between theory and experiment, suggesting that new physics may not be needed to explain the experimental results. However, it simultaneously introduces a new discrepancy with the existing data-driven determination of this contribution. 

Since then, the experimental [2] results have been updated with significantly improved precision, and the lattice result has been independently confirmed by other lattice collaborations. At the same time, new developments in the data-driven inputs that the lattice calculations replace [17–19] lead to a significant spread in the results depending on what inputs are taken. This has culminated in an updated theory prediction based on the lattice results instead of the data-driven determinations, as seen in Fig. 1. 

In these proceedings, I present a new hybrid calculation that combines an update to the most precise lattice results with data-driven inputs in a low-energy region where the observed discrepancies are not present. This new result leads to aprediction that differs from the experimental measurement by only 0.5𝜎, providing a remarkable validation of the Standard Model to 0.31 ppm.

As Table 1 shows, the main problem is how to more precisely measure the Hadronic Vacuum Polarization (HVP) component more precisely.

According to the abstract: 

The latest results from the Budapest-Marseille-Wuppertal (BMW) and DMZ collaborations, . . . [make] a determination of the hadronic vacuum polarisation contribution to a precision of 0.45%. [i.e. from ± 6.1 to ± 3.2.]

This new calculation is about twice as precise as the previous HVP calculation. 

The conclusion of the paper states that:

Recent lattice QCD results have surpassed the precision of all other theoretical predictions of the hadronic vacuum polarisation contribution to the muon magnetic moment. When taken together with the latest theory consensus for the other contributions [8], these results show excellent agreement with the latest experimental measurements [2]. This a remarkable success for quantum field theory, bringing together diverse computational tools to include all aspects of the Standard Model in a single calculation that validates the Standard Model to 0.31 ppm.

As a practical matter, this further tightens global constrains on low to medium energy deviations from the Standard Model. 

Mirror Universes And Dark Energy?

An interesting idea, coupled to one of the most plausible explanations for baryon asymmetry and what came before the Big Bang, even if it may not actually be provable.

We investigate a possible resolution of the dark energy problem within a pair-universe framework, in which the Universe emerges as an entangled pair of time-reversed sectors. 

In this setting, a global zero-energy condition allows vacuum energy contributions from the two sectors to cancel, alleviating the need for extreme fine-tuning. We propose that the observed dark energy does not originate from vacuum fluctuations but instead arises as an effective entanglement energy between the visible universe and its mirror counterpart. 

Treating the cosmological constant as an integration constant fixed by boundary conditions rather than a fundamental parameter, we show that the cosmological equations can be formulated without explicitly introducing vacuum energy. By imposing physically motivated boundary conditions at the cosmological event horizon, we obtain an integration constant consistent with the observed dark energy density. The parallel mirror world scenario thus provides a unified framework that may simultaneously explain the origins of dark energy and dark matter.

Merab Gogberashvili, Tinatin Tsiskaridze, "Dark Energy from Entanglements with Mirror Universe" arXiv:2603.03385 (March 3, 2026) (published at 8 Physics 29 (2026)).

MOND-like Behavior Within The Milky Way In Milky Way Subsystems

The radial acceleration relation and baryonic Tully-Fischer relation, while not perfect, work far too well to be consistent with almost any dark matter particle theories (ultra-light bosonic dark matter still might be possible to make work).

We test whether parsec-scale stellar systems in the Milky Way follow the galactic radial acceleration relation (RAR) or the baryonic TullyFisher relation (BTFR). 

We analyse 5646 Gaia DR3 open clusters from the Hunt & Reffert catalogue. Observed accelerations are derived from velocity dispersions and characteristic radii, and baryonic accelerations from stellar masses and characterisitc radii. The clusters are placed on the RAR and BTFR planes and compared with Newtonian and MOND expectations. Approximately 90 per cent of open clusters (those with N⋆≤250) lie close to the RAR, albeit with significant scatter. In a first-of-its-kind test, a smaller fiducial sample is consistent with a best-fitting acceleration scale g†≈1.2×10−10 ms−2±0.5 dex, compatible with canonical MOND values. 

More massive clusters approach the Newtonian virial expectation. No correlations are found between RAR residuals and galactocentric radii, distance to the Galactic disk midplane, age, or morphology. Tidal effects and unresolved binaries are insufficient to reproduce the observations without fine-tuning. 

Interpreted within a MOND framework, the alignment of most open clusters with the RAR and BTFR suggests that low-acceleration dynamics operate on parsec scales within the Milky Way. This implies that the Galactic gravitational field is not smooth on these scales and may include regions where the total gravitational acceleration falls below a0, partially mitigating the external field effect, thereby motivating higher-resolution modelling of the Galactic potential and informing other small-scale gravity tests within the Galaxy.

Mark D. Huisjes, X. Hernandez, "Most open clusters follow the radial acceleration relation (RAR) and the baryonic Tully-Fisher relation (BTFR)" arXiv:2603.03522 (March 3, 2026).

The Wide Binary Wars Continue

Neither the astrophysicists who say that there is evidence of MOND in wide binaries, nor those who say there is not, are relenting, and I currently rate the debate as inconclusive.

If this paper is right, it is bad for MOND, but good for Deur, who reproduces MOND behavior in galaxies by another formula and mechanism.

Wide binaries (WBs) offer a unique opportunity to test gravity in the low-acceleration regime, where modifications such as Milgromian dynamics (MOND) predict measurable deviations from Newtonian gravity. 

We construct a rigorous framework for conducting the wide binary test (WBT), emphasizing high quality sample selection, filtering of poor astrometric solutions, contamination mitigation, and uncertainty propagation. We show that undetected close binaries, chance alignments, and improper treatment of projection effects can mimic MOND-like signals. We introduce a checklist of best practices to identify and avoid these pitfalls. Applying this framework to Gaia DR3 data, we compile a high-purity sample of WBs within 130 pc with projected separations of 1 - 30 kAU, spanning the transition between the Newtonian and MOND regimes. 

We find that the scaled relative velocity distribution of wide binaries does not exhibit the 20% enhancement expected from MOND and is consistent with Newtonian gravity across all separations. A meta-analysis of previous WBTs shows that apparent MOND signals diminish as methodological rigour improves. We conclude that when stringent quality controls are applied, there is no observational evidence for MOND-induced velocity boosts in wide binaries. 

Our results place strong empirical constraints on modified gravity theories operating between a0/10 and 200 a0, where a0 is the MOND acceleration scale. Across this range of internal accelerations, Newtonian gravity is up to 1500x more likely than MOND for our cleanest sample.

Stephen A. Cookson, Indranil Banik, Kareem El-Badry, Will Sutherland, Zephyr Penoyre, Charalambos Pittordis, Cathie J. Clarke, "A Quality Framework for Testing Gravity with Wide Binaries: No Evidence for MOND" arXiv:2602.24035 (February 27, 2026) (published in MNRAS).

Gender And Neanderthal-Modern Human Interbreeding

The New York Times and other general audience media outlets are reporting on a new genetics study in the Journal Science, examining the gender dynamics of Neanderthal admixture. The editor's summary and abstract and citation are:

Editor’s summary

Although a low level of Neanderthal ancestry is present in most humans, these regions are not uniformly distributed. A handful of regions in the autosome are entirely devoid of such ancestry in essentially all living humans, and the X chromosome is strongly depleted across its sequence. Platt et al. modeled the possible demographic processes and selection that could have produced this pattern. They found that these patterns are most consistent with Neanderthal contributions to human populations being heavily male biased. The concurrent additional depletion in functional regions on the X chromosome suggests that the effects of this skew may have been strengthened by negative selection on Neanderthal variants. —Corinne Simonti

Abstract

Sex biases in admixture and other demographic processes are recurrent features throughout human evolution. For admixture between Neanderthals and anatomically modern humans (AMHs), sex bias has been proposed as an explanation for the relative lack of Neanderthal ancestry in modern human X chromosomes compared with that in modern human autosomes. By observing a 62% relative excess of AMH ancestry in Neanderthal X chromosomes, we characterized the interbreeding between the two groups as predominantly male Neanderthals with female AMHs. Analytic and numerical modeling presents mate preference as a more parsimonious cause of the sex bias than purely demographic processes with differential patterns of male and female migration.

Alexander Platt, Daniel N. Harris, and Sarah A. Tishkoff, "Interbreeding between Neanderthals and modern humans was strongly sex biased", 391 (6788) Science 922-925 (February 26, 2026).

While I don't dispute the genetic data that the study discloses and bases its narrative upon, I don't think that the narrative that the general audience presentation and even the study itself have chosen a narrative that is anything close to being the most plausible one.

I've previously discussed the narrative that I think is closer to the truth, using just the Y-DNA, mtDNA, and overall autosomal genetic data previously available, without the X chromosome specific data from both admixed modern humans and admixture in Neanderthal ancient DNA  that this study brings to the table. 

In a nutshell, my prior analysis was that admixed Neanderthal-modern human hybrid children ended up in the communities to which their mothers belonged, and that Haldane's rule (which provides as relevant to this context, that cross-species hybrids are disproportionately female, perhaps sometimes sterile males, and only rarely fertile males) was also a key factor in why there are no modern humans with Neanderthal Y-DNA, there is no Neanderthal ancient DNA with modern human Y-DNA, why there are no modern humans with Neanderthal mtDNA, and why there is no Neanderthal ancient DNA with modern human mtDNA.

I also suggests that hybrid children may have often been the product of rape or episodic hookups, rather than long term marriage-like relationships embedded in a modern human or a Neanderthal tribe.

While the X chromosome data may require some fine tuning of that analysis, I don't think that it justifies a wholesale paradigm shift from it. I think that the new study's narrative gives insufficient consideration of these priors from that data when evaluating when kind of narrative makes the most sense to interpret its X chromosome based data, and focusing on a sexual selection and attraction based narrative instead.

The default assumption of the simple, uniparental DNA driven paradigm with Haldane's law paradigm is that the X chromosome would have the same proportions of Neanderthal and modern human DNA as other chromosomes, since almost all of the fertile hybrid children would have one Neanderthal X chromosome and one modern human X chromosome.

Admixture in X chromosomes could be reduced in early modern human communities if they had an influx of "basal" modern human populations (i.e. introgression from modern humans with no Neanderthal admixture) and that introgression was female biased because the Neanderthal admixed population was usually (at least with its own species pairing in marriage-like ways) patrilocal and recruited brides from outside its tribe in a way that had a significant basal modern human component. This kind of marriage pattern was common in the Neolithic Age, the Bronze Age and the Iron Age, including in herder populations who were culturally more similar to ancestral modern human hunter-gatherer societies, so it is quite plausible.

The lack of modern human mtDNA in Neanderthal ancient DNA strongly constrains the extent to which the mothers of hybrid individuals in Neanderthal communities were modern humans, although the fact that Neanderthal effective populations were falling at the time of Neanderthal-modern human contact means that it would be easier to lose low frequency modern human mtDNA variants in Neanderthal communities than it would be to lose low frequency Neanderthal mtDNA variants in human communities.

But, one still has to explain the new data point that there is an excess of modern human DNA in the ancient DNA of admixed Neanderthal X chromosomes. But that data still has to be reconciled with the lack of modern human mtDNA in any Neanderthal ancient DNA.

Since the Neanderthal ancient DNA sample, unlike the modern human DNA sample, is a small one, the statistical significance of this excess also needs to be examined as well as possible selective genetic fitness based explanations for some of the modern human X chromosome excesses relative to Neanderthal genes at those loci. But the number of genes per chromosome is great enough and 62% is a significant enough excess, that statistical flukes probably don't explain that much of the excess.

The first possible explanation that comes to mind for the excess modern human genes in admixed Neanderthal ancient DNA is that the effective population size of Neanderthals in that era was much smaller than the effective population size of modern humans in that era. In other words, the Neanderthals were more inbred.

This would make children in Neanderthal communities with pure Neanderthal source X chromosomes more vulnerable to harmful X chromosome based recessive diseases than hybrid Neanderthal children who would enjoy hybrid fitness. Over time, at multiple generations and not just the first one, this would favor individuals in Neanderthal communities with hybrid ancestry over those with pure Neanderthal ancestry. And the effect would be strong on the X chromosome than on the other autosomal chromosomes, because Neanderthal boys would not be at risk of suffering from harmful X chromosome based recessive diseases, while unadmixed Neanderthal girls would be at risk of suffering from these diseases.

This factor alone, depending on the prevalence of X chromosome based recessive diseases in much more inbred Neanderthal gene pools, might very well have been enough to explain the excess of modern human X chromosomes in the ancient DNA of admixed Neanderthals, without requiring modern human woman who have hybrid children to frequently live in and raise their children in Neanderthal communities (leaving us with the problem of explaining why there is no modern human mtDNA in these admixed Neanderthal individuals in Neanderthal communities).

I'll update this post with more analysis as time permits, after I've had more time to read the paper and consider its analysis.

A Grammatical Gender And Ergativity Linguistics Refresher

Grammatical gender rules are not a feature that is shared by all Indo-European languages, or even a feature shared by all languages in the Germanic language family. 

Ergativity is is a grammatical feature with more uniformity, but is not uniform within the Indo-European or the Berber language family within the Afro-Asiatic language family.

Grammatical gender

Some of the Germanic languages (Icelandic, Norwegian, German, and Yiddish), the Slavic languages, and Greek have three grammatical genders (masculine, feminine, and neuter).

The subset of Germanic languages made up of Swedish, Danish, Dutch, and Flemish have a "common" and a neuter grammatical gender (the masculine grammatical gender and the feminine grammatical gender are merged relative to the three gender system).

The Celtic languages of the British Isles, the Romance languages, the Baltic languages (Lithuanian and Latvian), the Northern Kurdish languages, and the non-Indo-European Afro-Asiatic languages of Europe and the Mediterranean and the Middle East (Arabic including Maltese, Hebrew, Aramaic, the Berber languages, Coptic) have two grammatical genders (masculine and feminine). But, they don't have a neuter grammatical gender.

English (a Germanic language), the Central Kurdish languages, the non-Indo-European Uralic languages (Saami, Finnish, Estonian, and Hungarian), and the non-Indo-European Turkish languages do not have grammatical gender. Modern English, in common with Icelandic, Norwegian, and German does, however, have a masculine, feminine, and neuter third person singular pronoun (he, she, it), and Central Kurdish has a masculine and feminine but not neuter third person pronoun.

The Non-Indo-European Basque language has an animate noun class and an inanimate noun class that is called a grammatical gender, rather than an actually gender based grammatical gender system.

All of these languages are Indo-European language, except Basque, Turkish, the Uralic languages, the Afro-Asiatic languages (Arabic including Maltese, the Berber languages, and Hebrew).

Ergativity

Ergativity is another grammatical feature that doesn't strictly follow language family lines (probably due to substrate influences). Basque is ergative, as is Kurdish (which is spoken in an area where extinct ergative languages were once spoken), as are some Berber languages.

What is ergativity?

I'll quote the Wikipedia link above to make sure that I get it right:

In linguistic typology, ergative–absolutive alignment is a type of morphosyntactic alignment in which the subject of an intransitive verb behaves like the object of a transitive verb, and differently from the subject of a transitive verb. All known ergative languages show ergativity in their morphology, and a small portion also show ergativity in their syntax.

The ergative-absolutive alignment is in contrast to nominative–accusative alignment, which is observed in English, where the single argument of an intransitive verb behaves grammatically like the agent (subject) of a transitive verb but different from the object of a transitive verb. In ergative–absolutive languages with grammatical case, the case for the single argument of an intransitive verb and the object of a transitive verb is called the absolutive, and the case used for the agent of a transitive verb is called the ergative.

By one measure, 17% the world's languages use an ergative alignment in the marking of noun phrases. Examples of ergative-absolutive languages include Basque, Georgian, Mayan, Tibetan, Sumerian, and certain Indo-European languages such as Pashto, the Kurdish languages and many others.

Little Red Dots

 

The Higgs Boson Still Matches The Standard Model

The Standard Model Higgs Boson hypothesis continues to be a good fit to the data, this time, an inclusive measurement of all Higgs bosons produced in the LHC data of the CMS experiment over a three year period.

Combined measurements of Higgs boson production and decay rates are reported, representing the most comprehensive study performed by the CMS Collaboration to date. The included analyses use proton-proton collision data recorded by the CMS experiment at s√ = 13 TeV from 2016 to 2018, corresponding to an integrated luminosity of 138 fb−1. The statistical combination is based on analyses that measure the following decay channels: H → γγ, H → ZZ, H → WW, H → ττ, H → bb, H → μμ, and H → Zγ → ℓℓγ (ℓ = e,μ). Information in the events from each decay channel is used to target multiple Higgs boson production processes. Searches for invisible Higgs boson decays are also considered, as well as an analysis that measures off-shell Higgs boson production in the H → ZZ → 4ℓ decay channel. 

The best fit inclusive signal yield is measured to be 1.014 +0.055 −0.053 times the standard model expectation, for a Higgs boson mass of 125.38 GeV. 

Measurements in kinematic regions defined by the simplified template cross section framework are also provided, as well as interpretations in the coupling modifier and standard model effective field theory frameworks. The coupling modifier interpretation is further used to place constraints on various two-Higgs-doublet models. The results show good compatibility with the standard model predictions for the majority of the measured parameters.

CMS Collaboration, "Combined measurements and interpretations of Higgs boson production and decay in proton-proton collisions at s√ = 13 TeV" arXiv:2602.18611 (February 20, 2026) (Submitted to Reports on Progress in Physics).

The result is about 0.2 sigma above the Standard Model expectation, which is very consistent with the result obtained and once again suggests that the uncertainties in the measurement (the average discrepancy from the expected results if the errors are accurately measured and Gaussian should be 1 sigma), in the interests of being conservative in estimating them, are overestimated. This is common in electroweak (as opposed to strong force) high energy physics experiments.

The breakdown of the sources of uncertainty are notable too:

The theoretical uncertainty is the biggest contributor to the total uncertainty. More specifically:

The largest component of the uncertainty originates from the theoretical uncertainty in the signal yield normalization (∆µincl/µincl = 3.6%). The contributions from the experimental uncertainties are shared amongst the different sources of uncertainty, with no single dominant contribution.

The statistical uncertainty (assuming that the uncertainty can correctly be modeled as Gaussian, i.e. a statistical normal distribution) is almost certainly spot on correct because establishing it is a mechanical process that involves few judgment calls. This means that any excess estimates of uncertainty in this experiment come from the theoretical and systemic experimental uncertainties.

A statement about the Higgs boson mass used in this analysis is found in the introduction, and doesn't represent any insights from the inclusive measurement which doesn't meaningfully distinguish between the Higgs boson mass assumed in the analysis and newer more precise measurements by the ATLAS and CMS experiments which are about 0.2% (i.e. 170-200 MeV) less massive.

The SM predictions for the Higgs boson production and decay rates depend on the mass of the Higgs boson mH. For all measurements in this paper, the mass is fixed at mH = 125.38 GeV. This was the most precise measurement of m(H) (± 0.14 GeV) by the CMS Collaboration at the time that the analyses entering the combination were performed. Since then, a more precise measurement of m(H) = 125.08 ± 0.12 GeV has been performed by CMS in the H → ZZ → 4ℓ channel. The ATLAS Collaboration also performed a more precise measurement of m(H) = 125.11 ± 0.11 GeV, combining the H → ZZ → 4ℓ and H → γγ channels. The small difference in m(H) between these values has a negligible effect on the results in this paper.

So, any hope from the abstract that this experiment would also shed light on the Higgs boson mass has been dashed. 

The final point in the abstract about only a majority of the results being compatible with the Standard Model is explained as follows:

In contrast to the inclusive measurement, the per production process measurement shows a small tension with the SM, with a compatibility p-value of pSM = 0.02. This tension is mostly driven by µtH, for which an excess of 2.2 standard deviations above the SM expectation is seen. The µWH and µZH parameters are also measured to be larger than the SM expectations by approximately two standard deviations. The 68% CL intervals range from ±7.5% for µggH to ±39% for µtH, relative to their best fit values. 

The per decay channel measurement shows a better compatibility with the SM (pSM = 0.33). The largest deviations are observed in the µττ and µZγ parameters. However, these are still compatible with the SM expectations within the 95% CL intervals. The µγγ, µZZ, µWW, and µττ parameters are all measured with excellent precision, with 68% CL intervals of approximately ±10% relative to their best fit values. The µbb parameter is measured with a 68% CL interval of ±15%. This represents a significant improvement compared to the previous combined Higgs boson measurement by the CMS Collaboration (±21%), because of the newly added H → bb channels and updated H → bb input analyses. The parameters for the rarer decay channels, µµµ and µZγ, are measured with 68% CL intervals of ±37% and ±39%, respectively, relative to their best fit values.

The biggest deviations in particular channels are still only slight tensions and are expected due to the look elsewhere effect. 

The constraints on the Higgs boson self-coupling relative to the Standard Model expected value, kappa(A), which is a quite hard to measure property of the Higgs boson, are also very consistent with the Standard Model expectation, as shown in the chart below (with kappa(F) and kappa(V) reflecting scenarios where there are different couplings to fermions and vector bosons).

Quick Hits

* The Sumerians had different number words and symbols to count numbers of different kinds of things. So, for example, the word for five pieces of fruit would be different than the word for five logs.

* Egyptian pyramids were built as trapezoids and then cut down to pyramids with the left over rock used to make new pyramids.

* Reputedly, Emperor Basil II of the Byzantine Empire was cruel.

* The Anglo-Saxons kept slaves in the middle ages.

* According to Gerald of Wales ca. 1316 CE, at that time the Irish were predominantly herders.

* Harsh murder sentences for newborns killed or neglected in the throes of unattended child birth are still common today even though the death penalty is almost never sought now in these circumstances.

* The TYRP1 gene variant discovered in 2012, is the cause of blond hair in the Solomon Islands in Melanesia, which is a different gene than the one that causes blond hair in Europeans.

* Before 1480, India and Sri Lanka were nearly connected by a land bridge known as Adam’s Bridge.

* There were once oceans on Mars.

High-resolution orbital images of Mars' largest canyon reveal ancient river deltas, proving the Red Planet once held an ocean the size of Earth's Arctic.

New high-resolution imagery from the European Space Agency’s ExoMars Trace Gas Orbiter has provided the most definitive evidence to date that Mars was once a blue planet. Researchers at the University of Bern identified distinct fan-shaped sediment deposits in the southeast Coprates Chasma region, part of the massive Valles Marineris canyon system. These structures, remarkably similar to river deltas on Earth, all sit at a consistent elevation between 3,650 and 3,750 meters. This geological alignment points to one unmistakable conclusion: the presence of an ancient coastline where rivers once emptied into a vast, stable sea approximately 3.37 billion years ago.

While previous theories about Martian oceans relied on lower-resolution data, this study offers direct geomorphological proof of a shoreline. The findings suggest that a massive body of water, comparable in size to Earth’s Arctic Ocean, once covered the entirety of Mars’ northern hemisphere. Though today these ancient deltas are buried beneath wind-sculpted dust and dunes, their distinctive shapes remain preserved. This discovery drastically alters our view of Martian history; the existence of a planet-wide water cycle and a stable ocean suggests that the conditions necessary for life were not isolated occurrences but a global phenomenon.

Source: Argadestya, P., et al. "Geomorphological and sedimentological evidence of a coastline in Southeast Coprates Chasma." npj Space Exploration (2026).

* There are social octopi that build homes for themselves off the coast of Australia.

* This very little bugger ,who is part of this clade of animals (and more specifically this one) is kind of cute in a Disney monsters way. They are the most heat-tolerant complex animal known to science after tardigrades (or water bears), which are able to survive temperatures over 150 °C. They were discovered in 1980 off the Galapagos islands.

When they grow up, they look like this (the "fur" is a symbiotic species of bacteria):

* A photograph of the February 19, 2026 solar eclipse in Antarctica (not AI).

* Nature can be amazing (also not AI).

* In West Texas, ca. 4500 BCE, hunter-gatherers used non-returnable boomerang sticks for small game and atlatl to throw their carefully crafted spears further for big game.

A cache of ancient weapons, more than 6,000 years old, has been uncovered in a remote rock shelter in West Texas, offering one of the clearest pictures yet of early life in North America.

The discovery was made at the San Esteban rock shelter in the Big Bend region, an area known for its dry climate and rugged desert landscape. That dryness turned out to be a gift to archaeologists. Items that would normally rot away wood, leather bindings, plant fibers remained intact for thousands of years. Inside the shelter, researchers found a carefully stored hunting kit dating to around 4,500 B.C., including wooden spear shafts wrapped in leather, stone projectile points, and parts of atlatls, the spear-throwing tools that dramatically increased a hunter’s range and power.

An atlatl works like a lever, giving a thrown spear greater speed and force. With it, hunters could strike animals from distances that would otherwise be impossible with a simple hand throw. Tests and prior studies show these tools could send projectiles well over 100 feet with deadly accuracy. The craftsmanship seen in the newly uncovered pieces shows careful shaping, balance, and planning. These were not rough survival tools; they were refined hunting systems built by people who deeply understood their environment.

Researchers also identified curved wooden throwing weapons often described as straight or non-returning boomerangs. Unlike the returning boomerangs many people picture today, these were designed to fly straight and hit small game with strong impact. Their presence adds another layer to what appears to have been a well-organized toolkit, likely stored together for repeated use.

The San Esteban site has a long history of human occupation stretching back thousands of years. Findings from this latest excavation reinforce the idea that the Big Bend region was not a temporary stop for wandering groups but a place where people lived, adapted, and developed sophisticated survival strategies. The tools show planning, skill, and an ability to work with available materials in smart, efficient ways.

Archaeologists involved in the project say the discovery helps rewrite outdated ideas about early North American societies. These communities were not primitive in the way older textbooks sometimes suggested. They engineered effective hunting technology, understood animal behavior, and created tools built to last.

As research continues, scientists hope to learn more about how these weapons were used, how they were stored, and what they reveal about daily life 6,000 years ago. For now, the dry rock shelter in West Texas has delivered something rare: a direct, tangible connection to hunters who once stood in the same desert landscape, preparing their tools for the next expedition.

* Maize farmers in Peru’s Chincha Valley were fertilizing their crops with seabird poop as early as the year 1250 CE.

* According to this source:

Around 3,800 years ago, a magnitude-9.5 megaquake struck northern Chile's coast, creating the largest earthquake known in human history. The rupture extended roughly 620 miles along the fault line—longer than the devastating 1960 Valdivia earthquake—and generated tsunamis with waves reaching 66 feet that traveled 5,000 miles across the Pacific Ocean to New Zealand. Archaeologists discovered marine deposits, boulders, shells, and sea life displaced far inland in the Atacama Desert, along with toppled stone structures buried beneath tsunami sediment, all radiocarbon-dated to this single catastrophic event.

The disaster forced complete coastal abandonment. Communities that depended on the ocean for survival relocated inland, staying away from the coast for over 1,000 years—an extraordinary response that demonstrates the quake's devastating impact on human populations. Researchers now recognize this megathrust earthquake, caused when tectonic plates suddenly unlocked after building massive strain, as both the oldest discovered earthquake-tsunami disaster in the Southern Hemisphere and a critical warning for modern coastal populations across the Pacific.

* Every recorded earthquake worldwide, 2015 to 2025 (my source didn't cite a source).

 

Another Challenge To ΛCDM That Dispenses With Cosmological Inflation

I have no idea why it took almost two weeks from submission for this preprint to be released by arXiv.

Recent discoveries, e.g., by JWST and DESI, have elevated the level of tension with inflationary ΛCDM. For example, the empirical evidence now suggests that the standard model violates at least one of the energy conditions from general relativity, which were designed to ensure that systems have positive energy, attractive gravity and non-superluminal energy flows.  

In this Letter, we use a recently compiled Type Ia supernova sample to examine whether ΛCDM violates the energy conditions in the local Universe, and carry out model selection with its principal competitor, the Rh=ct universe. We derive model-independent constraints on the distance modulus based on the energy conditions and compare these with the Hubble diagram predicted by both ΛCDM and Rh=ct, using the Pantheon+ Type Ia supernova catalog. 

We find that ΛCDM violates the strong energy condition over the redshift range z⊂(0,2), whereas Rh=ct satisfies all four energy constraints. At the same time, Rh=ct is favored by these data over ΛCDM with a likelihood of ∼89.5% versus ∼10.5%. The Rh=ct model without inflation is strongly favored by the Type Ia supernova data over the currrent standard model, while simultaneously adhering to the general relativistic energy conditions at both high and low redshifts.

Namit Chandak, Fulvio Melia, Junjie Wei, "Model selection with the Pantheon+ Type Ia SN sample" arXiv:2602.15047 (February 5, 2026) (4 pages, accepted for publication in A&A Letters).

Grab Bag Physics Articles

It may be possible to increase the precision with which the top quark mass is measured by a factor of ten to an uncertainty of plus or minus 30 MeV at a next generation positron-electron collider.

Constraints from Big Bang Nucleosynthesis significantly constrain the possibility of heavy neutral leptons (i.e. basically heavy, sterile neutrinos), allowing for the possible parameter space to be constrained from both above and below, potentially making it possible to rule out these hypothetical particles entirely, and in the meantime, focusing the search for them.

The Big Picture In Astrophysics Research

It is more statistical than an analytic description of the most important scientific advances, but it is still a notable overview. Certainly, there is no room to dispute that there has been a surge in astrophysics papers.

Over the past few years, Astrophysics has experienced an unprecedented increase in research output, as is evident from the year-over-year increase in the number of research papers put onto the arXiv. As a result, keeping up with progress happening outside our respective sub-fields can be exhausting. While it is impossible to be informed on every single aspect of every sub-field, this paper aims to be the next best thing. 

We present a summary of statistics for every paper uploaded onto the Astrophysics arXiv over the past year - 2025. We analyse a host of metadata ranging from simple metrics like the number of pages and the most used keywords, as well as deeper, more interesting statistics like the distribution of journals to which papers are submitted, the most used telescopes, the most studied astrophysical objects including GW, GRB, FRB events, exoplanets and much more. We also indexed the authors' affiliations to put into context the global distribution of research and collaboration. 

Combining this data with the citation information of each paper allows us to understand how influential different papers have been on the progress of the field this year. Overall, these statistics highlight the general current state of the field, the hot topics people are working on and the different research communities across the globe and how they function. 

We also delve into the costs involved in publications and what it means for the community. We hope that this is helpful for both students and professionals alike to adapt their current trajectories to better benefit the field.

Rommulus Francis Lewis, Hetansh Shah, Amruth Alfred, "Astrophysics Wrapped 2025: Year-in-Review of Every Astrophysics arXiv Paper from 2025" arXiv:2602.12303 (February 11, 2026).