The structure of the f0(980) scalar boson has been a mystery for decades.
A new study, however, appears to show that it is basically a quark-antiquark meson with a valance strange quark and anti-strange quark. In other words, it is strange quark quarkonia. The new study largely rules out tetraquark, meson molecule, and quark-antiquark-gluon hybrid particle alternatives.
Newtonian mechanics, Newtonian gravity, and Newton's observations about optics went unchallenged and unamended for about 250 years. Scientists and engineers still use them on a daily basis, despite knowing that general relativity, special relativity, and quantum mechanics limit the range of their applicability.
The laws of physics he invented are still taught in high school and freshman college level physics classes. He co-invented calculus, which is still taught in high school and freshman and sophomore level college classes (although the notation of the independent co-inventor of calculus, Leibniz, rather than his own clunky notation, is used today).
Not all parts of Newton's legacy were equally illustrious. He was also a Unitarian theologian and an alchemist, and devoted almost as much time in his life to those ultimately fruitless projects, as he did to science and mathematics. He was also a member of Parliament, ran the Royal Mint for many years, was knighted, and led the Royal Society for twenty-four years. He never married and is not reputed to have had any children.
(Source)
a,b, Putative migration routes of BSP inferred using pairwise FST values (a) and after removing the Zambian Lozi population from the analyses (b). Arrow colours correspond to north-western Bantu speakers 2 (NW-BSP 2; brown; one arrow between Cameroon and CAR), west-western Bantu speakers (WW-BSP; green), south-western Bantu speakers (SW-BSP; dark blue) and eastern Bantu speakers (E-BSP; red). c, Spatial visualization of effective migration rates (EEMS software) estimated with the masked Only-BSP dataset. log(m) denotes the effective migration rate on a log10 scale, relative to the overall migration rate across the habitat. Populations are coloured according to each Bantu-speaking linguistic group (brown, green, dark blue and red dots). d, GenGrad analysis using FST as the genetic distance for the admixture-masked BSP dataset. Hexagons of the grid were plotted with a colour scale representing the FST gradient (key).
The expansion of people speaking Bantu languages is the most dramatic demographic event in Late Holocene Africa and fundamentally reshaped the linguistic, cultural and biological landscape of the continent.
With a comprehensive genomic dataset, including newly generated data of modern-day and ancient DNA from previously unsampled regions in Africa, we contribute insights into this expansion that started 6,000–4,000 years ago in western Africa. We genotyped 1,763 participants, including 1,526 Bantu speakers from 147 populations across 14 African countries, and generated whole-genome sequences from 12 Late Iron Age individuals.
We show that genetic diversity amongst Bantu-speaking populations declines with distance from western Africa, with current-day Zambia and the Democratic Republic of Congo as possible crossroads of interaction.
Using spatially explicit methods and correlating genetic, linguistic and geographical data, we provide cross-disciplinary support for a serial-founder migration model. We further show that Bantu speakers received significant gene flow from local groups in regions they expanded into.
Our genetic dataset provides an exhaustive modern-day African comparative dataset for ancient DNA studies and will be important to a wide range of disciplines from science and humanities, as well as to the medical sector studying human genetic variation and health in African and African-descendant populations.
African populations speaking Bantu languages (Bantu-speaking populations (BSP)) constitute about 30% of Africa’s total population, of which about 350 million people across 9 million km2 speak more than 500 Bantu languages. Archaeological, linguistic, historical and anthropological sources attest to the complex history of the expansion of BSP across subequatorial Africa, which fundamentally reshaped the linguistic, cultural and biological landscape of the continent. There is a broad interdisciplinary consensus that the initial spread of Bantu languages was a demic expansion and ancestral BSP migrated first through the Congo rainforest and later to the savannas further east and south. However, debates persist on the pathways and modes of the expansion.Whereas most recent human expansions involved latitudinal movements through regions with similar climatic conditions, the expansion of the BSP is notable for its primarily longitudinal trajectory, traversing regions with highly diverse climates and biomes, including the highlands of Cameroon, central African rainforests, African savannas and arid south-western Africa.
We present the first measurement of the Weyl potential at four redshifts bins using data from the first three years of observations of the Dark Energy Survey (DES). The Weyl potential, which is the sum of the spatial and temporal distortions of the Universe's geometry, provides a direct way of testing the theory of gravity and the validity of the ΛCDM model. We find that the measured Weyl potential is 2.3σ, respectively 3.1σ, below the ΛCDM predictions in the two lowest redshift bins. We show that these low values of the Weyl potential are at the origin of the σ8 tension between Cosmic Microwave Background (CMB) measurements and weak lensing measurements. Interestingly, we find that the tension remains if no information from the CMB is used. DES data on their own prefer a high value of the primordial fluctuations, followed by a slow evolution of the Weyl potential. A remarkable feature of our method is that the measurements of the Weyl potential are model-independent and can therefore be confronted with any theory of gravity, allowing efficient tests of models beyond General Relativity.
The general theory of relativity (GR) has excelled in explaining gravitational phenomena at the scale of the solar system with remarkable precision. However, when extended to the galactic or cosmological scale, it requires dark matter and dark energy to explain observations. In our previous article arXiv:2308.04503, we've formulated a gravity theory based in Mach's principle, known as Machian gravity. We demonstrated that the theory successfully explains galactic velocity profiles without requiring additional dark matter components. In previous studies, for a selected set of galaxy clusters, we also showed its ability to explain the velocity dispersion in the clusters without extra unseen matter components. This paper primarily explores the mass profiles of galaxy clusters. We test the Machian Gravity acceleration law on two distinct sets comprising approximately 150 galaxy clusters sourced from various studies. We fitted the dynamic mass profiles using the Machian gravity model. The outcomes of our study show exceptional agreement between the theory and observational results.
A new study looks at genetics, archeology, and linguistics to explain linguistic diversity in pre-Columbian California.
Before the colonial period, California harboured more language variation than all of Europe, and linguistic and archaeological analyses have led to many hypotheses to explain this diversity.
We report genome-wide data from 79 ancient individuals from California and 40 ancient individuals from Northern Mexico dating to 7,400–200 years before present (BP). Our analyses document long-term genetic continuity between people living on the Northern Channel Islands of California and the adjacent Santa Barbara mainland coast from 7,400 years BP to modern Chumash groups represented by individuals who lived around 200 years BP.
The distinctive genetic lineages that characterize present-day and ancient people from Northwest Mexico increased in frequency in Southern and Central California by 5,200 years BP, providing evidence for northward migrations that are candidates for spreading Uto-Aztecan languages before the dispersal of maize agriculture from Mexico.
Individuals from Baja California share more alleles with the earliest individual from Central California in the dataset than with later individuals from Central California, potentially reflecting an earlier linguistic substrate, whose impact on local ancestry was diluted by later migrations from inland regions.
After 1,600 years BP, ancient individuals from the Channel Islands lived in communities with effective sizes similar to those in pre-agricultural Caribbean and Patagonia, and smaller than those on the California mainland and in sampled regions of Mexico.
The effort to discover a quantum theory of gravity is motivated by the need to reconcile the incompatibility between quantum theory and general relativity.
Here, we present an alternative approach by constructing a consistent theory of classical gravity coupled to quantum field theory. The dynamics is linear in the density matrix, completely positive and trace preserving, and reduces to Einstein's theory of general relativity in the classical limit. Consequently, the dynamics doesn't suffer from the pathologies of the semiclassical theory based on expectation values.
The assumption that general relativity is classical necessarily modifies the dynamical laws of quantum mechanics -- the theory must be fundamentally stochastic in both the metric degrees of freedom and in the quantum matter fields. This allows it to evade several no-go theorems purporting to forbid classical-quantum interactions.
The measurement postulate of quantum mechanics is not needed -- the interaction of the quantum degrees of freedom with classical space-time necessarily causes decoherence in the quantum system.
We first derive the general form of classical-quantum dynamics and consider realisations which have as its limit deterministic classical Hamiltonian evolution. The formalism is then applied to quantum field theory interacting with the classical space-time metric.
One can view the classical-quantum theory as fundamental or as an effective theory useful for computing the back-reaction of quantum fields on geometry. We discuss a number of open questions from the perspective of both viewpoints.
We consider two interacting systems when one is treated classically while the other system remains quantum. Consistent dynamics of this coupling has been shown to exist, and explored in the context of treating space-time classically.
Here, we prove that any such hybrid dynamics necessarily results in decoherence of the quantum system, and a breakdown in predictability in the classical phase space. We further prove that a trade-off between the rate of this decoherence and the degree of diffusion induced in the classical system is a general feature of all classical quantum dynamics; long coherence times require strong diffusion in phase-space relative to the strength of the coupling.
Applying the trade-off relation to gravity, we find a relationship between the strength of gravitationally-induced decoherence versus diffusion of the metric and its conjugate momenta. This provides an experimental signature of theories in which gravity is fundamentally classical.
Bounds on decoherence rates arising from current interferometry experiments, combined with precision measurements of mass, place significant restrictions on theories where Einstein’s classical theory of gravity interacts with quantum matter. We find that part of the parameter space of such theories are already squeezed out, and provide figures of merit which can be used in future mass measurements and interference experiments.
The Kangxi Emperor (r. 1661–1722) holds the record for having the most imperial consorts [in the Qing Dynasty] with 79, while the Guangxu Emperor (r. 1875–1908) holds the record for having the fewest, with one empress and two consorts—a total of just three imperial consorts.
Functionally, this system, somewhat like the Saudi Arabian monarchy's succession system, insured that the hereditary emperorship would not end for lack of an heir. It also provided a pool of potential heirs from which a worthy successor could be chosen, mitigating, although not entirely eliminating, the harm caused by the occasional "mad king".
The Scalar Field Dark Matter model has been known in various ways throughout its history; Fuzzy, BEC, Wave, Ultralight, Axion-like Dark Matter, etc.
All of them consist in proposing that the dark matter of the universe is a spinless field Φ that follows the Klein-Gordon (KG) equation of motion ◻Φ−dV/dΦ=0, for a given scalar field potential V. The difference between different models is sometimes the choice of the scalar field potential V.
In the literature we find that people usually work in the nonrelativistic, weak-field limit of the KG equation where it transforms into the Schrödinger equation and the Einstein equations into the Poisson equation, reducing the KG-Einstein system, to the Schrödinger-Poisson system.
In this paper, we review some of the most interesting achievements of this model from the historical point of view and its comparison with observations, showing that this model could be the last answer to the question about the nature of dark matter in the universe.
Wide binary stars are used to test the modified gravity called Scalar-Tensor-Vector Gravity or MOG. This theory is based on the additional gravitational degrees of freedom, the scalar field G=GN(1+α), where GN is Newton's constant, and the massive (spin-1 graviton) vector field ϕμ. The wide binaries have separations of 2-30 kAU. The MOG acceleration law, derived from the MOG field equations and equations of motion of a massive test particle for weak gravitational fields, depends on the enhanced gravitational constant G=GN(1+α) and the effective running mass μ. The magnitude of α depends on the physical length scale or averaging scale ℓ of the system. The modified MOG acceleration law for weak gravitational fields predicts that for the solar system and for the wide binary star systems gravitational dynamics follows Newton's law.
The sunspot number record covers over three centuries.These numbers measure the activity of the Sun. This activity follows the solar cycle of about eleven years.
In the dynamo-theory, the interaction between differential rotation and convection produces the solar magnetic field. On the surface of Sun, this field concentrates to the sunspots. The dynamo-theory predicts that the period, the amplitude and the phase of the solar cycle are stochastic.
Here we show that the solar cycle is deterministic, and connected to the orbital motions of the Earth and Jupiter. This planetary-influence theory allows us to model the whole sunspot record, as well as the near past and the near future of sunspot numbers. We may never be able to predict the exact times of exceptionally strong solar flares, like the catastrophic Carrington event in September 1859, but we can estimate when such events are more probable. Our results also indicate that during the next decades the Sun will no longer help us to cope with the climate change. The inability to find predictability in some phenomenon does not prove that this phenomenon itself is stochastic.
Nestled in the mountains of Northern India, is a 4-metre rotating dish of liquid mercury. Over a 10-year period, the International Liquid Mirror Telescope (ILMT) will survey 117 square degrees of sky, to study the astrometric and photometric variability of all detected objects. . . .
A perfect reflective paraboloid represents the ideal reference surface for an optical device to focus a beam of parallel light rays to a single point. This is how astronomical mirrors form images of distant stars in their focal plane. In this context, it is amazing that the surface of a liquid rotating around a vertical axis takes the shape of a paraboloid under the constant pull of gravity and centrifugal acceleration, the latter growing stronger at distances further from the central axis. The parabolic surface occurs because a liquid always sets its surface perpendicular to the net acceleration it experiences, which in this case is increasingly tilted and enhanced with distance from the central axis. The focal length F is proportional to the gravity acceleration g and inversely proportional to the square of the angular velocity ω. In the case of the ILMT, the angular velocity ω is about 8 turns per minute, resulting in a focal length of about 8m. Given the action of the optical corrector, the effective focal length f of the D=4m telescope is about 9.44m, resulting in the widely open ratio f/D∼2.4. In the case of the ILMT, a thin rotating layer of mercury naturally focuses the light from a distant star at its focal point located at ∼8m just above the mirror, with the natural constraint that such a telescope always observes at the zenith.Thanks to the rotation of the Earth, the telescope scans a strip of sky centred at a declination equal to the latitude of the observatory (+29◦21′41.4′′ for the ARIES Devasthal observatory). The angular width of the strip is about 22′, a size limited by that of the detector (4k×4k) used in the focal plane of the telescope. Since the ILMT observes the same region of the sky night after night, it is possible either to co-add the images taken on different nights in order to improve the limiting magnitude or to subtract images taken on different nights to make a variability study of the corresponding strip of sky. Consequently, the ILMT is very well-suited to perform variability studies of the strip of sky it observes. While the ILMT mirror is rotating, the linear speed at its rim is about 5.6km/hr, i.e., the speed of a walking person.
A liquid mirror naturally flows to the precise shape paraboloid shape needed because it is a liquid under these conditions. And, since its surface is always dynamically readjusting itself to this shape, rather than being fixed in place just once as a solid mirror would be, any slight imperfections in its surface that do deviate from its paraboloid shape don't stay in exactly the same place. Instead, distortions from slight imperfections in the shape of the liquid mirror average out over multiple observations of the same part of the sky, to an average shape at any one location that is much closer to perfect than a solid mirror cast ultra-precisely just once. Thus, a liquid mirror reduces one subtle source of potential systemic errors that can arise from slight imperfections in the mirror's shape at particular locations that recur every time a particular part of the sky is viewed when a solid mirror is used.
A new paper makes an re-analysis of existing data to determine the top quark pole mass. It comes up with:
which is consistent with, but at the low end of the range of the Particle Data Group's estimate based upon indirect cross-section measurements (bringing these into the same amount of precision as its direct measurements of the top quark mass):
The global LC&P relationship (i.e. that the sum of the squares of the fundamental SM particle masses is equal to the square of the Higgs vev, which is equivalent to saying that the sum of the SM particle Yukawas is exactly 1), which is about 0.5% less than the predicted value (2 sigma in top quark and Higgs boson mass, implying a theoretically expected top quark mass of 173,360 MeV and a theoretically expected Higgs boson mass of 125,590 MeV if the adjustments were proportioned to the experimental uncertainty in the LC&P relationship given the current global average measurements, in which about 70% of the uncertainty is from the top quark mass uncertainty and about 29% is from the Higgs boson mass uncertainty). . . .But, the LC&P relationship does not hold separately for fermions and bosons, which would be analogous in some ways to supersymmetry. This is only an approximate symmetry. The sum of the squares of the SM fundamental boson masses is more than half of the square of the Higgs vev by about 0.5% (3.5 sigma of Higgs boson mass, implying a theoretically expected Higgs boson mass of about 124,650 MeV), while the sum of the squares of the SM fundamental fermion masses is less than half of the square of the Higgs vev by about 1.5% (about 2.8 sigma of top quark mass, implying a theoretically expected top quark mass of about 173,610 MeV). The combined deviation from the LC&P relationship for both fermions and bosons independently is 4.5 sigma, which is a very strong tensions that is nearly conclusively ruled out. One wonders if the slightly bosonic leaning deviation from this symmetry between fundamental fermion masses and fundamental boson masses has some deeper meaning or source.
The result in this new paper, by largely corroborating direct measurements of the top quark mass at similar levels of precision, continues to favor a lower top quark mass than the one favored by LP&C expectations.
Earlier, lower energy Tevatron measurements of the top quark mass (where the top quark was discovered) supported higher values for the top quark mass than the combined data from either of the Large Hadron Collider (LHC) experiments do and was closely in line with the LP&C expectation.
But there is no good reason to think that both of the LHC experiments measuring the top quark mass have greatly understated the systemic uncertainties in their measurements (which combine measurements from multiple channels with overlapping but not identical sources of systemic uncertainty). Certainly, the LHC experiments have much larger numbers of top quark events to work with than the two Tevatron experiments measuring the top quark mass did, so the relatively low statistical uncertainties of the LHC measurements of the top quark mass are undeniably something that makes their measurements more precise relative to Tevatron.
Could This Hint At Missing Fundamental Particles?
If I were a phenomenologist prone to proposing new particles, I'd say that this close but not quite right fit to the LP&C hypothesis was a theoretical hint that the Standard Model might be missing one or more fundamental particles, probably fermions (which deviate most strongly from the expected values).
I'll explore some of those possibilities, because readers might find them to be interesting. But, to be clear, I am not prone to proposing new particles, indeed, my inclinations are quite the opposite. I don't actually think that any of these proposals is very well motivated.
In part, this is because I think that dark matter phenomena and dark energy phenomena are very likely to be gravitational issues rather than due to dark matter particles or dark energy bosonic scalar fields, I don't think we need need particles to serve that purpose. Dark matter phenomena would otherwise be the strong motivator for a beyond the Standard Model new fundamental particle.
I am being lenient in not pressing some of the more involved arguments from the data and theoretical structure of fundamental physics that argue against the existence of many of these proposed beyond the Standard Model fundamental particles.
This is so, even though the LP&C hypothesis is beautiful, plausible, and quite close to the experimental data, so it would be great to be able to salvage it somehow if the top quark mass and Higgs boson mass end up being close to or lower than their current best fit estimated values.
Beyond The Standard Model Fundamental Fermion Candidates
If the missing fermion were a singlet, LP&C would imply an upper bound on its mass of about 3 GeV.
This could be a good fit for a singlet sterile neutrino that gets its mass via the Higgs mechanism and then transfers its own mass to the three active neutrinos via a see-saw mechanism.
It could also be a good fit for a singlet spin-3/2 gravitino in a supersymmetry inspired model in which only the graviton, and not the ordinary Standard Model fermions and bosons have superpartners.
A largely sterile singlet gravitino, and a singlet sterile neutrino, have both been proposed as cold dark matter candidates and at masses under 3 GeV the bounds on their cross-sections of interaction (so that they could have some self-interaction or weak to feeble interaction with ordinary matter since purely sterile dark matter that only interacts via gravity isn't a good fit for the astronomy data) aren't as tightly constrained as heavier WIMP candidates. And, the constraints on a WIMP dark matter particle cross section of interaction from direct dark matter detection experiments gets even weaker fairly rapidly between 3 GeV and 1 GeV, which is what the LP&C conjecture would hint at if either the current best fit value for the top quark mass or the current best fit value for the Higgs boson mass were a bit light.
The LP&C conjecture isn't a useful hint towards (or against) a massive graviton, however, because the experimental bounds on those are on the order of 32 orders of magnitude or more too small to be discernible by that means.
If there were three generations of missing fermions, you'd expect them to have masses about two-thirds higher than the charged lepton masses, with the most massive one still close to 3 GeV, the second generation one at about 176 MeV, and the first generation one at about 0.8 MeV. But these masses could be smaller if the best fit values for the top quark mass and/or Higgs boson mass ended rising somewhat as the uncertainties in those measurements fall.
These masses for a missing fermion triplet might fit a leptoquark model of the kind that has been proposed to explain B meson decay anomalies. The experimental motivation for leptoquarks was stronger before the experimental data supporting violations of the Standard Model principle of charged lepton universality (i.e. that the three charged leptons have precisely the same properties except their masses) evaporated in the face of factors in the data analysis of the seemingly anomalous experimental results from B meson decays. But there are still some lesser and subtle anomalies in B meson decays that didn't go away with this improved data analysis that could motivate similar leptoquark models.
If there were two missing fermions of similar masses (or two missing fermion triplets with their sum of square masses dominated by the third-generation particle of each triplet), this would suggest a missing fundamental particle mass on the order of up to about 2 GeV each.
A model with two missing fermion triplets might make sense if there were two columns of missing leptoquarks, instead of one, just as there are two columns of quarks (up type and down type) and two columns of leptons (charged leptons and neutrinos), in the Standard Model.
We test Milgromian dynamics (MOND) using wide binary stars (WBs) with separations of 2−30 kAU. Locally, the WB orbital velocity in MOND should exceed the Newtonian prediction by ≈20% at asymptotically large separations given the Galactic external field effect (EFE).
We investigate this with a detailed statistical analysis of Gaia DR3 data on 8611 WBs within 250 pc of the Sun. Orbits are integrated in a rigorously calculated gravitational field that directly includes the EFE. We also allow line of sight contamination and undetected close binary companions to the stars in each WB. We interpolate between the Newtonian and Milgromian predictions using the parameter αgrav, with 0 indicating Newtonian gravity and 1 indicating MOND.
Directly comparing the best Newtonian and Milgromian models reveals that Newtonian dynamics is preferred at 19σ confidence. Using a complementary Markov Chain Monte Carlo analysis, we find that αgrav=−0.021+0.065−0.045, which is fully consistent with Newtonian gravity but excludes MOND at 16σ confidence. This is in line with the similar result of Pittordis and Sutherland using a somewhat different sample selection and less thoroughly explored population model.
We show that although our best-fitting model does not fully reproduce the observations, an overwhelmingly strong preference for Newtonian gravity remains in a considerable range of variations to our analysis.
Adapting the MOND interpolating function to explain this result would cause tension with rotation curve constraints. We discuss the broader implications of our results in light of other works, concluding that MOND must be substantially modified on small scales to account for local WBs.
The immense diversity of the galaxy population in the universe is believed to stem from their disparate merging histories, stochastic star formations, and multi-scale influences of filamentary environments. Any single initial condition of the early universe was never expected to explain alone how the galaxies formed and evolved to end up possessing such various traits as they have at the present epoch. However, several observational studies have revealed that the key physical properties of the observed galaxies in the local universe appeared to be regulated by one single factor, the identity of which has been shrouded in mystery up to date.
Here, we report on our success of identifying the single regulating factor as the degree of misalignments between the initial tidal field and protogalaxy inertia momentum tensors. The spin parameters, formation epochs, stellar-to-total mass ratios, stellar ages, sizes, colors, metallicities and specific heat energies of the galaxies from the IllustrisTNG suite of hydrodynamic simulations are all found to be almost linearly and strongly dependent on this initial condition, when the differences in galaxy total mass, environmental density and shear are controlled to vanish. The cosmological predispositions, if properly identified, turns out to be much more impactful on galaxy evolution than conventionally thought.
The earliest known dingo remains, found in Western Australia, date to 3,450 years ago. Based on a comparison of modern dingoes with these early remains, dingo morphology has not changed over thousands of years. This suggests that no artificial selection has been applied over this period and that the dingo represents an early form of dog. They have lived, bred, and undergone natural selection in the wild, isolated from other dogs until the arrival of European settlers, resulting in a unique breed.In 2020, an MDNA study of ancient dog remains from the Yellow River and Yangtze River basins of southern China showed that most of the ancient dogs fell within haplogroup A1b, as do the Australian dingoes and the pre-colonial dogs of the Pacific, but in low frequency in China today. The specimen from the Tianluoshan archaeological site, Zhejiang province dates to 7,000 YBP (years before present) and is basal to the entire haplogroup A1b lineage. The dogs belonging to this haplogroup were once widely distributed in southern China, then dispersed through Southeast Asia into New Guinea and Oceania, but were replaced in China by dogs of other lineages 2,000 YBP.The oldest reliable date for dog remains found in mainland Southeast Asia is from Vietnam at 4,000 YBP, and in Island Southeast Asia from Timor-Leste at 3,000 YBP. In New Guinea, the earliest dog remains date to 2,500–2,300 YBP from Caution Bay near Port Moresby, but no ancient New Guinea singing dog remains have been found. The earliest dingo remains in the Torres Straits date to 2,100 YBP.
The earliest dingo skeletal remains in Australia are estimated at 3,450 YBP from the Mandura Caves on the Nullarbor Plain, south-eastern Western Australia; 3,320 YBP from Woombah Midden near Woombah, New South Wales; and 3,170 YBP from Fromme's Landing on the Murray River near Mannum, South Australia.
Dingo bone fragments were found in a rock shelter located at Mount Burr, South Australia, in a layer that was originally dated 7,000-8,500 YBP. Excavations later indicated that the levels had been disturbed, and the dingo remains "probably moved to an earlier level."
The dating of these early Australian dingo fossils led to the widely held belief that dingoes first arrived in Australia 4,000 YBP and then took 500 years to disperse around the continent. However, the timing of these skeletal remains was based on the dating of the sediments in which they were discovered, and not the specimens themselves.In 2018, the oldest skeletal bones from the Madura Caves were directly carbon dated between 3,348 and 3,081 YBP, providing firm evidence of the earliest dingo and that dingoes arrived later than had previously been proposed. The next-most reliable timing is based on desiccated flesh dated 2,200 YBP from Thylacine Hole, 110 km west of Eucla on the Nullarbor Plain, southeastern Western Australia. When dingoes first arrived, they would have been taken up by indigenous Australians, who then provided a network for their swift transfer around the continent. Based on the recorded distribution time for dogs across Tasmania and cats across Australia once indigenous Australians had acquired them, the dispersal of dingoes from their point of landing until they occupied continental Australia is proposed to have taken only 70 years. The red fox is estimated to have dispersed across the continent in only 60–80 years.At the end of the last glacial maximum and the associated rise in sea levels, Tasmania became separated from the Australian mainland 12,000 YBP, and New Guinea 6,500–8,500 YBP by the inundation of the Sahul Shelf. Fossil remains in Australia date to around 3,500 YBP and no dingo remains have been uncovered in Tasmania, so the dingo is estimated to have arrived in Australia at a time between 3,500 and 12,000 YBP. To reach Australia through Island Southeast Asia even at the lowest sea level of the last glacial maximum, a journey of at least 50 kilometres (31 mi) over open sea between ancient Sunda and Sahul was necessary, so they must have accompanied humans on boats.
Some best estimates of Austronesian migration are as follows:
