Physical Origins
Hominins on Sulawesi during the Early Pleistocene
Budianto Hakim et al.
Nature, forthcoming
Abstract:
The dispersal of archaic hominins beyond mainland Southeast Asia (Sunda) represents the earliest evidence for humans crossing ocean barriers to reach isolated landmasses. Previously, the oldest indication of hominins in Wallacea, the oceanic island zone east of Sunda, comprised flaked stone artefacts deposited at least 1.02 ± 0.02 million years ago (Ma) at Wolo Sege on Flores. Early hominins were also established on the oceanic island of Luzon (Philippines), as indicated by both stone artefacts and cut marks on faunal remains dating to between 777 and 631 thousand years ago (ka) at Kalinga. Moreover, fossils of extinct, small-bodied hominins occur on Flores (Homo floresiensis) and Luzon (Homo luzonensis). On Sulawesi, the largest Wallacean island, previous excavations revealed stone artefacts with a minimum age of 194 ka at the open site of Talepu in the Walanae Depression, long preceding the earliest known presence of modern humans (Homo sapiens) in the region (73–63 ka in Sunda). Here we show that stone artefacts also occur at the nearby site of Calio in fossiliferous layers dated to at least 1.04 Ma and possibly up to 1.48 Ma, using palaeomagnetic dating of sedimentary rocks and coupled Uranium-series (U-series) and electron-spin resonance (US–ESR) dating of fossil teeth. The discovery of Early Pleistocene artefacts at Calio suggests that Sulawesi was populated by hominins at around the same time as Flores, if not earlier.
The activity and expression of adenylosuccinate lyase were reduced during modern human evolution, affecting brain and behavior
Xiang-Chun Ju et al.
Proceedings of the National Academy of Sciences, 12 August 2025
Abstract:
Adenylosuccinate lyase (ADSL), an enzyme that is crucial for purine biosynthesis, carries an amino acid substitution that is present in almost all humans today but absent in Neandertals and Denisovans. This substitution reduces the stability of the enzyme, but what functional consequences it has are unknown. Here, we show that when introduced into mice, this substitution causes substrates of the enzyme to accumulate in amounts that correlate negatively with ADSL expression levels. In the brain, where the expression of the enzyme is low, the substitution results in particularly high substrate levels. When the behavior of the mice is analyzed, female mice expressing the modern human-like version of ADSL access water more efficiently for drinking than their wild-type littermates. In addition to the amino acid substitution, a haplotype in the ADSL gene occurs at a carrier frequency of >97% in present-day humans and exhibits evidence of positive selection. It is associated with less ADSL expression as well as with increased concentrations of succinyladenosine, one of the substrates of the enzyme, in cerebrospinal fluid. Thus, two genetic changes have reduced ADSL activity in human tissues since modern and archaic humans separated, affecting purine biosynthesis, particularly in the brain.
Wandering of the auroral oval 41,000 years ago
Agnit Mukhopadhyay et al.
Science Advances, April 2025
Abstract:
In the recent geological past, Earth’s magnetic field reduced to ~10% of the modern values and the magnetic poles shifted away from the geographic poles, causing the Laschamps geomagnetic excursion, about 41 millennia ago. The excursion lasted ~2000 years, with dipole strength reduction and tilting spanning 300 years. During this period, the geomagnetic field’s multipolarity resembled outer planets, causing rapid magnetospheric changes. To our knowledge, this study presents the first space plasma analysis of the excursion, linking the geomagnetic field, magnetospheric system, and upper atmosphere in sequence using feedback channels for distinct temporal epochs. A three-dimensional reconstruction of Earth’s geospace system shows that these shifts affected auroral regions and open magnetic field lines, causing them to expand and wander toward lower latitudes. These changes likely altered the upper atmosphere’s composition and influenced anthropological progress during that era. Looking through a modern lens, such an event would disrupt contemporary technology, including communications and satellite infrastructure.
A 12,800-year-old layer with cometary dust, microspherules, and platinum anomaly recorded in multiple cores from Baffin Bay
Christopher Moore et al.
PLoS ONE, August 2025
Abstract:
The Younger Dryas Impact Hypothesis (YDIH) posits that ~12,800 years ago Earth encountered the debris stream of a disintegrating comet, triggering hemisphere-wide airbursts, atmospheric dust loading, and the deposition of a distinctive suite of extraterrestrial (ET) impact proxies at the Younger Dryas Boundary (YDB). Until now, evidence supporting this hypothesis has come only from terrestrial sediment and ice-core records. Here we report the first discovery of similar impact-related proxies in ocean sediments from four marine cores in Baffin Bay that span the YDB layer at water depths of 0.5–2.4 km, minimizing the potential for modern contamination. Using scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) and laser ablation ICP-MS, we detect synchronous abundance peaks of metallic debris geochemically consistent with cometary dust, co-occurring with iron- and silica-rich microspherules (4–163 μm) that are predominantly of terrestrial origin with minor (<2 wt%) ET contributions. These microspherules were likely formed by low-altitude touchdown airbursts and surface impacts of comet fragments and were widely dispersed. In addition, single-particle ICP-TOF-MS analysis reveals nanoparticles (<1 μm) enriched in platinum, iridium, nickel, and cobalt. Similar platinum-group element anomalies at the YDB have been documented at dozens of sites worldwide, strongly suggesting an ET source. Collectively, these findings provide robust support for the YDIH. The impact event likely triggered massive meltwater flooding, iceberg calving, and a temporary shutdown of thermohaline circulation, contributing to abrupt Younger Dryas cooling. Our identification of a YDB impact layer in deep marine sediments underscores the potential of oceanic records to broaden our understanding of this catastrophic event and its climatological impacts.
High-resolution near-infrared data reveal Pazyryk tattooing methods
Gino Caspari et al.
Antiquity, forthcoming
Abstract:
The tattoos of the Pazyryk ice mummies are of paramount importance for the archaeology of Iron Age Siberia and are often discussed from a broad stylistic and symbolic perspective. However, deeper investigations into this cultural practice were hindered by the inaccessibility of quality data. Here, the authors use high-resolution, near-infrared data in conjunction with experimental evidence to re-examine the tools and techniques employed in Early Iron Age tattooing. The high-quality data allow for the previously unfeasible distinction of artist hands and enable us to put the individual back into the picture of a widespread but rarely preserved prehistoric practice.