In that long stretch of Earth’s history before it was supposedly "created," according to creationist mythology—a span covering 99.9975% of the planet’s existence—a remarkable geophysical event occurred. Around 41,000 years ago, during a time when modern humans, Neanderthals, and Denisovans coexisted in Eurasia, a major disturbance in Earth’s magnetic field likely influenced human behaviour and may have hastened the disappearance of the Neanderthals.
This event, known as the Laschamps Excursion, was not a typical magnetic pole reversal, which Earth undergoes roughly every 100,000 years. Instead, the planet's magnetic field entered a chaotic state, weakening dramatically to around 10% of its usual strength and breaking into multiple, unstable poles.
Earth’s magnetic field normally shields the surface from ionising radiation by deflecting much of it towards the poles. With that protective barrier severely weakened, the planet would have been exposed to much stronger levels of ultraviolet radiation. The usual deflection of charged particles also produces the auroras, which during this period would have appeared across much of the night sky, including at lower latitudes—perhaps even near the equator—due to the multiple and shifting magnetic poles.
Although the Laschamps Excursion lasted only a few years, the environmental changes it triggered may explain behavioural shifts visible in the archaeological record. This is discussed in an article in The Conversation by Raven Garvey, Associate Professor of Anthropology at the University of Michigan; Agnit Mukhopadhyay, Research Scholar at the University of Alberta and Research Affiliate at Michigan; and Sanja Panovska, a Research Scientist at the GFZ Helmholtz Centre for Geosciences. Together with their colleagues, they have published their findings—open access—in Science Advances.
Incidentally, the archaeological evidence discussed here should not exist at all if the biblical flood narrative were true. Such a flood would have obliterated or buried this material beneath a chaotic layer of silt, destroying the stratified layers of sediment by which these finds are reliably dated—dating that is wholly inconsistent with the timeline of human history as derived from biblical mythology. Moreover, the Laschamps Excursion undermines any creationist claim that the Earth was created and fine-tuned especially for human life. If something as fundamental as magnetic polarity—and the UV protection it affords—can fail naturally due to processes in Earth’s core, then the idea of a specially designed planet collapses under its own absurdity.
The article from The Conversation is reproduced below under a Creative Commons licence and has been reformatted for stylistic consistency.
Weird space weather seems to have influenced human behavior on Earth 41,000 years ago – our unusual scientific collaboration explores how
Wandering magnetic fields would have had noticeable effects for humans.
Raven Garvey, University of Michigan; Agnit Mukhopadhyay, University of Michigan, and Sanja Panovska, GFZ Helmholtz Centre for GeosciencesMaximilian Schanner (GFZ Helmholtz Centre for Geosciences, Potsdam, Germany)
Our first meeting was a bit awkward. One of us is an archaeologist who studies how past peoples interacted with their environments. Two of us are geophysicists who investigate interactions between solar activity and Earth’s magnetic field.
When we first got together, we wondered whether our unconventional project, linking space weather and human behavior, could actually bridge such a vast disciplinary divide. Now, two years on, we believe the payoffs – personal, professional and scientific – were well worth the initial discomfort.
Our collaboration, which culminated in a recent paper in the journal Science Advances, began with a single question: What happened to life on Earth when the planet’s magnetic field nearly collapsed roughly 41,000 years ago?
Weirdness when Earth’s magnetic shield falters
This near-collapse is known as the Laschamps Excursion, a brief but extreme geomagnetic event named for the volcanic fields in France where it was first identified. At the time of the Laschamps Excursion, near the end of the Pleistocene epoch, Earth’s magnetic poles didn’t reverse as they do every few hundred thousand years. Instead, they wandered, erratically and rapidly, over thousands of miles. At the same time, the strength of the magnetic field dropped to less than 10% of its modern day intensity.
So, instead of behaving like a stable bar magnet – a dipole – as it usually does, the Earth’s magnetic field fractured into multiple weak poles across the planet. As a result, the protective force field scientists call the magnetosphere became distorted and leaky.
The magnetosphere normally deflects much of the solar wind and harmful ultraviolet radiation that would otherwise reach Earth’s surface.
So, during the Laschamps Excursion when the magnetosphere broke down, our models suggest a number of near-Earth effects. While there is still work to be done to precisely characterize these effects, we do know they included auroras – normally seen only in skies near the poles as the Northern Lights or Southern Lights – wandering toward the equator, and significantly higher-than-present-day doses of harmful solar radiation.
Aurors in the skies above Europe could have been breathtaking, terrifying or both for ancient humans.
The archaeologist’s answer was absolutely.
Human responses to ancient space weather
For people on the ground at that time, auroras may have been the most immediate and striking effect, perhaps inspiring awe, fear, ritual behavior or something else entirely. But the archaeological record is notoriously limited in its ability to capture these kinds of cognitive or emotional responses.
Researchers are on firmer ground when it comes to the physiological impacts of increased UV radiation. With the weakened magnetic field, more harmful radiation would have reached Earth’s surface, elevating risk of sunburn, eye damage, birth defects, and other health issues.
In response, people may have adopted practical measures: spending more time in caves, producing tailored clothing for better coverage, or applying mineral pigment “sunscreen” made of ochre to their skin. As we describe in our recent paper, the frequency of these behaviors indeed appears to have increased across parts of Europe, where effects of the Laschamps Excursion were pronounced and prolonged.
Naturally occurring ochre can act as a protective sunscreen if applied to skin.
Importantly, we’re not suggesting that space weather alone caused an increase in these behaviors or, certainly, that the Laschamps caused Neanderthals to go extinct, which is one misinterpretation of our research. But it could have been a contributing factor – an invisible but powerful force that influenced innovation and adaptability.
Cross-discipline collaboration
Collaborating across such a disciplinary gap was, at first, daunting. But it turned out to be deeply rewarding.
Archaeologists are used to reconstructing now-invisible phenomena like climate. We can’t measure past temperatures or precipitation directly, but they’ve left traces for us to interpret if we know where and how to look.
An artistic rendering of how far into lower latitudes the aurora might have been visible during the Laschamps Excursion.
Maximilian Schanner (GFZ Helmholtz Centre for Geosciences, Potsdam, Germany)
Likewise, geophysicists, who typically work with large datasets, models and simulations, may not always engage with some of the stakes of space weather. Archaeology adds a human dimension to the science. It reminds us that the effects of space weather don’t stop at the ionosphere. They can ripple down into the lived experiences of people on the ground, influencing how they adapt, create and survive.
The Laschamps Excursion wasn’t a fluke or a one-off. Similar disruptions of Earth’s magnetic field have happened before and will happen again. Understanding how ancient humans responded can provide insight into how future events might affect our world – and perhaps even help us prepare.
Our unconventional collaboration has shown us how much we can learn, how our perspective changes, when we cross disciplinary boundaries. Space may be vast, but it connects us all. And sometimes, building a bridge between Earth and space starts with the smallest things, such as ochre, or a coat, or even sunscreen.
Raven Garvey, Associate Professor of Anthropology, University of Michigan; Agnit Mukhopadhyay, Research Scholar at University of Alberta; Research Affiliate, University of Michigan, and Sanja Panovska, Research scientist, GFZ Helmholtz Centre for Geosciences
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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.
INTRODUCTION
For over 3.2 billion years, Earth’s intrinsic magnetic field has protected the planet’s atmosphere (1) and habitability (2) by serving as a shield against the solar wind (3), a continuous stream of energetic charged particles emanating from the Sun. This shield, known as the magnetosphere (4), takes on a shape resembling a magnetic dipole and is shaped by convective flow processes (5) and currents carrying charged particles (6). Within the magnetosphere, magnetic field lines transport charged particles by trapping and/or accelerating them, creating a space plasma environment (7, 8) that spans tens to hundreds of Earth radii (RE; ~6378 km in distance units) in the dayside and nightside, respectively. Earth’s space plasma environment is a complex and nonlinear system that plays a crucial role in safeguarding life from space-based threats (9). Charged particles from this environment interact with the upper atmosphere near the magnetic poles, giving rise to the captivating natural light displays known as the aurora borealis (Northern Lights) and aurora australis (Southern Lights) (10). Because of their close association with the planet’s intrinsic magnetic field, the attributes of the aurora are directly affected by magnetic disturbances like space storms (11), and magnetic substorms (12, 13). These disturbances can alter the trajectories of charged particles, affecting the location and intensity of the aurorae (14). Beyond shielding Earth from the solar wind, the space plasma environment also safeguards the planet’s habitability by deflecting harmful solar charged particles and cosmic radiation (15), thereby preserving the integrity of the stratospheric ozone layer (16) and atmospheric circulation processes (17). Furthermore, this magnetic environment plays a critical role in protecting modern technology like satellites (18), communication channels (19), and electrical power grids (20) during such disturbances, underscoring its profound societal importance.
Despite serving as a protective shield, Earth’s intrinsic magnetic field is prone to fluctuations. Owing to its convecting liquid outer core (21), which drives the planetary dynamo (22), the intrinsic magnetic field has constantly varied in geological time (23), occasionally leading to a complete reversal of the field (24). On certain occasions, the geomagnetic field changes rapidly over the time span of a few millennia; these events are called geomagnetic excursions (25) (henceforth referred to as excursions). Excursions are similar to geomagnetic reversals but occur over shorter timescales (24). They cause the intrinsic field strength to diminish and the magnetic tilt to change (25), rapidly relocating the magnetic poles over vast distances, even within a human lifetime (26). By contrast, the duration of the most recent reversal, Matuyama-Brunhes reversal, is estimated to be in the order of 20 to 30 thousand years (27). Although the exact circumstances that cause an excursion are not clearly established (23, 24), geomagnetic records indicate that the Earth’s magnetic field changed markedly about 41,000 years ago (or 41 ka). This event, known as the Laschamps excursion, is the most recent, well-documented, and best-studied global excursion, having been observed in several geological archival records worldwide (28). During this event, the axial dipole components of Earth’s geomagnetic field substantially weakened, resulting in a significant reduction in field intensity and a departure from dipolarity (29).
The variations observed in Earth’s magnetic field during the Laschamps excursion would have had profound implications on Earth’s biosphere (30). The weakening magnetic field intensity likely led to an influx of energetic particles and cosmic radiation penetrating Earth’s atmosphere (31), potentially causing notable alterations in atmospheric circulation (14) and composition (32). Although it is widely believed that these variations had a direct impact on early human development with the emergence of modern humans and megafaunal extinctions being recorded during the same time period as this excursion (26), such assumptions were based on oversimplified models of the space plasma environment. Accurately assessing their impact remains challenging without a comprehensive reconstruction of the space plasma environment on a global scale. A previous study (33) has attempted to delineate Earth’s magnetospheric morphology and its effect on the upper atmosphere and aurora for nondipolar geomagnetic fields, albeit relying on synthetic data with idealized parameters. Until recently, only a limited number of studies (34) have explored the state of the near-Earth space environment concerning transient nondipolar geomagnetic fields. Although these studies provide insights into the effects of geomagnetic reversals on the magnetosphere, the specific conditions of the magnetosphere and aurorae during the Laschamps event have never been investigated until now.
To our knowledge, this manuscript presents the first study that delves into the global repercussions of the fluctuating intrinsic magnetic field on Earth’s magnetospheric structure during the Laschamps event, linking this structure to the formation of a wandering auroral zone. Recent progress in numerical modeling has allowed us to accurately investigate the geospace system not only in three dimensions but also as a collective system. The study breaks down the timeline of the Laschamps excursion into specific temporal epochs that reveal notable variations in the space environment while enabling easy comparisons of variability across different time frames. Moreover, correlating the geophysical findings with anthropological evidences offers a pathway for future research to delve deeper into the precise effects of geomagnetic fluctuations not only on Earth but also on Earth-like planets in distant stellar systems.
GEOMAGNETIC VARIATIONS DURING THE LASCHAMPS EXCURSION
Recent studies examining the multimillennial variations of Earth’s magnetic field have yielded remarkable insights into the overarching morphology of the Laschamps excursion, suggesting that its genesis lay in the decay and subsequent recovery of the axial dipole field’s influence on the geomagnetic field (29, 35). Studies indicate that the magnitude of the axial dipole field, the field component allowing Earth to have a dipole-like magnetic field structure, directly dictated the scale of the excursion, whether it was regional or global in scope (36). Although the field intensity was globally very low, reconstructions of spatial morphology showed that regional field intensities and directions differed strongly (22). Notably, the equatorial dipole and nondipole components of the field remained relatively stable amidst these fluctuations (36).
The Laschamps excursion persisted for roughly 1800 years at the Earth’s surface, and a deeper investigation into the core-mantle boundary across an extended time frame of the event (50 to 30 ka; see Fig. 1A) revealed three distinct periods: pre-Laschamps period (50 to 43 ka), the excursion period (42 to 40 ka), and post-Laschamps period (39 to 30 ka) (36). In the pre-Laschamps period, the geomagnetic field resembled the present-day configuration, dominated by a strong axial dipole field with high dipole moment values. However, during the excursion period, the axial dipole field weakened substantially, approaching near-zero levels and occasionally even reversing its polarity for geologically brief periods. Globally, the field intensity plummeted to levels lower than the contemporary field intensity observed over the South Atlantic Anomaly (37), the region with the weakest magnetic field strength on present-day Earth. Transitional directional changes in the field were observed worldwide, albeit with varying magnitudes and timings across different regions. Meanwhile, the nondipole field components remained relatively consistent with pre-Laschamps levels. In the post-Laschamps period, whereas the nondipole field continued to behave typically, the axial dipole field began a slow recovery. However, this recovery failed to fully restore the pre-Laschamps levels, resulting in frequent, regionally confined excursions (36) until the modern-day field intensity was attained (24, 28). This study focuses its geomagnetic analyses on the period encompassing the peak drop during the Laschamps event, honing in on the excursion state and the brief intervals immediately preceding and following it (see Fig. 1A, inset). Within the 42- to 39-ka time frame, three distinct phases were evident: the stable field before the extreme decay (Phase A), the Laschamps midpoint (Phase B), and the recovery (Phase C).
Fig. 1. Variations in Earth’s internal magnetic field during the Laschamps Event.
(A) Intensity (denoted as “magnetic intensity”) and directional variations (denoted as “magnetic inclination”) of the intrinsic magnetic field during the Laschamps excursion, in comparison to modern conditions. B.P., before the present. (B to F) Global maps of intensity and inclination at the Earth’s surface for selected epochs across the peak field intensity drop during Laschamps as identified in subplot (A).
The differences in the geomagnetic field during the three phases of the Laschamps excursion have been illustrated in Fig. 1 (B to F). Phase A signified a dipole-dominated field with a gradual decline in the dipole moment strength that reached approximately half of present-day values (38). Concurrently, as estimated from the dipole components (the first three Gauss coefficients of the geomagnetic field) (39), the dipole tilt underwent large deviations from the geographic poles to equatorward latitudes (∼15°; see Fig. 1B). Phase B witnessed the field intensity plummeting to its nadir, with the dipole moment plummeting to approximately an order of magnitude lower than present-day levels (∼10% of the modern dipole moment), alongside rapid and pronounced variations in dipole tilt (see Fig. 1C). These tilt fluctuations stemmed from the reduced axial dipole contribution, resulting in a complex field marked by the emergence of multiple poles, contrasting starkly with a simplistic dipole model (see Fig. 1, D and E). Phase C heralded the beginning of field intensity recovery to moderate levels, with dipole tilt gradually reaching present-day norms. Throughout much of this phase, the field adopted a dipole structure reminiscent of the modern-day configuration (see Fig. 1F). Nevertheless, although the dipole moment at 39.9 ka is similar to that of the pre-Laschamps epoch, discernible differences in the global geomagnetic structure between these two periods were evident, as illustrated by the isoclinic lines on both maps.
RESPONSE OF THE MAGNETOSPHERIC SYSTEM
Variations in intrinsic magnetic fields have considerable ramifications on a planet’s magnetospheric system. Comparisons between Earth’s magnetosphere and those observed in other planets within the solar system like Jupiter and Neptune show significant disparities in size and structure, primarily attributed to variations in planetary magnetic moments and rotation periods (40, 41). Thus, it is virtually certain that the notable fluctuations observed in the geomagnetic field during the Laschamps excursion would have triggered a marked transformation in Earth’s magnetospheric configuration. Recent investigations into Earth’s magnetospheric structure during the Matuyama-Brunhes reversal—the most recent geomagnetic reversal that took place 778 ka—uncovered a substantial reduction in the magnetosphere’s size and the emergence of numerous regions where the magnetic field lines interact and release energy over a period spanning multiple millenia (34). However, because of the accelerated pace of geomagnetic instability characteristic of an excursion, Earth’s magnetospheric configuration transformed profoundly and swiftly over the course of a few centuries during the Laschamps excursion. Leveraging advanced techniques rooted in first principles–based global-scale numerical schemes, we present a three-dimensional (3D) reconstruction of Earth’s prehistoric magnetosphere during the Laschamps excursion and analyze the system’s shape, size, and structure.
Figure 2 illustrates the swift variations in Earth’s magnetospheric structure across distinct temporal epochs, spanning the various phases of the Laschamps excursion. During much of Phase A of the excursion, Earth’s magnetospheric structure remained largely dipolar, resembling modern times (see comparisons of Fig. 2, A and B). However, a gradual decrease in geomagnetic strength resulted in a reduction in the magnetosphere’s size. By 42.153 ka, Earth’s magnetosphere shrunk to ∼5.3 RE (33,804 km from Earth’s surface) on the dayside, almost half the size of the present-day magnetosphere, which ranges between 8 and 11 RE (∼51,000 to 70,000 km from Earth’s surface) during moderate solar conditions (42). Diminishing geomagnetic strength also expanded the open-closed field line boundary around the poles. The open-closed field line boundary is a region characterized as a boundary between open geomagnetic field lines, magnetic field lines that extend from the magnetosphere into interplanetary space and facilitate the entry of energetic particles from the Sun (43) and galactic cosmic radiation (44), and closed geomagnetic field lines, looped field lines that connect back to the planetary magnetic field (45). Furthermore, a gradual increase in the geomagnetic field’s dipole tilt meant that the magnetosphere’s dipole axis was significantly inclined toward the equator. During this epoch, the magnetosphere tilted by 46.3° to the geographic polar axis, at least four times higher than modern Earth’s geomagnetic tilt of ∼11°. By 41.168 ka (see Fig. 2C), as Phase A of the excursion drew to a close, a weakening axial dipole field caused Earth’s magnetosphere to exhibit strong nondipolar characteristics. The dipole axis was severely tilted to the geographic axis by 76°, resulting in a magnetospheric configuration that resembled those observed in outer planetary systems like Neptune (46). Although still displaying dipolar features like a dayside bow shock (47) and a compressed magnetosheath region (48), the substantial geomagnetic tilt resulted in the open-closed field line boundary relocating near the dayside equatorial magnetospheric boundary. This peculiar magnetic arrangement has been further visualized through 3D snapshots of the prehistoric magnetosphere provided in the Supplementary Materials.
Fig. 2. Reconstructed magnetospheric configurations across successive temporal epochs during the Laschamps excursion.
(A) Present-day magnetosphere at Earth. (B to F) Magnetospheric morphologies in the x-z plane (geocentric solar ecliptic coordinates) for temporal epochs spanning the various phases of Laschamps, as delineated in Fig. 1. All configurations were reconstructed under moderately southward solar wind driving conditions at 00:00 UT. White lines trace magnetic field lines, whereas the background contour represents the plasma particle pressure values saturated at 1.5 nPa.
Phase B marked the excursion’s peak alterations to Earth’s magnetospheric structure. By 40.977 ka, the axial dipole strength during this phase was only about 10% of present-day levels. Consequently, the magnetosphere contracted in size, as depicted in Fig. 2D, with the magnetopause—the magnetic boundary of the magnetosphere in the dayside—reaching a meager 2.43 RE (15,498 km) from Earth’s surface. On the nightside, the magnetospheric field lines were restricted to ∼32.3 RE. This phase also gave rise to powerful nondipolar characteristics. Multiple weak magnetic poles emerged around various geographic locations, as illustrated in fig. S4. These poles created clusters of closed field lines that did not extend beyond ∼2 RE (12,700 km from Earth’s surface) on both the dayside and the nightside, whereas substantial interactions between open field lines were observed. By 40.531 ka, despite a muted dipole strength (∼19% of modern values), the magnetosphere started to show signs of recovery (see Fig. 2E), with a stronger dayside and nightside closed field line region and a discernible bow shock and magnetosheath region against the upstream solar wind. Notably, the dipole tilt was higher during this epoch, offset by the emergence of nondipolar configurations near the southern geographic pole, leading to a further broadening of the open-closed field line boundary.
As Phase C unfolded and geomagnetic conditions began to recover, Earth’s magnetosphere gradually reverted to its dipolar state (Fig. 2F). By 39.9 ka, the dipole tilt had nearly returned to modern levels (∼10°), albeit with a weaker dipole strength. This resulted in a magnetospheric configuration reminiscent of the pre-Laschamps era yet with a smaller dayside presence and an expanded open field line region near the poles. Notably, closed field line regions expanded on both the dayside and nightside, whereas the bow shock and dayside magnetospheric boundary pushed sunward, extending to 6.4 RE (40,820 km). Simultaneously, the nightside magnetosphere enlarged compared to earlier phases (see fig. S5). Toward the latter part of Phase C, there were no notable changes in the dipole tilt angle. Over the subsequent 10,000 years, as the geomagnetic field regained its pre-Laschamps dipole strength, the magnetosphere likely maintained an enlarged open field line region around the poles before gradually shrinking back to the present-day auroral zone.
GEOLOGICALLY RAPID WANDERING OF THE AURORAL OVAL
The Earth’s magnetosphere is constantly interacting with the solar wind, a stream of charged particles emanating from the surface of the Sun. This dynamic interaction results in the alignment of charged particles with Earth’s magnetic field, which are accelerated in the magnetosphere to precipitate into the upper reaches of the atmosphere (∼110 km). These charged particles, upon collision with neutral atoms within Earth’s atmosphere (9), ignite the ethereal display known as the aurorae or the Northern/Southern Lights. Primarily concentrated around the geomagnetic poles, the aurora finds its most pronounced manifestation near the delineating boundary between zones characterized by open and closed field lines (45). In doing so, it forms a ring-shaped contour surrounding the geomagnetic poles, commonly referred to as the auroral oval. Variations in magnetospheric shape and structure instigate the auroral oval in both the Northern Hemisphere and Southern Hemisphere to fluctuate. In modern times, the auroral oval’s location, structure, and intensity have been frequently affected by varying solar activity during space weather events (49). Space weather studies primarily focus on variations in Earth’s magnetosphere driven by changes in solar wind input to a relatively stable Earth’s magnetic field. In contrast, this study examines variations in Earth’s geomagnetic field under near-constant solar conditions. Building on the magnetospheric variations in the previous section, two substantive changes occurred in the aurora during the Laschamps excursion:
1) With the reduction in geomagnetic dipole moment, the magnetosphere was more compressed. This resulted in the expansion of the polar region encompassed by open field lines and resulted in the subsequent expansion of the aurora (26).
2) Rapid variations in the dipole tilt angle over a few centuries enabled the geomagnetic poles to be severely inclined, causing the location of the open-closed field line boundary and, by extension, the auroral oval to wander across the globe.
Figure 3 illustrates the transformative shifts across the Northern Hemisphere and Southern Hemisphere auroral zones during the excursion. The contoured rows within the figure delineate the auroral energy fluxes, quantifying the sheer magnitude of energy input from energetic charged particles at a distance of 1.5 RE (equivalent to 10,000 km) from Earth’s surface. Concurrently, the approximate positions of the auroral oval and the open-closed field line boundary are mapped at a height of 110 km above Earth’s surface in the subsequent row.
Fig. 3. Visualization of auroral charged particle energy flux variations and corresponding auroral zone wandering during the Laschamps excursion.
Subplots (A to E) depict auroral coverage in the Northern Hemisphere at specified temporal epochs as identified in Fig. 1, whereas subplots (F to J) showcase auroral coverage in the Southern Hemisphere during the same epochs. (Top projection in each subplot) Auroral energy flux contours are represented at 1.5 RE (10,000 km), with values saturated at 10 mW/m2. (Bottom projection in each subplot) The auroral oval (light green) and aggregate open field line zones (dark green) are projected at atmospheric altitudes (110 km) for each epoch, displayed over an orthographic globe projection. Red lines indicate the trajectory of the geomagnetic poles, based on the axial dipole tilt.
As the geomagnetic dipole underwent a simultaneous weakening and tilting during Phase A, the Northern Hemisphere’s auroral oval traversed from the Arctic region through Western Eurasia to Northern Africa, extending further to Northwestern Sahara. Similarly, in the Southern Hemisphere, the auroral oval shifted from the Antarctic sector toward the eastern expanse of Australia and New Zealand. Notably, the open field line region and the auroral oval underwent a substantial expansion, with the auroral poleward boundary broadening from an average diameter of 5610 km at 42.153 ka to an impressive 8167 km at 41.168 ka. For reference, the modern auroral oval has a diameter of <3000 km during nominal solar wind conditions. During Phase B, this expansion intensified significantly, propelled by the drastic reduction in the axial dipole strength and escalating influence of the nondipolar field. Despite a relatively reduced tilt in the oval, vast expanses of both hemispheres were enveloped by expansive open field line regions, unleashing a substantial barrage of auroral precipitation on a global scale. In modern space weather, extreme events can cause the oval region to expand, but only by a fraction of what occurred during the peak reduction in dipole strength. This epoch witnessed a monumental expansion and the probable fragmentation of the auroral oval, attributable to the nondipolar components of the geomagnetic field. As illustrated in Fig. 3C, the aurora assumed a global presence, engulfing sizeable regions of the Earth with both open and closed field lines, thus sculpting a near-Earth space environment unparalleled in history or during any contemporary space weather phenomenon. This anomalous auroral morphology began its gradual restitution by 40.531 ka, marking the onset of Phase C. The protracted progression of globally unstable auroral zones likely persisted for several centuries until, by 39.9 ka, the Earth’s axial dipole reasserted its dominance, confining the aurora to the polar regions, as is the case today.
Agnit Mukhopadhyay et al.
Wandering of the auroral oval 41,000 years ago.
Sci. Adv. 11, eadq7275(2025). DOI:10.1126/sciadv.adq7275
Copyright: © 2025 The authors.
Published by American Association for the Advancement of Science. Open access.
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
The authors present compelling evidence linking observable changes in the palaeontological record—specifically in human behaviour—to the geophysical disruption of Earth’s magnetic polarity known as the Laschamps Excursion. The very existence of this palaeontological and geophysical evidence stands in stark contrast to the creationist belief in the Bible as an inerrant account of Earth's history and life upon it.
Far from supporting the notion of a stable, perfectly designed planet fine-tuned for human life and created ex nihilo just a few thousand years ago, findings like these reveal a picture of humanity shaped by environmental pressures on a dynamic—and at times hostile—planet. The overwhelming weight of evidence exposes the biblical narrative as the product of pre-scientific imagination, rooted in the fearful infancy of our species. That belief in its literal truth still persists is, perhaps, the real wonder of the Bible — though it might be better attributed to the enduring power of childhood indoctrination, which at times borders on psychological abuse.
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