The interactions between the earth and the cosmos discreetly shape the history of our planet. If meteorites or solar eruptions sometimes mark spirits, other upheavals, quieter, nevertheless leave lasting traces in climates, species and human behaviors. There are several millennia, a rare phenomenon has weakened the main bulwark of our planet against radiation. The episode of a weakened terrestrial magnetic field then sparked a series of chain reactions which would have transformed much more than the sky.
The less armored atmosphere saw the northern lights reach lower latitudes, appearing much further south than their usual area. The archives of dark circles (14C) and ice carrots (10be), analyzed by an international team led by Alan Cooper and Chris Turney, indicate a spectacular increase in carbon 14, witness to this increase in cosmic radiation. On a planetary scale, these modifications affected atmospheric chemistry, in particular by an increased destruction of ozone, which would have contributed to temporary climate cooling.
A weakened terrestrial magnetic field and its consequences on the human body
The increased radiation to the earthly surface would not have been without effect on living beings, as Scitechdaily points out. Researchers are advancing the idea that genetic mutations and certain congenital anomalies may have been favored by this increase in exposure to energy particles. One of the markers of this environmental stress could reside in the gradual disappearance of Neanderthal, whose groups were particularly affected during this period.
On the physiological level, prolonged exposure to ultraviolets leads to known deleterious effects. Burns, DNA degradations, eye disorders or alterations of the immune system are among the hypotheses envisaged to explain the adaptations observed at that time. Some populations would have developed biological or behavioral responses to compensate for this increase in radiative stress.
Biology is not always enough. The behavior comes to reinforce. This is how we can interpret certain archaeological traces, which testify to an increase in new behaviors at this pivotal time.
Survival strategies that reinvent prehistoric lifestyles
Archeology reveals a shift in contemporary human practices of this weakening of the terrestrial magnetic field. In Blombos, in South Africa, excavations have uncovered ocher fragments and engraved tools dating precisely from this period. These pigments were probably used to cover the skin, forming a barrier against ultraviolet rays, as suggested by the work published in Science.
The occupation of caves also seems to be generalized in certain regions, providing natural protection against solar radiation, but also a space to develop more symbolic cultural expressions. The rise of rock art, bone work, body ornament or funeral rites would mark a turning point in human societies, favored by environmental constraints.
Finally, the comparison between Homo Sapiens and Neanderthal shows a striking contrast. The first develops more varied adaptive strategies, disperses more widely, and seems to resist these fast changes better. This divergence could not only reflect different cognitive capacities, but also better behavioral plasticity.
With an unwavering passion for local news, Christopher leads our editorial team with integrity and dedication. With over 20 years’ experience, he is the backbone of Wouldsayso, ensuring that we stay true to our mission to inform.
