The temporary collapse of the Earth’s magnetic field 42,000 years ago caused a major upheaval climate change that has led to global environmental transformations and mass extinctions.
According to a new international study conducted by the University of New South Wales (UNSW), Sydney and the Museum of South Australia, this dramatic turning point in Earth’s history, mixed with storms, widespread auroras and cosmic radiation, was caused by pole reversal. Earth’s magnetic field and the change of the solar wind. The findings are published in Science (Read also: Researchers make objects to levitate led by light).
“For the first time in history, we were able to accurately date the time and environmental impact of the last reversal of the magnetic pole.”says Chris Turney, a professor at UNSW and co-author of the study.
The discoveries were made possible by kauri trees in New Zealand, which have been stored in sediments for more than 40,000 years. “Using ancient trees, we were able to measure and date the increase in atmospheric radiocarbon levels caused by the collapse of the Earth’s magnetic field,” Turney said in a statement.
While scientists already knew that magnetic poles were temporarily reversed 41-42,000 years ago, They did not know exactly how it influenced life on Earth. But researchers have managed to create a detailed timeline of how the Earth’s atmosphere has changed during this time, by analyzing the rings in ancient kauri trees.
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“Kauri trees are like the Rosetta Stone, helping us unite records of environmental changes in caves, ice cores and peatlands around the world.”says co-leader Professor Alan Cooper, an honorary researcher at the Museum of South Australia.
The researchers compared the recently created time scale with records from Pacific sites and used it to model the global climate, finding that rising ice sheets and glaciers in North America and large changes in the major belts of wind systems and tropical storms can be traced to the Adams event, named by researchers after British science fiction writer Douglas Adams.
It was a time when seemingly random cosmic events and extreme environmental changes coincided found around the world 42,000 years ago.
One of its first indications was that the megafauna of mainland Australia and Tasmania went through simultaneous extinction at that time.
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“This never seemed right, because it was a long time after the aborigines arrived, but it was about the same time that the Australian environment changed to its current arid state,” says Professor Cooper. The paper suggests that the event could explain many other evolutionary mysteries, such as the disappearance of Neanderthals and the sudden and widespread emergence of figurative art in caves around the world.
Colombian physicist Santiago Andrés Triana, from the Royal Observatory of Belgium, comments that The reversal of the magnetic poles is a phenomenon that has occurred several times in the past and its precise causes are not fully understood.
“We know that the magnetic field is generated by a dynamo effect in the liquid core of the Earth. The currents in that ocean of liquid iron generate magnetic fields which, in turn, provide more energy to these currents, in a feedback process that results in a large-scale magnetic field, such as the one we observe today. However, this process is not completely stable. The magnetic reversal of 42,000 years ago is proof of this, “says Triana.
Triana adds that “in this relatively short period of reverse polarity, the intensity of the magnetic field was much lower than the normal intensity. This allows more radiation from electrically charged particles in the Sun to reach the surface of our planet, causing substantial damage to the ozone layer and, in turn, affecting the climate and the environment in general.
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According to Triana, the magnetic field is weakening at present, albeit at a relatively slow pace: .
The magnetic inversion revealed by the Laschamps event, as the phenomenon described in the study is called, shows that surprising changes inside the Earth can take place on a very fast time scale (from a geological point of view) and can negatively affect the habitability of our planet. That is why it is important to study and understand as accurately as possible the processes that take place in the Earth’s core. Our future may depend on it “, says Triana.
EUROPA PRESS