A NEW study of previous reversals of Earth's magnetic field has shown a rapid shift within two centuries – a discovery that prompted researchers to warn of a potentially dire scenario.
According to a team of international scientists, including from the Australian National University (ANU), such an event in the future would increase the exposure of our planet to the sun's radiation and could damage billions of dollars by power and communication systems. to decimate throughout the world. globe.
The earth has a magnetic field that scientists think is generated by movement at the core of the planet. It is what gives us our north and south poles and competence compasses.
We have known for more than a century that the magnetic field of our planet is weakening at a rate of about five per cent per century, resulting in concerns that the magnetic piles of the Earth could quickly reverse – an event that could potentially have disastrous results. for life on Earth.
The last time the poles turned around was about 780,000 years ago and some commentators have expressed concern that we may be on our way to a new opportunity in the not too distant future. Historically, the magnetic north and south poles rotate every 300,000 years, so some say that we are too late.
The new research shows that reversals in the magnetic field can take place much faster than the thousands of years previously thought that this was necessary.
Professor Andrew Roberts of the ANU Research School for Earth Sciences said that the strength of the magnetic field decreased by about 90 percent when a field reversal occurred, making the earth much more vulnerable to the sun's radiation.
"The magnetic field of the earth, which exists for at least 3.45 billion years, provides a shield against the direct impact of solar radiation," he said in a statement issued by the ANU.
"Even with the strong magnetic field of the earth today, we are still susceptible to solar storms that could harm our electricity company."
From the electricity networks that power our computers to the satellites that make us watch TV, many facets of our lives depend on the Earth's magnetic field. It also behaves like an invisible force field that protects the earth from solar winds and harmful cosmic rays.
A dramatic decline in his strength as a result of a turnaround can make us vulnerable.
The study looked at the paleomagnetic record from 107,000 to 91,000 years ago, based on accurate magnetic analysis and radiometric dating of a stalagmite from a cave in south-western China.
"The record offers important insights into the old magnetic field behavior, which turned out to be much faster than previously thought," Prof. Roberts said.
The findings of the group were published in the journal Proceedings of the National Academy of Sciences in the United States of America (PNAS).
About 40,000 years ago, Earth's magnetic field underwent a dramatic "wobble" but did not completely disappear, the researchers believe. But the continuing weakening and in particular the expansion of a weak hole in the magnetic field in the South Atlantic, known as the South Atlantic Anomaly (SAA), has raised concerns that a major change could occur.
But a separate report that was also published in the PNAS magazine in May trivialized the idea that the poles are reversing.
Prof Roberts said that there is no reason to panic and hoped that we could develop ways to limit the effects of a future pool reversal.
"Hopefully such a event in the future will come a long way and we can develop future technologies to prevent major damage, whenever possible, from such events," he said.