Since the creation ofthe that surrounds it has never ceased to vary while ensuring its protective function against . These variations can go up to of . This process has been repeated many times over geological time. It is, so to speak, a banal phenomenon that occurs on average every 200,000 years, although it is difficult to observe any regularity.
An anomaly, but no reversal in the program!
Currently we are able to measure the intensity and orientation of theterrestrial and to track its evolution. However, scientists note that the intensity of the magnetic field has decreased by about 10% for about 180 years. A magnetic field weakening area has also formed in the South Atlantic off the South American coast. The presence of this brought up the idea that a could be imminent. This may be the first inversion documented directly by mankind.
A new study published in, shows that this is not the case. This type of anomaly would actually be a recurring phenomenon over the past 9,000 years in conjunction with the normal fluctuations in the magnetic field generated by Convection forces in the outer core of the earth.
The researchers’ modeling therefore led to the conclusion that the South Atlantic anomaly could likely disappear over the next 300 years without a magnetic field reversal occurring.
Does South Atlantic Magnetic Anomaly Herald Imminent Magnetic Reversal?
Is a magnetic polarity reversal imminent? Maybe yes… or maybe not. To find out, paleomagneticians searched the archives ofof 34 past eruptions on the island of Sainte-Hélène, at the heart of the South Atlantic magnetic anomaly.
Article bypublished on August 22, 2020
The phenomenon of polarity reversal is all the more fascinating when it comes to a strong temporary weakening of the intensity of the Earth’s magnetic shield. However,have occurred many times in Earth’s history, and there is no convincing evidence that each time they have profoundly altered the climate or the biosphere. Nothing really special seems to be happening when the blue planet’s magnetic field is at its weakest, at least as long as it remains very transient on a geological scale, which counts a million years as a unit of time. Luckily then mergerthe British-American sci-fi disaster film directed by Jon Amiel and released in 2003 is destined to stay on screens.
For some time, however, the overall intensity of the earth’s magnetic field has been decreasing and. If the phenomenon were to occur today, it would surely disrupt our technologically advanced civilization based on electricity, electronics and satellites, especially in the case of one fierce sun.
We understand quite well that the Earth’s magnetic field is the combined product of its rotation and theturbulent part of its core in from and from who is . L’ (Of sodium) can even reproduce that the self-excitation thus generated and the magnetic inversions, but we do not yet know how to make accurate predictions about the evolution of the as one would do for the climate and the atmosphere, although we still managed to do it .
The South Atlantic Magnetic Anomaly and the Memory of Saint Helena Volcano
For some time, some have wondered if the famous South Atlantic magnetic anomaly discussed by Futura in the previous article below was not a precursor to the magnetic pole reversal. Keep in mind that this is a region of the Atlantic where the intensity of the Earth’s magnetic field, which is usually roughly dipolar, like that of a materials bar magnet, is significantly weakened. It is also noted that it is associated with malfunctions from nearby satellites over this region.
In an attempt to better understand the nature and significance of this anomaly, paleomagneticians have unearthed the Earth’s geomagnetic records preserved in volcanic rocks emitted from the island of Saint Helena, which lies at the center of the Atlantic anomaly. They have just published the results of their work in a famous article(PNAS).
Here’s what Yael Engbers, PhD student at the University of Liverpool and lead author of the article, said in PNAS : “Our study provides the first long-term analysis of the magnetic field in this region, going back millions of years. It shows that the South Atlantic magnetic field anomaly is not a singular anomaly, similar anomalies existed eight to eleven million years ago. This is the first time that the irregular behavior of the Earth’s magnetic field in the South Atlantic region has been shown on such a long time scale. This suggests that the South Atlantic anomaly is a recurring feature and is unlikely to be a sign of an impending reversal. Our work also supports previous studies that suggested a link between the South Atlantic Anomaly and anomalous seismic featureslower and outer core. This brings us closer to a direct connection between the behavior of the Earth’s magnetic field and the properties of the Earth’s interior.”.
Why is Earth’s magnetic field weakening over the South Atlantic?
Article bypublished on 05/26/2020
thegradually fading south of the Atlantic, a phenomenon that puzzles more than one geophysicist. While some will argue that this is the work of the Atlanteans, scientists appeal to Heaven.
Although invisible to oursEarth’s magnetic field plays an essential role in sustaining life on our blue planet. All at the same time and shield, it deflects the deadly particles of the solar winds, the last remnants of which bloom and austral to the poles of the planet. However, this is on the wane in a region between Africa and South America, a region so well known for its magnetic anomalies that it’s the subject of its own myths. To understand this amazing phenomenon, scientists have turned to this a of three mini-satellites launched from the November 22, 2013 to study our magnetosphere.
Cluster, a magnetic anomaly in the Atlantic
The magnetic field is created by the convection movements of the Earth’s outer core: surrounding the inner core,this sphere of Liquid composed mainly of iron and nickel acts like a real dynamo. That they generate, shift and change. Recent studies have observed this over tens of kilometers per year. But the South Atlantic magnetic anomaly (or cluster) is somewhat different, and has puzzled scientists for many decades.
Although the overall strength of the Earth’s magnetic field has decreased over the past two centuries, the cluster appears to be taking its own course. Between 1970 and 2020, the field strength in this region fell from 24,000 to 22,000 nanotesla, while the anomaly continues to move westward at a rate of 20 kilometers per year. More recently, within the last five years, a second low-intensity focus appears to have emerged over South West Africa, suggesting that the anomaly may split into two separate cells.
This visualization illustrates the evolution of the South Atlantic magnetic anomaly recorded by the swarm over the past five years. © Swarm, ESA
The existence of the cluster challenges the reductionist notion one might have of the mechanics at the origin of the Earth’s magnetic field. A simple dipole model describing an earth acting like a magnet,the occurrence of these anomalies. For this reason, in November 2013, ESA launched the Swarm mission to explore our magnetosphere. ” We’re lucky to have the Swarm satellites with us to study the evolution of the South Atlantic anomaly, from the German Center for Geoscientific Research. The challenge now is to understand the processes causing these changes at the heart of the earth. »
The current dominant hypothesis is that of a polar reversal occurring every 250,000 years on average. With the last occurring nearly 780,000 years ago, a new reversal may be on the agenda. Whatever happens, the strange behavior of the Earth’s magnetic field bodes well for us on Earth. The only ones affected will be the low orbiting satellites, which may experience some malfunctions during their passage over this mysterious area that is still misunderstood.