Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The South Atlantic Anomaly is probably not an evidence of a reversing Earth’s magnetic field

02.05.2018

Within the research community it is a subject of debate whether this anomaly is a sign of an imminent reversal of the Earth’s magnetic poles. Based on a reconstruction of the Earth’s magnetic field of the past, scientists from the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences and the Universities of Iceland, Liverpool, and Nantes now show that the anomaly is probably not a precursor of a switching of the poles.

Earth‘s magnetic field serves as a shield against hazardous radiation from space, especially the Sun’s charged particle flux. Since 1840, the year systematic measurements began, the global strength of the magnetic field has decayed at a rate of about five percent per century.


Increased occurrence of radiation-induced technical satellite failures of the Swarm satellites (white spots) in the region of the South Atlantic Anomaly between April 2014 and June 2017.

I. Michaelis, GFZ

Since that time, a significant anomaly of reduced magnetic strength has appeared over the South Atlantic: the South Atlantic Anomaly. Within the research community it is a subject of debate whether this anomaly is a sign of an imminent reversal of the Earth’s magnetic poles.

Based on a reconstruction of the Earth’s magnetic field of the past, scientists from the Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences and the Universities of Iceland, Liverpool, and Nantes now show that the anomaly is probably not a precursor of a switching of the poles.

The area of the South Atlantic Anomaly is characterized by a significant reduction in the strength of Earth’s magnetic field compared with areas at similar geographic latitudes. Here, protection from harmful radiation from space is reduced. This leads, for example, to a higher rate of satellite communication blackouts or higher doses of radiation for passengers of long-distance flights.

Reversals of the Earth’s magnetic field have been common throughout Earth’s history. The process of a field reversal is accompanied by a reduction in field strength and reduced protection against hazardous radiation from space.

Within their new study, published in Proceedings of the National Academy of Sciences of the United States of America PNAS, the scientists reconstructed past changes in Earth’s magnetic field using paleomagnetic data from sediment cores and volcanic rocks from across the globe.

Magnetic minerals in the rocks and sediments “record” the orientation and strength of the Earth’s magnetic field at the time of rock formation. For the time interval of 50,000 to 30,000 years before present the data base is especially good, so that the scientists were able to model the changes of the magnetic field globally.

During this time interval there were two occasions when weak magnetic field over the South Atlantic and South America resembled today’s field. In both cases the field strength in this region increased again after some time and the anomaly disappeared. The low intensity areas did notlead to a reversal of the poles.

41,000 years ago, a short-lived reversal of the poles occurred, the so-called Laschamp excursion. During this time, Earth’s magnetic field switched polarity for less than one thousand years, with the pole returning to its original polarity. At the beginning of the excursion, the field showed a significantly different pattern of reduced magnetic strength across Earth’s surface than today.

Monika Korte, co-author of the study and team leader in the GFZ section Geomagnetism: “Based on our observations of the past 50,000 years we conclude that the South Atlantic Anomaly cannot be interpreted as a sign for the beginning of a reversal of the poles. Times of the past that, unlike the beginning of the Laschamp excursion, showed patterns of the magnetic field like today were not followed by a pole reversal. After some time the anomalies disappeared.”

The scientists can, however, not say how long today’s anomaly will persist. It is possible that the strength of the field will further decay for several centuries. The last reversal of the poles towards today’s orientation took place 780,000 years ago. It may take thousands of years before the magnetic field reverses again.

Original study:
Brown, M., Korte, M., Holme, R., Wardinski, I., Gunnarson, S., 2018. Earth’s magnetic field is probably not reversing. PNAS. DOI: 10.1073/pnas.1722110115

Ralf Nestler | Helmholtz-Zentrum Potsdam - Deutsches GeoForschungsZentrum GFZ
Further information:
http://www.gfz-potsdam.de/

More articles from Earth Sciences:

nachricht New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>