The mystery of Earth’s geomagnetic field has been solved, with the bottom line being that the poles won’t flip any time soon.
Over the past 200 years scientists have been measuring the intensity of our planet’s geomagnetic field. As it was observed to drop, estimates have proposed that Earth’s geomagnetic field might hit rock bottom in approximately two millennia. In turn, this would spell havoc for the planet left unprotected in the face of solar particles.
As the intensity of the geomagnetic field drops, the Earth’s poles flip polarity periodically. However, the geomagnetic field intensity is an up-and-down process. It might be dropping now, yet it returns to a stable intensity albeit in thousands of years.
Admittedly, the shift in the geomagnetic field intensity sound a little terrifying. Solar radiation hitting the planet is bound to meddle with electronics from the smallest to entire power grids. Genetic mutations are on the list as well as animals’ internal navigation systems.
Scientists with the Massachusetts Institute of Technology (MIT) took a closer look at the data and announced in the their research paper featuring in the Proceedings of the National Academy of Sciences that the mystery of Earth’s geomagnetic field has been solved. Moreover, the geomagnetic field shift isn’t in the cards just yet. And the Earth’s poles will keep polarity as it for a long time to come.
To be able to conclude their research, the MIT team calculated the average stable geomagnetic field intensity of our planet over the course of the past 5 million years. What Earth is experiencing today is in fact twice the historical average. According to Huapei Wang, postdoctoral researcher with the MIT Department of Earth, Atmospheric and Planetary Science:
“It makes a huge difference, knowing if today’s field is a long-term average or is way above the long-term average. Now we know we are way above the unstable zone”.
A second team of researchers from Rutgers University in collaboration with the MIT team used ancient rocks collected from the Galapagos Islands to measure the planet’s paleomagnetic field. Galapagos Islands are located on the planet’ equator. The volcanoes provided plenty of material indicative of the Earth’s geomagnetic field at the time the rocks cooled.
Volcanic rocks from the equator are relevant as the equator should pinpoint the stable configuration of our planet’s geomagnetic field. In this state the intensity is equally distributed between the Earth’s poles while half is at the equator. That is called a dipole.
In addition to these volcanic rocks, another batch of rocks from Antarctica were studied by researchers with the Scripps Institution of Oceanography of the UCSD.
Under laboratory conditions, the rocks were measured for remanent magnetization, heated, cooled and placed in the presence of a magnetic field. The first and the latter are proportional. As such, the link between the intensity of the Earth’s geomagnetic field at the equator and the poles at similar moments in time could be accurately measured.
Photo Credits: Flickr