An illustration showing mysterious waves (red) moving across the outermost layer of Earth’
An illustration showing mysterious waves (red) moving across the outermost layer of Earth’s outer core. (Image credit: ESA/Planetary Visions)New type of magnetic wave discovered in Earth’s core | Live ScienceScientists have detected a completely new type of magnetic wave that surges through Earth’s outer core every seven years, warping the strength of our planet’s magnetic field in the process.The waves — dubbed “Magneto-Coriolis” waves because they move along the Earth’s axis of rotation, per the Coriolis effect — creep from East to West in tall columns that can travel up to 930 miles (1,500 kilometers) per year, the researchers wrote in a March 21 paper in the journal Proceedings of the National Academy of Sciences. Using a fleet of European Space Agency (ESA) satellites, the team pinpointed the mysterious waves to the outermost layer of Earth’s liquid outer core, right where that layer meets the rocky mantle — roughly 1,800 miles (2,900 km) below the planet’s surface.According to the researchers, the existence of these waves could help explain mysterious fluctuations in the planet’s magnetic field, which is generated by the movement of liquid iron in the planet’s outer core. Satellite measurements of the magnetic field taken over the last 20 years show that the field’s strength dips every seven years or so, coinciding with the oscillations of these newfound waves.“Geophysicists have long theorized over the existence of such waves, but they were thought to take place over much longer time scales,” lead study author Nicolas Gillet, a researcher at the Grenoble Alpes University in France, said in a statement. “Our research suggests that other such waves are likely to exist, probably with longer periods — but their discovery relies on more research." … -- source link
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