Magnetic oceans and electric Earth


Applications Magnetic oceans and electric Earth 03/10/2016 14431 views 159 likes Oceans might not be thought of as magnetic, but they make a tiny contribution to our planet’s protective magnetic shield. Remarkably, ESA’s Swarm satellites have not only measured this extremely faint field, but have also led to new discoveries about the electrical nature of inner Earth. When salty ocean water flows through the magnetic field, an electric current is generated and this, in turn, induces a magnetic response in the deep region below Earth’s crust – the mantle. Thanks to Swarm’s precise measurements along with those from Champ – a mission that ended in 2010 after measuring Earth’s gravity and magnetic fields for more than 10 years – scientists have not only been able to find the magnetic field generated by ocean tides but, remarkably, they have used this new information to image the electrical nature of Earth’s upper mantle 250 km below the ocean floor. “These new results are important for understanding plate tectonics, the theory of which argues that Earth’s lithosphere consists of rigid plates that glide on the hotter and less rigid asthenosphere that serves as a lubricant, enabling plate motion.” Roger Haagmans, ESA’s Swarm mission scientist, explained, “It’s astonishing that the team has been able to use just two years’ worth of measurements from Swarm to determine the magnetic tidal effect from the ocean and to see how conductivity changes in the lithosphere and upper mantle.


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