(Source: Southgate ARC)

The ESA just discovered a second magnetic field surrounding our planet

A trio of satellites studying our planet’s magnetic field have shown details of the steady swell of a magnetic field produced by the ocean’s tides.

Four years of data collected by the European Space Agency’s (ESA) Swarm mission have contributed to the mapping of this ‘other’ magnetic field, one that could help us build better models around global warming.

Physicist Nils Olsen from the Technical University of Denmark presented the surprising results at this year’s European Geosciences Union meeting in Vienna, explaining how his team of researchers managed to detail such a faint signature.

“It’s a really tiny magnetic field,” Olsen told BBC correspondent Jonathan Amos. “It’s about 2 – 2.5 nanotesla at satellite altitude, which is about 20,000 times weaker than Earth’s global magnetic field.”

On a fundamental level, both fields are the result of a dynamo effect produced by charged particles being sloshed around in a fluid.

The stronger magnetic field that tugs on our compass needle forms from the steady movement of molten rock deep under our feet.

This field also leaves its signature in the alignment of particles embedded in Earth’s crust, a pattern that has also been analysed in detail by Swarm

Read the full story at:
https://www.sciencealert.com/esa-swarm-satellite-map-ocean-tides-magnetic-field