A trio of satellites from the European Space Agency (ESA) Swarm mission, launched into space about four years ago to study the magnetic field of our planet, discovered the presence of another stable magnetic field. The compiled map of this field indicated an amazing fact, its source is ocean currents and currents, and entering data on this magnetic field into existing models will allow scientists to better understand the "work" of our planet and the processes taking place on it, including global warming.
“The second magnetic field of our planet is very small and weak,” says Nils Olsen, a physicist at the Technical University of Denmark. “Its strength at satellite altitude ranges from 2 to 2.5 nanotesla, which is about 20 thousand times less than the strength of the global magnetic field generated in the core of the Earth."
The second magnetic field of the planet, just like the main one, is the result of the work of a giant dynamo machine. Electrically charged ions of salts dissolved in seawater move along with streams and currents. And the movement of an electric charge, as we know from a school physics course, leads to the appearance of a magnetic field.
On a map compiled from data from the Swarm satellites, under normal conditions, it is difficult to distinguish even traces of the magnetic field generated by such a strong stream as the Gulf Stream. Weak signals from this field are simply buried in the background of a stronger global magnetic field. However, the magic wand in this case was the Moon, which attracts masses of water, which produces an impulse of the magnetic field, which can be registered by the satellite sensors.
We remind our readers that the three Swarm satellites were launched into space in 2013. Currently, these satellites move in different circular orbits at altitudes from 300 to 560 kilometers above the Earth's surface, collecting data on the planet's magnetic fields.
The magnetic field generated by seawater is another way to study Earth's oceans. The data on magnetic fields will make it possible to refine the mathematical models that describe the processes of movement of heat flows on our planet, which is a factor determining all global climatic changes.
"In addition, periodic magnetic signals can cause a weak response from the interior of the earth," says Niels Olsen. "This, in turn, can be used to determine the electrical properties of the earth's lithosphere and upper mantle."
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