The planet’s global magnetic field arises from what scientists call dynamo: a stream of molten metal inside the planet’s core that produces an electric current. That dynamo is what makes the compass needle to take a position in accordance with the magnetic poles of the Earth. However, researchers know that the dynamo of Mars disappeared billions of years ago.
A new discovery by an international team of scientists published in the journal Science Advances brought them closer to understanding how long the Mars dynamo worked. “We found that it worked 4.5 billion and 3.7 billion years ago. This is a large part of the planet’s evolution – these data are very different from the usual ideas of research, ”said Anna Mittelholz, one of the authors of the study. “Dynamo will allow us to analyze the thermal history of the planet”.
For the study, scientists have analyzed in detail the geomagnetic history of the planet – including stones lying on the surface of Mars and rocks located below the surface. They can be used as an archive of records, especially for stones of volcanic nature. This is because they arise as lava, but then, under the influence of a magnetic field and other factors, they cool and harden. So the materials are arranged in accordance with the magnetic field of the planet.
Magnetism in certain rocks on the surface of Mars indicates that the Martian dynamo was active between 4.3 or 4.2 billion years ago, but the lack of magnetism in the three large basins formed 3.9 billion years ago convinced scientists that dynamo was inactive. Scientists also discovered low-intensity magnetic fields near the Boreali basin, located in the northern hemisphere of the planet, and formed about 4.5 billion years ago.