Importance of having magnetic field

2001/02/20 Carton Virto, Eider - Elhuyar Zientzia

• Fisika
• Astrofisika

The solar wind reaches all the planets of the solar system, the shed of charged particles. In the case of Earth, its magnetic field (the magnetosphere) acts as a shield, diverting particles and making its life possible. So far, the researchers thought that Mars has never been so hidden, but according to recent studies had one.

In 1999, NASA researchers found that the oldest territories on Mars showed signs of exposure to a global magnetic field. However, around the impact craters were not seen. This means that the magnetic field disappeared before the impacts occurred, that is, 500 million years after its foundation, more than 4,000 million years ago. This figure surprised several.

Since 1999, Mars Global Surveyor has made measurements of all kinds, the strength of the solar wind, the residual atmosphere of Mars and the magnetic field footprint. South of Mars, remains of the atmosphere, in the regions where the magnetic field has left solid remains on the rocks. According to this, the ancient magnetism was able to protect part of the atmosphere of the solar wind. But when it disappeared, it left the atmosphere dominated by the solar wind, which also disappeared.

Why? Why did the magnetic field of Mars disappear? There is no sure answer, but there is a theory related to plate tectonics. The truth is that the magnetic field of the planets is produced by the polarization of iron in the cores. On the ground plate tectonics increase this effect, but on Mars there is no plate movement. According to the theory, the magnetic field created by the polarization of iron without plates is too weak to withstand the solar wind. If the motion of the plates were also finished on Earth, for 100 million years the magnetosphere would disappear and with it the atmosphere and life.

Therefore, although at some point Mars could develop atmosphere and life, it seems that it was sterilized very quickly. However, with the aim of justifying NASA's passion for finding life or the traces of life on Mars, they wanted to emphasize that Mars is not completely dead: in the underground there can still be water.