The Earth’s magnetic field is at least 3.7 billion years old.

In southwest Greenland, amid vast expanses of ancient ice, lies the famous Isua Belt of Green Cliffs, the oldest and best-preserved lithological formation on Earth. Here comes a revolutionary discovery: a team of scientists claims to have found the most primitive signal of Earth’s magnetic field, dating back to approximately 3.7 billion years ago. This magnetic field, a kind of invisible shield, protects the planet and its life from cosmic radiation and solar wind.

According to scientific theory, the Earth’s magnetic field is created by the dynamics of an outer core of molten iron and nickel, which rotates around an inner iron ball. This movement generates electric fields, which in turn support the Earth’s magnetic field, acting as a natural dynamo.

The resulting magnetosphere extends beyond the atmosphere, protecting life on the surface from harmful radiation from space. However, this magnetic shield was not always present, and its origin and evolution are important for understanding the early history of life on Earth and phenomena such as the lack of magnetism on other planets such as our neighbor Venus.

A recent discovery by an international team of scientists has revealed the presence of magnetite, an iron-containing mineral with highly magnetic properties, in the green stones of Isua. This magnetite preserves the Earth’s magnetic field signal as it was 3.7 billion years ago, during a high-temperature geological event that changed the composition of rocks. Professor Claire Nichols from the University of Oxford and lead author of the study describes how these stones were magnetized during this process, providing a record of the early magnetic field.

Protection that allowed you to live

This discovery challenges previous records and confirms the presence of a magnetic field on Earth. So far, the oldest evidence of paleomagnetism has been found in rocks of South Africa and Australia. Research published in the journal Journal of Geophysical Researchshows that the magnetic field strength 3.7 billion years ago was approximately 15 microtesla (a unit of measurement equal to one millionth of a tesla, which in the International Electromagnetic Induction System measures the presence and intensity of a magnetic field). fields Today field data is 30 microtesla.

Although the dates do not coincide with the beginning of life on Earth, this discovery is critical to understanding how magnetic defenses have evolved over time and its relationship to the history of life on the planet. Nichols emphasizes that his research does not confirm or disprove the presence of life during this period, but rather provides valuable information about the environmental conditions of that time.

The Earth’s magnetic field is essential to life on Earth, protecting the surface from solar and cosmic radiation. Understanding its evolution over millennia also sheds light on fundamental geological processes such as the formation of the solid core and plate tectonics. The discovery opens up new perspectives on the early history of our planet and its role in the development of life, and also provides valuable information about neighboring planets that lack magnetism and atmosphere.

The discovery of the Isua green rocks represents a major milestone in the scientific study of Earth’s magnetism, opening new perspectives on planetary evolution and the history of life on Earth. @mundiario