Scientists from the University of Oxford and Massachusetts Institute of Technology conducted a study, the results of which show that the Earth’s magnetic field existing 3.7 billion years ago was surprisingly similar to modern. The study, published in the Journal of Geophysical Research, provides the earliest reliable estimate of the strength of Earth’s magnetic field.
The Earth’s magnetic field plays a crucial role in maintaining life, protecting us from cosmic radiation and charged particles of the solar wind. The exact date of the formation of a modern magnetic field has been unknown until now. By analyzing ancient iron-containing rocks from ISUA, Greenland, researchers were able to determine that the magnetic field strength at that time was about 15 microteslas, comparable to today’s values.
Professor Claire Nichols, a leading researcher from Oxford University, highlights the challenge of extracting reliable data from ancient rocks, stating that “when we started analyzing these samples in the laboratory and saw primary magnetic signals, it was really exciting.”
The study also suggests that although the magnetic field seemed relatively stable, the solar wind was much stronger in the past. This indicates that Earth’s protection from the solar wind has intensified over time, potentially aiding in the transition of life to land.
An important finding of the study is the impact of the magnetic field on atmospheric processes, such as the loss of Xenon gas from the atmosphere over 2.5 billion years ago. It is believed that the magnetic field may have played a role in removing xenon from the atmosphere by charging its particles.
Future research plans involve further exploration of ancient rocks in Canada, Australia, and South Africa to deepen understanding of the variability and strength of ancient magnetic fields. This research will also help determine the critical role of planetary magnetic fields in sustaining life and the evolution of atmospheres on planets.