Deep within the heart of Earth’s crust, a hidden record of our planet’s magnetic field, dating back 3.7 billion years, has been discovered. This remarkable finding, made possible through the meticulous analysis of ancient rocks excavated from Isula, Greenland, has provided scientists with their oldest estimates of the strength and direction of Earth’s magnetic shield.
Using the iron particles within the ancient rocks as natural magnets, researchers were able to decipher the magnetic field’s characteristics from that distant era. The results revealed that the magnetic field strength 3.7 billion years ago was approximately 15 microTesla – half the strength of our modern magnetic field. This discovery suggests that the magnetic field has remained relatively stable over billions of years, providing consistent protection against cosmic radiation and the Sun’s solar wind.
The stability of the magnetic field over such a vast expanse of time has profound implications for our understanding of Earth’s history and the emergence of life. The magnetic shield has played a pivotal role in deflecting harmful radiation, creating a habitable environment on our planet. As the Sun’s solar wind grew fiercer in the past, the magnetic field strengthened, providing increased protection and paving the way for life to flourish.
The team of researchers behind this study plans to continue their work, excavating ancient rocks from various locations around the globe, including Canada, Australia, and South Africa. Their aim is to further refine our understanding of the magnetic field’s age and evolution, shedding light on its crucial role in supporting and shaping life on Earth.
