Study: Earth's magnetic field is almost the same as it was 3.7 billion years ago

According to the news in Discover Magazine, using rocks 3.7 billion years old, researchers from the University of Oxford and the Massachusetts Institute of Technology (MIT) have found that the Earth's magnetic field is almost the same today as it was 3.7 billion years ago .

Through careful study of rocks excavated from the Greenland island's Isua greenstone belt, researchers found that the strength of the magnetic field 3.7 billion years ago was 15 microtesla. This strength is half the strength of the modern magnetic field.

The researchers achieved this success by studying iron particles on ancient rocks, which act as natural magnets by recording the strength and direction of the magnetic field.

The magnetic field protects the Earth from cosmic radiation and solar winds.

Located 150 kilometers northeast of Nuuk, the capital of Greenland, the Isua greenstone belt contains the oldest rocks on Earth.

Emphasis on “exciting”

Claire Nichols, a geoscientist at the University of Oxford and lead author of the study, said in a statement that the results are an important step in understanding the role of the ancient magnetic field when life was just emerging on Earth.

Nichols pointed out that it is very difficult to obtain reliable insights from a 3.7 billion-year-old rock and noted that it is exciting to observe the emergence of important magnetic signals when analyzing the samples in the laboratory.

Is a magnetic field necessary to support life?

It is very difficult to find rocks that indicate the age of the Earth's magnetic field. Heat along tectonic plates can alter any traces preserved in rocks.

However, the rocks found on the island of Greenland sat on a thick continental crust that protected them from warming.

The researchers also plan to excavate ancient rocks from Canada, Australia and South Africa for future studies.

Further insight into the age of the magnetic field and its evolution could help researchers understand whether a magnetic field is necessary to sustain life.

The research was published in the Journal of Geophysical Research.