Imagine the Earth as a gigantic laboratory where experiments have been conducted for billions of years: terrestrial magnetism and atmospheric oxygen are two protagonists of this cosmic experiment, and we now know that they have been playing the same role for at least 540 million years.
It's no coincidence: when one grows, the other grows. When one weakens, the other falters. But why? This mysterious correlation has driven NASA scientists crazy, who still can't explain whether it is the magnetic field that controls the oxygen or vice versa.
A 540 Million Year Long Cosmic Puzzle
Weijia Kuang and his team at NASA's Goddard Space Flight Center have pieced together two seemingly unrelated puzzles. On one side, the history of Earth's geomagnetic field, written in the magnetic crystals of ancient volcanic eruptions. On the other, the evolution of atmospheric oxygen, traced through fossil carbon deposits left by prehistoric fires. The result? A correlation that leaves you breathless.
Earth's Magnetism and Oxygen Levels they grew up together throughout the Cambrian period, with a dramatic surge between 330 and 220 million years ago. We are not talking about vague similarities: the data They display such precise synchronization that it seems choreographed. As if the planet had a hidden conductor beating time for both its magnetic core and its breathable atmosphere.

Earth's Magnetism as Guardian of the Atmosphere
The most obvious explanation points to terrestrial magnetism as protector of the atmosphere. The magnetic field acts as an invisible shield, deflecting the solar wind that would otherwise blow away our atmosphere. Mars is a perfect example: it lost its magnetic field 4,2 billion years ago and is now a barren desert.
Earth's geodynamo, powered by the movements of molten iron in the outer core, generates a magnetic field that extends thousands of kilometers into space. This shield protects not only the atmosphere, but also the plants that produce oxygen through photosynthesis.
The stronger the field, the greater the protection from solar radiation that could harm plant life.
But there is another possibility that fascinates researchers.
The Plate Tectonics Hypothesis
Perhaps atmospheric oxygen influences the Earth's magnetism through plate tectonics. As continental plates move, they transport oxidized materials toward the Earth's core. These materials could alter the composition of the outer core, changing the dynamics of the geodynamo.
Benjamin Mills of the University of Leeds suggests that the movement of the continents could be the third wheel in this relationship. The formation of supercontinents like Pangea coincides perfectly with peaks in Earth's magnetism and atmospheric oxygen recorded 330 million years ago. Massive tectonic reorganizations may have created favorable conditions for both phenomena.
Earth's Magnetism and Breathability: A Mystery Looking to the Future
The correlation raises profound questions about the nature of planetary life. If Earth's magnetism is indeed linked to the respirability of the atmosphere, this changes everything in the search for life on other planets. Astronomers may have to revise their criteria for finding habitable worlds, looking not just for liquid water but also for strong magnetic fields.
As I was pointing out to you in this article, Earth has a date with destiny in a billion years, when atmospheric oxygen will disappear forever. But this new study suggests that perhaps we should also keep an eye on the evolution of the magnetic field.
Ravi Kopparapu, co-author of the study published in Science Advances, admits the humility of science in the face of this puzzle:
“A single mind cannot understand the entire Earth system. We are like children playing with Legos, each of us has a separate piece. We are trying to put it all together to see the big picture.”
What we do know is that for more than half a billion years, two fundamental forces of our planet have danced together. Earth's magnetism and the oxygen you breathe are not strangers: They are partners in a cosmic duet that allowed complex life to evolve.
And maybe, just maybe, every breath you take is a small celebration of this invisible alliance that holds the world together.