We owe life on Earth as we know it to the planet’s magnetic field. It is this element that protects us from part of the radiation emanated by our star and the solar winds. Winds that would have made the water disappear from our oceans as happened on Mars.
But we could also owe life as we know it to its weakening.
591 million years ago. The Cambrian explosion could have had this paradoxical origin. According to new research, the weakening of the Earth’s magnetic field about 591 million years ago could have been instrumental in the increase in oxygen levels that occurred at the end of the Ediacaran period.
Explosion of life. The Ediacaran period is the last of the Precambrian phases and preceded an era of notable expansion of life on Earth, the so-called “Cambrian explosion.” It is estimated that life on Earth had begun billions of years earlier, but this was the period in which it diversified.
It was in this period in which complex life evolved and in which the different taxonomic phyla in which we classify the species of animals that we know today began to differentiate from each other. This explosion has conventionally been associated with an increase in oxygen levels on our planet.
Inefficient processes. Now the team responsible for the latest study has focused the focus of this event on the Earth’s magnetic field. They did so based on analyzes of the intensity of the field throughout geological history.
Different studies had already indicated that the magnetic field of our planet existed between 591 and 565 million years ago. The latter calculated that at the beginning of this interval the field was 30 times weaker than it is now. Also weaker than it was 2 billion years ago.
Complementary hypotheses. This period of magnetic weakening coincided with the period in which oxygen levels on the planet grew and researchers believe that this coincidence harbors a causal relationship. That is, the magnetic weakening caused oxygen levels to grow and this in turn caused an explosion of biodiversity on the planet.
How exactly? The hypothesis proposed by the team is based on the possibility that the magnetic winds could have affected the hydrogen ions in the atmosphere, dragging them with them and thus leaving room for the oxygen molecules.
This possibility is not contradictory to the dominant hypothesis until now, but rather complementary. Until now we had considered that it was the work of cyanobacteria that was responsible for this oxygenation period. The team published details of their study in the journal Communications Earth & Environment.
From Earth to Mars. This discovery has a curious parallel, that of Mars. As far as we know, the neighboring planet is a desert depopulated by life. Mars would have had liquid water oceans at the beginning of its existence but would have lost them, possibly after losing its magnetic field (or most of it).
Who knows what could have happened if our planet’s magnetic field had not recovered from its “slump.” Perhaps the most interesting question would be what would have happened to Mars if its protective field had been reanimated.
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Image | PaleoEquii