Would life exist on Earth if this had not happened 500 million years ago?

The Earth’s magnetic field is critical to life; Without it, solar radiation would destroy it all. However, a new study published in the journal Earth and environment connection, assumes that The Earth’s magnetic field has not always been stable and all indications are that life would not exist on Earth if this magnetic field had not collapsed almost completely 500 million years ago.

Brief and necessary collapse

Researchers led by scientists from the University of Rochester have discovered a surprising record of decreasing Earth’s magnetic field. for 26 million years, 591–565 million years ago, and this weakening marked a transformative era in the history of life on Earth.

According to experts, a short-term collapse of the magnetic field could allow the development of complex life forms on the planet during Ediacaran periodduring which complex multicellular organisms emerged, setting the stage for the subsequent explosion of life.

Records show that there is an increase in diversity among soft-bodied animals. 575-565 million years ago, probably due to increased oxygen content in the atmosphere and ocean; an event coinciding with a decline in the strength of the Earth’s magnetic field (which has changed direction many times over millions of years).

“Previous ideas about the emergence of the spectacular Ediacaran fauna included genetic or environmental factors, but the proximity to the ultra-low geomagnetic field prompted us to consider environmental issues and, in particular, oxygenation of the atmosphere and ocean,” explained the dean of research from the Faculty of Arts and Sciences and Faculty of Engineering and Applied Science and co-author of the work, John Tarduno.

How can you find out?

The strength and direction of the magnetic field throughout Earth’s history is something scientists can study by studying rocks that preserve information about the local magnetic field at the moment of their formation; That is, minerals can keep track of the strength of the magnetic field at this moment due to the magnetic particles they contain.

Therefore, the researchers examined a sample of plagioclase crystals from Fabiana Gabbros Pass, Brazil, deposited 591 million years ago. What they found was evidence of the lowest magnetic field ever recorded—one-thirtieth the level we have today. And also with a big difference compared to previous dates. The magnetic field was only 3% of the intensity it has today.

Essentially, the magnetic field was in a very unusual state as macroscopic animals flourished and evolved. Recall that the Ediacara fauna was the first complex form of life on Earth.

“They were distinguished by their resemblance to early animals; some even reached a size of more than one meter (three feet) and were mobile, indicating that they likely required more oxygen compared to earlier life forms,” explains Tarduno.

Interestingly, it has long been thought that a weak magnetic field may have been harmful to previous life forms due to exposure to constant radiation and solar winds. This does not appear to be what happened to the Ediacaran fauna, the prehistoric species that They flourished between 600 and 540 million years ago.

Tarduno’s team suggests that the increase in oxygen percentage may have been caused by atmospheric hydrogen leaking through Earth’s weakened shield. This allowed life to flourish, of course due to the fact that it did not last long. Previously, researchers discovered that the geomagnetic field regained strength in the later Cambrian period, when most animal groups begin to appear in the fossil record. If the weakened state of the magnetic field persisted much longer, perhaps all the water on Earth would eventually disappear and Our planet could become a dry place like Mars.

“If the extremely weak field had persisted beyond Ediacaran, the Earth could have looked very different from the water-rich planet it is today: the loss of water could have gradually dried out the Earth,” explains the expert.

And why did the magnetic field decrease so much?

Scientists don’t know. Perhaps if we one day discover life on other planets, we will be able to resolve this eluding dilemma.

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