Emily Chan
Around 591 million years ago, Earth’s magnetic field almost collapsed. The near-disaster may have contributed to the evolution of larger and more diversified life forms, according to a new study published in the journal Communications Earth and Environment.
Our planet’s magnetic field helps protect us from radiation, solar winds, and extreme temperature changes.
The study found that the Earth’s magnetic field experienced a phase of drastic weakening that lasted for 26 million years. It occurred during the Ediacaran period.
At that time, a large amount of oxygen was present in the Earth’s atmosphere and oceans, allowing for the first plants and animals to emerge from the sea.
Back then, sea creatures were just disc-like forms, fronds, and fans—nothing much like the organisms we see today.
Scientists believe that the weak magnetic field let a lot of solar radiation through, which removed much of the hydrogen and other light gases from the atmosphere. As a result, there were plenty of oxygen atoms left behind for organisms to use.
A team of researchers analyzed rocks containing crystals that cooled over a period of thousands of years. The rocks show evidence of the strength of the magnetic field at different times of the Earth’s development.
From southern Brazil, a rock revealed that 591 million years ago, the magnetic field was 30 times weaker than it is today.
However, in South Africa, a two-billion-year-old rock suggested that the magnetic field was just as strong as it is now.
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