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But we know, the magnetic field is there to protect us from solar winds. Then, how come its absence actually fuelled life on Earth?Story highlights
Earth's magnetic field is essentially the great protector of the planet, shielding it from the Sun's intense cosmic radiation. However, a new research has claimed that the Earth's magnetic field had vanished some 590 million years ago, and it actually created the best conditions for early life to flourish.
University of Rochester Earth scientist Wentao Huang and colleagues in their new paper write: "Earth's magnetic field was in a highly unusual state when macroscopic animals of the Ediacara fauna diversified and thrived."
In previous studies, it has been established that multi-cellular life evolved on the Earth some 565 million years ago (Ediacaran period). This period surprisingly coincides with the time when our planet's magnetic field has collapsed to its lowest levels.
But we know, the magnetic field is there to protect us from solar winds. Then, how come its absence actually fuelled life on Earth?
Scientists excavated igneous rocks from South Africa that formed billions of years ago and observed crystals in them and other 591 million-year-old rocks previously sampled from Brazil. It's significant because as these rocks form, they preserve the intensity of the Earth's magnetic field.
The researchers found that the level of magnetic field had dropped to the lowest levels 500 million years ago, 30 times weaker than it is today.
The period of low magnetic field lasted for nearly 26 million years, during which an explosion of biodiversity took place on our home planet.
"The new data confirming and extending the UL-TAFI strengthen a potential linkage with the Ediacaran evolution of macroscopic animals," Huang and colleagues write.
The scientists speculate that the lower magnetic field may have allowed more hydrogen ions to escape from Earth's atmosphere into space, which could have resulted in higher oxygen levels in the seas and skies.
Higher oxygen levels then led to the explosion of biodiversity, claimed the researchers.
"A complex animal ecosystem involving long food chains and predators requires still greater amounts of oxygen, as indicated by the exclusion of such complex ecosystems from the modern oxygen minimum zone," Huang and colleagues explain.
But how did the organisms escape the wrath of solar winds?
Scientists say the Earth's atmosphere and oceans may have acted as a shield for early life forms.
However, those massive organisms who roamed on land, without the protective shield of oceans, may have run into an evolutionary dead end during this phase.
(With inputs from agencies)
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