Earth’s ‘life-saver’ magnetic field collapsed 590 million years ago, for all good reasons

Earth'smagnetic field is essentially the great protector of the planet, shielding it from the Sun’sintense cosmic radiation. However, a new research has claimed that theEarth’s magneticfield 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 colleaguesintheir newpaper write:“Earth'smagnetic field was in a highly unusual state when macroscopic animals of the Ediacara fauna diversified and thrived."

In previousstudies, it has beenestablished that multi-cellular life evolved on the Earth some 565 million years ago (Ediacaran period).This period surprisinglycoincides with the time when ourplanet’smagnetic fieldhascollapsed to its lowest levels.

But weknow,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 crystalsin themand other 591 million-year-old rocks previously sampled from Brazil.It’ssignificant because as these rocks form, they preserve the intensity of the Earth’smagnetic field.

The researchers found that thelevel of magnetic fieldhad dropped to the lowest levels 500 million years ago, 30 times weaker than it is today.

Theperiod oflow 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 fromEarth'satmosphere 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.

"Acomplex 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 theEarth’satmosphere and oceans may have acted as a shield for early life forms.

However, those massive organisms who roamed onland,without the protective shield of oceans,may have run into an evolutionary dead end during this phase.

(With inputs from agencies)