Rise of the Protector

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Earth’s magnetic field has long played an important role in preserving life on the planet. Now, scientists are shedding some new light onto its early origins, Popular Mechanics reported.

The magnetic field is powered by our planet’s iron core and protects all life from being blasted by dangerous cosmic rays from the Sun and other parts of outer space.

There is still debate about when it was first formed, but a new study on iron rocks discovered the earliest known evidence of the field’s existence.

An international research team analyzed well-preserved rocks collected from Greenland’s Isua Greenstone Belt dating some 3.7 billion years ago. They explained iron content in these samples matters because it can lock in the direction and strength of a magnetic field when it crystalizes.

To probe the magnetic information, the team first demagnetized the rocks in a lab and then remagnetized them. This method has the side effect of showing how powerful Earth’s magnetic field was 3.7 billion years ago.

The findings show that the early magnetic field from the Eoarchean period – around four to 3.6 billion years ago – had a strength of 15 microteslas, which is nearly half as strong as today’s field.

The study puts the timeframe around 200 million years earlier than previous magnetic field evidence, which also brings up questions about when the earliest lifeforms emerged.

The team suggested that life was still possible some 3.7 billion years ago despite a weak magnetic field and extremely harsh conditions – when Earth was getting bombarded by powerful solar winds.

Still, the study further reinforces the case that magnetic fields are necessary for life to emerge and an eventual increase in strength allows lifeforms to flourish.

This information could also assist astronomers when searching for life elsewhere in the universe, the authors noted.

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