Life on Earth became possible when the planet’s solid inner core emerged hundreds of millions of years ago, according to new research.
Scientists said that about 565 million years ago, the strength of the Earth’s magnetic field fell to 10% of its current strength.
It then suddenly bounced back just before the animals emerged in what scientists call the Cambrian Explosion or “biological big bang”.
The team said this rejuvenation happened at the same time that Earth’s inner core was forming and was likely the cause.
This magnetic field is vital for life on Earth because it protects the planet from radiation emitted by the sun. It is generated in our planet’s outer core by swirling liquid iron about 1,800 miles below our feet.
The swirling liquid iron causes electric currents, resulting in a phenomenon called geodynamo which produces the magnetic field.
The researchers said the rejuvenation means Earth is avoiding the fate of Mars, which once had a magnetic field before it disappeared.
The glowing planet is vulnerable to solar radiation and has no oceans.
Although the Earth might not have been guaranteed to suffer the same fate if its magnetic field had not reappeared, it would have lost a lot more water and be much drier than it is today. today.
The US team said the rejuvenation occurred over a few tens of millions of years, which is actually rapid on the scale of geologic time.
In their research paper, the academics established key dates in the inner core’s history, including a more accurate estimate of its age.
The Earth is made up of layers: the crust, where life is found; the mantle, the thickest layer of the Earth; the molten outer core and the solid inner core, which is, in turn, composed of an outermost inner core and an innermost inner core.
For decades, scientists have tried to understand how the Earth’s magnetic field and core have changed throughout our planet’s history.
They cannot directly measure the magnetic field because it is so hot and so far below the Earth’s surface.
Minerals that rise to the Earth’s surface contain tiny magnetic particles that lock into the direction and strength of the magnetic field as they cool from their molten state.
For the study, the team used a carbon dioxide laser and a high-tech magnetometer to analyze crystals from the rock anorthosite.
These have tiny magnetic needles which are “perfect” for recording magnetism.
By studying the magnetism locked in ancient crystals, the team established two important dates in the formation of the inner core’s history.
They said the magnetic field began to renew itself 550 million years ago, 15 million years after it collapsed.
The team said the rapid reformation was caused by the formation of a strong inner core, which recharged the outer core and restored the strength of the magnetic field.
Scientists said that 100 million years later, the structure of the growing inner core changed, and the boundary between the innermost and outermost inner core became clear.
These changes coincide with changes at about the same time in the structure of the overlying mantle, due to plate tectonics on the surface.
Study author Professor John Tarduno of the University of Rochester in New York said: “This research really highlights the need for something like a growing inner core that maintains a magnetic field. throughout the lifetime – several billion years – of a planet.
“The Earth would certainly have lost a lot more water if the Earth’s magnetic field had not been regenerated.
“The planet would be much drier and very different from today’s planet.”
The results were published in the journal Nature Communication.
Produced in association with SWNS.
This story was provided to Newsweek by Zenger News.