Evidence Of Strong Early Magnetic Field Around Earth

Eddie Gonzales Jr. – MessageToEagle.com – An invisible magnetic field protects our planet. It’s vital for life on Earth’s surface because it protects the planet from harmful solar wind and cosmic rays from the sun.

Given the importance of the magnetic field, scientists’ knowledge can provide clues to understanding the future evolution of Earth, as well as the evolution of other planets in the solar system.

The rotation and convection of molten iron at the center of the planet creates a dynamo effect, generating Earth’s magnetic field. source

Now, researchers from the University of Rochester try to figure out how the field has changed throughout Earth’s history. Their study shows that the magnetic field that first formed around Earth was even stronger than scientists previously believed.

“This research is telling us something about the formation of a habitable planet,” John Tarduno, the William R. Kenan, Jr., Professor of Earth and Environmental Sciences and Dean of Research for Arts, Sciences, and Engineering at Rochester, said in a press release.

“One of the questions we want to answer is why Earth evolved as it did and this gives us even more evidence that the magnetic shielding was recorded very early on the planet.”

Today, Earth’s magnetic shield is generated in the planet’s core. The intense heat in Earth’s dense inner core causes the outer core–composed of liquid iron–to swirl and churn, generating electric currents, and driving a phenomenon called the geodynamo, which powers Earth’s magnetic field. The currents in the liquid outer core are strongly affected by the heat that flows out of the solid inner core.

Because of the location and extreme temperatures of materials in the core, scientists aren’t able to directly measure the magnetic field.

See also:

Earth’s Magnetic Fields Do Affect The Human Brain- Yes, We Have A Magnetic Sense

Waves Emitted In Earth’s Inner Core Cause Anomalies In The Magnetic Field – Magnetic Jerks Explained

Fortunately, minerals that rise to Earth’s surface contain tiny magnetic particles that lock in the direction and intensity of the magnetic field at the time the minerals cool from their molten state.

Using the latest data, the researchers dated and analyzed zircon crystals–the oldest known terrestrial materials–collected from sites in Australia. The zircons, which are about two-tenths of a millimeter, contain even smaller magnetic particles that lock in the magnetization of the earth at the time the zircons were formed.

Previous research by Tarduno found that Earth’s magnetic field is at least 4.2 billion years old and has existed for nearly as long as the planet. Earth’s inner core, on the other hand, is a relatively recent addition: it formed only about 565 million years ago.

While the researchers initially believed Earth’s early magnetic field had a weak intensity, the new zircon data suggests a stronger field. But, because the inner core had not yet formed, the strong field that originally developed 4 billion years ago must have been powered by a different mechanism.

“We think that mechanism is chemical precipitation of magnesium oxide within Earth,” Tarduno says.

The magnesium oxide was likely dissolved by extreme heat related to the giant impact that formed Earth’s moon. As the inside of Earth cooled, magnesium oxide could precipitate out, driving convection and the geodynamo. The researchers believe inner Earth eventually exhausted the magnesium oxide source to the point that the magnetic field almost completely collapsed 565 million years ago.

But the formation of the inner core provided a new source to power the geodynamo and the planetary magnetic shield Earth has today.

The research, published in the journal PNAS.

Written by Eddie Gonzales Jr. – MessageToEagle.com Staff