Earth's Magnetic Field is 550 Million Years Older Than Previously Thought

The Earth's radiation shield was found in a new study to be hundreds of millions of years older than previously determined.

According to BBC News, authors of a study published in the journal Nature Communications aged the Earth's magnetic shield at four billion years old. That would suggest the barrier protecting the atmosphere from outside radiation is about 550 million years older than previously thought.

Study lead author John Tarduno, a geophysicist at the University of Rochester, said in a press release the Earth's magnetic field is "important for the preservation of habitable conditions on Earth."

"The spin in iron atoms align relative to the Earth's magnetic field, and preserve that information unless the material is heated above a property called the Curie temperature," Tarduno told BBC News. "For magnetite this is 580C. When a mineral is heated to above its Curie temperature, it loses that information."

Examining the Earth's magnetic field could lead to a better understanding of the planet's liquid iron core and plate tectonics. For studies like Tarduno's to be possible, researchers will need magnetite, an ancient, organic magnetic iron oxide that holds magnetic field data in mineral form.

"We know the zircons have not been moved relative to each other from the time they were deposited," Tarduno said in the release. "As a result, if the magnetic information in the zircons had been erased and re-recorded, the magnetic directions would have all been identical.

"There has been no consensus among scientists on when plate tectonics began," he said. "Our measurements, however, support some previous geochemical measurements on ancient zircons that suggest an age of 4.4 billion years."