The aurora borealis, seen here over northern Iceland, happens when electrically charged particles accelerate along the lines of the Earth's magnetic field into the upper atmosphere, where they collide with gas atoms, causing the atoms to give off light.

(Mariana Suarez/AFP via Getty Images)

At a Glance

Earth's original magnetic field formed 4.2 billion years ago.Zircon crystals indicate the field was much stronger than previously thought.The field shielded the planet from cosmic rays and solar winds.

Earth's first magnetic field 4.2 billion years ago was much stronger than previously thought and may have provided the protection needed for life to begin on the planet, according to a new study.

Clues about this field come from minuscule grains of magnetite, an iron-containing mineral, inside zircon crystals found in rocks from the Jack Hills of Western Australia.

Researchers at the University of Rochester have been studying the crystals in hopes of learning more about the evolution of Earth and , according to a news release from the university.

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"This research is telling us something about the formation of a habitable planet," John Tarduno, the study's author and a University of Rochester professor, said in the 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."

The magnetic field protected Earth from cosmic rays and solar winds. It prevented the planet's water from being blasted into space and , according to a report by Live Science.

In order to determine the past magnetic field direction and intensity, the researchers dated and analyzed zircon crystals collected from sites in Australia. The zircons are about two-tenths of a millimeter and contain even smaller magnetic particles that lock in the magnetization of the earth at the time the zircons were formed. Here, a zircon crystal is placed within the "O" on a dime, for scale.

(University of Rochester/John Tarduno)

"This early magnetic field was extremely important because it shielded the atmosphere and water removal from the early Earth when solar winds were most intense," Tarduno said. "The mechanism of field generation is almost certainly important for other bodies like other planets and exoplanets."

Scientists theorize Mars had a magnetic field when it was formed, but it collapsed about 4 billion years ago. With no protective shield, the planet's oceans and much of its atmosphere disappeared.

"Once Mars lost its magnetic shielding, it then lost its water," Tarduno said. "But we still don't know why the magnetic shielding collapsed. Early magnetic shielding is really important, but we're also interested in the sustainability of a magnetic field. This study gives us more data in trying to figure out the set of processes that maintain the magnetic shield on Earth."

Earth's current field is generated by the spinning of the planet's outer core, which is caused by heat from the inner core. Previous research by Tarduno estimated the.

Tarduno's current study, published Monday in the , found that the ancient magnetic field was powered by a different means: magnesium oxide.

Magnesium oxide that dissolved in the all-liquid core during the same impact that created Earth's moon, was precipitated out of the core and into the mantle. The movement generated a magnetic field, according to the new study.

The ancient zircon crystals showed that field was much stronger than previously thought.

When the magnesium oxide ran out, the magnetic field almost completely collapsed. That was about 565 million years ago, when the inner core formed.