© Illustration courtesy of Michael Osadciw (University of Rochester, Rochester, NY) and and John A. Tarduno.Artist rendition of early Earth and Mars 4.2 billion years ago with internally generated magnetic fields. The long life of the geodynamo and magnetic shielding prevented loss of the ocean on Earth, whereas the collapse of the Martian magnetic field contributed to its loss of water.
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. Credit: University of Rochester / John Tarduno
Deep within Earth, swirling liquid iron generates our planet's protective magnetic field.
This magnetic field is invisible but is vital for life on Earth's surface: it shields the planet from harmful solar wind and cosmic rays from the sun.Given the importance of the magnetic field, scientists have been trying to figure out how the field has changed throughout Earth's history. That knowledge can provide clues to understanding the future evolution of Earth, as well as the evolution of other planets in the solar system.
New research from the University of Rochester provides evidence that the magnetic field that first formed around Earth was even stronger than scientists previously believed. The research, published in the journal
PNAS, will help scientists draw conclusions about the sustainability of Earth's magnetic shield and whether or not there are other planets in the solar system with the conditions necessary to harbor life.
Comment: Data from Chinese satellite shedding light on cosmic rays