Earth's Magnetic Field
Illustration of the invisible magnetic field lines generated by the Earth. Unlike a classic bar magnet, the matter governing Earth's magnetic field moves around. The flow of liquid iron in Earth's core creates electric currents, which in turn creates the magnetic field. Credit and copyright: Peter Reid, University of Edinburgh
Earth's magnetic field, which protects the planet from harmful blasts of solar radiation, is much older than scientists had previously thought. This invisible, protective shield likely existed shortly after the planet formed; a finding that could shed light on why Earth is habitable and Mars is not. Earth's magnetic field helped make life on the planet possible. Without our magnetic field, solar winds would strip away the planet's atmosphere and oceans.