Scientists have discovered hidden magnetic messages in meteorites from the early solar system in meteorites.
Geologists from the University of Cambridge led by Dr. Richard Harrison, has captured information stored inside tiny magnetic regions in meteorite samples using the PEEM-Beamline at BESSY II.
This information captures the dying moments of the magnetic field during core solidification on a meteorite parent body, providing a sneak preview of the fate of Earth's own magnetic field as its core continues to freeze.
Meteorites were previously thought to have poor magnetic memories, with the magnetic signals they carry having been written and rewritten many times during their long journey to Earth. Harrison, however, identified specific regions filled with nanoparticles that were magnetically extremely stable. These "tiny space magnets" retain a faithful record of the magnetic fields generated by the meteorite's parent body.
Until now it was not clear whether ancient magnetic signals could be retained by stony-iron meteorites at all.
But Harrison took a much closer look. At the PEEM-Beamline of BESSY II, they found dramatic variation in magnetic properties as they went through the meteorite. They saw not only regions containing large, mobile magnetic domains, but also identified an unusual region called the cloudy zone containing thousands of tiny particles of tetrataenite, a super hard magnetic material.
They concluded that the tiny particles of just 50 to 100 nanometers in diameter hold on to their magnetic signal and don't change. So it was only these very small regions of chaotic looking magnetization that contain the information.
The results are published in Nature.