Earth’s core is the source of the very important but poorly understood magnetic field that surrounds the planet and extends outward.
One of physics’ great mysteries, it was first recorded about 180 years ago and when it was noticed to be weakening, the potential consequences, such as its effects on the biosphere, set alarm bells ringing.
However, new evidence shows that instead of diminishing, Earth’s magnetic field is perhaps merely fluctuating, as it has done over millennia. Using a set of 67 jars, all of them from between the eighth and second centuries B.C. from the region that was known as Judea at the time, scientists have gathered information about changes in the planet’s geomagnetic field in the course of those 600 years.